WorldWideScience

Sample records for crossed-slot cavity-backed antenna

  1. Crossed-Slot Cavity-Backed Antenna with Improved Hemispherical Coverage

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav; Østergaard, Allan

    2005-01-01

    The paper presents the results of the investigation of the crossed-slot cavity-backed antenna with the complementary crossed electric dipoles added to compensate the circularly polarized (CP) radiation pattern degradation near the horizon. Dependences of the radiation characteristics...... of the modified crossed-slot cavity-backed antenna on the length, width and height of the crossed electric dipoles are shown. Effects of a finite size ground plane are taken into account due to a full wave electromagnetic analysis software utilized in the parametrical investigations. Simulated and measured...... results for a selected antenna configuration prove that the properly adjusted crossed electric dipoles are able to improve the coverage and CP polarization characteristics of the crossed-slot cavity-backed antenna....

  2. A Design of Wide Band and Wide Beam Cavity-Backed Slot Antenna Array with Slant Polarization

    Directory of Open Access Journals (Sweden)

    Huiying Qi

    2016-01-01

    Full Text Available Design of antenna array under the limitation of restricted size is a challenging problem. Cavity-backed slot antenna is widely used because of its advantages of small size, wide band, and wide beam. In this paper, a design of wide band and wide beam cavity-backed slot antenna array with the slant polarization is proposed. To obtain wide band and wide beam with limited size, the inverted microstrip-fed cavity-backed slot antenna (IMF-CBSA is adopted as the element of 1 × 4 antenna array. The slant polarized antennas and their feeding networks are adopted because of their simple structures. The performance of the proposed antenna array is verified by the simulations and experiments. The measured VSWR < 2 bandwidth is 55% at the center frequency 21.8 GHz, and the gain is larger than 12.2 dB. Experimental results demonstrate that the proposed design achieves wide band and beam with the size of 68 mm × 56 mm × 14.5 mm.

  3. Ka-Band Slot-Microstrip-Covered and Waveguide-Cavity-Backed Monopulse Antenna Array

    Directory of Open Access Journals (Sweden)

    Li-Ming Si

    2014-01-01

    Full Text Available A slot-microstrip-covered and waveguide-cavity-backed monopulse antenna array is proposed for high-resolution tracking applications at Ka-band. The monopulse antenna array is designed with a microstrip with 2×32 slots, a waveguide cavity, and a waveguide monopulse comparator, to make the structure simple, reduce the feeding network loss, and increase the frequency bandwidth. The 2×32 slot-microstrip elements are formed by a metal clad dielectric substrate and slots etched in the metal using the standard printed circuit board (PCB process with dimensions of 230 mm  ×  10 mm. The proposed monopulse antenna array not only maintains the advantages of the traditional waveguide slot antenna array, but also has the characteristics of wide bandwidth, high consistence, easy of fabrication, and low cost. From the measured results, it exhibits good monopulse characteristics, including the following: the maximum gains of sum pattern are greater than 24 dB, the 3 dB beamwidth of sum pattern is about 2.2 degrees, the sidelobe levels of the sum pattern are less than −18 dB, and the null depths of the difference pattern are less than −25 dB within the operating bandwidth between 33.65 GHz and 34.35 GHz for VSWR ≤ 2.

  4. A PML-FDTD ALGORITHM FOR SIMULATING PLASMA-COVERED CAVITY-BACKED SLOT ANTENNAS. (R825225)

    Science.gov (United States)

    A three-dimensional frequency-dependent finite-difference time-domain (FDTD) algorithm with perfectly matched layer (PML) absorbing boundary condition (ABC) and recursive convolution approaches is developed to model plasma-covered open-ended waveguide or cavity-backed slot antenn...

  5. Ultra-Broad Band Radar Cross Section Reduction of Waveguide Slot Antenna with Metamaterials

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2016-06-01

    Full Text Available To reduce the radar cross section of a waveguide slot antenna, a three-layer metamaterial is presented based on orthogonal double split-ring resonators. The absorption characteristics of three-layer metamaterial are demonstrated by simulation. Moreover, the metamaterials have been loaded on common waveguide slot antenna according to the surface current distribution. The ultra-broad band radar cross section reduction of the antenna with metamaterials had been theoretically and experimentally investigated by radiating and scattering performances. Experimental and simulated results showed that the proposed antenna with metamaterials performed broadband radar cross section reduction from 3.9 GHz to 18 GHz and the gain had been improved due to the coupling effect between slot and the period structure. The maximal radar cross section reduction achieved 17.81 dB at 8.68 GHz for x-polarized incidence and 21.79 dB at 6.25 GHz for y-polarized waves.

  6. Elevated CPW-Fed Slotted Microstrip Antenna for Ultra-Wideband Application

    Directory of Open Access Journals (Sweden)

    Chandan Kumar Ghosh

    2012-01-01

    Full Text Available Elevated-coplanar-waveguide- (ECPW- fed microstrip antenna with inverted “G” slots in the back conductor is presented. It is modeled and analyzed for the application of multiple frequency bands. The changes in radiation and the transmission characteristics are investigated by the introduction of the slots in two different positions at the ground plane (back conductor. The proposed antenna without slots exhibits a stop band from 2.55 GHz to 4.25 GHz while introducing two slots on the back conductor, two adjacent poles appear at central frequencies of 3.0 GHz and 3.9 GHz, respectively, and the antenna shows the ultra-wideband (UWB characteristics. The first pole appears at the central frequency of 3.0 GHz and covers the band width of 950 MHz, and the second pole exists at a central frequency of 3.90 GHz covering a bandwidth of 750 MHz. Experimental result shows that impedance bandwidth of 129% (S11<-10 dB is well achieved when the antenna is excited with both slots. Compared to most of the previously reported ECPW structures, the impedance bandwidth of this antenna is increased and also the size of the antenna becomes smaller and more suitable for many wireless applications like PCS (1850–1990 MHz, WLAN (2.4–2.484 GHz, WiMAX (2.5–2.69 GHz and 5.15–5.85 GHz, and also X-band communication.

  7. Wideband, Low-Profile, Dual-Polarized Slot Antenna with an AMC Surface for Wireless Communications

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2016-01-01

    Full Text Available A wideband dual-polarized slot antenna loaded with artificial magnetic conductor (AMC is proposed for WLAN/WIMAX and LTE applications. The slot antenna mainly consists of two pairs of arrow-shaped slots along the diagonals of the square patch. Stepped microstrip feedlines are placed orthogonally to excite the horizontal and vertical polarizations of the antenna. To realize unidirectional radiation and low profile, an AMC surface composed of 7 × 7 unit cells is designed underneath a distance of 0.09λ0 (λ0 being the wavelength in free space at 2.25 GHz from the slot antenna. Both the dual-polarized slot antenna and the AMC surface are fabricated and measured. Experimental results demonstrate that the proposed antenna achieves for both polarizations a wide impedance bandwidth (return loss 10 dB of 36.7%, operating from 1.96 to 2.84 GHz. The isolation between the two input ports keeps higher than 29 dB whereas the cross-polarization levels basically maintain lower than −30 dB across the entire frequency band. High front-to-back ratios better than 22 dB and a stable gain higher than 8 dBi are obtained over the whole band.

  8. Radiation Characteristics of the Cavity Backed Antenna in Conducting Cone

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A technique using finite element and boundary integral method (FE-BI) and reciprocity theorem is presented to analyze the radiation characteristics of cavity backed antenna mounted on a conducting cone. The electric fields inside the cavity and on the aperture are obtained using finite element and boundary integral method. The far-field characteristic of the antenna is computed using reciprocity theorem. The paper begins with a general description of the method. An application of this method is given and the numerical result is compared with the experimental result.

  9. Wideband Cavity Backed Spiral Antenna for Stepped Frequency Ground Penetrating Radar

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne; Lenler-Eriksen, Hans-Rudolph

    2005-01-01

    A 1.7 turn cavity backed coplanar waveguide to coplanar strip-fed logarithmic uniplanar spiral antenna is presented and compared to a 1.5 turn spiral antenna. The 1.7 turn spiral antenna has a wide beamwidth, are circular polarised and has a bandwidth with a return loss better than 6 dB in the fr......B in the frequency band from 0.25 GHz to 4.5 GHz (18:1). The antenna is useful for Ground Penetrating Radar (GPR)....

  10. Antennas in inhomogeneous media

    CERN Document Server

    Galejs, Janis; Fock, V A; Wait, J R

    2013-01-01

    Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil

  11. A Novel Manufacturing Process for Compact, Low-Weight and Flexible Ultra-Wideband Cavity Backed Textile Antennas

    Directory of Open Access Journals (Sweden)

    Dries Van Baelen

    2018-01-01

    Full Text Available A novel manufacturing procedure for the fabrication of ultra-wideband cavity-backed substrate integrated waveguide antennas on textile substrates is proposed. The antenna cavity is constructed using a single laser-cut electrotextile patch, which is folded around the substrate. Electrotextile slabs protruding from the laser-cut patch are then vertically folded and glued to form the antenna cavity instead of rigid metal tubelets to implement the vertical cavity walls. This approach drastically improves mechanical flexibility, decreases the antenna weight to slightly more than 1 g and significantly reduces alignment errors. As a proof of concept, a cavity-backed substrate integrated waveguide antenna is designed and realized for ultra-wideband operation in the [5.15–5.85] GHz band. Antenna performance is validated in free space as well as in two on body measurement scenarios. Furthermore, the antenna’s figures of merit are characterized when the prototype is bent at different curvature radii, as commonly encountered during deployment on the human body. Also the effect of humidity content on antenna performance is studied. In all scenarios, the realized antenna covers the entire operating frequency band, meanwhile retaining a stable radiation pattern with a broadside gain above 5 dBi, and a radiation efficiency of at least 70%.

  12. Slot-Coupled Barbel Antenna

    DEFF Research Database (Denmark)

    Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

    2016-01-01

    A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

  13. Scattering by cavity-backed antennas on a circular cylinder

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.

    1994-01-01

    Conformal arrays are popular antennas for aircraft, spacecraft, and land vehicle platforms due to their inherent low weight and drag properties. However, to date there has been a dearth of rigorous analytical or numerical solutions to aid the designer. In fact, it has been common practice to use limited measurements and planar approximations in designing such non-planar antennas. The finite element-boundary integral method is extended to scattering by cavity-backed structures in an infinite, metallic cylinder. In particular, the formulation specifics such as weight functions, dyadic Green's function, implementation details and particular difficulties inherent to cylindrical structures are discussed. Special care is taken to ensure that the resulting computer program has low memory demand and minimal computational requirements. Scattering results are presented and validated as much as possible.

  14. Slot Antenna for Wireless Temperature Measurement Systems

    DEFF Research Database (Denmark)

    Acar, Öncel; Jakobsen, Kaj Bjarne

    2016-01-01

    This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

  15. Vertically Polarized Omnidirectional Printed Slot Loop Antenna

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

    2015-01-01

    A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

  16. Vertically Polarized Omnidirectional Printed Slot Loop AntennaPrinted Slot Loop Antenna (invited)

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper

    2015-01-01

    and in-phase fields in the slot in order to obtain an omnidirectional radiation pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due...

  17. Slotted Circularly Polarized Microstrip Antenna for RFID Application

    Directory of Open Access Journals (Sweden)

    S. Kumar

    2017-12-01

    Full Text Available A single layer coaxial fed rectangular microstrip slotted antenna for circular polarization (CP is proposed for radio frequency identification (RFID application. Two triangular shaped slots and one rectangular slot along the diagonal axis of a square patch have been embedded. Due to slotted structure along the diagonal axis and less surface area, good quality of circular polarization has been obtained with the reduction in the size of microstrip antenna by 4.04 %. Circular polarization radiation performance has been studied by size and angle variation of diagonally slotted structures. The experimental result found for 10-dB return loss is 44 MHz with 10MHz of 3dB Axial Ratio (AR bandwidth respectively at the resonant frequency 910 MHz. The overall proposed antenna size including the ground plane is 80 mm x 80 mm x 4.572 mm.

  18. Radiation and scattering by cavity-backed antennas on a circular cylinder

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.

    1993-01-01

    Conformal arrays are popular antennas for aircraft and missile platforms due to their inherent low weight and drag properties. However, to date there has been a dearth of rigorous analytical or numerical solutions to aid the designer. In fact, it has been common practice to use limited measurements and planar approximations in designing such non-planar antennas. The finite element-boundary integral method is extended to scattering and radiation by cavity-backed structures in an infinite, metallic cylinder. In particular, the formulation specifics such as weight functions, dyadic Green's function, implementation details, and particular difficulties inherent to cylindrical structures are discussed. Special care is taken to ensure that the resulting computer program has low memory demand and minimal computational requirements. Both scattering and radiation parameters are computed and validated as much as possible.

  19. Slot-coupled CW standing wave accelerating cavity

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

    2017-05-16

    A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

  20. Evaluation of detectable angle of mid-infrared slot antennas

    Science.gov (United States)

    Obara, R.; Horikawa, J.; Shimakage, H.; Kawakami, A.

    2017-07-01

    For evaluations of a mid-infrared (MIR) detectors with antenna, we constructed an angular dependence measurement system of the antenna properties. The fabricated MIR detector consisted of twin slot antennas and a bolometer. The area of the slot antennas was designed to be 2.6 × 0.2 μm2 as to resonate at 61 THz, and they were located parallel and separated 1.6 μm each other. The bolometer was fabricated using by a 7.0-nm thick NbN thin film, and located at the center of the twin antennas. We measured polarization angle dependence and directivity, and showed that the MIR antennas have polarization dependence and directivity like radiofrequency antennas.

  1. broadband, low sidelobe, zero height, slotted circular disk antenna

    African Journals Online (AJOL)

    of argument rr where J? = jwµ.(cross-section. Having determined the Hertzian vector, the el".ctromagnetic field distribution at the slot of the antenna can be obtained by substituting 'Tr', hack into the field equations. The results are given hy the ...

  2. User manual for EXCALIBUR: A FE-BI numerical laboratory for cavity-backed antennas in a circular cylinder, version 1.2

    Science.gov (United States)

    Kempel, Leo C.

    1994-01-01

    The Finite Element-Boundary Integral (FE-BI) technique was used to analyze the scattering and radiation properties of cavity-backed patch antennas recessed in a metallic groundplane. A program, CAVITY3D, was written and found to yield accurate results for large arrays without the usual high memory and computational demand associated with competing formulations. Recently, the FE-BI approach was extended to cavity-backed antennas recessed in an infinite, metallic circular cylinder. EXCALIBUR is a computer program written in the Radiation Laboratory of the University of Michigan which implements this formulation. This user manual gives a brief introduction to EXCALIBUR and some hints as to its proper use. As with all computational electromagnetics programs (especially finite element programs), skilled use and best performance are only obtained through experience. However, several important aspects of the program such as portability, geometry generation, interpretation of results, and custom modification are addressed.

  3. Design of Ultra-Wideband Tapered Slot Antenna by Using Binomial Transformer with Corrugation

    Science.gov (United States)

    Chareonsiri, Yosita; Thaiwirot, Wanwisa; Akkaraekthalin, Prayoot

    2017-05-01

    In this paper, the tapered slot antenna (TSA) with corrugation is proposed for UWB applications. The multi-section binomial transformer is used to design taper profile of the proposed TSA that does not involve using time consuming optimization. A step-by-step procedure for synthesis of the step impedance values related with step slot widths of taper profile is presented. The smooth taper can be achieved by fitting the smoothing curve to the entire step slot. The design of TSA based on this method yields results with a quite flat gain and wide impedance bandwidth covering UWB spectrum from 3.1 GHz to 10.6 GHz. To further improve the radiation characteristics, the corrugation is added on the both edges of the proposed TSA. The effects of different corrugation shapes on the improvement of antenna gain and front-to-back ratio (F-to-B ratio) are investigated. To demonstrate the validity of the design, the prototypes of TSA without and with corrugation are fabricated and measured. The results show good agreement between simulation and measurement.

  4. Implementation and investigation of circular slot UWB antenna with dual-band-notched characteristics

    Directory of Open Access Journals (Sweden)

    DadashZadeh Gholamreza

    2011-01-01

    Full Text Available Abstract The design and analysis of an ultra wideband aperture antenna with dual-band-notched characteristics are presented. The proposed antenna consists of a circular ring exciting stub on the front side and a circular slot on the back ground plane. By utilizing a parasitic strip and a T-shaped stub on the antenna structure, two notched bands of 850 MHz (3.5-4.35 GHz and 900 MHz (5.05-5.95 GHz are achieved. The proposed antenna is fabricated and measured. Measured results show that this antenna operates from 2.3 GHz to upper 11 GHz for voltage standing wave ratio less than 2, except two frequency notched bands of 3.5-4.35 and 5.05-5.95 GHz. Moreover, the experimental results show that proposed antenna has stable radiation patterns and constant gain. A conceptual circuit model, which is based on the measured impedance of the proposed antenna, is also shown to investigate the dual-band-notched characteristics.

  5. FDTD Analysis of U-Slot Rectangular Patch Antenna

    Science.gov (United States)

    Luk, K. M.; Tong, K. F.; Shum, S. M.; Lee, K. F.; Lee, R. Q.

    1997-01-01

    The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

  6. Low profile frequency agile MIMO slot antenna with TCM characterization

    KAUST Repository

    Ghalib, Asim

    2017-06-07

    In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.

  7. Wideband Circularly Polarized Printed Ring Slot Antenna for 5 GHz – 6 GHz

    Science.gov (United States)

    Nasrun Osman, Mohamed; Rahim, Mohamad Helmi A.; Jusoh, Muzammil; Sabapathy, Thennarasan; Rahim, Mohamad Kamal A.; Norlyana Azemi, Saidatul

    2018-03-01

    This paper presents the design of circularly polarized printed slot antenna operating at 5 – 6 GHz. The proposed antenna consists of L-shaped feedline on the top of structure and circular ring slot positioned at the ground plane underneath the substrate as a radiator. A radial and narrow slot in the ground plane provides coupling between the L-shaped feedline and circular ring slot. The circular polarization is realized by implementing the slits perturbation located diagonally to perturb the current flow on the slot structure. The antenna prototype is fabricated on FR4 substrate. The simulated and measured results are compared and analyzed to demonstrate the performance of the antenna. Good measured of simulated results are obtained at the targeted operating frequency. The simulated -10dB reflection coefficient bandwidths and axial ratio are 750 MHz and 165 MHz, respectively. The investigation on the affect of the important parameters towards the reflection coefficient and axial are also presented. The proposed antenna is highly potential to be used for wireless local area network (WLAN) and wireless power transfer (WPT).

  8. A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

    Directory of Open Access Journals (Sweden)

    X. Liu

    2016-04-01

    Full Text Available A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC composite surface is estimated by array factor analysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuseness-like and expands the bandwidth of radar cross section (RCS reduction. Secondly, the metal surface of waveguide slot antenna (WSA is replaced by the octagonal ring arrangement composite surface (ORACS. The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancellation principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that the novel antenna after loading with the ORACS, the gain is improved by 5dB; the bandwidth of RCS reduction (reduction greater than 10dB is 5.24-5.92 GHz.

  9. Slot Parameter Optimization for Multiband Antenna Performance Improvement Using Intelligent Systems

    Directory of Open Access Journals (Sweden)

    Erdem Demircioglu

    2015-01-01

    Full Text Available This paper discusses bandwidth enhancement for multiband microstrip patch antennas (MMPAs using symmetrical rectangular/square slots etched on the patch and the substrate properties. The slot parameters on MMPA are modeled using soft computing technique of artificial neural networks (ANN. To achieve the best ANN performance, Particle Swarm Optimization (PSO and Differential Evolution (DE are applied with ANN’s conventional training algorithm in optimization of the modeling performance. In this study, the slot parameters are assumed as slot distance to the radiating patch edge, slot width, and length. Bandwidth enhancement is applied to a formerly designed MMPA fed by a microstrip transmission line attached to the center pin of 50 ohm SMA connecter. The simulated antennas are fabricated and measured. Measurement results are utilized for training the artificial intelligence models. The ANN provides 98% model accuracy for rectangular slots and 97% for square slots; however, ANFIS offer 90% accuracy with lack of resonance frequency tracking.

  10. Quad-Band U-Slot Antenna for Mobile Applications

    Directory of Open Access Journals (Sweden)

    R. L. Ruiz

    2006-06-01

    Full Text Available In this paper, two different planar quad-band antennas are designed, modeled, fabricated and measured. Subsequently, the antennas are redesigned using an electromagnetic band gap substrate (EBG. Those new planar antennas operate in four frequency bands: 900 MHz, 1 800 MHz (both GSM, 1 900 MHz (USA and 2 400 to 2 500 MHz (Bluetooth The antenna has four narrow U-shaped slots etched to the patch. Using software, CST Microwave Studio [1], Zeland IE3D [2], and FEMLAB [3], simulations have been carried out to investigate the antenna's performance and characteristics. The antennas designed have been also built and measured to compare the real results with those obtained from the simulations.

  11. Frequency Reconfigurable Circular Patch Antenna with an Arc-Shaped Slot Ground Controlled by PIN Diodes

    Directory of Open Access Journals (Sweden)

    Yao Chen

    2017-01-01

    Full Text Available In this paper, a compact frequency reconfigurable circular patch antenna with an arc-shaped slot loaded in the ground layer is proposed for multiband wireless communication applications. By controlling the ON/OFF states of the five PIN diodes mounted on the arc-shaped slot, the effective length of the arc-shaped slot and the effective length of antennas current are changed, and accordingly six-frequency band reconfiguration can be achieved. The simulated and measured results show that the antenna can operate from 1.82 GHz to 2.46 GHz, which is located in DCS1800 (1.71–1.88 GHz, UMTS (2.11–2.20 GHz, WiBro (2.3–2.4 GHz, and Bluetooth (2.4–2.48 GHz frequency bands and so forth. Compared to the common rectangular slot circular patch antenna, the proposed arc-shaped slot circular patch antenna not only has a better rotational symmetry with the circular patch and substrate but also has more compact size. For the given operating frequency at 1.82 GHz, over 55% area reduction is achieved in this design with respect to the common design with rectangular slot. Since the promising frequency reconfiguration, this antenna may have potential applications in modern multiband and multifunctional mobile communication systems.

  12. Compact Elliptically Tapered Slot Antenna with Non-uniform Corrugations for Ultra-wideband Applications

    Directory of Open Access Journals (Sweden)

    F. G. Zhu

    2013-04-01

    Full Text Available A small size elliptically tapered slot antenna (ETSA fed by coplanar waveguide (CPW for ultra-wideband (UWB applications is proposed. It is printed on an FR4 substrate and occupies a size of 37×34×0.8 mm^3. A pair of quarter circular shapes is etched on the radiator to reduce the size. To overcome the limitation of uniform corrugation, non-uniform corrugation is utilized to reduce the cross-polarization level. A parametric study is carried out to investigate the effects of circular cut and corrugations. In order to validate the design, a prototype is fabricated and measured. Both simulated and measured results confirm that the proposed antenna achieves a good performance of a reflection coefficient below -10 dB from 3.1 GHz to 10.6 GHz, including a maximum antenna gain of 8.1dBi, directional patterns in the end-fire direction, low cross-polarization level below -20 dB and linear phase response. The antenna is promising for applications in UWB impulse radar imaging.

  13. Compact broadband circularly polarised slot antenna for universal UHF RFID readers

    DEFF Research Database (Denmark)

    Xu, Bo; Zhang, Shuai; Liu, Yusha

    2015-01-01

    A compact broadband circularly polarised (CP) slot antenna is designed for universal ultra-high-frequency (UHF) radio frequency identification (RFID) readers. The antenna consists of an L-shaped metal strip and a square-slot-loaded ground plane with four tuning stubs. The total size is 100 mm×100mm......×1.6 mm. The measured –10 dB impedance bandwidth is 40.7% (772–1166 MHz) and the measured 3 dB axial ratio (AR) bandwidth is 13.9% (840–965 MHz). Both the impedance and AR bandwidth cover the worldwide UHF RFID band....

  14. Transmission-enabled fiber Fabry-Perot cavity based on a deeply etched slotted micromirror.

    Science.gov (United States)

    Othman, Muhammad A; Sabry, Yasser M; Sadek, Mohamed; Nassar, Ismail M; Khalil, Diaa A

    2018-06-01

    In this work, we report the analysis, fabrication, and characterization of an optical cavity built using a Bragg-coated fiber (BCF) mirror and a metal-coated microelectromechanical systems (MEMS) slotted micromirror, where the latter allows transmission output from the cavity. Theoretical modeling, using Fourier optics analysis for the cavity response based on tracing the propagation of light back and forth between the mirrors, is presented. Detailed simulation analysis is carried out for the spectral response of the cavity under different design conditions. MEMS chips of the slotted micromirror are fabricated using deep reactive ion etching of a silicon-on-insulator substrate with different device-etching depths of 150 μm and 80 μm with aluminum and gold metal coating, respectively. The cavity is characterized as an optical filter using a BCF with reflectivity that is larger than 95% in a 300 nm range across the E-band and the L-band. Versatile filter characteristics were obtained for different values of the MEMS micromirror slit width and cavity length. A free spectral range (FSR) of about 33 nm and a quality factor of about 196 were obtained for a 5.5 μm width aluminum slit, while an FSR of about 148 nm and a quality factor of about 148 were obtained for a 1.5 μm width gold slit. The presented structure opens the door for wide spectral response transmission-type MEMS filters.

  15. High-Q silicon-on-insulator slot photonic crystal cavity infiltrated by a liquid

    International Nuclear Information System (INIS)

    Caër, Charles; Le Roux, Xavier; Cassan, Eric

    2013-01-01

    We report the experimental realization of a high-Q slot photonic crystal cavity in Silicon-On-Insulator (SOI) configuration infiltrated by a liquid. Loaded Q-factor of 23 000 is measured at telecom wavelength. The intrinsic quality factor inferred from the transmission spectrum is higher than 200 000, which represents a record value for slot photonic crystal cavities on SOI, whereas the maximum of intensity of the cavity is roughly equal to 20% of the light transmitted in the waveguide. This result makes filled slot photonic crystal cavities very promising for silicon-based light emission and ultrafast nonlinear optics

  16. Tri-Band CPW-Fed Stub-Loaded Slot Antenna Design for WLAN/WiMAX Applications

    Science.gov (United States)

    Li, Jianxing; Guo, Jianying; He, Bin; Zhang, Anxue; Liu, Qing Huo

    2016-11-01

    A novel uniplanar CPW-fed tri-band stub-loaded slot antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. Dual resonant modes were effectively excited in the upper band by using two identical pairs of slot stubs and parasitic slots symmetrically along the arms of a traditional CPW-fed slot dipole, achieving a much wider bandwidth. The middle band was realized by the fundamental mode of the slot dipole. To obtain the lower band, two identical inverted-L-shaped open-ended slots were symmetrically etched in the ground plane. A prototype was fabricated and measured, showing that tri-band operation with 10-dB return loss bandwidths of 150 MHz from 2.375 to 2.525 GHz, 725 MHz from 3.075 to 3.8 GHz, and 1.9 GHz from 5.0 to 6.9 GHz has been achieved. Details of the antenna design as well as the measured and simulated results are presented and discussed.

  17. Paper-based inkjet-printed tri-band U-slot monopole antenna for wireless applications

    KAUST Repository

    Abutarboush, Hattan

    2012-01-01

    Realization of a U-slot tri-band monopole antenna on a low-cost paper substrate using inkjet-printed technology is presented for the first time. The U-shaped slot is optimized to enhance the bandwidth and to achieve tri-band operation of 1.57, 3.2, and 5 GHz with measured impedance bandwidths of 3.21%, 28.1%, and 36%, respectively. The antenna is fabricated through a metallic nanoparticle ink on a standard commercial paper. Thus, the antenna can be used to cover the GPS, WiMAX, HiperLAN/2, and WLAN. The antenna has a compact size of 12 × 37.3 × 0.44 mm3 , leaving enough space for the driving electronics on the paper substrate. The impedance bandwidth, current distributions, radiation patterns, gain, and efficiency of the antenna have been studied through computer simulations and measurements. © 2002-2011 IEEE.

  18. Design of a Short/Open-Ended Slot Antenna with Capacitive Coupling Feed Strips for Hepta-Band Mobile Application

    Directory of Open Access Journals (Sweden)

    Kyoseung Keum

    2018-01-01

    Full Text Available In this paper, a planar printed hybrid short/open-ended slot antenna with capacitive coupling feed strips is proposed for hepta-band mobile applications. The proposed antenna is comprised of a slotted ground plane on the top plane and two capacitive coupling feed strips with a chip inductor on the bottom plane. At the low frequency band, the short-ended long slot fed by strip 1 generates its half-wavelength resonance mode, whereas the T-shaped open ended slot fed by strip 2 generates its quarter-wavelength resonance mode for the high frequency band. The antenna provides a wide bandwidth covering GSM850/GSM900/DCS/PCS/UMTS/LTE2300/LTE2500 operation bands. Moreover, the antenna occupies a small volume of 15 mm × 50 mm × 1 mm. The operating principle of the proposed antenna and the simulation/measurement results are presented and discussed.

  19. Dual Circularly Polarized Omnidirectional Antenna with Slot Array on Coaxial Cylinder

    Directory of Open Access Journals (Sweden)

    Bin Zhou

    2015-01-01

    Full Text Available A dual circularly polarized (CP omnidirectional antenna based on slot array in coaxial cylinder structure is presented in this paper. It is constructed by perpendicular slot pairs around and along the axis of the coaxial cylinder to realize the omnidirectional CP property, and two ports are assigned in its two sides as left hand circularly polarized (LHCP port and right hand circularly polarized (RHCP port, respectively. The proposed antenna achieves a bandwidth of 16.4% ranging from 5.05 to 5.95 GHz with an isolation higher than 15 dB between the two CP ports, and the return loss (RL is higher than 10 dB within the bandwidth in both of the two ports. From the measured results, the average axial ratio (AR of the proposed antenna in omnidirectional plane is lower than 1.5 dB.

  20. CIRCULARLY POLARIZED SLOT ANTENNA WITH COMPACT SIZE FOR WLAN/WIMAX APPLICATION

    Directory of Open Access Journals (Sweden)

    Azim Rezaei Motlagh

    2014-01-01

    Full Text Available In this letter a circle patch that have two slots in ground and patch is presented. The antenna is operated in WLAN/WiMAX at 4.7~6 GHz. The 3dB axial ratio bandwidth is 0.5GHz at 5.3~5.8GHz. Comparison results between measured and simulated of antenna are acceptable.

  1. Circularly Polarized Slotted Microstrip Patch Antenna with Finite Ground Plane

    Directory of Open Access Journals (Sweden)

    Sanyog Rawat

    2012-12-01

    Full Text Available In this paper a new geometry of circularly polarized patch antenna is proposed with improved bandwidth. The radiation performance of proposed patch antenna is investigated using IE3D simulation software and its performance is compared with that of conventional rectangular patch antenna. The simulated return loss, axial ratio and impedance with frequency for the proposed antenna are reported in this paper. It is shown that by selecting suitable ground-plane dimensions, air gap and location of the slots, the impedance bandwidth can be enhanced upto 10.15% as compared to conventional rectangular patch (4.24% with an axial ratio bandwidth of 4.05%.

  2. Tunable inkjet-printed slotted waveguide antenna on a ferrite substrate

    KAUST Repository

    Nafe, Ahmed; Farooqui, Muhammad; Shamim, Atif

    2015-01-01

    In this work an inkjet-printed frequency-tunable slotted waveguide antenna on a ferrite substrate is reported. Unlike the typical substrate integrated waveguide approach with via holes, a true 3D rectangular waveguide is realized by inkjet-printing

  3. Broadband, Low Sidelobe, Zero Height, Slotted Circular Disk Antenna

    African Journals Online (AJOL)

    A rigorous mathematical theory for a rotationally symmetrical slotted circular disk antenna was developed. The theory applies the principle of "Gradient Invariance" of electromagnetic fields to determine the field components that are unique and single valued at any point in space. To detemine the radiation characteristics of ...

  4. Single-nanoparticle detection with slot-mode photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-29

    Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

  5. Different optical properties in different periodic slot cavity geometrical morphologies

    Science.gov (United States)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

    2016-09-01

    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  6. CPW-fed Circularly Polarized Slot Antenna with Small Gap and Stick-shaped Shorted Strip for UHF FRID Readers

    Science.gov (United States)

    Pan, Chien-Yuan; Su, Chum-Chieh; Yang, Wei-Lin

    2018-04-01

    A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894-1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910-970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.

  7. An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

    KAUST Repository

    Hussain, Rifaqat; Sharawi, Mohammad S.; Shamim, Atif

    2017-01-01

    This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

  8. An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

    KAUST Repository

    Hussain, Rifaqat

    2017-12-08

    This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

  9. A Novel Structure and Design Optimization of Compact Spline-Parameterized UWB Slot Antenna

    Directory of Open Access Journals (Sweden)

    Koziel Slawomir

    2016-12-01

    Full Text Available In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM simulation model of the structure that includes (for reliability an SMA connector. Another problem is a large number of geometry parameters (nineteen. For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.

  10. Spiral Slotted Microstrip Antenna Design for 700 MHz Band Application

    Directory of Open Access Journals (Sweden)

    Ricardo Meneses González

    2016-01-01

    Full Text Available This work describes the design and implementation of spiral slotted microstrip antenna. Recently, just like other countries, in Mexico, terrestrial digital television has been implemented (analogic shutdown; as a consequence, the 700 MHz UFH Band (698–806 MHz has been opened to new telecommunications services, particularly wireless mobile communication. This technological advance represents a radio mobile antenna design challenge because it is necessary to design an antenna whose dimensions must be small enough, which satisfies gain, resonance frequency, and bandwidth requirements and is of low cost.

  11. UHF coplanar-slot antenna for aircraft-to-satellite data communications

    Science.gov (United States)

    Myhre, R. W.

    1979-01-01

    The initiative for starting the Aircraft-to-Satellite Data Relay (ASDAR) Program came from a recognition that much of the world's weather originates in the data sparse area of the tropics which are primarily ocean. The ASDAR system consists of (1) a data acquisition and control unit to acquire, store and format these data; (2) a clock to time the data sampling and transmission periods; and (3) a transmitter and low-profile upper hemisphere coverage antenna to relay the formatted data via satellite to the National Weather Service ground stations, as shown schematically. The low-profile antenna is a conformal antenna based on the coplanar-slot approach. The antenna is circular polarized and has an on-axis gain of nearly 2.5 dB and a HPBW greater than 90 deg. The discussion covers antenna design, radiation characteristics, flight testing, and system performance.

  12. A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

    Directory of Open Access Journals (Sweden)

    Biao Li

    2016-01-01

    Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

  13. Artificial Material Integrated Ultra-wideband Tapered Slot Antenna for Gain Enhancement with Band Notch Characteristics

    Directory of Open Access Journals (Sweden)

    R. Singha

    2018-04-01

    Full Text Available The gain of the ultra-wideband tapered slot antenna (TSA is enhanced by using broadband artificial material with band notch characteristics. The proposed artificial material unit cell is designed by fabricating non-resonant three S-shaped parallel metallic line on single side of the dielectric substrate which provides a longer current path compared to the parallel-line structure. The proposed S-shaped structure is printed on the top side of the tapered slot antenna in the extended substrate periodically. The effective refractive index of the artificial material is lower than antenna substrate and phase velocity in the region of artificial material is much higher than the other region. Therefore, the proposed artificial material acts like a beam focusing lens. The band notch at 5.5 GHz is achieved by creating a split ring resonator (SRR slot near the balun. The basic and artificial material loaded TSAs are fabricated and the measurement results show that the gain of the basic antenna has been increased by 1.6 dBi. At the same time, the proposed antenna achieves a VSWR below 2 from 3 to 11 GHz except at 5.5 GHz with a notch band from 5.1 to 5.8 GHz for band rejection of wireless local area network (WLAN application.

  14. Finite difference time domain modeling of spiral antennas

    Science.gov (United States)

    Penney, Christopher W.; Beggs, John H.; Luebbers, Raymond J.

    1992-01-01

    The objectives outlined in the original proposal for this project were to create a well-documented computer analysis model based on the finite-difference, time-domain (FDTD) method that would be capable of computing antenna impedance, far-zone radiation patterns, and radar cross-section (RCS). The ability to model a variety of penetrable materials in addition to conductors is also desired. The spiral antennas under study by this project meet these requirements since they are constructed of slots cut into conducting surfaces which are backed by dielectric materials.

  15. Microrectenna: A Terahertz Antenna and Rectifier on a Chip

    Science.gov (United States)

    Siegel, Peter

    2007-01-01

    A microrectenna that would operate at a frequency of 2.5 THz has been designed and partially fabricated. The circuit is intended to be a prototype of an extremely compact device that could be used to convert radio-beamed power to DC to drive microdevices (see Figure 1). The microrectenna (see Figure 2) circuit consists of an antenna, a diode rectifier and a DC output port. The antenna consists of a twin slot array in a conducting ground plane (denoted the antenna ground plane) over an enclosed quarter-wavelength-thick resonant cavity (denoted the reflecting ground plane). The circuit also contains a planar high-frequency low-parasitic Schottky-barrier diode, a low-impedance microstrip transmission line, capacitors, and contact beam leads. The entire 3-D circuit is fabricated monolithically from a single GaAs wafer. The resonant cavity renders the slot radiation pattern unidirectional with a half-power beam width of about 65. A unique metal mesh on the rear of the wafer forms the backplate for the cavity but allows the GaAs to be wet etched from the rear surface of the twin slot antennas and ground plane. The beam leads protrude past the edge of the chip and are used both to mount the microrectenna and to make the DC electrical connection with external circuitry. The antenna ground plane and the components on top of it are formed on a 2- m thick GaAs membrane that is grown in the initial wafer MBE (molecular beam epitaxy) process. The side walls of the antenna cavity are not metal coated and, hence, would cause some loss of power; however, the relatively high permittivity (epsilon=13) of the GaAs keeps the cavity modes well confined, without the usual surface-wave losses associated with thick dielectric substrates. The Schottky-barrier diode has the usual submicron dimensions associated with THz operation and is formed in a mesa process above the antenna ground plane. The diode is connected at the midpoint of a microstrip transmission line, which is formed on 1- m

  16. Linearly tapered slot antenna circular array for mobile communications

    Science.gov (United States)

    Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

    1993-01-01

    The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

  17. Enhancement of acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities by utilizing surface acoustic waves

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Tian-Xue [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Wang, Yue-Sheng, E-mail: yswang@bjtu.edu.cn [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Chuanzeng [Department of Civil Engineering, University of Siegen, D-57068 Siegen (Germany)

    2017-01-30

    A phoxonic crystal is a periodically patterned material that can simultaneously localize optical and acoustic modes. The acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities is investigated numerically. The photons can be well confined in the slot owing to the large electric field discontinuity at the air/dielectric interfaces. Besides, the surface acoustic modes lead to the localization of the phonons near the air-slot. The high overlap of the photonic and phononic cavity modes near the slot results in a significant enhancement of the moving interface effect, and thus strengthens the total acousto-optical interaction. The results of two cavities with different slot widths show that the coupling strength is dependent on the slot width. It is expected to achieve a strong acousto-optical/optomechanical coupling in air-slot phoxonic crystal structures by utilizing surface acoustic modes. - Highlights: • Two-dimensional air-slot phoxonic crystal cavities which can confine simultaneously optical and acoustic waves are proposed. • The acoustic and optical waves are highly confined near/in the air-slot. • The high overlap of the photonic and phononic cavity modes significantly enhances the moving interface effect. • Different factors which affect the acousto-optical coupling are discussed.

  18. Coplanar Waveguide Fed Compact Wide Circular-Slotted Antenna for Wi-Fi/WiMAX Applications

    Directory of Open Access Journals (Sweden)

    M. Samsuzzaman

    2014-01-01

    Full Text Available A coplanar waveguide (CPW fed printing and wide circular slotted, dual band antenna for Wi-Fi/WiMAX applications are presented. The antenna mainly encompasses a ground with a wide circular slot in the centre, a rectangular feeding strip, and two pairs of symmetric planar inverted L (SPIL strips connecting with the slotted ground. The tuning effects of the rectangular patch, ground size, and SPIL strips to the resonance and matching condition are examined by HFSS and the prototype is fabricated and measured. The simulation and experimental results show that the antenna has an impedance bandwidth with −10 dB reflection coefficients 600 MHz (3.26–3.86 GHz, lower band and 1040 MHz (5.02–6.26 GHz, upper band, which can cover both the Wi-Fi 5.2/5.5/5.8 GHz and WiMAX 3.3/3.5/3.7/5.8 GHz bands. Moreover, a stable omnidirectional radiation pattern and average peak gain for lower band 3.23 dB and upper band 5.93 dB have been achieved, respectively.

  19. A U-Shaped Slot UWB Antenna with Flexible and Wide Tunable Dual Notch Band

    Directory of Open Access Journals (Sweden)

    Zhang Zhongmin

    2016-01-01

    Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with flexible and wide tunable dual bandnotched characteristics is proposed in this paper. The dual band-notched function is achieved by using an U-shaped slot inserted into the ellipse radiation patch and by using an elliptic parasitic slit placed near the ground plane. The wide tunable band-notched characteristic is implemented by adjusting the length of U-shaped slot and by adjusting the length of ellipse parasitic slit. The design aims to achieve wide reconfigurable band-notched features on the UWB antenna. The simulated results indicate that the proposed antenna has a wide bandwidth (VSWR under 2 from 2.9GHz to 12.6GHz with fractional bandwidth of 125%, and has a wide tunable notch band center frequency from 4.5GHz to 12.4GHz.

  20. Nano-polarization-converter based on magnetic plasmon resonance excitation in an L-shaped slot antenna.

    Science.gov (United States)

    Yang, Jing; Zhang, Jiasen

    2013-04-08

    We propose a nano-polarization-converter made of a resonant L-shaped slot antenna in a gold film and study its optical properties using the finite-difference time-domain method. Phase retardation between the fast and slow axes of the nano-polarization-converter originates from the simultaneous excitation of both single-surface first-order magnetic plasmon resonance mode and second-order magnetic plasmon resonance mode at the working wavelength. By adjusting the size of the slot antenna, which is still much smaller than the wavelength, the working wavelength can be tuned within a large wavelength range.

  1. Dual Band a-Si:H Solar-Slot Antenna for 2.4/5.2GHz WLAN Applications

    Directory of Open Access Journals (Sweden)

    S. V. Shynu

    2009-12-01

    Full Text Available A simple and compact design of solar-slot antenna for dual band 2.4/5.2GHz wireless local area networks (WLAN applications is proposed. The design employs amorphous silicon (a-Si:H solar cells in polyimide substrate with an embedded twin strip slot structure to generate dual resonant frequencies. A T-shaped microstripline feed is used to excite the twin slot in the a-Si:H solar cell. The measured impedance bandwidths for the proposed solar antenna are 25.9% (642 MHz centered at 2.482 GHz and 8.2% (420 MHz centered at 5.098 GHz. The measured gain at 2.4 and 5.2 GHz are 3.1 dBi and 2.1 dBi respectively.

  2. Tunable inkjet-printed slotted waveguide antenna on a ferrite substrate

    KAUST Repository

    Nafe, Ahmed

    2015-04-13

    In this work an inkjet-printed frequency-tunable slotted waveguide antenna on a ferrite substrate is reported. Unlike the typical substrate integrated waveguide approach with via holes, a true 3D rectangular waveguide is realized by inkjet-printing of nano-particle based conductive ink on the broad faces as well as on sides of the substrate. The operating frequency of the antenna can be tuned by applying a variable static bias magnetic field that controls the permeability of the host ferrite substrate. The antenna operates about a center frequency of approximately 14 GHz with an instantaneous impedance bandwidth of 75 MHz. A fabricated prototype has demonstrated a tuning range of 10% (1.5 GHz) using an applied bias magnetic field of 3 kOe yielding it especially attractive for tunable and reconfigurable yet low cost microwave systems.

  3. Radio-Frequency design of a Lower Hybrid Slotted Waveguide Antenna.

    Czech Academy of Sciences Publication Activity Database

    Helou, W.; Goniche, M.; Hillairet, J.; Žáček, František; Achard, J.; Adámek, Jiří; Bogár, Ondrej; Mollard, P.; Pascal, J.-Y.; Poli, S.; Šesták, David; Volpe, R.; Zajac, Jaromír

    2017-01-01

    Roč. 123, November (2017), s. 223-227 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] Institutional support: RVO:61389021 Keywords : Lower Hybrid Current Drive * Slotted Waveguide Antenna * Phased arrays Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016 https://www.sciencedirect.com/science/article/pii/S0920379617304076

  4. Circularly polarized antennas

    CERN Document Server

    Gao, Steven; Zhu, Fuguo

    2013-01-01

    This book presents a comprehensive insight into the design techniques for different types of CP antenna elements and arrays In this book, the authors address a broad range of topics on circularly polarized (CP) antennas. Firstly, it introduces to the reader basic principles, design techniques and characteristics of various types of CP antennas, such as CP patch antennas, CP helix antennas, quadrifilar helix antennas (QHA), printed quadrifilar helix antennas (PQHA), spiral antenna, CP slot antennas, CP dielectric resonator antennas, loop antennas, crossed dipoles, monopoles and CP horns. Adva

  5. Wideband Tunable PIFA Antenna with Loaded Slot Structure for Mobile Handset and LTE Applications

    Directory of Open Access Journals (Sweden)

    I. Elfergani

    2014-04-01

    Full Text Available A compact planar inverted F antenna (PIFA with a tunable frequency response is presented. Tuning of the resonant frequency is realized by loading a varactor on an embedded slot of the proposed antenna structure without further optimizing other antenna geometry parameters. The antenna exhibits a wide frequency range from 1570 to 2600 MHz with a good impedance matching (S11 ≤-10 dB covering the GPS, PCS, DCS, UMTS, WLAN and LTE systems. To validate the theoretical model and design concept, the antenna prototype was fabricated and measured. The compact size of the antenna is 15mm × 8mm × 3mm, which makes this antenna a good candidate for mobile handset and wireless communication applications.

  6. Band structures in two-dimensional phononic crystals with periodic Jerusalem cross slot

    Science.gov (United States)

    Li, Yinggang; Chen, Tianning; Wang, Xiaopeng; Yu, Kunpeng; Song, Ruifang

    2015-01-01

    In this paper, a novel two-dimensional phononic crystal composed of periodic Jerusalem cross slot in air matrix with a square lattice is presented. The dispersion relations and the transmission coefficient spectra are calculated by using the finite element method based on the Bloch theorem. The formation mechanisms of the band gaps are analyzed based on the acoustic mode analysis. Numerical results show that the proposed phononic crystal structure can yield large band gaps in the low-frequency range. The formation mechanism of opening the acoustic band gaps is mainly attributed to the resonance modes of the cavities inside the Jerusalem cross slot structure. Furthermore, the effects of the geometrical parameters on the band gaps are further explored numerically. Results show that the band gaps can be modulated in an extremely large frequency range by the geometry parameters such as the slot length and width. These properties of acoustic waves in the proposed phononic crystals can potentially be applied to optimize band gaps and generate low-frequency filters and waveguides.

  7. Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

    Science.gov (United States)

    Lee, Dukhyung; Kim, Dai-Sik

    2016-01-01

    We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

  8. Wearable Passive E-Textile UHF RFID Tag Based on a Slotted Patch Antenna with Sewn Ground and Microchip Interconnections

    Directory of Open Access Journals (Sweden)

    Johanna Virkki

    2017-01-01

    Full Text Available We present a wearable passive UHF RFID tag based on a slotted patch antenna comprising only textile materials (e-textile, textile substrate, and conductive yearn. As a novel manufacturing approach, we realize the patch-to-ground and antenna-to-IC interfaces using only conductive thread and a sewing machine. We outline the electromagnetic optimization of the antenna for body-worn operation through simulations and present a performance comparison between the e-textile tag and a tag produced using regular electronics materials and methods. The measured results show that the textile tag achieves the electrical performance required in practical applications and that the slotted patch type antenna provides stable electromagnetic performance in different body-worn configurations.

  9. Harmonic Suppressed Slot Antennas Using Rectangular/Circular Defected Ground Structures

    Directory of Open Access Journals (Sweden)

    Mohammad Saeid Ghaffarian

    2012-01-01

    Full Text Available Two wide rectangle-shaped microstrip-fed 2.6-GHz slot antennas using defected ground structures (DGSs with a low design complexity are proposed to achieve wideband harmonic suppression. To accomplish this, two rectangular DGSs (RDGSs in the first antenna and two circular DGSs (CDGSs in the second one with various dimensions are etched into the ground plane, which could have a wideband-stop characteristic. Simulated and measured reflection coefficients indicate that the two proposed structures effectively suppress the second and third harmonics up to 23 dB between 3.5 and 10.5 GHz with a maximum ripple of 2.4 dB. In addition, the radiation patterns and peak gains of the antennas can be suppressed at least 17 dB and 7.1 dBi, respectively, at the third harmonic frequency of 7.86 GHz.

  10. Low-loss tunable 1D ITO-slot photonic crystal nanobeam cavity

    Science.gov (United States)

    Amin, Rubab; Tahersima, Mohammad H.; Ma, Zhizhen; Suer, Can; Liu, Ke; Dalir, Hamed; Sorger, Volker J.

    2018-05-01

    Tunable optical material properties enable novel applications in both versatile metamaterials and photonic components including optical sources and modulators. Transparent conductive oxides (TCOs) are able to highly tune their optical properties with applied bias via altering their free carrier concentration and hence plasma dispersion. The TCO material indium tin oxide (ITO) exhibits unity-strong index change and epsilon-near-zero behavior. However, with such tuning the corresponding high optical losses, originating from the fundamental Kramers–Kronig relations, result in low cavity finesse. However, achieving efficient tuning in ITO-cavities without using light–matter interaction enhancement techniques such as polaritonic modes, which are inherently lossy, is a challenge. Here we discuss a novel one-dimensional photonic crystal nanobeam cavity to deliver a cavity system offering a wide range of resonance tuning range, while preserving physical compact footprints. We show that a vertical silicon-slot waveguide incorporating an actively gated-ITO layer delivers ∼3.4 nm of tuning. By deploying distributed feedback, we are able to keep the Q-factor moderately high with tuning. Combining this with the sub-diffraction limited mode volume (0.1 (λ/2n)3) from the photonic (non-plasmonic) slot waveguide, facilitates a high Purcell factor exceeding 1000. This strong light–matter-interaction shows that reducing the mode volume of a cavity outweighs reducing the losses in diffraction limited modal cavities such as those from bulk Si3N4. These tunable cavities enable future modulators and optical sources such as tunable lasers.

  11. Pulsed electromagnetic field radiation from a narrow slot antenna with a dielectric layer

    NARCIS (Netherlands)

    Štumpf, M.; De Hoop, A.T.; Lager, I.E.

    2010-01-01

    Analytic time domain expressions are derived for the pulsed electromagnetic field radiated by a narrow slot antenna with a dielectric layer in a two?dimensional model configuration. In any finite time window of observation, exact pulse shapes for the propagated, reflected, and refracted wave

  12. Co-simulation of a complete rectenna with a circular slot loop antenna in CPW technology

    Science.gov (United States)

    Rivière, Jérôme; Douyère, Alexandre; Cazour, Jonathan; Alicalapa, Frédéric; Luk, Jean-Daniel Lan Sun

    2017-05-01

    This study starts with the design of a planar and compact CPW antenna fabricated on Arlon AD1000 substrate, ɛr=10.35. The antenna is a coplanar waveguide (CPW) fed circular slot loop antenna matched to the standard impedance 50 Ω by two stubs. The goal is to implement this antenna with a CPW RF/DC rectifier to build an optimized low power level rectenna. The rectenna design is restricted to allow easy and fast fabrication of an array with a high reproducibility. The full rectenna is simulated and achieves 10% effciency at -20 dBm.

  13. Two-Element Tapered Slot Antenna Array for Terahertz Resonant Tunneling Diode Oscillators

    Directory of Open Access Journals (Sweden)

    Jianxiong Li

    2014-01-01

    Full Text Available Two-element tapered slot antenna (TSA array for terahertz (THz resonant tunneling diode (RTD oscillators is proposed in this paper. The proposed TSA array has the advantages of both the high directivity and high gain at the horizontal direction and hence can facilitate the horizontal communication between the RTD oscillators and other integrated circuit chips. A MIM (metal-insulator-metal stub with a T-shaped slot is used to reduce the mutual coupling between the TSA elements. The validity and feasibility of the proposed TSA array have been simulated and analyzed by the ANSYS/ANSOFT’s High Frequency Structure Simulator (HFSS. Detailed modeling approaches and theoretical analysis of the proposed TSA array have been fully addressed. The simulation results show that the mutual coupling between the TSA elements is reduced below −40 dB. Furthermore, at 500 GHz, the directivity, the gain, and the half power beam width (HPBW at the E-plane of the proposed TSA array are 12.18 dB, 13.09 dB, and 61°, respectively. The proposed analytical method and achieved performance are very promising for the antenna array integrated with the RTD oscillators at the THz frequency and could pave the way to the design of the THz antenna array for the RTD oscillators.

  14. A Dual Band Slotted Patch Antenna on Dielectric Material Substrate

    Directory of Open Access Journals (Sweden)

    M. Habib Ullah

    2014-01-01

    Full Text Available A low profile, compact dual band slotted patch antenna has been designed using finite element method-based high frequency full-wave electromagnetic simulator. The proposed antenna fabricated using LPKF printed circuit board (PCB fabrication machine on fiberglass reinforced epoxy polymer resin material substrate and the performance of the prototype has been measured in a standard far-field anechoic measurement chamber. The measured impedance bandwidths of (reflection coefficient <-10 dB 12.26% (14.3–16.2 GHZ, 8.24% (17.4–18.9 GHz, and 3.08% (19.2–19.8 have been achieved through the proposed antenna prototype. 5.9 dBi, 3.37 dBi, and 3.32 dBi peak gains have been measured and simulated radiation efficiencies of 80.3%, 81.9%, and 82.5% have been achieved at three resonant frequencies of 15.15 GHz, 18.2 GHz, and 19.5 GHz, respectively. Minimum gain variation, symmetric, and almost steady measured radiation pattern shows that the proposed antenna is suitable for Ku and K band satellite applications.

  15. Broadband Circularly Polarized Slot Antenna Loaded by a Multiple-Circular-Sector Patch.

    Science.gov (United States)

    Trinh-Van, Son; Yang, Youngoo; Lee, Kang-Yoon; Hwang, Keum Cheol

    2018-05-15

    In this paper, a microstrip-fed broadband circularly polarized (CP) slot antenna is presented. CP operation can be attained simply by embedding an S-shaped strip. By loading with a multiple-circular-sector patch, which consists of 12 circular-sector patches with identical central angles of 30° and different radii, the 3 dB axial ratio (AR) bandwidth is significantly broadened. To validate the performance of the proposed antenna, an antenna prototype is fabricated and tested. The fabricated antenna is 54 mm × 54 mm × 0.8 mm in size. The measured -10 dB reflection and 3 dB AR bandwidths are 81.06% (1.68⁻3.97 GHz) and 70.55% (1.89⁻3.95 GHz), respectively. Within the 3 dB AR bandwidth, the measured peak gain is 3.81 dBic. Reasonable agreement is also obtained between the measured and simulated results.

  16. Electromagnetic scattering and radiation from microstrip patch antennas and spirals residing in a cavity

    Science.gov (United States)

    Volakis, J. L.; Gong, J.; Alexanian, A.; Woo, A.

    1992-01-01

    A new hybrid method is presented for the analysis of the scattering and radiation by conformal antennas and arrays comprised of circular or rectangular elements. In addition, calculations for cavity-backed spiral antennas are given. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at O(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of large-size structures with remarkable efficiency. In this report, we describe the method's formulation and implementation for circular and rectangular patch antennas in different superstrate and substrate configurations which may also include the presence of lumped loads and resistive sheets/cards. Also, various modelling approaches are investigated and implemented for characterizing a variety of feed structures to permit the computation of the input impedance and radiation pattern. Many computational examples for rectangular and circular patch configurations are presented which demonstrate the method's versatility, modeling capability and accuracy.

  17. CIRCULARLY POLARIZED SLOTTED APERTURE ANTENNA WITH COPLANAR WAVEGUIDE FED FOR BROADBAND APPLICATIONS

    Directory of Open Access Journals (Sweden)

    B. T. P. MADHAV

    2016-02-01

    Full Text Available Coplanar waveguide fed circularly polarized microstrip patch antenna performance evaluation is presented in this paper. The broadband characteristics are attained by placing open end slot at the lower side of the antenna. The proposed design has the return loss of less than -10dB and VSWR<2 in the desired band of operation. A gain of 3dB to 4dB is attained in the desired band with good radiation characteristics and a suitable axial ratio of less than 3 dB is attained in the prescribed band of operation. Proposed antenna is fabricated on the FR4 substrate with dielectric constant of 4.4. Parametric analysis with change in substrate permittivity also performed and the optimized dimensions are presented in this work.

  18. A design procedure for a slotted waveguide with probe-fed slots radiating into plasma

    International Nuclear Information System (INIS)

    Colborn, J.A.

    1989-11-01

    A design procedure is developed for slotted-waveguide antennas with probe-fed slots. Radiation into a gyrotropic, plane-stratified medium is considered, nonzero waveguide wall thickness is assumed, and noncosinusoidal slot fields and arbitrary slot length up to about one free-space wavelength are allowed. External mutual coupling is taken into account by matching the tangential fields at the antenna surface. The particular case of longitudinal slots in the broad face of rectangular guide is analyzed. The motivation for this work is the design of such radiators for plasma heating and current-drive on thermonuclear fusion experiments, but some of the analysis is applicable to the probeless slotted waveguide used for avionics and communications. 20 refs., 5 figs

  19. Compact U-Slotted Antenna for Broadband Radar Applications

    Directory of Open Access Journals (Sweden)

    S. Costanzo

    2013-01-01

    Full Text Available The original U-shaped patch antenna is properly modified in this work to provide a compact and broadband antenna configuration with reduced cross-polar effects, well suitable for modern radar applications. The proposed antenna layout is applied to design, realize, and test two different prototypes working at P-band and C-band, typically adopted for ground-penetrating radar. The experimental results successfully demonstrate a large operating bandwidth between 15% and 20%, a significant reduction of size (about half of the standard configuration, and a low cross-polarization level within the operating frequency range.

  20. Dual-polarized feed antenna apparatus and method of use

    Science.gov (United States)

    Sarehraz, Mohammed (Inventor); Buckle, Kenneth A. (Inventor); Stefanakos, Elias (Inventor); Weller, Thomas (Inventor); Goswami, D. Yogi (Inventor)

    2009-01-01

    An antenna apparatus and method for the interception of randomly polarized electromagnetic waves utilizing a dual polarized antenna which is excited through a cross-slot aperture using two well-isolated orthogonal feeds.

  1. Ultra-Wideband Printed Slot Radiators with Controllable Frequency Characteristics

    Directory of Open Access Journals (Sweden)

    S. L. Chernyshev

    2015-01-01

    Full Text Available We have studied the possibility of creating ultra-wideband (UWB antennas with controlled frequency response of matching based on the printed slot antenna Vivaldi by introducing controlled resonators directly into the structure of the radiator. In the area of irregular slotline there are printed switched resonators with variable capacitance (varactor model, which allow tuning the frequency characteristics for each state of switching cavities, providing bandpass and band-barrage properties of the antenna. The investigation of reconfigurable printed resonators in the system of reconfigurable resonators of a bandpass filter is conducted. The paper considers filter to provide restructuring in the band (3-9 GHz. Electrodynamic simulation of the device was carried out in the time domain using a finite integration method. A bandstop reconfigurable filter is also investigated. The filter located on the substrate opposite the slit is based on tunable L-shaped resonator that has one end connected to the short-circuitor through the board metallization; the other end remains open and is brought into the region of interaction with the slotline. Such filter provides an effective narrow-band suppression and can be easily tuned to the desired frequency channel. The combination of these two types of filters allows you to create a controlled print Vivaldi slot antenna with combined properties. The paper investigates parameters of the scattering and radiation pattern of the antenna in different modes.

  2. Problem-Matched Basis Functions for Microstrip Coupled Slot Antennas based on Transmission Line Greens Functions

    NARCIS (Netherlands)

    Bruni, S.; Llombart Juan, N.; Neto, A.; Gerini, G.; Maci, S.

    2004-01-01

    A general algorithm for the analysis of microstrip coupled leaky wave slot antennas was discussed. The method was based on the construction of physically appealing entire domain Methods of Moments (MoM) basis function that allowed a consistent reduction of the number of unknowns and of total

  3. A multiband dual-standard MIMO antenna system based on monopoles (4G) and connected slots (5G) for future smart phones

    KAUST Repository

    Ikram, M.

    2018-04-24

    In this work, a 4G/5G multiple-input multiple-output (MIMO) antenna system is presented for smart phone applications. The 4G antenna operates from 1900 to 3212 MHz and 3517 to 3712 MHz with 1312 (69%) and 195 (5.5%) MHz measured bandwidths, respectively. The 5G antenna covers 25.7–30.50 GHz band with 4.8 GHz (18.7%) measured bandwidth. The 4G MIMO antenna system is based on 4-element wideband monopoles, while the 5G one is based on 2-element linear connected arrays (LCA). Four slots are etched to improve the isolation between the 4G MIMO antenna elements and then a 4 × 1 power divider/combiner is used to excite two of these slots to act as a LCA at mm-waves. The concept of dual function ground slots is very useful to implement 4G and 5G MIMO antenna systems on the single substrate. The proposed design is fabricated on RO4350B substrate with a height of 0.76 mm and dielectric constant of 3.5. The overall size of the substrate is 115 × 65 × 0.76 mm. The integrated wideband 4G/5G antenna system is a compact, low profile, and suitable for future smart phone applications. Isolation obtained was at least 15 dB and the envelope correlation coefficient (ECC) values did not exceed 0.16 between all elements.

  4. Effect of Substrate Permittivity and Thickness on Performance of Single-Layer, Wideband, U-Slot Antennas on Microwave Substrates

    National Research Council Canada - National Science Library

    Natarajan, V; Chatterjee, D

    2004-01-01

    This paper presents effects of substrate permittivity and thickness on the performance characteristics like impedance bandwidth, radiation efficiency and gain of a single-layer, wideband, U-slot antenna...

  5. Experimental measurements of the ion cyclotron antennas' coupling and rf characteristics

    International Nuclear Information System (INIS)

    Hoffman, D.J.; Baity, F.W.; Becraft, W.R.; Caughman, J.B.O.; Owens, T.L.

    1985-01-01

    The rf coupling capabilities and characteristics of various antennas have been measured. The tested antenna configurations include the simple loop antenna operated at resonant lengths as used on Alcator-C, the cavity antenna proposed for Doublet III-D and the resonant double loop, asymmetric resonant double loop, and U-slot antennas. Models of the voltage, magnetic fields outside the structure, and current have been correlated with the measurements made on these antennas. From these measurements and from typical observations of ICRH coupling in tokamaks, we are studying power and frequency limitations on each antenna and the causes of the limitations. A comparison of the technology, performance, and power limitations of each type of antenna is presented

  6. Dielectric Covered Planar Antennas at Submillimeter Wavelengths for Terahertz Imaging

    Science.gov (United States)

    Chattopadhyay, Goutam; Gill, John J.; Skalare, Anders; Lee, Choonsup; Llombart, Nuria; Siegel, Peter H.

    2011-01-01

    Most optical systems require antennas with directive patterns. This means that the physical area of the antenna will be large in terms of the wavelength. When non-cooled systems are used, the losses of microstrip or coplanar waveguide lines impede the use of standard patch or slot antennas for a large number of elements in a phased array format. Traditionally, this problem has been solved by using silicon lenses. However, if an array of such highly directive antennas is to be used for imaging applications, the fabrication of many closely spaced lenses becomes a problem. Moreover, planar antennas are usually fed by microstrip or coplanar waveguides while the mixer or the detector elements (usually Schottky diodes) are coupled in a waveguide environment. The coupling between the antenna and the detector/ mixer can be a fabrication challenge in an imaging array at submillimeter wavelengths. Antennas excited by a waveguide (TE10) mode makes use of dielectric superlayers to increase the directivity. These antennas create a kind of Fabry- Perot cavity between the ground plane and the first layer of dielectric. In reality, the antenna operates as a leaky wave mode where a leaky wave pole propagates along the cavity while it radiates. Thanks to this pole, the directivity of a small antenna is considerably enhanced. The antenna consists of a waveguide feed, which can be coupled to a mixer or detector such as a Schottky diode via a standard probe design. The waveguide is loaded with a double-slot iris to perform an impedance match and to suppress undesired modes that can propagate on the cavity. On top of the slot there is an air cavity and on top, a small portion of a hemispherical lens. The fractional bandwidth of such antennas is around 10 percent, which is good enough for heterodyne imaging applications.The new geometry makes use of a silicon lens instead of dielectric quarter wavelength substrates. This design presents several advantages when used in the submillimeter

  7. Low Radar Cross-section and Low Cost Dipole Antenna Reflector

    Directory of Open Access Journals (Sweden)

    G. G. Machado

    2017-10-01

    Full Text Available This paper presents a method for reducing Radar CrossSection (RCS of an increased gain metal backed dipole antenna. Numerical simulations were done and compared to a laboratory experiment. The results show that when a Perfect Electrical Conductor (PEC is replaced by a Frequency Selective Surface (FSS, the antenna is still able to perform with the desired characteristics, but the RCS of the structure is greatly reduced out of band. The design of the FSS and the return loss, gain improvement, and RCS are presented for an antenna operating at 4.2GHz, and the results are compared with a conventional metal backed layout. Measurements show a good agreement with the simulations, and so the advantages on other structures from the reviewed literature are mentioned.

  8. Dual Mode Slotted Monopole Antenna

    Science.gov (United States)

    2017-01-05

    May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is directed...to connect across slot 14. [0005] In United States Patent No. 6,127,983 to Rivera and Josypenko, it has been shown that the slotted cylinder

  9. Plasmonic-cavity model for radiating nano-rod antennas

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

    In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition and the ......In this paper, we propose the analytical solution of nano-rod antennas utilizing a cylindrical harmonics expansion. By treating the metallic nano-rods as plasmonic cavities, we derive closed-form expressions for both the internal and the radiated fields, as well as the resonant condition...... and the radiation efficiency. With our theoretical model, we show that besides the plasmonic resonances, efficient radiation takes advantage of (a) rendering a large value of the rods' radius and (b) a central-fed profile, through which the radiation efficiency can reach up to 70% and even higher in a wide...... frequency band. Our theoretical expressions and conclusions are general and pave the way for engineering and further optimization of optical antenna systems and their radiation patterns....

  10. A Compact UWB Antenna with a Quarter-Wavelength Strip in a Rectangular Slot for 5.5 GHz Band Notch

    Directory of Open Access Journals (Sweden)

    Pichet Moeikham

    2013-01-01

    Full Text Available The limitation of the electromagnetic interferences (EMIs caused by UWB radiating sources into WLAN/WiMAX communication systems operating in the frequency band located around 5.5 GHz requires the adoption of appropriate design features. To this purpose, a notch filter integrated into an UWB antenna, which is able to ensure a better electrical insulation between the two mentioned communication systems with respect to that already presented by the authors Moeikham et al. (2011, is proposed in this paper. The proposed filter, consisting in a rectangular slot including a quarter-wavelength strip integrated on the lower inner edge of the UWB radiating patch, is capable of reducing the energy emission in the frequency range between 5.1 and 5.75 GHz resulting in lower EMIs with sensible electronic equipments working in this frequency band. The antenna structure has no need to be tuned after inserting the rectangle slot with a quarter-wavelength strip. The proposed antenna has potential to minimize the EMIs at a frequency range from 5.1 to 5.75 GHz. The radiation patterns are given nearly omnidirectional in plane and likely bidirectional in plane at all frequencies by the proposed antenna. Therefore, this antenna is suitable to apply for various UWB applications.

  11. Measurements of the loading impedance and field scaling of a cavity ICRF launcher for Big D

    International Nuclear Information System (INIS)

    Rettig, C.; Ryan, P.M.; Hoffman, D.J.

    1985-01-01

    Recently, a new ICRF launcher in the form of a resonant coil cavity has been proposed and analyzed using a convenient two-dimensional model and a Poisson-solver computer code. Here, a physical model of the launcher has been fabricated to test the scaling characteristics of the impedance and relative fields as a function of the physical sizing of the structure. Variable parameters include the antenna-to-plasma distance, the cavity back wall-to-plasma distance, and the antenna cross-sectional shape. Each of these parameters is varied in the interest of optimizing the radiated power for given antenna voltage and current limits. Critical design criterial will be determined from the data. The report consists of 21 viewgraphs

  12. A Broadband VHF-L Band Cavity-Backed Slot Spiral Antenna

    Science.gov (United States)

    2005-05-01

    each new frequency. When the frequency list is completed, the Flight Test Engineer will contact the Test Technician and request any necessary...immediately required elsewhere. Frequency List ; 50.05 MHz, 144.05 MHz, 432.05 MHz, 902.05 MHz, 1.29605 GHz...Repeat Completed? (Y/N) Test Completed? (Y/N) Frequency List ; 50.05 MHz, 144.05 MHz, 432.05 MHz, 902.05 MHz, 1.29605 GHz

  13. Analysis and design of broadband U-slot cut rectangular microstrip ...

    Indian Academy of Sciences (India)

    AMIT A DESHMUKH

    2017-07-15

    Jul 15, 2017 ... Abstract. Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design. U-slot cut antennas at any given frequency is not explained. In this paper, first an ...

  14. A highly directive graphene antenna embedded inside a Fabry-Perot cavity in terahertz regime

    Science.gov (United States)

    Roshanaei, Majid; Karami, Hamidreza; Dehkhoda, Parisa; Esfahani, Hamid; Dabir, Fatemeh

    2018-05-01

    In this paper, a highly directive nano-thickness graphene-based antenna is introduced in the terahertz frequency band. The antenna is a graphene patch dipole which is placed between two Bragg mirrors called Fabry-Perot cavity. Tunability of the graphene's conductivity makes it possible to excite the desired resonances of the cavity. Here, first, a single resonant antenna is introduced at 5 THz with an enhanced gain from 2.11 dBi to 12.8 dBi with a beamwidth of 22.7°. Then, a triple resonant antenna at 4.7, 5 and 5.3 THz is presented with respective gains of 7.97, 11.9 and 8.52 dBi. Finally, the effect of dimensions and number of the dielectric layers of the cavity are studied in order to further increase in directivity.

  15. Computation of the frequency response of a nonlinearly loaded antenna within a cavity

    Directory of Open Access Journals (Sweden)

    F. Gronwald

    2004-01-01

    Full Text Available We analyze a nonlinearly loaded dipole antenna which is located within a rectangular cavity and excited by an electromagnetic signal. The signal is composed from two different frequencies. In order to calculate the spectrum of the resulting electromagnetic field within the resonator we transform the antenna problem into a network problem. This requires to precisely determine the antenna impedance within the cavity. The resulting nonlinear equivalent network is solved by means of the harmonic balance technique. As a result the occurrence of low intermodulation frequencies within the spectrum is verified.

  16. A Wideband High-Gain Dual-Polarized Slot Array Patch Antenna for WiMAX Applications in 5.8 GHz

    Directory of Open Access Journals (Sweden)

    Amir Reza Dastkhosh

    2012-01-01

    Full Text Available A low-cost, easy-to-fabricate, wideband and high-gain dual-polarized array antenna employing an innovative microstrip slot patch antenna element is designed and fabricated. The design parameters of the antenna are optimized using commercial softwares (Microwave Office and Zeland IE3D to get the suitable -parameters and radiation patterns. Finally, the simulation results are compared to the experimental ones and a good agreement is demonstrated. The antenna has an approximately bandwidth of 14% (5.15–5.9 GHz which covers Worldwide Interoperability Microwave Access (WiMAX/5.8. It also has the peak gain of 26 dBi for both polarizations and high isolation between two ports over a wide bandwidth.

  17. Circularly Polarized S Band Dual Frequency Square Patch Antenna Using Glass Microfiber Reinforced PTFE Composite

    Directory of Open Access Journals (Sweden)

    M. Samsuzzaman

    2014-01-01

    Full Text Available Circularly polarized (CP dual frequency cross-shaped slotted patch antenna on 1.575 mm thick glass microfiber reinforced polytetrafluoroethylene (PTFE composite material substrate is designed and fabricated for satellite applications. Asymmetric cross-shaped slots are embedded in the middle of the square patch for CP radiation and four hexagonal slots are etched on the four sides of the square patch for desired dual frequency. Different substrate materials have been analysed to achieve the desired operating band. The experimental results show that the impedance bandwidth is approximately 30 MHz (2.16 GHz to 2.19 GHz for lower band and 40 MHz (3.29 GHz to 3.33 GHz for higher band with an average peak gain of 6.59 dBiC and 5.52 dBiC, respectively. Several optimizations are performed to obtain the values of the antenna physical parameters. Moreover, the proposed antenna possesses compactness, light weight, simplicity, low cost, and circularly polarized. It is an attractive candidate for dual band satellite antennas where lower band can be used for uplink and upper band can be used for downlink.

  18. Minimum Lens Size Supporting the Leaky-Wave Nature of Slit Dipole Antenna at Terahertz Frequency

    Directory of Open Access Journals (Sweden)

    Niamat Hussain

    2016-01-01

    Full Text Available We designed a slit dipole antenna backed by an extended hemispherical silicon lens and investigated the minimum lens size in which the slit dipole antenna works as a leaky-wave antenna. The slit dipole antenna consists of a planar feeding structure, which is a center-fed and open-ended slot line. A slit dipole antenna backed by an extended hemispherical silicon lens is investigated over a frequency range from 0.2 to 0.4 THz with the center frequency at 0.3 THz. The numerical results show that the antenna gain responses exhibited an increased level of sensitivity to the lens size and increased linearly with increasing lens radius. The lens with the radius of 1.2λo is found to be the best possible minimum lens size for a slit dipole antenna on an extended hemispherical silicon lens.

  19. Low Average Sidelobe Slot Array Antennas for Radiometer Applications

    Science.gov (United States)

    Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

    2012-01-01

    In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E

  20. Coupling slots without shunt impedance drop

    International Nuclear Information System (INIS)

    Balleyguier, P.

    1996-01-01

    It is well known that coupling slots between adjacent cells in a π-mode structure reduce shunt impedance per unit length with respect to single cell cavities. To design optimized coupling slots, one has to answer the following question: for a given coupling factor, what shape, dimension, position and number of slots lead to the lowest shunt impedance drop? A numerical study using the 3D code MAFIA has been carried out. The aim was to design the 352 MHz cavities for the high intensity proton accelerator of the TRISPAL project. The result is an unexpected set of four 'petal' slots. Such slots should lead to a quasi-negligible drop in shunt impedance: about -1% on average, for particle velocity from 0.4 c to 0.8 c. (author)

  1. Wireless passive polymer-derived SiCN ceramic sensor with integrated resonator/antenna

    Science.gov (United States)

    Li, Yan; Yu, Yuxi; San, Haisheng; Wang, Yansong; An, Linan

    2013-10-01

    This paper presents a passive wireless polymer-derived silicon carbonitride (SiCN) ceramic sensor based on cavity radio frequency resonator together with integrated slot antenna. The effect of the cavity sensor dimensions on the Q-factor and resonant frequency is investigated by numerical simulation. A sensor with optimal dimensions is designed and fabricated. It is demonstrated that the sensor signal can be wirelessly detected at distances up to 20 mm. Given the high-temperature stability of the SiCN, the sensor is very promising for high-temperature wireless sensing applications.

  2. An improved broadband E patch microstrip antenna for wireless communications

    Science.gov (United States)

    Bzeih, Amer; Chahine, Soubhi Abou; Kabalan, Karim Y.; El-Hajj, Ali; Chehab, Ali

    2007-12-01

    A broadband probe-fed microstrip antenna with E-shaped patch on a single-layer air substrate is investigated. Bandwidth enhancement of the antenna is achieved by inserting two parallel slots into its radiating patch. The effects of the antenna parameters are analyzed, and their optimal values for broadband operation are obtained. The design parameters are formulated as a function of the center frequency, and the empirical equations are validated by simulation. A 51.5% enhanced E patch antenna for modern wireless communications (Personal Communications Service, Digital Cellular System, Universal Mobile Telecommunications System, Wireless Local Area Network 802.11 b/g, and Bluetooth) is designed, simulated, fabricated, and measured. A comparison between simulated and measured results is presented, and it showed satisfactory agreement. Moreover, the effect of incorporating more parallel slots into the radiating patch is investigated. The antenna is designed and simulated for different scenarios (four slots, six slots, and eight slots), where a bandwidth of 57% is achieved in the eight-slot design.

  3. Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications.

    Science.gov (United States)

    Dong, Jian; Li, Qianqian; Deng, Lianwen

    2017-02-10

    Ultrawideband (UWB) antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT). A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 x 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5-6 GHz for rejecting the Wireless Local Area Network (WLAN) is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX) is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR applications.

  4. Investigation of a slot nanoantenna in optical frequency range

    Science.gov (United States)

    Dinesh kumar, V.; Asakawa, Kiyoshi

    2009-11-01

    Following the analogy of radio frequency slot antenna and its complementary dipole, we propose the implementation of a slot nanoantenna (SNA) in the optical frequency range. Using finite-difference time-domain (FDTD) method, we investigate the electromagnetic (EM) properties of a SNA formed in a thin gold film and compare the results with the properties of a gold dipole nanoantenna (DNA) of the same dimension as the slot. It is found that the response of the SNA is very similar to the DNA, like their counterparts in the radio frequency (RF) range. The SNA can enhance the near field intensity of incident field which strongly depends on its feedgap dimension. The resonance of the SNA is influenced by its slot length; for the increasing slot length, resonant frequency decreases whereas the sharpness of resonance increases. Besides, the resonance of the SNA is found sensitive to the thickness of metal film, when the latter is smaller than the skin depth. The effect of polarization of incident field on the EM response of the SNA was examined; the field enhancement is optimum when polarization is parallel to the feedgap. Finally, we calculate the radiation patterns of the DNA and SNA and compare them with those of the RF dipole antenna. The radiation pattern of the SNA is found to be independent of its slot length when excited at resonant frequency. To the best of our knowledge, this is the first study on a slot antenna in the optical frequency.

  5. Fan-shaped antennas: Realization of wideband characteristics and generation of stop bands

    Science.gov (United States)

    Nakano, H.; Morishita, K.; Iitsuka, Y.; Mimaki, H.; Yoshida, T.; Yamauchi, J.

    2008-08-01

    This paper presents four fan-shaped antennas: U.S.-FAN, CROSS-FAN, CROSS-FAN-W, and CROSS-FAN-S. Each of these antennas stands upright above a ground plane, and has edges expressed by an exponential function and a circle function. The four antennas are investigated using frequencies from 1.5 GHz to 11 GHz. The CROSS-FAN is found to have a lower VSWR over a wide frequency band compared to the U.S.-FAN. The CROSS-FAN-W and CROSS-FAN-S are modified versions of the CROSS-FAN, each designed to have a stop band (a high VSWR frequency range) for interference cancellation. The stop band for the CROSS-FAN-W is controlled by a wire (total length 4Lwire) that connects the fan-shaped elements. The center frequency of the stop band fstop is close to the frequency corresponding to a wire segment length Lwire of half the wavelength. It is also found that the stop band in the CROSS-FAN-S can be controlled by four slots, one cut into each of the fan-shaped elements. The center frequency of the stop band fstop is close to the frequency corresponding to a slot length Lslot of one-quarter of the wavelength. Experimental work is performed to confirm the theoretical results, using the CROSS-FAN-S.

  6. Wearable Shell Antenna for 2.4 GHz Hearing Instruments

    DEFF Research Database (Denmark)

    Ruaro, Andrea; Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2016-01-01

    A novel concept for an electrically-small on-body antenna targeted for 2.4 GHz ISM band custom in-the-ear (ITE) hearing instrument (HI) applications is introduced. The antenna is based upon a cavity-backed design in order to take advantage of the maximum volume available in the ear while providin...

  7. UV plasmonic enhancement through three dimensional nano-cavity antenna array in aluminum

    Science.gov (United States)

    Mao, Jieying; Stevenson, Peter; Montanaric, Danielle; Wang, Yunshan; Shumaker-Parry, Jennifer S.; Harris, Joel M.; Blair, Steve

    2017-08-01

    Metallic nanostructure can enhance fluorescence through excited surface plasmons which increase the local field as well as improve its quantum efficiency. When coupling to cavity resonance with proper gap dimension, gap hot spots can be generated to interact with fluorescence at their excitation/emission region in UV. A 3D nano-cavity antenna array in Aluminum has been conducted to generate local hot spot resonant at fluorescence emission resonance. Giant field enhancement has been achieved through coupling fundamental resonance modes of nanocavity into surface plasmons polaritons (SPPs). In this work, two distinct plasmonic structure of 3D resonant cavity nanoantenna has been studied and its plasmonic response has been scaled down to the UV regime through finite-difference-time-domain (FDTD) method. Two different strategies for antenna fabrication will be conducted to obtain D-coupled Dots-on-Pillar Antenna array (D2PA) through Focus Ion Beam (FIB) and Cap- Hole Pair Antenna array (CHPA) through nanosphere template lithography (NTL). With proper optimization of the structures, D2PA and CHPA square array with 280nm pitch have achieved distinct enhancement at fluorophore emission wavelength 350nm and excitation wavelength 280nm simultaneously. Maximum field enhancement can reach 20 and 65 fold in the gap of D2PA and CHPA when light incident from substrate, which is expected to greatly enhance fluorescent quantum efficiency that will be confirmed in fluorescence lifetime measurement.

  8. Improvement of antenna decoupling in radar systems

    Science.gov (United States)

    Anchidin, Liliana; Topor, Raluca; Tamas, Razvan D.; Dumitrascu, Ana; Danisor, Alin; Berescu, Serban

    2015-02-01

    In this paper we present a type of antipodal Vivaldi antenna design, which can be used for pulse radiation in UWB communication. The Vivaldi antenna is a special tapered slot antenna with planar structure which is easily to be integrated with transmitting elements and receiving elements to form a compact structure. When the permittivity is very large, the wavelength of slot mode is so short that the electromagnetic fields concentrate in the slot to form an effective and balanced transmission line. Due to its simple structure and small size the Vivaldi antennas are one of the most popular designs used in UWB applications. However, for a two-antenna radar system, there is a high mutual coupling between two such antennas due to open configuration. In this paper, we propose a new method for reducing this effect. The method was validated by simulating a system of two Vivaldi antennas in front of a standard target.

  9. Design and analysis of a lightweight prestressed antenna back-up structure

    Science.gov (United States)

    Ma, Zengxiang; Yang, Dehua; Cheng, Jingquan

    2010-07-01

    The planned Square Kilometer Array (SKA) includes three thousand 15m antennas. The radio flux density from the sun is stronger, so that a solar array, such as Frequency-Agile Solar Radiotelescope (FASR) with hundreds of dishes can have smaller dish size. Therefore, light weight, low cost dish design is of vital importance. The reflecting surface supported by an antenna back-up structure, generally, should have an RMS surface error less than λ/20 (λ. is the operating wavelength). For resisting gravitational, wind, and ice-snow loadings, an antenna dish also requires reasonable mode frequencies. In this paper, different low cost small or medium back-up structure designs are discussed, including double-layer truss design and prestressed dish design. Based on discussion, an innovative light weight, prestressed back-up structure is proposed for small or medium aperture antennas. Example of a small 4.5m aperture dish design working below 3GHz is presented. This design is a one-layer prestressed truss structure with low weight, ease installation, and low manufacture cost. Structural analysis and modal extraction results show the structure is much stiffer than the same structure without prestressed loading.

  10. New conceptual antenna with spiral structure and back Faraday shield for FWCD (fast wave current drive)

    International Nuclear Information System (INIS)

    Saigusa, M.; Moriyama, S.; Fujii, T.; Kimura, H.

    1994-01-01

    A new conceptual antenna, which we call as a spiral antenna, is proposed as a traveling wave antenna for fast wave current drive in tokamaks. The features of the spiral antenna are a sharp N z spectrum, easy impedance matching, N z controllable and good coupling. A back Faraday shield is proposed for improving the cooling design of Faraday shield and better antenna-plasma coupling. A helical support which is a compact and wide band support is proposed as a kind of quarter wave length stub supports. The RF properties of the spiral antenna and the back Faraday shield have been investigated by using mock-up antennas. The VSWR of spiral antenna is low at the wide frequency band from 15 MHz to 201 MHz. The back Faraday shield is effective for suppressing the RF toroidal electric field between adjacent currents straps. (author)

  11. Broadband Cylindrical Antenna and Method

    Science.gov (United States)

    2016-07-27

    May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is...Slotted cylinder antennas have been proposed in submarine applications before. For example, in U.S. Patent No. 6,127,983, Rivera and Josypenko disclose

  12. Compact circularly polarized truncated square ring slot antenna with suppressed higher resonances.

    Directory of Open Access Journals (Sweden)

    Mursyidul Idzam Sabran

    Full Text Available This paper presents a compact circularly polarized (CP antenna with an integrated higher order harmonic rejection filter. The proposed design operates within the ISM band of 2.32 GHz- 2.63 GHz and is suitable for example for wireless power transfer applications. Asymmetrical truncated edges on a square ring create a defected ground structure to excite the CP property, simultaneously realizing compactness. It offers a 50.5% reduced patch area compared to a conventional design. Novel stubs and slot shapes are integrated in the transmission line to reduce higher (up to the third order harmonics. The proposed prototype yields a -10 dB reflection coefficient (S11 impedance bandwidth of 12.53%, a 3 dB axial ratio bandwidth of 3.27%, and a gain of 5.64 dBi. Measurements also show good agreement with simulations.

  13. Placement insensitive antenna for RFID, sensing, and/or communication systems

    Science.gov (United States)

    Bernhard, Jennifer T.; Ruyle, Jessica E.

    2014-06-10

    An antenna includes a ground plane having a slot. The slot may be miniaturized using a meandered slot structure or other appropriate reactive loading method as an end load to one or both ends of the slot. An edge treatment may be included on one or more edges of the ground plane or a closely spaced reflecting plane. The antenna is structured to transmit or receive a signal independently or in response to electromagnetic radiation.

  14. A Near-Zero Refractive Index Meta-Surface Structure for Antenna Performance Improvement

    Directory of Open Access Journals (Sweden)

    Mohammad Habib Ullah

    2013-11-01

    Full Text Available A new meta-surface structure (MSS with a near-zero refractive index (NZRI is proposed to enhance the performance of a square loop antenna array. The main challenge to improve the antenna performance is increment of the overall antenna volume that is mitigated by assimilating the planar NZRI MSS at the back of the antenna structure. The proposed NZRI MSS-loaded CPW-fed (Co-Planar Waveguide four-element array antenna is designed on ceramic-bioplastic-ceramic sandwich substrate using high-frequency structure simulator (HFSS, a finite-element-method-based simulation tool. The gain and directivity of the antenna are significantly enhanced by incorporating the NZRI MSS with a 7 × 6 set of elements at the back of the antenna structure. Measurement results show that the maximum gains of the antenna increased from 6.21 dBi to 8.25 dBi, from 6.52 dBi to 9.05 dBi and from 10.54 dBi to 12.15 dBi in the first, second and third bands, respectively. The effect of the slot configuration in the ground plane on the reflection coefficient of the antenna was analyzed and optimized. The overall performance makes the proposed antenna appropriate for UHFFM (Ultra High Frequency Frequency Modulation telemetry-based space applications as well as mobile satellite, microwave radiometry and radio astronomy applications.

  15. U Patch Antenna for RFID and Wireless Applications

    International Nuclear Information System (INIS)

    Abi Saad, R.; Melhem, Z.; Nader, C.; Zaatar, Y.; Zaouk, D.

    2011-01-01

    in this paper, we propose a new multi-band patch antenna structure for embedded RFID (Radio Frequency Identification) readers and wireless communications. The proposed antenna is a dual band microstrip patch antenna using U-slot geometry. The operating frequencies of the proposed antenna are chosen as 2.4 and 0.9 (GHz), obtained by optimizing the physical dimensions of the U-slot. Several parameters have been investigated using Ansoft Designer software. The antenna is fed through a quarter wavelength transformer for impedance matching. An additional layer of alumina is added above the surface of the conductors to increase the performance of the antenna. (author)

  16. Development of a Compact Wide-Slot Antenna for Early Stage Breast Cancer Detection Featuring Circular Array Full-View Geometry

    Directory of Open Access Journals (Sweden)

    S. S. Tiang

    2014-01-01

    Full Text Available A novel planar type antenna printed on a high permittivity Rogers’ substrate is proposed for early stage microwave breast cancer detection. The design is based on a p-shaped wide-slot structure with 50 Ω microstrip feeding circuit to eliminate losses of transmission. The design parameters are optimized resulting in a good reflection coefficient at −10 dB from 4.5 to 10.9 GHz. Imaging result using inhomogeneous breast phantom indicates that the proposed antenna is capable of detecting a 5 mm size cancerous tumor embedded inside the fibroglandular region with dielectric contrast between the target and the surrounding materials ranging from 1.7 : 1 to 3.6 : 1.

  17. A Compact UWB Diversity Antenna

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available A compact printed ultrawideband (UWB diversity antenna with a size of 30 mm × 36 mm operating at a frequency range of 3.1–10.6 GHz is proposed. The antenna is composed of two semielliptical monopoles fed by two microstrip lines. Two semicircular slots, two rectangular slots, and one stub are introduced in the ground plane to adjust the impedance bandwidth of the antenna and improve the isolation between two feeding ports. The simulated and measured results show that impedance bandwidth of the proposed antenna can cover the whole UWB band with a good isolation of < −15 dB. The radiation patterns, peak antenna gain, and envelope correlation coefficient are also measured and discussed. The measured results show that the proposed antenna can be a good candidate for some portable MIMO/diversity UWB applications.

  18. Babinet-Inverted Optical Yagi-Uda Antenna for Unidirectional Radiation to Free Space

    Science.gov (United States)

    Kim, Jineun; Roh, Young-Geun; Cheon, Sangmo; Choe, Jong-Ho; Lee, Jongcheon; Lee, Jaesoong; Jeong, Heejeong; Kim, Un Jeong; Park, Yeonsang; Song, In Yong; Park, Q.-Han; Hwang, Sung Woo; Kim, Kinam; Lee, Chang-Won

    2014-06-01

    Plasmonic nanoantennas are key elements in nanophotonics capable of directing radiation or enhancing the transition rate of a quantum emitter. Slot-type magnetic-dipole nanoantennas, which are complementary structures of typical electric-dipole-type antennas, have received little attention, leaving their antenna properties largely unexplored. Here we present a novel magnetic-dipole-fed multi-slot optical Yagi-Uda antenna. By engineering the relative phase of the interacting surface plasmon polaritons between the slot elements, we demonstrate that the optical antenna exhibits highly unidirectional radiation to free space. The unique features of the slot-based magnetic nanoantenna provide a new possibility of achieving integrated features such as energy transfer from one waveguide to another by working as a future optical via.

  19. Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

    Science.gov (United States)

    Rengarajan, Sembiam

    2012-01-01

    Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an

  20. Slotted Waveguide and Antenna Study for HPM and RF Applications

    Science.gov (United States)

    2017-07-25

    conventional rectangular slot arrays. The proposed CSR-SW A provided higher peak gain than the conventional lambda /4 rectangu lar slot array and a...more compact s ize (55% size reductjon) compared to the lambda /2 rectangular slot array. Both the theoretic and measured results suggest a return loss...in terms of scattering matrix S is: (I-8) With the scattering matrix S, we can compute the scattering field at any position. The resonance of SCCR

  1. Compact Planar Ultrawideband Antennas with 3.5/5.2/5.8 GHz Triple Band-Notched Characteristics for Internet of Things Applications

    Directory of Open Access Journals (Sweden)

    Jian Dong

    2017-02-01

    Full Text Available Ultrawideband (UWB antennas, as core devices in high-speed wireless communication, are widely applied to mobile handsets, wireless sensor networks, and Internet of Things (IoT. A compact printed monopole antenna for UWB applications with triple band-notched characteristics is proposed in this paper. The antenna has a very compact size of 10 x 16 mm2 and is composed of a square slotted radiation patch and a narrow rectangular ground plane on the back of the substrate. First, by etching a pair of inverted T-shaped slots at the bottom of the radiation patch, one notched band at 5-6 GHz for rejecting the Wireless Local Area Network (WLAN is generated. Then, by cutting a comb-shaped slot on the top of the radiation patch, a second notched band for rejecting 3.5 GHz Worldwide Interoperability for Microwave Access (WiMAX is obtained. Further, by cutting a pair of rectangular slots and a C-shaped slot as well as adding a pair of small square parasitic patches at the center of the radiating patch, two separate notched bands for rejecting 5.2 GHz lower WLAN and 5.8 GHz upper WLAN are realized, respectively. Additionally, by integrating the slotted radiation patch with the narrow rectangular ground plane, an enhanced impedance bandwidth can be achieved, especially at the higher band. The antenna consists of linear symmetrical sections only and is easy for fabrication and fine-tuning. The measured results show that the designed antenna provides a wide impedance bandwidth of 150% from 2.12 to 14.80 GHz for VSWR < 2, except for three notched bands of 3.36–4.16, 4.92–5.36, and 5.68–6.0 GHz. Additionally, the antenna exhibits nearly omnidirectional radiation characteristics, low gain at the stopbands, and flat group delay over the whole UWB except at the stopbands. Simulated and experimental results show that the proposed antenna can provide good frequency-domain and time-domain performances at desired UWB frequencies and be an attractive candidate for

  2. A Comparison Between Jerusalem Cross and Square Patch Frequency Selective Surfaces for Low Profile Antenna Applications

    Science.gov (United States)

    Cure, David; Weller, Thomas; Miranda, Felix A.

    2011-01-01

    In this paper, a comparison between Jerusalem Cross (JC) and Square Patch (SP) based Frequency Selected Surfaces (FSS) for low profile antenna applications is presented. The comparison is aimed at understanding the performance of low profile antennas backed by high impedance surfaces. In particular, an end loaded planar open sleeve dipole (ELPOSD) antenna is examined due to the various parameters within its configuration, offering significant design flexibility and a wide operating bandwidth. Measured data of the antennas demonstrate that increasing the number of unit cells improves the fractional bandwidth. The antenna bandwidth increased from 0.8% to 1.8% and from 0.8% to 2.7% for the JC and SP structures, respectively. The number of unit cells was increased from 48 to 80 for the JC-FSS and from 24 to 48 for the SP-FSS.

  3. Dual-Resonant Implantable Circular Patch Antenna for Biotelemetry Communication

    Directory of Open Access Journals (Sweden)

    Rongqiang Li

    2016-01-01

    Full Text Available A compact broadband implantable circular patch antenna is designed and experimentally demonstrated for Medical Implant Communications Service (MICS band (402–405 MHz. Compared with other similar implantable antennas, the proposed antenna incorporates three advantages for biotelemetry communication. First, it can realize a broad impedance bandwidth by exhibiting dual resonances. Second, it can obtain a compact structure by introducing two arc-shaped slots, a rectangular slot and a circular slot on metal radiating patch. Finally, it can display a friendly shape by using a circular structure. The proposed antenna occupies a volume of about 431.5 mm3 (10.42 × 1.27π mm3, which is a compromise between miniaturization and bandwidth. The measured −10 dB impedance bandwidth is 55 MHz (385–440 MHz. Furthermore, the radiation performance and human body safety consideration of the antenna are examined and characterized.

  4. Metamaterial Embedded Wearable Rectangular Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    J. G. Joshi

    2012-01-01

    Full Text Available This paper presents an indigenous low-cost metamaterial embedded wearable rectangular microstrip patch antenna using polyester substrate for IEEE 802.11a WLAN applications. The proposed antenna resonates at 5.10 GHz with a bandwidth and gain of 97 MHz and 4.92 dBi, respectively. The electrical size of this antenna is 0.254λ×0.5λ. The slots are cut in rectangular patch to reduce the bending effect. This leads to mismatch the impedance at WLAN frequency band; hence, a metamaterial square SRR is embedded inside the slot. A prototype antenna has been fabricated and tested, and the measured results are presented in this paper. The simulated and measured results of the proposed antenna are found to be in good agreement. The bending effect on the performance of this antenna is experimentally verified.

  5. Implementation and Investigation of a Compact Circular Wide Slot UWB Antenna with Dual Notched Band Characteristics using Stepped Impedance Resonators

    Directory of Open Access Journals (Sweden)

    Yingsong Li

    2012-04-01

    Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with dual notched band characteristics is presented in this paper. The circular wide slot and circular radiation patch are utilized to broaden the impedance bandwidth of the UWB antenna. The dual notched band functions are achieved by employing two stepped impedance resonators (SIRs which etched on the circular radiation patch and CPW excitation line, respectively. The two notched bands can be controlled by adjusting the dimensions of the two stepped impedance resonators which give tunable notched band functions. The proposed dual notched band UWB antenna has been designed in details and optimized by means of HFSS. Experimental and numerical results show that the proposed antenna with compact size of 32 × 24 mm2, has an impedance bandwidth range from 2.8 GHz to 13.5 Hz for voltage standing-wave ratio (VSWR less than 2, except the notch bands 5.0 GHz - 6.2 GHz for HIPERLAN/2 and IEEE 802.11a (5.1 GHz - 5.9 GHz and 8.0 GHz - 9.3 GHz for satellite and military applications.

  6. An extraordinary transmission analogue for enhancing microwave antenna performance

    Directory of Open Access Journals (Sweden)

    Sarin V. Pushpakaran

    2015-10-01

    Full Text Available The theory of diffraction limit proposed by H.A Bethe limits the total power transfer through a subwavelength hole. Researchers all over the world have gone through different techniques for boosting the transmission through subwavelength holes resulting in the Extraordinary Transmission (EOT behavior. We examine computationally and experimentally the concept of EOT nature in the microwave range for enhancing radiation performance of a stacked dipole antenna working in the S band. It is shown that the front to back ratio of the antenna is considerably enhanced without affecting the impedance matching performance of the design. The computational analysis based on Finite Difference Time Domain (FDTD method reveals that the excitation of Fabry-Perot resonant modes on the slots is responsible for performance enhancement.

  7. CPW to CPS transition for feeding UWB antennas

    DEFF Research Database (Denmark)

    Butrym, Alexander; Pivnenko, Sergey

    2004-01-01

    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas in particular), bow-tie antennas, and other. Some numerical and experimental results...

  8. CPW to CPS transition for feeding UWB antennas

    DEFF Research Database (Denmark)

    Butrym, Alexander; Pivnenko, Sergey

    2006-01-01

    The paper considers a transition (balun) from Coplanar Waveguide (CPW) to Coplanar Stripline (CPS) which is non-resonant and suitable for feeding UWB antennas such as Tapered Slot Antennas (Vivaldi antennas, in particular), bow-tie antennas, and other. Some numerical and experimental results...

  9. Planar Ultrawideband Antenna with Photonically Controlled Notched Bands

    Directory of Open Access Journals (Sweden)

    Drasko Draskovic

    2013-01-01

    Full Text Available A design of a planar microstrip-fed ultrawideband (UWB printed circular monopole antenna with optically controlled notched bands is presented. The proposed antenna is composed of a circular ultrawideband patch, with an etched T-shaped slot controlled by an integrated silicon switch. The slot modifies the frequency response of the antenna suppressing 3.5–5 GHz band when the switch is in open state. The optical switch is controlled by a low-power near-infrared (808 nm laser diode, which causes the change in the frequency response of the antenna generating a frequency notch. This solution could be expanded to include several notches in the antenna frequency response achieving a fully reconfigurable UWB antenna. The antenna could be remotely controlled at large distances using optical fiber. The prototype antenna has been fully characterized to verify these design concepts.

  10. Log-periodic dipole antenna with low cross-polarization

    DEFF Research Database (Denmark)

    Pivnenko, Sergey

    2006-01-01

    In this work, log-periodic antennas with improved cross-polarization level were studied. It was found that some modifications of the traditional design lead to an essential improvement of the co-to-cross polarization ratio up to 40 dB. An improved design of a log-periodic dipole antenna with low...

  11. 60 GHz Milimeter-Wave Antennas for Point-to-Point 5G Communication System

    Directory of Open Access Journals (Sweden)

    Aishah A.S.

    2017-01-01

    Full Text Available In this paper microstrip patch antenna for millimeter-wave is proposed. Evolution of shape microstrip antenna are designed which is from rectangular antenna to triangle antenna and changed to triangle with slot. The proposed antenna configuration achieved for covering 5G wireless system. The lowest return loss of the antenna is -29.23dB which is triangle with slot and the maximum gain obtained is 8 db at the 61.93 GHz for the triangle antenna. This antenna are suitable for the 5G wireless application for short range and high rate communication system.

  12. Bridging the Gap between RF and Optical Patch Antenna Analysis via the Cavity Model.

    Science.gov (United States)

    Unal, G S; Aksun, M I

    2015-11-02

    Although optical antennas with a variety of shapes and for a variety of applications have been proposed and studied, they are still in their infancy compared to their radio frequency (rf) counterparts. Optical antennas have mainly utilized the geometrical attributes of rf antennas rather than the analysis tools that have been the source of intuition for antenna engineers in rf. This study intends to narrow the gap of experience and intuition in the design of optical patch antennas by introducing an easy-to-understand and easy-to-implement analysis tool in rf, namely, the cavity model, into the optical regime. The importance of this approach is not only its simplicity in understanding and implementation but also its applicability to a broad class of patch antennas and, more importantly, its ability to provide the intuition needed to predict the outcome without going through the trial-and-error simulations with no or little intuitive guidance by the user.

  13. High precision slotted cavity measurement of a novel ceramic state polymer electrolyte

    Science.gov (United States)

    Quan, Wei; NurulAfsar, Mohammed

    2018-01-01

    Thin film materials are already used in a variety of microwave and higher frequency applications such as electrically tunable microwave devices, integrated circuits like MMICs, radomes, and radar absorbing coating. The determination of the dielectric properties of these films is thus of significant importance. The measurement of complex dielectric permittivity of thin films is very difficult at microwave, millimeter, and THz frequencies because both the amplitude change and phase shift are not large enough to evaluate the real part of the dielectric permittivity. A specially designed transverse slotted cavity for X-band microwave measurement has been designed and constructed to employ with a vector network analyzer to evaluate the real part of dielectric permittivity of thin films accurately and conveniently. Commercially available polymer thin films are measured to validate the methods.

  14. Research on the Scattering Characteristics and the RCS Reduction of Circularly Polarized Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    W. Jiang

    2013-01-01

    Full Text Available Based on the study of the radiation and scattering of the circularly polarized (CP antenna, a novel radar cross-section (RCS reduction technique is proposed for CP antenna in this paper. Quasi-fractal slots are applied in the design of the antenna ground plane to reduce the RCS of the CP antenna. Both prototype antenna and array are designed, and their time-, frequency-, and space-domain characteristics are studied to authenticate the proposed technique. The simulated and measured results show that the RCS of the prototype antenna and array is reduced up to 7.85 dB and 6.95 dB in the band of 1 GHz–10 GHz. The proposed technique serves a candidate in the design of low RCS CP antennas and arrays.

  15. Performance of a Planar Leaky-Wave Slit Antenna for Different Values of Substrate Thickness

    Directory of Open Access Journals (Sweden)

    Niamat Hussain

    2017-10-01

    Full Text Available This paper presents the performance of a planar, low-profile, and wide-gain-bandwidth leaky-wave slit antenna in different thickness values of high-permittivity gallium arsenide substrates at terahertz frequencies. The proposed antenna designs consisted of a periodic array of 5 × 5 metallic square patches and a planar feeding structure. The patch array was printed on the top side of the substrate, and the feeding structure, which is an open-ended leaky-wave slot line, was etched on the bottom side of the substrate. The antenna performed as a Fabry-Perot cavity antenna at high thickness levels (H = 160 μm and H = 80 μm, thus exhibiting high gain but a narrow gain bandwidth. At low thickness levels (H = 40 μm and H = 20 μm, it performed as a metasurface antenna and showed wide-gain-bandwidth characteristics with a low gain value. Aside from the advantage of achieving useful characteristics for different antennas by just changing the substrate thickness, the proposed antenna design exhibited a low profile, easy integration into circuit boards, and excellent low-cost mass production suitability.

  16. DESIGN OF MULTILAYER APERTURE COUPLED STACKED MICROSTRIP PATCH ANTENNA FOR WLAN APPLICATIONS

    Directory of Open Access Journals (Sweden)

    P. Jothilakshmi

    2015-10-01

    Full Text Available One of the major drawbacks of microstrip patch antenna is its narrow bandwidth. The solution of this problem is to use aperture coupled stacked micro strip patch antenna. The antenna uses a combination of aperture coupled feeding technique and multi- layer radiating patch in order for the radiating elements are increase the gain bandwidth. The ‘I’ and ‘H’ shaped aperture slots are etched onto the ground plane. It is used to transfer the energy from feed line to stacked patch. A variation of the feed line length controls the selected aperture slots to be active. The waves from the selected activated aperture slots will radiate to particular radiating patch and achieve the desired resonant frequency. The air gap is used to avoid coupling loss between the aperture slots and stacked patches. The observed simulated and measured results show that the proposed antenna structure resonated at 2.51 GHz frequency with reduced return loss and optimum voltage standing wave ratio.

  17. The Ultrawideband Leaky Lens Antenna

    NARCIS (Netherlands)

    Bruni, S.; Neto, A.; Marliani, F.

    2007-01-01

    A novel directive and nondispersive antenna is presented: the ultrawideband (UWB) leaky lens. It is based on the broad band Cherenkov radiation occurring at a slot printed between different infinite homogeneous dielectrics. The first part of the paper presents the antenna concept and the UWB design.

  18. Small Square Reconfigurable Antenna with Switchable Single/Tri-Band Functions

    Directory of Open Access Journals (Sweden)

    M. Borhani Kakhki

    2016-04-01

    Full Text Available A novel frequency reconfigurable slot antenna for suitable switchable radiations at WLAN and a tri-band at Bluetooth, WiMAX and upper WLAN applications is designed and fabricated. Switchable frequency responses are achieved by implementation of a PIN diode within the antenna ground plane. The antenna structure is consist of a square radiation patch with an E-shaped slot, a modified ground plane with an inverted T-shaped strip that act as a parasitic stub and two parallel slots and a protruded strip which is connected to the parasitic stub with a PIN diode. The presented antenna has a compact size of 20×20 mm2 while providing switchable radiations at 2.36-2.5 GHz Bluetooth, 3.51-3.79 GHz WiMAX, and 5.47-5.98 GHz WLAN when diode is ON and 5.04-6.13 GHz WLAN when diode is OFF.

  19. The Gain Estimation of a Fabry-Perot Cavity (FPC Antenna with a Finite Dimension

    Directory of Open Access Journals (Sweden)

    Taek-Sun Kwon

    2017-10-01

    Full Text Available In this paper, we have presented an equation for estimating the gain of a Fabry-Perot cavity (FPC antenna with a finite dimension. When an FPC antenna has an infinite dimension and its height is half of a wavelength, the maximum gain of that FPC antenna can be obtained theoretically. If the FPC antenna does not have a dimension sufficient for multiple reflections between a partially reflective surface (PRS and the ground, its gain must be less than that of an FPC antenna that has an infinite dimension. In addition, the gain of an FPC antenna increases as the dimension of a PRS increases and becomes saturated from a specific dimension. The specific dimension where the gain starts to saturate also gets larger as the reflection magnitude of the PRS becomes closer to one. Thus, it would be convenient to have a gain equation when considering the dimension of an FPC antenna in order to estimate the exact gain of the FPC antenna with a specific dimension. A gain versus the dimension of the FPC antenna for various reflection magnitudes of PRS has been simulated, and the modified gain equation is produced through the curve fitting of the full-wave simulation results. The resulting empirical gain equation of an FPC antenna whose PRS dimension is larger than 1.5λ0 has been obtained.

  20. Quad Band Handset Antenna for LTE MIMO and WLAN Application

    Directory of Open Access Journals (Sweden)

    H. S. Wong

    2014-01-01

    Full Text Available A compact quad band antenna for long-term evolution (LTE MIMO and WLAN application in the handset is presented in this paper. The proposed antenna comprises two symmetrical quarter wavelength radiating strips and a slotted ground plane. On the ground plane, a T-shaped slot is cut from the bottom. Two symmetrical P-shaped slots are etched at both sides of the ground plane. The radiating strips and slots generate a lower resonant at 780 MHz and an upper resonant at 2.350 GHz to cover LTE 700 Band 14, LTE 2300, 2.4 GHz WLAN, and LTE 2500. A novel isolation technique by placing a rectangular patch between the radiating strips is presented. The rectangular patch creates a dedicated current path for each radiating strip. The proposed antenna has high isolation of less than −18 dBi at LTE 2300, 2.4 GHz WLAN, and LTE 2500 band.

  1. Slotted cage resonator for high-field magnetic resonance imaging of rodents

    Energy Technology Data Exchange (ETDEWEB)

    Marrufo, O; Vasquez, F; Solis, S E; Rodriguez, A O, E-mail: arog@xanum.uam.mx [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico)

    2011-04-20

    A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

  2. Radiation and scattering from cylindrically conformal printed antennas. Ph.D. Thesis Final Report

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.

    1994-01-01

    Microstrip patch antennas offer considerable advantages in terms of weight, aerodynamic drag, cost, flexibility, and observables over more conventional protruding antennas. These flat patch antennas were first proposed over thirty years ago by Deschamps in the United States and Gutton and Baisinot in France. Such antennas have been analyzed and developed for planar as well as curved platforms. However, the methods used in these designs employ gross approximations, suffer from extreme computational burden, or require expensive physical experiments. The goal of this thesis is to develop accurate and efficient numerical modeling techniques which represent actual antenna structures mounted on curved surfaces with a high degree of fidelity. In this thesis, the finite element method is extended to cavity-backed conformal antenna arrays embedded in a circular, metallic, infinite cylinder. Both the boundary integral and absorbing boundary mesh closure conditions will be used for terminating the mesh. These two approaches will be contrasted and used to study the scattering and radiation behavior of several useful antenna configurations. An important feature of this study will be to examine the effect of curvature and cavity size on the scattering and radiation properties of wraparound conformal antenna arrays.

  3. An efficient hexagonal switched beam antenna structure based on Fabry-Perot cavity leaky-wave antenna

    Science.gov (United States)

    Aymen El Cafsi, Mohamed; Nedil, Mourad; Osman, Lotfi; Gharsallah, Ali

    2015-11-01

    A novel design of switched beam antenna (SBA) system based on Fabry-Perot cavity leaky-wave antenna (FPC LWA) is designed and fabricated for base station operating in the unlicensed ISM central frequency band at 5.8 GHz of the wireless local area network (WLAN) standard. The proposed SBA is designed with hexagonal shape of FPC LWA Arrays in order to get 360° of coverage. The single element of FPC LWA array is composed of a patch antenna and covered by a Partially Reflective Surface (PRS), which is composed of a Metal Strip Grating and printed on a high permittivity Superstrate. First, the Transmission Line Model of FPC LWA is introduced to analyse and calculate the far-field components in E- and H planes by using the Transverse Equivalent Network. This approach is then compared with other full wave's commercial software such as Ansoft HFSS and CST Microwave Studio. Second, a parametric study is performed to evaluate the effect of the angle formed by the two successive FPC LWA on the radiation efficiency of the activate sector. To examine the performance of the proposed SBA, experimental prototype was fabricated and measured. As a result, multiple orthogonal beams (six beams) of 10 dBi of gain with low Side Lobes Level and 360° of coverage are produced. This SBA structure is suitable for WLAN communication systems.

  4. A Rectangular Planar Spiral Antenna for GIS Partial Discharge Detection

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2014-01-01

    Full Text Available A rectangular planar spiral antenna sensor was designed for detecting the partial discharge in gas insulation substations (GIS. It can expediently receive electromagnetic waves leaked from basin-type insulators and can effectively suppress low frequency electromagnetic interference from the surrounding environment. Certain effective techniques such as rectangular spiral structure, bow-tie loading, and back cavity structure optimization during the antenna design process can miniaturize antenna size and optimize voltage standing wave ratio (VSWR characteristics. Model calculation and experimental data measured in the laboratory show that the antenna possesses a good radiating performance and a multiband property when working in the ultrahigh frequency (UHF band. A comparative study between characteristics of the designed antenna and the existing quasi-TEM horn antenna was made. Based on the GIS defect simulation equipment in the laboratory, partial discharge signals were detected by the designed antenna, the available quasi-TEM horn antenna, and the microstrip patch antenna, and the measurement results were compared.

  5. Bandwidth enhancement of a microstrip patch antenna for ultra-wideband applications

    Science.gov (United States)

    Anum, Khanda; Singh, Milind Saurabh; Mishra, Rajan; Tripathi, G. S.

    2018-04-01

    The microstrip antennas are used where size, weight, cost, and performance are constraints. Microstrip antennas (MSA) are being used in many government and commercial applications among which it is mostly used in wireless communication. The proposed antenna is designed for Ultra-wideband (UWB), it is designed on FR4 substrate material with ɛr = 4.3 and 0.0025 loss tangent. The shape and size of patch in microstrip patch antenna plays an important role in its performance. In the proposed antenna design the respective changes have been introduced which includes slotting the feedline,adding a curved slot in patch and change in patch shape itself to improve the bandwidth of the conventional antenna. The simulated results of proposed antenna shows impedance bandwidth (defined by 10 dB return loss) of 2-11.1GHz, VSWRcommunication at 7.25-8.395 GHz.

  6. A Hybrid Optimization Algorithm for Low RCS Antenna Design

    Directory of Open Access Journals (Sweden)

    W. Shao

    2012-12-01

    Full Text Available In this article, a simple and efficient method is presented to design low radar cross section (RCS patch antennas. This method consists of a hybrid optimization algorithm, which combines a genetic algorithm (GA with tabu search algorithm (TSA, and electromagnetic field solver. The TSA, embedded into the GA frame, defines the acceptable neighborhood region of parameters and screens out the poor-scoring individuals. Thus, the repeats of search are avoided and the amount of time-consuming electromagnetic simulations is largely reduced. Moreover, the whole design procedure is auto-controlled by programming the VBScript language. A slot patch antenna example is provided to verify the accuracy and efficiency of the proposed method.

  7. Flexible Aperture Tuning Solution for Cellular Main Antenna in Metallic Back Cover Mobile Phone

    Directory of Open Access Journals (Sweden)

    Yew Choon Mark Tan

    2017-10-01

    Full Text Available Metal housing has been used extensively on portable communication devices such as on mobile phones and tablets. The choice of metal housing ranges from metallic rim to metallic back cover. This metal housing tends to improve the outlook appearance of the mobile devices, and add mechanical strength towards the mobile devices. However, from the aspect of the communication antenna, the metal housing often posts great challenges towards the flexibility in antenna design and reduction in antenna performance. This paper presents an approach to overcome the challenges by integrating the metal housing of the mobile phone as part of the antenna, along with the introduction of tunable antenna concept to provide different forms of Aperture Tuning to the Cellular Main Antenna, to satisfy its wide frequency band coverages for the 2nd, 3rd and 4th Generation (2G, 3G and 4G mobile network.

  8. Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform.

    Science.gov (United States)

    Barrios, C A; Sánchez, B; Gylfason, K B; Griol, A; Sohlström, H; Holgado, M; Casquel, R

    2007-05-28

    We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of <20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

  9. A New Kind of Circular Polarization Leaky-Wave Antenna Based on Substrate Integrated Waveguide

    Directory of Open Access Journals (Sweden)

    Chong Zhang

    2015-01-01

    Full Text Available A new kind of circular polarization leaky-wave antenna with N-shaped slots cut in the upper side of substrate integrated waveguide (SIW is investigated and presented. The radiation pattern and polarization axial ratio of the leaky-wave antenna are studied. The results show that the width of N-shaped slots has significant effect on the circular polarization property of the antenna. By properly choosing structural parameters, the SIW based leaky-wave antenna can realize circular polarization with excellent axial ratio in 8 GHz satellite band.

  10. Multislot microstrip antenna for ultra-wide band applications

    Directory of Open Access Journals (Sweden)

    Noor M. Awad

    2018-01-01

    Full Text Available In this paper designs of both planar ultra-wide band (UWB antenna and UWB antenna with two rejected bands are given. The antenna consists of a rectangular patch etched on FR4-substrate with 50 Ω feed line. The rectangular patch has one round cut at each corner with one slot in the ground plane. The simulated bandwidth with return loss (RL ⩾ 10 dB is 3.42–11.7 GHz. The rejected bands are the WLAN and X-bands, achieved by inserting slots in the patch and the feed. The simulated results of the proposed antenna indicate higher gain at the passbands while a sharp drop at the rejected bands is seen. The radiation pattern is of dipole shape in the E-plane and almost omnidirectional in the H-plane. The high frequency structure simulator (HFSS is used to design and simulate the antennas behavior over the different frequency ranges. Measurements confirm the antenna characteristic as predicted in the simulation with a slight shift in frequencies.

  11. Slots in dielectric image line as mode launchers and circuit elements

    Science.gov (United States)

    Solbach, K.

    1981-01-01

    A planar resonator model is used to investigate slots in the ground plane of dielectric image lines. An equivalent circuit representation of the slot discontinuity is obtained, and the launching efficiency of the slot as a mode launcher is analyzed. Slots are also shown to be useful in the realization of dielectric image line array antennas. It is found that the slot discontinuity can be shown as a T-junction of the dielectric image line and a metal waveguide. The launching efficiency is found to increase with the dielectric constant of the dielectric image line, exhibiting a maximum value for guides whose height is slightly less than half a wavelength in the dielectric medium. The measured launching efficiencies of low permittivity dielectric image lines are found to be in good agreement with calculated values

  12. Design and test of SX-FEL cavity BPM

    International Nuclear Information System (INIS)

    Yuan Renxian; Zhou Weimin; Chen Zhichu; Yu Luyang; Wang Baopen; Leng Yongbin

    2013-01-01

    This paper reports the design and cold test of the cavity beam position monitor (CBPM) for SX-FEL to fulfill the requirement of beam position measurement resolution of less than 1 μm, even 0.1 μm. The CBPM was optimized by using a coupling slot to damp the TM 010 mode in the output signal. The isolation of TM 010 mode is about 117 dB, and the shunt impedance is about 200 Ω@4.65 GHz with the quality factor 80 from MAFIA simulation and test result. A special antenna was designed to load power for reducing excitation of other modes in the cavity. The resulting output power of TM 110 mode was about 90 mV/mm when the source was 6 dBm, and the accomplishable minimum voltage was about 200 μV. The resolution of the CBPM was about 0.1 μm from the linear fitting result based on the cold test. (authors)

  13. Numerical study on non-locally reacting behavior of nacelle liners incorporating drainage slots

    Science.gov (United States)

    Chen, Chao; Li, Xiaodong; Thiele, Frank

    2018-06-01

    For acoustic liners used in current commercial nacelles, in order to prevent any liquid accumulating in the resonators, drainage slots are incorporated on the partition walls between closely packed cavities. Recently, an experimental study conducted by Busse-Gerstengarbe et al. shown that the cell interaction introduced by drainage slots causes an additional dissipation peak which increases with the size of the slot. However, the variation of damping process due to drainage slots is still not fully understood. Therefore, a numerical study based on computational aeroacoustic methods is carried out to investigate the mechanism of the changed attenuation characteristics due to drainage slots in presence of grazing incident sound waves with low or high intensities. Different slot configurations are designed based on the generic non-locally reacting liner model adopted in the experimental investigation. Both 2-D and 3-D numerical simulations of only slit resonators are carried out. Numerical results indicate that the extra peak is a result of a resonance excited in the second cavity at specific frequency. Under high sound pressure level incoming waves, the basic characteristics of the acoustic performance remain. However, vortex shedding transpires at the resonances around both the slits and the drainage slot. Vorticity contours show that the connection of two coupled cavities decreases the strength of vortex shedding around the basic Helmholtz resonance due to a higher energy reflection. Meanwhile, the cell interaction significantly increases the vorticity magnitude near the extra resonant frequency. Finally, a semi-empirical model is derived to predict the extra attenuation peak frequency.

  14. Feasibility of Using a Novel 2.45 GHz Double Short Distance Slot Coaxial Antenna for Minimally Invasive Cancer Breast Microwave Ablation Therapy: Computational Model, Phantom, and In Vivo Swine Experimentation

    Science.gov (United States)

    Cepeda Rubio, M. F. J.; Leija, L.

    2018-01-01

    Microwave ablation (MWA) by using coaxial antennas is a promising alternative for breast cancer treatment. A double short distance slot coaxial antenna as a newly optimized applicator for minimally invasive treatment of breast cancer is proposed. To validate and to analyze the feasibility of using this method in clinical treatment, a computational model, phantom, and breast swine in vivo experimentation were carried out, by using four microwave powers (50 W, 30 W, 20 W, and 10 W). The finite element method (FEM) was used to develop the computational model. Phantom experimentation was carried out in breast phantom. The in vivo experimentation was carried out in a 90 kg swine sow. Tissue damage was estimated by comparing control and treated micrographs of the porcine mammary gland samples. The coaxial slot antenna was inserted in swine breast glands by using image-guided ultrasound. In all cases, modeling, in vivo and phantom experimentation, and ablation temperatures (above 60°C) were reached. The in vivo experiments suggest that this new MWA applicator could be successfully used to eliminate precise and small areas of tissue (around 20–30 mm2). By modulating the power and time applied, it may be possible to increase/decrease the ablation area. PMID:29854360

  15. The Simulation and Experiment of a Non-Cross-Feeding Printed Log-Periodic Antenna

    Directory of Open Access Journals (Sweden)

    Chun-Ying Kang

    2015-01-01

    Full Text Available A non-cross-fed printed log-periodic antenna is simulated and studied experimentally. To avoid complex feeding with long coaxial line, the non-cross-feeding structure is applied in this antenna. The software CST Microwave Studio is employed to simulate the proposed antenna, and the optimized antenna model is obtained. According to the simulation results, the antenna prototype is produced and measured. Simulation and measured results show that the antenna is with S11<-10 dB in band of 4.2–9.2 GHz. And the radiation pattern and gain vary steadily in this band, which achieves requirements for wideband antenna. This antenna design can be extended to the design of the antenna integrated in communication circuit.

  16. Multiband and wideband monopole antenna for GSM900 and other wireless applications

    KAUST Repository

    Abutarboush, Hattan; Nasif, H.; Nilavalan, Rajagopal; Cheung, Sing Wai

    2012-01-01

    In this letter, the design of a compact monopole antenna for multiband and wideband operations is proposed. The antenna has three distinct frequency bands, centered at 0.94, 2.7, and 4.75 GHz. The antenna has a compact size of only 30×40×1.57 mm$ 3 including the ground plane. The multiband and wideband operations are achieved by using an E-shaped slot on the ground plane. The design procedure is also discussed. The frequency bands can be independently controlled by using the parameters of the E-slot. The impedance bandwidth, current distributions, radiation patterns, gain, and efficiency of the antenna are studied by computer simulation and measurements. © 2011 IEEE.

  17. Active control of turbulent boundary layer-induced sound transmission through the cavity-backed double panels

    Science.gov (United States)

    Caiazzo, A.; Alujević, N.; Pluymers, B.; Desmet, W.

    2018-05-01

    This paper presents a theoretical study of active control of turbulent boundary layer (TBL) induced sound transmission through the cavity-backed double panels. The aerodynamic model used is based on the Corcos wall pressure distribution. The structural-acoustic model encompasses a source panel (skin panel), coupled through an acoustic cavity to the radiating panel (trim panel). The radiating panel is backed by a larger acoustic enclosure (the back cavity). A feedback control unit is located inside the acoustic cavity between the two panels. It consists of a control force actuator and a sensor mounted at the actuator footprint on the radiating panel. The control actuator can react off the source panel. It is driven by an amplified velocity signal measured by the sensor. A fully coupled analytical structural-acoustic model is developed to study the effects of the active control on the sound transmission into the back cavity. The stability and performance of the active control system are firstly studied on a reduced order model. In the reduced order model only two fundamental modes of the fully coupled system are assumed. Secondly, a full order model is considered with a number of modes large enough to yield accurate simulation results up to 1000 Hz. It is shown that convincing reductions of the TBL-induced vibrations of the radiating panel and the sound pressure inside the back cavity can be expected. The reductions are more pronounced for a certain class of systems, which is characterised by the fundamental natural frequency of the skin panel larger than the fundamental natural frequency of the trim panel.

  18. Multifunctional Antenna with Reconfigurable Ultra-Wide Band Characteristics

    Directory of Open Access Journals (Sweden)

    A. Verma

    2017-09-01

    Full Text Available In this paper a multifunctional antenna is presented which offers an ultra-wideband (UWB operation, an UWB operation with two switchable notches and reconfigurable dual-band operation for WiMAX and WLAN applications, respectively. Total seven functions/states could be achieved from a single antenna using an electronic switching. The antenna uses dual slots on the ground plane to provide a wide bandwidth, ranging from 3.1 GHz to 10.6 GHz. U-Shaped slot and C-Shaped printed strip in the ground are used to generate two notches at 3.6 GHz(WiMAX and 5.2 GHz (WLAN/ WiFi bands, respectively. Moreover, four parasitic strips are added in the feed side to make antenna functional at either3.6 GHz or 5.2 GHz or both. Total Five PIN diodes are required to obtain seven operations from the proposed antenna. Seven structures are fabricated and measured to verify the seven states and results are found in good agreement with estimated results obtained from the simulation.

  19. Electromagnetic interference reduction using electromagnetic bandgap structures in packages, enclosures, cavities, and antennas

    Science.gov (United States)

    Mohajer Iravani, Baharak

    Electromagnetic interference (EMI) is a source of noise problems in electronic devices. The EMI is attributed to coupling between sources of radiation and components placed in the same media such as package or chassis. This coupling can be either through conducting currents or through radiation. The radiation of electromagnetic (EM) fields is supported by surface currents. Thus, minimizing these surface currents is considered a major and critical step to suppress EMI. In this work, we present novel strategies to confine surface currents in different applications including packages, enclosures, cavities, and antennas. The efficiency of present methods of EM noise suppression is limited due to different drawbacks. For example, the traditional use of lossy materials and absorbers suffers from considerable disadvantages including mechanical and thermal reliability leading to limited life time, cost, volume, and weight. In this work, we consider the use of Electromagnetic Band Gap (EBG) structures. These structures are suitable for suppressing surface currents within a frequency band denoted as the bandgap. Their design is straight forward, they are inexpensive to implement, and they do not suffer from the limitations of the previous methods. A new method of EM noise suppression in enclosures and cavity-backed antennas using mushroom-type EBG structures is introduced. The effectiveness of the EBG as an EMI suppresser is demonstrated using numerical simulations and experimental measurements. To allow integration of EBGs in printed circuit boards and packages, novel miniaturized simple planar EBG structures based on use of high-k dielectric material (epsilonr > 100) are proposed. The design consists of meander lines and patches. The inductive meander lines serve to provide current continuity bridges between the capacitive patches. The high-k dielectric material increases the effective capacitive load substantially in comparison to commonly used material with much lower

  20. DUAL POLARIZATION ANTENNA ARRAY WITH VERY LOW CROSS POLARIZATION AND LOW SIDE LOBES

    DEFF Research Database (Denmark)

    1997-01-01

    The present invention relates to an antenna array adapted to radiate or receive electromagnetic waves of one or two polarizations with very low cross polarization and low side lobes. An antenna array comprising many antenna elements, e.g. more than ten antenna elements, is provided in which...... formation of grating lobes are inhibited in selected directions of the radiation and cross polarization within the main lobe is suppressed at least 30 dB below the main lobe peak value. According to a preferred embodiment of the invention, the antenna elements of the antenna array comprise probe-fed patches...

  1. Unidirectional Magneto-Electric Dipole Antenna for Base Station: A Review

    Science.gov (United States)

    Idayachandran, Govindanarayanan; Nakkeeran, Rangaswamy

    2018-04-01

    Unidirectional base station antenna design using Magneto-Electric Dipole (MED) has created enormous interest among the researchers due to its excellent radiation characteristics like low back radiation, symmetrical radiation at E-plane and H-plane compared to conventional patch antenna. Generally, dual polarized antennas are used to increase channel capacity and reliability of the communication systems. In order to serve the evolving mobile communication standards like long term evolution LTE and beyond, unidirectional dual polarized MED antenna are required to have broad impedance bandwidth, broad half power beamwidth, high port isolation, low cross polarization level, high front to back ratio and high gain. In this paper, the critical electrical requirements of the base station antenna and frequently used frequency bands for modern mobile communication have been presented. It is followed by brief review on broadband patch antenna and discussion on complementary antenna concepts. Finally, the performance of linearly polarized and dual polarized magneto-electric dipole antennas along with their feeding techniques are discussed and summarized. Also, design and modeling of developed MED antenna is presented.

  2. Balancing Uplink and Downlink under Asymmetric Traffic Environments Using Distributed Receive Antennas

    Science.gov (United States)

    Sohn, Illsoo; Lee, Byong Ok; Lee, Kwang Bok

    Recently, multimedia services are increasing with the widespread use of various wireless applications such as web browsers, real-time video, and interactive games, which results in traffic asymmetry between the uplink and downlink. Hence, time division duplex (TDD) systems which provide advantages in efficient bandwidth utilization under asymmetric traffic environments have become one of the most important issues in future mobile cellular systems. It is known that two types of intercell interference, referred to as crossed-slot interference, additionally arise in TDD systems; the performances of the uplink and downlink transmissions are degraded by BS-to-BS crossed-slot interference and MS-to-MS crossed-slot interference, respectively. The resulting performance unbalance between the uplink and downlink makes network deployment severely inefficient. Previous works have proposed intelligent time slot allocation algorithms to mitigate the crossed-slot interference problem. However, they require centralized control, which causes large signaling overhead in the network. In this paper, we propose to change the shape of the cellular structure itself. The conventional cellular structure is easily transformed into the proposed cellular structure with distributed receive antennas (DRAs). We set up statistical Markov chain traffic model and analyze the bit error performances of the conventional cellular structure and proposed cellular structure under asymmetric traffic environments. Numerical results show that the uplink and downlink performances of the proposed cellular structure become balanced with the proper number of DRAs and thus the proposed cellular structure is notably cost-effective in network deployment compared to the conventional cellular structure. As a result, extending the conventional cellular structure into the proposed cellular structure with DRAs is a remarkably cost-effective solution to support asymmetric traffic environments in future mobile cellular

  3. Compact printed two dipole array antenna with a high front-back ratio for ultra-high-frequency radio-frequency identification handheld reader applications

    DEFF Research Database (Denmark)

    Liu, Qi; Zhang, Shuai; He, Sailing

    2015-01-01

    A printed two-dipole array antenna with a high front-back ratio is proposed for ultra-high-frequency (UHF) radio-frequency identification handheld readers. The proposed antenna is a parasitic dual-element array with the ends of both elements folded back towards each other for additional coupling....

  4. RFID antenna design for circular polarization in UHF band

    Science.gov (United States)

    Shahid, Hamza; Khan, Muhammad Talal Ali; Tayyab, Umais; Irshad, Usama Bin; Alkhazraji, Emad; Javaid, Muhammad Sharjeel

    2017-05-01

    A miniature half cross dipole antenna for defense and aerospace RFID applications in UHF band is presented. The dipole printed line arms are half crossed shape on top of dielectric substrate backed by reactive impedance surface. The antenna fed by a coaxial cable at the gap separating the dipole arms. Our design is intended to work at 2.42 GHz for RFID readers. The radiation pattern obtained has HPBW of 112, return loss of 22.24 dB and 90 MHz bandwidth.

  5. A Compact Printed Quadruple Band-Notched UWB Antenna

    Directory of Open Access Journals (Sweden)

    Xiaoyin Li

    2013-01-01

    Full Text Available A novel compact coplanar waveguide- (CPW- fed ultrawideband (UWB printed planar volcano-smoke antenna (PVSA with four band-notches for various wireless applications is proposed and demonstrated. The low-profile antenna consists of a C-shaped parasitic strip to generate a notched band at 8.01~8.55 GHz for the ITU band, two C-shaped slots, and an inverted U-shaped slot etched in the radiator patch to create three notched bands at 5.15~5.35 GHz, 5.75~5.85 GHz, and 7.25~7.75 GHz for filtering the WLAN and X-band satellite signals. Simulated and measured results both confirm that the proposed antenna has a broad bandwidth of 3.1~12 GHz with VSWR < 2 and good omnidirectional radiation patterns with four notched-bands.

  6. A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection.

    Science.gov (United States)

    Syed, Avez; Aldhaheri, Rabah W

    2016-01-01

    A low-cost coplanar waveguide fed compact ultrawideband (UWB) antenna with band rejection characteristics for wireless local area network (WLAN) is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9-13.7 GHz) with VSWR applications.

  7. Dual Band Parasitic Element Patch Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    BAG Biplab

    2017-05-01

    Full Text Available In this paper, a single layer coaxial fed dual band slotted microstrip antenna is proposed. The proposed antenna consists of two direct couple parasitic elements and L-shape slots on the main resonating element. Two resonant modes are excited and it covers 4G LTE and WLAN middle band. The -10dB impedance bandwidth for resonant frequency of 2.35GHz and 5.28GHz are 140MHz (2.25-2.39GHz and 570MHz (5.18-5.75GHz, respectively. The measured VSWR at 2.35GHz is 1.27 and at 5.28GHz is 1.41. The proposed antenna is simple in design and compact in size. The simulated and measured results are in good agreement.

  8. ICRF antenna modifications and additions for TFTR: Relevance to BPX/ITER projections

    International Nuclear Information System (INIS)

    Hosea, J.; Phillips, C.K.; Raftopoulos, S.; Stevens, J.; Wilson, J.R.

    1991-01-01

    The TFTR Bay L and M antennas have been modified to improve their power handling capability. In particular, the Bay L antenna, which exhibited a lower than expected loading resistance, now has a configuration similar to that of Bay M -- slotted walls and septum -- and together with Bay M is expected to support 7 MW operations. The in situ loading enhancement achieved for the Modified Bay L design will serve to quantify models for the coupling effects of slots. Also, comparisons with Bay M loading performance will elucidate wave spectrum and antenna location (relative to in-vessel structures) effects. Two new antennas, with single/double row shields slanted at 6 degree (along B) are to be added in the near future to augment the power capability to ∼12.5 MW. The relevance of the four antenna array features to quantifying BPX/ITER antenna characteristic projections for heating and current drive is discussed. 8 refs., 5 figs

  9. Switchable Phased Antenna Array with Passive Elements for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Syrytsin, Igor A.; Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    In this paper, a reconfigurable phased antenna array system is constructed for the mobile terminals in the context of 5G communication system. The proposed antenna system operates at the resonance frequency of 28 GHz. The reconfigurability of the antenna element is achieved by using a passive slot...

  10. Analysis of a Compact Wideband Slotted Antenna for Ku Band Applications

    Directory of Open Access Journals (Sweden)

    M. R. Ahsan

    2014-01-01

    Full Text Available The design procedure and physical module of a compact wideband patch antenna for Ku band application are presented in this paper. Finite element method based on 3D electromagnetic field solver has been utilized for the designing and analyzing process of proposed microstrip line fed modified E-H shaped electrically small patch antenna. After successful completion of the design process through various simulations, the proposed antenna has been fabricated on printed circuit board (PCB and its characteristics have been studied. The parameters of the proposed antenna prototype have been measured in standard far-field rectangular shape anechoic measurement compartment. It is apparent from the measured antenna parameters that the proposed antenna achieved almost stable variation of radiation pattern over the entire operational band with 1380 MHz of -10 dB return loss bandwidth. The maximum gain of 7.8 dBi and 89.97% average efficiency within the operating band from 17.15 GHz to 18.53 GHz ensure the suitability of the proposed antenna for Ku band applications.

  11. An FSS-Backed 20/30 GHz Circularly Polarized Reflectarray for a Shared Aperture L- and Ka-Band Satellite Communication Antenna

    DEFF Research Database (Denmark)

    Smith, Thomas Gunst; Gothelf, Ulrich; Kim, Oleksiy S.

    2014-01-01

    antenna. The reflectarray is based on the concentric dual split-loop element backed by a concentric dual-loop FSS element. The reflectarray comprises 80 × 80 elements and it is printed on a 40 ×40 cm2 Rogers 5880 substrate, while the L-band antenna is a 2 × 2 patch array. The reflectarray antenna has been...

  12. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    On the basis of the results obtained by Silver and Saunders [4] for the field radiated from an arbitrary slot in a perfectly conducting circular cylinder, expressions have been derived for the field radiated by a narrow helical slot, with an arbitrary aperture field distribution, in a circular...... antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...

  13. Performance Comparison Of Triangle Antenna of 60 GHz for 5G Wireless Communication Network

    Directory of Open Access Journals (Sweden)

    Aishah A.S.

    2017-01-01

    Full Text Available In this paper microstrip triangle with slot antenna for 5G wireless communication network are proposed. The microstip triangle antenna is design and operating 60 GHz milimeter-wave frequency band and it's suitable for 5G wireless communication. The substrates are chosen in the design, which are RogerRT5880 with copper thickness 0.035 mm to analyze their effect toward milimeter-wave performance on the designed. The designed and analysis is performed by using CST Microwave Studio. The lowest return loss of the antenna is -24.75dB which is triangle with slot and the maximum gain obtained is 6.82 db at the 59.68GHz for this antenna. The antenna is considering the gain, return loss and size, the microstrip antenna can be a suitable candidate for the 5G wireless application for short range high speed communication.

  14. Theoretical and experimental study of microstrip-to-slot line uniplanar transition

    Science.gov (United States)

    Yook, Jong-Gwan; Dib, Nihad I.; Katehi, Linda P. B.; Simons, Rainee N.; Taub, Susan R.

    1994-05-01

    Recent advances in MMCI technology make it possible to construct transitions from CPW-to-microstrip with via hole, microstrip-to-slot line and microshield line-to-CPW all of which have potential applications in the feed network of antennas. In this study we investigate the characteristics of the microstrip-to-slot line uniplanar transition using the finite element methods (FEM) and finite difference time domain (FDTD) techniques, and compared the theoretical results with the measurements. In both cases, the results agree with the measurements within a few percent.

  15. Large-Aperture Membrane Active Phased-Array Antennas

    Science.gov (United States)

    Karasik, Boris; McGrath, William; Leduc, Henry

    2009-01-01

    Large-aperture phased-array microwave antennas supported by membranes are being developed for use in spaceborne interferometric synthetic aperture radar systems. There may also be terrestrial uses for such antennas supported on stationary membranes, large balloons, and blimps. These antennas are expected to have areal mass densities of about 2 kg/sq m, satisfying a need for lightweight alternatives to conventional rigid phased-array antennas, which have typical areal mass densities between 8 and 15 kg/sq m. The differences in areal mass densities translate to substantial differences in total mass in contemplated applications involving aperture areas as large as 400 sq m. A membrane phased-array antenna includes patch antenna elements in a repeating pattern. All previously reported membrane antennas were passive antennas; this is the first active membrane antenna that includes transmitting/receiving (T/R) electronic circuits as integral parts. Other integral parts of the antenna include a network of radio-frequency (RF) feed lines (more specifically, a corporate feed network) and of bias and control lines, all in the form of flexible copper strip conductors on flexible polymeric membranes. Each unit cell of a prototype antenna (see Figure 1) contains a patch antenna element and a compact T/R module that is compatible with flexible membrane circuitry. There are two membrane layers separated by a 12.7-mm air gap. Each membrane layer is made from a commercially available flexible circuit material that, as supplied, comprises a 127-micron-thick polyimide dielectric layer clad on both sides with 17.5-micron-thick copper layers. The copper layers are patterned into RF, bias, and control conductors. The T/R module is located on the back side of the ground plane and is RF-coupled to the patch element via a slot. The T/R module is a hybrid multilayer module assembled and packaged independently and attached to the membrane array. At the time of reporting the information for

  16. Numerical simulation of microwave pulse coupling into the rectangular cavity with aperture arrays

    International Nuclear Information System (INIS)

    Li Rui; Yang Yiming; Qian Baoliang

    2008-01-01

    In this paper, the finite-difference time-domain (FDTD) algorithm is employed to simulate microwave pulse coupling into the rectangular cavity with aperture arrays. In the case in which the long-side of the slot in aperture arrays is perpendicular to the incident electrical field, and the electrical distribution of each center of slot in the aperture arrays in the process of microwave pulse coupling into the rectangular cavity with aperture arrays is analyzed in detail. We find that the effect of field enhancement of the slot in the middle of all the slots which distribute in the direction parallel to the incident electrical field is minimum and increases in turn from the middle to both sides symmetrically. We also find that the effect of field enhancement of the slot in the middle of all the slots which distribute in the direction perpendicular to the incident electrical field is maximum and decreases in turn from the middle to both sides symmetrically. In the same time, we investigate the factors that influence the effect of field enhancement of the center of each slot and the coupling electrical distribution in the cavity, including the number of slots and the spacing between slots. (authors)

  17. A new method for the design of slot antenna arrays: Theory and experiment

    KAUST Repository

    Clauzier, Sebastien

    2016-04-10

    The present paper proposes and validates a new general design methodology that can be used to automatically find proper positions and orientations of waveguide-based radiating slots capable of realizing any given radiation beam profile. The new technique combines basic radiation theory and waveguide propagation theory in a novel analytical model that allows the prediction of the radiation characteristics of generic slots without the need to perform full-wave numerical solution. The analytical model is then used to implement a low-cost objective function within a global optimization scheme (here genetic algorithm.) The algorithm is then deployed to find optimum positions and orientations of clusters of radiating slots cut into the waveguide surface such that any desired beam pattern can be obtained. The method is verified using both full-wave numerical solution and experiment.

  18. Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity

    KAUST Repository

    Saeed, A.; Panaro, S.; Zaccaria, R. Proietti; Raja, W.; Liberale, Carlo; Dipalo, M.; Messina, G. C.; Wang, H.; De Angelis, F.; Toma, A.

    2015-01-01

    The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding. © 2015, Nature Publishing Group. All rights reserved.

  19. Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity

    KAUST Repository

    Saeed, A.

    2015-06-09

    The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding. © 2015, Nature Publishing Group. All rights reserved.

  20. Low-Cost and High-Gain SIW Circularly Polarized Circular-Horn-Loaded Antenna for Broadband Millimeter-Wave Applications

    Directory of Open Access Journals (Sweden)

    Ming Du

    2017-09-01

    Full Text Available A wideband, low-cost and high-gain circularly polarized (CP circular-horn-loaded antenna based on substrate integrated waveguide (SIW technology operating at Ka band is presented. The proposed antenna, which is built on a single-layer substrate, consists of five parts: a short-ended SIW, a centro-symmetric wide slot, an L-shaped probe, a circular horn and a transition from SIW to air-filled rectangular waveguide for measurement. The slot is etched on the upper ground of the SIW, while the L-shaped probe for generating CP wave is printed inside the slot and connected to the SIW. A circular horn is also loaded on the surface of the SIW slot for high gain. Then, the proposed antenna with a dimension of 45×45×24.16 mm3 was fabricated and measured. The measured results show that the antenna has a wide impedance matching bandwidth of 28.6% from 30 to 40 GHz for |S11| ≤10 dB and a wide axial ratio (AR bandwidth of 22.8% from 31.5 to 39.6 GHz for AR ≤ 3 dB. The measured maximum gain is 15.6 dBi at 36 GHz with slight fluctuations over the 30–40-GHz frequency range. This kind of antenna merits low cost and easy integration with common differential circuits at the same time.

  1. Design and implementation of low profile antenna for dual-band applications using rotated e-shaped conductor-backed plane.

    Science.gov (United States)

    Jalali, Mahdi; Sedghi, Tohid; Shafei, Shahin

    2014-01-01

    A novel configuration of a printed monopole antenna with a very compact size for satisfying WLAN operations at the 5.2/5.8 GHz and also for X-band operations at the 10 GHz has been proposed. The antenna includes a simple square-shaped patch as the radiator, the rotated U-shaped conductor back plane element with embedded strip on it, and the partial rectangular ground surface. By using the rotated U-shaped conductor-backed plane with proper values, good impedance matching and improvement in bandwidth can be achieved, at the lower and upper bands. The impedance bandwidth for S11 WLAN-band and 4.2 dBi at X-band. The experimental results represent that the realized antenna with good omnidirectional radiation characteristics, enough impedance bandwidth, and reasonable gains can be appropriate for various applications of the future developed technologies and handheld devices.

  2. Novel Wideband Metallic Patch Antennas with Low Profile

    Directory of Open Access Journals (Sweden)

    Zhong-Xiang Zhang

    2017-01-01

    Full Text Available Two planar metallic patch (MP antennas with low profiles are investigated and compared in this paper. The MP of each antenna consists of metallic patch cells and it is centrally fed by a rectangular slot. Two modes with close resonance frequencies are excited, providing a quite wide bandwidth. The antenna principle is explained clearly through a parametric study. Simulated and measured results show that the MP antennas with profile of 0.06λ0 can obtain a 10 dB impedance bandwidth of ~32% and an average gain of ~10 dBi.

  3. Cogging Torque Reduction by Slot-Opening Shift for Permanent Magnet Machines

    DEFF Research Database (Denmark)

    Liu, Ting; Huang, Shoudao; Gao, Jian

    2013-01-01

    In this paper, an effective cogging torque reduction method based on shifting the slot-openings is presented. Stator teeth are divided into groups and proper slot-opening shift is applied for each group. The cogging torque can then be greatly reduced while the back-EMF waveforms remain symmetrical...

  4. In-the-Ear Hearing-Instrument Antenna for ISM-Band Body-Centric Ear-to-Ear Communications

    DEFF Research Database (Denmark)

    Yatman, William H.; Larsen, Lauge K; Kvist, Søren Helstrup

    2012-01-01

    A compact 2.45 GHz slot-loop antenna is implemented for the use in the outer shell of an in-the-ear (ITE) hearing instrument (HI). The antenna is optimized for high ear-to-ear path gain (jS21j). The antenna simulation results are presented for two identical antennas, one placed in the center of e...

  5. Highly Sensitive Reentrant Cavity-Microstrip Patch Antenna Integrated Wireless Passive Pressure Sensor for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Fei Lu

    2017-01-01

    Full Text Available A novel reentrant cavity-microstrip patch antenna integrated wireless passive pressure sensor was proposed in this paper for high temperature applications. The reentrant cavity was analyzed from aspects of distributed model and equivalent lumped circuit model, on the basis of which an optimal sensor structure integrated with a rectangular microstrip patch antenna was proposed to better transmit/receive wireless signals. In this paper, the proposed sensor was fabricated with high temperature resistant alumina ceramic and silver metalization with weld sealing, and it was measured in a hermetic metal tank with nitrogen pressure loading. It was verified that the sensor was highly sensitive, keeping stable performance up to 300 kPa with an average sensitivity of 981.8 kHz/kPa at temperature 25°C, while, for high temperature measurement, the sensor can operate properly under pressure of 60–120 kPa in the temperature range of 25–300°C with maximum pressure sensitivity of 179.2 kHz/kPa. In practical application, the proposed sensor is used in a method called table lookup with a maximum error of 5.78%.

  6. Design of modified pentagonal patch antenna on defective ground for Wi-Max/WLAN application

    Science.gov (United States)

    Rawat, Sanyog; Sharma, K. K.

    2016-04-01

    This paper presents the design and performance of a modified pentagonal patch antenna with defective ground plane. A pentagonal slot is inserted in the pentagonal patch and slot loaded ground through optimized dimensions is used in the antenna to resonate it at dual frequency. The geometry operates at two resonant frequencies (2.5 GHz and 5.58 GHz) and offers impedance bandwidth of 864 MHz and 554 MHz in the two bands of interest. The proposed antenna covers the lower band (2.45 to 2.484/2.495 to 2.695 GHz) and upper band (5.15 to 5.825 GHz/5.25 to 5.85 GHz) allocated for Wi-Max and WLAN communication systems.

  7. Evaluation of slot-to-slot coupling between dielectric slot waveguides and metal-insulator-metal slot waveguides.

    Science.gov (United States)

    Kong, Deqing; Tsubokawa, Makoto

    2015-07-27

    We numerically analyzed the power-coupling characteristics between a high-index-contrast dielectric slot waveguide and a metal-insulator-metal (MIM) plasmonic slot waveguide as functions of structural parameters. Couplings due mainly to the transfer of evanescent components in two waveguides generated high transmission efficiencies of 62% when the slot widths of the two waveguides were the same and 73% when the waveguides were optimized by slightly different widths. The maximum transmission efficiency in the slot-to-slot coupling was about 10% higher than that in the coupling between a normal slab waveguide and an MIM waveguide. Large alignment tolerance of the slot-to-slot coupling was also proved. Moreover, a small gap inserted into the interface between two waveguides effectively enhances the transmission efficiency, as in the case of couplings between a normal slab waveguide and an MIM waveguide. In addition, couplings with very wideband transmissions over a wavelength region of a few hundred nanometers were validated.

  8. Novel Cross-Type Network for Wide-Tuning-Range Reconfigurable Multiband Antennas

    Directory of Open Access Journals (Sweden)

    Chieh-Sen Lee

    2014-01-01

    Full Text Available This paper presents a cross-type network design with a novel reconfigurable functionality to realize a tunable multiband antenna. By attaching a reconfigurable network at the feeding port of a broadband antenna, multi-input impedance adjustment enables the production of multimatching operating bands. Each band can be independently controlled by a single component with a considerably wide tuning range and high selectivity. The experiments in this study involved using an ultra-wideband (UWB antenna connected to the proposed cross-type network. The tunable antenna operates in a dual band of fL (1.39 to 2.34 GHz and fH (2.1 to 3.6 GHz with tunable frequency ratios of 168% and 132%, respectively. The average bandwidths at fL and fH are approximately 50 MHz and 148 MHz, respectively, implying narrowband operation. The measured radiation pattern revealed that the tunable antenna exhibits a nearly omnidirectional radiation pattern at both 1.8 and 3.5 GHz. The network circuit architecture can be extended to the multiband function type by adopting this matching approach. The amount of shunt matches determines the number of operation bands.

  9. Slot opening optimization of surface mounted permanent magnet motor for cogging torque reduction

    International Nuclear Information System (INIS)

    Abbaszadeh, K.; Rezaee Alam, F.; Teshnehlab, M.

    2012-01-01

    Highlights: ► The slot opening shift method is an efficient method for cogging torque reduction. ► Using slot opening skew method, the trapezoidal waveform of back-emf is maintained. ► Using the conventional slot skewing, the wave shape of back-emf is sinusoidal. ► The novelty of paper is using of air–gap permeance harmonics as objective function. ► Other novelty of this paper is using the different optimization algorithms. - Abstract: In this paper, slot opening skew method is used for cogging torque reduction. A three layer stator model is considered for a six-pole PM-BLDC motor (a PM-BLDC motor with 18-slots, six-poles and length of 5 cm) and then a 2D dual model is extracted for this 3D slot opening skew model. The angular shifts of slot opening position in the first and third layers than middle layer are considered as optimization parameters. Slot opening shape is optimized by using different optimization algorithms, such as, the response surface methodology (RSM), the genetic algorithm (GA) and the particle swarm optimization (PSO). In order to using of GA and PSO, the analytical relationship is derived for the air–gap permeance function. The optimization results of these algorithms are being consistent with each other and are verified with FEA results. The results show the significant reduction of cogging torque about 77%.

  10. Measurement of the effects of Faraday shields on ICRH antenna coupling

    International Nuclear Information System (INIS)

    Kwon, M.; Thomas, C.E. Jr.; Rettig, C.L.

    1990-01-01

    Compact loop antennas are being applied to several fusion experiments. Although individual configurations vary, all of these antennas generally comprise a current strap in a recessed box and a Faraday shield. The effect of the cross-sectional shape of the current strap on voltage and current levels was measured. In this work the coupling characteristics of cavity antennas that have current straps with the previously evaluated cross-sectional shapes re tested with several Faraday shields. Impedances and relative fields are measured for various combinations of the current strap and Faraday shield. The experiments show that the fractional reduction in the magnetic flux linkage to the plasma resulting from the addition of any particular Faraday shield i virtually independent of the shape of the current strap. This is true in spite of the fact that the same mechanism which is responsible for the reduction in flux is also responsible for a significant redistribution of the antenna current on the current strap. Thus the process of optimizing antennas is reduced to that of separately optimizing the current strap and Faraday shield

  11. A Novel Compact Dual-Polarized Antenna

    Directory of Open Access Journals (Sweden)

    Yong Cheng

    2016-01-01

    Full Text Available A novel compact dual-polarized antenna is proposed. The antenna has a 1.43% impedance bandwidth which is from 1801 MHz to 1827 MHz for return loss larger than 10 dB. The isolation between the two ports is above 28 dB in the bandwidth, and the gain is 6.6 dBi. The proposed antenna not only consists of a full-planar structure, but also is easy to be fabricated for its simple structure. Additionally, a section of slots and slits is cut on the radiation patch to reduce the area of it to 54% compared with the conventional square patch.

  12. Development of high power models of four-slot Annular Coupled Structure

    International Nuclear Information System (INIS)

    Kageyama, T.; Morozumi, Y.; Yoshino, K.; Yamazaki, Y.

    1994-01-01

    A π/2-mode standing-wave linac (f=1.296 GHz) of an Annular Coupled Structure (ACS) has been developed for the 1-GeV proton linac of the Japanese Hadron Project (JHP). This ACS has four coupling slots between accelerating and coupling cells in order to suppress higher order mode mixing with the π/2 coupling mode. High-β(β=v/c=0.78) and low-β(0.52) prototypes were constructed and tested up to each design RF power. Concerning the effect of the coupling slots on the fields of a coupled-cavity linac, it was found that the slot configuration of the side-coupled structure (SCS) tilts the accelerating field. On the other hand, the four-slot configuration of the ACS gives an almost axially symmetric accelerating field to the beam. (author)

  13. Pumping slots: impedances and power losses

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S [Maryland Univ., College Park, MD (United States). Dept. of Physics

    1996-08-01

    Contributions of pumping slots to the beam coupling impedances and power losses in a B-factory ring are considered. While their leading contribution is to the inductive impedance, for high-intensity machines with short bunches like e{sup +}e{sup -} B-factories the real part of the impedance and related loss factors are also important. Using an analytical approach we calculate the coupling impedances and loss factors due to slots in a ring with an arbitrary cross section of the vacuum chamber. Effects of the slot tilt on the beam impedance are also considered, and restrictions on the tilt angle are derived from limitations on the impedance increase. The power leakage through the slots is discussed briefly. The results are applied to the KEK B-factory. (author)

  14. Current-drive on the Versator-II tokamak with a slotted-waveguide fast-wave coupler

    International Nuclear Information System (INIS)

    Colborn, J.A.

    1987-11-01

    A slotted-waveguide fast-wave coupler has been constructed, without dielectric, and used to drive current on the Versator-II tokamak. Up to 35 kW of net microwave power at 2.45 GHz has been radiated into plasmas with 2 x 10 12 cm -3 ≤ mean of n/sub e/ ≤ 1.2 x 10 13 cm -3 and B/sub tor/ ≅ 1.0 T. The launched spectrum had a peak near N/sub parallel/ = -2.0 and a larger peak near N/sub parallel/ = 0.7. Radiating efficiency of the antenna was roughly independent of antenna position except when the antenna was at least 0.2 cm outside the limiter, in which case the radiating efficiency slightly improved as the antenna was moved farther outside. When the coupler was inside the limiter, radiating efficiency improved moderately with increased mean of n/sub e/. Current-drive efficiency was comparable to that of the slow wave and was not affected when the antenna spectrum was reversed; however, no current was driven for mean of n/sub e/ ≤ 2 x 10 12 cm -3 . These results indicate the fast wave was launched, but a substantial part of the power may have been mode-converted to the slow wave, possibly via a downshift in N/sub parallel/, and these slow waves may have been responsible for most of the driven current. Relevant theory for waves in plasma, current-drive efficiency, and coupling of the slotted-waveguide is discussed, the antenna design method is explained, and future work, including the construction of a much-improved probe-fed antenna, is described. 42 refs., 45 figs

  15. Multiband Patch Antenna for Femtocell Application

    Directory of Open Access Journals (Sweden)

    M. R. Zaman

    2014-01-01

    Full Text Available A microstrip patch antenna for multiple LTE (long term evaluation frequency bands for femtocell application is proposed in this paper. Distributed antenna solution (DAS has been introduced in cellular network to achieve homogenous indoor coverage. Femtocell is the latest extension to these solutions. It is a smart solution to both coverage and capacity scales. Femtocell operation in LTE band is occupied by higher frequency bands. For multiband femtocell application, miniature antenna design is quite essential. The antenna proposed here is composed of basic monopole structure with two parasitic elements at both sides of the active element. A rectangular slot is introduced at the ground plane of the proposed antenna. The antenna is designed using ElnoS HK light CCL substrate material of relative permittivity of 9.4, dielectric loss-tangent of 0.003 and thickness of 3 mm. The S11 response of the antenna is shown to have a bandwidth of 1.01 GHz starting from 1.79 GHz to 2.8 GHz. The characteristics of the antenna are analysed using Ansoft HFSS software.

  16. Cross-Layer Design for Two-Way Relaying Networks with Multiple Antennas

    Directory of Open Access Journals (Sweden)

    zhuo wu

    2015-10-01

    Full Text Available In this paper, we developed a cross-layer design for two-way relaying (TWR networks with multiple antennas, where two single antenna source nodes exchange information with the aid of one multiple antenna relay node. The proposed cross-layer design considers adaptive modulation (AM and space-time block coding (STBC at the physical layer with an automatic repeat request (ARQ protocol at the data link layer, in order to maximize the spectral efficiency under specific delay and packet error ratio (PER constraints. An MMSE-interference cancellation (IC receiver is employed at the relay node, to remove the interference in the fist phase of the TWR transmission. The transmission mode is updated for each phase of the TWR transmission on a frame-by-frame basis, to match the time-varying channel conditions and exploit the system performance and throughput gain. Simulation results show that retransmission at the data link layer could alleviate rigorous error-control requirements at the physical layer, and thereby allows higher data transmission. As a result, cross-layer design helps to achieve considerable system spectral efficiency gain for TWR networks, compared to those without cross-layer design.

  17. A Planar UWB Antenna with Switchable Single/Double Band-Rejection Characteristics

    Directory of Open Access Journals (Sweden)

    V. Sharbati

    2016-09-01

    Full Text Available In this Paper, a reconfigurable antenna with capability to operate in the ultrawideband (UWB mode from 2.85 to 14.4 GHz with switchable notch bands of 3.25–4.26 GHz, 5.1–5.9 GHz or 7.1-7.8 GHz, is presented. The proposed antenna has a simple configuration and compact size of 17 × 14 mm2. To make the band-notches, three methods (methods of slot antenna, parasitic patches and backplane structure are used. To achieve the reconfigurability, three PIN diode are placed on the proposed antenna. A PIN diode is inserted over the L-shaped parasitic element and the rectangular patch, another one is placed between the two parasitic elements on the ground plane, and other across the square ring-shaped slot, respectively. Antenna performance can be changed by adjusting the status of the PIN diodes that make the band-notches in applications bands (WLAN, WiMAX/C-band and X-band. Good group delay and monopole-like radiation pattern characteristics are achieved in the frequency band of interest. The antenna performance both by simulation and by experiment indicates that it is suitable and a good candidate for UWB applications.

  18. Miniaturized printed K shaped monopole antenna with truncated ground plane for 2.4/5.2/5.5/5.8 wireless lan applications

    Science.gov (United States)

    Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

    2018-04-01

    A novel truncated ground plane monopole antenna is proposed for wide band wireless local area network (WLAN) applications. The antenna contains a rectangular patch with a rectangular ring, a circular slot and a truncated ground plane printed on opposite sides of a low cost substrate FR4. The operating frequency bands for the antenna are band1 (2.4-2.88 GHz) and band 2 (4.8-6.3 GHz) with ≤ - 10 dB return loss which covers 2.4/5.2/5.5/5.8 GHz WLAN bands. The antenna is compact with overall dimension 26×40×0.8 mmł and with the dimension of patch 16×16×0.8 mm3. The two bands of antenna is obtained by cutting a rectangular ring and a circular slot in the patch and return loss is improved by cutting two rectangular slot in the ground plane. Performance measures of the antenna are shown in terms of return loss, current distribution, radiation pattern and gain. To verify the simulated results, the antenna is also fabricated and tested. The simulated and fabricated results have been found in good agreement.

  19. Wideband dual frequency modified ellipse shaped patch antenna for WLAN/Wi-MAX/UWB application

    Science.gov (United States)

    Jain, P. K.; Jangid, K. G.; R. Sharma, B.; Saxena, V. K.; Bhatnagar, D.

    2018-05-01

    This paper communicates the design and performance of microstrip line fed modified ellipses shaped radiating patch with defected ground structure. Wide impedance bandwidth performance is achieved by applying a pentagonal slot and T slot structure in ground plane. By inserting two semi ellipses shaped ring in ground, we obtained axial ratio bandwidth approx 600 MHz. The proposed antenna is simulated by utilizing CST Microwave Studio simulator 2014. This antenna furnishes wide impedance bandwidth approx. 4.23 GHz, which has spread into two bands 2.45 GHz - 5.73 GHz and 7.22 GHz - 8.17 GHz with nearly flat gain in operating frequency range. This antenna may be proved as a practicable structure for modern wireless communication systems including Wi-MAX, WLAN and lower band of UWB.

  20. Circular patch microstrip array antenna on NiCoAl ferrite substrate in C-band

    International Nuclear Information System (INIS)

    Kumar, Dheeraj; Pourush, P.K.S.

    2010-01-01

    The problem of a 4x4 circular disc array antenna (CDAA) printed on a uniaxially anisotropic ferrite (NiCoAl) substrate is treated. The effect of anisotropy on the resonant frequency of the antenna is investigated. Radiation and scattering characteristics of the antenna with normal magnetic bias field to the direction of wave propagation in the plane of ferrite are described. Calculated result for the radar cross section (RCS) of antenna presented, and it is shown that the peaks in the RCS can be moved with respect to angle of incidence by changing the magnetic bias field. This effect offers a way of minimizing the radar visibility of microstrip antennas and arrays. Results are obtained from cavity modal solutions for a circular patch antenna at its TM 11 mode.

  1. Design Investigation of a Laminated Waveguide Fed Multi-Band DRA for Military Applications

    Science.gov (United States)

    Kumar, Pramod; Dwari, Santanu; Singh, Shailendra; Agrawal, N. K.

    2017-12-01

    In this paper a laminated waveguide fed DR Antenna is investigated. It can use for moderate power military applications. Cylindrical DRA is excited by two closely spaced asymmetric longitudinal slots on the broad wall of the laminated cavity are responsible for producing three different frequency bands. Parametric study of slots has been done with the help of commercial software ANSOFT HFSS. All the bands have sharp rejection. The final model of the antenna is simulated, fabricated and experimentally measured. Measured results are in quite accordant with design results. SIW feeding structures have small losses, moderate power handling capacity, low costs, compact sizes and can be seamlessly integrated with planar circuits. At all the bands 9.76 GHz, 10.53 GHz and 11.8 GHz resonant frequency, the antenna shows 56 MHz, 160 MHz, and 250 MHz impedance bandwidth (for VSWR<2) with 6 dB,6.2 dB and 6.8 dB gain respectively. Simulated and measured results reveal outstanding performance with a cross-polar level of 29 dB lower than that of the co-polar level at 9.76 GHz, the cross-polar level of 32 dB lower than that of the co-polar level at 10.53, GHz, and similarly cross-polar level of 30 dB lower than that of the co-polar level at 11.8 GHz.

  2. Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

    Science.gov (United States)

    Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

    2010-01-01

    High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

  3. A Very Compact and Low Profile UWB Planar Antenna with WLAN Band Rejection

    Directory of Open Access Journals (Sweden)

    Avez Syed

    2016-01-01

    Full Text Available A low-cost coplanar waveguide fed compact ultrawideband (UWB antenna with band rejection characteristics for wireless local area network (WLAN is proposed. The notch band characteristic is achieved by etching half wavelength C-shaped annular ring slot in the radiating patch. By properly choosing the radius and position of the slot, the notch band can be adjusted and controlled. With an overall size of 18.7 mm × 17.6 mm, the antenna turns out to be one of the smallest UWB antennas with band-notched characteristics. It has a wide fractional bandwidth of 130% (2.9–13.7 GHz with VSWR < 2 and rejecting IEEE 802.11a and HIPERLAN/2 frequency band of 5.1–5.9 GHz. Stable omnidirectional radiation patterns in the H plane with an average gain of 4.4 dBi are obtained. The band-notch mechanism of the proposed antenna is examined by HFSS simulator. A good agreement is found between measured and simulated results indicating that the proposed antenna is well suited for integration into portable devices for UWB applications.

  4. On network representations of antennas inside resonating environments

    Directory of Open Access Journals (Sweden)

    F. Gronwald

    2007-06-01

    Full Text Available We discuss network representations of dipole antennas within electromagnetic cavities. It is pointed out that for a given configuration these representations are not unique. For an efficient evaluation a network representation should be chosen such that it involves as few network elements as possible. The field theoretical analogue of this circumstance is the possibility to express electromagnetic cavities' Green's functions by representations which exhibit different convergence properties. An explicit example of a dipole antenna within a rectangular cavity clarifies the corresponding interrelation between network theory and electromagnetic field theory. As an application, current spectra are calculated for the case that the antenna is nonlinearly loaded and subject to a two-tone excitation.

  5. Bandwidth enhancement of monopole antenna with DGS for SHF and reconfigurable structure for WiMAX, WLAN and C-band applications

    Science.gov (United States)

    Beigi, P.; Mohammadi, P.

    2017-11-01

    In this study a reconfigurable antenna for WiMAX, WLAN, C-bands and SHF applications has been presented. The main body of antenna includes rectangular and L-shaped slotted ground plane and a rectangular patch with slotted feed line, for impedance bandwidth enhancement. In the proposed antenna, a PIN diode is used to adjust the frequency band to SHF, WiMAX, WLAN and C-bands applications. When PIN diode is forward-biased, the antenna covers the 3.5-31 GHz frequency range (i.e. a 160% bandwidth) and when the PIN diode is in its off-state, it operates between 3.4-5.8 GHz. The designed antenna, with a very small size of 12 × 18 × 1.6 mm3, has been fabricated and tested. The radiation pattern is approximately omnidirectional. Simulations and experimental results are in a good agreement with each other and suggest good performance for the presented antenna.

  6. A Butterfly-Shaped Wideband Microstrip Patch Antenna for Wireless Communication

    Directory of Open Access Journals (Sweden)

    Liling Sun

    2015-01-01

    Full Text Available A novel butterfly-shaped patch antenna for wireless communication is introduced in this paper. The antenna is designed for wideband wireless communications and radio-frequency identification (RFID systems. Two symmetrical quasi-circular arms and two symmetrical round holes are incorporated into the patch of a microstrip antenna to expand its bandwidth. The diameter and position of the circular slots are optimized to achieve a wide bandwidth. The validity of the design concept is demonstrated by means of a prototype having a bandwidth of about 40.1%. The return loss of the butterfly-shaped antenna is greater than 10 dB between 4.15 and 6.36 GHz. The antenna can serve simultaneously most of the modern wireless communication standards.

  7. A New Generation of Antenna Structures Based on Novel Composite Materials

    National Research Council Canada - National Science Library

    Katehi, Linda

    1999-01-01

    ... of. In this study, we load a slot ring radiator with a finite dielectric lens, which increases the propagation constant around the antenna as well as over its aperture and therefore relaxes the size requirement...

  8. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    International Nuclear Information System (INIS)

    Solis, S E; Rodriguez, A O; Wang, R; Tomasi, D

    2011-01-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  9. A multi-slot surface coil for MRI of dual-rat imaging at 4T

    Energy Technology Data Exchange (ETDEWEB)

    Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

    2011-07-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  10. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    Energy Technology Data Exchange (ETDEWEB)

    Solis, S E; Rodriguez, A O [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Wang, R; Tomasi, D, E-mail: arog@xanum.uam.mx [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-06-21

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  11. Orthogonal Coupling in Cavity BPM with Slots

    CERN Document Server

    Lipka, D; Siemens, M; Vilcins, S; Caspers, Friedhelm; Stadler, M; Treyer, DM; Maesaka, H; Shintake, T

    2009-01-01

    XFELs require high precision orbit control in their long undulator sections. Due to the pulsed operation of drive linacs the high precision has to be reached by single bunch measurements. So far only cavity BPMs achieve the required performance and will be used at the European XFEL, one between each of the up to 116 undulators. Coupling between the orthogonal planes limits the performance of beam position measurements. A first prototype build at DESY shows a coupling between orthogonal planes of about -20 dB, but the requirement is lower than -40 dB (1%). The next generation cavity BPM was build with tighter tolerances and mechanical changes, the orthogonal coupling is measured to be lower than -43 dB. This report discusses the various observations, measurements and improvements which were done.

  12. Proceedings of the 1989 Antenna Applications Symposium. Volume 2

    Science.gov (United States)

    1990-03-01

    Utilizing Closely 283 Spaced Printed Circuit Flared Slot Antenna Elements for Active Transmit and Receive Phased Array Demonstration," Mark J. Povinelli ...Notch Array, Mark J. Povinelli and John D’Angelo 19. "EHF Active Array, Joe Kobus 343 20. "Unique Joint Stars Phased-Array Antenna," H. Shnitkin 360 iv...Anten..as Propagat., vol. AP-33, pp. 1392-1400, Dec. 1985. [4] M. J. Povinelli and J. A. Johnson, "Design and performance of wideband, dual polarized

  13. Textile antenna integrated with compact AMC and parasitic elements for WLAN/WBAN applications

    Science.gov (United States)

    Lago, Herwansyah; Soh, Ping Jack; Jamlos, Mohd Faizal; Shohaimi, Nursuriati; Yan, Sen; Vandenbosch, Guy A. E.

    2016-12-01

    A wearable antenna fully designed and fabricated using textile is presented. Both antenna and artificial magnetic conductor plane are designed for operation in the wireless local area network (WLAN)/wireless body area network (WBAN) band from 2.4 to 2.5 GHz. The AMC unit element is designed based on the rectangular patch structure, which is then integrated using slots and slits for bandwidth broadening. Meanwhile, the combination of the slits and L-shaped parasitic elements applied at four edges of the rectangular antenna structure enabled unidirectional radiation outwards from the body. The structure is coaxially fed using a rectangular ring slot centered on the radiating element. Simulated and measured reflection and radiation performance indicate a satisfactory agreement, fulfilling the requirements for WLAN/WBAN applications both in free space and on body. The shielding effectiveness provided by the AMC plane is also evaluated numerically in terms of specific absorption rate, indicating levels below the European regulatory limit of 2 W/kg.

  14. Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system

    Directory of Open Access Journals (Sweden)

    Chen Changjun

    2009-11-01

    Full Text Available The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to observe the fl ow pattern through a number of vertically oriented gating systems. The investigation discovers that there are many infl uencing factors on the mold fi lling process. This paper focuses its research on some of the factors, such as the dimensions of the vertical riser and slot thickness, as well as roughness of the coating layer. The results indicate that molten metal can smoothly fi ll into casting cavity with a proper slot gating system. A bigger vertical riser, proper slot thickness and rougher coating can provide not only a better mold fi lling pattern, but also hot melt into the top of the cavity. A proper temperature gradient is obtainable, higher at the bottom and lower at the top of the casting cavity, which is in favor of feeding during casting solidifi cation.

  15. Antenna Array Construction on a Mobile Terminal Chassis at 3.5 GHz for LTE Advanced

    DEFF Research Database (Denmark)

    Syrytsin, Igor A.; Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    This paper proposes a method of constructing an antenna array on the typical ground plane of the modern mobile terminal. An IFA and a slot in a metal frame antenna elements have been used to illustrate the proposed method. The radiation pattern of the element is recorded at the chosen number of t...

  16. HFSS Simulation on Cavity Coupling for Axion Detecting Experiment

    CERN Document Server

    Yeo, Beomki

    2015-01-01

    In the resonant cavity experiment, it is vital maximize signal power at detector with the minimized reflection from source. Return loss is minimized when the impedance of source and cavity are matched to each other and this is called impedance matching. Establishing tunable antenna on source is required to get a impedance matching. Geometry and position of antenna is varied depending on the electromagnetic eld of cavity. This research is dedicated to simulation to nd such a proper design of coupling antenna, especially for axion dark matter detecting experiment. HFSS solver was used for the simulation.

  17. Ion Cyclotron Resonant Heating 2 X 1700 loop antenna for the Tandem Mirror Experiment-Upgrade

    International Nuclear Information System (INIS)

    Brooksby, C.A.; Ferguson, S.W.; Molvik, A.W.; Barter, J.

    1986-01-01

    This paper reviews the mechanical design and improvements that have taken place on the loop type ion cyclotron resonance heating (ICRH) antennas that are located in the center cell region of the Tandem Mirror Experiment-Upgrade (TMX-U). A computer code (JASON) was used to design getter-shielded antenna supports that will hold off very high voltages (83 kV, DC) over a small insulator distance (2.25 inches) in a vacuum of 10/sup -5/ Torr. The authors also added corona shields on the ceramic-to-metal joints of the matching network capacitors. The system now operates reliably with peak radio frequency (RF) voltages of 40 kV at 2-to-4- MHz frequency and power levels up to 200 kW. The authors have just installed a new loop antenna in the east part of the central cell where the slot antenna was located. This antenna uses two of the slot's internal coax lines and the external matching network. The feedthroughs designed by Lawrence Livermore National Laboratory (LLNL) were replaced with two high-voltage RF feedthroughs designed by Oak Ridge National Laboratory (ORNL)

  18. Back Radiation Suppression through a Semitransparent Ground Plane for a mm-Wave Patch Antenna

    KAUST Repository

    Klionovski, Kirill

    2017-06-21

    Omnidirectional radiation pattern with minimum backward radiation is highly desirable for base station antennas to minimize the multipath effects. Semitransparent ground planes have been used to reduce the backward radiation, but mostly with complicated non-uniform impedance distribution. In this work, we propose, for the first time, a round semitransparent ground plane of radius 0.8 λ with uniform impedance distribution that can improve the front-to-back ratio of a wideband patch antenna by 11.6 dB as compared to a similar sized metallic ground plane. The value of uniform impedance is obtained through analytical optimization by using asymptotic expressions in the Kirchhoff approximation of the radiation pattern of a toroidal wave scattered by a round semitransparent ground plane. The semitransparent ground plane has been realized using a low-cost carbon paste on a Kapton film. Experimental results match closely with those of simulations and validate the overall concept.

  19. A new method for the design of slot antenna arrays: Theory and experiment

    KAUST Repository

    Clauzier, Sebastien; Mikki, Said M.; Shamim, Atif; Antar, Yahia M. M.

    2016-01-01

    technique combines basic radiation theory and waveguide propagation theory in a novel analytical model that allows the prediction of the radiation characteristics of generic slots without the need to perform full-wave numerical solution. The analytical model

  20. Design and investigation of sectoral circular disc monopole fractal antenna and its backscattering

    Directory of Open Access Journals (Sweden)

    Raj Kumar

    2017-02-01

    Full Text Available This article presents the design of sectoral circular disc fractal antenna. The proposed antenna has been excited using CPW – feed. The measured result of this antenna offers the ultra wideband characteristics from 3.265 GHz to 15.0 GHz. The measured and simulated results are compared and found in good agreement. The impedance match of the antenna throughout the band is improved by incorporating the rectangular slots in the ground plane. The measured radiation patterns of this antenna are nearly omni-directional in H-plane and bidirectional in E-plane. The backscattering of antenna is also discussed and calculated for antenna mode and structural mode scattering. This type of antenna is useful for UWB system, microwave imaging and vehicular radar, precision positioning location.

  1. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    International Nuclear Information System (INIS)

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-01-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S_1_1) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  2. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, Dheeraj, E-mail: dbhardwaj.bit@gmail.com [Department of Physics, BIT-Mesra-Jaipur Campus, Jaipur 302017 (India); Saraswat, Shriti, E-mail: saraswat.srishti@gmail.com; Gulati, Gitansh, E-mail: gitanshgulati@gmail.com; Shekhar, Snehanshu, E-mail: snehanshushekhar.bit@gmail.com; Joshi, Kanika, E-mail: kanika.karesh@gmail.com [Department of Electronics & Communication, BIT-Mesra-Jaipur Campus, Jaipur 302017 (India); Sharma, Komal, E-mail: kbhardwaj18@gmail.com [Department of Physics, Swami Keshvanand Institute of Technology, Jaipur 302017 (India)

    2016-03-09

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S{sub 11}) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  3. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Science.gov (United States)

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-03-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S11) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  4. Reconfigurable Magneto-Electric Dipole Antennas for Base Stations in Modern Wireless Communication Systems

    Directory of Open Access Journals (Sweden)

    Lei Ge

    2018-01-01

    Full Text Available Magneto-electric (ME dipole antennas, with the function of changing the antenna characteristics, such as frequency, polarization, or radiation patterns, are reviewed in this paper. The reconfigurability is achieved by electrically altering the states of diodes or varactors to change the surface currents distributions or reflector size of the antenna. The purpose of the designs is to obtain agile antenna characteristics together with good directive radiation performances, such as low cross-polarization level, high front-to-back ratio, and stable gain. By reconfiguring the antenna capability to support more than one wireless frequency standard, switchable polarizations, or cover tunable areas, the reconfigurable ME dipole antennas are able to switch functionality as the mission changes. Therefore, it can help increase the communication efficiency and reduce the construction cost. This shows very attractive features in base station antennas of modern wireless communication applications.

  5. Substrate optimization for integrated circuit antennas

    OpenAIRE

    Alexopoulos, N. G.; Katehi, P. B.; Rutledge, D. B.

    1982-01-01

    Imaging systems in microwaves, millimeter and submillimeter wave applications employ printed circuit antenna elements. The effect of substrate properties is analyzed in this paper by both reciprocity theorem as well as integral equation approach for infinitesimally short as well as finite length dipole and slot elements. Radiation efficiency and substrate surface wave guidance is studied for practical substrate materials as GaAs, Silicon, Quartz and Duroid.

  6. Back radiation suppression through a semi-transparent round ground plane for a mm-Wave monopole antenna

    KAUST Repository

    Klionovski, Kirill; Farooqui, Muhammad Fahad; Shamim, Atif

    2017-01-01

    Omnidirectional radiation pattern with minimum backward radiation is highly desirable for millimeter-wave telecommunication antennas. In this work, we propose a round, semitransparent ground plane of radius 0.8λ with uniform impedance distribution that can reduce the back radiation of a monopole antenna by 8.8 dB as compared with a similar sized metallic ground plane. The value of uniform impedance is obtained through analytical optimization by using asymptotic expressions in the Kirchhoff approximation of the radiation pattern of a toroidal wave scattered by a round semitransparent ground plane. The semitransparent ground plane has been realized using a low-cost carbon paste on a Kapton film. Experimental results match closely with those of simulations and validate the overall concept.

  7. Back radiation suppression through a semi-transparent round ground plane for a mm-Wave monopole antenna

    KAUST Repository

    Klionovski, Kirill

    2017-10-25

    Omnidirectional radiation pattern with minimum backward radiation is highly desirable for millimeter-wave telecommunication antennas. In this work, we propose a round, semitransparent ground plane of radius 0.8λ with uniform impedance distribution that can reduce the back radiation of a monopole antenna by 8.8 dB as compared with a similar sized metallic ground plane. The value of uniform impedance is obtained through analytical optimization by using asymptotic expressions in the Kirchhoff approximation of the radiation pattern of a toroidal wave scattered by a round semitransparent ground plane. The semitransparent ground plane has been realized using a low-cost carbon paste on a Kapton film. Experimental results match closely with those of simulations and validate the overall concept.

  8. A millimeter-wave connected antenna array for 5G applications

    KAUST Repository

    Ikram, Muhammad; Sharawi, Mohammad S.; Shamim, Atif

    2017-01-01

    In this work, a beam switched antenna system based on a planar connected antenna array (CAA) is proposed at 28 GHz for 5G applications. The antenna system consists of a 4 × 4 connected slot antenna elements. It is covering frequency band from 27.4 GHz to 28.23 GHz with at least −10dB bandwidth of 830 MHz. It is modeled on a commercially available RO3003 substrate with ∊r equal to 3.3. The dimensions of the board are equal to 61×54×0.13 mm3. The proposed design is compact and low profile. A Butler matrix based feed network is used to steer the beam at different locations.

  9. A millimeter-wave connected antenna array for 5G applications

    KAUST Repository

    Ikram, Muhammad

    2017-10-25

    In this work, a beam switched antenna system based on a planar connected antenna array (CAA) is proposed at 28 GHz for 5G applications. The antenna system consists of a 4 × 4 connected slot antenna elements. It is covering frequency band from 27.4 GHz to 28.23 GHz with at least −10dB bandwidth of 830 MHz. It is modeled on a commercially available RO3003 substrate with ∊r equal to 3.3. The dimensions of the board are equal to 61×54×0.13 mm3. The proposed design is compact and low profile. A Butler matrix based feed network is used to steer the beam at different locations.

  10. Eight-Element Antenna Array for LTE 3.4-3.8 GHz Mobile Handset Applications

    Science.gov (United States)

    Yang, Lingsheng; Ji, Ming; Cheng, Biyu; Ni, Bo

    2017-05-01

    In this letter, an eight-element Multiple-input multiple-output (MIMO) antenna system for LTE mobile handset applications is proposed. The antenna array consists of eight 3D inverted F-shaped antennas (3D-IFA), and the measured -10 dB impedance bandwidth is 3.2-3.9 GHz which can cover the LTE bands 42 and 43 (3.4-3.8 GHz). By controlling the rotation of the antenna elements, no less than 10 dB isolation between antenna elements can be obtained. After using the specially designed meandered slots on the ground as decoupling structures, the measured isolation can be further improved to higher than 13 dB between the antenna elements at the whole operating band.

  11. Novel large deployable antenna backing structure concepts for foldable reflectors

    Science.gov (United States)

    Fraux, V.; Lawton, M.; Reveles, J. R.; You, Z.

    2013-12-01

    This paper describes a number of large deployable antenna (LDA) reflector structure concepts developed at EnerSys-ABSL. Furthermore, EnerSys-ABSL has confirmed the desire to build a breadboard demonstrator of a backing deployable structure for a foldable reflector in the diameter range of 4-9 m. As part of this project EnerSys-ABSL has explored five novel deployable structure concepts. This paper presents the top level definition of these concepts together with the requirements considered in the design and selection of the preferred candidate. These new concepts are described and then compared through a trade-off analysis to identify the most suitable concept that EnerSys-ABSL would like to consider for the breadboard demonstrator. Finally, the kinematics of the chosen concept is described in more detail and future steps in the development process are highlighted.

  12. Triple-Notched Band CPW fed UWB Antenna with Metallic Reflector for High Gain Performance

    Directory of Open Access Journals (Sweden)

    K. G. Jangid

    2017-10-01

    Full Text Available This paper exhibits the design and performance of a coplanar waveguide (CPW fed triple notched band ultra-wide band (UWB antenna. Proposed prototype has two U-shaped slots on the patch and an inverted U slot in feed line with a metal reflector beneath the radiating element. Proposed structure renders wider impedance bandwidth extended between frequencies 2.71GHz to 12.92 GHz for VSWR 2. The utmost simulated gain of proposed antenna with reflector is close to 9.9dBi at 7.4GHz. A sharp reduction observed in the efficiency values of the proposed structure at stop bands. Perhaps, this structure proved as a useful tool for various applications in modern communication systems including UWB.

  13. Inkjet-Printed Wideband Antenna on Resin-Coated Paper Substrate for Curved Wireless Devices

    KAUST Repository

    Abutarboush, Hattan; Farooqui, Muhammad Fahad; Shamim, Atif

    2015-01-01

    A low-cost, inkjet-printed multiband monopole antenna for conformal wireless applications is presented for the first time. The antenna is implemented on a low cost resin coated paper substrate which can be used for conformal devices. The antenna developed here is composed of four branch lines on the radiator and three L-shaped slots on the ground plane that help to generate multiple bands without increasing the size of the antenna. The antenna has a compact size, making it suitable for handheld and wearable wireless devices. Details of the inkjet printing fabrication processes and related issues are presented. The antennas were characterized under flat and bent conditions and the results indicate that the antennas can cover most bands for mobile and wireless applications such as PCS, UMTS, GSM1900 and WLAN

  14. Inkjet-Printed Wideband Antenna on Resin-Coated Paper Substrate for Curved Wireless Devices

    KAUST Repository

    Abutarboush, Hattan

    2015-04-28

    A low-cost, inkjet-printed multiband monopole antenna for conformal wireless applications is presented for the first time. The antenna is implemented on a low cost resin coated paper substrate which can be used for conformal devices. The antenna developed here is composed of four branch lines on the radiator and three L-shaped slots on the ground plane that help to generate multiple bands without increasing the size of the antenna. The antenna has a compact size, making it suitable for handheld and wearable wireless devices. Details of the inkjet printing fabrication processes and related issues are presented. The antennas were characterized under flat and bent conditions and the results indicate that the antennas can cover most bands for mobile and wireless applications such as PCS, UMTS, GSM1900 and WLAN

  15. A Simple Ultra-Wideband Magneto-Electric Dipole Antenna With High Gain

    Science.gov (United States)

    Shuai, Chen-yang; Wang, Guang-ming

    2017-12-01

    A simple ultra-wideband magneto-electric dipole antenna utilizing a differential-fed structure is designed. The antenna mainly comprises three parts, including a novel circular horned reflector, two vertical semicircular shorted patches as a magnetic dipole, and a horizontal U-shaped semicircular electric dipole. A differential feeding structure working as a perfect balun excites the designed antenna. The results of simulation have a good match with the ones of measurement. Results indicate that the designed antenna achieves a wide frequency bandwidth of 107 % which is 3.19 10.61 GHz, when VSWR is below 2. Via introducing the circular horned reflector, the designed antenna attains a steady and high gain of 12±1.5dBi. Moreover, settled broadside direction main beam, high front-to-back ratio, low cross polarization, and the symmetrical and relatively stable radiation patterns in the E-and H-plane are gotten in the impedance bandwidth range. In the practical applications, the proposed antenna that is dc grounded and has a simple structure satisfies the requirement of many outdoor antennas.

  16. A New Metasurface Superstrate Structure for Antenna Performance Enhancement.

    Science.gov (United States)

    Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Faruque, Mohammad Rashed Iqbal

    2013-07-31

    A new metasurface superstrate structure (MSS)-loaded dual band microstrip line-fed small patch antenna is presented in this paper. The proposed antenna was designed on a ceramic-filled bioplastic sandwich substrate with a high dielectric constant. The proposed 7 × 6 element, square-shaped, single-sided MSS significantly improved the bandwidth and gain of the proposed antenna. The proposed MSS incorporated a slotted patch antenna that effectively increased the measured operating bandwidth from 13.3% to 18.8% and from 14.8% to 23.2% in the lower and upper bands, respectively. Moreover, the average gain of the proposed MSS-based antenna was enhanced from 2.12 dBi to 3.02 dBi in the lower band and from 4.10 dBi to 5.28 dBi in the upper band compared to the patch antenna alone. In addition to the bandwidth and gain improvements, more directive radiation characteristics were also observed from the MSS antenna compared to the patch itself. The effects of the MSS elements and the ground plane length on the reflection coefficient of the antenna were analyzed and optimized. The overall performance makes the proposed antenna appropriate for RFID and WLAN applications.

  17. High order mode damping in a pill box cavity

    International Nuclear Information System (INIS)

    Voelker, F.; Lambertson, G.; Rimmer, R.

    1991-04-01

    We have substantially damped the higher order modes (HOM's) in a pill box cavity with attached beam pipe, while reducing the Q of the principal mode by less that 10%. This was accomplished by cutting slots in the cavity end wall at a radius at which the magnetic field of the lowest frequency HOM's is large. The slots couple energy from the cavity into waveguides which are below cut off for the principal mode, but which propagate energy at the HOM frequencies. Three slots 120 degrees apart couple HOM energy to three waveguides. We are concerned primarily with accelerating and deflecting modes: i.e. the TM mnp modes of order m=0 and m=1. For the strongest damping, only three m=0 and m=1 modes were detectable. These were the principal TM 010 mode, the TM 011 longitudinal mode, and the TM 110 deflecting mode. In addition the HOM Q's and the reduction of Q for the principal mode were determined by computer calculation. The principal mode Q for an actual rf cavity could not be measured because the bolted joints used in the construction of the cavity were not sufficiently good to support Q's above 6000. The measured Q of the first longitudinal mode was 31 and of the first transverse mode 37. Our maximum damping was limited by how well we could terminated the waveguides, and indeed, the computer calculations for the TM 011 and TM 110 modes give values in the range we measured. 2 refs., 2 figs

  18. Low energy booster radio frequency cavity structural analysis

    International Nuclear Information System (INIS)

    Jones, K.

    1994-01-01

    The structural design of the Superconducting Super Collider Low Energy Booster (LEB) Radio Frequency (RF) Cavity is very unique. The cavity is made of three different materials which all contribute to its structural strength while at the same time providing a good medium for magnetic properties. Its outer conductor is made of thin walled stainless steel which is later copper plated to reduce the electrical losses. Its tuner housing is made of a fiber reinforced composite laminate, similar to G10, glued to stainless steel plating. The stainless steel of the tuner is slotted to significantly diminish the magnetically-induced eddy currents. The composite laminate is bonded to the stainless steel to restore the structural strength that was lost in slotting. The composite laminate is also a barrier against leakage of the pressurized internal ferrite coolant fluid. The cavity's inner conductor, made of copper and stainless steel, is subjected to high heat loads and must be liquid cooled. The requirements of the Cavity are very stringent and driven primarily by deflection, natural frequency and temperature. Therefore, very intricate finite element analysis was used to complement conventional hand analysis in the design of the cavity. Structural testing of the assembled prototype cavity is planned to demonstrate the compliance of the cavity design to all of its requirements

  19. Low energy booster radio frequency cavity structural analysis

    International Nuclear Information System (INIS)

    Jones, K.

    1993-04-01

    The structural design of the Superconducting Super Collider Low Energy Booster (LEB) Radio Frequency (RF) Cavity is very unique. The cavity is made of three different materials which all contribute to its structural strength while at the same time providing a good medium for magnetic properties. Its outer conductor is made of thin walled stainless steel which is later copper plated to reduce the electrical losses. Its tuner housing is made of a fiber reinforced composite laminate, similar to G10, glued to stainless steel plating. The stainless steel of the tuner is slotted to significantly diminish the magnetically-induced eddy currents. The composite laminate is bonded to the stainless steel to restore the structural strength that was lost in slotting. The composite laminate is also a barrier against leakage of the pressurized internal ferrite coolant fluid. The cavity's inner conductor, made of copper and stainless steel, is subjected to high heat loads and must be liquid cooled. The requirements of the Cavity are very stringent and driven primarily by deflection, natural frequency and temperature. Therefore, very intricate finite element analysis was used to complement conventional hand analysis in the design of the cavity. Structural testing of the assembled prototype cavity is planned to demonstrate the compliance of the cavity design to all of its requirements

  20. Slotted Photonic Crystal Sensors

    Science.gov (United States)

    Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

    2013-01-01

    Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

  1. Slotted Photonic Crystal Sensors

    Directory of Open Access Journals (Sweden)

    Andrea Di Falco

    2013-03-01

    Full Text Available Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study.

  2. Compact Modified Swastika Shape Patch Antenna for WLAN/WiMAX Applications

    Directory of Open Access Journals (Sweden)

    M. Samsuzzaman

    2014-01-01

    Full Text Available A compact simple structure modified Swastika shape multiband patch antenna is designed and investigated. The antenna, which occupies an overall dimension of 0.305λ × 0.305λ × 0.012λ at lower frequency, has a simple structure which comprises of a planar wide square slot in the ground with four slits and Swastika shape radiation patch with a rectangular slot. The proposed Swastika shape antenna was designed and analyzed by using a finite element method based high frequency structural simulator HFSS. The experimental and numerical results exhibit that the antenna operates over the frequency ranges 950 MHz (2.28–3.23 GHz, 660 MHz (3.28–3.94 GHz, and 1120 MHz (5.05–6.17 GHz suitable for WLAN (2.4/5.2/5.8 GHz and WiMAX 2.5/3.5/5.5 GHz applications. It has a good omnidirectional radiation pattern and reaches 3.97 dBi at 2.44 GHz, 4.04 dBi at 3.5 GHz, and 3.25 dBi at the band of 5.98 GHz. A prototype is fabricated and then measured. The experimental and simulation results show good impedance bandwidth, radiation pattern, and stable gain across the operating bands.

  3. Analysis of a Waveguide-Fed Metasurface Antenna

    Science.gov (United States)

    Smith, David R.; Yurduseven, Okan; Mancera, Laura Pulido; Bowen, Patrick; Kundtz, Nathan B.

    2017-11-01

    The metasurface concept has emerged as an advantageous reconfigurable antenna architecture for beam forming and wave-front shaping, with applications that include satellite and terrestrial communications, radar, imaging, and wireless power transfer. The metasurface antenna consists of an array of metamaterial elements distributed over an electrically large structure, each subwavelength in dimension and with subwavelength separation between elements. In the antenna configuration we consider, the metasurface is excited by the fields from an attached waveguide. Each metamaterial element can be modeled as a polarizable dipole that couples the waveguide mode to radiation modes. Distinct from the phased array and electronically-scanned-antenna architectures, a dynamic metasurface antenna does not require active phase shifters and amplifiers but rather achieves reconfigurability by shifting the resonance frequency of each individual metamaterial element. We derive the basic properties of a one-dimensional waveguide-fed metasurface antenna in the approximation in which the metamaterial elements do not perturb the waveguide mode and are noninteracting. We derive analytical approximations for the array factors of the one-dimensional antenna, including the effective polarizabilities needed for amplitude-only, phase-only, and binary constraints. Using full-wave numerical simulations, we confirm the analysis, modeling waveguides with slots or complementary metamaterial elements patterned into one of the surfaces.

  4. Dual Band Planar Inverted F Antenna (PIFA with L-Shape Configuration

    Directory of Open Access Journals (Sweden)

    khlouf Munzer Mohamad

    2017-01-01

    Full Text Available One of the most used antennas in mobile devices is planar inverted F antenna (PIFA. PIFA can be design in dual band frequencies due to the coverage of the wireless service in a mobile device that requires a multiple frequencies. However, the consideration of technical operation has to be combined with an evaluation of the antenna radiation impact on the users. A procedure of PIFA work in GSM (867-960MHz and GSM (1710-1899MHz is done using CST Software. The dual band frequency response is obtained by means of an insertion of an L-shaped slot, which is use to tune the operation frequencies. The prototype of the antenna is fabricated as model by CST Software and evaluated. It is found out that the PIFA antenna has a good efficiency, bandwidth as well as produce a maximum gain for the antenna. A key and innovative research is still underway to broaden performance parameters of the antenna.

  5. Study of Nb-Cu 1.3 GHz SRF cavity resonators for future particle accelerators

    CERN Document Server

    Amelin, Kirill

    2017-01-01

    Niobium-coated superconducting radio-frequency cavities have a number of advantages over cavities made from bulk niobium. Cavities coated with high-power impulse magnetron sputtering are tested at CERN in order to optimize the coating and study the Q-slope that limits the performance. To accurately measure the quality factor as a function of accelerating field, it is important to have good matching between an input antenna and a cavity impedance. To improve the matching, a variable coupler that changes the length of the antenna can be used. We have shown that the Q-factor of the input antenna can be changed between $10^7-10^{11}$ by moving the antenna, which should allow to achieve critical coupling with a cavity. This technology could be used in future measurements, so that reflections are always minimized.

  6. FEM Analysis of Brushless DC Servomotor with Fractional Number of Slots per Pole

    Directory of Open Access Journals (Sweden)

    BALUTA, G.

    2014-02-01

    Full Text Available The authors present in this paper the analysis with Finite Element Method (FEM of the magnetic circuit for a Brushless DC servomotor with fractional number of slots/pole (9 slots and 10 poles. For this purpose, FEMM 4.2 software package was used for the analysis. To obtain the waveforms of Back-ElectroMotive Forces (BEMFs, electromagnetic and cogging torque for servomotor a program in LUA scripting language (integrated into interactive shell of FEMM4.2 has been created. A comparation with a structure with integer number of slots/pole (18 slots and 6 poles was also realized. The analysis results prove that the structure chosen is an optimal solution: sinusoidal waveforms of BEMFs, improved electromagnetic torque and reduced cogging torque. Therefore, the operating characteristics of the servomotor with 9/10 slots/poles manufactured by Sistem Euroteh Company and included in an integrated electrical drives system are presented in this paper.

  7. A Novel Planar Fractal Antenna with CPW-Feed for Multiband applications

    Directory of Open Access Journals (Sweden)

    S. Joseph

    2013-12-01

    Full Text Available In this paper, a multiband antenna using a novel fractal design is presented. The antenna structure is formed by inscribing a hexagonal slot within a circle. This base structure is then scaled and arranged within the hexagon along its sides without touching the outer structure. The proposed CPW fed, low profile antenna offers good performance in the 1.65-2.59 GHz, 4.16-4.52 GHz and 5.54-6.42 GHz bands and is suitable for GSM 1800/1900, Bluetooth, IMT advanced system and upper WLAN applications. The antenna has been fabricated on a substrate of height 1.6mm and er=4.4 and simulation and experimental results are found to be in good agreement.

  8. New electrodynamic and electrostatic models with applications to antenna theory, superconductor slots, and lasers

    International Nuclear Information System (INIS)

    Eggleston, S.W.

    1988-01-01

    The common set of functions used as a basis for the solution to Helmholtz and Laplace's equations is expanded to include solutions not found in the handbooks. With this complete set of basis functions of integer indexes, a multicentered model is developed using Debye-like potentials for electrodynamics and standard potentials for electrostatics. The resonant modes of the model are the exact solution to a wide variety of thin linear antennas and antenna-like structures, narrow linear gaps in superconductors, microscopic linear lasers, and arbitrary linear charge distributions. The model is applied to a linear antenna of large-diameter, via Pocklington's and Hallen's integral equation. The nonsinusoidal current of this linear antenna of large-diameter is decomposed into idealized components using equal and unequal spacing, and single and many centered linear antennas. Babinet's principal is brought into play to apply the model to gaps in superconductors. The model of a laser is in the microscopic domain, a domain that has not been looked at previously. The electrostatic model allows the modeling of an arbitrary linear charge distribution between two points

  9. User's manual for CBS3DS, version 1.0

    Science.gov (United States)

    Reddy, C. J.; Deshpande, M. D.

    1995-10-01

    CBS3DS is a computer code written in FORTRAN 77 to compute the backscattering radar cross section of cavity backed apertures in infinite ground plane and slots in thick infinite ground plane. CBS3DS implements the hybrid Finite Element Method (FEM) and Method of Moments (MoM) techniques. This code uses the tetrahedral elements, with vector edge basis functions for FEM in the volume of the cavity/slot and the triangular elements with the basis functions for MoM at the apertures. By virtue of FEM, this code can handle any arbitrarily shaped three-dimensional cavities filled with inhomogeneous lossy materials; due to MoM, the apertures can be of any arbitrary shape. The User's Manual is written to make the user acquainted with the operation of the code. The user is assumed to be familiar with the FORTRAN 77 language and the operating environment of the computer the code is intended to run.

  10. Mobile applications of photovoltaic planar antennas - SOLPLANT {sup registered}; Mobile Anwendungen von Solaren Planarantennen - SOLPLANT {sup registered}

    Energy Technology Data Exchange (ETDEWEB)

    Bendel, C.; Kirchhof, J. [Institut fuer Solare Energieversorgungstechnik (ISET), Kassel (Germany); Henze, N. [Kassel Univ. (Gesamthochschule) (Germany). Fachgebiet Hochfrequenztechnik

    2005-07-01

    This paper describes the application of photovoltaic (PV) Solar Planar Antennas in mobile applications. The radiating patch element of a planar antenna is replaced by a solar cell. Furthermore radiating slots can be built due to the cell spacing in a solar cell array. The original feature of a solar cell (DC current generation) remains, but additionally the solar cell is now able to receive and transmit electromagnetic waves. Both single solar cells as well as solar cell arrays can be used as antennas. This new approach, the ''Solar Planar Antenna - SOLPLANT {sup registered} '', avoids disadvantages of conventional applications, when solar cells and antennas are used in combination. Based on these considerations, a product development concept was originated at whose basic idea has been registered as a patent in Germany, Europe, Japan and USA. Four applications are presented: a solar cell GPS antenna for vehicular applications, a solar cell slot antenna for mobile communications (GSM), an environmental metering station with GSM function and a Worldspace Satellite Radio, equipped with a SOLPLANT {sup registered} antenna. The aim of the first two products is to integrate these antennas into vehicular glass roofs which are covered with photovoltaic solar cells in order to deliver the electric power for the indoor ventilation of the car. The GPS antenna provides circular polarisation and a main lobe in zenith direction whereas the GSM antenna is vertically polarized and has a monopole-like radiation pattern. Both antennas are built up with commonly used solar cells. The comparison of measured and simulated antenna properties shows a good agreement. At last, some applications on high altitude platforms for wireless communication services and remote sensing are depicted. (ORIG.)

  11. Microwave Backscatter-Based Wireless Temperature Sensor Fabricated by an Alumina-Backed Au Slot Radiation Patch.

    Science.gov (United States)

    Lu, Fei; Wang, Haixing; Guo, Yanjie; Tan, Qiulin; Zhang, Wendong; Xiong, Jijun

    2018-01-16

    A wireless and passive temperature sensor operating up to 800 °C is proposed. The sensor is based on microwave backscatter RFID (radio frequency identification) technology. A thin-film planar structure and simple working principle make the sensor easy to operate under high temperature. In this paper, the proposed high temperature sensor was designed, fabricated, and characterized. Here the 99% alumina ceramic with a dimension of 40 mm × 40 mm × 1 mm was prepared in micromechanics for fabrication of the sensor substrate. The metallization of the Au slot patch was realized in magnetron sputtering with a slot width of 2 mm and a slot length of 32 mm. The measured resonant frequency of the sensor at 25 °C is 2.31 GHz. It was concluded that the resonant frequency decreases with the increase in the temperature in range of 25-800 °C. It was shown that the average sensor sensitivity is 101.94 kHz/°C.

  12. Analysis and Design of a Novel Multiband Antenna for Mobile Terminals

    Directory of Open Access Journals (Sweden)

    Yuan Yao

    2015-01-01

    Full Text Available A multiband planar terminal antenna with a compact size of 40 mm × 24 mm is proposed in this paper. This antenna consists of a monopole patch with two slots on it and a meandering strip loaded on the top. Two parasitic stubs and a branch on the ground are used to adjust and widen the impedance bandwidth of the antenna. Simulations and measurements are carried out to study the antenna performances in terms of impedance matching, efficiency, gain, and radiation patterns. Both of simulation and measurement results are shown to illustrate the good performance of the proposed antenna. The antenna can operate at 450–474 MHz, 860–1040 MHz, 1705–2428 MHz, and 2500–2710 MHz. These operating bandwidths cover GSM900, DCS, PCS, UMTS, LTE2500, and LTE’s low frequency band (450–470 MHz. It is very suitable for multifunctional terminal applications in wireless communication systems.

  13. Design of Compact Flower Shape Dual Notched-Band Monopole Antenna for Extended UWB Wireless Applications

    Science.gov (United States)

    Sharma, Manish; Awasthi, Y. K.; Singh, Himanshu; Kumar, Raj; Kumari, Sarita

    2016-11-01

    In this letter, a compact monopole antenna for ultra wideband (UWB) applications is proposed with small size of 18×20=360 mm2. Antenna consist of a flower shape radiating patch with a pair of C-shaped slots which offer two notch bands for WiMAX (3.04-3.68 GHz) & WLAN (4.73-5.76 GHz) and two rectangular shaped slots in the ground plane which provides a wide measured usable fractional extended bandwidth of 163 % (2.83-14.0 GHz) with improved VSWR. Moreover, it is also convenient for other wireless application as close range radar, 8-12 GHz in X-band. Measured radiation patterns exhibits nearly omnidirectional in H-plane and dipole like pattern in E-plane across the bandwidth and furthermore exhibits good time domain performance.

  14. A Low Profile Ultrawide Band Monopole Antenna for Wearable Applications

    Directory of Open Access Journals (Sweden)

    Srinivas Doddipalli

    2017-01-01

    Full Text Available A low profile pentagonal shaped monopole antenna is designed and presented for wearable applications. The main objective of this paper is to design a miniaturized ultrawide band monopole planar antenna which can work efficiently in free space but also on the surface of the human body. The impact of human tissues on antenna performance is explained using the proposed pentagonal monopole antenna. The antenna is designed with a pentagonal radiator and a matched feed line of 50 ohm and square slots are integrated on defected ground of FR4 substrate with a size of 15 mm × 25 mm to achieve ultrawide band (UWB performance in free space and human proximity. This overall design will enhance the antenna performance with wide bandwidth ranging from 2.9 GHz to 11 GHz. Specific absorption rate (SAR of the proposed antenna on dispersive phantom model is also measured to observe the exposure of electromagnetic energy on human tissues. The simulated and measured results of the proposed antenna exhibit wide bandwidth and radiation characteristics in both free space and human proximity.

  15. Transport Infrastructure Slot Allocation

    NARCIS (Netherlands)

    Koolstra, K.

    2005-01-01

    In this thesis, transport infrastructure slot allocation has been studied, focusing on selection slot allocation, i.e. on longer-term slot allocation decisions determining the traffic patterns served by infrastructure bottlenecks, rather than timetable-related slot allocation problems. The

  16. Impedance matching of a coaxial antenna for microwave in-situ processing of polluted soils.

    Science.gov (United States)

    Pauli, Mario; Kayser, Thorsten; Wiesbeck, Werner; Komarov, Vyacheslav

    2011-01-01

    The present paper is focused on the minimization of return loss of a slotted coaxial radiator proposed for a decontamination system for soils contaminated by volatile or semi-volatile organic compounds such as oils or fuels. The antenna upgrade is achieved by coating it with a 5 mm thick Teflon layer. The electromagnetic characteristics reflection coefficient and power density distribution around the antenna surrounded by soils with different moisture levels are analyzed numerically. Simplified analytical approaches are employed to accelerate the optimization of the given antenna for microwave heating systems. The improved antenna design shows a good matching of the antenna to the surrounding soil with varying moisture levels. This ensures a high efficiency of the proposed in-situ soil decontamination system.

  17. Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

    International Nuclear Information System (INIS)

    Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

    2008-01-01

    Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging

  18. 3-D analysis of Maxwell's equations for cavities of arbitrary shape

    International Nuclear Information System (INIS)

    Whealton, J.H.; Chen, G.L.; McGaffey, R.W.; Raridon, R.J.; Jaeger, E.F.; Bell, M.A.; Hoffman, D.J.

    1986-03-01

    A three-dimensional analysis of cavity antennas is presented. The analysis is based on the finite difference method with a successive overrelaxation convergence scheme. This method permits the calculation of resonance frequencies and corresponding electric and magnetic fields of eigenmodes in a cavity antenna with an arbitrary shape. 12 refs., 8 figs

  19. Some remarks on antenna response in a reverberation chamber

    Energy Technology Data Exchange (ETDEWEB)

    WARNE,LARRY K.; LEE,K.S.H.

    2000-03-15

    The simple formula, {l_angle}P{sub r}{r_angle}=(E{sub o}{sup 2}/{eta})({lambda}{sup 2}/8{pi}), for the received power of an antenna with a matched load in an over-moded cavity actually holds for an antenna of any shape and size. This can be seen from the close connection between the correlation tensor of the cavity field at two different points and the imaginary part of the free-space dyadic Green's function.

  20. A Minkowski Fractal Circularly Polarized Antenna for RFID Reader

    Directory of Open Access Journals (Sweden)

    Yanzhong Yu

    2014-11-01

    Full Text Available A design of fractal-like antenna with circular polarization for radio frequency identification (RFID reader applications is presented in this article. The modified Minkowski fractal structure is adopted as radiating patch for size reduction and broadband operation. A corner-truncated technology and a slot-opened method are employed to realize circular polarization and improve the gain of the proposed antenna, respectively. The proposed antenna is analyzed and optimized by HFSS. Return loss and maximum gain of the optimized antenna achieve to -22.2 dB and 1.12 dB at 920 MHz, respectively. The optimized design has an axial ratio (AR of 1.2 dB at central frequency of 920 MHz and impedance bandwidth (S11<=-10 dB of 40 MHz (4.3 %. Its input impedance is (57.9-j2.6 W that is close to input impedance of coaxial line (50 W. Numerical results demonstrate that the optimized antenna exhibits acceptable performances and may satisfy requirements of RFID reader applications.

  1. An efficient fringe integral equation method for optimizing the antenna location on complex bodies

    DEFF Research Database (Denmark)

    Jørgensen, Erik; Meincke, Peter; Breinbjerg, Olav

    2001-01-01

    The radiation pattern of an antenna mounted nearby, or directly on, a complex three-dimensional (3D) structure can be significantly influenced by this structure. Integral equations combined with the method of moments (MoM) provide an accurate means for calculating the scattering from the structures...... in such applications. The structure is then modelled by triangular or rectangular surface patches with corresponding surface current expansion functions. A MoM matrix which is independent of the antenna location can be obtained by modelling the antenna as an impressed electric or magnetic source, e.g., a slot antenna...... can be modelled by a magnetic Hertzian dipole. For flush-mounted antennas, or antennas mounted in close vicinity of the scattering structure, the nearby impressed source induces a highly peaked surface current on the scattering structure. For the low-order basis functions usually applied...

  2. The Role of Auditory Features Within Slot-Themed Social Casino Games and Online Slot Machine Games.

    Science.gov (United States)

    Bramley, Stephanie; Gainsbury, Sally M

    2015-12-01

    Over the last few years playing social casino games has become a popular entertainment activity. Social casino games are offered via social media platforms and mobile apps and resemble gambling activities. However, social casino games are not classified as gambling as they can be played for free, outcomes may not be determined by chance, and players receive no monetary payouts. Social casino games appear to be somewhat similar to online gambling activities in terms of their visual and auditory features, but to date little research has investigated the cross over between these games. This study examines the auditory features of slot-themed social casino games and online slot machine games using a case study design. An example of each game type was played on three separate occasions during which, the auditory features (i.e., music, speech, sound effects, and the absence of sound) within the games were logged. The online slot-themed game was played in demo mode. This is the first study to provide a qualitative account of the role of auditory features within a slot-themed social casino game and an online slot machine game. Our results found many similarities between how sound is utilised within the two games. Therefore the sounds within these games may serve functions including: setting the scene for gaming, creating an image, demarcating space, interacting with visual features, prompting players to act, communicating achievements to players, providing reinforcement, heightening player emotions and the gaming experience. As a result this may reduce the ability of players to make a clear distinction between these two activities, which may facilitate migration between games.

  3. Metamaterial-Backed Conformal Antennas for Space Exploration

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this experiment is to demonstrate a successful X-band antenna array fabricated on a high-permittivity substrate together with bandgap metamaterials...

  4. Application of the modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas in complex environment

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    In this paper, application of a modified Wheeler cap method for the radiation efficiency measurement of balanced electrically small antennas is presented. It is shown that the limitations on the cavity dimension can be overcome and thus measurement in a large cavity is possible. The cavity loss...... is investigated, and a modified radiation efficiency formula that includes the cavity loss is introduced. Moreover, a modification of the technique is proposed that involves the antenna working complex environment inside the Wheeler Cap and thus makes possible measurement of an antenna close to a hand or head...

  5. Broadband Ground Penetrating Radar with conformal antennas for subsurface imaging from a rover

    Science.gov (United States)

    Stillman, D. E.; Oden, C. P.; Grimm, R. E.; Ragusa, M.

    2015-12-01

    Ground-Penetrating Radar (GPR) allows subsurface imaging to provide geologic context and will be flown on the next two martian rovers (WISDOM on ExoMars and RIMFAX on Mars 2020). The motivation of our research is to minimize the engineering challenges of mounting a GPR antenna to a spacecraft, while maximizing the scientific capabilities of the GPR. The scientific capabilities increase with the bandwidth as it controls the resolution. Furthermore, ultra-wide bandwidth surveys allow certain mineralogies and rock units to be discriminated based on their frequency-dependent EM or scattering properties. We have designed and field-tested a prototype GPR that utilizes bi-static circularly polarized spiral antennas. Each antenna has a physical size of 61 x 61 x 4 cm, therefore two antennas could be mounted to the underbelly of a MSL-class rover. Spiral antennas were chosen because they have an inherent broadband response and provide a better low frequency response compared with similarly sized linearly polarized antennas. A horizontal spiral radiator emits energy both upward and downward directions. After the radiator is mounted to a metal surface (i.e. the underside of a rover), a cavity is formed that causes the upward traveling energy to reverberate and cause unwanted interference. This interference is minimized by 1) using a high metallization ratio on the spiral to reduce cavity emissions, and 2) placing absorbing material inside the cavity. The resulting antennas provide high gain (0 to 8 dBi) from 200 to 1000 MHz. The low frequency response can be improved by increasing the antenna thickness (i.e., cavity depth). In an initial field test, the antennas were combined with impulse GPR electronics that had ~140 dB of dynamic range (not including antennas) and a sand/clay interface 7 feet deep was detected. To utilize the full bandwidth the antennas, a gated Frequency Modulated Continuous Waveform system will be developed - similar to RIMFAX. The goal is to reach a

  6. Scalable Notch Antenna System for Multiport Applications

    Directory of Open Access Journals (Sweden)

    Abdurrahim Toktas

    2016-01-01

    Full Text Available A novel and compact scalable antenna system is designed for multiport applications. The basic design is built on a square patch with an electrical size of 0.82λ0×0.82λ0 (at 2.4 GHz on a dielectric substrate. The design consists of four symmetrical and orthogonal triangular notches with circular feeding slots at the corners of the common patch. The 4-port antenna can be simply rearranged to 8-port and 12-port systems. The operating band of the system can be tuned by scaling (S the size of the system while fixing the thickness of the substrate. The antenna system with S: 1/1 in size of 103.5×103.5 mm2 operates at the frequency band of 2.3–3.0 GHz. By scaling the antenna with S: 1/2.3, a system of 45×45 mm2 is achieved, and thus the operating band is tuned to 4.7–6.1 GHz with the same scattering characteristic. A parametric study is also conducted to investigate the effects of changing the notch dimensions. The performance of the antenna is verified in terms of the antenna characteristics as well as diversity and multiplexing parameters. The antenna system can be tuned by scaling so that it is applicable to the multiport WLAN, WIMAX, and LTE devices with port upgradability.

  7. Vital Sign Monitoring Through the Back Using an UWB Impulse Radar With Body Coupled Antennas.

    Science.gov (United States)

    Schires, Elliott; Georgiou, Pantelis; Lande, Tor Sverre

    2018-04-01

    Radar devices can be used in nonintrusive situations to monitor vital sign, through clothes or behind walls. By detecting and extracting body motion linked to physiological activity, accurate simultaneous estimations of both heart rate (HR) and respiration rate (RR) is possible. However, most research to date has focused on front monitoring of superficial motion of the chest. In this paper, body penetration of electromagnetic (EM) wave is investigated to perform back monitoring of human subjects. Using body-coupled antennas and an ultra-wideband (UWB) pulsed radar, in-body monitoring of lungs and heart motion was achieved. An optimised location of measurement in the back of a subject is presented, to enhance signal-to-noise ratio and limit attenuation of reflected radar signals. Phase-based detection techniques are then investigated for back measurements of vital sign, in conjunction with frequency estimation methods that reduce the impact of parasite signals. Finally, an algorithm combining these techniques is presented to allow robust and real-time estimation of both HR and RR. Static and dynamic tests were conducted, and demonstrated the possibility of using this sensor in future health monitoring systems, especially in the form of a smart car seat for driver monitoring.

  8. Miniaturized CPW-Fed Triband Antenna with Asymmetric Ring for WLAN/WiMAX Applications

    Directory of Open Access Journals (Sweden)

    Shanshan Huang

    2014-01-01

    Full Text Available A compact CPW-fed triband slot antenna for WLAN/WiMAX applications is proposed. The proposed antenna is formed by an asymmetric ring, an inverted L-strip, and a straight strip. By employing these structures, the antenna can generate three operation bands with compact size and simple structure. The measured and simulated results show the presented antenna has impedance bandwidths of 100 MHz (2.39–2.49 GHz, 360 MHz (3.36–3.72 GHz, and 760 MHz (5.13–5.89 GHz, which covers both WLAN in the 2.4/5.2 GHz bands and WiMAX in the 3.5/5.5 GHz bands. The antenna is successfully simulated and measured, showing triple bands can be obtained by using three different radiators and also indicating that the proposed antenna is suitable for the WiMAX/WLAN applications.

  9. Graphene-based Yagi-Uda antenna with reconfigurable radiation patterns

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yongle, E-mail: wuyongle138@gmail.com; Qu, Meijun; Jiao, Lingxiao; Liu, Yuanan [School of Electronic Engineering, Beijing Key Laboratory of Work Safety Intelligent Monitoring, Beijing University of Posts and Telecommunications, P. O. Box. 282, Beijing, 100876 (China); Ghassemlooy, Zabih [Optical Communications Research Group, NCRLab, Faculty of Engineering and Environment, Northumbria University, Newcastle upon Tyne, NE1 8ST (United Kingdom)

    2016-06-15

    This paper presents a radiation pattern reconfigurable Yagi-Uda antenna based on graphene operating at terahertz frequencies. The antenna can be reconfigured to change the main beam pattern into two or four different radiation directions. The proposed antenna consists of a driven dipole radiation conductor, parasitic strips and embedded graphene. The hybrid graphene-metal implementation enables the antenna to have dynamic surface conductivity, which can be tuned by changing the chemical potentials. Therefore, the main beam direction, the resonance frequency, and the front-to-back ratio of the proposed antenna can be controlled by tuning the chemical potentials of the graphene embedded in different positions. The proposed two-beam reconfigurable Yagi-Uda antenna can achieve excellent unidirectional symmetrical radiation pattern with the front-to-back ratio of 11.9 dB and the10-dB impedance bandwidth of 15%. The different radiation directivity of the two-beam reconfigurable antenna can be achieved by controlling the chemical potentials of the graphene embedded in the parasitic stubs. The achievable peak gain of the proposed two-beam reconfigurable antenna is about 7.8 dB. Furthermore, we propose a four-beam reconfigurable Yagi-Uda antenna, which has stable reflection-coefficient performance although four main beams in reconfigurable cases point to four totally different directions. The corresponding peak gain, front-to-back ratio, and 10-dB impedance bandwidth of the four-beam reconfigurable antenna are about 6.4 dB, 12 dB, and 10%, respectively. Therefore, this novel design method of reconfigurable antennas is extremely promising for beam-scanning in terahertz and mid-infrared plasmonic devices and systems.

  10. Low-Profile Multiband and Flush-Mountable Wideband Antennas for HF/VHF and K/Ka Band Applications

    Science.gov (United States)

    Garrido Lopez, David

    emissions are planned. Following the same trend of antenna system size reduction with extension of capabilities in a congested spectral environment, the millimeter wave spectrum is explored next. Specifically, antenna systems for wideband amplitude only (AO) direction finding (DF) are thoroughly considered. Theory and design considerations are developed to fill gaps in open literature. Typical sources of errors are theoretically analyzed, and a discussion on limitations and advantages of different AO DF architectures is given. Practical millimeter wave realizations of AO DF antenna front-ends in the K/Ka/Q bands (18-45 GHz) are developed using two different architectures: a passive phased-array and a squinted antenna system. For the former, a tightly coupled two-element tapered slot antenna (TSA) array with a stacked arrangement is developed. A novel enclosure of the array inside an absorbing cavity is proposed and improved system performance with flush mounted configuration is demonstrated. The squinted antenna system avoids the use of a beamformer, therefore reducing insertion loss and amplitude/phase imbalances to reduce DF errors. For design robustness, the same TSA element used in the phased-array configuration is used. A novel tapered cavity is also developed to stabilize H-plane radiation patterns and suppress sidelobes. It is seen that the squinted antenna AO DF front-end has better performance than the phased-array antenna system at the expense of larger size.

  11. A compact 5.5 GHz band-rejected UWB antenna using complementary split ring resonators.

    Science.gov (United States)

    Islam, M M; Faruque, M R I; Islam, M T

    2014-01-01

    A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm(2), and VSWR WLAN band.

  12. Optically Controlled Reconfigurable Antenna Array Based on E-Shaped Elements

    Directory of Open Access Journals (Sweden)

    Arismar Cerqueira Sodré Junior

    2014-01-01

    Full Text Available This work presents the development of optically controlled reconfigurable antenna arrays. They are based on two patch elements with E-shaped slots, a printed probe, and a photoconductive switch made from an intrinsic silicon die. Numerical simulations and experiments have been shown to be in agreement, and both demonstrate that the frequency response of the antenna arrays can be efficiently reconfigured over two different frequency ISM bands, namely, 2.4 and 5 GHz. A measured gain of 12.5 dBi has been obtained through the use of two radiating elements printed in a low-cost substrate and a dihedral corner reflector.

  13. PVD Silicon Carbide as a Thin Film Packaging Technology for Antennas on LCP Substrates for Harsh Environments

    Science.gov (United States)

    Scardelletti, Maximilian C.; Stanton, John W.; Ponchak, George E.; Jordan, Jennifer L.; Zorman, Christian A.

    2010-01-01

    This paper describes an effort to develop a thin film packaging technology for microfabricated planar antennas on polymeric substrates based on silicon carbide (SiC) films deposited by physical vapor deposition (PVD). The antennas are coplanar waveguide fed dual frequency folded slot antennas fabricated on liquid crystal polymer (LCP) substrates. The PVD SiC thin films were deposited directly onto the antennas by RF sputtering at room temperature at a chamber pressure of 30 mTorr and a power level of 300 W. The SiC film thickness is 450 nm. The return loss and radiation patterns were measured before and after the SiC-coated antennas were submerged into perchloric acid for 1 hour. No degradation in RF performance or physical integrity of the antenna was observed.

  14. Plasma antennas: dynamically configurable antennas for communications

    International Nuclear Information System (INIS)

    Borg, G.; Harris, J.

    1999-01-01

    In recent years, the rapid growth in both communications and radar systems has led to a concomitant growth in the possible applications and requirements of antennas. These new requirements include compactness and conformality, rapid reconfigurability for directionality and frequency agility. For military applications, antennas should also allow low absolute or out-of-band radar cross-section and facilitate low probability of intercept communications. Investigations have recently begun worldwide on the use of ionised gases or plasmas as the conducting medium in antennas that could satisfy these requirements. Such plasma antennas may even offer a viable alternative to metal in existing applications when overall technical requirements are considered. A recent patent for ground penetrating radar claims the invention of a plasma antenna for the transmission of pulses shorter than 100 ns in which it is claimed that current ringing is avoided and signal processing simplified compared with a metal antenna. A recent US ONR tender has been issued for the design and construction of a compact and rapidly reconfigurable antenna for dynamic signal reception over the frequency range 1 - 45 GHz based on plasma antennas. Recent basic physics experiments at ANU have demonstrated that plasma antennas can attain adequate efficiency, predictable radiation patterns and low base-band noise for HF and VHF communications. In this paper we describe the theory of the low frequency plasma antenna and present a few experimental results

  15. Information guided channel hopping with an arbitrary number of transmit antennas

    KAUST Repository

    Yang, Yuli; Aï ssa, Sonia

    2012-01-01

    In order to realize the information guided channel hopping, also known as spatial modulation, with more design flexibility, in this paper we propose a novel scheme that allows operation with an arbitrary number of transmit antennas. Once the number of transmit antennas is not a power of two, the antennas' symbols are mapped by different numbers of bits. Subsequently, constellations with different orders are exploited for the modulation of radiated symbols so as to guarantee that the total number of bits transmitted at each time slot remains the same. Furthermore, we introduce a decoding algorithm with low complexity for this design. Numerical results on bit error rate performance are provided and substantiate that the proposed scheme turns out to be a promising alternative to the design of information guided channel hopping. © 2012 IEEE.

  16. Information guided channel hopping with an arbitrary number of transmit antennas

    KAUST Repository

    Yang, Yuli

    2012-10-01

    In order to realize the information guided channel hopping, also known as spatial modulation, with more design flexibility, in this paper we propose a novel scheme that allows operation with an arbitrary number of transmit antennas. Once the number of transmit antennas is not a power of two, the antennas\\' symbols are mapped by different numbers of bits. Subsequently, constellations with different orders are exploited for the modulation of radiated symbols so as to guarantee that the total number of bits transmitted at each time slot remains the same. Furthermore, we introduce a decoding algorithm with low complexity for this design. Numerical results on bit error rate performance are provided and substantiate that the proposed scheme turns out to be a promising alternative to the design of information guided channel hopping. © 2012 IEEE.

  17. Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application

    Science.gov (United States)

    Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

    2016-01-01

    Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software—High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication. PMID:27355954

  18. Design and fabrication of a microstrip patch antenna with a low radar cross section in the X-band

    International Nuclear Information System (INIS)

    Jang, Hong-Kyu; Lee, Won-Jun; Kim, Chun-Gon

    2011-01-01

    In this study, the authors developed a radar absorbing method to reduce the antenna radar cross section (RCS) without any loss of antenna performance. The new method was based upon an electromagnetic bandgap (EBG) absorber using conducting polymer (CP). First, a microstrip patch antenna was made by using a copper film and glass/epoxy composite materials, which are typically used for load-bearing structures, such as aircraft and other vehicles. Then, CP EBG patterns were also designed that had a 90% electromagnetic (EM) wave absorbing performance within the X-band (8.2–12.4 GHz). Finally, the CP EBG patterns were printed on the top surface of the microstrip patch antenna. The measured radar absorbing performance of the fabricated patch antenna showed that the frontal RCS of the antenna declined by nearly 95% at 10 GHz frequency while the CP EBG patterns had almost no effect on the antenna's performance

  19. Organized Oscillations of Initially-Turbulent Flow Past a Cavity

    Energy Technology Data Exchange (ETDEWEB)

    J.C. Lin; D. Rockwell

    2002-09-17

    Flow past an open cavity is known to give rise to self-sustained oscillations in a wide variety of configurations, including slotted-wall, wind and water tunnels, slotted flumes, bellows-type pipe geometries, high-head gates and gate slots, aircraft components and internal piping systems. These cavity-type oscillations are the origin of coherent and broadband sources of noise and, if the structure is sufficiently flexible, flow-induced vibration as well. Moreover, depending upon the state of the cavity oscillation, substantial alterations of the mean drag may be induced. In the following, the state of knowledge of flow past cavities, based primarily on laminar inflow conditions, is described within a framework based on the flow physics. Then, the major unresolved issues for this class of flows will be delineated. Self-excited cavity oscillations have generic features, which are assessed in detail in the reviews of Rockwell and Naudascher, Rockwell, Howe and Rockwell. These features, which are illustrated in the schematic of Figure 1, are: (i) interaction of a vorticity concentration(s) with the downstream corner, (ii) upstream influence from this corner interaction to the sensitive region of the shear layer formed from the upstream corner of the cavity; (iii) conversion of the upstream influence arriving at this location to a fluctuation in the separating shear layer; and (iv) amplification of this fluctuation in the shear layer as it develops in the streamwise direction. In view of the fact that inflow shear-layer in the present investigation is fully turbulent, item (iv) is of particular interest. It is generally recognized, at least for laminar conditions at separation from the leading-corner of the cavity, that the disturbance growth in the shear layer can be described using concepts of linearized, inviscid stability theory, as shown by Rockwell, Sarohia, and Knisely and Rockwell. As demonstrated by Knisely and Rockwell, on the basis of experiments interpreted

  20. A novel very wideband integrated antenna system for 4G and 5G mm-wave applications

    KAUST Repository

    Ikram, M.

    2017-09-22

    In this work, a novel very wideband 4-element monopole based multiple-input multiple-output (MIMO) antenna system with single connected antenna array (CAA) is presented. The CAA is based on a single slot which is etched on the ground plane. A 2 × 1 power divider/combiner is used to excite the slot to act as a CAA. The proposed design covers the 4G bands between 1850 and 3700, and the 28 GHz 5G band. The covered bandwidths are 1462 and 240 MHz from 1843 to 3305 MHz and 3500 to 3740 MHz, respectively, for 4G applications. A bandwidth of 1.22 GHz from 27.5 to 28.72 GHz is obtained for 5G applications. The proposed antenna system is designed on a double layer RO4350B substrate with height of 0.76 mm and dielectric constant of 3.5. The total size of the design is 115 × 65 × 0.76 mm. It is compact, low profile and suitable for wireless handheld devices. The MIMO performance metrics such as isolation and ECC are evaluated and good agreement between simulations and measurements is achieved.

  1. A Compact CPW-Fed UWB Antenna with Dual Band-Notched Characteristics

    Directory of Open Access Journals (Sweden)

    Aiting Wu

    2013-01-01

    Full Text Available A compact CPW-fed planar UWB antenna with dual band-notched property is presented. The dual band rejection is achieved by etching a C-shaped slot on the radiation patch and two L-shaped parasitic strips in the ground plane. The experimental and measured results show that the proposed antenna exhibits an impedance bandwidth over an ultrawideband frequency range from 2.4 to 12.5 GHz with VSWR less than 2, except for two stopbands at 3.3 to 3.75 GHz and 5.07 to 5.83 GHz for filtering the WiMAX and WLAN signals, respectively. It also demonstrates a nearly omnidirectional radiation pattern. The fabricated antenna has a tiny size, only 32 mm × 32 mm × 0.508 mm. The simulated results are compared with the measured performance and show good agreement. The simple structure, compact size, and good characteristics make the proposed antenna an excellent candidate for UWB applications.

  2. A novel bridge coupler for SSC coupled cavity linac

    International Nuclear Information System (INIS)

    Yao, C.G.; Chang, C.R.; Funk, W.

    1992-01-01

    A novel magnetically coupled multi-cavity bridge coupler is proposed for SSC Coupled-Cavity-Linac (CCL). The bridge coupler is a five cell disc-loaded waveguide with a small central aperture used for measurement and two large curved coupling slots near the edge on each disc. The two coupling slots on the adjacent disc are rotated 90 degrees in orientation to reduce the direct coupling. This type of structure is capable of producing very large coupling (>10% in our longest bridge coupler). Also because of the small opening on the discs, the high-order-modes are very far (> 300 MHz) above the operating mode. Thus for long bridge couplers, the magnetic coupled structure should provide maximum coupling with minimum mode mixing problems. In this paper both physics and engineering issues of this new bridge coupler are presented. (Author) 5 refs., 2 tabs., 6 figs

  3. Substrate Integrated Waveguide Cross-Coupling Filter with Multilayer Hexagonal Cavity

    Directory of Open Access Journals (Sweden)

    B. Wu

    2013-01-01

    Full Text Available Hexagonal cavities and their applications to multilayer substrate integrated waveguide (SIW filters are presented. The hexagonal SIW cavity which can combine flexibility of rectangular one and performance of circular one is convenient for bandpass filter’s design. Three types of experimental configuration with the same central frequency of 10 GHz and bandwidth of 6%, including three-order and four-order cross-coupling topologies, are constructed and fabricated based on low temperature cofired ceramic (LTCC technology. Both theoretical and experimental results are presented.

  4. 8×8 Planar Phased Array Antenna with High Efficiency and Insensitivity Properties for 5G Mobile Base Stations

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2016-01-01

    An insensitive planar phased array antenna with high efficiency function for 5G applications is introduced in this study. 64-elements of compact slot-loop antenna elements have been used to form the 8×8 planar array. The antenna is designed on a low cost FR4 substrate and has good performance in ...... at both sides of the substrate and could be used for mobile base station (MBS) applications. The proposed planar array could be integrated with the transceivers on the low-cost printed circuit boards (PCBs) to reduce the manufacturing cost....

  5. Slotted Antenna with Anisotropic Magnetic Loading

    Science.gov (United States)

    2016-07-26

    May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...therefor. CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention

  6. A Dual-Band Multiple Input Multiple Output Frequency Agile Antenna for GPSL1/Wi-Fi/WLAN2400/LTE Applications

    Directory of Open Access Journals (Sweden)

    Sajid Aqeel

    2016-01-01

    Full Text Available A novel dual-band, single element multiple input multiple output (MIMO dielectric resonator antenna (DRA with a modest frequency tuning ability is presented in this communication. The proposed antenna operates at GPS L1/Bluetooth/Wi-Fi/LTE2500/WLAN2400 frequency bands. A single dielectric resonator element is fed by two coaxial probes to excite the orthogonal modes. A couple of slots are introduced on the ground plane to improve the isolation between antenna ports. The slots also serve the purpose of reconfiguration in the lower band on placement of switches at optimized locations. The measured impedance bandwidth is 5.16% (1.41–1.49 GHz in the lower band and 26% (2.2–2.85 GHz in the higher band. The lower band reconfigures with an impedance bandwidth of 6.5% (1.55–1.65 GHz when PIN diodes are switched ON. The gain, efficiency, correlation coefficient, and diversity gain of the MIMO DRA are presented with a close agreement between simulated and measured results.

  7. Studies on diversion cross-flow between two parallel channels communicating by a lateral slot. II

    International Nuclear Information System (INIS)

    Tapucu, A.; Merilo, M.

    1977-01-01

    The axial pressure variations of two parallel channels with single phase flows communicating by a long lateral slot have been studied experimentally. Using mass and momentum conservation principles, the axial pressure variations have been derived in terms of two parameters ksub(d) and ksub(r), for donor and recipient channels, respectively. These parameters include the combined effect of fluid transferred from donor to recipient channel, and drag force brought on by the connection gap, and are functions of the velocities and slot geometry parameters. A pressure difference oscillation between channels along the slot has been detected which is sinusoidal with wave lengths which seem to be a function of the gap clearance. (Auth.)

  8. Development of a Semielliptical Partial Ground Plane Antenna for RFID and GSM-900

    Directory of Open Access Journals (Sweden)

    M. R. Zaman

    2014-01-01

    Full Text Available A novel compact broadband patch antenna for UHF (ultrahigh frequency, RFID (radio frequency identification, and GSM-900 (global system for mobile communications band is shown in this paper. The antenna is composed of an ellipse shape annular ring at the patch. The ground plane of the planar antenna is modified with a semiellipse shape slot. The structure can generate substantial amount of current at the feed-line. The geometry of the antenna is evaluated by using HFSS simulation software and deliberated across the paper. Parametric study is exhibited to delineate the response change of the antenna. The antenna has a physical width of 0.24 λ and length of 0.3 λ. It covers a frequency starting from 0.9 GHz to 1.08 GHz. A fractional bandwidth of 18.2% has been achieved from 0.9 GHz till 1.08 GHz. An average gain of 5.5 dBi is achieved at the resonance frequency. The simulated and measured results have good agreement.

  9. Engineered SOI slot waveguide ring resonator V-shape resonance combs for refraction index sensing up to 1300nm/RIU (Conference Presentation)

    Science.gov (United States)

    Zhang, Weiwei; Serna, Samuel; Le Roux, Xavier; Vivien, Laurent; Cassan, Eric

    2016-05-01

    Bio-detection based on CMOS technology boosts the miniaturization of detection systems and the success on highly efficient, robust, accurate, and low coast Lab-on-Chip detection schemes. Such on chip detection technologies have covered healthy related harmful gases, bio-chemical analytes, genetic micro RNA, etc. Their monitoring accuracy is mainly qualified in terms of sensitivity and limit of the detection (LOD) of the detection system. In this context, recently developed silicon on insulator (SOI) optical devices have displayed highly performant detection abilities that LOD could go beyond 10-8RIU and sensitivity could exceeds 103nm/RIU. The SOI integrated optical sensing devices include strip/slotted waveguide consisting in structures like Mach-Zehnder interferometers (MZI), ring resonators (RR), nano cavities, etc. Typically, hollow core RR and nano-cavities could exhibit higher sensitivity due to their optical mode confinement properties with a partial localization of the electric field in low index sensing regions than devices based on evanescent field tails outside of the optical cores. Furthermore, they also provide larger sensing areas for surface functionalization to reach higher sensitivities and lower LODs. The state of art of hollow core devices, either based on Bragg gratings formed from a slot waveguide cavity or photonic crystal slot cavities, show sensitivities (S) up to 400nm/RIU and Figure of Merit (FOM) around 3,000 in water environment, FOM being defined as the inverse of LOD and precisely as FOM=SQ/λ, with λ the resonance wavelength and Q the quality factor of the considered resonator. Such high achieved FOMs in nano cavities are mainly due to their large Q factors around 15,000. While for mostly used RR, which do not require particular design strategies, relatively low Q factors around 1800 in water are met and moderate sensitivities about 300nm/RIU are found. In this work, we present here a novel slot ring resonator design to make

  10. Reducing mechanical cross-coupling in phased array transducers using stop band material as backing

    Science.gov (United States)

    Henneberg, J.; Gerlach, A.; Storck, H.; Cebulla, H.; Marburg, S.

    2018-06-01

    Phased array transducers are widely used for acoustic imaging and surround sensing applications. A major design challenge is the achievement of low mechanical cross-coupling between the single transducer elements. Cross-coupling induces a loss of imaging resolution. In this work, the mechanical cross-coupling between acoustic transducers is investigated for a generic model. The model contains a common backing with two bending elements bonded on top. The dimensions of the backing are small; thus, wave reflections on the backing edges have to be considered. This is different to other researches. The operating frequency in the generic model is set to a low kHz range. Low operating frequencies are typical for surround sensing applications. The influence of the backing on cross-coupling is investigated numerically. In order to reduce mechanical cross-coupling a stop band material is designed. It is shown numerically that a reduction in mechanical cross-coupling can be achieved by using stop band material as backing. The effect is validated with experimental testing.

  11. 3-D analysis on arbitrarily-shaped ICRF antennas and Faraday shields

    International Nuclear Information System (INIS)

    Chen, G.L.; Whealton, J.H.; Baity, F.W.; Hoffman, D.J.; Owens, T.L.

    1986-01-01

    Cavity antennas with Faraday shields are proposed to couple ion cyclotron radio frequency power for heating fusion plasmas. This application requires small, high-power, low-frequency antennas. The results are presented of a theoretical study of the ICRF antennas being developed for this purpose at the Radio Frequency Test Facility (RFTF). The objectives of this work are to optimize experimental designs and to confirm test results

  12. Optical Nano-antennae as Compact and Efficient Couplers from Free-space to Waveguide Modes

    DEFF Research Database (Denmark)

    Zenin, Vladimir A.; Malureanu, Radu; Volkov, Valentyn

    2015-01-01

    Optical nano-antennae are one of the possible solutions for coupling free-space radiation into subwavelength waveguides. Our efforts were concentrated on coupling between an optical fibre and a plasmonic slot waveguide. Such coupling is still an issue to be solved in order to advance the use...... of plasmonic waveguides for optical interconnects. During the talk, we will present our modelling optimisation, fabrication and measurement of the nano-antennae functionality. For the modelling part, we used CST Microwave studio for optimising the antenna geometry. Various antennae were modelled and fabricated....... The fabrication was based on electron beam lithography and lift-off processes. The measurements were performed with scattering scanning near-field microscope and allowed the retrieval of both amplitude and phase of the propagating plasmon. The obtained values agree very well with the theoretically predicted ones...

  13. A Flexible Monopole Antenna with Dual-Notched Band Function for Ultrawideband Applications

    Directory of Open Access Journals (Sweden)

    Xiaoyan Zhang

    2014-01-01

    Full Text Available We present a flexible ultrawideband (UWB planar monopole antenna with dual-notched band characteristic printed on a polyimide substrate. The antenna is fed by a step coplanar waveguide (CPW that provides smooth transitional impedance for improved matching. It operates from 2.76 to 10.6 GHz with return loss greater than 10 dB except for the notch band to reduce the interference with existing 3.5 GHz WiMAX band and 5.5 GHz WLAN band. With a combination of rectangular and circle patches in which the U-shaped slot is carved, the overall size of antenna is 30 mm × 20 mm. Moreover, a pair of arc-shaped stubs located at both sides of the feed line is utilized to create the notch band for WiMAX band. The results also show that the antenna has omnidirectional radiation pattern and smooth gain over the entire operational band.

  14. Design and development of a unit element microstrip antenna for aircraft collision avoidance system

    Science.gov (United States)

    De, Debajit; Sahu, Prasanna Kumar

    2017-10-01

    Aircraft/traffic alert and collision avoidance system (ACAS/TCAS) is an airborne system which is designed to provide the service as a last defense equipment for avoiding mid-air collisions between the aircraft. In the existing system, four monopole stub-elements are used as ACAS directional antenna and one blade type element is used as ACAS omnidirectional antenna. The existing ACAS antenna has some drawbacks such as low gain, large beamwidth, frequency and beam tuning/scanning issues etc. Antenna issues like unwanted signals reception may create difficulties to identify the possible threats. In this paper, the focus is on the design and development of a unit element microstrip antenna which can be used for ACAS application and to overcome the possible limitations associated with the existing techniques. Two proposed antenna models are presented here, which are single feed and dual feed microstrip dual patch slotted antenna. These are designed and simulated in CST Microwave Studio tool. The performance and other antenna characteristics have been explored from the simulation results followed by the antenna fabrication and measurement. A good reflection coefficient, Voltage Standing Wave Ratio (VSWR), narrow beamwidth, perfect directional radiation pattern, high gain and directivity make this proposed antenna a good candidate for this application.

  15. Ferrite LTCC based phased array antennas

    KAUST Repository

    Ghaffar, Farhan A.

    2016-11-02

    Two phased array antennas realized in multilayer ferrite LTCC technology are presented in this paper. The use of embedded bias windings in these designs allows the negation of external magnets which are conventionally employed with bulk ferrite medium. This reduces the required magnetostatic field strength by 90% as compared to the traditional designs. The phase shifters are implemented using the SIW technology. One of the designs is operated in the half mode waveguide topology while the other design is based on standard full mode waveguide operation. The two phase shifter designs are integrated with two element patch antenna array and slotted SIW array respectively. The array designs demonstrate a beam steering of 30° and ±19° respectively for a current excitation of 200 mA. The designs, due to their small factor can be easily integrated in modern communication systems which is not possible in the case of bulk ferrite based designs.

  16. Cascaded-cavity Fabry-Perot interferometer for simultaneous measurement of temperature and strain with cross-sensitivity compensation

    Science.gov (United States)

    Tian, Jiajun; Jiao, Yuzhu; Ji, Shaobo; Dong, Xiaolong; Yao, Yong

    2018-04-01

    We propose and demonstrate a fiber sensor for simultaneous temperature and strain measurements. The proposed sensor is implemented by a cascaded-cavity Fabry-Perot (FP) fiber interferometer. The two cascaded FP cavities comprise a micro-air-cavity in a hollow-core tube fiber and a micro-silica-cavity in a standard single-mode fiber. To separate the interference spectrum of each FP cavity, the total spectrum is filtered in the frequency domain through band-pass filters, whose central frequencies were predesigned based on the relationship between the spatial frequency and free spectral range of each FP cavity. The different cross-sectional areas and thermal-optic coefficients of the two FP cavities confer different sensitivities to temperature and strain. Both parameters were measured simultaneously by tracking the wavelength shifts in the filtered interference spectra of the FP cavities. Moreover, the temperature-strain cross-sensitivity was compensated by solving a sensitivity-coefficient matrix equation for the two cavities, using the calibrated temperatures and strains. Other advantages of the proposed sensor are simple fabrication and an all-fiber structure. Owing to these properties, the proposed sensor is potentially applicable to real sensing applications.

  17. Design and Analysis of Ultra-wideband Micro Strip Patch Antenna with Notch Band Characteristics

    Directory of Open Access Journals (Sweden)

    Kumar Omprakash

    2016-01-01

    Full Text Available A new design of ultra-wideband (UWB micro strip patch antenna with notch band characteristic for wireless local area network (WLAN application is presented in this paper. The proposed antenna consists of a rectangular patch with a partial ground plane that is fed by 50 Ω micro strip line. A notch band function is created by inserting overlapped one U-shape and one C-shape slot on the radiator patch, added additional patch to the ground plane side and slit in truncated ground plane. The proposed antenna potentially minimized frequency interference between WLAN and UWB system. This antenna with the size of 26 mm × 32 mm (W×L and the simulated results show that the antenna can operate over the frequency band between 3.1 and 10.45 GHz for voltage standing wave ratio (VSWR > 2 with band notch 5.06-5.825 GHz. Besides in the working band, the antenna shows good radiation pattern in the H-plane and the E-plane and has good time domain characteristic.

  18. A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

    Directory of Open Access Journals (Sweden)

    M. M. Islam

    2014-01-01

    Full Text Available A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm2, and VSWR < 2, observing band elimination of 5.5 GHz WLAN band.

  19. Slotted Antenna with Uniaxial Dielectric Covering

    Science.gov (United States)

    2016-07-08

    February 2017 The below identified patent application is available for licensing. Requests for information should be addressed to...therefor. CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present...have been proposed in submarine applications before. For example, in U.S. Patent No. 6,127,983, Rivera and Josypenko disclose a horizontally mounted

  20. An active antenna for ELF magnetic fields

    Science.gov (United States)

    Sutton, John F.; Spaniol, Craig

    1994-01-01

    The work of Nikola Tesla, especially that directed toward world-wide electrical energy distribution via excitation of the earth-ionosphere cavity resonances, has stimulated interest in the study of these resonances. Not only are they important for their potential use in the transmission of intelligence and electrical power, they are important because they are an integral part of our natural environment. This paper describes the design of a sensitive, untuned, low noise active antenna which is uniquely suited to modern earth-ionosphere cavity resonance measurements employing fast-Fourier transform techniques for near-real-time data analysis. It capitalizes on a little known field-antenna interaction mechanism. Recently, the authors made preliminary measurements of the magnetic fields in the earth-ionosphere cavity. During the course of this study, the problem of designing an optimized ELF magnetic field sensor presented itself. The sensor would have to be small, light weight (for portable use), and capable of detecting the 5-50 Hz picoTesla-level signals generated by the natural excitations of the earth-ionosphere cavity resonances. A review of the literature revealed that past researchers had employed very large search coils, both tuned and untuned. Hill and Bostick, for example, used coils of 30,000 turns wound on high permeability cores of 1.83 m length, weighing 40 kg. Tuned coils are unsuitable for modern fast-Fourier transform data analysis techniques which require a broad spectrum input. 'Untuned' coils connected to high input impedance voltage amplifiers exhibit resonant responses at the resonant frequency determined by the coil inductance and the coil distributed winding capacitance. Also, considered as antennas, they have effective areas equal only to their geometrical areas.

  1. Bistatic High Frequency Radar Ocean Surface Cross Section for an FMCW Source with an Antenna on a Floating Platform

    Directory of Open Access Journals (Sweden)

    Yue Ma

    2016-01-01

    Full Text Available The first- and second-order bistatic high frequency radar cross sections of the ocean surface with an antenna on a floating platform are derived for a frequency-modulated continuous wave (FMCW source. Based on previous work, the derivation begins with the general bistatic electric field in the frequency domain for the case of a floating antenna. Demodulation and range transformation are used to obtain the range information, distinguishing the process from that used for a pulsed radar. After Fourier-transforming the autocorrelation and comparing the result with the radar range equation, the radar cross sections are derived. The new first- and second-order antenna-motion-incorporated bistatic radar cross section models for an FMCW source are simulated and compared with those for a pulsed source. Results show that, for the same radar operating parameters, the first-order radar cross section for the FMCW waveform is a little lower than that for a pulsed source. The second-order radar cross section for the FMCW waveform reduces to that for the pulsed waveform when the scattering patch limit approaches infinity. The effect of platform motion on the radar cross sections for an FMCW waveform is investigated for a variety of sea states and operating frequencies and, in general, is found to be similar to that for a pulsed waveform.

  2. Differentially Fed Metal Frame Antenna With Common Mode Suppression for Biomedical Smartband Applications

    Science.gov (United States)

    Xu, Li-Jie; Duan, Zhu

    2018-04-01

    This paper proposes a differentially fed metal frame antenna for biomedical smartband applications. It occupies a planar area of 40 × 20 mm, operating at 2.45-GHz industrial, scientific, and medical band. The proposed antenna is composed of an external metal frame and an internal metal box acting as ground for electronics. Through a differential feeding to two copper strips located between the metal frame and the metal box, a rectangular ring slot is excited with common mode suppression capability. The antenna prototype is designed in free space, and then adapted to on-body scenario for both repeater and transmitter cases. Additionally, the proposed differential feeding is modified to the traditional single port, demonstrating the half-size miniaturization technique. Finally, the simulated results are verified by measurement. The proposed antenna's simple structure and satisfactory performance makes it a perfect candidate for future medical smartband applications, monitoring the physiological parameters of humans for health-care purposes.

  3. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  4. Circularly Polarized Microwave Antenna Element with Very Low Off-Axis Cross-Polarization

    Science.gov (United States)

    Greem. David; DuToit, Cornelis

    2013-01-01

    The goal of this work was to improve off-axis cross-polarization performance and ease of assembly of a circularly polarized microwave antenna element. To ease assembly, the initial design requirement of Hexweb support for the internal circuit part, as well as the radiating disks, was eliminated. There is a need for different plating techniques to improve soldering. It was also desirable to change the design to eliminate soldering as well as the need to use the Hexweb support. Thus, a technique was developed to build the feed without using solder, solving the lathing and soldering issue. Internal parts were strengthened by adding curvature to eliminate Hexweb support, and in the process, the new geometries of the internal parts opened the way for improving the off-axis cross-polarization performance as well. The radiating disks curvatures were increased for increased strength, but it was found that this also improved crosspolarization. Optimization of the curvatures leads to very low off-axis cross-polarization. The feed circuit was curved into a cylinder for improved strength, eliminating Hexweb support. An aperture coupling feed mechanism eliminated the need for feed pins to the disks, which would have required soldering. The aperture coupling technique also improves cross-polarization performance by effectively exciting the radiating disks very close to the antenna s central axis of symmetry. Because of the shape of the parts, it allowed for an all-aluminum design bolted together and assembled with no solder needed. The advantage of a solderless design is that the reliability is higher, with no single-point failure (solder), and no need for special plating techniques in order to solder the unit together. The shapes (curved or round) make for a more robust build without extra support materials, as well as improved offaxis cross-polarization.

  5. Nanometers to centimeters: novel optical nano-antennas, with an eye to scaled production

    Science.gov (United States)

    James, Timothy D.; Cadusch, Jasper J.; Earl, Stuart K.; Panchenko, Evgeniy; Mulvaney, Paul; Davis, Timothy J.; Roberts, Ann

    2016-03-01

    Optical nano-antennas have been the focus of intense research recently due to their ability to manipulate electromagnetic radiation on a subwavelength scale, and there is major interest in such devices for a wide variety of applications in photonics, sensing, and imaging. Significant effort has been put into developing highly compact, novel, next-generation light sources, which have great potential in realizing efficient sub-wavelength single photon sources and enhanced biological and chemical sensors. We have developed a number of innovative optical antenna designs including elements of chiral metasurfaces for enabling circularly polarized emission from quantum sources, new designs derived from Radio Frequency (RF) elements for quantum source enhancement and directionality, and nanostructures for investigating plasmonic dark-modes that have the ability to significantly reduce the Q-factor of nano-antennas. A challenge, however, remains the development of a scalable nanofabrication technology. The capacity to mass-produce nano-antennas will have a considerable impact on the commercial viability of these devices, and greatly improve research throughput. Here we present recent progress in the development of scalable fabrication strategies for producing of nano-antennas and antenna arrays, along with slot based plasmonic optical devices.

  6. Bandwidth enhancement of a dual band planar monopole antenna using meandered microstrip feeding.

    Science.gov (United States)

    Ahsan, M R; Islam, M T; Habib Ullah, M; Misran, N

    2014-01-01

    A meandered-microstrip fed circular shaped monopole antenna loaded with vertical slots on a high dielectric material substrate (ε r = 15) is proposed in this paper. The performance criteria of the proposed antenna have been experimentally verified by fabricating a printed prototype. The experimental results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing meandered-microstrip feeding in assistant of partial ground plane. It is observed that, the -10 dB impedance bandwidth of the proposed antenna at lower band is 44.4% (600 MHz-1 GHz) and at upper band is 28% (2.25 GHz-2.95 GHz). The measured maximum gains of -1.18 dBi and 4.87 dBi with maximum radiation efficiencies have been observed at lower band and upper band, respectively. The antenna configuration and parametric study have been carried out with the help of commercially available computer-aided EM simulator, and a good accordance is perceived in between the simulated and measured results. The analysis of performance criteria and almost consistent radiation pattern make the proposed antenna a suitable candidate for UHF RFID, WiMAX, and WLAN applications.

  7. WHEELSET AXLE WITH THE CAVITY OF UNIFORM CROSS SECTION

    Directory of Open Access Journals (Sweden)

    S. R. Kolesnykov

    2014-10-01

    Full Text Available Purpose. Due to operation in complex loading conditions, the rolling stock wheelsets should provide high reliability, since the train traffic safety largely depends on them. Design and technical condition of wheelsets affect the smoothness, intensity of forces generated by the interaction between the car and track, and the motion resistance. Specificity of the axle operation consists in the fact that it undergoes the bending stresses under loading. These stresses are unevenly distributed along the cross-sectional area, reaching the highest values in the outer fibers and the minimal values in the internal ones. This aspect sets the problem of replacement of the uniform cross section with the hollow cross section. The disadvantages of hollow axle design, which are used at the present time, should include a significant manufacturing complexity of the variable section cavity. The purpose is to develop a modernized design of the wheelset axle. Methodology. A construction of the hollow axle having an inner longitudinal cylindrical through hole of the constant diameter throughout its length was proposed. The item is made of steel seamless tube. The inner surface of the tube is treated by mechanical means to remove the voltage concentrations in the internal longitudinal cylindrical through hole, which has a constant diameter along the entire length of the axle. Findings. Application of this design will facilitate manufacturing of the hollow axle and the machining of the inner longitudinal through hole, while retaining all the use advantages of the hollow axle in the rolling stock wheel pairs. Another use advantage of the hollow axle of this design is the absence of partial heterogeneity of the metal, which is inevitably, occurs during the solid axles blanking. Originality. A new design of the wheelset hollow axle of railway rolling stock was proposed. Practical value. Introduction of the new design simplifying the manufacture and mechanical treatment of

  8. Early 500 MHz prototype LEP RF Cavity with superposed storage cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    The principle of transferring the RF power back and forth between the accelerating cavity and a side-coupled storage cavity was demonstrated with this 500 MHz prototype. In LEP, the accelerating frequency was 352.2 MHz, and accelerating and storage cavities were consequently larger. See also 8002294, 8006061, 8407619X, and Annual Reports 1980, p.115; 1981, p.95; 1985, vol.I, p.13.

  9. Natural cavity characteristics and cavity bird abundance on West Virginia forested islands of the Ohio River

    Science.gov (United States)

    James T. Anderson; Karen A. Riesz

    2013-01-01

    Wildlife habitats connected with forested islands and their back channels (areas where commercial traffic is prohibited) on the Ohio River are valuable to diverse species. However, quantitative data on the importance of these areas to cavity-nesting birds are lacking. We compared cavity-nesting bird use and habitat between back and navigational channel sides of islands...

  10. A Minimized MIMO-UWB Antenna with High Isolation and Triple Band-Notched Functions

    Science.gov (United States)

    Kong, Yuanyuan; Li, Yingsong; Yu, Kai

    2016-11-01

    A compact high isolation MIMO-UWB antenna with triple frequency rejection bands is proposed for UWB communication applications. The proposed MIMO-UWB antenna consists of two identical UWB antennas and each antenna element has a semicircle ring shaped radiation patch fed by a bend microstrip feeding line for covering the UWB band, which operates from 2.85 GHz to 11.79 GHz with an impedance bandwidth of 122.1 %. By etching a L-shaped slot on the ground plane, and embedding an "anchor" shaped stub into the patch and integrating an open ring under the semicircle shaped radiation patch, three notch bands are realized to suppress WiMAX (3.3-3.6 GHz), WLAN(5.725-5.825 GHz) and uplink of X-band satellite (7.9-8.4 GHz) signals. The high isolation with S21<-20 dB in most UWB band is obtained by adding a protruded decoupling structure. The design procedure of the MIMO-UWB antenna is given in detail. The proposed MIMO-UWB antenna is simulated, fabricated and measured. Experimental results demonstrate that the proposed MIMO-UWB antenna has a stable gain, good impedance match, high isolation, low envelope correlation coefficient and good radiation pattern at the UWB operating band and it can provide three designated notch bands.

  11. Dual Wideband Antenna for WLAN/WiMAX and Satellite System Applications Based on a Metamaterial Transmission Line

    International Nuclear Information System (INIS)

    Jin Da-Lin; Hong Jing-Song; Xiong Han

    2012-01-01

    A dual band planar antenna based on metamaterial transmission lines is presented for WLAN, WiMAX, and satellite system communication applications. This antenna is composed of an interdigital capacitor and a ground plane with triangular shaped slots on its top edges to broaden the impedance bandwidth. The measured bandwidth for 10 dB return loss is from 3.29 to 4.27 GHz and 5.04 to 9.8 GHz, covering the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX bands, and the X-band satellite communication systems at 7.4 GHz. The proposed antenna exhibits stable monopole-like radiation patterns and enough gains across the dual operating bands

  12. PIV study of large-scale flow organisation in slot jets

    International Nuclear Information System (INIS)

    Shestakov, Maxim V.; Dulin, Vladimir M.; Tokarev, Mikhail P.; Sikovsky, Dmitrii Ph.; Markovich, Dmitriy M.

    2015-01-01

    Highlights: • Volumetric velocity measurements are perfumed by PIV to analyse 3D flow organisation in a slot jet. • Proper orthogonal decomposition is used to extract coherent flow motion. • Movement of quasi-two-dimensional large-scale vortices is associated with jet meandering. • Amplitude of jet meandering is found to be aperiodically modulated. • Secondary longitudinal vortex rolls are important for cross-stream mixing and momentum transfer. - Abstract: The paper reports on particle image velocimetry (PIV) measurements in turbulent slot jets bounded by two solid walls with the separation distance smaller than the jet width (5–40%). In the far-field such jets are known to manifest features of quasi-two dimensional, two component turbulence. Stereoscopic and tomographic PIV systems were used to analyse local flows. Proper orthogonal decomposition (POD) was applied to extract coherent modes of the velocity fluctuations. The measurements were performed both in the initial region close to the nozzle exit and in the far fields of the developed turbulent slot jets for Re ⩾ 10,000. A POD analysis in the initial region indicates a correlation between quasi-2D vortices rolled-up in the shear layer and local flows in cross-stream planes. While the near-field turbulence shows full 3D features, the wall-normal velocity fluctuations day out gradually due to strong wall-damping resulting in an almost two-component turbulence. On the other hand, the longitudinal vortex rolls take over to act as the main agents in wall-normal and spanwise mixing and momentum transfer. The quantitative analysis indicates that the jet meandering amplitude was aperiodically modulated when arrangement of the large-scale quasi-2D vortices changed between asymmetric and symmetric pattern relatively to the jet axis. The paper shows that the dynamics of turbulent slot jets are more complex than those of 2D, plane and rectangular 3D jets. In particular, the detected secondary longitudinal

  13. Advanced spherical near-field antenna measurement techniques

    DEFF Research Database (Denmark)

    Nielsen, Jeppe Majlund; Pivnenko, Sergey; Breinbjerg, Olav

    2011-01-01

    The DTU-ESA facility has since the 1980es provided highly accurate antenna radiation pattern measurements and gain calibration by use of the probe corrected spherical nearfield technique, both for ESA (the European Space Agency) and other customers and continues to do so. Recent years activities...... and research carried out at the facility are presented in the article. Since 2004 several antenna test facility comparison campaigns were carried out between a number of European antenna measurement facilities. The first campaigns laid the foundation for the later comparisons in providing experience...... in the period 2005–2006 following a series of investigatory measurements and facility updates during 2003–2005. Antenna diagnostics by a SWE-to-PWE transformation presents a case where highly accurate antenna measurements and a plane wave back-projection enable antenna diagnostics by examination...

  14. Numerical investigation of the electric field distribution and the power deposition in the resonant cavity of a microwave electrothermal thruster

    Directory of Open Access Journals (Sweden)

    Mehmet Serhan Yildiz

    2017-04-01

    Full Text Available Microwave electrothermal thruster (MET, an in-space propulsion concept, uses an electromagnetic resonant cavity as a heating chamber. In a MET system, electromagnetic energy is converted to thermal energy via a free floating plasma inside a resonant cavity. To optimize the power deposition inside the cavity, the factors that affect the electric field distribution and the resonance conditions must be accounted for. For MET thrusters, the length of the cavity, the dielectric plate that separates the plasma zone from the antenna, the antenna length and the formation of a free floating plasma have direct effects on the electromagnetic wave transmission and thus the power deposition. MET systems can be tuned by adjusting the lengths of the cavity or the antenna. This study presents the results of a 2-D axis symmetric model for the investigation of the effects of cavity length, antenna length, separation plate thickness, as well as the presence of free floating plasma on the power absorption. Specifically, electric field distribution inside the resonant cavity is calculated for a prototype MET system developed at the Bogazici University Space Technologies Laboratory. Simulations are conducted for a cavity fed with a constant power input of 1 kW at 2.45 GHz using COMSOL Multiphysics commercial software. Calculations are performed for maximum plasma electron densities ranging from 1019 to 1021 #/m3. It is determined that the optimum antenna length changes with changing plasma density. The calculations show that over 95% of the delivered power can be deposited to the plasma when the system is tuned by adjusting the cavity length.

  15. An algorithm for the analysis of inductive antennas of arbitrary cross-section for heating in the ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Lehrman, I.S.; Colestock, P.L.

    1986-10-01

    The application of Ion Cyclotron Range of Frequency (ICRF) heating to near ignited plasmas will require launching structures that will be capable of withstanding the harsh plasma environment. The recessed antenna configuration is expected to provide sufficient protection for the structure, but to date no analysis has been done to determine if adequate coupling can be achieved in such a configuration. In this work we present a method for determining the current distribution for the antenna in the direction transverse to current flow and predict antenna loading in the presence of plasma. Antennas of arbitrary cross section are analyzed above ground planes of arbitrary shape. Results from ANDES, the ANtenna DESign code, are presented and compared to experimental results

  16. PIV and LIF study of slot continuous jet at low Reynolds number

    Directory of Open Access Journals (Sweden)

    Broučková Zuzana

    2016-01-01

    Full Text Available This study deals with a continuous jet issuing from a small narrow slot with a width of 0.36 mm. The experimental arrangement is based on the piezoelectric synthetic jet actuator studied previously for easy comparisons. The working fluid is water at room temperature. The experiments were performed using methods of particle image velocimetry (PIV and flow visualization (laser induced fluorescence, LIF. The time-mean volume flux through the exit nozzle was quantified using precise scales. The mean velocity and the Reynolds number were evaluated as Um = 0.12 m/s and Re = 90, respectively. The results of LIF and PIV techniques revealed the three-dimensional character of the flow field, namely the saddle-shape velocity profiles. This behavior is typical for steady jets from a rectangular nozzle. The obtained results were compared with previous measurements of the synthetic jet issuing from the same cavity and the slot nozzle.

  17. Hybrid method to predict the resonant frequencies and to characterise dual band proximity coupled microstrip antennas

    Science.gov (United States)

    Varma, Ruchi; Ghosh, Jayanta

    2018-06-01

    A new hybrid technique, which is a combination of neural network (NN) and support vector machine, is proposed for designing of different slotted dual band proximity coupled microstrip antennas. Slots on the patch are employed to produce the second resonance along with size reduction. The proposed hybrid model provides flexibility to design the dual band antennas in the frequency range from 1 to 6 GHz. This includes DCS (1.71-1.88 GHz), PCS (1.88-1.99 GHz), UMTS (1.92-2.17 GHz), LTE2300 (2.3-2.4 GHz), Bluetooth (2.4-2.485 GHz), WiMAX (3.3-3.7 GHz), and WLAN (5.15-5.35 GHz, 5.725-5.825 GHz) bands applications. Also, the comparative study of this proposed technique is done with the existing methods like knowledge based NN and support vector machine. The proposed method is found to be more accurate in terms of % error and root mean square % error and the results are in good accord with the measured values.

  18. Electro-optical modulator in a polymerinfiltrated silicon slotted photonic crystal waveguide heterostructure resonator.

    Science.gov (United States)

    Wülbern, Jan Hendrik; Petrov, Alexander; Eich, Manfred

    2009-01-05

    We present a novel concept of a compact, ultra fast electro-optic modulator, based on photonic crystal resonator structures that can be realized in two dimensional photonic crystal slabs of silicon as core material employing a nonlinear optical polymer as infiltration and cladding material. The novel concept is to combine a photonic crystal heterostructure cavity with a slotted defect waveguide. The photonic crystal lattice can be used as a distributed electrode for the application of a modulation signal. An electrical contact is hence provided while the optical wave is kept isolated from the lossy metal electrodes. Thereby, well known disadvantages of segmented electrode designs such as excessive scattering are avoided. The optical field enhancement in the slotted region increases the nonlinear interaction with an external electric field resulting in an envisaged switching voltage of approximately 1 V at modulation speeds up to 100 GHz.

  19. Integrated Lens Antennas for Multi-Pixel Receivers

    Science.gov (United States)

    Lee, Choonsup; Chattopadhyay, Goutam

    2011-01-01

    Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi

  20. Effect of pole number and slot number on performance of dual rotor permanent magnet wind power generator using ferrite magnets

    Directory of Open Access Journals (Sweden)

    Peifeng Xu

    2017-05-01

    Full Text Available Dual rotor permanent magnet (DRPM wind power generator using ferrite magnets has the advantages of low cost, high efficiency, and high torque density. How to further improve the performance and reduce the cost of the machine by proper choice of pole number and slot number is an important problem to be solved when performing preliminarily design a DRPM wind generator. This paper presents a comprehensive performance comparison of a DRPM wind generator using ferrite magnets with different slot and pole number combinations. The main winding factors are calculated by means of the star of slots. Under the same machine volume and ferrite consumption, the flux linkage, back-electromotive force (EMF, cogging torque, output torque, torque pulsation, and losses are investigated and compared using finite element analysis (FEA. The results show that the slot and pole number combinations have an important impact on the generator properties.

  1. ICRF current drive by using antenna phase control

    International Nuclear Information System (INIS)

    Kishimoto, Y.; Itoh, K.

    1987-01-01

    A global analysis of current drive in tokamaks by using waves in the ion cyclotron range of frequencies (ICRF), considering the entire antenna-plasma system, is presented. A phase shifted antenna array is used to inject toroidal momentum into the electrons. Within the context of quasi-linear theory, a Fokker-Planck calculation is combined with an ICRF wave propagation-absorption analysis which includes kinetic effects and realistic boundary conditions. The radial profile of the current induced by the mode converted ion Bernstein wave and by the magnetosonic fast wave is obtained, together with the global current drive efficiency (total induced current/total emitted power from the antennas) in the high density and temperature plasma regime. The phase dependence of the global efficiency is investigated by changing the launching conditions such as the total antenna number and the antenna spacing. In medium size tokamaks, the electron power absorption and the associated driven current are found to be affected considerably by the plasma cavity resonance. It is also found that the global efficiency is sensitive to the antenna spacing. When the antenna spacing is increased, the global efficiency is reduced by counter current generation. (author)

  2. Misalignment sensitivity in an intra-cavity coherently combined crossed-Porro resonator configuration

    Science.gov (United States)

    Alperovich, Z.; Buchinsky, O.; Greenstein, S.; Ishaaya, A. A.

    2017-08-01

    We investigate the misalignment sensitivity in a crossed-Porro resonator configuration when coherently combining two pulsed multimode Nd:YAG laser channels. To the best of our knowledge, this is the first reported study of this configuration. The configuration is based on a passive intra-cavity interferometric combiner that promotes self-phase locking and coherent combining. Detailed misalignment sensitivity measurements are presented, examining both translation and angular deviations of the end prisms and combiner, and are compared to the results for standard flat end-mirror configurations. The results show that the most sensitive parameter in the crossed-Porro resonator configuration is the angular tuning of the intra-cavity interferometric combiner, which is ~±54 µrad. In comparison, with the flat end mirror configuration, the most sensitive parameter in the resonator is the angular tuning of the output coupler, which is ~±11 µrad. Thus, with the crossed-Porro configuration, we obtain significantly reduced sensitivity. This ability to reduce the misalignment sensitivity in coherently combined solid-state configurations may be beneficial in paving their way into practical use in a variety of demanding applications.

  3. Fabrication of Antenna-Coupled KID Array for Cosmic Microwave Background Detection

    Science.gov (United States)

    Tang, Q. Y.; Barry, P. S.; Basu Thakur, R.; Kofman, A.; Nadolski, A.; Vieira, J.; Shirokoff, E.

    2018-05-01

    Kinetic inductance detectors (KIDs) have become an attractive alternative to traditional bolometers in the sub-mm and mm observing community due to their innate frequency multiplexing capabilities and simple lithographic processes. These advantages make KIDs a viable option for the O(500,000) detectors needed for the upcoming Cosmic Microwave Background-Stage 4 experiment. We have fabricated an antenna-coupled MKID array in the 150 GHz band optimized for CMB detection. Our design uses a twin-slot antenna coupled to an inverted microstrip made from a superconducting Nb/Al bilayer as the strip, a Nb ground plane and a SiN_x dielectric layer in between, which is then coupled to an Al KID grown on high-resistivity Si. We present the fabrication process and measurements of SiN_x microstrip resonators.

  4. Regenerative BBU starting currents in standing wave cavities

    International Nuclear Information System (INIS)

    Vetter, A.M.; Buller, T.L.

    1992-01-01

    An analytical method for determining regenerative beam breakup (BBU) starting current, in which the contributions of single-cell field configuration and multi-cell structure mode are separated, is described. The field configuration within each cell is determined to close approximation through the use of mesh codes, which also relate the wall losses to the voltage drop along the beam path. The cell-to-cell amplitude variation may be determined by bead pull measurements on model cavities, or by assuming idealized structure modes. As an example, the I S Q L product for TM 110 -like modes of a 433-MHz, 5-cell, slot-coupled cavity is obtained. (author). 3 figs

  5. Tri-band small monopole antenna based on SRR units

    Directory of Open Access Journals (Sweden)

    Gehan Shehata

    2015-12-01

    Full Text Available In this paper a novel design for a tri-band monopole antenna coupled with metamaterial units is introduced. The proposed antenna was designed to cover WiMAX (2.5, 3.5 and WLAN (5.2 bands. In our proposal, a coplanar waveguide (CPW fed circular-disk monopole antenna is coupled with three split ring resonator (SRR units which exist on its back side. In our design a monopole antenna and SRR units are designed first to resonate at 5.2 GHz and 2.5 GHz respectively. In addition, antenna is loaded with post to force resonance at 3.5 GHz. SRR units are used for 2.5 GHz resonance to miniaturize antenna size, and our proposed antenna considered an electrically small antenna (ESA at its first resonance frequency. Simulated and measured results exhibit a good agreement that validate our design.

  6. A Ferrite LTCC-Based Monolithic SIW Phased Antenna Array

    KAUST Repository

    Nafe, Ahmed A.; Ghaffar, Farhan A.; Farooqui, Muhammad Fahad; Shamim, Atif

    2016-01-01

    In this work, we present a novel configuration for realizing monolithic SIW-based phased antenna arrays using Ferrite LTCC technology. Unlike the current common schemes for realizing SIW phased arrays that rely on surface-mount component (p-i-n diodes, etc) for controlling the phase of the individual antenna elements, here the phase is tuned by biasing of the ferrite filling of the SIW. This approach eliminates the need for mounting of any additional RF components and enables seamless monolithic integration of phase shifters and antennas in SIW technology. As a proof of concept, a two-element slotted SIW-based phased array is designed, fabricated and measured. The prototype exhibits a gain of 4.9 dBi at 13.2 GHz and a maximum E-plane beam-scanning of 28 degrees using external windings for biasing the phase shifters. Moreover, the array can achieve a maximum beam-scanning of 19 degrees when biased with small windings that are embedded in the package. This demonstration marks the first time a fully monolithic SIW-based phased array is realized in Ferrite LTCC technology and paves the way for future larger-size implementations.

  7. A Ferrite LTCC-Based Monolithic SIW Phased Antenna Array

    KAUST Repository

    Nafe, Ahmed

    2016-11-17

    In this work, we present a novel configuration for realizing monolithic SIW-based phased antenna arrays using Ferrite LTCC technology. Unlike the current common schemes for realizing SIW phased arrays that rely on surface-mount component (p-i-n diodes, etc) for controlling the phase of the individual antenna elements, here the phase is tuned by biasing of the ferrite filling of the SIW. This approach eliminates the need for mounting of any additional RF components and enables seamless monolithic integration of phase shifters and antennas in SIW technology. As a proof of concept, a two-element slotted SIW-based phased array is designed, fabricated and measured. The prototype exhibits a gain of 4.9 dBi at 13.2 GHz and a maximum E-plane beam-scanning of 28 degrees using external windings for biasing the phase shifters. Moreover, the array can achieve a maximum beam-scanning of 19 degrees when biased with small windings that are embedded in the package. This demonstration marks the first time a fully monolithic SIW-based phased array is realized in Ferrite LTCC technology and paves the way for future larger-size implementations.

  8. G-Tunnel pressurized slot-testing preparations

    International Nuclear Information System (INIS)

    Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations

  9. Circularly polarized triple band glass shaped monopole patch antenna with metallic reflector for bluetooth & wireless applications

    Science.gov (United States)

    Jangid, K. G.; Choudhary, N.; Jain, P.; Sharma, B. R.; Saini, J. S.; Kulhar, V. S.; Bhatnagar, D.

    2016-03-01

    This paper presents the design and performance of strip line fed glass shaped monopole patch antenna having with overall size 30mm × 30 mm × 1.59 mm. In the patch; an eight shaped slot and in the ground plane an eight shaped ring are introduced. A metallic ground plane is also introduced at appropriate location beneath the ground plane. The proposed antenna is simulated by applying CST Microwave Studio simulator. Antenna provides circularly polarized radiations, triple broad impedance bandwidth of 203MHz (2.306GHz to 2.510GHz), 42MHz (2.685GHz to 2.757GHz) & GHz (3.63 GHz to 6.05 GHz), high flat gain (close to 5dBi) and good radiation properties in the desired frequency range. This antenna may be a very useful tool for 2.45GHz Bluetooth communication band as well as for 2.4GHz/5.2 GHz /5.8 GHz WLAN bands & 3.7GHz/5.5 GHz Wi-Max bands.

  10. Optical Slot-Waveguide Based Biochemical Sensors

    Directory of Open Access Journals (Sweden)

    Carlos Angulo Barrios

    2009-06-01

    Full Text Available Slot-waveguides allow light to be guided and strongly confined inside a nanometer-scale region of low refractive index. Thus stronger light-analyte interaction can be obtained as compared to that achievable by a conventional waveguide, in which the propagating beam is confined to the high-refractive-index core of the waveguide. In addition, slot-waveguides can be fabricated by employing CMOS compatible materials and technology, enabling miniaturization, integration with electronic, photonic and fluidic components in a chip, and mass production. These advantages have made the use of slot-waveguides for highly sensitive biochemical optical integrated sensors an emerging field. In this paper, recent achievements in slot-waveguide based biochemical sensing will be reviewed. These include slot-waveguide ring resonator based refractometric label-free biosensors, label-based optical sensing, and nano-opto-mechanical sensors.

  11. Alternative irradiation schemes for NIF and LMJ hohlraums

    Science.gov (United States)

    Bourgade, Jean-Luc; Bowen, Christopher; Gauthier, Pascal; Landen, Otto

    2018-02-01

    We explore two alternative irradiation schemes for the large (‘outer’) and small (‘inner’) angle beams that currently illuminate National Ignition Facility (NIF) and Laser Mégajoule cavities. In the first, while the outer laser beams enter through the usual end laser entrance holes (LEH), the inner beams enter through slots along the cavity axis wall, illuminating the back wall of the cavity. This avoids the current interaction of the inner laser beams with the gold wall bubbles generated by the outer beams, which leads to large time-dependent changes in drive symmetry. Another scheme potentially useful for NIF uses only the outer beams. The radiative losses through the slots or from the use of outer beams only are compensated by using a smaller cavity and LEH.

  12. TOPLHA: an accurate and efficient numerical tool for analysis and design of LH antennas

    International Nuclear Information System (INIS)

    Milanesio, D.; Lancellotti, V.; Meneghini, O.; Maggiora, R.; Vecchi, G.; Bilato, R.

    2007-01-01

    Auxiliary ICRF heating systems in tokamaks often involve large complex antennas, made up of several conducting straps hosted in distinct cavities that open towards the plasma. The same holds especially true in the LH regime, wherein the antennas are comprised of arrays of many phased waveguides. Upon observing that the various cavities or waveguides couple to each other only through the EM fields existing over the plasma-facing apertures, we self-consistently formulated the EM problem by a convenient set of multiple coupled integral equations. Subsequent application of the Method of Moments yields a highly sparse algebraic system; therefore formal inversion of the system matrix happens to be not so memory demanding, despite the number of unknowns may be quite large (typically 10 5 or so). The overall strategy has been implemented in an enhanced version of TOPICA (Torino Polytechnic Ion Cyclotron Antenna) and in a newly developed code named TOPLHA (Torino Polytechnic Lower Hybrid Antenna). Both are simulation and prediction tools for plasma facing antennas that incorporate commercial-grade 3D graphic interfaces along with an accurate description of the plasma. In this work we present the new proposed formulation along with examples of application to real life large LH antenna systems

  13. Optical characterization of Jerusalem cross-shaped nanoaperture antenna arrays

    Science.gov (United States)

    Turkmen, Mustafa; Aslan, Ekin; Aslan, Erdem

    2014-03-01

    Recent advances in nanofabrication and computational electromagnetic design techniques have enabled the realization of metallic nanostructures in different shapes and sizes with adjustable resonance frequencies. To date, many metamaterial designs in various geometries with the used of different materials have been presented for the applications of surface plasmons, cloaking, biosensing, and frequency selective surfaces1-5. Surface plasmons which are collective electron oscillations on metal surfaces ensure that plasmonic nanoantennas can be used in many applications like biosensing at infrared (IR) and visible regions. The nanostructure that we introduce has a unit cell that consists of Jerusalem crossshaped nanoaperture on a gold layer, which is standing on suspended SiNx, Si or glass membranes. The proposed nanoaperture antenna array has a regular and stable spectral response. In this study, we present sensitivity of the resonance characteristics of Jerusalem cross-shaped nanoaperture antenna arrays to the changes in substrate parameters and metal thickness. We demonstrate that resonance frequency values can be adjusted by changing the thicknesses and types of the dielectric substrate and the metallic layer. Numerical calculations on spectral response of the nanoantenna array are performed by using Finite Difference Time Domain (FDTD) method6. The results of the simulations specify that resonance frequencies, the reflectance and transmittance values at resonances, and the band gap vary by the change of substrate parameters and metal thicknesses. These variations is a sign of that the proposed nanoantenna can be employed for sensing applications.

  14. WDM cross-connect cascade based on all-optical wavelength converters for routing and wavelength slot interchanging using a reduced number of internal wavelengths

    DEFF Research Database (Denmark)

    Pedersen, Rune Johan Skullerud; Mikkelsen, Benny; Jørgensen, Bo Foged

    1998-01-01

    interchanging can be used to create a robust and nonblocking OXC. However, for an OXC with n fiber inlets each carrying m wavelengths the OXC requires n×m internal wavelengths, which constrains the size of the cross-connect. In this paper we therefore propose and demonstrate an architecture that uses a reduced......Optical transport layers need rearrangeable wavelength-division multiplexing optical cross-connects (OXCs) to increase the capacity and flexibility of the network. It has previously been shown that a cross-connect based on all-optical wavelength converters for routing as well as wavelength slot...... set of internal wavelengths without sacrificing cross-connecting capabilities. By inserting a partly equipped OXC with the new architecture in a 10-Gbit/s re-circulating loop setup we demonstrate the possibility of cascading up to ten OXCs. Furthermore, we investigate the regenerating effect...

  15. A Wideband Dual-Polarized Antenna Using Planar Quasi-Open-Sleeve Dipoles for Base Station Applications

    Directory of Open Access Journals (Sweden)

    Guan-xi Zhang

    2015-01-01

    Full Text Available A wideband dual-polarized antenna for WLAN, WiMAX, and LTE base station applications is presented in this paper. The proposed antenna consists of two pairs of orthogonal planar quasi-open-sleeve dipoles along the centerlines, a balanced feeding structure and a square ground plane. The planar quasi-open-sleeve dipole comprises a pair of bowtie-shaped planar dipoles with two parallel curve parasitic elements. The introduced parallel curve parasitic elements change the path of the current of the original bowtie-shaped planar dipoles at high frequencies and hence wideband characteristic is achieved. Two pairs of the planar quasi-open-sleeve dipoles placed orthogonally further broaden the bandwidth of the antenna with dual-polarization characteristics. The proposed antenna achieves a 10-dB return loss bandwidth from 2.32 to 4.03 GHz (53.9% bandwidth using the planar quasi-open-sleeve dipole structures. The isolation between the two ports remains more than 32 dB in the whole bandwidth. Measured results show that the proposed antenna keeps the cross-polarization under −33 dB and the front-to-back ratio better than 15 dB in the operating band. The antenna has an area of 0.3λ  × 0.3λ at 2.32 GHz making it easy to be extended to an array element.

  16. A Printed Monopole Antenna for Triple-Band WLAN/WiMAX Applications

    Directory of Open Access Journals (Sweden)

    Huiqing Zhai

    2015-01-01

    Full Text Available A new compact design of monopole antenna for triple-band WLAN/WiMAX applications with two band-notches based on broadband antenna is presented. By introducing a stub loaded ground and two new paper clip structures etched on radiation patch, a compact overall dimension 31 mm × 33 mm × 1 mm and three separated operating bands effectively covering 2.4/5.2/5.8 GHz WLAN bands and 2.5/3.5/5.5 GHz WiMAX bands can be achieved. Compared with familiar U type slot, the introduced compact paper clip structure can save about 37% of dimension regions, which could effectively improve efficiency of band-notch formation. Simulated and measured results demonstrate that the proposed antenna has good dipole-like radiation characteristics with appreciable gain across the operating bands. Besides, main parameters of the two etched paper clip structures are investigated to control the positions and bandwidths of the two stop-bands, respectively, on basis of which the three working bands can be adjusted independently.

  17. A Novel Dual Ultrawideband CPW-Fed Printed Antenna for Internet of Things (IoT Applications

    Directory of Open Access Journals (Sweden)

    Qasim Awais

    2018-01-01

    Full Text Available This paper presents a dual-band coplanar waveguide (CPW fed printed antenna with rectangular shape design blocks having ultrawideband characteristics, proposed and implemented on an FR4 substrate. The size of the proposed antenna is just 25 mm × 35 mm. A novel rounded corners technique is used to enhance not only the impedance bandwidth but also the gain of the antenna. The proposed antenna design covers two ultrawide bands which include 1.1–2.7 GHz and 3.15–3.65 GHz, thus covering 2.4 GHz Bluetooth/Wi-Fi band and most of the bands of 3G, 4G, and a future expected 5G band, that is, 3.4–3.6 GHz. Being a very low-profile antenna makes it very suitable for the future 5G Internet of Things (IoT portable applications. A step-by-step design process is carried out to obtain an optimized design for good impedance matching in the two bands. The current densities and the reflection coefficients at different stages of the design process are plotted and discussed to get a good insight into the final proposed antenna design. This antenna exhibits stable radiation patterns on both planes, having low cross polarization and low back lobes with a maximum gain of 8.9 dB. The measurements are found to be in good accordance with the simulated results.

  18. Investigations of Relatively Easy To Construct Antennas With Efficiency in Receiving Schumann Resonances: Preparations for a Miniaturized Reconfigurable ELF Receiver

    Science.gov (United States)

    Farmer, Brian W.; Hannan, Robert C.

    2003-01-01

    Relatively little is known about the cavity between the Earth and the ionosphere, which opens opportunities for technological advances and unique ideas. One effective means to study this cavity is with extremely low frequency (ELF) antennas. Possible applications of these antennas are global weather prediction, earthquake prediction, planetary exploration, communication, wireless transmission of power, or even a free energy source. The superconducting quantum interference device SQUID) and the coil antenna are the two most acceptable receivers discovered for picking up ELF magnetic fields. Both antennas have the potential for size reduction, allowing them to be portable enough for access to space and even for personal ware. With improvements of these antennas and signal processing, insightful analysis of Schumann resonance (SR) can give the science community a band of radio frequency (RF) signals for improving life here on Earth and exploring beyond.

  19. Design of a Microstrip Bowtie Antenna for Indoor Radio-Communications

    Directory of Open Access Journals (Sweden)

    Fraga-Rosales Hector

    2017-01-01

    Full Text Available In this paper, a microstrip bowtie patch antenna (MBPA for wireless indoor communications is carried out. Here, a microstrip transmission-line feed network was designed in order to match the MBPA. The proposed antenna uses a ground plane with the aim of narrowing down the back lobes in comparison with bowtie sheet antennas, which radiation pattern is omni-directional. The far-field pattern of the antenna was simulated using a finite-element numerical algorithm and obtained by interpolation employing near-field equipment. The experimental results are described in detail intending to agree well with the simulated predictions. The antenna was designed, measured and built and its far field performance was evaluated with a 2.11 GHz resonant frequency. The azimuth and elevation antenna patterns, antenna gain and, the matching frequency were the main parameters obtained to analyze the antenna behaviour. The antenna has a gain approximately equal to 8.77 dBi and its beam-widths are higher than 100° in E plane.

  20. Novel Time-domain Ultra-wide Band TEM Horn Antenna for Highway GPR Applications

    Directory of Open Access Journals (Sweden)

    Yin De

    2017-12-01

    Full Text Available Based on transmission line theory and impedance transition, we design an ultra-wideband Transverse ElectroMagnetic (TEM horn antenna that takes advantage of index gradient structure and loading techniques and is optimized for highway Ground Penetrating Radar (GPR applications. We use numerical simulation to analyze the effects of different curved surfaces as an extension of the antenna and further improve the antenna performance by the use of a metallic reflective cavity and distributed resistor loading. We then fabricated an antenna based on the optimization results and determined the Voltage Standing Wave Ratio (VSWR of the antenna to be less than 2 for bandwidths ranging from 0.9–12.6 GHz. The waveform fidelity of the antenna is also good and when we applied this antenna to highway scenarios, it achieved good results.

  1. Radiation quality factor of spherical antennas with material cores

    DEFF Research Database (Denmark)

    Hansen, Troels Vejle; Kim, Oleksiy S.; Breinbjerg, Olav

    2011-01-01

    This paper gives a description of the radiation quality factor and resonances of spherical antennas with material cores. Conditions for cavity and radiating resonances are given, and a theoretical description of the radiation quality factor, as well as simple expressions describing the relative...

  2. Microwave Correlation Measurement Crossed-pair Antennas ...

    African Journals Online (AJOL)

    We propose here new processes, an add and square correlation radiometer and the non-resonant perturbation, which thoroughly investigated for different muscle phantom materials to define the optimum penetration depth of the electromagnetic field at fixed distance between the antennas. Keywords: Microwave correlation ...

  3. Further studies on beam breakup growth reduction by cavity cross-couplings in recirculating accelerators: Effects of long pulse length and multiturn recirculation

    International Nuclear Information System (INIS)

    Colombant, D.; Lau, Y.Y.

    1992-01-01

    Cavity cross-coupling was recently found to reduce beam breakup (BBU) growth in a recirculating accelerator known as the Spiral Line Induction Accelerator (SLIA). Here, we extend the analysis in two prespects: ong beam pulse lengths and a SLIA upgrade geometry which accelerates a 10 kA, 35 ns beam to 25 MeV via a 70 cavity, 7 turn recirculation. We found that when the beam pulse length τ exceeds the beam's transit time τ' between cross-coupled cavities, BBU growth may be worsened as a result of the cross-coupling among cavities. This situation is not unlike other long pulse recirculating accelerators where beam recirculation leads to beam breakup of a regenerative type. Thus, the advantage of BBU reduction by cavity cross-coupling is restricted primarily to beams with τ<τ', a condition envisioned for all SLIA geometries. For the 70 gap, 7 turn SLIA upgrade, we found that cavity cross-coupling may reduce BBU growth up to factors of a thousand when the quality factor Q of the deflecting modes are relatively high (like 100). In these high Q cases, the amount of growth reduction depends on the arrangement and sequence of beam recirculation. For Q < or approx. 20, BBU growth reduction by factors of hundreds is observed, but this reduction is insensitive to the sequence of beam recirculation. The above conclusions were based on simple models of cavity coupling that have been used in conventional microwave literature. Not addressed is the detail design consideration that leads to the desired degree of cavity coupling. (orig.)

  4. Optical cavity cooling of mechanical modes of a semiconductor nanomembrane

    DEFF Research Database (Denmark)

    Usami, Koji; Naesby, A.; Bagci, Tolga

    2012-01-01

    Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and......Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high...

  5. Evaluation of Diversity Antenna Designs Using Ray Tracing, Measured Radiation Patterns, and MIMO Channel Measurements

    Directory of Open Access Journals (Sweden)

    Pal Arindam

    2007-01-01

    Full Text Available This paper presents an evaluation of the MIMO performance of three candidate antenna array designs, each embedded within a PDA footprint, using indoor wideband channel measurements at 5.2 GHz alongside channel simulations. A channel model which employs the plane-wave approximation was used to combine the embedded antenna radiation patterns of the candidate devices obtained from far-field pattern measurements and multipath component parameters from an indoor ray-tracer. The 4-element candidate arrays were each constructed using a different type of antenna element, and despite the diverse element directivities, pattern characteristics, and polarization purities, all three devices were constructed to fully exploit diversity in polarization, space, and angle. Thus, low correlation and high information theoretic capacity was observed in each case. A good match between the model and the measurements is also demonstrated, especially for MIMO subsets of identically or orthogonally polarized linear slot antennas. The interdependencies between the channel XPD, directional spread and pathloss, and the respective impact on channel capacity are also discussed in this paper.

  6. Evaluation of Diversity Antenna Designs Using Ray Tracing, Measured Radiation Patterns, and MIMO Channel Measurements

    Directory of Open Access Journals (Sweden)

    Arindam Pal

    2007-01-01

    Full Text Available This paper presents an evaluation of the MIMO performance of three candidate antenna array designs, each embedded within a PDA footprint, using indoor wideband channel measurements at 5.2 GHz alongside channel simulations. A channel model which employs the plane-wave approximation was used to combine the embedded antenna radiation patterns of the candidate devices obtained from far-field pattern measurements and multipath component parameters from an indoor ray-tracer. The 4-element candidate arrays were each constructed using a different type of antenna element, and despite the diverse element directivities, pattern characteristics, and polarization purities, all three devices were constructed to fully exploit diversity in polarization, space, and angle. Thus, low correlation and high information theoretic capacity was observed in each case. A good match between the model and the measurements is also demonstrated, especially for 2×2 MIMO subsets of identically or orthogonally polarized linear slot antennas. The interdependencies between the channel XPD, directional spread and pathloss, and the respective impact on channel capacity are also discussed in this paper.

  7. Compact Single-Layer Traveling-Wave Antenna DesignUsing Metamaterial Transmission Lines

    Science.gov (United States)

    Alibakhshikenari, Mohammad; Virdee, Bal Singh; Limiti, Ernesto

    2017-12-01

    This paper presents a single-layer traveling-wave antenna (TWA) that is based on composite right/left-handed (CRLH)-metamaterial (MTM) transmission line (TL) structure, which is implemented by using a combination of interdigital capacitors and dual-spiral inductive slots. By embedding dual-spiral inductive slots inside the CRLH MTM-TL results in a compact TWA. Dimensions of the proposed CRLH MTM-TL TWA is 21.5 × 30.0 mm2 or 0.372λ0 × 0.520λ0 at 5.2 GHz (center frequency). The fabricated TWA operates over 1.8-8.6 GHz with a fractional bandwidth greater than 120%, and it exhibits a peak gain and radiation efficiency of 4.2 dBi and 81%, respectively, at 5 GHz. By avoiding the use of lumped components, via-holes or defected ground structures, the proposed TWA design is economic for mass production as well as easy to integrate with wireless communication systems.

  8. A Series-Fed Linear Substrate-Integrated Dielectric Resonator Antenna Array for Millimeter-Wave Applications

    Directory of Open Access Journals (Sweden)

    Ke Gong

    2018-01-01

    Full Text Available A series-fed linear substrate-integrated dielectric resonator antenna array (SIDRAA is presented for millimeter-wave applications, in which the substrate-integrated dielectric resonator antenna (SIDRA elements and the feeding structure can be codesigned and fabricated using the same planar process. A prototype 4 × 1 SIDRAA is designed at Ka-band and fabricated with a two-layer printed circuit board (PCB technology. Four SIDRAs are implemented in the Rogers RT6010 substrate using the perforation technique and fed by a compact substrate-integrated waveguide (SIW through four longitudinal coupling slots within the Rogers RT5880 substrate. The return loss, radiation patterns, and antenna gain were experimentally studied, and good agreement between the measured and simulated results is observed. The SIDRAA example provides a bandwidth of about 10% around 34.5 GHz for 10 dB return loss and stable broadside radiation patterns with the peak gain of 10.5–11.5 dBi across the band.

  9. Advanced LIGO: length sensing and control in a dual recycled interferometric gravitational wave antenna

    International Nuclear Information System (INIS)

    Izumi, Kiwamu; Sigg, Daniel

    2017-01-01

    Length sensing and control is vital for Advanced LIGO and its goal of performing astrophysical searches. The current kilometer scale gravitational wave antennae are dual recycled Michelson interferometers enhanced with Fabry–Perot resonators in the arms. Observation requires the lengths of all optical cavities to be precisely servoed in the vicinity of a resonance using feedback controls. Simultaneously achieving robustness and low-noise is challenging due to cross-couplings between the multiple coupled optical resonators. We analytically derive the Advanced LIGO sensing and control scheme, calculate the effects of radiation pressure forces and review the current strategies of minimizing the coupling of noise into the gravitational wave readout. (paper)

  10. MHD-flow in slotted channels with conducting walls

    International Nuclear Information System (INIS)

    Evtushenko, I.A.; Kirillov, I.R.; Reed, C.B.

    1994-07-01

    A review of experimental results is presented for magnetohydrodynamic (MHD) flow in rectangular channels with conducting walls and high aspect ratios (longer side parallel to the applied magnetic field), which are called slotted channels. The slotted channel concept was conceived at Efremov Institute as a method for reducing MHD pressure drop in liquid metal cooled blanket design. The experiments conducted by the authors were aimed at studying both fully developed MHD-flow, and the effect of a magnetic field on the hydrodynamics of 3-D flows in slotted channels. Tests were carried out on five models of the slotted geometry. A good agreement between test and theoretical results for the pressure drop in slotted channels was demonstrated. Application of a open-quotes one-electrode movable probeclose quotes for velocity measurement permitted measurement of the M-shape velocity profiles in the slotted channels. Suppression of 3-D inertial effects in slotted channels of complex geometry was demonstrated based on potential distribution data

  11. Wideband QAMC reflector's antenna for low profile applications

    Science.gov (United States)

    Grelier, M.; Jousset, M.; Mallégol, S.; Lepage, A. C.; Begaud, X.; LeMener, J. M.

    2011-06-01

    A wideband reflector's antenna based on quasi-artificial magnetic conductor is proposed. To validate the design, an Archimedean spiral has been backed to this new reflector. In comparison to classical solution using absorbent material, the prototype presents a very low thickness of λ/15 at the lowest operating frequency and an improved gain over a 2.4:1 bandwidth. The whole methodology to design this reflector can be applied to other wideband antennas.

  12. Forward Scattering of Loaded and Unloaded Antennas

    DEFF Research Database (Denmark)

    Gustafsson, Mats; Andersen, Jørgen Bach; Kristensson, Gerhard

    2012-01-01

    Forward scattering of antennas is related to antenna performance via the forward-scattering sum rule. The forward-scattering sum rule is an integral identity that shows that a weighted integral of the extinction cross section over all spectrum is proportional to the static polarizability...... of the antenna structure. Here, the forward-scattering sum rule is experimentally verified for loaded, short-circuit, and open-circuit cylindrical dipole antennas. It is also shown that the absorption efficiency cannot be greater than 1/2 for reciprocal linearly polarized lossless matched antennas...... with a symmetric radiation pattern in the forward and backward directions....

  13. Cogging Torque Reduction in Brushless DC Motors Using Slot-Opening Shift

    Directory of Open Access Journals (Sweden)

    SAIED, S. A.

    2009-02-01

    Full Text Available In this paper, two new methods for the stator skew are introduced. In contrary with the conventional stator skew, this paper is concentrate on the slot-opening skew. The simula-tion result by finite element shows a considerable reduction in the cogging torque of the motors, the new methods are applied to. Moreover the simulations justify that the back-EMF shape remains trapezoidal for various skew angles in contrary with that in the conventional skew, this fact makes the method highly applicable in BLDC motors.

  14. Student-Led Objective Tutorial (SLOT) in Medical Education.

    Science.gov (United States)

    Sivagnanam, Gurusamy; Saraswathi, Simansalam; Rajasekaran, Aiyalu

    2006-12-01

    Purpose - To assess an innovative tutoring program named 'Student-Led Objective Tutorial' (SLOT) among undergraduate medical students. Method - The program was conceptualized by the Pharmacology Unit of Faculty of Medicine and Health Sciences, Asian Institute of Medicine Science & Technology (AIMST), Malaysia and implemented in the middle of 2005. A cohort of 246 medical undergraduate students (spread across 5 consecutive batches) participated. Following a brief explanation on the purpose and nature of SLOT, each batch was divided into small groups and was given a reading assignment on 4 previously delivered lecture topics. Each group was asked to prepare 3-5 multiple choice questions (MCQs) of their own in PowerPoint format to be presented, in turns, to the whole class on the day of SLOT. The proceedings were facilitated by 2 lecturers. Student feedback on the efficacy and benefits were assessed through an anonymous self administered questionnaire. Results - About 76% (188) of the students favored SLOT. The acceptance rate of SLOT was higher among males. There was no significant difference between batches in their opinions on whether to pursue SLOT in future. The most prevalent positive comment was that SLOT enhanced learning skills, and the negative comment being, it consumed more time. Conclusions - SLOT is a novel tutorial method which can offset faculty shortage with advantages like enhanced interest among teachers and learners, uniform reach of content, opportunities for group learning, and involvement of visual aids as teaching-learning (T-L) method. SLOT unraveled the students' potential of peer tutoring both inside as well as outside the classroom. Consumer tutors (students) can be tapped as a resource for SLOT for all subjects and courses in healthcare teaching.

  15. Real-time multiplexed digital cavity-enhanced spectroscopy

    International Nuclear Information System (INIS)

    Boyson, Toby K.; Dagdigian, Paul J.; Pavey, Karl D.; Fitzgerald, Nicholas J.; Spence, Thomas G.; Moore, David S.; Harb, Charles C.

    2015-01-01

    Cavity-enhanced spectroscopy is a sensitive optical absorption technique but one where the practical applications have been limited to studying small wavelength ranges. In addition, this Letter shows that wideband operation can be achieved by combining techniques usually reserved for the communications community with that of cavity-enhanced spectroscopy, producing a multiplexed real-time cavity-enhanced spectrometer. We use multiple collinear laser sources operating asynchronously and simultaneously while being detected on a single photodetector. This is synonymous with radio frequency (RF) cellular systems in which signals are detected on a single antenna but decoded uniquely. Here, we demonstrate results with spectra of methyl salicylate and show parts-per-billion per root hertz sensitivity measured in real-time

  16. A Double Inverted F-Shape Patch Antenna for Dual-Band Operation

    Directory of Open Access Journals (Sweden)

    M. M. Islam

    2014-01-01

    Full Text Available A double inverted F-shape patch antenna is presented for dual-band operation. The proposed antenna is comprised of circular and rectangular slots on a printed circuit board of 40 mm × 40 mm × 1.6 mm with a 50 Ω microstrip transmission line. Commercially available high frequency structural simulator (HFSS based on the finite element method (FEM has been adopted in this investigation. It has a measured impedance bandwidths (2 : 1 VSWR of 18.53% on the lower band and 7.8% on the upper band, respectively. It has achieved stable radiation efficiencies of 79.76% and 80.36% with average gains of 7.82 dBi and 5.66 dBi in the operating frequency bands. Moreover, numerical simulations have been indicated as an important uniformity with measured results.

  17. Progress on Ultra-Wideband (UWB Multi-Antenna radar imaging for MIGA

    Directory of Open Access Journals (Sweden)

    Yedlin Matthew

    2016-01-01

    Full Text Available Progress on the development of the multi-channel, ground penetrating radar imaging system is presented from hardware and software perspectives. A new exponentially tapered slot antenna, with an operating bandwidth from 100 MHz to 1.5 GHz was fabricated and tested using the eight-port vector network analyzer, designed by Rhode and Schwarz Incorporated for this imaging project. An eight element antenna array mounted on two carts with automatic motor drive, was designed for optimal common midpoint (CMP data acquisition. Data acquisition scenarios were tested using the acoustic version of the NORSAR2D seismic ray-tracing software. This package enables the synthesis and analysis of multi-channel, multi-offset data acquisitions comprising more than a hundred thousand traces. Preliminary processing is in good agreement with published bistatic ground-penetrating radar images obtained in the tunnels of the Low-noise Underground Laboratory (LSBB at Rustrel, France.

  18. Circularly polarized triple band glass shaped monopole patch antenna with metallic reflector for bluetooth & wireless applications

    Energy Technology Data Exchange (ETDEWEB)

    Jangid, K. G.; Kulhar, V. S. [Department of Physics, Manipal University Jaipur, Jaipur-303007 (India); Choudhary, N.; Jain, P.; Sharma, B. R.; Saini, J. S.; Bhatnagar, D., E-mail: dbhatnagar-2000@rediffmail.com [Microwave Lab, Department of Physics, University of Rajasthan, Jaipur-302004 (India)

    2016-03-09

    This paper presents the design and performance of strip line fed glass shaped monopole patch antenna having with overall size 30mm × 30 mm × 1.59 mm. In the patch; an eight shaped slot and in the ground plane an eight shaped ring are introduced. A metallic ground plane is also introduced at appropriate location beneath the ground plane. The proposed antenna is simulated by applying CST Microwave Studio simulator. Antenna provides circularly polarized radiations, triple broad impedance bandwidth of 203MHz (2.306GHz to 2.510GHz), 42MHz (2.685GHz to 2.757GHz) & GHz (3.63 GHz to 6.05 GHz), high flat gain (close to 5dBi) and good radiation properties in the desired frequency range. This antenna may be a very useful tool for 2.45GHz Bluetooth communication band as well as for 2.4GHz/5.2 GHz /5.8 GHz WLAN bands & 3.7GHz/5.5 GHz Wi-Max bands.

  19. Excitation of the Magnetospheric Cavity by Space-Based ELF/VLF Transmitters

    National Research Council Canada - National Science Library

    Bell, Timothy F; Inan, Umran; Kulkarni, P

    2004-01-01

    During the period of performance Stanford University: 1. Developed an analytical model describing the distribution of current along a dipole antenna radiating ELF/VLF waves in the magnetospheric cavity...

  20. 47 CFR 101.115 - Directional antennas.

    Science.gov (United States)

    2010-10-01

    ... Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE... The minimum front-to-back ratio shall be 38 dBi. 13 Mobile, except aeronautical mobile, stations need... cases of potential interference, an antenna will not be considered to meet Standard A unless the...

  1. Slotting allowances to coordinate manufacturers’ retail sales effort

    OpenAIRE

    Foros, Øystein; Kind, Hans Jarle; Sand, Jan Yngve

    2007-01-01

    Slotting allowances are fees paid by manufacturers to get access to retailers’ shelf space. Although the main attention towards slotting allowances has been within the grocery industry, slotting allowances have also been applied within e.g. e-commerce and mobile telephony. In these industries we observe that distributors have large market power due to their control of access to customers. We analyse how shifting bargaining power from manufacturers to retailers and the use of slotting allowanc...

  2. Active patch antennas for transponder applications

    Energy Technology Data Exchange (ETDEWEB)

    Biffi Gentili, G; Avitabile, G; Bonifacio, F; Salvador, C [Florence Univ. (Italy). Dip. di Ingegneria Elettronica

    1996-01-01

    The paper deals with two patch antenna structures that are mainly taught for short range link and non-contact identification system (RFID). The proposed antennas were developed by starting from an original concept of cross-polarization usefully applicable, in compliance with european for transponder applications are described and experimental results are reported.

  3. Back-action evasion and squeezing of a mechanical resonator using a cavity detector

    Energy Technology Data Exchange (ETDEWEB)

    Clerk, A A [Department of Physics, McGill University, Montreal, Quebec, H3A 2T8 (Canada); Marquardt, F [Department of Physics, Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, 80333 Munich (Germany); Jacobs, K [Department of Physics, University of Massachussets at Boston, Boston, MA 02125 (United States)], E-mail: aashish.clerk@mcgill.ca, E-mail: florian.marquardt@physik.uni-muenchen.de, E-mail: kjacobs@cs.umb.edu

    2008-09-15

    We study the quantum measurement of a cantilever using a parametrically coupled electromagnetic cavity which is driven at the two sidebands corresponding to the mechanical motion. This scheme, originally due to Braginsky et al (Braginsky V, Vorontsov Y I and Thorne K P 1980 Science 209 547), allows a back-action free measurement of one quadrature of the cantilever's motion, and hence the possibility of generating a squeezed state. We present a complete quantum theory of this system, and derive simple conditions on when the quantum limit on the added noise can be surpassed. We also study the conditional dynamics of the measurement, and discuss how such a scheme (when coupled with feedback) can be used to generate and detect squeezed states of the oscillator. Our results are relevant to experiments in optomechanics, and to experiments in quantum electromechanics employing stripline resonators coupled to mechanical resonators.

  4. Wireless OAM transmission system based on elliptical microstrip patch antenna.

    Science.gov (United States)

    Chen, Jia Jia; Lu, Qian Nan; Dong, Fei Fei; Yang, Jing Jing; Huang, Ming

    2016-05-30

    The multiplexing transmission has always been a focus of attention for communication technology. In this paper, the radiation characteristics of circular microstrip patch antenna was firstly analyzed based on cavity model theory, and then spiral beams carrying orbital angular momentum (OAM) were generated, using elliptical microstrip patch antenna, with a single feed probe instead of a standard circular patch with two feedpoints. Moreover, by combining the proposed elliptic microstrip patch antenna with Universal Software Radio Peripheral (USRP), a wireless OAM transmission system was established and the real-time transmission of text, image and video in a real channel environment was realized. Since the wireless OAM transmission has the advantage of good safety and high spectrum utilization efficiency, this work has theoretical significance and potential application.

  5. Design and Development of Aerogel-Based Antennas for Aerospace Applications: A Final Report to the NARI Seedling

    Science.gov (United States)

    Meador, Mary Ann B.; Miranda, Felix A.

    2014-01-01

    As highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties, polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aircraft antenna systems. While they have been aggressively explored for thermal insulation, barely any effort has been made to leverage these materials for antennas or other applications that take advantage of their aforementioned attributes. In Phase I of the NARI Seedling Project, we fabricated PI aerogels with properties tailored to enable new antenna concepts with performance characteristics (wide bandwidth and high gain) and material properties (low density, environmental stability, and robustness) superior to the state of practice (SOP). We characterized electromagnetic properties, including permittivity, reflectivity, and propagation losses for the aerogels. Simple, prototype planar printed circuit patch antennas from down-selected aerogel formulations were fabricated by molding the aerogels to net shapes and by gold-metalizing the pattern onto the templates via electron beam evaporation in a clean room environment. These aerogel based antennas were benchmarked against current antenna SOP, and exhibited both broader bandwidth and comparable or higher gain performance at appreciably lower mass. Phase II focused on the success of the Phase I results pushing the PI aerogel based antenna technology further by exploring alternative antenna design (i.e., slot coupled antennas) and by examining other techniques for fabricating the antennas including ink jet printing with the goal of optimizing antenna performance and simplifying production. We also examined new aerogel formulations with better moisture and solvent resistance to survive processing conditions. In addition, we investigated more complex antenna designs including passive phased arrays such as 2x4 and 4x8 element arrays to assess the scalability of the aerogel antenna concept. Furthermore, we

  6. Analysis of the crystalline characteristics of nc-Si:H thin film using a hyperthermal neutral beam generated by an inclined slot-excited antenna

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Bae; Kim, Young-Woo; Kim, Dae Chul; Kim, Jongsik; Hong, Seung Pyo; Yoo, Suk Jae; Oh, Kyoung Suk, E-mail: ksoh@nfri.re.kr

    2013-11-29

    The deposition of hydrogenated nano-crystal silicon (nc-Si:H) thin film for manufacturing quantum dot solar cells, which has received attention due to the use of this film third-generation solar cells, is studied here. A hyperthermal neutral beam (HNB) generated by an inclined slot-excited antenna plasma source is used to reduce damage to the silicon thin film and deposition of the crystalline thin film is carried out on a substrate at a low temperature (< 200 °C). The size and the crystalline fraction of the nc-Si:H of the deposited thin film were analyzed by scanning transmission electron microscopy and a Raman microscope. As a result, silicon crystals 1–10 nm in size were observed in the amorphous silicon matrix. According to previous studies, the size and the crystalline fraction of nc-Si:H in deposited thin films increase as the hydrogen flow rate is increased. However, the increment of hydrogen flow rate decreases the deposition rate rapidly. The size and the crystalline fraction of nc-Si:H are adjustable by varying the substrate temperature and HNB energy without a change of the hydrogen flow rate. There are optimum conditions between the HNB energy and the substrate temperature for an appropriate amount of nc-Si:H in silicon thin film. - Highlights: • The appropriate hyperthermal neutral beam energy seems to assist film formation. • The Si crystal size can be adjusted by varying hyperthermal neutral beam energy. • The nc-Si:H 1 ∼ 10 in nm size was observed in the amorphous silicon matrix.

  7. Ultra-Wideband, Dual-Polarized, Beam-Steering P-Band Array Antenna

    Science.gov (United States)

    duToit, Cornelis

    2014-01-01

    A dual-polarized, wide-bandwidth (200 MHz for one polarization, 100 MHz for the orthogonal polarization) antenna array at P-band was designed to be driven by NASA's EcoSAR digital beam former. EcoSAR requires two wide P-band antenna arrays mounted on the wings of an aircraft, each capable of steering its main beam up to 35deg off-boresight, allowing the twin radar beams to be steered at angles to the flight path. The science requirements are mainly for dual-polarization capability and a wide bandwidth of operation of up to 200 MHz if possible, but at least 100 MHz with high polarization port isolation and low cross-polarization. The novel design geometry can be scaled with minor modifications up to about four times higher or down to about half the current design frequencies for any application requiring a dual-polarized, wide-bandwidth steerable antenna array. EcoSAR is an airborne interferometric P-band synthetic aperture radar (SAR) research application for studying two- and three-dimensional fine-scale measurements of terrestrial ecosystem structure and biomass, which will ultimately aid in the broader study of the carbon cycle and climate change. The two 2×8 element Pband antenna arrays required by the system will be separated by a baseline of about 25 m, allowing for interferometry measurements. The wide 100-to- 200-MHz bandwidth dual-polarized beams employed will allow the determination of the amount of biomass and even tree height on the ground. To reduce the size of the patches along the boresight dimension in order to fit them into the available space, two techniques were employed. One technique is to add slots along the edges of each patch where the main electric currents are expected to flow, and the other technique is to bend the central part of the patch away from the ground plane. The latter also facilitates higher mechanical rigidity. The high port isolation of more than 40 dB was achieved by employing a highly symmetrical feed mechanism for each

  8. 60 GHz system-on-chip (SoC) with built-in memory and an on-chip antenna

    KAUST Repository

    Ghaffar, Farhan A.

    2014-04-01

    A novel 60 GHz transmitter SoC with an on-chip antenna and integrated memory in CMOS 65 nm technology is presented in this paper. This highly integrated transmitter design can support a data rate of 2 GBPS with a transmission range of 1 m. The transmitter consists of a fundamental frequency 60 GHz PLL which covers the complete ISM band. The modulator following the PLL can support both BPSK and OOK modulation schemes. Both stored data on the integrated memory or directly from an external source can be transmitted. A tapered slot on chip antenna is integrated with the power amplifier to complete the front end of the transmitter design. Size of the complete transmitter with on-chip antenna is only 1.96 mm × 1.96 mm. The core circuits consume less than 100 mW of power. The high data rate capability of the design makes it extremely suitable for bandwidth hungry applications such as unencrypted HD video streaming and transmission.

  9. 60 GHz system-on-chip (SoC) with built-in memory and an on-chip antenna

    KAUST Repository

    Ghaffar, Farhan A.; Arsalan, Muhammad; Cheema, Hammad; Salama, Khaled N.; Shamim, Atif

    2014-01-01

    A novel 60 GHz transmitter SoC with an on-chip antenna and integrated memory in CMOS 65 nm technology is presented in this paper. This highly integrated transmitter design can support a data rate of 2 GBPS with a transmission range of 1 m. The transmitter consists of a fundamental frequency 60 GHz PLL which covers the complete ISM band. The modulator following the PLL can support both BPSK and OOK modulation schemes. Both stored data on the integrated memory or directly from an external source can be transmitted. A tapered slot on chip antenna is integrated with the power amplifier to complete the front end of the transmitter design. Size of the complete transmitter with on-chip antenna is only 1.96 mm × 1.96 mm. The core circuits consume less than 100 mW of power. The high data rate capability of the design makes it extremely suitable for bandwidth hungry applications such as unencrypted HD video streaming and transmission.

  10. Stereoscopic display in a slot machine

    Science.gov (United States)

    Laakso, M.

    2012-03-01

    This paper reports the results of a user trial with a slot machine equipped with a stereoscopic display. The main research question was to find out what kind of added value does stereoscopic 3D (S-3D) bring to slot games? After a thorough literature survey, a novel gaming platform was designed and implemented. Existing multi-game slot machine "Nova" was converted to "3DNova" by replacing the monitor with an S-3D display and converting six original games to S-3D format. To evaluate the system, several 3DNova machines were put available for players for four months. Both qualitative and quantitative analysis was carried out from statistical values, questionnaires and observations. According to the results, people find the S-3D concept interesting but the technology is not optimal yet. Young adults and adults were fascinated by the system, older people were more cautious. Especially the need to wear stereoscopic glasses provide a challenge; ultimate system would probably use autostereoscopic technology. Also the games should be designed to utilize its full power. The main contributions of this paper are lessons learned from creating an S-3D slot machine platform and novel information about human factors related to stereoscopic slot machine gaming.

  11. Metasurface Reflector (MSR) Loading for High Performance Small Microstrip Antenna Design.

    Science.gov (United States)

    Ahsan, Md Rezwanul; Islam, Mohammad Tariqul; Ullah, Mohammad Habib; Singh, Mandeep Jit; Ali, Mohd Tarmizi

    2015-01-01

    A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR) structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15) is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%), 467 to 606 MHz (29%) and 758 MHz to 1062 MHz (40%) for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11WLAN (5.2/5.8 GHz) applications.

  12. S-parameters for weakly excited slots

    DEFF Research Database (Denmark)

    Albertsen, Niels Christian

    1999-01-01

    A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed......A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed...

  13. A satellite-tracking millimeter-wave reflector antenna system for mobile satellite-tracking

    Science.gov (United States)

    Densmore, Arthur C.; Jamnejad, Vahraz; Woo, Kenneth E.

    1995-03-01

    A miniature dual-band two-way mobile satellite tracking antenna system mounted on a movable ground vehicle includes a miniature parabolic reflector dish having an elliptical aperture with major and minor elliptical axes aligned horizontally and vertically, respectively, to maximize azimuthal directionality and minimize elevational directionality to an extent corresponding to expected pitch excursions of the movable ground vehicle. A feed-horn has a back end and an open front end facing the reflector dish and has vertical side walls opening out from the back end to the front end at a lesser horn angle and horizontal top and bottom walls opening out from the back end to the front end at a greater horn angle. An RF circuit couples two different signal bands between the feed-horn and the user. An antenna attitude controller maintains an antenna azimuth direction relative to the satellite by rotating it in azimuth in response to sensed yaw motions of the movable ground vehicle so as to compensate for the yaw motions to within a pointing error angle. The controller sinusoidally dithers the antenna through a small azimuth dither angle greater than the pointing error angle while sensing a signal from the satellite received at the reflector dish, and deduces the pointing angle error from dither-induced fluctuations in the received signal.

  14. Slot Machine Response Frequency Predicts Pathological Gambling

    DEFF Research Database (Denmark)

    Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

    2013-01-01

    Slot machines are among the most addictive forms of gambling, and pathological gambling slot machine players represent the largest group of treatment seekers, accounting for 35% to 93% of the population. Pathological gambling sufferers have significantly higher response frequency (games / time......) on slot machines compared with non-problem gamblers, which may suggest increased reinforcement of the gambling behavior in pathological gambling. However, to date it is unknown whether or not the increased response frequency in pathological gambling is associated with symptom severity of the disorder....... This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...

  15. Modeling of the effect of tool wear per discharge estimation error on the depth of machined cavities in micro-EDM milling

    DEFF Research Database (Denmark)

    Puthumana, Govindan; Bissacco, Giuliano; Hansen, Hans Nørgaard

    2017-01-01

    In micro-EDM milling, real time electrode wear compensation based on tool wear per discharge (TWD) estimation permits the direct control of the position of the tool electrode frontal surface. However, TWD estimation errors will cause errors on the tool electrode axial depth. A simulation tool...... is developed to determine the effects of errors in the initial estimation of TWD and its propagation effect with respect to the error on the depth of the cavity generated. Simulations were applied to micro-EDM milling of a slot of 5000 μm length and 50 μm depth and validated through slot milling experiments...... performed on a micro-EDM machine. Simulations and experimental results were found to be in good agreement, showing the effect of errror amplification through the cavity depth....

  16. Transformation from a Single Antenna to a Series Array Using Push/Pull Origami

    Directory of Open Access Journals (Sweden)

    Syed Imran Hussain Shah

    2017-08-01

    Full Text Available We propose a push/pull origami antenna, transformable between a single antenna element and a three-element array. In limited space, the proposed origami antenna can work as a single antenna. When the space is not limited and a higher gain is required, the proposed origami antenna can be transformed to a series antenna array by pulling the frame. In order to push the antenna array back to a single antenna, the frame for each antenna element size must be different. The frame and supporting dielectric materials are built using a three-dimensional (3D printer. The conductive patterns are inkjet-printed on paper. Thus, the proposed origami antenna is built using hybrid printing technology. The 10-dB impedance bandwidth is 2.5–2.65 GHz and 2.48–2.62 GHz for the single-antenna and array mode, respectively, and the peak gains in the single-antenna and array mode are 5.8 dBi and 7.6 dBi, respectively. The proposed antenna can be used for wireless remote-sensing applications.

  17. Transformation from a Single Antenna to a Series Array Using Push/Pull Origami.

    Science.gov (United States)

    Shah, Syed Imran Hussain; Lim, Sungjoon

    2017-08-26

    We propose a push/pull origami antenna, transformable between a single antenna element and a three-element array. In limited space, the proposed origami antenna can work as a single antenna. When the space is not limited and a higher gain is required, the proposed origami antenna can be transformed to a series antenna array by pulling the frame. In order to push the antenna array back to a single antenna, the frame for each antenna element size must be different. The frame and supporting dielectric materials are built using a three-dimensional (3D) printer. The conductive patterns are inkjet-printed on paper. Thus, the proposed origami antenna is built using hybrid printing technology. The 10-dB impedance bandwidth is 2.5-2.65 GHz and 2.48-2.62 GHz for the single-antenna and array mode, respectively, and the peak gains in the single-antenna and array mode are 5.8 dBi and 7.6 dBi, respectively. The proposed antenna can be used for wireless remote-sensing applications.

  18. A three-dimensional algebraic grid generation scheme for gas turbine combustors with inclined slots

    Science.gov (United States)

    Yang, S. L.; Cline, M. C.; Chen, R.; Chang, Y. L.

    1993-01-01

    A 3D algebraic grid generation scheme is presented for generating the grid points inside gas turbine combustors with inclined slots. The scheme is based on the 2D transfinite interpolation method. Since the scheme is a 2D approach, it is very efficient and can easily be extended to gas turbine combustors with either dilution hole or slot configurations. To demonstrate the feasibility and the usefulness of the technique, a numerical study of the quick-quench/lean-combustion (QQ/LC) zones of a staged turbine combustor is given. Preliminary results illustrate some of the major features of the flow and temperature fields in the QQ/LC zones. Formation of co- and counter-rotating bulk flow and shape temperature fields can be observed clearly, and the resulting patterns are consistent with experimental observations typical of the confined slanted jet-in-cross flow. Numerical solutions show the method to be an efficient and reliable tool for generating computational grids for analyzing gas turbine combustors with slanted slots.

  19. Correlated motion of two atoms trapped in a single-mode cavity field

    International Nuclear Information System (INIS)

    Asboth, Janos K.; Domokos, Peter; Ritsch, Helmut

    2004-01-01

    We study the motion of two atoms trapped at distant positions in the field of a driven standing-wave high-Q optical resonator. Even without any direct atom-atom interaction the atoms are coupled through their position dependent influence on the intracavity field. For sufficiently good trapping and low cavity losses the atomic motion becomes significantly correlated and the two particles oscillate in their wells preferentially with a 90 deg. relative phase shift. The onset of correlations seriously limits cavity cooling efficiency, raising the achievable temperature to the Doppler limit. The physical origin of the correlation can be traced back to a cavity mediated crossfriction, i.e., a friction force on one particle depending on the velocity of the second particle. Choosing appropriate operating conditions allows for engineering these long range correlations. In addition this cross-friction effect can provide a basis for sympathetic cooling of distant trapped clouds

  20. Cross-cultural adaptation and validation of the Hungarian version of the Core Outcome Measures Index for the back (COMI Back).

    Science.gov (United States)

    Klemencsics, Istvan; Lazary, Aron; Valasek, Tamas; Szoverfi, Zsolt; Bozsodi, Arpad; Eltes, Peter; Fekete, Tamás Fülöp; Varga, Peter Pal

    2016-01-01

    The Core Outcome Measure Index (COMI) is a short, multidimensional outcome instrument developed for the evaluation of patients with spinal conditions. The aim of this study was to produce a cross-culturally adapted and validated Hungarian version of the COMI Back questionnaire. A cross-cultural adaptation of the COMI into Hungarian was carried out using established guidelines. Low back pain patients completed a booklet of questionnaires containing the Hungarian versions of COMI, Oswestry Disability Index (ODI) and WHO Quality of Life-BREF assessment (WHOQOL-BREF). The validation of the COMI included assessment of its construct validity, reliability, and responsiveness. 145 patients participated in the assessment of reliability and 159 surgically treated patients were included in the responsiveness study. Excellent correlation was found between COMI and ODI scores (rho = 0.83, p cross-cultural adaptation of the COMI into the Hungarian language was successful, resulting in a reliable and valid measurement tool with good clinimetric properties.

  1. Quasi-optical antenna-mixer-array design for terahertz frequencies

    Science.gov (United States)

    Guo, Yong; Potter, Kent A.; Rutledge, David B.

    1992-01-01

    A new quasi-optical antenna-mixer-array design for terahertz frequencies is presented. In the design, antenna and mixer are combined into an entity, based on the technology in which millimeter-wave horn antenna arrays have been fabricated in silicon wafers. It consists of a set of forward- and backward-looking horns made with a set of silicon wafers. The front side is used to receive incoming signal, and the back side is used to feed local oscillator signal. Intermediate frequency is led out from the side of the array. Signal received by the horn array is picked up by antenna probes suspended on thin silicon-oxynitride membranes inside the horns. Mixer diodes will be located on the membranes inside the horns. Modeling of such an antenna-mixer-array design is done on a scaled model at microwave frequencies. The impedance matching, RF and LO isolation, and patterns of the array have been tested and analyzed.

  2. A new fabrication technique for back-to-back varactor diodes

    Science.gov (United States)

    Smith, R. Peter; Choudhury, Debabani; Martin, Suzanne; Frerking, Margaret A.; Liu, John K.; Grunthaner, Frank A.

    1992-01-01

    A new varactor diode process has been developed in which much of the processing is done from the back of an extremely thin semiconductor wafer laminated to a low-dielectric substrate. Back-to-back BNN diodes were fabricated with this technique; excellent DC and low-frequency capacitance measurements were obtained. Advantages of the new technique relative to other techniques include greatly reduced frontside wafer damage from exposure to process chemicals, improved capability to integrate devices (e.g. for antenna patterns, transmission lines, or wafer-scale grids), and higher line yield. BNN diodes fabricated with this technique exhibit approximately the expected capacitance-voltage characteristics while showing leakage currents under 10 mA at voltages three times that needed to deplete the varactor. This leakage is many orders of magnitude better than comparable Schottky diodes.

  3. Influence of Closed Stator Slots on Cogging Torque

    DEFF Research Database (Denmark)

    Ion, Trifu; Leban, Krisztina Monika; Ritchie, Ewen

    2013-01-01

    Cogging torque results due interaction of magnetic field of magnets and stator slots, and have negative effects on permanent magnet machines such as vibrations, noise, torque ripples and problems during turbine start-up and cut-in. In order to reduce cogging torque this paper presents a study...... of influence of closed stator slots on cogging torque using magnetic slot wedges....

  4. Performance of Cross-Layer Design with Antenna Selection and Imperfect Feedback Information in MIMO Systems

    Directory of Open Access Journals (Sweden)

    Xiaoyu Dang

    2012-01-01

    Full Text Available By combining adaptive modulation and automatic repeat request, a cross-layer design (CLD scheme for MIMO system with antenna selection (AS and imperfect feedback is presented, and the corresponding performance is studied. Subject to a target packet loss rate and fixed power constraint, the variable switching thresholds of fading gain are derived. According to these results, and using mathematical manipulation, the average spectrum efficiency (SE and packet error rate (PER of the system are further derived. As a result, closed-form expressions of the average SE and PER are obtained, respectively. These expressions include the expressions under perfect channel state information as special cases and provide good performance evaluation for the system. Numerical results show that the proposed CLD scheme with antenna selection has higher SE than the existing CLD scheme with space-time block coding, and the CLD scheme with variable switching thresholds outperforms that with conventional-fixed switching thresholds.

  5. Metasurface Reflector (MSR Loading for High Performance Small Microstrip Antenna Design.

    Directory of Open Access Journals (Sweden)

    Md Rezwanul Ahsan

    Full Text Available A meander stripline feed multiband microstrip antenna loaded with metasurface reflector (MSR structure has been designed, analyzed and constructed that offers the wireless communication services for UHF/microwave RFID and WLAN/WiMAX applications. The proposed MSR assimilated antenna comprises planar straight forward design of circular shaped radiator with horizontal slots on it and 2D metasurface formed by the periodic square metallic element that resembles the behavior of metamaterials. A custom made high dielectric bio-plastic substrate (εr = 15 is used for fabricating the prototype of the MSR embedded planar monopole antenna. The details of the design progress through numerical simulations and experimental results are presented and discussed accordingly. The measured impedance bandwidth, radiation patterns and gain of the proposed MSR integrated antenna are compared with the obtained results from numerical simulation, and a good compliance can be observed between them. The investigation shows that utilization of MSR structure has significantly broadened the -10 dB impedance bandwidth than the conventional patch antenna: from 540 to 632 MHz (17%, 467 to 606 MHz (29% and 758 MHz to 1062 MHz (40% for three distinct operating bands centered at 0.9, 3.5 and 5.5 GHz. Additionally, due to the assimilation of MSR, the overall realized gains have been upgraded to a higher value of 3.62 dBi, 6.09 dBi and 8.6 dBi for lower, middle and upper frequency band respectively. The measured radiation patterns, impedance bandwidths (S11<-10 dB and gains from the MSR loaded antenna prototype exhibit reasonable characteristics that can satisfy the requirements of UHF/microwave (5.8 GHz RFID, WiMAX (3.5/5.5 GHz and WLAN (5.2/5.8 GHz applications.

  6. Resonant Elements for Tunable Reflectarray Antenna Design

    Directory of Open Access Journals (Sweden)

    M. Y. Ismail

    2012-01-01

    Full Text Available This paper presents an accurate analysis of different configurations of reflectarray resonant elements that can be used for the design of passive and tunable reflectarrays. Reflection loss and bandwidth performances of these reflectarray elements have been analyzed in the X-band frequency range with the Finite Integral Method technique, and the results have been verified by the waveguide scattering parameter measurements. The results demonstrate a reduction in the phase errors offering an increased static linear phase range of 225° which allows to improve the bandwidth performance of single layer reflectarray antenna. Moreover a maximum dynamic phase range of 320° and a volume reduction of 22.15% have been demonstrated for a 10 GHz reflectarray element based on the use of rectangular patch with an embedded circular slot.

  7. Numerical investigation of the LM MHD flows in a curved duct with an FCI with varying slot locations

    International Nuclear Information System (INIS)

    Yang, Jong Hoon; Yan, Yue; Kim, Chang Nyung

    2016-01-01

    Highlights: • This study numerically investigates the liquid-metal magnetohydrodynamic flows in a curved duct with an FCI. • The effects of the location of FCI slot and of the curvature radius on the flow behavior are reviewed. • The influence of the FCI slot position on the equalization of the pressure in the inner fluid region (inside the FCI) and the gap fluid region (outer the FCI) is examined. - Abstract: This study numerically investigates the liquid-metal (LM) magnetohydrodynamic (MHD) flows in a curved duct with an FCI having three different slot locations and having no slot under a uniform magnetic field perpendicular to the duct. The flow velocity, current density, electric potential, Lorentz force, and pressure in different flow situations are presented in detail. The effects of the location of FCI slot and of the curvature radius on the flow behavior are reviewed. The flow field is examined with an introduction of the electric-field component and electro-motive component of the current, allowing us to analyze the interdependency of the flow variables. The effect of the FCI slot position on the equalization of the pressure in the inner fluid region (inside the FCI) and the gap fluid region (outer the FCI) is examined. The result shows that and the case with an FCI slot located in the neutral position yields the smallest pressure gradient in the main flow direction among the cases with an FCI slot, resulting in the smallest pressure drop. Also, in a flow situation with smaller radius of curvature with the FCI slot in the neutral position, the axial velocity near the inner (in terms of the curvature) part of a cross-section is higher than that near the outer part.

  8. Progress on the high-current 704 MHz superconducting RF cavity at BNL

    International Nuclear Information System (INIS)

    Xu, W.; Astefanous, C.; Belomestnykh, S.; Ben-Zvi, I.

    2012-01-01

    The 704 MHz high current superconducting cavity has been designed with consideration of both performance of fundamental mode and damping of higher order modes. A copper prototype cavity was fabricated by AES and delivered to BNL. RF measurements were carried out on this prototype cavity, including fundamental pass-band and HOM spectrum measurements, HOM studies using bead-pull setup, prototyping of antenna-type HOM couplers. The measurements show that the cavity has very good damping for the higher-order modes, which was one of the main goals for the high current cavity design. 3D cavity models were simulated with Omega3P code developed by SLAC to compare with the measurements. The paper describes the cavity design, RF measurement setups and results for the copper prototype. The progress with the niobium cavity fabrication will also be described.

  9. The Evaluation of Pelvic Cross Syndrome in Patients with Non-specific Chronic Low Back Pain

    Directory of Open Access Journals (Sweden)

    Amir Masoud A'rab

    2007-10-01

    Full Text Available Objective: The purpose of this study was the investigation of relationship between muscle imbalance syndrome in the lumbo-pelvic area (Pelvic Cross Syndrome which includes the combination of weakness of phasic muscles and tightness of postural muscles, lordosis and chronic low back pain. Materials & Methods: This study was a comparative - cross-sectional and case – control research. A convenience sample of 600 subjects participated in this study. The size of lordosis, strength of abdominal and gluteal muscles and the extensibility of iliopsoas and back extensor muscles were measured in each group. The best cut-off values obtained from Receiver Operating Characteristic (ROC curve analysis were used to categorize subjects as having weak or tight muscles in accordance with the assumptions. The lumbar lordosis in subjects with and without patterns of muscle impairments, and the association between lordosis and low back pain was assessed. Data were analyzed by using statistical methods such as: ICC, Kolmogroff – Smirnoff, Independent T test and ANOVA. Results: The Findings of this study showed no significant difference in the degree of lordosis in subjects with and without patterns of muscle impairment in pelvic cross syndrome (P=0.38 and no significant difference in the lordosis between subjects with and without low back pain among those with specific patterns of muscle impairment in pelvic cross syndrome (P=0.62. Data also showed no significant association between degree of lordosis and low back pain (P=0.25. Conclusion: The findings of this study did not support the Pelvic Cross Syndrome theory, which indicates certain patterns of muscle impairment would lead to exaggerated LL and LBP. Our data show a relationship between muscle impairment and occurrence of LBP, but probably not via changing the degree of lumbar lordosis as it has been proposed in PCS theory.

  10. G-tunnel pressurized slot-testing evaluations

    International Nuclear Information System (INIS)

    Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a development program to enhance mechanical-type measurements. The program was focused on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of pressurized slot strength testing results and methods. This report contains data interpretation and evaluations. Included are recommendations for future efforts. This third report contains the interpretations of the testing with emphasis on the measurement results as they apply to describing rock behavior. In particular, emphases are placed on (1) normal stress determinations using the flatjack cancellation (FC) method, (2) modulus of deformation determinations, and (3) high pressure investigations. Most of the material in the first two reports is not repeated here. Appropriate data are repeated in tabular form

  11. Numerical Studies on Natural Convection Heat Losses from Open Cubical Cavities

    Directory of Open Access Journals (Sweden)

    M. Prakash

    2013-01-01

    Full Text Available The natural convection heat losses occurring from cubical open cavities are analysed in this paper. Open cubical cavities of sides 0.1 m, 0.2 m, 0.25 m, 0.5 m, and 1 m with constant temperature back wall boundary conditions and opening ratio of 1 are studied. The Fluent CFD software is used to analyse the three-dimensional (3D cavity models. The studies are carried out for cavities with back wall temperatures between 35°C and 100°C. The effect of cavity inclination on the convective loss is analysed for angles of 0° (cavity facing sideways, 30°, 45°, 60°, and 90° (cavity facing vertically downwards. The Rayleigh numbers involved in this study range between 4.5 × 105 and 1.5 × 109. The natural convection loss is found to increase with an increase in back wall temperature. The natural convection loss is observed to decrease with an increase in cavity inclination; the highest convective loss being at 0° and the lowest at 90° inclination. This is observed for all cavities analysed here. Nusselt number correlations involving the effect of Rayleigh number and the cavity inclination angle have been developed from the current studies. These correlations can be used for engineering applications such as electronic cooling, low- and medium-temperature solar thermal systems, passive architecture, and also refrigeration systems.

  12. Energy dissipation of slot-type flip buckets

    Science.gov (United States)

    Wu, Jian-hua; Li, Shu-fang; Ma, Fei

    2018-03-01

    The energy dissipation is a key index in the evaluation of energy dissipation elements. In the present work, a flip bucket with a slot, called the slot-type flip bucket, is theoretically and experimentally investigated by the method of estimating the energy dissipation. The theoretical analysis shows that, in order to have the energy dissipation, it is necessary to determine the sequent flow depth h 1 and the flow speed V 1 at the corresponding position through the flow depth h 2 after the hydraulic jump. The relative flow depth h 2 / h 。 is a function of the approach flow Froude number Fr 。, the relative slot width b/B 。, and the relative slot angle θ/β. The expression for estimating the energy dissipation is developed, and the maximum error is not larger than 9.21%.

  13. Losses Disguised as Wins Affect Game Selection on Multiline Slots.

    Science.gov (United States)

    Graydon, Candice; Stange, Madison; Dixon, Mike J

    2018-05-05

    Multiline slots are exciting games that contain features which make them alluring. One such feature is a loss disguised as a win (LDW); wherein, players win less than they wager (e.g., bet 2 dollars, win back 50 cents), but this net loss is disguised by flashing graphics and winning sounds. Research to date concludes that LDWs are both rewarding and reinforcing. Here, we investigated whether LDWs affect players' game selection. Thirty-two undergraduate students with experience playing slot machines played 100 spins on four games-two had positive payback percentages (115%) and two had negative payback percentages (85%) after 100 spins. For each payback percentage condition, there was a game with no LDWs and a game with a moderate number of LDWs. For the 100 spins, players could choose to play whichever game they wished. They then rated their preference for each game following the 100-spins and chose a game to continue playing. The majority of players preferred playing the positive payback percentage game with LDWs and chose to continue playing this game over the three other games. We conclude that in addition to LDWs being reinforcing and rewarding, LDWs do in fact influence game selection. We conclude that responsible gambling initiatives should educate players about LDWs.

  14. Dual band monopole antenna for WLAN 2.4/5.2/5.8 with truncated ground

    Science.gov (United States)

    Chandan, Bharti, Gagandeep; Srivastava, Toolika; Rai, B. S.

    2018-04-01

    A dual-band mono-pole antenna is proposed for Wireless LAN applications. The WLAN band is obtained by cutting a rectangular ring and a circular slot in the radiating patch. The overall dimension of antenna is 17×16.5×0.8 mmł. The frequency bands obtained are 2.38-2.9 GHz and 4.7-6.1 GHz with ≤ - 10 dB return loss which covers WLAN 2.4/5.2/5.8 GHz bands. The behavior of the antenna is analyzed in terms of radiation pattern, peak realized gain, radiation efficiency and surface current density. It has dipole like radiation pattern with gain of 2.33 - 4.31 dBi for lower frequency band and 4.29 - 5.16 dBi for upper frequency band with radiation efficiency of 95-98% and 93-96% respectively. The parametric analysis is carried out to understand the consequence of the various shape parameters and to get an optimum design. The simulation and measurement gave the results having close agreement.

  15. Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom

    Directory of Open Access Journals (Sweden)

    Tian Hong Loh

    2014-08-01

    Full Text Available This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i an optical fibre; and (ii a metallic coaxial cable.

  16. Revisiting Street Intersections Using Slot-Based Systems.

    Directory of Open Access Journals (Sweden)

    Remi Tachet

    Full Text Available Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs. Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.

  17. Novel Microstrip Patch Antennas with Frequency Agility, Polarization Reconfigurability, Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance

    Science.gov (United States)

    Babakhani, Behrouz

    Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency

  18. 49 CFR 236.809 - Signal, slotted mechanical.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, slotted mechanical. 236.809 Section 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

  19. A Waveguide Transverse Broad Wall Slot Radiating Between Baffles

    DEFF Research Database (Denmark)

    Dich, Mikael; Rengarajan, S.R.

    1997-01-01

    An analysis of the self impedance of waveguide-fed transverse slots radiating between baffles is presented. The region exterior to the slot is treated as a parallel plate (PP) waveguide which radiates into half space through an aperture in an infinite ground plane. The slot problem is analyzed...

  20. A Novel Ancient Coin-Like Fractal Multiband Antenna for Wireless Applications

    Directory of Open Access Journals (Sweden)

    Zhen Yu

    2017-01-01

    Full Text Available This study proposes a novel square-circle structure fractal multibroadband planar antenna, similar to an ancient Chinese coin-like structure, for second generation (2G, third generation (3G, fourth generation (4G, WLAN, and navigation wireless applications. The device is based on the principles and structural features of conventional monopole antenna elements, combined with the advantages of microstrip antennas and fractal geometry. A fractal method was presented for circular nested square slotted structures, similar to an ancient Chinese copper coin. The proposed antenna adapted five iterations on a fractal structure radiator, which covers more than ten mobile applications in three broad frequency bands with a bandwidth of 70% (1.43–2.97 GHz for DCS1800, TD-SCDMA, WCDMA, CDMA2000, LTE33-41, Bluetooth, GPS (Global Positioning System, BDS (BeiDou Navigation Satellite System, GLONSS (Global Navigation Satellite System, GALILEO (Galileo Satellite Navigation System, and WLAN frequency bands, 16.32% (3.32–3.91 GHz for LTE42, LTE43, and WiMAX frequency bands, and 10.92% (4.85–5.41 GHz for WLAN frequency band. The proposed antenna was fabricated on a 1.6 mm thick G10/FR4 substrate with a dielectric constant of 4.4 and a size of 88.5 × 60 mm2. The measurement results reveal that the omnidirectional radiation patterns achieve a gain of 1.16–3.75 dBi and an efficiency of 40–72%. The good agreement between the measurement results and simulation validates the proposed design approach and satisfies the requirements for various wireless applications.

  1. A Two Element Plasma Antenna Array

    Directory of Open Access Journals (Sweden)

    F. Sadeghikia

    2013-10-01

    Full Text Available This theoretical study presents the characteristics of plasma monopole antennas in the VHF/UHF range using finite difference time domain (FDTD simulation. Results show that more broadband characteristics can be obtained by increasing the diameter of the plasma tube and that the minor lobes diminish in intensity as diameter increases. Furthermore, the nulls are replaced by low level radiation. Since the collision frequency, which is a function of gas pressure, represents the loss mechanism of plasma, decreasing its value increases the gain and radar cross section (RCS of the antenna. Theoretical modeling shows that at higher plasma frequencies with respect to the signal frequency, the gain and radar cross section of the plasma antenna are high enough and that the impedance curves are altered as the plasma frequency varies. Using these preliminary studies, mutual impedance and gain of a broadside array of two parallel side-by-side plasma elements is presented.

  2. Frequency Selective Surfaces for extended Bandwidth backing reflector functions

    NARCIS (Netherlands)

    Pasian, M.; Neto, A.; Monni, S.; Ettorre, M.; Gerini, G.

    2008-01-01

    This paper deals with the use of Frequency Selective Surfaces (FSS) to increase the Efficiency × Bandwidth product in Ultra-Wide Band (UWB) antenna arrays whose efficiency is limited by the front-to-back ratio. If the backing reflector is realized in one metal plane solution its location will be

  3. Compact printed high rejection triple band-notch UWB antenna with multiple wireless applications

    Directory of Open Access Journals (Sweden)

    Manish Sharma

    2016-09-01

    Full Text Available In this paper, small printed urn-shape triple notch ultra-wideband (UWB monopole antenna with diverse wireless applications is presented. Notch bands include WiMAX (IEEE802.16 3.30–3.80 GHz, WLAN IEEE802.11a/h/j/n (5.15–5.35 GHz, 5.25–5.35 GHz, 5.47–5.725 GHz, 5.725–5.825 GHz, and X-band downlink satellite system (7.25–7.75 GHz and other multiple wireless services as close range radar (8–12 GHz in X-band & satellite communication (12–18 GHz in Ku-band. By including T-shape stub and etching two C-shaped slots on the radiating patch, triple band-notch function is obtained with measured high band rejection (VSWR = 16.54 at 3.60 GHz, VSWR = 22.35 at 5.64 GHz and VSWR = 6.38 at 7.64 GHz and covers a wide useable fractional bandwidth of 154.56% (2.49–19.41 GHz. In short the antenna offers triple band-notch UWB systems as a compact multifunctional antenna to reduce the number of antennas installed in wireless devices for accessing multiple wireless networks with wide radiation pattern.

  4. A multiband dual-standard MIMO antenna system based on monopoles (4G) and connected slots (5G) for future smart phones

    KAUST Repository

    Ikram, M.; Sharawi, M. S.; Shamim, Atif; Sebak, A.

    2018-01-01

    In this work, a 4G/5G multiple-input multiple-output (MIMO) antenna system is presented for smart phone applications. The 4G antenna operates from 1900 to 3212 MHz and 3517 to 3712 MHz with 1312 (69%) and 195 (5.5%) MHz measured bandwidths

  5. Closed-loop multiple antenna aided wireless communications using limited feedback

    OpenAIRE

    Yang, Du

    2010-01-01

    The aim of this thesis is to study the design of closed-loop multiple antenna aided wireless communications relying on limited feedback. Multiple antennas may be employed either/both at the transmitter or/and at the receiver, here the latter periodically feeds back some information about the time-varying wireless channel using a limited number of bits. Furthermore, the transmitter then pre-processes the signals to be transmitted according to the received feedback information. This closed-loop...

  6. Rectangular-cladding silicon slot waveguide with improved nonlinear performance

    Science.gov (United States)

    Huang, Zengzhi; Huang, Qingzhong; Wang, Yi; Xia, Jinsong

    2018-04-01

    Silicon slot waveguides have great potential in hybrid silicon integration to realize nonlinear optical applications. We propose a rectangular-cladding hybrid silicon slot waveguide. Simulation result shows that, with a rectangular-cladding, the slot waveguide can be formed by narrower silicon strips, so the two-photon absorption (TPA) loss in silicon is decreased. When the cladding material is a nonlinear polymer, the calculated TPA figure of merit (FOMTPA) is 4.4, close to the value of bulk nonlinear polymer of 5.0. This value confirms the good nonlinear performance of rectangular-cladding silicon slot waveguides.

  7. Flow through the nasal cavity of the spiny dogfish, Squalus acanthias

    Science.gov (United States)

    Timm-Davis, L. L.; Fish, F. E.

    2015-12-01

    The nasal cavity of spiny dogfish is a blind capsule with no internal connection to the oral cavity. Water is envisioned to flow through the cavity in a smooth, continuous flow pattern; however, this assumption is based on previous descriptions of the morphology of the olfactory cavity. No experimentation on the flow through the internal nasal cavity has been reported. Morphology of the head of the spiny dogfish ( Squalus acanthias) does not suggest a close external connection between the oral and nasal systems. However, dye visualization showed that there was flow through the nasal apparatus and from the excurrent nostril to the mouth when respiratory flows were simulated. The hydrodynamic flow through the nasal cavity was observed from flow tank experiments. The dorsum of the nasal cavity of shark heads from dead animals was exposed by dissection and a glass plate was glued over of the exposed cavity. When the head was placed in a flow, dye was observed to be drawn passively into the cavity showing a complex, three-dimensional hydrodynamic flow. Dye entered the incurrent nostril, flowed through the nasal lamellae, crossed over and under the nasal valve, and circulated around the nasal valve before exiting the excurrent nostril. When the nasal valve was removed, the dye became stagnant and back flowed out through the incurrent nostril. The single nasal valve has a hydrodynamic function that organizes a coherent flow of water through the cavity without disruption. The results suggest that the morphology of the nasal apparatus in concert with respiratory flow and ambient flows from active swimming can be used to draw water through the olfactory cavity of the shark.

  8. Energy tunneling through narrow waveguide channel and design of small antennas

    Directory of Open Access Journals (Sweden)

    Mitrović Miranda

    2011-01-01

    Full Text Available In this paper we investigate the conditions for energy tunneling through narrow channel obtained by reducing the height of rectangular waveguide. Tunneling of the energy occurs at the frequency for which the effective dielectric permittivity of the channel becomes equal to zero, so it can be treated as an ENZ (epsilon-near-zero metamaterial. We investigated how geometry of the channel and dielectric permittivity affect the transmission coefficient and field density in the channel. Adding slots in the channel, which are placed orthogonally to the wave propagation, we designed a small antenna with directivity of 5.44 dBi at the frequency of 3 GHz.

  9. Slot Optimization Design of Induction Motor for Electric Vehicle

    Science.gov (United States)

    Shen, Yiming; Zhu, Changqing; Wang, Xiuhe

    2018-01-01

    Slot design of induction motor has a great influence on its performance. The RMxprt module based on magnetic circuit method can be used to analyze the influence of rotor slot type on motor characteristics and optimize slot parameters. In this paper, the authors take an induction motor of electric vehicle for a typical example. The first step of the design is to optimize the rotor slot by RMxprt, and then compare the main performance of the motor before and after the optimization through Ansoft Maxwell 2D. After that, the combination of optimum slot type and the optimum parameters are obtained. The results show that the power factor and the starting torque of the optimized motor have been improved significantly. Furthermore, the electric vehicle works at a better running status after the optimization.

  10. Design of dual band FSS by using quadruple L-slot technique

    Science.gov (United States)

    Fauzi, Noor Azamiah Md; Aziz, Mohamad Zoinol Abidin Abd.; Said, Maizatul Alice Meor; Othman, Mohd Azlishah; Ahmad, Badrul Hisham; Malek, Mohd Fareq Abd

    2015-05-01

    This paper presents a new design of dual band frequency selective surface (FSS) for band pass microwave transmission application. FSS can be used on energy saving glass to improve the transmission of wireless communication signals through the glass. The microwave signal will be attenuate when propagate throughout the different structure such as building. Therefore, some of the wireless communication system cannot be used in the optimum performance. The aim of this paper is designed, simulated and analyzed the new dual band FSS structure for microwave transmission. This design is based on a quadruple L slot combined with cross slot to produce pass band at 900 MHz and 2.4 GHz. The vertical of pair inverse L slot is used as the band pass for the frequency of 2.4GHz. While, the horizontal of pair inverse L slot is used as the band pass at frequency 900MHz. This design is simulated and analyzed by using Computer Simulation Technology (CST) Microwave Studio (MWS) software. The characteristics of the transmission (S21) and reflection (S11) of the dual band FSS were simulater and analyzed. The bandwidth of the first band is 118.91MHz which covered the frequency range from 833.4MHz until 952.31MHz. Meanwhile, the bandwidth for the second band is 358.84MHz which covered the frequency range from 2.1475GHz until 2.5063GHz. The resonance/center frequency of this design is obtained at 900MHz with a 26.902dB return loss and 2.37GHz with 28.506dB a return loss. This FSS is suitable as microwave filter for GSM900 and WLAN 2.4GHz application.

  11. Predictors of return rate discrimination in slot machine play.

    Science.gov (United States)

    Coates, Ewan; Blaszczynski, Alex

    2014-09-01

    The purpose of this study was to investigate the extent to which accurate estimates of payback percentages and volatility combined with prior learning, enabled players to successfully discriminate between multi-line/multi-credit slot machines that provided differing rates of reinforcement. The aim was to determine if the capacity to discriminate structural characteristics of gaming machines influenced player choices in selecting 'favourite' slot machines. Slot machine gambling history, gambling beliefs and knowledge, impulsivity, illusions of control, and problem solving style were assessed in a sample of 48 first year undergraduate psychology students. Participants were subsequently exposed to a choice paradigm where they could freely select to play either of two concurrently presented PC-simulated slot machines programmed to randomly differ in expected player return rates (payback percentage) and win frequency (volatility). Results suggest that prior learning and cognitions (particularly gambler's fallacy) but not payback, were major contributors to the ability of a player to discriminate volatility between slot machines. Participants displayed a general tendency to discriminate payback, but counter-intuitively placed more bets on the slot machine with lower payback percentage rates.

  12. Bring Back Our Girls, Social Mobilization: Implications for Cross-Cultural Research

    Science.gov (United States)

    Olutokunbo, Adekalu Samuel; Suandi, Turiman; Cephas, Oluwaseyitan Rotimi; Abu-Samah, Irza Hanie

    2015-01-01

    Social mobilization is a proactive measure for community development that salvages the society from destruction and disaster. From sociological perspective, this paper discusses the concept of social mobilization and its implications for cross-cultural research. To do this, the study uses the "Bring Back Our Girls" Global Campaign, as…

  13. Low back pain among nurses in Slovenian hospitals: cross-sectional study.

    Science.gov (United States)

    Skela-Savič, B; Pesjak, K; Hvalič-Touzery, S

    2017-12-01

    The study investigated the prevalence and factors predicting low back pain among nurses in Slovenian hospitals. The risk factors for low back pain are physical and psychosocial. Implementation of interventions for reducing low back pain calls for management support, accessible equipment, education, knowledge and risk assessment. Low back pain prevalence and incidence among healthcare workers is very high compared to the general population and is a strong risk factor for long-term sickness absence. A cross-sectional study design was utilized. We used validated instruments: Nordic Musculoskeletal Disorder Questionnaire, Stanford Presenteeism Scale and Perceived Stress Scale. The sample included 1744 nursing employees from 16 Slovenian hospitals, ranging from practical nurses, registered nurses, nurses with a bachelor's degree and those with a master's degree. Results revealed a prevalence of low back pain among 85.9% of respondents. Relevant risk factors included female gender, age, length of employment, years in current position, shift work and the number of nurses per shift. In the regression model, factors predicting low back pain included presenteeism with a negative effect on work, presenteeism and maintaining work productivity, inability to control daily life, number of nurses per shift and respondents' age. Future activities should be oriented towards eliminating or reducing risks for low back pain incidents and towards different strategies, guidelines and actions which empower individuals and provide knowledge to manage and prevent low back pain. Slovenian healthcare system planning needs a national strategy to successfully promote LBP preventive and controlling strategies. Management can plan preventive and curative measures to reduce low back pain prevalence among nursing personnel. Management should also implement policies reflecting research findings. © 2017 International Council of Nurses.

  14. Mode Theory of Multi-Armed Spiral Antennas and Its Application to Electronic Warfare Antennas

    Science.gov (United States)

    Radway, Matthew J.

    with exceptionally stable and clean radiation patterns without use of an absorbing cavity. The multiarming technique allows the spiral to retain its pattern integrity at frequencies well below those of comparable two-armed spiral antennas. A quadrifilar helix-type of end-loading is applied to the end of the spiral, resulting in dramatically-improved low-frequency gain. Careful application of resistive end-loading allows good impedance matching at frequencies as low as one-half of the Mode 1 cutoff frequency, while providing acceptable radiation efficiency due to effective use of the available antenna volume. A novel dual-layering technique for reducing the spiral's modal impedance is presented, allowing the antenna to present a good impedance match to a 50 ohm system. The third application of mode theory has been to exploit the wideband multi-mode capability of the multi-armed spiral antenna to implement a simple wide-band radiation pattern nulling technique on a multi-armed spiral antenna. It is shown that wideband nulling is possible and that, in contrast to traditional array antennas, grating lobes do not appear even over extremely wide bandwidths. Simple techniques for addressing the phenomenon of null rotation with frequency are discussed. Finally, mode theory has been used to analyze beamformer non-idealities. This has led to the revelation that the spectral distribution of beamformer errors is at least as important as the magnitude of those errors. Proper choice of beamformer topology can result in noticeable improvement in the antenna performance.

  15. [Influence of slot size on torque control].

    Science.gov (United States)

    Tian, Jun; Liu, Zhong-Hao; Zhang, Ding; Wu, Chuan-Jun

    2009-12-01

    To study the influence of two slot size brackets on torque control when teeth interacted in the same arch. After the upper arch was aligned and leveled in Typodont study, the inclinations of upper teeth 5 +/- 5 were measured when 0.457 2 mm x 0.635 0 mm OPA-K brackets and 0.558 8 mmx0.711 2 mm OPA-K brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire. This experiment was duplicated 10 times. The inclin of each tooth were transformed to the absolute values of the torque play angle psi by computing program, and paired-t test was used. The two kinds of slot size brackets were different with statistical significance on torque control. When the brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire, the absolute values of the angle psi in 0.558 8 mm x 0.711 2 mm and 0.457 2 mm x 0.635 0 mm slot size brackets were 6.140 degrees +/- 3.758 degrees and 2.608 degrees +/- 1.479 degrees respectively, and the average difference of that between the two slot size brackets was 3.532 degrees. The absolute values of the angle psi in the upper left and right canine brackets were 2.560 degrees +/- 2.605 degrees, 4.230 degrees +/- 2.817 degrees, 1.260 degrees +/- 0.747 degrees and 2.070 degrees +/- 0.663 degrees respectively, and average differences between them were smaller than that in the other teeth. There was difference between the two kinds of slot size brackets on torque control, and 0.457 2 mm x 0.635 0 mm slot size bracket controls torque better when filled with the same size wire. In this study, the teeth interaction in the same arch probably caused the result that the difference of two slot size brackets on torque control was less than the study results of the theory calculations and material studys before.

  16. Design of UAVs-Based 3D Antenna Arrays for a Maximum Performance in Terms of Directivity and SLL

    Directory of Open Access Journals (Sweden)

    Jesus Garza

    2016-01-01

    Full Text Available This paper presents a design of UAVs-based 3D antenna arrays for a maximum performance in terms of directivity and side lobe level (SLL. This paper illustrates how to model the UAVs formation flight using 3D nonuniform antenna arrays. This design of 3D antenna arrays considers the optimization of the positions of the antenna elements to model the UAVs formation flight. In this case, a disk patch antenna is chosen to be used as element in each UAV. The disk patch antenna is formulated by the well-known cavity model. The synthesis process is carried out by the method of Differential Evolution for Multiobjective Optimization (DEMO. Furthermore, a comparison of the performance of 3D nonuniform antenna arrays is provided with respect to the most conventional arrays (circular, planar, linear, and the cubic for UAVs formation flight.

  17. Compact Low Frequency Radio Antenna

    Science.gov (United States)

    Punnoose, Ratish J.

    2008-11-11

    An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

  18. The electromagnetic interferent antennae for gravitational waves detection

    International Nuclear Information System (INIS)

    Kulak, A.

    1984-01-01

    An electromagnetic wave propagating in the toroidal waveguide is considered as an electromagnetic gravitational antenna. An interferometric method is applied to measure the disturbances of phase of the electromagnetic field caused by the incident gravitational wave. The calculations presented take into account the dispersive and dissipative phenomena occurring during the interaction between electromagnetic and gravitational fields. The active cross-section of the antenna interacting with coherent and pulsed gravitational radiation is estimated. Experimental possibilities presently available are discussed. Limiting fluxes in the astrophysical range of frequencies measured by the interferometric electromagnetic antenna are a factor of ten or so smaller than in the case of a classic mechanical antenna. Moreover the antenna could be used for carrying out a gravitational Hertz experiment. (author)

  19. Antenna Design Considerations for the Advanced Extravehicular Mobility Unit

    Science.gov (United States)

    Bakula, Casey J.; Theofylaktos, Onoufrios

    2015-01-01

    NASA is designing an Advanced Extravehicular Mobility Unit (AEMU)to support future manned missions beyond low-Earth orbit (LEO). A key component of the AEMU is the communications assembly that allows for the wireless transfer of voice, video, and suit telemetry. The Extravehicular Mobility Unit (EMU) currently used on the International Space Station (ISS) contains a radio system with a single omni-directional resonant cavity antenna operating slightly above 400 MHz capable of transmitting and receiving data at a rate of about 125 kbps. Recent wireless communications architectures are calling for the inclusion of commercial wireless standards such as 802.11 that operate in higher frequency bands at much higher data rates. The current AEMU radio design supports a 400 MHz band for low-rate mission-critical data and a high-rate band based on commercial wireless local area network (WLAN) technology to support video, communication with non-extravehicular activity (EVA) assets such as wireless sensors and robotic assistants, and a redundant path for mission-critical EVA data. This paper recommends the replacement of the existing EMU antenna with a new antenna that maintains the performance characteristics of the current antenna but with lower weight and volume footprints. NASA has funded several firms to develop such an antenna over the past few years, and the most promising designs are variations on the basic patch antenna. This antenna technology at UHF is considered by the authors to be mature and ready for infusion into NASA AEMU technology development programs.

  20. The Gambling Reducing Slot Machine

    DEFF Research Database (Denmark)

    Callesen, Mette Buhl; Thomsen, Kristine Rømer; Linnet, Jakob

    2007-01-01

      The Gambling Reducing Slot Machine - Preliminary results Mette Buhl Callesen, Kristine Rømer Thomsen, Jakob Linnet and Arne Møller The PET Centre, Aarhus University Hospital and Centre of Functionally Integrative Neuroscience, Aarhus, Denmark   Slot machines are among the most addictive forms...... and willingness to continue gambling. The results may have important implications for understanding how to reduce gambling behavior in pathological gamblers.   [1] Griffiths, M. 1999. Gambling Technologies: Prospects for Problem Gambling. Journal of Gambling Studies, vol. 15(3), pp. 265-283.    ...

  1. Back pain online: a cross-sectional survey of the quality of web-based information on low back pain.

    Science.gov (United States)

    Butler, Laura; Foster, Nadine E

    2003-02-15

    A cross section of Web sites accessible to the general public was surveyed. To evaluate the quality of information on low back pain and its treatment that a "typical" patient user might access on the Internet. Individuals with back pain have a desire to learn about their condition, what to expect, and what they can do about it. Web sites play a potentially useful role in providing information to help people learn about their low back pain and select the most appropriate methods of management. A general search using popular search engines located 60 Web sites about back pain for review. A list of criteria for evaluating and scoring back pain Web sites was established using available literature and current clinical guidelines for the management of acute low back pain. The total quality score (maximum score, 38) was composed of two separate scores: one for general quality of the site (maximum score, 14) and one for site content specific to low back pain (maximum score, 24). Statistical tests, as appropriate, were used to investigate the relation between general indicators of Web site quality and total scores obtained. The quality of the Web sites surveyed was poor, most of them (n = 58, 97%) scoring less than half the maximum available score. The mean total score was 7.4 (range, 2-25). The mean score was 4.9 (range, 1-12) for general Web site quality and 2.4 (range, 1-13) for content specific to low back pain. Web sites providing references, sites created more recently, and sites not created for advertising purposes tended to be of better quality. This study highlighted the poor quality of information, particularly information about low back pain, available to "typical" patient users on the Internet. Health care professionals must have a role in evaluating existing information and in developing good-quality evidence-based Web sites. Patients with back pain should be discouraged from using the Internet as a source of information unless the Web sites they access have

  2. Radiation from a Slot System in the Coaxial Line Shield

    Science.gov (United States)

    Katrich, V. A.; Lyashchenko, V. A.; Medvedev, N. V.

    2012-06-01

    The problem of electromagnetic wave excitation, scattering and radiation by the system of transverse slots, cut in the outer conductor of an infinite coaxial line, is solved by the magnetomotive forces method. The radiation and reflection coefficients of the circular and arc slot systems are investigated in dependence on slot sizes and feeder parameters. The processes of radiation into lossy material media are studied. The researches have been carried out with the interconnection between slots of internal and external regions considered.

  3. Radio antennas

    Science.gov (United States)

    Gibson, S. W.

    This book is concerned with providing an explanation of the function of an antenna without delving too deeply into the mathematics or theory. The characteristics of an antenna are examined, taking into account aspects of antenna radiation, wave motion on the antenna, resistance in the antenna, impedance, the resonant antenna, the effect of the ground, polarization, radiation patterns, coupling effects between antenna elements, and receiving vs. transmitting. Aspects of propagation are considered along with the types of antennas, transmission lines, matching devices, questions of antenna design, antennas for the lower frequency bands, antennas for more than one band, limited space antennas, VHF antennas, and antennas for 20, 15, and 10 meters. Attention is given to devices for measuring antenna parameters, approaches for evaluating the antenna, questions of safety, and legal aspects.

  4. Metal membrane with dimer slots as a universal polarizer

    Science.gov (United States)

    Zhukovsky, Sergej; Zalkovskij, Maksim; Malureanu, Radu; Kremers, Christian; Chigrin, Dmitry; Tang, Peter T.; Jepsen, Peter U.; Lavrinenko, Andrei V.

    2014-03-01

    In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electromagnetic response of an arbitrary dimer based on the Green functions approach. The theory confirms that a great variety of polarization properties, such as birefringence, chirality and elliptical dichroism, can be achieved in a metal layer with such slot-dimer patterning (i.e. in a metasurface). Optical properties of the metasurface can be extensively tuned by varying the geometry (shape and dimensions) of the dimer, for example, by adjusting the sizes and mutual placement of the slots (e.g. inter-slot distance and alignment angle). Three basic shapes of dimers are analyzed: II-shaped (parallel slots), V-shaped, and T-shaped. These particular shapes of dimers are found to be sensitive to variations of the slots lengths and orientation of elements. Theoretical results are well supported by full-wave three-dimensional simulations. Our findings were verified experimentally on the metal membranes fabricated using UV lithography with subsequent Ni growth. Such metasurfaces were characterized using time-domain THz spectroscopy. The samples exhibit pronounced optical activity (500 degrees per wavelength) and high transmission: even though the slots cover only 4.3 % of the total membrane area the amplitude transmission reaches 0.67 at the resonance frequency 0.56 THz.

  5. Humanizing machines: Anthropomorphization of slot machines increases gambling.

    Science.gov (United States)

    Riva, Paolo; Sacchi, Simona; Brambilla, Marco

    2015-12-01

    Do people gamble more on slot machines if they think that they are playing against humanlike minds rather than mathematical algorithms? Research has shown that people have a strong cognitive tendency to imbue humanlike mental states to nonhuman entities (i.e., anthropomorphism). The present research tested whether anthropomorphizing slot machines would increase gambling. Four studies manipulated slot machine anthropomorphization and found that exposing people to an anthropomorphized description of a slot machine increased gambling behavior and reduced gambling outcomes. Such findings emerged using tasks that focused on gambling behavior (Studies 1 to 3) as well as in experimental paradigms that included gambling outcomes (Studies 2 to 4). We found that gambling outcomes decrease because participants primed with the anthropomorphic slot machine gambled more (Study 4). Furthermore, we found that high-arousal positive emotions (e.g., feeling excited) played a role in the effect of anthropomorphism on gambling behavior (Studies 3 and 4). Our research indicates that the psychological process of gambling-machine anthropomorphism can be advantageous for the gaming industry; however, this may come at great expense for gamblers' (and their families') economic resources and psychological well-being. (c) 2015 APA, all rights reserved).

  6. Broadband standard dipole antenna for antenna calibration

    Science.gov (United States)

    Koike, Kunimasa; Sugiura, Akira; Morikawa, Takao

    1995-06-01

    Antenna calibration of EMI antennas is mostly performed by the standard antenna method at an open-field test site using a specially designed dipole antenna as a reference. In order to develop broadband standard antennas, the antenna factors of shortened dipples are theoretically investigated. First, the effects of the dipole length are analyzed using the induced emf method. Then, baluns and loads are examined to determine their influence on the antenna factors. It is found that transformer-type baluns are very effective for improving the height dependence of the antenna factors. Resistive loads are also useful for flattening the frequency dependence. Based on these studies, a specification is developed for a broadband standard antenna operating in the 30 to 150 MHz frequency range.

  7. High-temperature superconducting passive microwave devices, filters and antennas

    International Nuclear Information System (INIS)

    Ohshima, S.

    2000-01-01

    High-temperature superconducting (HTS) passive microwave devices, such as filters and antennas, are promising devices. In particular, HTS filters may be successfully marketed in the near future. Cross-coupled filters, ring filters, and coplanar waveguide filters are good options to reduce filter size. On the other hand, HTS patch antennas which can be cooled by a cryo-cooler are also promising devices as well, since they show higher efficiency than normal antennas. This paper examines the design process and filter properties of HTS filters as well as the gains, directivity, and cooling system of HTS patch antennas. (author)

  8. Effect on the Tritium Breeding Ratio due to a distributed ICRF antenna in a DEMO reactor

    International Nuclear Information System (INIS)

    Garcia, A.; Noterdaeme, J.-M.; Fischer, U.; Dies, J.

    2016-01-01

    This thesis reports results of MCNP-5 calculations, with the nuclear data library FENDL-2.1, to assess the effect on the Tritium Breeding Ratio (TBR) due to a distributed Ion Cyclotron Range of Frequencies (ICRF) antenna integrated in the blanket of a DEMO fusion power reactor. A preliminary design of the antenna with a reference configuration of the DEMO reactor was used together with a parametric analysis for different parameters that strongly affect the TBR. These are the type of breeding blanket (Helium Cooled Pebble Bed, Helium Cooled Lithium Lead and Water Cooled Lithium Lead), the covering ratio of the straps of the antenna (the ratio between the surface of all the straps and the projected surface of the antenna slot: 0.49, 0.72 and 0.94), the antenna radial thickness (20 cm and 40 cm), the thickness of the straps (2 cm, 4 cm and a double layer of 0.2 cm plus 2.5 cm with the composition of the First Wall), and finally the poloidal position of the antenna (0°, which is the equatorial port, 40° and 90°, which is the upper port). For an antenna with a full toroidal circumference of 360°, located poloidaly at 40° with a poloidal extension of 1 m and a total First Wall surface of 67 m"2, the reduction of the TBR is −0.35% for a HCPB blanket concept, −0.53% for a HCLL blanket concept and −0.51% for a WCLL blanket concept. In all cases covered by the parametric analysis, the loss of TBR remains below 0.61%. Such a distributed ICRF antenna has thus only a marginal effect on the TBR for a DEMO reactor.

  9. Effect on the Tritium Breeding Ratio due to a distributed ICRF antenna in a DEMO reactor

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, A., E-mail: albert.garcia.hp@gmail.com [Max-Planck-Institut für Plasmaphysik (IPP), Garching (Germany); Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Polytechnic University of Catalonia (UPC), Barcelona (Spain); Department of Applied Physics, Ghent University, Ghent (Belgium); Noterdaeme, J.-M. [Max-Planck-Institut für Plasmaphysik (IPP), Garching (Germany); Department of Applied Physics, Ghent University, Ghent (Belgium); Fischer, U. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Dies, J. [Polytechnic University of Catalonia (UPC), Barcelona (Spain)

    2016-11-15

    This thesis reports results of MCNP-5 calculations, with the nuclear data library FENDL-2.1, to assess the effect on the Tritium Breeding Ratio (TBR) due to a distributed Ion Cyclotron Range of Frequencies (ICRF) antenna integrated in the blanket of a DEMO fusion power reactor. A preliminary design of the antenna with a reference configuration of the DEMO reactor was used together with a parametric analysis for different parameters that strongly affect the TBR. These are the type of breeding blanket (Helium Cooled Pebble Bed, Helium Cooled Lithium Lead and Water Cooled Lithium Lead), the covering ratio of the straps of the antenna (the ratio between the surface of all the straps and the projected surface of the antenna slot: 0.49, 0.72 and 0.94), the antenna radial thickness (20 cm and 40 cm), the thickness of the straps (2 cm, 4 cm and a double layer of 0.2 cm plus 2.5 cm with the composition of the First Wall), and finally the poloidal position of the antenna (0°, which is the equatorial port, 40° and 90°, which is the upper port). For an antenna with a full toroidal circumference of 360°, located poloidaly at 40° with a poloidal extension of 1 m and a total First Wall surface of 67 m{sup 2}, the reduction of the TBR is −0.35% for a HCPB blanket concept, −0.53% for a HCLL blanket concept and −0.51% for a WCLL blanket concept. In all cases covered by the parametric analysis, the loss of TBR remains below 0.61%. Such a distributed ICRF antenna has thus only a marginal effect on the TBR for a DEMO reactor.

  10. Effects of geometry on slot-jet film cooling performance

    Energy Technology Data Exchange (ETDEWEB)

    Hyams, D.G.; McGovern, K.T.; Leylek, J.H. [Clemson Univ., SC (United States)

    1995-10-01

    The physics of the film cooling process for shaped, inclined slot-jets with realistic slot-length-to-width ratios (L/s) is studied for a range of blowing ratio (M) and density ratio (DR) parameters typical of gas turbine operations. For the first time in the open literature, the effect of inlet and exit shaping of the slot-jet on both flow and thermal field characteristics is isolated, and the dominant mechanisms responsible for differences in these characteristics are documented. A previously documented computational methodology was applied for the study of four distinct configurations: (1) slot with straight edges and sharp corners (reference case); (2) slot with shaped inlet region; (3) slot with shaped exit region; and (4) slot with both shaped inlet and exit regions. Detailed field results as well as surface phenomena involving adiabatic film effectiveness ({eta}) and heat transfer coefficient (h) are presented. It is demonstrated that both {eta} and h results are vital in the proper assessment of film cooling performance. All simulations were carried out using a multi-block, unstructured/adaptive grid, fully explicit, time-marching solver with multi-grid, local time stepping, and residual smoothing type acceleration techniques. Special attention was paid to and full documentation provided for: (1) proper modeling of the physical phenomena; (2) exact geometry and high quality grid generation techniques; (3) discretization schemes; and (4) turbulence modeling issues. The key parameters M and DR were varied from 1.0 to 2.0 and 1.5 to 2.0, respectively, to show their influence. Simulations were repeated for slot length-to-width ratio (L/s) of 3.0 and 4.5 in order to explain the effects of this important parameter. Additionally, the performance of two popular turbulence models, standard k-F, and RNG k-E, were studied to establish their ability to handle highly elliptic jet/crossflow interaction type processes.

  11. Simulating the JET ITER-like Antenna circuit

    International Nuclear Information System (INIS)

    Van Eester, D.; Lerche, E.; Durodie, F.; Evrard, M.; Huygen, S.; Ongena, J.; Vrancken, M.; Argouarch, A.; Blackman, T.; Jacquet, P.; Mayoral, M.-L.; Monakhov, I.; Nightingale, M.; Wooldridge, E.; Whitehurst, A.; Goulding, R. H.

    2009-01-01

    A set of simulation/interpretation tools based on transmission line theory and on the RF model developed by M. Vrancken has been developed to study the ITER-like Antenna (ILA) at JET. For given tuning element settings, the unique solution of the equations governing the ILA circuit requires solving a system of coupled linear equations relating the voltages and currents at the antenna straps and other key locations. This computation allows cross-checking predicted values against measured experimental ones. Further more, a minimization procedure allows improving the correspondence with the quantities measured in the circuit during shots, thus coping with unavoidable errors arising from uncertainties in the measurements or from inaccuracies in the adopted RF model. Typical applications are e.g. fine-tuning of the second-stage of the ILA circuit for increased ELM-resilience, cross-checking the calibration of the measurements throughout the circuit and predicting the antenna performance and matching conditions in new plasma scenarios.

  12. Flexural and Thermal Properties of Novel Energy Conservation Slotted Reinforced Concrete Beams

    Directory of Open Access Journals (Sweden)

    Gao Ma

    2016-01-01

    Full Text Available Conventional solid reinforced concrete (RC beams were modified to slotted beams for consideration as thermal insulation structural components. The slotted beam consisted of an outer and an inner beam, respectively, with a slot located near the middle of the beam along its width direction for filling thermal insulation material. Flexural and thermal behavior of the slotted beams were investigated. Three RC reference solid beams and six slotted beams were fabricated and tested under four-point bending tests. The test results indicated that the failure mode of both slotted beams and the solid beams was flexural failure. However, the damage process of the slotted beams was different from that of the solid beams at the final loading stage. The moment curvature analysis indicated that the tensile reinforcement ratio of the outer and inner beams had an important effect on the flexural behavior, especially the ductility of the slotted beams. Thermal study indicated that the heat transfer coefficient of the slotted beam was greatly reduced and the thermal inertia factor increased a lot, compared with the solid beam. In addition, FE simulation results showed that a new frame structure using slotted beams exhibited obvious and attractive thermal insulation property.

  13. Low back pain tied to spinal endometriosis.

    Science.gov (United States)

    Dongxu, Zhao; Fei, Yin; Xing, Xiao; Bo-Yin, Zhang; Qingsan, Zhu

    2014-05-01

    Case report. We present a case of endometriosis of lumbar vertebrae. The literatures are reviewed with endometriosis of spine. Endometriosis is a common condition, which is defined as endometrial tissue lying outside the endometrial cavity. It is usually found within the peritoneal cavity, predominantly within the pelvis, commonly on the uterosacral ligaments. It can also be found in other sites such as umbilicus, abdominal scars, nasal passages and pleural cavity. But it is very rarely seen in the spine, with no report of endometriosis found in the lumbar vertebrae. A 33-year-old woman presented with severe low back pain. She had the low back pain periodically for 3 years, and the pain was associated with menstruation. Radiographs showed a lesion in the posterior L3 body. After surgery, tissue biopsy indicated the presence of endometrial tissue in the lesion and thus confirmed endometriosis. Most cases of spine endometriosis that have been reported are usually found inside spinal canal, endorachis or spinal cord. But spinal vertebrae can also be involved in endometriosis. Although endometriosis is a rare possible cause of periodical low back pain in women of childbearing age, we suggest that if a woman suffering from periodical low back pain is encountered, do not ignore the possibility of endometriosis in the spine.

  14. Mixed Element Formulation for the Finite Element-Boundary Integral Method

    National Research Council Canada - National Science Library

    Meese, J; Kempel, L. C; Schneider, S. W

    2006-01-01

    A mixed element approach using right hexahedral elements and right prism elements for the finite element-boundary integral method is presented and discussed for the study of planar cavity-backed antennas...

  15. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

    Directory of Open Access Journals (Sweden)

    Md. Moinul Islam

    2015-01-01

    Full Text Available A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR and capacitance-loaded strip (CLS unit cells is presented for Ultra wideband (UWB microwave imaging applications. Four left-handed (LH metamaterial (MTM unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR with a capacitance-loaded strip (CLS to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

  16. Fractal apertures in waveguides, conducting screens and cavities analysis and design

    CERN Document Server

    Ghosh, Basudeb; Kartikeyan, M V

    2014-01-01

    This book deals with the design and analysis of fractal apertures in waveguides, conducting screens and cavities using numerical electromagnetics and field-solvers. The aim is to obtain design solutions with improved accuracy for a wide range of applications. To achieve this goal, a few diverse problems are considered. The book is organized with adequate space dedicated for the design and analysis of fractal apertures in waveguides, conducting screens, and cavities, microwave/millimeter wave applications followed by detailed case-study problems to infuse better insight and understanding of the subject. Finally, summaries and suggestions are given for future work. Fractal geometries were widely used in electromagnetics, specifically for antennas and frequency selective surfaces (FSS). The self-similarity of fractal geometry gives rise to a multiband response, whereas the  space-filling nature of the fractal geometries makes it an efficient element in antenna and FSS unit cell miniaturization. Until now, no e...

  17. Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Checchin, Mattia [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Grassellino, Anna [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Martinello, Martina [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Posen, Sam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Romanenko, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Zasadzinski, John [Illinois Inst. of Technology, Chicago, IL (United States)

    2016-06-01

    The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q0 at high gradients.

  18. Slot-type kicker for the AA stochastic cooling

    CERN Multimedia

    Photographic Service

    1979-01-01

    A "slotted transmission line" structure was used for both pickups and the kicker of one of the stochastic cooling systems of the Antiproton Accumulator (AA). They served for the cooling of the high-density stack, in momentum and in both transverse planes. In the beginning in a single band, 1-2 GHz, later in 3 bands, 1-2, 2-4 and 4-8 GHz. The kicker of the first generation, shown here, was located where the dispersion was zero and the beam size small, and thus had a quadratic cross-section. The pickups were rectangular and wider in the horizontal plane. See also 7906193

  19. Frequency selective surfaces based high performance microstrip antenna

    CERN Document Server

    Narayan, Shiv; Jha, Rakesh Mohan

    2016-01-01

    This book focuses on performance enhancement of printed antennas using frequency selective surfaces (FSS) technology. The growing demand of stealth technology in strategic areas requires high-performance low-RCS (radar cross section) antennas. Such requirements may be accomplished by incorporating FSS into the antenna structure either in its ground plane or as the superstrate, due to the filter characteristics of FSS structure. In view of this, a novel approach based on FSS technology is presented in this book to enhance the performance of printed antennas including out-of-band structural RCS reduction. In this endeavor, the EM design of microstrip patch antennas (MPA) loaded with FSS-based (i) high impedance surface (HIS) ground plane, and (ii) the superstrates are discussed in detail. The EM analysis of proposed FSS-based antenna structures have been carried out using transmission line analogy, in combination with the reciprocity theorem. Further, various types of novel FSS structures are considered in desi...

  20. Interaction of IREB with a cavity

    International Nuclear Information System (INIS)

    Sawhney, R.; Mishra, Mamta; Purkayastha, A.D.; Rambabu, P.; Maheshwari, K.P.

    1991-01-01

    The propagation of an intense pulsed relativistic electron beam (IREB) through a cavity resonator is considered. The cavity gets shock excited. The electromagnetic fields so generated interact with the beam in such a way that the energy is transferred from the front of the beam to the back. As a result the beams gets energized but shortened in time. Analysis for the chosen dominant mode of the cavity viz. TMsub(010) is carried out. The induced electric field excited is calculated and the accelerating potential is estimated. The results are compared with the recent-experiments. (author). 5 refs., 1 fig

  1. A Compact Annular Ring Microstrip Antenna for WSN Applications

    Directory of Open Access Journals (Sweden)

    Daihua Wang

    2012-06-01

    Full Text Available A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna’s performance of a steel installation base. By using a chip resistor of large resistance (120 Ω the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and –2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

  2. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed...

  3. A reciprocity formulation for the EM scattering by an obstacle within a large open cavity

    Science.gov (United States)

    Pathak, Prabhakar H.; Burkholder, Robert J.

    1993-01-01

    A formulation based on a generalized reciprocity theorem is developed for analyzing the external high frequency EM scattering by a complex obstacle inside a relatively arbitrary open-ended waveguide cavity when it is illuminated by an external source. This formulation is also extended to include EM fields whose time dependence may be nonperiodic. A significant advantage of this formulation is that it allows one to break up the analysis into two independent parts; one deals with the waveguide cavity shape alone and the other with the obstacle alone. The external scattered field produced by the obstacle (in the presence of the waveguide cavity structure) is given in terms of a generalized reciprocity integral over a surface S(T) corresponding to the interior waveguide cavity cross section located conveniently but sufficiently close to the obstacle. Furthermore, the fields coupled into the cavity from the source in the exterior region generally need to propagate only one-way via the open front end (which is directly illuminated) to the interior surface S(T) in this approach, and not back, in order to find the external field scattered by the obstacle.

  4. Measure of back angle cross sections of antiproton-nucleus elastic scattering at 48 and 180 MeV

    International Nuclear Information System (INIS)

    Berrada, M.

    1986-04-01

    Antiproton-nucleus elastic scattering was studied in the LEAR ring at CERN. The scattering cross section at back angles (θ LAB = 142 to 164 deg inclusive) was measured using plastic scintillation detectors. Analysis of experimental data at 47 MeV for a CH target and at 182 MeV for CH, C12, 016, and 018 targets produces differential cross sections for back angles less than or equal to a few dozen microbarns. These results agree with theoretical microscopic predictions. The analysis improves understanding of antiproton-nucleus interaction and introduces a constraint on the construction of optical potentials. The antiproton-nucleus potential is shown to be highly absorbing, thereby excluding S type potentials, and removing the ambiguity arising from the analysis of antiprotonic atoms. The results also show that there is no attractive pocket in the real potential likely to lead to an increase of the back angle cross sections [fr

  5. Ion cyclotron modes in a low density plasma cavity. Part I: Theory

    International Nuclear Information System (INIS)

    Sawley, M.L.

    1990-12-01

    Ion cyclotron modes excited in a low density, cylindrical plasma cavity using an external inductive antenna are investigated theoretically. These modes, which have a long parallel wavelength, exhibit a strong electrostatic character and are only weakly coupled to the antenna fields. It is shown that, despite the low frequency considered, electron dynamics play a dominant role via the effects of both Landau damping and electron inertia. The characteristics of the wavefields associated with these modes, relevant to an experimental investigation, are described. (author) 8 figs., 1 tab., 10 refs

  6. Wideband or Dual-Band Low-Profile Circular Patch Antenna with High Gain and Sidelobe Suppression

    DEFF Research Database (Denmark)

    Squadrito, Paolo; Zhang, Shuai; Pedersen, Gert F.

    2018-01-01

    This paper presents a wideband or dual-band circular disk antenna with high gain and sidelobe suppression (SLS). The antenna has a single layer and single-fed configuration. The antenna can operate with the radiation field superposition of TM12 and TM14 modes at one frequency, which provides high...... gain and SLS. A circle of 10 shorting vias with non-identical diameters are loaded inside the antenna cavity in order to excite the field superposition of TM11 and TM13 modes at another frequency. By modifying the radius of the vias, the resonant frequency with the TM11 and TM13 superposition can...... be tuned closer to or further away from the one with the TM12 and TM14 superposition. In this way, a wideband or dual-band behavior can be obtained with high gain and SLS. The proposed antenna achieves the impedance bandwidth of 6.46% for the wideband case, which is over 6 times wider than the previous...

  7. Cross-sectional survey of attitudes and beliefs about back pain in New Zealand

    Science.gov (United States)

    Darlow, Ben; Perry, Meredith; Stanley, James; Mathieson, Fiona; Melloh, Markus; Baxter, G David; Dowell, Anthony

    2014-01-01

    Objectives To explore the prevalence of attitudes and beliefs about back pain in New Zealand and compare certain beliefs based on back pain history or health professional exposure. Design Population-based cross-sectional survey. Setting Postal survey. Participants New Zealand residents and citizens aged 18 years and above. 1000 participants were randomly selected from the New Zealand Electoral Roll. Participants listed on the Electoral Roll with an overseas postal address were excluded. 602 valid responses were received. Measures Attitudes and beliefs about back pain were measured with the Back Pain Attitudes Questionnaire (Back-PAQ). The interaction between attitudes and beliefs and (1) back pain experience and (2) health professional exposure was investigated. Results The lifetime prevalence of back pain was reported as 87% (95% CI 84% to 90%), and the point prevalence as 27% (95% CI 24% to 31%). Negative views about the back and back pain were prevalent, in particular the need to protect the back to prevent injury. People with current back pain had more negative overall scores, particularly related to back pain prognosis. There was uncertainty about links between pain and injury and appropriate physical activity levels during an episode of back pain. Respondents had more positive views about activity if they had consulted a health professional about back pain. The beliefs of New Zealanders appeared to be broadly similar to those of other Western populations. Conclusions A large proportion of respondents believed that they needed to protect their back to prevent injury; we theorise that this belief may result in reduced confidence to use the back and contribute to fear avoidance. Uncertainty regarding what is a safe level of activity during an episode of back pain may limit participation. People experiencing back pain may benefit from more targeted information about the positive prognosis. The provision of clear guidance about levels of activity may enable

  8. Multiplexed Simultaneous High Sensitivity Sensors with High-Order Mode Based on the Integration of Photonic Crystal 1 × 3 Beam Splitter and Three Different Single-Slot PCNCs.

    Science.gov (United States)

    Zhou, Jian; Huang, Lijun; Fu, Zhongyuan; Sun, Fujun; Tian, Huiping

    2016-07-07

    We simulated an efficient method for the sensor array of high-sensitivity single-slot photonic crystal nanobeam cavities (PCNCs) on a silicon platform. With the combination of a well-designed photonic crystal waveguide (PhCW) filter and an elaborate single-slot PCNC, a specific high-order resonant mode was filtered for sensing. A 1 × 3 beam splitter carefully established was implemented to split channels and integrate three sensors to realize microarrays. By applying the three-dimensional finite-difference-time-domain (3D-FDTD) method, the sensitivities calculated were S₁ = 492 nm/RIU, S₂ = 244 nm/RIU, and S₃ = 552 nm/RIU, respectively. To the best of our knowledge, this is the first multiplexing design in which each sensor cite features such a high sensitivity simultaneously.

  9. Reduction of the In-Band RCS of Microstrip Patch Antenna by Using Offset Feeding Technique

    Directory of Open Access Journals (Sweden)

    Weiwei Xu

    2014-01-01

    Full Text Available This paper presents a method for implementing a low in-band scattering design for microstrip patch antennas based on the analysis of structural mode scattering and radiation characteristics. The antenna structure is first designed to have the lowest structural mode scattering in a desired frequency band. The operating frequency band of the antenna is then changed to coincide with that of the lowest structural mode scattering by adjusting the feed position on the antenna (offset feeding to achieve an antenna with low in-band radar cross section (RCS. In order to reduce the level of cross polarization of the antenna caused by offset feeding, symmetry feeding structures for both single patch antennas and two-patch arrays are proposed. Examples that show the efficiency of the method are given, and the results illustrate that the in-band RCS of the proposed antennas can be reduced by as much as 17 dBsm for plane waves impinging from the normal direction compared to patch antennas fed by conventional methods.

  10. Micromachined On-Chip Dielectric Resonator Antenna Operating at 60 GHz

    KAUST Repository

    Sallam, Mai

    2015-06-01

    This paper presents a novel cylindrical Dielectric Resonator Antenna (DRA) suitable for millimeter-wave on-chip systems. The antenna was fabricated from a single high resistivity silicon wafer via micromachining technology. The new antenna was characterized using HFSS and experimentally with good agreement been found between the simulations and experiment. The proposed DRA has good radiation characteristics, where its gain and radiation efficiency are 7 dBi and 79.35%, respectively. These properties are reasonably constant over the working frequency bandwidth of the antenna. The return loss bandwidth was 2.23 GHz, which corresponds to 3.78% around 60 GHz. The antenna was primarily a broadside radiator with -15 dB cross polarization level.

  11. A self-biased 3D tunable helical antenna in ferrite LTCC substrate

    KAUST Repository

    Ghaffar, Farhan A.; Shamim, Atif

    2015-01-01

    A ferrite LTCC based helical antenna which also provides magneto-static bias for its frequency tuning is presented in this work. The 3D helical-cum-bias winding design avoids the use of large external electromagnets which are traditionally used with ferrite based tunable antennas. This reduces the overall size of the design while making it efficient by getting rid of demagnetization effect experienced at the air-to-ferrite interface. RF choke and DC blocking capacitor, required to isolate the RF and DC passing through a single structure, are integrated within the multi-layer Ferrite LTCC substrate. Magnetostatic and microwave simulations have been carried out for the design optimization. The prototype antenna demonstrates a tuning range of 10 % around 13 GHz. An optimized design with an air cavity is also presented which reduces the biasing power requirement by 40 %.

  12. A self-biased 3D tunable helical antenna in ferrite LTCC substrate

    KAUST Repository

    Ghaffar, Farhan A.

    2015-07-19

    A ferrite LTCC based helical antenna which also provides magneto-static bias for its frequency tuning is presented in this work. The 3D helical-cum-bias winding design avoids the use of large external electromagnets which are traditionally used with ferrite based tunable antennas. This reduces the overall size of the design while making it efficient by getting rid of demagnetization effect experienced at the air-to-ferrite interface. RF choke and DC blocking capacitor, required to isolate the RF and DC passing through a single structure, are integrated within the multi-layer Ferrite LTCC substrate. Magnetostatic and microwave simulations have been carried out for the design optimization. The prototype antenna demonstrates a tuning range of 10 % around 13 GHz. An optimized design with an air cavity is also presented which reduces the biasing power requirement by 40 %.

  13. Ring cavity for a Raman capillary waveguide amplifier

    Science.gov (United States)

    Kurnit, N.A.

    1981-01-27

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  14. Ring cavity for a Raman capillary waveguide amplifir

    Science.gov (United States)

    Kurnit, N.A.

    1981-01-27

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  15. Gain Enhancement of a Microstrip Patch Antenna Using a Reflecting Layer

    Directory of Open Access Journals (Sweden)

    Anwer Sabah Mekki

    2015-01-01

    Full Text Available A low profile, unidirectional, dual layer, and narrow bandwidth microstrip patch antenna is designed to resonate at 2.45 GHz. The proposed antenna is suitable for specific applications, such as security and military systems, which require a narrow bandwidth and a small antenna size. This work is mainly focused on increasing the gain as well as reducing the size of the unidirectional patch antenna. The proposed antenna is simulated and measured. According to the simulated and measured results, it is shown that the unidirectional antenna has a higher gain and a higher front to back ratio (F/B than the bidirectional one. This is achieved by using a second flame retardant layer (FR-4, coated with an annealed copper of 0.035 mm at both sides, with an air gap of 0.04λ0 as a reflector. A gain of 5.2 dB with directivity of 7.6 dBi, F/B of 9.5 dB, and −18 dB return losses (S11 are achieved through the use of a dual substrate layer of FR-4 with a relative permittivity of 4.3 and a thickness of 1.6 mm. The proposed dual layer microstrip patch antenna has an impedance bandwidth of 2% and the designed antenna shows very low complexity during fabrication.

  16. A method for detecting fungal contaminants in wall cavities.

    Science.gov (United States)

    Spurgeon, Joe C

    2003-01-01

    This article describes a practical method for detecting the presence of both fungal spores and culturable fungi in wall cavities. Culturable fungi were collected in 25 mm cassettes containing 0.8 microm mixed cellulose ester filters using aggressive sampling conditions. Both culturable fungi and fungal spores were collected in modified slotted-disk cassettes. The sample volume was 4 L. The filters were examined microscopically and dilution plated onto multiple culture media. Collecting airborne samples in filter cassettes was an effective method for assessing wall cavities for fungal contaminants, especially because this method allowed the sample to be analyzed by both microscopy and culture media. Assessment criteria were developed that allowed the sample results to be used to classify wall cavities as either uncontaminated or contaminated. As a criterion, wall cavities with concentrations of culturable fungi below the limit of detection (LOD) were classified as uncontaminated, whereas those cavities with detectable concentrations of culturable fungi were classified as contaminated. A total of 150 wall cavities was sampled as part of a field project. The concentrations of culturable fungi were below the LOD in 34% of the samples, whereas Aspergillus and/or Penicillium were the only fungal genera detected in 69% of the samples in which culturable fungi were detected. Spore counting resulted in the detection of Stachybotrys-like spores in 25% of the samples that were analyzed, whereas Stachybotrys chartarum colonies were only detected on 2% of malt extract agar plates and on 6% of corn meal agar plates.

  17. Clear air boundary layer spaced antenna wind measurement with the Multiple Antenna Profiler (MAPR

    Directory of Open Access Journals (Sweden)

    S. A. Cohn

    Full Text Available Spaced antenna (SA wind measurement techniques are applied to Multiple Antenna Profiler (MAPR data to evaluate its performance in clear air conditions. MAPR is a multiple antenna 915 MHz wind profiler developed at the National Center for Atmospheric Research (NCAR and described in Cohn et al. (1997, designed to make high resolution wind measurements. Previous reported measurements with MAPR were restricted to precipitation because of low signal to noise (SNR and signal to ground-clutter (SCR ratios. By using a standard pulse-coding technique and upgrading the profiler control software, increases in average power and SNR were achieved, making routine measurements in clear air possible. Comparison of winds measured by MAPR and by a sonic anemometer on a nearby 300 m tower show correlation coefficients in the range of R2 = 0.75 – 0.80, and an average absolute error of ~ 1.4 m s - 1 . This compares favorably with the agreement typically found in wind profiler comparisons. We also consider the use of the parameter ah , which is related to the value of the cross-correlation function at its zero crossing. This parameter is a data quality indicator and possibly a key component in a ground clutter removal technique.

    Key words. Meteorology and atmospheric dynamics (mesoscale meteorology; instruments and techniques – Radio science (remote sensing

  18. Towards strong light-matter coupling at the single-resonator level with sub-wavelength mid-infrared nano-antennas

    Energy Technology Data Exchange (ETDEWEB)

    Malerba, M.; De Angelis, F., E-mail: francesco.deangelis@iit.it [Istituto Italiano di Tecnologia, Via Morego, 30, I-16163 Genova (Italy); Ongarello, T.; Paulillo, B.; Manceau, J.-M.; Beaudoin, G.; Sagnes, I.; Colombelli, R., E-mail: raffaele.colombelli@u-psud.fr [Centre for Nanoscience and Nanotechnology (C2N Orsay), CNRS UMR9001, Univ. Paris Sud, Univ. Paris Saclay, 91405 Orsay (France)

    2016-07-11

    We report a crucial step towards single-object cavity electrodynamics in the mid-infrared spectral range using resonators that borrow functionalities from antennas. Room-temperature strong light-matter coupling is demonstrated in the mid-infrared between an intersubband transition and an extremely reduced number of sub-wavelength resonators. By exploiting 3D plasmonic nano-antennas featuring an out-of-plane geometry, we observed strong light-matter coupling in a very low number of resonators: only 16, more than 100 times better than what reported to date in this spectral range. The modal volume addressed by each nano-antenna is sub-wavelength-sized and it encompasses only ≈4400 electrons.

  19. Mechanism Design for Multi-slot Ads Auction in Sponsored Search Markets

    Science.gov (United States)

    Deng, Xiaotie; Sun, Yang; Yin, Ming; Zhou, Yunhong

    In this paper, we study pricing models for multi-slot advertisements, where advertisers can bid to place links to their sales webpages at one or multiple slots on a webpage, called the multi-slot AD auction problem. We develop and analyze several important mechanisms, including the VCG mechanism for multi-slot ads auction, the optimal social welfare solution, as well as two weighted GSP-like protocols (mixed and hybrid). Furthermore, we consider that forward-looking Nash equilibrium and prove its existence in the weighted GSP-like pricing protocols.

  20. Highly miniaturised semi-loop meandered dual-band MIMO antenna system

    KAUST Repository

    Jehangir, Syed S.

    2017-12-05

    A novel dual-band two-element directional multiple-input-multiple-output (MIMO) antenna system is presented with 68% miniaturisation, which is achieved using a semi-loop meandered driven element and a small ground plane. The centre frequency of operation is 2 GHz. The antenna system covers two bands: the telemetry L-band 1.27-1.43 GHz and the global system for mobile communications/long-term evolution band 1.8-2.133 GHz. The simulation and measurement results are in good agreement. The proposed antenna system mimics the quasi-Yagi antenna configuration with a measured front-to-back ratio of around 15 dB at 1.35 GHz and 17 dB at 2 GHz, which is achieved without using a large ground plane, extra metallic structures, multiple reflector elements, or any complex technique. A gain of more than 5 dBi is measured for the single element with a total radiation efficiency of around 85% in both bands. The measured isolation of the proposed MIMO antenna is more than 15 dB with < 0.0785 measured envelope correlation coefficient values in both bands.

  1. Highly miniaturised semi-loop meandered dual-band MIMO antenna system

    KAUST Repository

    Jehangir, Syed S.; Sharawi, Mohammad S.; Shamim, Atif

    2017-01-01

    A novel dual-band two-element directional multiple-input-multiple-output (MIMO) antenna system is presented with 68% miniaturisation, which is achieved using a semi-loop meandered driven element and a small ground plane. The centre frequency of operation is 2 GHz. The antenna system covers two bands: the telemetry L-band 1.27-1.43 GHz and the global system for mobile communications/long-term evolution band 1.8-2.133 GHz. The simulation and measurement results are in good agreement. The proposed antenna system mimics the quasi-Yagi antenna configuration with a measured front-to-back ratio of around 15 dB at 1.35 GHz and 17 dB at 2 GHz, which is achieved without using a large ground plane, extra metallic structures, multiple reflector elements, or any complex technique. A gain of more than 5 dBi is measured for the single element with a total radiation efficiency of around 85% in both bands. The measured isolation of the proposed MIMO antenna is more than 15 dB with < 0.0785 measured envelope correlation coefficient values in both bands.

  2. On-Chip Implantable Antennas for Wireless Power and Data Transfer in a Glaucoma-Monitoring SoC

    KAUST Repository

    Marnat, Loic

    2013-04-17

    For the first time separate transmit and receive onchip antennas have been designed in a eye environment for implantable intraocular pressure monitoring application. The miniaturized antennas fit on a 1.4 mm3 CMOS (0.18 μm) chip with the rest of the circuitry. A 5.2 GHz novel inductive fed and loaded receive monopole antenna is used for wireless powering the chip and is conjugately matched to the rectifier in the energy harvesting and storage unit. The 2.4 GHz transmit antenna is an octagonal loop which also acts as the inductor of the voltage control oscillator resonant tank. To emulate the eye environment in measurements, a custom test setup is developed which comprises plexiglass cavities filled with saline solution. A transition, employing a balun, is also designed which transforms the differential impedance of on-chip antennas immersed in saline solution to a 50 ! single-ended micrsotrip line. The antennas on a lossy Si substrate and eye environment provide sufficient gain to establish wireless communication with an external reader placed few cm away from the eye.

  3. Reconfigurable micromachined antenna with polarization diversity for mm-wave applications

    KAUST Repository

    Sallam, Mai O.

    2012-03-01

    In this paper a novel MEMS antenna with reconfigurable polarization operating at 60 GHz is presented. This antenna can provide vertical linear polarization, horizontal linear polarization, left hand circular polarization (LHCP), or right hand circular polarization (RHCP) based on the states of the switches present in the feeding network. The proposed antenna is characterized by having its radiating elements isolated from the feeding circuitry via a ground plane without the need for wafer bonding or hybrid integration. Such advantage results in good electric performance while maintains low fabrication cost. The antenna parameters are optimized using HFSS and the results are cross-validated using CST. The good agreement between the two simulators, confirms that the proposed antenna enjoys attractive radiation characteristics for all polarization senses. © 2012 IEEE.

  4. Reconfigurable micromachined antenna with polarization diversity for mm-wave applications

    KAUST Repository

    Sallam, Mai O.; Soliman, Ezzeldin A.; Sedky, Sherif

    2012-01-01

    In this paper a novel MEMS antenna with reconfigurable polarization operating at 60 GHz is presented. This antenna can provide vertical linear polarization, horizontal linear polarization, left hand circular polarization (LHCP), or right hand circular polarization (RHCP) based on the states of the switches present in the feeding network. The proposed antenna is characterized by having its radiating elements isolated from the feeding circuitry via a ground plane without the need for wafer bonding or hybrid integration. Such advantage results in good electric performance while maintains low fabrication cost. The antenna parameters are optimized using HFSS and the results are cross-validated using CST. The good agreement between the two simulators, confirms that the proposed antenna enjoys attractive radiation characteristics for all polarization senses. © 2012 IEEE.

  5. Slotted Blades Savonius Wind Turbine Analysis by CFD

    Directory of Open Access Journals (Sweden)

    Andrea Alaimo

    2013-12-01

    Full Text Available In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting characteristic of the proposed Savonius wind generator configuration.

  6. Design of a compact and integrated TM-rotated/TE-through polarization beam splitter for silicon-based slot waveguides.

    Science.gov (United States)

    Xu, Yin; Xiao, Jinbiao

    2016-01-20

    A compact and integrated TM-rotated/TE-through polarization beam splitter for silicon-based slot waveguides is proposed and characterized. For the input TM mode, it is first transferred into the cross strip waveguide using a tapered directional coupler (DC), and then efficiently rotated to the corresponding TE mode using an L-shaped bending polarization rotator (PR). Finally, the TE mode for slot waveguide at the output end is obtained with the help of a strip-to-slot mode converter. By contrast, for the input TE mode, it almost passes through the slot waveguide directly and outputs at the bar end with nearly neglected coupling due to a large mode mismatch. Moreover, an additional S-bend connecting the tapered DC and bending PR is used to enhance the performance. Results show that a total device length of 19.6 μm is achieved, where the crosstalk (CT) and polarization conversion loss are, respectively -26.09 and 0.54 dB, for the TM mode, and the CT and insertion loss are, respectively, -22.21 and 0.41 dB, for the TE mode, both at 1.55 μm. The optical bandwidth is approximately 50 nm with a CT<-20  dB. In addition, fabrication tolerances and field evolution are also presented.

  7. Scheme for the implementation of a universal quantum cloning machine via cavity-assisted atomic collisions in cavity QED

    International Nuclear Information System (INIS)

    Zou Xubo; Pahlke, K.; Mathis, W.

    2003-01-01

    We propose a scheme to implement the 1→2 universal quantum cloning machine of Buzek and Hillery [Phys. Rev. A 54, 1844 (1996)] in the context of cavity QED. The scheme requires cavity-assisted collision processes between atoms, which cross through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited to face the decoherence problem. That's why the requirements on the cavity quality factor can be loosened

  8. Broadband Monopole Antenna

    Science.gov (United States)

    2017-09-14

    December 2017 The below identified patent application is available for licensing. Requests for information should be addressed to...CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0002] United States Patent Application Ser. No. 15/220,692 filed on July 27, 2016 is incorporated by...antenna operating near 2.5 GHz to obtain an octave of bandwidth. One solution for this is given by Werner et al. in United States Patent

  9. Discrete-Slots Models of Visual Working-Memory Response Times

    Science.gov (United States)

    Donkin, Christopher; Nosofsky, Robert M.; Gold, Jason M.; Shiffrin, Richard M.

    2014-01-01

    Much recent research has aimed to establish whether visual working memory (WM) is better characterized by a limited number of discrete all-or-none slots or by a continuous sharing of memory resources. To date, however, researchers have not considered the response-time (RT) predictions of discrete-slots versus shared-resources models. To complement the past research in this field, we formalize a family of mixed-state, discrete-slots models for explaining choice and RTs in tasks of visual WM change detection. In the tasks under investigation, a small set of visual items is presented, followed by a test item in 1 of the studied positions for which a change judgment must be made. According to the models, if the studied item in that position is retained in 1 of the discrete slots, then a memory-based evidence-accumulation process determines the choice and the RT; if the studied item in that position is missing, then a guessing-based accumulation process operates. Observed RT distributions are therefore theorized to arise as probabilistic mixtures of the memory-based and guessing distributions. We formalize an analogous set of continuous shared-resources models. The model classes are tested on individual subjects with both qualitative contrasts and quantitative fits to RT-distribution data. The discrete-slots models provide much better qualitative and quantitative accounts of the RT and choice data than do the shared-resources models, although there is some evidence for “slots plus resources” when memory set size is very small. PMID:24015956

  10. Multiplexed Simultaneous High Sensitivity Sensors with High-Order Mode Based on the Integration of Photonic Crystal 1 × 3 Beam Splitter and Three Different Single-Slot PCNCs

    Directory of Open Access Journals (Sweden)

    Jian Zhou

    2016-07-01

    Full Text Available We simulated an efficient method for the sensor array of high-sensitivity single-slot photonic crystal nanobeam cavities (PCNCs on a silicon platform. With the combination of a well-designed photonic crystal waveguide (PhCW filter and an elaborate single-slot PCNC, a specific high-order resonant mode was filtered for sensing. A 1 × 3 beam splitter carefully established was implemented to split channels and integrate three sensors to realize microarrays. By applying the three-dimensional finite-difference-time-domain (3D-FDTD method, the sensitivities calculated were S1 = 492 nm/RIU, S2 = 244 nm/RIU, and S3 = 552 nm/RIU, respectively. To the best of our knowledge, this is the first multiplexing design in which each sensor cite features such a high sensitivity simultaneously.

  11. A Novel Wideband Magneto-Electric Dipole Antenna with Improved Feeding Structure

    Directory of Open Access Journals (Sweden)

    N. Marwah

    2016-08-01

    Full Text Available A novel feeding structure in magneto-electric dipole antenna is proposed and analyzed, which is simpler and better in performance than previous designs, involving differential feeding.  Due to this improved feeding structure, the antenna has achieved an impedance bandwidth of 133.3% ( 0.5 GHz – 2.5 GHz, resulting into an ultra-wide band antenna. The maximum broadside gain 7.5dBi with unidirectional radiation pattern has also been reported for the entire the range of operation. Symmetry in E-plane and H-plane radiation patterns has been observed due to the symmetry in structure and excitation of antenna. The antenna has also been able to achieve cross polarization levels.

  12. Diagnostics and treatment of 1.3 GHz Nb cavities

    Energy Technology Data Exchange (ETDEWEB)

    Tamashevich, Yegor

    2017-01-15

    The European XFEL and the International Linear Collider are based on superconducting rf cavities. In order to reach the theoretical gradient limits of the superconducting cavities it is necessary to increase the mechanical quality and chemical composition of the inner surface as well as to understand the reason for performance limitations. This work is based on the diagnosis of over 100 XFEL and HiGrade cavities whose performance was limited by several factors: field emission on dust or surface defects, low-field thermal breakdown caused by the defects, Q-slope etc. It was found that some defects were produced during the mechanical production of the cavity and were not removed by electro-chemical polishing, a standard processing technique of the inner cavity surface. On the other hand, some of the defects were produced during the electro-chemical polishing process as the surface initially had imperfections or inclusions of foreign material. One of the opportunities to overcome the aforementioned drawbacks is to replace the ''bulk'' electro-chemical polishing process by mechanical centrifugal barrel polishing. The parameters of the surface after each polishing step were studied using small samples, so called coupons. An undersurface layer was investigated using metallographic techniques and cross sectioning. The influence of centrifugal polishing on the specific parameters of a 9-cell cavity (field flatness, eccentricity etc.) was investigated. As a result, a single-step centrifugal barrel polishing process followed by a standard ''light'' electropolishing was proposed for industrial application. Although the performance-limiting mechanisms are understood in general, the origin of the quench of the cavity is often unclear. To determine the quench locations, a localisation tool for thermal breakdown using the ''second sound'' in superfluid helium has been used. All components of this tool were improved to

  13. Diagnostics and treatment of 1.3 GHz Nb cavities

    International Nuclear Information System (INIS)

    Tamashevich, Yegor

    2017-01-01

    The European XFEL and the International Linear Collider are based on superconducting rf cavities. In order to reach the theoretical gradient limits of the superconducting cavities it is necessary to increase the mechanical quality and chemical composition of the inner surface as well as to understand the reason for performance limitations. This work is based on the diagnosis of over 100 XFEL and HiGrade cavities whose performance was limited by several factors: field emission on dust or surface defects, low-field thermal breakdown caused by the defects, Q-slope etc. It was found that some defects were produced during the mechanical production of the cavity and were not removed by electro-chemical polishing, a standard processing technique of the inner cavity surface. On the other hand, some of the defects were produced during the electro-chemical polishing process as the surface initially had imperfections or inclusions of foreign material. One of the opportunities to overcome the aforementioned drawbacks is to replace the ''bulk'' electro-chemical polishing process by mechanical centrifugal barrel polishing. The parameters of the surface after each polishing step were studied using small samples, so called coupons. An undersurface layer was investigated using metallographic techniques and cross sectioning. The influence of centrifugal polishing on the specific parameters of a 9-cell cavity (field flatness, eccentricity etc.) was investigated. As a result, a single-step centrifugal barrel polishing process followed by a standard ''light'' electropolishing was proposed for industrial application. Although the performance-limiting mechanisms are understood in general, the origin of the quench of the cavity is often unclear. To determine the quench locations, a localisation tool for thermal breakdown using the ''second sound'' in superfluid helium has been used. All components of this tool were improved to increase the accuracy of the measurements. A new program code

  14. Geothermal reservoirs. Position of slotted section of the tube casing

    International Nuclear Information System (INIS)

    Carotenuto, A.; Vanoli, L.; Casarosa, C.

    1999-01-01

    In the present work the authors have verified the influence of the position of slotted section casing on heat rate drawn by plants for exploitation of geothermal reservoirs that use heat exchangers placed at the bottom of the well (DHE). This study have been done modelling numerically the aquifer, by means of finite element method, evaluating the heat rate drawn by the heat exchanger at different position of the slotted section of the tube casing. Numerical calculations have allowed to show the influence of the main characteristics of the aquifer and of the main characteristics of the aquifer and of the plant on design of the slotted section of the tube casing. In particular, the authors have studied the influence of i) equivalent conductivity and permeability of the aquifer, ii) mass flow rate and the inlet and outlet aquifer temperature difference in the well, iii) the ratio between the length of the slotted section and the thickness of the geothermal layer, varying the position of the slotted section of the tube casing in the aquifer [it

  15. Vision-Based Parking-Slot Detection: A Benchmark and A Learning-Based Approach

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2018-03-01

    Full Text Available Recent years have witnessed a growing interest in developing automatic parking systems in the field of intelligent vehicles. However, how to effectively and efficiently locating parking-slots using a vision-based system is still an unresolved issue. Even more seriously, there is no publicly available labeled benchmark dataset for tuning and testing parking-slot detection algorithms. In this paper, we attempt to fill the above-mentioned research gaps to some extent and our contributions are twofold. Firstly, to facilitate the study of vision-based parking-slot detection, a large-scale parking-slot image database is established. This database comprises 8600 surround-view images collected from typical indoor and outdoor parking sites. For each image in this database, the marking-points and parking-slots are carefully labeled. Such a database can serve as a benchmark to design and validate parking-slot detection algorithms. Secondly, a learning-based parking-slot detection approach, namely P S D L , is proposed. Using P S D L , given a surround-view image, the marking-points will be detected first and then the valid parking-slots can be inferred. The efficacy and efficiency of P S D L have been corroborated on our database. It is expected that P S D L can serve as a baseline when the other researchers develop more sophisticated methods.

  16. Design of a Class of Antennas Utilizing MEMS, EBG and Septum Polarizers including Near-field Coupling Analysis

    Science.gov (United States)

    Kim, Ilkyu

    Recent developments in mobile communications have led to an increased appearance of short-range communications and high data-rate signal transmission. New technologies provides the need for an accurate near-field coupling analysis and novel antenna designs. An ability to effectively estimate the coupling within the near-field region is required to realize short-range communications. Currently, two common techniques that are applicable to the near-field coupling problem are 1) integral form of coupling formula and 2) generalized Friis formula. These formulas are investigated with an emphasis on straightforward calculation and accuracy for various distances between the two antennas. The coupling formulas are computed for a variety of antennas, and several antenna configurations are evaluated through full-wave simulation and indoor measurement in order to validate these techniques. In addition, this research aims to design multi-functional and high performance antennas based on MEMS (Microelectromechanical Systems) switches, EBG (Electromagnetic Bandgap) structures, and septum polarizers. A MEMS switch is incorporated into a slot loaded patch antenna to attain frequency reconfigurability. The resonant frequency of the patch antenna can be shifted using the MEM switch, which is actuated by the integrated bias networks. Furthermore, a high gain base-station antenna utilizing beam-tilting is designed to maximize gain for tilted beam applications. To realize this base-station antenna, an array of four dipole-EBG elements is constructed to implement a fixed down-tilt main beam with application in base station arrays. An improvement of the operating range with the EBG-dipole array is evaluated using a simple linkbudget analysis. The septum polarizer has been widely used in circularly polarized antenna systems due to its simple and compact design and high quality of circularity. In this research, the sigmoid function is used to smoothen the edge in the septum design, which

  17. Circular Microstrip Patch Array Antenna for C-Band Altimeter System

    Directory of Open Access Journals (Sweden)

    Asghar Keshtkar

    2008-01-01

    Full Text Available The purpose of this paper is to discuss the practical and experimental results obtained from the design, construction, and test of an array of circular microstrip elements. The aim of this antenna construction was to obtain a gain of 12 dB, an acceptable pattern, and a reasonable value of SWR for altimeter system application. In this paper, the cavity model was applied to analyze the patch and a proper combination of ordinary formulas; HPHFSS software and Microwave Office software were used. The array includes four circular elements with equal sizes and equal spacing and was planed on a substrate. The method of analysis, design, and development of this antenna array is explained completely here. The antenna is simulated and is completely analyzed by commercial HPHFSS software. Microwave Office 2006 software has been used to initially simulate and find the optimum design and results. Comparison between practical results and the results obtained from the simulation shows that we reached our goals by a great degree of validity.

  18. Modeling of Slot Waveguide Sensors Based on Polymeric Materials

    Science.gov (United States)

    Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

    2011-01-01

    Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

  19. Modeling of Slot Waveguide Sensors Based on Polymeric Materials

    Directory of Open Access Journals (Sweden)

    Lorenzo Pavesi

    2011-07-01

    Full Text Available Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies.

  20. Effects of antenna placement and antibiotic treatment on loss of simulated transmitters and mortality in hybrid striped bass

    Science.gov (United States)

    Isely, J.J.; Young, S.P.; Jones, T.A.; Schaffler, James J.

    2002-01-01

    We compared the effects of two antenna placements (trailing and nontrailing) and antibiotic treatments (treated and nontreated) on mortality and transmitter loss in hybrid striped bass Morone saxatilis ?? M. chrysops (364 ?? 28 mm total length, 645 ?? 129 g [mean ?? SD]) implanted with simulated transmitters and held in the laboratory for 90 d. Although antibiotic treatment significantly increased the time to first mortality in fish surgically implanted with simulated transmitters (by an average of 14 d), we did not detect an effect on cumulative mortality. We also did not detect an effect of antenna type on the time to first mortality, but cumulative mortality was higher in the trailing antenna groups (50%) than in the nontrailing antenna groups (12%). Three transmitters were expelled during the study, all from trailing-antenna treatment groups, indicating a significant effect of antenna placement on the level of transmitter expulsion. Antibiotic treatment appears to be effective in preventing initial postsurgical infection; however, the antenna may serve as a continuous source of irritation and route of infection into the body cavity. The potential for infection and mortality in experimental animals must be weighed against the improved performance of transmitters with trailing antennas.

  1. Investigation of slot discharge on a 239 MVA hydro generator stator winding

    Energy Technology Data Exchange (ETDEWEB)

    Li, S.; Hong, W. [BC Hydro and Power Authority, Vancouver, BC (Canada)

    2009-07-01

    This paper discussed a slot discharge investigation conducted on a 239 MVA generator stator winding. The generator in which the winding was located had experienced core split distortion, stator winding phase-to-phase failures, winding failures during Hipot testing, and high partial discharge (PD) activity. The results of on-line PD testing data were evaluated. The stator winding was subjected to visual inspections, bar dissections, and failure mechanism analyses. Eleven winding bars were removed from the stator slots in order to assess groundwall insulation conditions and identify the cause of the slot discharge activity. It was determined that the root cause of the slot discharge was a loose, non-uniform bar in the slot. The vibrating bar caused the semi-conductive coating to wear out and degraded the armour tape. Results of the study demonstrated the importance of on-line PD monitoring for detecting slot PD activity. 4 refs., 3 tabs., 11 figs.

  2. Collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation

    Science.gov (United States)

    Yang, Shangwen; Guo, Baohua; Xiao, Xuefei; Gao, Haichao

    2018-01-01

    To allocate the en-routes and slots to the flights with collaborative decision making, a collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation was proposed. Evaluation indexes include flight delay costs, delay time and the number of turning points. Analytic hierarchy process is applied to determining index weights. Remark set for current two flights not yet obtained the en-route and slot in flight schedule is established. Then, fuzzy comprehensive evaluation is performed, and the en-route and slot for the current two flights are determined. Continue selecting the flight not yet obtained an en-route and a slot in flight schedule. Perform fuzzy comprehensive evaluation until all flights have obtained the en-routes and slots. MatlabR2007b was applied to numerical test based on the simulated data of a civil en-route. Test results show that, compared with the traditional strategy of first come first service, the algorithm gains better effect. The effectiveness of the algorithm was verified.

  3. Sealing of minimally invasive Class II fillings (slot) using an adhesive patch: sealant margin extension for prevention.

    Science.gov (United States)

    Schmidlin, Patrick R; Seemann, Rainer; Filli, Tilla; Attin, Thomas; Imfeld, Thomas

    2007-01-01

    A laboratory study was performed to assess the potential of an adhesive patch to seal small, unbeveled, Class II, box-only (slot) composite fillings. After minimal access cavity preparation with an 80 pm diamond bur, 40 box-only Class II cavities were prepared mesially and distally in 20 extracted human molars using a u-shaped PCS insert (EMS). One cavity per tooth was adhesively filled with a hybrid composite material in one increment. A patch, acting as an adhesive matrice, was applied to the other cavity of each tooth to seal the restoration. The margin of the patch was located in areas easily accessible to oral hygiene measures and self-cleaning. All the teeth were subjected to thermo-mechanical stress in a computer-controlled masticator device. In 10 teeth, caries was induced in a microbial-based artificial mouth model and quantitatively determined by confocal laser scanning microscopy. Microleakage was assessed in the other 10 teeth in two planar sections after immersion in 0.5% basic fuchsin solution. The results showed no demineralization at the filling margins protected with the patch. Microleakage was observed in one sample only and was limited to the enamel. In contrast, the margins of fillings without the patch application showed a mean demineralization depth of 146 +/- 42 microm and dye penetration into the dentin in five sections. This innovative approach to sealing restorative margins with an adhesive patch results in less leakage and filling margin demineralization and merits further investigation.

  4. Terahertz repetition frequencies from harmonic mode-locked monolithic compound-cavity laser diodes

    International Nuclear Information System (INIS)

    Yanson, D. A.; Street, M. W.; McDougall, S. D.; Thayne, I. G.; Marsh, J. H.; Avrutin, E. A.

    2001-01-01

    Compound-cavity laser diodes are mode locked at a harmonic of the fundamental round-trip frequency to achieve repetition rates of up to 2.1 THz. The devices are fabricated from GaAs/AlGaAs material at a wavelength of 860 nm and incorporate two gain sections with an etched slot reflector between them, and a saturable absorber section. Autocorrelation studies are used to investigate device behavior for different reflector types and reflectivity. These lasers may find applications in terahertz imaging, medicine, ultrafast optical links, and atmospheric sensing. [copyright] 2001 American Institute of Physics

  5. Energy characteristics of the double slot in the narrow wall of a rectangular waveguide

    OpenAIRE

    Martynenko, S. A.

    2005-01-01

    Based on approximation of the half-wave field distribution in the slots, an expression is derived for internal mutual conductance of closely-spaced slots, which form a double inclined slot in the narrow wall of a rectangular waveguide. The narrow wall has cut-outs reaching the broad wall. With the use of the method of induced magnetomotive forces, a mathematical model is devised for calculating the energy characteristics of the double slot. The impact of angle of inclination of the slots, dim...

  6. Design of high-gain, wideband antenna using microwave hyperbolic metasurface

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yan, E-mail: yan.z@chula.ac.th [International School of Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330 (Thailand)

    2016-05-15

    In this work, we apply hyperbolic metasurfaces (HMSs) to design high-gain and wideband antennas. It is shown that HMSs formed by a single layer of split-ring resonators (SRRs) can be excited to generate highly directive beams. In particular, we suggest two types of the SRR-HMS: a capacitively loaded SRR (CLSRR)-HMS and a substrate-backed double SRR (DSRR)-HMS. Both configurations ensure that the periodicity of the structures is sufficiently small for satisfying the effective medium theory. For the antenna design, we propose a two-layer-stacked configuration for the 2.4 GHz frequency band based on the DSRR-HMS excited by a folded monopole. Measurement results confirm numerical simulations and demonstrate that an antenna gain of more than 5 dBi can be obtained for the frequency range of 2.1 - 2.6 GHz, with a maximum gain of 7.8 dBi at 2.4 GHz.

  7. Distributed Subarray Antennas for Multifunction Phased-Array Radar

    National Research Council Canada - National Science Library

    Lin, Chih-heng

    2003-01-01

    As the target radar cross section (RCS) continuously decreases, the need for high-resolution high-gain radar increases, One approach to high resolution is to use distributed subarray antennas (DSAs...

  8. An experimental study of Alfven wave heating using electrostatically shielded antennas in TCA

    International Nuclear Information System (INIS)

    Borg, G.G.; Joye, B.

    1990-01-01

    Despite the wide acceptance of electrostatic screens in ICRH for the protection of the plasma from the near fields of rf antennas, it has always been considered that low voltages at low frequency have made such screens unnecessary in Alfven wave heating (AWH). Despite this, AWH performs rather poorly as a heating method; the results being confused by a density rise up to 300 % of the target density. It is known that the density increase arises neither from impurity injection nor from a change in recycling. In addition, an extensive range of phenomena have been observed in the plasma scrape-off layer (SOL). During AWH, the SOL density is observed to decrease, the SOL floating potential is perturbed in a way that reflects the Alfven wave spectrum, the antennas charge negatively and draw a large current from the plasma and harmonics have been observed on the edge wave fields. The cause and correlation of these effects with each other and their impression on the bulk plasma response was not known. Experimental results from the TORTUS tokamak have indicated that the density increase might be eliminated by electrostatic screens. In their case, two AWH experiments were performed. In the first, an unshielded OFHC copper loop antenna was excited at a given power and, in the second, the same antenna was excited at the same power after installation of an aluminium, TiN coated, slotted screen. The density increase in the first case was shown to be completely eliminated in the second, although spectroscopic measurements revealed a difference in the plasma O(II) and Cu(I) content for each case. (author) 2 refs., 3 figs

  9. Broadcast Coded Slotted ALOHA

    DEFF Research Database (Denmark)

    Ivanov, Mikhail; Brännström, Frederik; Graell i Amat, Alexandre

    2016-01-01

    We propose an uncoordinated medium access control (MAC) protocol, called all-to-all broadcast coded slotted ALOHA (B-CSA) for reliable all-to-all broadcast with strict latency constraints. In B-CSA, each user acts as both transmitter and receiver in a half-duplex mode. The half-duplex mode gives ...

  10. Results of pressurized-slot measurements in the G-Tunnel underground facility

    International Nuclear Information System (INIS)

    Zimmerman, R.M.; Mann, K.L.; Dodds, D.J.

    1989-01-01

    A rock-mechanics field-testing program is underway at Sandia National Laboratories (SNL) as part of the YMP. SNL has the responsibility for assessing the repository design and performance as well as characterizing the geomechanical behavior of the rock. SNL has conducted field experiments in G-Tunnel in Rainier Mesa at the NTS, where tuffs similar to those at Yucca Mountain, the potential repository site, are found. Later experiments are planned as part of the YMP Exploratory Shaft investigations at Yucca Mountain. Major geomechanical factors in repository developments are determinations of the stress state and the deformability of the rock mass (described by the modulus of deformation). One feature of SNL's rock-mechanics program was the development of a testing program for cutting thin slots in a jointed welded tuff and utilizing flatjacks for pressurizing these thin-slots on a relatively, large scale. Objectives in the pressurized-slot testing in G-Tunnel have been to apply and possibly improve methods for (1) utilizing the flatjack cancellation (FC) method for measuring stresses normal to the slot and (2) measuring the modulus of deformation of the jointed rock surrounding the slot. This paper discusses the results of field measurements in and around a single slot and evaluates potential applications and limitations. 10 refs., 1 fig., 4 tabs

  11. Slot-dimer babinet metamaterials as polarization shapers for terahertz waves

    DEFF Research Database (Denmark)

    Zhukovsky, Sergei; Chigrin, D. N.; Lavrinenko, Andrei

    2013-01-01

    We theoretically study optical properties of free-standing metallic membranes patterned with an array of two-slot elements (dimers) comprising two rectangular slots of different dimensions and orientation. It is shown that these structures feature extraordinary optical transmission with strong...

  12. An interstitial miniature antenna for localized in vivo 31P spectroscopy

    International Nuclear Information System (INIS)

    Hentschel, M.; Wust, P.; Faehling, H.; Richter, R.; Vogl, T.; Semmler, W.; Wolf, K.J.; Felix, R.

    1996-01-01

    Phosphorus spectroscopy can be used to assess response in tumor therapy and to monitor response. Methodical problems of localisation and contamination make it more difficult to interpret and reproduce the spectra. Interstitial and endoluminal spectroscopy antennas placed directly within or close to the tumor could provide help in this problem. We developed an interstitial 31 P MRS antenna together with a tuning network which can be used in thermometry catheters for hyperthermia within an internal lumen of 1.1 mm in diameter. A prototype of this type of miniature antenna suitable for use in Siemens MRI scanners at 1.5 T was described spectroscopically with regard to excitation profile, range and SNR. Results: In terms of quality, the excitation profiles of the interstitial antennas in relation to orientation correspond to those of comparable but considerably larger endocavitary antennas and catheter coils for MR imaging and spectroscopy. Maximum sensitivity was achieved by aligning the coil normal perpendicular to the B 0 field. Signal losses of up to 50% have to be reckoned with when using other orientations. The maximum range of the interstitial antenna was determined using spectroscopy and was found to be 5 mm, i.e. 9 times coil radius. The sensitivity of the studied type of interstitial antenna allows in vivo 31 P spectroscopy to be performed despite the unusually low axial dimension (coil radius r=0.55 mm). The prototype of the described interstitial antenna was used to measure an in vivo spectrum from the back muscle of a rabbit in 10 min. Nevertheless, the detection volume of at least some ml necessary for 31 P spectroscopy results mainly from the large antenna length. Conclusion: The sensitivity of the interstitial antenna needs to be further improved in order to assess treatment response in patients. (orig./MG) [de

  13. The Use of Conductive Ink in Antenna Education and Design

    Science.gov (United States)

    Addison, David W.

    Conductive ink from a printer allows for the fabrication of conductive material with tight tolerances without the cost and time of chemical etching. This paper explores the use of AGIC printable conductive ink on a paper substrate as design tool for antennas as well as classroom use in antenna education. The antenna designs satisfy the requirements of a compact Global Navigation Satellite System (GNSS) antenna while showing a competitive performance within the current market. One best design is shown along with three other structures. These antennas consist of a bowtie cross-dipole over a reflective disc with conductive-ink grounded structures. In addition to the GNSS antennas, a linear elliptical dipole over a reflective disc with conductive grounded structures is presented. This elliptical antenna design attempts to find the maximum impedance bandwidth beyond the GNSS band. The inexpensive nature of conductive ink allows for its use in a classroom to demonstrate antenna behavior as part of antenna education. An inexpensive approach to the patch antenna using conductive ink is described and paired with a system made of off-the-shelf parts. The system is capable of measuring the power of the received signal. The received signal measurement is not as accurate as using a anechoic chamber but pattern details are visible. This is used to demonstrate aspects of the Friis transmission equation such as distance, polarization, radiation pattern shape, and loss.

  14. Robustness of plasmonic angular momentum confinement in cross resonant optical antennas

    Energy Technology Data Exchange (ETDEWEB)

    Klaer, Peter; Lehr, Martin; Krewer, Keno; Schertz, Florian; Schönhense, Gerd; Elmers, Hans Joachim, E-mail: elmers@uni-mainz.de [Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz (Germany); Razinskas, Gary; Wu, Xiao-Fei; Hecht, Bert [Institut für Physik, Julius-Maximilians-Universität, Am Hubland, 97074 Würzburg (Germany)

    2015-06-29

    Using a combination of photoemission electron microscopy and numerical simulations, we investigated the angular moment transfer in strongly enhanced optical near-fields of artificially fabricated optical antennas. The polarization dependence of the optical near-field enhancement has been measured in a maximum symmetric geometry, i.e., excitation by a normal incident planar wave. Finite-difference time-domain simulations for the realistic antenna geometries as determined by high-resolution electron microscopy reveal a very good agreement with experimental data. The agreement confirms that the geometrical asymmetries and inhomogeneities due to the nanoscale fabrication process preserve the circular polarization in the gap regions with strong near-field enhancement.

  15. LHC crab-cavity aspects and strategy

    International Nuclear Information System (INIS)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-01-01

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  16. Measurement Report for the Four-Rod LHC Crab Cavity. Cold Tests held in July 2014

    CERN Document Server

    Navarro Tapia, Maria; Calaga, Rama; Hernandez Chahin, Karim Gibran; Junginger, Tobias; Macpherson, Alick; Torres-Sanchez, Roberto; CERN. Geneva. ATS Department

    2015-01-01

    The performance of the four-rod cavity prototype considered for the HL-LHC upgrade has already been assessed at CERN at cryogenic temperatures three times in the last two years [1, 2, 3]. In this report, the results of the latest measurements, carried out in July 2014, are shown. These measurements were to check the improvement of the cavity performance due to the change of the input and pick-up antennas. An estimation of the residual resistance of the Niobium was also performed.

  17. Measurement of the depth of narrow slotted sections in eddy current reference standards

    Science.gov (United States)

    Kim, Young-Joo; Kim, Young-gil; Ahn, Bongyoung; Yoon, Dong-Jin

    2007-02-01

    The dimensions of the slots in eddy current (EC) reference standards are too narrow to be measured by general depth measurement methods such as the optical (laser) or stylus methods. However, measurement of the dimensions of the machined slots is a prerequisite to using the blocks as references. The present paper suggests a measurement method for the slotted section using an ultrasonic test. The width and depth of the slots measured in our study are roughly 0.1 mm and 0.5 mm, respectively. The time of flight (TOF) of the ultrasonic wave was measured precisely. The ultrasonic velocity in the material of the EC reference standard was calculated with the measured values of the TOF and its thickness. Reflected waves from the tip of the slot and the bottom surface of the EC standard were successfully classified. Using this method we have successfully determined the depth of the slotted section.

  18. Slot-type pickup/kicker for AA stochastic cooling

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    A "slotted transmission line" was used for both pickups and kickers of the cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. Here we see the slotted electrodes partly pulled out of the outer casing. See also 7906189, 7906581X, 7896193.

  19. Utilizing wideband AMC structures for high-gain inkjet-printed antennas on lossy paper substrate

    KAUST Repository

    Cook, Benjamin Stassen

    2013-01-01

    Significant gain and bandwidth improvement of inkjet-printed antennas with integrated artificial magnetic conductor (AMC) is achieved by utilizing wideband ground-backed frequency selective surfaces (FSSs) to overcome the high losses of organic substrates such as paper. A microstrip-fed monopole mounted on an artificial magnetic conductor is demonstrated to improve the gain by 5 dB over previous works and exhibit much wider impedance bandwidth while maintaining a thin antenna profile and a 20% electrical size reduction. The effect of AMC bandwidth on substrate losses and the gain reduction caused by finite AMC array effects are investigated in an effort to produce high-gain, miniaturized, low-cost wearable and structure mount antennas. © 2013 IEEE.

  20. Feasibility of antenna-to-antenna isolation measurements at S-band in the Facility for Antenna and Radar-cross-section Measurements (FARM)

    Energy Technology Data Exchange (ETDEWEB)

    Brock, Billy C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-01-01

    Frequency-domain antenna-coupling measurements performed in the compact-range room of the FARM, will actually be dominated by reflected components from the ceiling, floor, walls, etc., not the direct freespace coupling. Consequently, signal processing must be applied to the frequency-domain data to extract the direct free-space coupling. The analysis presented above demonstrates that it is possible to do so successfully.