Calculation of the self-consistent current distribution and coupling of an RF antenna array

International Nuclear Information System (INIS)

Ballico, M.; Puri, S.

1993-10-01

A self-consistent calculation of the antenna current distribution and fields in an axisymmetric cylindrical geometry for the ICRH antenna-plasma coupling problem is presented. Several features distinguish this calculation from other codes presently available. 1. Variational form: The formulation of the self consistent antenna current problem in a variational form allows good convergence and stability of the algorithm. 2. Multiple straps: Allows modelling of (a) the current distribution across the width of the strap (by dividing it up into sub straps) (b) side limiters and septum (c) antenna cross-coupling. 3. Analytic calculation of the antenna field and calculation of the antenna self-consistent current distribution, (given the surface impedance matrix) gives rapid calculation. 4. Framed for parallel computation on several different parallel architectures (as well as serial) gives a large speed improvement to the user. Results are presented for both Alfven wave heating and current drive antenna arrays, showing the optimal coupling to be achieved for toroidal mode numbers 8< n<10 for typical ASDEX upgrade plasmas. Simulations of the ASDEX upgrade antenna show the importance of the current distribution across the antenna and of image currents flowing in the side limiters, and an analysis of a proposed asymmetric ITER antenna is presented. (orig.)

Sequential modelling of ICRF wave near RF fields and asymptotic RF sheaths description for AUG ICRF antennas

Directory of Open Access Journals (Sweden)

Jacquot Jonathan

2017-01-01

Full Text Available A sequence of simulations is performed with RAPLICASOL and SSWICH to compare two AUG ICRF antennas. RAPLICASOL outputs have been used as input to SSWICH-SW for the AUG ICRF antennas. Using parallel electric field maps and the scattering matrix produced by RAPLICASOL, SSWICH-SW, reduced to its asymptotic part, is able to produce a 2D radial/poloidal map of the DC plasma potential accounting for the antenna input settings (total power, power balance, phasing. Two models of antennas are compared: 2-strap antenna vs 3-strap antenna. The 2D DC potential structures are correlated to structures of the parallel electric field map for different phasing and power balance. The overall DC plasma potential on the 3-strap antenna is lower due to better global RF currents compensation. Spatial proximity between regions of high RF electric field and regions where high DC plasma potentials are observed is an important factor for sheath rectification.

Recent developments in ICRF antenna modelling

International Nuclear Information System (INIS)

Lamalle, P.U.; Messiaen, A.M.; Dumortier, P.; Louche, F.

2005-01-01

The antennas presently developed for ICRF heating of the ITER plasma consist of a tightly packed array of a large number of radiating straps, in order to deliver a high power density without exceeding radio-frequency voltage standoffs. Recently developed commercial software has enabled important progress in the coupling analysis and optimisation of such demanding systems. Approximations allowing to convincingly include a realistic plasma description in these codes are discussed. Application of the resulting numerical tools is illustrated by simulation of the existing JET A2 ICRF array, with the goal to validate simulations for future antennas. Advances in the design of realistic test bed conditions, using salted water as a means of creating plasma-relevant antenna loading, and the appropriate scaling of a mockup are also presented. (author)

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.

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.

Combline antenna modeling for plasma heating

International Nuclear Information System (INIS)

Nelson, S.D.; Kamin, G.; Van Maren, R.; Poole, B.; Moeller, C.; Phelps, D.

1996-01-01

The combline antenna for plasma heating, as proposed by General Atomics(1), has unique potential for solving many plasma drive problems. The benefit of the combline design is the utilization of the coupling between elements that avoids a more cumbersome multidrive system. This design is being investigated using computational EM modeling codes in the 100 endash 400 MHz band using resources at General Atomics and LLNL. Preliminary experimental results, using a combline mockup, agree well with 3D modeling efforts including resonant frequency alignment and amplitudes. These efforts have been expanded into an endeavor to optimize the combline design using both time and frequency domain codes. This analysis will include plasma coupling but to date has been limited to antenna effects. The combline antenna system is modeled in 3D using a combination of computational tools in the time domain, for temporal feature isolation purposes, and in the frequency domain, for resonant structure analysis. Both time and frequency domain modeling details include the Faraday shield elements, the strap elements, and the feed structure. copyright 1996 American Institute of Physics

A Newly Designed Tennis Elbow Orthosis With a Traditional Tennis Elbow Strap in Patients With Lateral Epicondylitis

Science.gov (United States)

Saremi, Hossein; Chamani, Vahid; Vahab-Kashani, Reza

2016-01-01

Background Lateral epicondylitis is a common cause of pain and upper limb dysfunction. The use of counterforce straps for treatment of lateral epicondylitis is widespread. This kind of orthosis can be modified to have a greater effect on relieving pain by reducing tension on the origin of the extensor pronator muscles. Objectives To determine the immediate effects of a newly designed orthosis on pain and grip strength in patients with lateral epicondylitis. Materials and Methods Twelve participants (six men and six women) were recruited (mean age = 41 ± 6.7 years) and evaluated for pain and grip strength in three sessions. A 48-hour break was taken between each session. The first session was without any orthosis, the second session was with the new modified tennis elbow orthosis, and the third session was with a conventional tennis elbow strap. Results Both counterforce straps were effective. However, significantly more improvement was observed in pain and grip strength after using the newly modified orthosis (P < 0.05). Conclusions The newly designed strap reduces pain more effectively and improves grip strength by causing greater localized pressure on two regions with different force applications (two component vectors versus one). PMID:28180116

A Newly Designed Tennis Elbow Orthosis With a Traditional Tennis Elbow Strap in Patients With Lateral Epicondylitis.

Science.gov (United States)

Saremi, Hossein; Chamani, Vahid; Vahab-Kashani, Reza

2016-07-01

Lateral epicondylitis is a common cause of pain and upper limb dysfunction. The use of counterforce straps for treatment of lateral epicondylitis is widespread. This kind of orthosis can be modified to have a greater effect on relieving pain by reducing tension on the origin of the extensor pronator muscles. To determine the immediate effects of a newly designed orthosis on pain and grip strength in patients with lateral epicondylitis. Twelve participants (six men and six women) were recruited (mean age = 41 ± 6.7 years) and evaluated for pain and grip strength in three sessions. A 48-hour break was taken between each session. The first session was without any orthosis, the second session was with the new modified tennis elbow orthosis, and the third session was with a conventional tennis elbow strap. Both counterforce straps were effective. However, significantly more improvement was observed in pain and grip strength after using the newly modified orthosis (P < 0.05). The newly designed strap reduces pain more effectively and improves grip strength by causing greater localized pressure on two regions with different force applications (two component vectors versus one).

Thermo-mechanical analysis of the ICRH antenna for the ignitor experiment

International Nuclear Information System (INIS)

Salvetti, M.F.; Berruti, T.; Gola, M.M.

2005-01-01

This paper presents the design of the ion cyclotron resonance heating (ICRH) system of the ignitor machine. In addition, the paper presents relevant calculations and the design solutions adopted for the ICRH antenna straps. The thermal-mechanical analysis of the structure is illustrated. The displacements and stresses due to thermal loading and to dynamic loads induced during plasma vertical disruptions events (VDE) are calculated. The capability of carrying out both the assembly and maintenance of the antennas' components in full remote handling (RH) conditions is one of the specifications to which the design has to comply. A mechanical design that guarantees ease of operation is discussed. The proposed solution minimizes the variety of movements required for the manipulator

Negative Rotation Cinch Strap.

Science.gov (United States)

This project discloses an improved unitary parachute torso harness, having a single fastening means, wherein an auxillary tightening strap is...attached to the groin straps of said harness. Said auxillary straps are used to prevent torso rotation or harness slippage and to prevent harness elongation

Design of LTCC Based Fractal Antenna

KAUST Repository

AdbulGhaffar, Farhan

2010-09-01

The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array has been designed for the first time on Low Temperature Co-fired Ceramic (LTCC) based substrate. LTCC provides a suitable platform for the development of these antennas due to its properties of vertical stack up and embedded passives. The complete antenna concept involves integration of this fractal antenna array with a Fresnel lens antenna providing a total gain of 15dB which is appropriate for medium range radar applications. The thesis also presents a comparison between the designed fractal antenna and a conventional patch antenna outlining the advantages of fractal antenna over the later one. The fractal antenna has a bandwidth of 1.8 GHz which is 7.5% of the centre frequency (24GHz) as compared to 1.9% of the conventional patch antenna. Furthermore the fractal design exhibits a size reduction of 53% as compared to the patch antenna. In the end a sensitivity analysis is carried out for the fractal antenna design depicting the robustness of the proposed design against the typical LTCC fabrication tolerances.

ICRF antenna and feedthrough development at ORNL

International Nuclear Information System (INIS)

Baity, F.W.; Bryan, W.E.; Hoffman, D.J.; Owens, T.L.; Rettig, C.L.; Schechter, D.E.

1985-01-01

The rf technology program at Oak Ridge National Laboratory is highlighted. Simply stated, the objective of the program is to develop the technology for ion cyclotron range of frequencies heating of the fusion machines leading up to a reactor. Results from an investigation of the importance of current strap shaping in compact antenna design are presented. Designs of the Doublet III-D and Advanced Toroidal Facility compact loop launchers are described, as are the vacuum feedthroughs for the West German tokamak TEXTOR and the Tandem Mirror Experiment Upgrade (TMX-U)

Electromagnetic simulations of the ASDEX Upgrade ICRF Antenna with the TOPICA code

International Nuclear Information System (INIS)

Krivska, A.; Milanesio, D.; Bobkov, V.; Braun, F.; Noterdaeme, J.-M.

2009-01-01

Accurate and efficient simulation tools are necessary to optimize the ICRF antenna design for a set of operational conditions. The TOPICA code was developed for performance prediction and for the analysis of ICRF antenna systems in the presence of plasma, given realistic antenna geometries. Fully 3D antenna geometries can be adopted in TOPICA, just as in available commercial codes. But while those commercial codes cannot operate with a plasma loading, the TOPICA code correctly accounts for realistic plasma loading conditions, by means of the coupling with 1D FELICE code. This paper presents the evaluation of the electric current distribution on the structure, of the parallel electric field in the region between the straps and the plasma and the computation of sheaths driving RF potentials. Results of TOPICA simulations will help to optimize and re-design the ICRF ASDEX Upgrade antenna in order to reduce tungsten (W) sputtering attributed to the rectified sheath effect during ICRF operation.

Traveling wave antenna for fast wave heating and current drive in tokamaks

International Nuclear Information System (INIS)

Ikezi, H.; Phelps, D.A.

1995-07-01

The traveling wave antenna for heating and current drive in the ion cyclotron range of frequencies is shown theoretically to have loading and wavenumber spectrum which are largely independent of plasma conditions. These characteristics have been demonstrated in low power experiments on the DIII-D tokamak, in which a standard four-strap antenna was converted to a traveling wave antenna through use of external coupling elements. The experiments indicate that the array maintains good impedance matching without dynamic tuning during abrupt changes in the plasma, such as during L- to H-mode transitions, edge localized mode activity, and disruptions. An analytic model was developed which exhibits the features observed in the experiments. Guidelines for the design of traveling wave antennas are derived from the validated model

Design of broadband single polarized antenna

Science.gov (United States)

Shin, Phoo Kho; Aziz, Mohamad Zoinol Abidin Abd.; Ahmad, Badrul Hisham; Ramli, Mohamad Hafize Bin; Fauzi, Noor Azamiah Md; Malek, Mohd Fareq Abd

2015-05-01

In practical wireless communication application, bandwidth enhancement becomes one of the major design considerations. At the same time, circular polarized (CP) antenna received much attention for the applications of modern wireless communication system when compared to linear polarized (LP) antenna. This is because CP antenna can reduce the multipath effect. Hence, broadband antenna with operating frequency at 2.4GHz for WLAN application is proposed. The proposed antenna is done by using L-probe amendment with rectangular patch. The rectangular patch and copper ground plane is separated with 10mm air gap. This approach is used to enhance the bandwidth and the gain of the proposed antenna. The bandwidth of the designed antenna is more than 200MHz which meet broadband application. The return loss for the antenna is below -10dB to achieved 90% matching efficiency. The position of L-probe feed is altered in order to obtained different polarizations. The broadband antenna had been designed and simulated by using Computer Simulation Technology (CST) software. In this paper, the comparison for single polarized antenna with the design of non-inverted patch and inverted patch is discussed. The characteristics of the S-parameter, axial ratio, gain, surface current for each designed antenna are analyzed.

KISS for STRAP: user extensions for a protein alignment editor.

Science.gov (United States)

Gille, Christoph; Lorenzen, Stephan; Michalsky, Elke; Frömmel, Cornelius

2003-12-12

The Structural Alignment Program STRAP is a comfortable comprehensive editor and analyzing tool for protein alignments. A wide range of functions related to protein sequences and protein structures are accessible with an intuitive graphical interface. Recent features include mapping of mutations and polymorphisms onto structures and production of high quality figures for publication. Here we address the general problem of multi-purpose program packages to keep up with the rapid development of bioinformatical methods and the demand for specific program functions. STRAP was remade implementing a novel design which aims at Keeping Interfaces in STRAP Simple (KISS). KISS renders STRAP extendable to bio-scientists as well as to bio-informaticians. Scientists with basic computer skills are capable of implementing statistical methods or embedding existing bioinformatical tools in STRAP themselves. For bio-informaticians STRAP may serve as an environment for rapid prototyping and testing of complex algorithms such as automatic alignment algorithms or phylogenetic methods. Further, STRAP can be applied as an interactive web applet to present data related to a particular protein family and as a teaching tool. JAVA-1.4 or higher. http://www.charite.de/bioinf/strap/

GPS antenna designs

Science.gov (United States)

Laube, Samuel J. P.

1987-05-01

Application of the current GPS NAVSTAR system to civilian service requires that a right hand, circularly polarized, -160 dBW spread spectrum signal be received from an orbiting satellite, where the antenna environment is also moving. This presents a design challenge when inexpensive antennas are desired. The intent of this survey is to provide information on the antennas mentioned and to construct and test prototypes to determine whether the choice made by the industry, the quadrifilar helix, is the best. The helix antenna is currently the low cost standard for GPS. Prototype versions were constructed using 12 gauge wire and subminiature coaxial hardline. The constructed antennas were tested using a signal generator and a reference turnstile. A spectrum analyzer was used to measure the level of the received signal.

Traveling-wave antenna for fast-wave heating and current drive in tokamaks

International Nuclear Information System (INIS)

Ikezi, H.; Phelps, D.A.

1997-01-01

The travelling-wave antenna for heating and current drive in the ion cyclotron range of frequencies is shown theoretically to have loading and wavenumber spectra that are largely independent of plasma conditions. These characteristics have been demonstrated in low-power experiments on the DIII-D tokamak, in which a standard four-strap antenna was converted to a traveling-wave antenna through use of external coupling elements. The experiments indicate that the array maintains good impedance matching without dynamic tuning during abrupt changes in the plasma, such as during L- to H-mode transitions, edge-localized mode activity, and disruptions. An analytic model was developed that exhibits the features observed in the experiments. Guidelines for the design of travelling-wave antennas are derived from the validated model. 11 refs., 14 figs

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)

Antenna theory: Analysis and design

Science.gov (United States)

Balanis, C. A.

The book's main objective is to introduce the fundamental principles of antenna theory and to apply them to the analysis, design, and measurements of antennas. In a description of antennas, the radiation mechanism is discussed along with the current distribution on a thin wire. Fundamental parameters of antennas are examined, taking into account the radiation pattern, radiation power density, radiation intensity, directivity, numerical techniques, gain, antenna efficiency, half-power beamwidth, beam efficiency, bandwidth, polarization, input impedance, and antenna temperature. Attention is given to radiation integrals and auxiliary potential functions, linear wire antennas, loop antennas, linear and circular arrays, self- and mutual impedances of linear elements and arrays, broadband dipoles and matching techniques, traveling wave and broadband antennas, frequency independent antennas and antenna miniaturization, the geometrical theory of diffraction, horns, reflectors and lens antennas, antenna synthesis and continuous sources, and antenna measurements.

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

Patient restraining strap for scintiphotography

International Nuclear Information System (INIS)

Kay, T.D.; Harper, J.W.

1976-01-01

A patient restraining strap for scintiphotography having a pair of expandable cloth-like bags joined together is presented. The strap encompasses the head of a patient and is then secured to a Gamma Scintillation Camera. Once inflated the restraining strap immobilizes the head without discomfort to the patient during the scintiphotography procedure. 1 claim, 1 drawing figure

Reflectarray antennas theory, designs, and applications

CERN Document Server

Nayeri, Payam; Elsherbeni, Atef Z

2018-01-01

This book provides engineers with a comprehensive review of the state-of-the-art in reflectarray antenna research and development. The authors describe, in detail, design procedures for a wide range of applications, including broadband, multi-band, multi-beam, contour-beam, beam-scanning, and conformal reflectarray antennas. They provide sufficient coverage of basic reflectarray theory to fully understand reflectarray antenna design and analysis such that the readers can pursue reflectarray research on their own. Throughout the book numerous illustrative design examples including numerical and experimental results are provided. Featuring in-depth theoretical analysis along with practical design examples, Reflectarray Antennas is an excellent text/reference for engineering graduate students, researchers, and engineers in the field of antennas. It belongs on the bookshelves of university libraries, research institutes, and industrial labs and research facilities.

Plasma-surface interactions with ICRF antennas and lower hybrid grills in Tore Supra

Energy Technology Data Exchange (ETDEWEB)

Harris, J.H. [Oak Ridge National Lab., TN (United States); Hutter, T. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Hogan, J.T. [Oak Ridge National Lab., TN (United States)] [and others

1996-10-01

The edge plasma interactions of the actively cooled radio-frequency heating launchers in Tore Supra- ion-cyclotron range-of-frequencies (ICRF) antennas and lower-hybrid (LH) grills-are studied using infrared video imaging. On the two-strap ICRF antennas, operated in fast-wave electron heating or current drive mode, hot spots with temperatures of 500-900{degrees} C are observed by the end of 2-s power pulses of 2 MW per antenna. The distribution and maximum values of temperature are determined principally by the relative phase of the two antenna straps: dipole (heating) phasing results in significantly less antenna heating than does 90` (current drive) phasing. Transient heat fluxes of 1-20 MW/m{sup 2} are measured on the lateral protection bumpers at ICRF turn-on; these fluxes are primarily a function of plasma and radio frequency (rf) control, and are not simply correlated with the strap phasing or the final surface temperature distributions. The remarkable feature of the lower hybrid edge interaction is the production of beams of heat flux in front of the grills; these beams propagate along the helical magnetic field lines and can deliver fluxes of 5-10 MW/m{sup 2} over areas of several cm{sup 2} to plasma-facing components such as the grill or antenna lateral bumpers. Both the ICRF and LH phenomena appear to result from the acceleration of particles by the near fields of the launchers. Modeling of the heat flux deposition on components and its relation to sputtering processes is presented, and possibilities for controlling these interactions are discussed.

Low-cost Antenna Positioning System Designed with Axiomatic Design

Directory of Open Access Journals (Sweden)

Timothy Foley Joseph

2017-01-01

Full Text Available The Engineering Optimization and Modeling Center at Reykjavik University has been carrying out research on antenna CAD, including the simulation-driven design of novel antenna topologies. However, simulation is not enough to validate a design: a custom RF anechoic chamber has been built to quantify antenna performance, particularly in terms of field properties such as radiation patterns. Such experiments require careful positioning of the antenna in the chamber accurately in 3-axis with a short development time, challenging material constraints, and minimal funding. Axiomatic Design Theory principles were applied to develop an automated 3-axis positioner system for a reference antenna and the antenna to be calibrated. Each axis can be individually controlled with a repeatability of 1 degree. This 3000 USD device can be fabricated using easily available components and rapid prototyping tools.

Ultra wideband antennas design, methodologies, and performance

CERN Document Server

Galvan-Tejada, Giselle M; Jardón Aguilar, Hildeberto

2015-01-01

Ultra Wideband Antennas: Design, Methodologies, and Performance presents the current state of the art of ultra wideband (UWB) antennas, from theory specific for these radiators to guidelines for the design of omnidirectional and directional UWB antennas. Offering a comprehensive overview of the latest UWB antenna research and development, this book:Discusses the developed theory for UWB antennas in frequency and time domainsDelivers a brief exposition of numerical methods for electromagnetics oriented to antennasDescribes solid-planar equivalen

A Modal Approach to Compact MIMO Antenna Design

Science.gov (United States)

Yang, Binbin

MIMO (Multiple-Input Multiple-Output) technology offers new possibilities for wireless communication through transmission over multiple spatial channels, and enables linear increases in spectral efficiency as the number of the transmitting and receiving antennas increases. However, the physical implementation of such systems in compact devices encounters many physical constraints mainly from the design of multi-antennas. First, an antenna's bandwidth decreases dramatically as its electrical size reduces, a fact known as antenna Q limit; secondly, multiple antennas closely spaced tend to couple with each other, undermining MIMO performance. Though different MIMO antenna designs have been proposed in the literature, there is still a lack of a systematic design methodology and knowledge of performance limits. In this dissertation, we employ characteristic mode theory (CMT) as a powerful tool for MIMO antenna analysis and design. CMT allows us to examine each physical mode of the antenna aperture, and to access its many physical parameters without even exciting the antenna. For the first time, we propose efficient circuit models for MIMO antennas of arbitrary geometry using this modal decomposition technique. Those circuit models demonstrate the powerful physical insight of CMT for MIMO antenna modeling, and simplify MIMO antenna design problem to just the design of specific antenna structural modes and a modal feed network, making possible the separate design of antenna aperture and feeds. We therefore develop a feed-independent shape synthesis technique for optimization of broadband multi-mode apertures. Combining the shape synthesis and circuit modeling techniques for MIMO antennas, we propose a shape-first feed-next design methodology for MIMO antennas, and designed and fabricated two planar MIMO antennas, each occupying an aperture much smaller than the regular size of lambda/2 x lambda/2. Facilitated by the newly developed source formulation for antenna stored

A Design of Double Broadband MIMO Antenna

Directory of Open Access Journals (Sweden)

Yanfeng Geng

2015-01-01

Full Text Available The MIMO antenna applied to LTE mobile system should be miniaturization and can work in the current communication frequency band; isolation between each antenna unit also should be good so as to reduce loss of radio wave energy and improve the antenna performance of the MIMO system. This paper puts forward the design scheme of a broadband MIMO double antenna. And the design of antenna unit and debugging and related technical measures, such as bending antenna bracket, are both presented; the integration design of high isolation of ultra broadband MIMO antenna is realized on the plate with the volume of 100 × 52 × 0.8 mm3; antenna working bands are 698 MHz~960 MHz and 1710 MHz~2700 MHz; in the whole spectrum, the 10 dB of port isolation can be basically achieved; in low frequency band, the isolation degree of antenna port can reach 12 dB.

Current phase control test based on real-time measurement of impedance matrix of ICRF antennas

Energy Technology Data Exchange (ETDEWEB)

Saito, K., E-mail: saito@nifs.ac.jp [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Kumazawa, R.; Seki, T.; Kasahara, H.; Yokota, M.; Nomura, G.; Shimpo, F.; Mutoh, T. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

2011-10-15

New ion cyclotron range of frequencies (ICRF) antennas have just been installed in the large helical device (LHD). These side-by-side ICRF antennas are symmetrical and designed to launch fast waves with various wave numbers parallel to the magnetic field line. The wave number can be controlled by changing the current phase on the straps; however, the mutual coupling between antennas changes antenna impedances, even if the plasma parameters are constant, leading to an increase in the reflected power. In addition to the current phase control, impedance matching devices must be tuned for the protection of tetrode tubes and efficient power injection. For this purpose, the impedance matrix of ICRF antennas must be determined, and it can be deduced from the forward and reflected waves at the outlet of the power amplifier by assuming geometric symmetry and reciprocity of the antennas. Using half-scale antennas, we successfully demonstrated simultaneous impedance matching and current phase control.

Zeroth order resonator (ZOR) based RFID antenna design

Science.gov (United States)

Masud, Muhammad Mubeen

Meander-line and multi-layer antennas have been used extensively to design compact UHF radio frequency identification (RFID) tags; however the overall size reduction of meander-line antennas is limited by the amount of parasitic inductance that can be introduced by each meander-line segment, and multi-layer antennas can be too costly. In this study, a new compact antenna topology for passive UHF RFID tags based on zeroth order resonant (ZOR) design techniques is presented. The antenna consists of lossy coplanar conductors and either inter-connected inter-digital capacitor (IDC) or shunt inductor unit-cells with a ZOR frequency near the operating frequency of the antenna. Setting the ZOR frequency near the operating frequency is a key component in the design process because the unit-cells chosen for the design are inductive at the operating frequency. This makes the unit-cells very useful for antenna miniaturization. These new designs in this work have several benefits: the coplanar layout can be printed on a single layer, matching inductive loops that reduce antenna efficiency are not required and ZOR analysis can be used for the design. Finally, for validation, prototype antennas are designed, fabricated and tested.

Construction of a resonant loop with the ICRF antenna for KSTAR

International Nuclear Information System (INIS)

Bae, Young Dug; Jeong, Sung Un; Yoon, Jae Sung; Hong, Bong Geon

2003-01-01

The antenna of the KSTAR ICRF heating system consists of four current straps, each of which is grounded at the center, and has two coaxial ports, one at each end. The top and bottom ports of each strap are fed by one transmitter. The two ports are connected at tee connector to form a resonant loop, and the coaxial feed line from the transmitter is connected to the tee. One resonant loop with the proto-type antenna is built at the RF test stand in KAERI. It is composed with one current strap, one tee connector and two arms connecting them. Each arm consists of a 6-inch vacuum transmission line, a vacuum feed through, a part of pressurized 9-inch coaxial line, and an adjustable phase shifter to cover wide frequency range of 25-60 MHz. Total electrical length is changeable from 45 to 51 m. Many voltage probes and directional couplers are installed to measure RF voltage of the standing wave, power flow and phase difference. Resonant and matching conditions are investigated for various frequencies

Analysis of the phase control of the ITER ICRH antenna array. Influence on the load resilience and radiated power spectrum

Energy Technology Data Exchange (ETDEWEB)

Messiaen, A., E-mail: a.messiaen@fz-juelich.de; Ongena, J.; Vervier, M. [Laboratory for Plasma Physics, ERM-KMS, TEC partner, Cycle, B1000-Brussels (Belgium); Swain, D. [US ITER Team, ORNL (United States)

2015-12-10

The paper analyses how the phasing of the ITER ICRH 24 strap array evolves from the power sources up to the strap currents of the antenna. The study of the phasing control and coherence through the feeding circuits with prematching and automatic matching and decoupling network is made by modeling starting from the TOPICA matrix of the antenna array for a low coupling plasma profile and for current drive phasing (worst case for mutual coupling effects). The main results of the analysis are: (i) the strap current amplitude is well controlled by the antinode V{sub max} amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of V{sub max} of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is ±20°, (iv) the effect on load resilience remains well below the maximum affordable VSWR of the generators, (v) the effect on the radiated power spectrum versus k{sub //} computed by means of the coupling code ANTITER II remains small for the considered cases.

Antenna design for mobile devices

CERN Document Server

Zhang, Zhijun

2017-01-01

- Integrates state-of-the-art technologies with a special section for step-by-step antenna design - Features up-to-date bio-safety and electromagnetic compatibility regulation compliance and latest standards - Newly updated with MIMO antenna design, measurements and requirements - Accessible to readers of many levels, from introductory to specialist - Written by a practicing expert who has hired and trained numerous engineers

Microstrip Antenna Design for Femtocell Coverage Optimization

Directory of Open Access Journals (Sweden)

Afaz Uddin Ahmed

2014-01-01

Full Text Available A mircostrip antenna is designed for multielement antenna coverage optimization in femtocell network. Interference is the foremost concern for the cellular operator in vast commercial deployments of femtocell. Many techniques in physical, data link and network-layer are analysed and developed to settle down the interference issues. A multielement technique with self-configuration features is analyzed here for coverage optimization of femtocell. It also focuses on the execution of microstrip antenna for multielement configuration. The antenna is designed for LTE Band 7 by using standard FR4 dielectric substrate. The performance of the proposed antenna in the femtocell application is discussed along with results.

Influence of the plasma profile and the antenna geometry on the matching and current distribution control of the ITER ICRF antenna array. Optimization of the decoupling-matching system

Energy Technology Data Exchange (ETDEWEB)

Messiaen, A., E-mail: a.messiaen@fz-juelich.de [LPP-ERM/KMS, EURATOM-Belgian State Association, TEC Partner, CYCLE, B-1000 Brussels (Belgium); Swain, D. [US ITER Team, ORNL (United States); Vervier, M.; Dumortier, P.; Durodié, F.; Grine, D. [LPP-ERM/KMS, EURATOM-Belgian State Association, TEC Partner, CYCLE, B-1000 Brussels (Belgium)

2013-10-15

Highlights: ► Analysis of the matching-decoupling system of the ICRF antenna array of ITER. ► Control of the array phasing by the decouplers for the same power of power sources. ► Computation for the 2012 design status of the antenna plug. ► 7 decouplers needed but 10 can be used to decrease the ratings of components. ► Effects of plasma profile and antenna geometry. -- Abstract: The eight triplets of straps of the ITER ICRF antenna array are fed through 8 matching circuits and 4 hybrids to ensure load resilience. Decouplers are used to mitigate the effects of triplet mutual coupling. They also control the array phasing. The electrical constraints on the decouplers for different layouts with heating (H) or current drive (CD) phasing are compared starting from the TOPICA matrix computed for the last antenna plug design and the reference (most pessimistic) plasma profile “2010low” provided by IO. It is shown that this last profile provides a significant decrease of plasma coupling and increase of mutual coupling with respect to the previous reference profile “Sc2short17”. This results in a larger range of decoupler reactance X{sub dec} and voltage V{sub Xdec} needed. This range can be reduced when using 10 decouplers instead of the 7 needed for the same forward power P{sub Gk+} of the 4 power sources. For H phasing only 4 decouplers could be used but with different P{sub Gk+} (P{sub Gk+} ratio up to 1.5–2.5). For CD phasing and same plasma profile the power capability P{sub tot} is increased by 25% with a decoupler layout allowing much smaller poloidal phasing than the 90° provided by the hybrids. A decrease of the distance antenna-plasma profile reduces the normalized decoupler voltage V{sub Xdec}/√P{sub tot} with no significant change of the X{sub dec} range. The recess of the vertical septa between the strap boxes increases the plasma coupling but has the drawback of also increasing the mutual coupling between triplets: the needed range of X

Design of cost effective antennas for instrumentation radars

CSIR Research Space (South Africa)

Botha, L

2012-09-01

Full Text Available The cost of antennas for instrumentation radars are determined by the development cost. By re-use of the reflector system cost effective antennas can be designed. The factors governing the design of such antennas are described here....

Design of reconfigurable antennas using graph models

CERN Document Server

Costantine, Joseph; Christodoulou, Christos G; Christodoulou, Christos G

2013-01-01

This lecture discusses the use of graph models to represent reconfigurable antennas. The rise of antennas that adapt to their environment and change their operation based on the user's request hasn't been met with clear design guidelines. There is a need to propose some rules for the optimization of any reconfigurable antenna design and performance. Since reconfigurable antennas are seen as a collection of self-organizing parts, graph models can be introduced to relate each possible topology to a corresponding electromagnetic performance in terms of achieving a characteristic frequency of oper

Design methodology of single-feed compact near-isotropic antenna design

KAUST Repository

Su, Zhen

2017-06-07

The abundance of mobile wireless devices is giving rise to a new paradigm known as Internet of Things. In this paradigm, wireless devices will be everywhere and communicating with each other. Since they will be oriented randomly in the environment, they should be able to communicate equally in all directions in order to have stable communication link. Hence, compact near isotropic antennas are required, which can enable orientation insensitive communication. In this paper, we propose a simple design methodology to design a compact near-isotropic wire antenna based on equal vector potentials. As a proof of concept, a quarter wavelength monopole antennas has been designed that is wrapped on a 3D-printed box keeping the vector potentials in three orthogonal different directions equal. By optimizing the dimension of the antenna arms, a nearly isotropic radiation pattern is thus achieved. The results show that the antenna has a maximum gain of 2.2dBi at 900 MHz with gain derivation of 9.4dB.

On-chip antenna: Practical design and characterization considerations

KAUST Repository

Shamim, Atif; Salama, Khaled N.; Sedky, S.; Soliman, E. A.

2012-01-01

This paper highlights the challenges of an emergent field, namely, on-chip antenna design. Consistent with the RF System-on-Chip (SoC) concept, co-design strategy for circuits and on-chip antennas is described. A number of design and layout issues, arising from the highly integrated nature of this kind of systems, are discussed. The characterization difficulties related to on-chip antennas radiation properties are also highlighted. Finally, a novel on-wafer test fixture is proposed to measure the gain and radiation pattern of the on-chip antennas in the anechoic chamber.

On-chip antenna: Practical design and characterization considerations

KAUST Repository

Shamim, Atif

2012-07-28

This paper highlights the challenges of an emergent field, namely, on-chip antenna design. Consistent with the RF System-on-Chip (SoC) concept, co-design strategy for circuits and on-chip antennas is described. A number of design and layout issues, arising from the highly integrated nature of this kind of systems, are discussed. The characterization difficulties related to on-chip antennas radiation properties are also highlighted. Finally, a novel on-wafer test fixture is proposed to measure the gain and radiation pattern of the on-chip antennas in the anechoic chamber.

Design of LTCC Based Fractal Antenna

KAUST Repository

AdbulGhaffar, Farhan

2010-01-01

The thesis presents a Sierpinski Carpet fractal antenna array designed at 24 GHz for automotive radar applications. Miniaturized, high performance and low cost antennas are required for this application. To meet these specifications a fractal array

Material and electromagnetic properties of Faraday shields for ion cyclotron heating antennas

International Nuclear Information System (INIS)

Hoffman, D.J.; Baity, F.W.; Becraft, W.R.; Caughman, J.B.O.; Tsai, C.C.

1985-01-01

The Faraday shields for ion cyclotron antennas must transmit magnetic waves and absorb little RF power. To investigate these properties, we have constructed 27 Faraday shields in many configurations, including chevrons, tubes, straps, concentric rings, various layered shields, conventionally leafed straps, and replicas of the Faraday shields for ASDEX, the Joint European Torus (JET), TEXTOR, and Alcator-C. We have measured the magnetic flux and observed loading at various operating resistances by using dielectric sheets or magnetic-coupled loads. Each Faraday shield effects a net change in the characteristic inductance of the antenna, resulting in a reduction of wave coupling. However, the load experienced by the antenna is not always reduced because the Faraday shield itself acts as a load. We differentiate between these effects experimentally. The net result of the study is that the Faraday shields now in use cost up to a factor of 50% of coupling. This, of course, reduces the power handling capability by 50% as well. However, configurations exist that are easily cooled and result in a reduction of less than 5% in loading

Material and electromagnetic properties of Faraday shields for ion cyclotron heating antennas

International Nuclear Information System (INIS)

Hoffman, D.J.; Becraft, W.R.; Baity, F.W.; Caughman, J.B.O.; Tsai, C.C.

1985-01-01

The Faraday shields for ion cyclotron antennas must transmit magnetic waves and adsorb little rf power. To investigate these properties, we have constructed 27 Faraday shields in many configurations, including chevrons, tubes, straps, concentric rings, various layered shields, conventionally leafed straps, and replicas of the Faraday shields for ASDEX, the Joint European Torus (JET), TEXTOR, and Alcator-C. We have measured the magnetic flux and observed loading at various operating resistances by using dielectric sheets or magnetic-coupled loads. Each Faraday shield effects a net change in the characteristic inductance of the antenna, resulting in a reduction of wave coupling. However, the load experienced by the antenna is not always reduced because the Faraday shield itself acts as a load. We differentiate between these effects experimentally. The net result of the study is that the Faraday shields now in use cost up to a factor of 50% of coupling. This, of course, reduces the power handling capability by 50% as well. However, configurations exist that are easily cooled and result in a reduction of less than 5% in loading

Outer grid strap protruding spring repair apparatus

International Nuclear Information System (INIS)

Widener, W.H.

1987-01-01

This patent describes a nuclear fuel assembly grid spring repair apparatus for repairing a spring formed on an outer strap of a fuel assembly grid and having a portion protruding outwardly beyond the strap, the apparatus comprising: (a) a support frame defining an opening and having means defining a guide channel extending along the opening in a first direction; (b) means mounted on the frame and being adjustable for attaching the frame to the outer strap of the support grid so that the frame opening is aligned with the outwardly protruding spring on the outer strap; (c) an outer slide having a passageway defined therethrough and being mounted in the guide channel for reciprocable movement along the frame opening in the first direction for aligning the passageway with the outwardly protruding portion of the spring on the outer strap. The outer slide also has means defining a guide way extending along the passageway in a second direction generally orthogonal to the first direction; (d) a spring reset mechanism being operable for resetting the protruding spring to a nonprotruding position relative to the outer strap when the mechanism is aligned with the protruding portion of the spring; and (e) an inner slide supporting the spring reset mechanism and being mounted to the guide way for reciprocable movement along the passageway of the outer slide in the second direction for aligning the spring reset mechanism with the protruding portion of the spring on the outer strap

Plasma enhanced RF power deposition on ICRF antennas in Tore Supra

International Nuclear Information System (INIS)

Goulding, R.H.; Harris, J.H.; Carter, M.D.; Hoffman, D.J.; Hogan, J.T.; Ryan, P.M.; Beaumont, B.; Bremond, S.; Hutter, T.

1997-01-01

The dual-strap Tore Supra ICRF antennas have been very successful in coupling high power fluxes > 16 MW/m2 to the plasma. In many cases it has been found that the power is limited not by the voltages and currents that can be sustained on antenna components, but rather by localized increases in antenna surface temperatures which are correlated with increased impurity levels. Hot spots have been observed using an IR imaging system with peak temperatures as high as 1,100 C after 2 s, and as little as 1.5 MW power coupled from a single launcher. The maximum temperature observed is highly dependent on antenna phasing, and is lowest with dipole (π) phasing of the relative antenna currents. Both toroidal and poloidal asymmetries in hot spot distribution have been observed, and interestingly, the toroidal asymmetry has been found to vary when the phase is changed from +π/2 to -π/2. Significant differences in the temperature profiles have been seen on the two types of Faraday shield in use, which appears to be related to the fact that one type has a recessed center septum between straps while the other does not. In some cases, the peak temperature has been observed to increase as the antenna/plasma gap is increased, while the peak remains in the same location. This behavior suggests that voltages generated by currents flowing in the Faraday shield structure itself may play a role in generating potentials responsible for the hot spots, in addition to rf fields in the plasma. In this paper data on antenna surface heating and loading data as a function of plasma density, antenna/plasma gap, and phasing will be presented. Calculations from the RANT3D electromagnetic code together with bench measurements of electric fields near the antenna surface will also be shown

Design options for an ITER ion cyclotron system

International Nuclear Information System (INIS)

Swain, D.W.; Baity, F.W.; Bigelow, T.S.; Ryan, P.M.; Goulding, R.H.; Carter, M.D.; Stallings, D.C.; Batchelor, D.B.; Hoffman, D.J.

1995-01-01

Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10--20 cm. Designs of a conventional strap launcher and a folded waveguide launcher than can meet the new requirements are presented

Antenna Design Exploiting the Duplex Isolation

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Pedersen, Gert Frølund

2013-01-01

A novel design addressing the antenna bandwidth issue for future communication standards on handsets is presented. It consists of a tunableantenna- pair for operation with a tunable front-end. The antennas are narrow-band and frequency-reconfigurable. This Letter focuses on the low communication ...

21 CFR 868.5560 - Gas mask head strap.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas mask head strap. 868.5560 Section 868.5560...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5560 Gas mask head strap. (a) Identification. A gas mask head strap is a device used to hold an anesthetic gas mask in position on a patient's...

STRAP-2, Stress Analysis of Structure with Static Loading by Finite Elements Method. STRAP-D, Stress Analysis of Structure with Time-Dependent Loading by Finite Elements Method

International Nuclear Information System (INIS)

Dearien, J.A.; Uldrich, E.D.

1975-01-01

1 - Description of problem or function: The code STRAP (Structural Analysis Package) was developed to analyze the response of structural systems to static and dynamic loading conditions. STRAP-S solves for the displacements and member forces of structural systems under static loads and temperature gradients. STRAP-D will solve numerically a given structural dynamics problem. 2 - Method of solution: STRAP-S generates the stiffness matrix of a structure by the finite element method and solves the resulting equations for structural displacements and member forces. STRAP-D generates the stiffness matrix, solves for eigenvalues and eigenvectors, uncouples and solves the series of second-order ordinary differential equations, and then calculates and plots the requested member forces. 3 - Restrictions on the complexity of the problem: STRAP-S maxima: 250 degrees of freedom, 100 members; STRAP-D maxima: 100 degrees of freedom, 80 time-steps in the forcing function input

Plasma-surface interactions with ICRF antennas and lower hybrid grills in Tore Supra

International Nuclear Information System (INIS)

Harris, J.H.; Hutter, T.; Hogan, J.T.; Basiuk, V.; Beaumont, B.; Becoulet, A.; Bremond, S.; Carter, M.D.; Goniche, M.; Goulding, R.H.; Guilhem, D.; Haste, G.R.; Hoffman, D.J.; Litaudon, X.; Nguyen, F.

1997-01-01

The edge plasma interactions of the actively cooled radio-frequency heating launchers in Tore Supra ion-cyclotron range of frequencies (ICRF) antennas and lower-hybrid (LH) grills are studied using infrared video imaging. On the two-strap ICRF antennas, operated in fast-wave electron heating or current drive mode, hot spots with temperatures of 500-900 C are observed by the end of 2 s power pulses of 2 MW per antenna. The steady-state temperature distribution is determined principally by the relative phase of the two antenna straps: dipole (heating) phasing results in significantly less antenna heating than does 90 (current drive) phasing. Transient heat fluxes of 1-20 MW/m 2 are measured on the lateral protection bumpers at ICRF turn-on; these fluxes are primarily a function of plasma and radio frequency (rf) control. The remarkable feature of the lower hybrid edge interaction is the production of beams of heat flux in front of the grills; these beams propagate along the helical magnetic field lines and can deliver fluxes of 5-10 MW/m 2 over areas of several cm 2 to plasma-facing components. Both the ICRF and LH phenomena appear to result from the acceleration of particles by the near fields of the launchers. Modeling of the heat flux deposition on components and its relation to sputtering processes is presented. (orig.)

C-STrap Sample Preparation Method--In-Situ Cysteinyl Peptide Capture for Bottom-Up Proteomics Analysis in the STrap Format.

Directory of Open Access Journals (Sweden)

Alexandre Zougman

Full Text Available Recently we introduced the concept of Suspension Trapping (STrap for bottom-up proteomics sample processing that is based upon SDS-mediated protein extraction, swift detergent removal and rapid reactor-type protein digestion in a quartz depth filter trap. As the depth filter surface is made of silica, it is readily modifiable with various functional groups using the silane coupling chemistries. Thus, during the digest, peptides possessing specific features could be targeted for enrichment by the functionalized depth filter material while non-targeted peptides could be collected as an unbound distinct fraction after the digest. In the example presented here the quartz depth filter surface is functionalized with the pyridyldithiol group therefore enabling reversible in-situ capture of the cysteine-containing peptides generated during the STrap-based digest. The described C-STrap method retains all advantages of the original STrap methodology and provides robust foundation for the conception of the targeted in-situ peptide fractionation in the STrap format for bottom-up proteomics. The presented data support the method's use in qualitative and semi-quantitative proteomics experiments.

C-STrap Sample Preparation Method--In-Situ Cysteinyl Peptide Capture for Bottom-Up Proteomics Analysis in the STrap Format.

Science.gov (United States)

Zougman, Alexandre; Banks, Rosamonde E

2015-01-01

Recently we introduced the concept of Suspension Trapping (STrap) for bottom-up proteomics sample processing that is based upon SDS-mediated protein extraction, swift detergent removal and rapid reactor-type protein digestion in a quartz depth filter trap. As the depth filter surface is made of silica, it is readily modifiable with various functional groups using the silane coupling chemistries. Thus, during the digest, peptides possessing specific features could be targeted for enrichment by the functionalized depth filter material while non-targeted peptides could be collected as an unbound distinct fraction after the digest. In the example presented here the quartz depth filter surface is functionalized with the pyridyldithiol group therefore enabling reversible in-situ capture of the cysteine-containing peptides generated during the STrap-based digest. The described C-STrap method retains all advantages of the original STrap methodology and provides robust foundation for the conception of the targeted in-situ peptide fractionation in the STrap format for bottom-up proteomics. The presented data support the method's use in qualitative and semi-quantitative proteomics experiments.

ORNL compact loop antenna design for TFTR and Tore Supra

International Nuclear Information System (INIS)

Taylor, D.J.; Baity, F.W.; Bryan, W.E.; Hoffman, D.J.; McIlwain, R.L.; Ray, J.M.

1987-01-01

The goal supplemental ion cyclotron resonance heating (ICRH) of fusion plasma is to deliver power at high efficiencies deep within the plasma. The technology for fast-wave ICRH has reached the point of requiring ''proof-of-performance'' demonstration of specific antenna configurations of specific antenna configurations and their mechanical adequacy for operating in a fusion environment. Oak Ridge National Laboratory (ORNL) has developed the compact loop antenna concept based on a resonant double loop (RDL) configuration for use in both Tokamak Fusion Test Reactor (TFTR) and the Tore Supra ICRH programs. A description and a comparison of the technologies developed in the two designs are presented. The electrical circuit and the mechanical philosophy employed are the same for both antennas, but different operating environments result in substantial differences in the design of specific components. The ORNL TFTR antenna is designed to deliver 4 MW over a 2-s pulse, and the ORNL Tore Supra antenna is designed for 4 MW and essentially steady-state conditions. The TFTR design embodies the first operations compact RDL antenna, and the Tore Supra antenna extends the technology to an operational duty cycle consistent with reactor-relevant applications. 7 refs., 5 figs

Design of a C- Band Circular Polarization Microstrip Antenna

Science.gov (United States)

Yohandri; Jumiah, Yusna; Tetuko Sri Sumantyo, Josaphat

2018-04-01

The development of circularly polarized microstrip antenna is an interesting topic in current research, due to its superiority in various applications. In this work, the design of a circular polarization antenna that will be operated in the C-band range will be described. The developed antenna is intended to be used for Synthetic Aperture Radar (SAR) applications. Through this application, various targets or areas on the surface of the earth, such as buildings, soil and land can be observed. To get the ideal antenna characteristic, in this research the various parameters in antenna design will be simulated. A software CST Studio will be operated in this simulation. Based on the simulation results, the optimum parameters are obtained in term of reflection coefficient, VSWR, axial ratio, and gain. The reflection coefficient of the antenna (S11) is obtained at -19.75 dB and VSWR of 1.23. Meanwhile, the axial ratio and gain of the antenna were obtained at 2.66 dB and 2.1 dBi, respectively. Based on this simulated results, antenna design is potential to be developed and fabricated for SAR sensor applications.

Does the Powers™ strap influence the lower limb biomechanics during running?

Science.gov (United States)

Greuel, Henrike; Herrington, Lee; Liu, Anmin; Jones, Richard K

2017-09-01

Previous research has reported a prevalence of running related injuries in 25.9% to 72% of all runners. A greater hip internal rotation and adduction during the stance phase in running has been associated with many running related injuries, such as patellofemoral pain. Researchers in the USA designed a treatment device 'the Powers™ strap' to facilitate an external rotation of the femur and to thereby control abnormal hip and knee motion during leisure and sport activities. However, to date no literature exists to demonstrate whether the Powers™ strap is able to reduce hip internal rotation during running. 22 healthy participants, 11 males and 11 females (age: 27.45±4.43 years, height: 1.73±0.06m, mass: 66.77±9.24kg) were asked to run on a 22m track under two conditions: without and with the Powers™ strap. Three-dimensional motion analysis was conducted using ten Qualisys OQUS 7 cameras (Qualisys AB, Sweden) and force data was captured with three AMTI force plates (BP600900, Advanced Mechanical Technology, Inc.USA). Paired sample t-tests were performed at the 95% confidence interval on all lower limb kinematic and kinetic data. The Powers™ strap significantly reduced hip and knee internal rotation throughout the stance phase of running. These results showed that the Powers™ strap has the potential to influence hip motion during running related activities, in doing so this might be beneficial for patients with lower limb injuries. Future research should investigate the influence of the Powers™ strap in subjects who suffer from running related injuries, such as patellofemoral pain. Copyright © 2017 Elsevier B.V. All rights reserved.

Ion cyclotron system design for KSTAR tokamak

International Nuclear Information System (INIS)

Hong, B. G.; Hwang, C. K.; Jeong, S. H.; Yoony, J. S.; Bae, Y. D.; Kwak, J. G.; Ju, M. H.

1998-05-01

The KSTAR (Korean Superconducting Tokamak Advanced Research) tokamak (R=1.8 m, a=0.5 m, k=2, b=3.5T, I=2MA, t=300 s) is being constructed to do long-pulse, high-b, advanced-operating-mode fusion physics experiments. The ion cyclotron (IC) system (in conjunction with an 8-MW neutral beam and a 1.5-MW lower hybrid system) will provide heating and current drive capability for the machine. The IC system will deliver 6 MW of RF power to the plasma in the 25 to 60 MHz frequency range, using a single four-strap antenna mounted in a midplane port. It will be used for ion heating, fast-wave current drive (FWCD), and mode-conversion current drive (MCCD). The phasing between current straps in the antenna will be adjustable quickly during operation to provide the capability of changing the current-drive efficiency. This report describes the design of the IC system hardware: the electrical characteristics of the antenna and the matching system, the requirements on the power sources, and electrical analyses of the launcher. (author). 7 refs., 2 tabs., 40 figs

Ion cyclotron system design for KSTAR tokamak

Energy Technology Data Exchange (ETDEWEB)

Hong, B. G.; Hwang, C. K.; Jeong, S. H.; Yoony, J. S.; Bae, Y. D.; Kwak, J. G.; Ju, M. H

1998-05-01

The KSTAR (Korean Superconducting Tokamak Advanced Research) tokamak (R=1.8 m, a=0.5 m, k=2, b=3.5T, I=2MA, t=300 s) is being constructed to do long-pulse, high-b, advanced-operating-mode fusion physics experiments. The ion cyclotron (IC) system (in conjunction with an 8-MW neutral beam and a 1.5-MW lower hybrid system) will provide heating and current drive capability for the machine. The IC system will deliver 6 MW of RF power to the plasma in the 25 to 60 MHz frequency range, using a single four-strap antenna mounted in a midplane port. It will be used for ion heating, fast-wave current drive (FWCD), and mode-conversion current drive (MCCD). The phasing between current straps in the antenna will be adjustable quickly during operation to provide the capability of changing the current-drive efficiency. This report describes the design of the IC system hardware: the electrical characteristics of the antenna and the matching system, the requirements on the power sources, and electrical analyses of the launcher. (author). 7 refs., 2 tabs., 40 figs.

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.

Design and Fabrication of a Reconfigurable MEMS-Based Antenna

KAUST Repository

Martinez, Miguel Angel Galicia

2011-06-22

This thesis presents the design and fabrication of a customized in house Micro-Electro-Mechanical-Systems (MEMS) process based on-chip antenna that is both frequency and polarization reconfigurable. It is designed to work at both 60 GHz and 77 GHz through MEMS switches. This antenna can also work in both horizontal and vertical linear polarizations by utilizing a moveable plate. The design is intended for Wireless Personal Area Networks (WPAN) and automotive radar applications. Typical on-chip antennas are inefficient and difficult to reconfigure. Therefore, the focus of this work is to develop an efficient on-chip antenna solution, which is reconfigurable in frequency and in polarization. A fractal bowtie antenna is employed for this thesis, which achieves frequency reconfigurability through MEMS switches. The design is simulated in industry standard Electromagnetic (EM) simulator Ansoft HFSS. A novel concept for horizontal to vertical linear polarization agility is introduced which incorporates a moveable polymer plate. For this work, a microprobe is used to move the plate from the horizontal to vertical position. For testing purposes, a novel mechanism has been designed in order to feed the antenna with RF-probes in both horizontal and vertical positions. A simulated gain of approximately 0 dB is achieved at both target frequencies (60 and 77 GHz), in both horizontal and vertical positions. In all the cases mentioned above (both frequencies and positions), the antenna is well matched (< -10 dB) to the 50 Ω system impedance. Similarly, the radiation nulls are successfully shifted by changing the position of the antenna from horizontal to vertical. The complete design and fabrication of the reconfigurable MEMS antenna has been done at KAUST facilities. Some challenges have been encountered during its realization due to the immaturity of the customized MEMS fabrication process. Nonetheless, a first fabrication attempt has highlighted such shortcomings. According

Nuclear fuel grid outer strap

International Nuclear Information System (INIS)

Duncan, R.; Craver, J.E.

1989-01-01

This patent describes a nuclear reactor fuel assembly grid. It comprises a first outer grip strap segment end. The first end having a first tab arranged in substantially the same plane as the plane defined by the first end; a second outer grip strap end. The second end having a second slot arranged in substantially the same plane as the plane defined by the second end, with the tab being substantially disposed in the slot, defining a socket therebetween; and a fort tine interposed substantially perpendicularly in the socket

Dual-Band Split-Ring Antenna Design for WLAN Applications

OpenAIRE

BAŞARAN, S. Cumhur; ERDEMLİ, Yunus E.

2014-01-01

A dual-band microstrip antenna based on split-ring elements is introduced for WLAN (2.4/5.2 GHz) applications. The proposed split-ring antenna (SRA) has a compact novel design which provides about 2% impedance-bandwidth without a need for additional matching network. Analysis and design of the proposed microstrip antenna is carried out by means of full-wave simulators based on the finite-element method.

Comparative Study of Antenna Designs for RF Energy Harvesting

Directory of Open Access Journals (Sweden)

Sika Shrestha

2013-01-01

Full Text Available In the last few years, several antenna designs of rectenna that meet various objectives have been proposed for use in RF energy harvesting. Among various antennas, microstrip patch antennas are widely used because of their low profile, light weight, and planar structure. Conventional patch antennas are rectangular or circular in shape, but variations in their basic design are made for different purposes. This paper begins with an explanation and discussion of different designs, put forward with an aim of miniaturization, harmonic rejection, and reconfigurability. Finally, microstrip patch structured rectennas are evaluated and compared with an emphasis on the various methods adopted to obtain a compact rectenna, harmonic rejection functionality, and frequency and polarization selectivity.

New Flexible Medical Compact Antenna: Design and Analysis

Directory of Open Access Journals (Sweden)

Yann Mahe

2012-01-01

Full Text Available Some results on embedded antennas for medical wireless communication systems are presented. Medical telemetry can advantageously assist medical diagnostics. For example, you can better locate a diseased area by monitoring temperature inside the human body. In order to establish efficient wireless links in such an environment, a special attention should be paid to the antenna design. It is required to be of a low profile, very small regardless of the working frequency—434 MHz in the ISM band, safe, and cost effective. Design of the as-considered antenna is proposed based on a simple model. The approach has been demonstrated for a compact flexible antenna with a factor of 10 with respect to the half-wave antenna, rolling up inside an ingestible pill. Measured and calculated impedance behaviour and radiation characteristics of the modified patch are determined. Excellent agreement was found between experiment and theory.

Design and control of phased ICRF antenna arrays

International Nuclear Information System (INIS)

Goulding, R.H.; Baity, F.W.; Hoffman, D.J.

1993-01-01

Phased antenna arrays operating in the ion cyclotron range of frequencies (ICRF) are used to produce highly directional wave spectra, primarily for use in current drive experiments. RF current drive using phased antennas has been demonstrated in both the JET and DIII-D tokamaks, and both devices are planning to operate new four-element arrays beginning early next year. Features of antenna design that are relevant to phased operation and production of directional spectra are reviewed. Recent advances in the design of the feed circuits and the related control systems for these arrays should substantially improve their performance, by reducing the coupling seen by the matching networks and rf power supplies caused by the mutual impedance of the array elements. The feed circuit designs for the DIII-D and JET phased antenna arrays are compared. The two configurations differ significantly due to the fact that one power amplifier is used for the entire array in the former case, and one per element in the latter. The JET system uses automatic feedback control of matching, phase and amplitude of antenna currents, and the transmitter power balance. The design of this system is discussed, and a time dependent model used to predict its behavior is described

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.

Design of silicon-based fractal antennas

KAUST Repository

Ghaffar, Farhan A.

2012-11-20

This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

Design of silicon-based fractal antennas

KAUST Repository

Ghaffar, Farhan A.; Shamim, Atif

2012-01-01

This article presents Sierpinski carpet fractal antennas implemented in conventional low resistivity (Ï =10 Ω cm) as well as high resistivity (Ï =1500 Ω cm) silicon mediums. The fractal antenna is 36% smaller as compared with a typical patch antenna at 24 GHz and provides 13% bandwidth on high resistivity silicon, suitable for high data rate applications. For the first time, an on-chip fractal antenna array is demonstrated in this work which provides double the gain of a single fractal element as well as enhanced bandwidth. A custom test fixture is utilized to measure the radiation pattern and gain of these probe-fed antennas. In addition to gain and impedance characterization, measurements have also been made to study intrachip communication through these antennas. The comparison between the low resistivity and high resistivity antennas indicate that the former is not a suitable medium for array implementation and is only suitable for short range communication whereas the latter is appropriate for short and medium range wireless communication. The design is well-suited for compact, high data rate System-on-Chip (SoC) applications as well as for intrachip communication such as wireless global clock distribution in synchronous systems. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:180-186, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27245 Copyright © 2012 Wiley Periodicals, Inc.

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.

Wearable Inset-Fed FR4 Microstrip Patch Antenna Design

Science.gov (United States)

Zaini, S. R. Mohd; Rani, K. N. Abdul

2018-03-01

This project proposes the design of a wireless body area network (WBAN) microstrip patch antenna covered by the jeans fabric as the outer layer operating at the center frequency, fc of 2.40 GHz. Precisely, the microstrip patch antenna with the inset-fed edge technique is designed and simulated systematically by using the Keysight Advanced Design System (ADS) software where the FR4 board with the dielectric constant, ɛr of 4.70, dissipation factor or loss tangent, tan δ of 0.02 and height, h of 1.60 mm is the chosen dielectric substrate. The wearable microstrip patch antenna design is then fabricated using the FR4 printed circuit board (PCB) material, hidden inside the jeans fabric, and attached to clothing, such as a jacket accordingly. Simulation and fabrication measurement results show that the designed microstrip patch antenna characteristics can be applied significantly within the industrial, scientific, and medical (ISM) radio band, which is at fc = 2.40 GHz.

Characterization and performance of a field aligned ion cyclotron range of frequency antenna in Alcator C-Moda)

Science.gov (United States)

Wukitch, S. J.; Garrett, M. L.; Ochoukov, R.; Terry, J. L.; Hubbard, A.; Labombard, B.; Lau, C.; Lin, Y.; Lipschultz, B.; Miller, D.; Reinke, M. L.; Whyte, D.; Alcator C-Mod Team

2013-05-01

Ion cyclotron range of frequency (ICRF) heating is expected to provide auxiliary heating for ITER and future fusion reactors where high Z metallic plasma facing components (PFCs) are being considered. Impurity contamination linked to ICRF antenna operation remains a major challenge particularly for devices with high Z metallic PFCs. Here, we report on an experimental investigation to test whether a field aligned (FA) antenna can reduce impurity contamination and impurity sources. We compare the modification of the scrape of layer (SOL) plasma potential of the FA antenna to a conventional, toroidally aligned (TA) antenna, in order to explore the underlying physics governing impurity contamination linked to ICRF heating. The FA antenna is a 4-strap ICRF antenna where the current straps and antenna enclosure sides are perpendicular to the total magnetic field while the Faraday screen rods are parallel to the total magnetic field. In principle, alignment with respect to the total magnetic field minimizes integrated E|| (electric field along a magnetic field line) via symmetry. A finite element method RF antenna model coupled to a cold plasma model verifies that the integrated E|| should be reduced for all antenna phases. Monopole phasing in particular is expected to have the lowest integrated E||. Consistent with expectations, we observed that the impurity contamination and impurity source at the FA antenna are reduced compared to the TA antenna. In both L and H-mode discharges, the radiated power is 20%-30% lower for a FA-antenna heated discharge than a discharge heated with the TA-antennas. However, inconsistent with expectations, we observe RF induced plasma potentials (via gas-puff imaging and emissive probes to be nearly identical for FA and TA antennas when operated in dipole phasing). Moreover, the highest levels of RF-induced plasma potentials are observed using monopole phasing with the FA antenna. Thus, while impurity contamination and sources are indeed

Innovative Concrete Repairing Technique Using Post Tensioning Steel Straps

Directory of Open Access Journals (Sweden)

Ma Chau-Khun

2017-01-01

Full Text Available In this paper, innovative technique using low-cost recycled steel straps confinement to repair load-induced damaged high-strength concrete (HSC columns were studied. This paper explains the effects of repairing technique using post tensioning steel straps. A series of experimental test was carried out to investigate the stress-strain relationships of such concrete. A total of 6 HSC columns were compressed 50% of their ultimate strength, then repaired by using steel straps. The proposed repairing technique significantly improved the performance of damaged concrete columns, in both strength and ductility. It was evidenced from this study that the steel strapping confining technique is effective in repairing of damaged HSC columns but ensured reasonable operating costs.

Designing a fractal antenna of 2400 MHz

International Nuclear Information System (INIS)

Miranda Hamburger, Fabio

2012-01-01

The design of a fractal antenna with 2400 MHz of frequency has been studied. The fractal used is described by Waclaw Spierpi.ski. The initial figure, also known as seed, is divided using equilateral triangles with the aim of obtaining a perimeter similar to a meaningful portion of wave length. The use of λ to establish an ideal perimeter has reduced the radiation resistance. The adequate number of iterations needed to design the antenna is calculated based on λ. (author) [es

Compact antennas for wireless communications and terminals theory and design

CERN Document Server

Laheurte, Jean-Marc

2012-01-01

Compact Antennas for Wireless Communications and Terminals deals with compact microwave antennas and, more specifically, with the planar version of these antennas. Planar antennas are the most appropriate type of antenna in modern communication systems and more generally in all applications requiring miniaturization, integration and conformation such as in mobile phone handsets.The book is suitable for students, engineers and scientists eager to understand the principles of planar and small antennas, their design and fabrication issues, and modern aspects such as UWB antennas, recon

Dual-Beam Antenna Design for Autonomous Sensor Network Applications

Directory of Open Access Journals (Sweden)

Jean-Marie Floc'h

2012-01-01

Full Text Available This paper describes our contribution in the ANR project called CAPNET dedicated to the site security (autonomous sensor network. The network is autonomous in term of energy and it is very easy to deploy on the site (the time to deploy each node of the network is around 10 minutes. The first demonstrator was deployed in the fire base station of Brest, France with 10 nodes with a security perimeter around 1.5 km. Our contribution takes place in the field of antennas, with the development of two systems: a single-beam antenna reserved for the supervisor or the last node of the network, and a dual-beam antenna dedicated to the node in linear configuration. For the design and optimization of antennas, we use HFSS CAD software from ANSOFT. The antennas have been designed and successfully measured.

2-D Fractal Wire Antenna Design and Performance

Science.gov (United States)

Tebbens, S. F.; Barton, C. C.; Peterman, D. J.; Ewing, J. J.; Abbott, C. S.; Rizki, M. M.

2017-12-01

A 2-D fractal wire antenna uses a fractal (self-similar) pattern to increase its length by iteration and can receive or transmit electromagnetic radiation. 2-D fractals are shapes that, at their mathematical limit (of infinite iterations) have an infinite length. The fractal dimension describes the degree of space filling. A fundamental property of fractal antennas lies in iteration (repetition) of a fractal pattern over a range of length scales. Iteration produces fractal antennas that can be very compact, wideband and multiband. As the number of iterations increases, the antenna tends to have additional frequencies that minimize far field return loss. This differs from traditional antenna designs in that a single fractal antenna can operate well at multiple frequencies. We have created a MATLAB code to generate deterministic and stochastic modes of fractal wire antennas with a range of fractal dimensions between 1 and 2. Variation in fractal dimension, stochasticity, and number of iterations have been computationally tested using COMSOL Multiphysics software to determine their effect on antenna performance.

Distortion and residual stresses in structures reinforced with titanium straps for improved damage tolerance

International Nuclear Information System (INIS)

Liljedahl, C.D.M.; Fitzpatrick, M.E.; Edwards, L.

2008-01-01

Distortion and residual stresses induced during the manufacturing process of bonded crack retarders have been investigated. Titanium alloy straps were adhesively bonded to an aluminium alloy SENT specimen to promote fatigue crack growth retardation. The effect of three different strap dimensions was investigated. The spring-back of a component when released from the autoclave and the residual stresses are important factors to take into account when designing a selective reinforcement, as this may alter the local aerodynamic characteristics and reduce the crack bridging effect of the strap. The principal problem with residual stresses is that the tensile nature of the residual stresses in the primary aluminium structure has a negative impact on the crack initiation and crack propagation behaviour in the aluminium. The residual stresses were measured with neutron diffraction and the distortion of the specimens was measured with a contour measurement machine. The bonding process was simulated with a three-dimensional FE model. The residual stresses were found to be tensile close to the strap and slightly compressive on the un-bonded side. Both the distortion and the residual stresses increased with the thickness and the width of the strap. Very good agreement between the measured stresses and the measured distortion and the FE simulation was found

The effect of ICRF antenna phasing on metal impurities in TFTR

International Nuclear Information System (INIS)

Stevens, J.E.; Bush, C.; Colestock, P.L.; Oak Ridge National Lab., TN; AN Ukrainskoj SSR, Kharkov

1989-07-01

ICRF power levels of up to 2.8 MW were achieved during the 1988 experimental run on TFTR. Metal impurity concentrations (Ti, Cr, Fe, Ni) and Z eff were monitored during ICRF heating by x-ray pulse height analysis and uv spectroscopy. Antenna phasing was the key variable affecting ICRF performance. No increase in metallic impurities was observed for P rf approx lt 2.8 MW with the antenna straps 0-Π, while a measurable increase in titanium (Faraday screen material) was observed for P rf approx gt 1.0 MW with 0-0 phasing. 18 refs., 8 figs

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.

5G MIMO Conformal Microstrip Antenna Design

Directory of Open Access Journals (Sweden)

Qian Wang

2017-01-01

Full Text Available With the development of wireless communication technology, 5G will develop into a new generation of wireless mobile communication systems. MIMO (multiple-input multiple-output technology is expected to be one of the key technologies in the field of 5G wireless communications. In this paper, 4 pairs of microstrip MIMO conformal antennas of 35 GHz have been designed. Eight-element microstrip Taylor antenna array with series-feeding not only achieves the deviation of the main lobe of the pattern but also increases the bandwidth of the antenna array and reduces sidelobe. MIMO antennas have been fabricated and measured. Measurement results match the simulation results well. The return loss of the antenna at 35 GHz is better than 20 dB, the first sidelobe level is −16 dB, and the angle between the main lobe and the plane of array is 60°.

Method of making steel strapping and strip

Energy Technology Data Exchange (ETDEWEB)

Robert D. Reilly

2000-02-16

The technical progress obtained for this time frame consisted of the awarding of two contracts for determination of metallurgical parameters for heat treatment of strapping and strip which are unavailable from current technology and/or published data in this field. The two contractors were Bricmont, Inc. and the Department of Materials Science and Engineering at the Technological Institute of Northwestern University, Evanston, IL. Phase 1 of the two stage contract with Bricmont, Inc. which provided a computer analysis of the cooling rates of a typical range of thickness' of strapping was completed. This study was developed for the purpose of determining the time parameters for quenching low carbon steels to a martensitic microstructure within the time frame of the design of the proposed process. It also provides design criteria for cooling to ambient for the total process. This data is required for Phase 2 of the Bricmont proposal which completes the design and specifications of the total heat treating and cooling system for the process. This becomes the basis for developing the cost and space requirements for this component of the production line. The authors do not intend to award Phase 2 until the work done at Northwestern University discussed hereafter is completed. On or about May 1, 1999 a contract for a project entitled ``Effects of Steel Composition and Quench Rate on Microstructure and Mechanical Properties of Strapping'' to be performed at the Department of Materials Science and Engineering was awarded. The delay in initiating this project was due to the legal interpretation and final agreement of the intellectual provisions of the award by the author's attorneys, Northwestern's attorneys and the legal representative in the Chicago office of the DOE. The work to date includes rapid quenching of a number of different steel compositions and microstructure on an existing drop quench test apparatus. It was initially assumed that this

Antenna Design for Directivity-Enhanced Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Aftab Ahmed

2012-01-01

Full Text Available Antenna performance can be described by two fundamental parameters: directivity and radiation efficiency. Here, we demonstrate nanoantenna designs in terms of improved directivity. Performance of the antennas is demonstrated in Raman scattering experiments. The radiated beam is directed out of the plane by using a ground plane reflector for easy integration with commercial microscopes. Parasitic elements and parabolic and waveguide nanoantennas with a ground plane are explored. The nanoantennas were fabricated by a series of electron beam evaporation steps and focused ion beam milling. As we have shown previously, the circular waveguide nanoantenna boosts the measured Raman signal by 5.5x with respect to a dipole antenna over a ground plane; here, we present the design process that led to the development of that circular waveguide nanoantenna. This work also shows that the parabolic nanoantenna produces a further fourfold improvement in the measured Raman signal with respect to a circular waveguide nanoantenna. The present designs are nearly optimal in the sense that almost all the beam power is coupled into the numerical aperture of the microscope. These designs can find applications in microscopy, spectroscopy, light-emitting devices, photovoltaics, single-photon sources, and sensing.

2-D Fractal Carpet Antenna Design and Performance

Science.gov (United States)

Barton, C. C.; Tebbens, S. F.; Ewing, J. J.; Peterman, D. J.; Rizki, M. M.

2017-12-01

A 2-D fractal carpet antenna uses a fractal (self-similar) pattern to increase its perimeter by iteration and can receive or transmit electromagnetic radiation within its perimeter-bounded surface area. 2-D fractals are shapes that, at their mathematical limit (infinite iterations) have an infinite perimeter bounding a finite surface area. The fractal dimension describes the degree of space filling and lacunarity which quantifies the size and spatial distribution of open space bounded by a fractal shape. A key aspect of fractal antennas lies in iteration (repetition) of a fractal pattern over a range of length scales. Iteration produces fractal antennas that are very compact, wideband and multiband. As the number of iterations increases, the antenna operates at higher and higher frequencies. Manifestly different from traditional antenna designs, a fractal antenna can operate at multiple frequencies simultaneously. We have created a MATLAB code to generate deterministic and stochastic modes of Sierpinski carpet fractal antennas with a range of fractal dimensions between 1 and 2. Variation in fractal dimension, stochasticity, number of iterations, and lacunarities have been computationally tested using COMSOL Multiphysics software to determine their effect on antenna performance

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.

DTU-ESA millimeter-wave validation standard antenna – requirements and design

DEFF Research Database (Denmark)

Pivnenko, Sergey; Kim, Oleksiy S.; Breinbjerg, Olav

2014-01-01

from a validation campaign is achieved when a dedicated Validation Standard (VAST) antenna specifically designed for this purpose is available. The driving requirements to VAST antennas are their mechanical stability with respect to any orientation of the antenna in the gravity field and thermal...... are briefly reviewed and the baseline design is described. The emphasis is given to definition of the requirements for the mechanical and thermal stability of the antenna, which satisfy the stringent stability requirement for the mm-VAST electrical characteristics....

Optimal design of resonant-mass gravitational wave antennas

International Nuclear Information System (INIS)

Price, J.C.

1987-01-01

A new generation of resonant-mass gravitational wave antennas, to be operated at ultralow temperatures, is under development by several research groups. This paper presents a theory for the optimal design of the new antennas. First, a general sensitivity limit is derived, which may be applied to any linear instrument for which the design figure of merit is the signal-to-noise ratio (SNR). By replacing the amplifier by its noise resistance and considering the energy dissipated in the noise resistance when a signal is applied, it is possible to show that the optimally filtered SNR is less than or equal to E/sub r//(kT/sub n/), the energy dissipated in the noise resistance divided by Boltzmann's constant times the amplifier noise temperature. This sensitivity limit will be achieved if the instrument is lossless, in which case the energy dissipated in the noise resistance is equal to the energy deposited in the system by the signal. For resonant-mass gravitational wave antennas, if the amplifier is identified as the mechanical amplifier (transducer and electronic amplifier together), then the lossless limit is accessible in practice. A useful point of view is that optimal antenna designs are those that are most loss tolerant: those that achieve the limiting SNR with the lowest possible mechanical Q values. The techniques of network synthesis may be used to design mechanical networks for matching the main antenna mass to the mechanical amplifier that are optimal in this sense. A class of loss-tolerant networks has been synthesized; their properties are summarized in a set of design charts that give the Q requirements and bandwidth as a function of the number of modes, the temperature, and the amplifier noise resistance and noise temperature

Preparing ITER ICRF: development and analysis of the load resilient matching systems based on antenna mock-up measurements

International Nuclear Information System (INIS)

Messiaen, A.; Vervier, M.; Dumortier, P.; Grine, D.; Lamalle, P.U.; Durodie, F.; Koch, R.; Louche, F.; Weynants, R.

2009-01-01

The reference design for the ICRF antenna of ITER is constituted by a tight array of 24 straps grouped in eight triplets. The matching network must be load resilient for operation in ELMy discharges and must have antenna spectrum control for heating or current drive operation. The load resilience is based on the use of either hybrid couplers or conjugate-T circuits. However, the mutual coupling between the triplets at the low expected loading strongly counteracts the load resilience and the spectrum control. Using a mock-up of the ITER antenna array with adjustable water load matching solutions are designed. These solutions are derived from transmission line modelling based on the measured scattering matrix and are finally tested. We show that the array current spectrum can be controlled by the anti-node voltage distribution and that suitable decoupler circuits can not only neutralize the adverse mutual coupling effects but also monitor this anti-node voltage distribution. A matching solution using four 3 dB hybrids and the antenna current spectrum feedback control by the decouplers provides outstanding performance if each pair of poloidal triplets undergoes a same load variation. Finally, it is verified by modelling that this matching scenario has the same antenna spectrum and load resilience performances as the antenna array loaded by plasma as described by the TOPICA simulation. This is true for any phasing and frequency in the ITER frequency band. The conjugate-T solution is presently considered as a back-up option.

Hybrid Robust Optimization for the Design of a Smartphone Metal Frame Antenna

Directory of Open Access Journals (Sweden)

Sungwoo Lee

2018-01-01

Full Text Available Hybrid robust optimization that combines a genetical swarm optimization (GSO scheme with an orthogonal array (OA is proposed to design an antenna robust to the tolerances arising during the fabrication process of the antenna in this paper. An inverted-F antenna with a metal frame serves as an example to explain the procedure of the proposed method. GSO is adapted to determine the design variables of the antenna, which operates on the GSM850 band (824–894 MHz. The robustness of the antenna is evaluated through a noise test using the OA. The robustness of the optimized antenna is improved by approximately 61.3% relative to that of a conventional antenna. Conventional and optimized antennas are fabricated and measured to validate the experimental results.

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

Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

KAUST Repository

Klionovski, Kirill; Shamim, Atif

2017-01-01

Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

KAUST Repository

Klionovski, Kirill

2017-11-01

Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

Quasi-static Design of Electrically Small Ultra-Wideband Antennas

Science.gov (United States)

2017-02-01

Equations. The ACD uses a constant line charge distribution and image line charge distribution (both on the -axis) to generate equipotential surfaces ...Each equipotential surface represents an ACD antenna design with a different height. In the Quasi-static Antenna Design Algorithm [2, 3, 4, 5, 6...quasi- static approximation used in the algorithm. A static charge distribution is used to generate equipotential surfaces . The equipotential surfaces

EFFECTIVENESS OF NYLON DRAG STRAPS FOR BRAKING MONORAIL SLEDS.

Science.gov (United States)

Velocity versus coast distance measurements on two monorail rocket sleds were conducted on the Holloman track to obtain numerical information on the...sleds and the drag straps. The straps as described are shown to increase the effective drag area of the monorail sleds used by approximately one square

ICH/FWCD system design for KSTAR

Energy Technology Data Exchange (ETDEWEB)

Bae, Young Dug; Kwak, J. G.; Han, J. M.; Ju, M. H.; Hong, B. G.

1997-07-01

The ICH/FWCD system for KSTAR shall initially be configured to provide 6 MW power to the plasma with one antenna. The system can be upgraded to provide 12 MW of power to the plasma with the addition of a second system that is duplicate of the first. The initial KSTAR ion cyclotron system consist of one port-mounted antenna that have four current straps. Each strap, using appropriate tuning, matching, and decoupling circuitry will be driven by an independent rf power source. The goal of this ICH/FWCD system is to deliver up to 6 MW of power to the plasma under a variety of plasma conditions. In this report, the plasma loading for various plasma conditions is computed by RANT3D code; electric property of antenna, i.e. inductance, capacitance and mutual coupling are examined; and then a brief description of the overall ICH/FWCD system is given. (author). 3 refs., 4 tabs., 25 figs.

ICH/FWCD system design for KSTAR

International Nuclear Information System (INIS)

Bae, Young Dug; Kwak, J. G.; Han, J. M.; Ju, M. H.; Hong, B. G.

1997-07-01

The ICH/FWCD system for KSTAR shall initially be configured to provide 6 MW power to the plasma with one antenna. The system can be upgraded to provide 12 MW of power to the plasma with the addition of a second system that is duplicate of the first. The initial KSTAR ion cyclotron system consist of one port-mounted antenna that have four current straps. Each strap, using appropriate tuning, matching, and decoupling circuitry will be driven by an independent rf power source. The goal of this ICH/FWCD system is to deliver up to 6 MW of power to the plasma under a variety of plasma conditions. In this report, the plasma loading for various plasma conditions is computed by RANT3D code; electric property of antenna, i.e. inductance, capacitance and mutual coupling are examined; and then a brief description of the overall ICH/FWCD system is given. (author). 3 refs., 4 tabs., 25 figs

Design, simulation and analysis a microstrip antenna using PU-EFB substrate

Science.gov (United States)

Mahmud, S. N. S.; Jusoh, M. A.; Jasim, S. E.; Zamani, A. H.; Abdullah, M. H.

2018-04-01

A low cost, light weight and easy to fabricate are the most important factor for future antennas. Microstrip patch antennas offer these advantages and suitable for communication and sensor application. This paper presents a design of simple microstrip patch antenna working on operating frequency of 2.4 GHz. The designed process has been carried out using MATLAB and HFSS software by entering 2.3 for the dielectric constant of PU-EFB. The results showed that high return loss, low bandwidth and good antenna radiation efficiency of which are -21.98 dB, 0.28 dB and 97.33%, respectively.

Global design of an active integrated antenna for millimeter wave

OpenAIRE

Marzolf, Eric; Drissi, M’hamed

2001-01-01

An active integrated antenna working in the millimeter wave has been realized in a monolithic process. The concept of active integrated antenna is first introduced, then the design of the integrated circuit based on a global approach, following electromagnetic and circuit simulations, is presented. The obtained performances of the active antenna are discussed and compared to a passive one.

Design, Fabrication, and Testing of Active Skin Antenna with 3D Printing Array Framework

Directory of Open Access Journals (Sweden)

Jinzhu Zhou

2017-01-01

Full Text Available An active skin antenna with structural load-bearing and electromagnetic functions is usually installed in the structural surface of mobile vehicles such as aircrafts, warships, and high-speed train. This paper presents the design, fabrication, and testing of a novel active skin antenna which consists of an encapsulation shell, antenna skin, and RF and beam control circuits. The antenna skin which consists of the facesheet, honeycomb, array framework, and microstrip antenna elements was designed by using Bayesian optimization, in order to improve the design efficiency. An active skin antenna prototype with 32 microstrip antenna elements was fabricated by using a hybrid manufacturing method. In this method, 3D printing technology was applied to fabricate the array framework, and the different layers were bonded to form the final antenna skin by using traditional composite process. Some experimental testing was conducted, and the testing results validate the feasibility the proposed antenna skin structure. The proposed design and fabrication technique is suitable for the development of conformal load-bearing antenna or smart skin antenna installed in the structural surface of aircraft, warships, and armored vehicles.

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.

Ion Bernstein wave antenna design for DIII-D

International Nuclear Information System (INIS)

Phelps, R.D.; Mayberry, M.J.; Pinsker, R.J.

1989-01-01

An array of two toroidal loop antennas has been designd and installed on the DIII-D tokamak to carry out Ion Bernstein Wave (IBW) heating experiments. The antenna will operate at the 2 MW level and provide direct excitation of the IBW over the frequency range of 30-60 MHz. This device will permit the study of coupling th IBW to divertor plasmas and will provide a menas for improving the confinement and stability of high beta plasmas through localized off-axis heating. This paper describes both the mechanical and electromagnetic design of the IBW antenna. (author). 2 refs.; 4 figs.; 1 tab

Tourniquet pressures: strap width and tensioning system widths.

Science.gov (United States)

Wall, Piper L; Coughlin, Ohmar; Rometti, Mary; Birkholz, Sarah; Gildemaster, Yvonne; Grulke, Lisa; Sahr, Sheryl; Buising, Charisse M

2014-01-01

Pressure distribution over tourniquet width is a determinant of pressure needed for arterial occlusion. Different width tensioning systems could result in arterial occlusion pressure differences among nonelastic strap designs of equal width. Ratcheting Medical Tourniquets (RMTs; m2 inc., http://www.ratcheting buckles.com) with a 1.9 cm-wide (Tactical RMT) or 2.3 cm-wide (Mass Casualty RMT) ladder were directly compared (16 recipients, 16 thighs and 16 upper arms for each tourniquetx2). Then, RMTs were retrospectively compared with the windlass Combat Application Tourniquet (C-A-T ["CAT"], http://combattourniquet.com) with a 2.5 cm-wide internal tensioning strap. Pressure was measured with an air-filled No. 1 neonatal blood pressure cuff under each 3.8 cm-wide tourniquet. RMT circumferential pressure distribution was not uniform. Tactical RMT pressures were not higher, and there were no differences between the RMTs in the effectiveness, ease of use ("97% easy"), or discomfort. However, a difference did occur regarding tooth skipping of the pawl during ratchet advancement: it occurred in 1 of 64 Tactical RMT applications versus 27 of 64 Mass Casualty RMT applications. CAT and RMT occlusion pressures were frequently over 300 mmHg. RMT arm occlusion pressures (175-397 mmHg), however, were lower than RMT thigh occlusion pressures (197-562 mmHg). RMT effectiveness was better with 99% reached occlusion and 1% lost occlusion over 1 minute versus the CAT with 95% reached occlusion and 28% lost occlusion over 1 minute. RMT muscle tension changes (up to 232 mmHg) and pressure losses over 1 minute (24±11 mmHg arm under strap to 40±12 mmHg thigh under ladder) suggest more occlusion losses may have occurred if tourniquet duration was extended. The narrower tensioning system Tactical RMT has better performance characteristics than the Mass Casualty RMT. The 3.8 cm-wide RMTs have some pressure and effectiveness similarities and differences compared with the CAT. Clinically

The Study and Implementation of Electrically Small Printed Antennas for an Integrated Transceiver Design

Energy Technology Data Exchange (ETDEWEB)

Speer, Pete [Univ. of Kansas, Lawrence, KS (United States)

2009-04-28

This work focuses on the design and evaluation of the inverted-F, meandering-monopole, and loop antenna geometries. These printed antennas are studied with the goal of identifying which is suitable for use in a miniaturized transceiver design and which has the ability to provide superior performance using minimal Printed Circuit Board (PCB) space. As a result, the main objective is to characterize tradeoffs and identify which antenna provides the best compromise among volume, bandwidth and efficiency. For experimentation purposes, three types of meandering-monopole antenna are examined resulting in five total antennas for the study. The performance of each antenna under study is evaluated based upon return loss, operational bandwidth, and radiation pattern characteristics. For our purposes, return loss is measured using the S11-port reflection coefficient which helps to characterize how well the small antenna is able to be efficiently fed. Operational bandwidth is measured as the frequency range over which the antenna maintains 2:1 Voltage Standing Wave Ratio (VSWR) or equivalently has 10-dB return loss. Ansoft High Frequency Structure Simulator (HFSS) is used to simulate expected resonant frequency, bandwidth, VSWR, and radiation pattern characteristics. Ansoft HFSS simulation is used to provide a good starting point for antenna design before actual prototype are built using an LPKF automated router. Simulated results are compared with actual measurements to highlight any differences and help demonstrate the effects of antenna miniaturization. Radiation characteristics are measured illustrating how each antenna is affected by the influence of a non-ideal ground plane. The antenna with outstanding performance is further evaluated to determine its maximum range of communication. Each designs range performance is evaluated using a pair of transceivers to demonstrate round-trip communication. This research is intended to provide a knowledge base which will help

Antenna theory analysis and design

CERN Document Server

Balanis, Constantine A

2005-01-01

The discipline of antenna theory has experienced vast technological changes. In response, Constantine Balanis has updated his classic text, Antenna Theory, offering the most recent look at all the necessary topics. New material includes smart antennas and fractal antennas, along with the latest applications in wireless communications. Multimedia material on an accompanying CD presents PowerPoint viewgraphs of lecture notes, interactive review questions, Java animations and applets, and MATLAB features. Like the previous editions, Antenna Theory, Third Edition meets the needs of e

A Design of Dual Broadband Antenna in Mobile Communication System

Directory of Open Access Journals (Sweden)

Jianming Zhou

2015-01-01

Full Text Available A design of dual broadband antenna is proposed in this paper; it consists of one low frequency unit and two high frequency units. The low frequency unit consists of a pair of printing vibrators; the high frequency unit consists of a pair of printing oscillators, which is bent at its end, and high frequency unit and low frequency unit are set on the same dielectric substrate. Through adding a parasitic unit on antenna, it can enhance frequency bandwidth without affecting the bandwidth. In the high frequency unit, it adopts gap-coupled microstrip line feeding method in order to get enough bandwidth. Through the test of dual broadband antenna, it can be found that, in the low frequency part, the antenna covers 20% bandwidth of the total bandwidth, and it covers the frequency from 800 MHz to 980 MHz. In the high frequency, the antenna covers 60% of total bandwidth and its frequency is from 1540 MHz to 2860 MHz, so the designed antenna can satisfy the frequency requirements of 2G/3G/LTE (4G communication system.

Grid lattice with sliding strap

International Nuclear Information System (INIS)

Jabsen, F.S.

1977-01-01

The invention provides means for inserting tubular members into a grid structure without mutual contact between the tubular members. After the tubular members are inserted, a movable strap is slid into position, thereby engaging, locating, and supporting the tubular member in a fixed location. (Auth.)

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.

Structural Design of the DTU-ESA MM-Wave Validation Standard Antenna

DEFF Research Database (Denmark)

Branner, Kim; Berring, Peter; Markussen, Christen Malte

2015-01-01

A new specially designed antenna to be used for inter-comparisons and validation of antenna test facilities is under development in cooperation between DTU and TICRA under a contract from the European Space Agency. The antenna is designed to be extremely thermally and mechanically stable...... in the range of temperatures 20±5°C under arbitrary orientation in the gravity field. The antenna has a characteristic length of approximately 500mm. And in order to obtain very low measuring error, the allowable deformations of the reflector and feeds are down to 2.5μm. The antenna is modelled structurally...... is connected via a glued contact formulation in MSC.MARC. Because of the size and the complexity of the model a computer cluster is applied to solve the analyses. This paper describes the structural solution to meet these extremely strict stability requirements and the structural analyses done in order...

Hiking strap force decreases during sustained upwind sailing

DEFF Research Database (Denmark)

Buchardt, R; Bay, Jonathan; Bojsen-Møller, Jens

2017-01-01

The hypothesis, that sailing upwind in wind speeds above 12 knots causes fatigue, which manifests as a reduction in exerted hiking strap force and/or maximal isometric voluntary contraction force (MVC) of the knee extensors, was evaluated. Additionally, it was investigated if a relationship exists...... between maximal exerted hiking force (hMVC) and sailing performance. In part 1 of the study, 12 national level athletes sailed upwind for 2 × 10 min while hiking strap forces were continuously acquired. Before, in between and after sailing periods, the MVC of the knee extensors was measured. In part 2...... of the study, hMVC was measured dry land in a hiking bench and correlated with the overall results at a national championship. Hiking strap force decreased from the first to the last minute in both 10 min sailing periods (430 ± 131 vs. 285 ± 130 N, P 

Identification of a subunit of NADH-dehydrogenase as a p49/STRAP-binding protein

Directory of Open Access Journals (Sweden)

Zhong Ying

2008-01-01

Full Text Available Abstract Background The p49/STRAP (or SRFBP1 protein was recently identified in our laboratory as a cofactor of serum response factor that contributes to the regulation of SRF target genes in the heart. Results In the present study, we report that NDUFAB1, a nuclear encoded subunit of NADH dehydrogenase, represented the majority of the cDNA clones that interacted with p49/STRAP in multiple screenings using the yeast two-hybrid system. The p49/STRAP and NDUFAB1 proteins interacted and co-localized with each other in the cell. The p49/STRAP protein contains four classic nuclear localization sequence motifs, and it was observed to be present predominantly in the nucleus. Overexpression of p49/STRAP altered the intracellular level of NAD, and reduced the NAD/NADH ratio. Overexpression of p49/STRAP also induced the deacetylation of serum response factor. Conclusion These data suggest that p49/STRAP plays a role in the regulation of intracellular processes such as cardiac cellular metabolism, gene expression, and possibly aging.

Rf modeling and design of a folded waveguide launcher for the Alcator C-Mod tokamak

International Nuclear Information System (INIS)

Bigelow, T.S.; Fogelman, C.F.; Baity, F.W.; Carter, M.D.; Hoffman, D.J.; Ryan, P.M.; Yugo, J.J.; Golovato, S.N.; Bonoli, P.

1993-01-01

The folded waveguide (FWG) launcher is being investigated as an improved antenna configuration for plasma heating in the ion cyclotron range of frequencies (ICRF). A development FWG launcher was successfully tested at Oak Ridge National Laboratory (ORNL) with a low-density plasma load and found to have significantly greater power density capability than current strap-type antennas operating in similar plasmas. To further test the concept on a high density tokamak plasma, a collaboration has been set up between ORNL and Massachusetts Institute of Technology (MIT) to develop and test an 80-MHz, 2-MW FWG on the Alcator C-Mod tokamak at MIT. The radio frequency (rf) electromagnetic modeling techniques and laboratory measurements used in the design of this antenna are described in this paper. A companion paper describes the mechanical design of the FWG

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

Design of a Compact Wideband Antenna Array for Microwave Imaging Applications

Directory of Open Access Journals (Sweden)

J. Puskely

2013-12-01

Full Text Available In the paper, wideband antenna arrays aimed at microwave imaging applications and SAR applications operating at Ka band were designed. The antenna array feeding network is realized by a low-loss SIW technology. Moreover, we have replaced the large feed network comprised of various T and Y junctions by a simple broadband network of compact size to more reduce losses in the substrate integrated waveguide and also save space on the PCB. The designed power 8-way divider is complemented by a wideband substrate integrated waveguide to a grounded coplanar waveguide transition and directly connected to the antenna elements. The measured results of antenna array are consistent with our simulation. Obtained results of the developed array demonstrated improvement compared to previously developed binary feed networks with microstrip or SIW splitters.

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.

Design of 5.8 GHz Integrated Antenna on 180nm Complementary Metal Oxide Semiconductor (CMOS) Technology

Science.gov (United States)

Razak, A. H. A.; Shamsuddin, M. I. A.; Idros, M. F. M.; Halim, A. K.; Ahmad, A.; Junid, S. A. M. Al

2018-03-01

This project discusses the design and simulation performances of integrated loop antenna. Antenna is one of the main parts in any wireless radio frequency integrated circuit (RFIC). Naturally, antenna is the bulk in any RFIC design. Thus, this project aims to implement an integrated antenna on a single chip making the end product more compact. This project targets 5.8 GHz as the operating frequency of the integrated antenna for a transceiver module based on Silterra CMOS 180nm technology. The simulation of the antenna was done by using High Frequency Structure Simulator (HFSS). This software is industrial standard software that been used to simulate all electromagnetic effect including antenna simulation. This software has ability to simulate frequency at range of 100 MHz to 4 THz. The simulation set up in 3 dimension structure with driven terminal. The designed antenna has 1400um of diameter and placed on top metal layer. Loop configuration of the antenna has been chosen as the antenna design. From the configuration, it is able to make the chip more compact. The simulation shows that the antenna has single frequency band at center frequency 5.8 GHz with -48.93dB. The antenna radiation patterns shows, the antenna radiate at omnidirectional. From the simulation result, it could be concluded that the antenna have a good radiation pattern and propagation for wireless communication.

Double Ring Antenna Design for MIMO Application in Mobile Terminals

DEFF Research Database (Denmark)

Zhao, Kun; Zhang, Shuai; Ying, Zhinong

2015-01-01

In this paper, We present a MIMO bezel antenna design composed by a seamless double metal ring structure. The MIMO antenna mainly operates in the loop mode and can cover the majority of globe cellular bands. Good efficiencies (>-4dB) and a low envelope correlation coefficient (<0.5) are achieved,...

Fretting Fatigue Behaviour of Pin-Loaded Thermoset Carbon-Fibre-Reinforced Polymer (CFRP Straps

Directory of Open Access Journals (Sweden)

Fabio Baschnagel

2016-04-01

Full Text Available This paper focuses on the fretting fatigue behaviour of pin-loaded carbon-fibre-reinforced polymer (CFRP straps studied as models for rigging systems in sailing yachts, for suspenders of arch bridges and for pendent cables in cranes. Eight straps were subjected to an ultimate tensile strength test. In total, 26 straps were subjected to a fretting fatigue test, of which ten did not fail. An S–N curve was generated for a load ratio R of 0.1 and a frequency f of 10 Hz, showing a fatigue limit stress of the straps around the matrix fatigue limit, corresponding to 46% of the straps’ ultimate tensile strength (σUTS. The fatigue limit was defined as 3 million load cycles (N = 3 × 106, but tests were even conducted up to N = 11.09 × 106. Catastrophic failure of the straps was initiated in their vertex areas. Investigations on the residual strength and stiffness properties of straps tested around the fatigue limit stress (for N ≥ 1 × 106 showed little influence of the fatigue loading on these properties. Quasi-static finite element analyses (FEA were conducted. The results obtained from the FEA are in good agreement with the experiments and demonstrate a fibre parallel stress concentration in the vertex area of factor 1.3, under the realistic assumption of a coefficient of friction (cof between pin and strap of 0.5.

A Compact Design of Planar Array Antenna with Fractal Elements for Future Generation Applications

DEFF Research Database (Denmark)

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

2016-01-01

In this paper, a planar phased array fractal antenna for the future fifth generation (5G) applications is presented. The proposed array antenna is designed to operate at 22 GHz. 64 patch antenna elements with coaxial-probe feeds have been used for the proposed design. The antenna elements are based...... on Vicsek fractal geometry where the third iteration patches operate over a wide bandwidth and contribute to improve the efficiency and realized gain performance. The designed planar array has more than 22 dB realized gain and -0.3 dB total efficiency when its beam is tilted to 0 degrees elevation...

Design of optical antenna for solar energy collection

International Nuclear Information System (INIS)

Gallo, Michele; Mescia, Luciano; Losito, Onofrio; Bozzetti, Michele; Prudenzano, Francesco

2012-01-01

In this paper, an antenna array is designed in order to transform the thermal energy, provided by the Sun and re-emitted from the Earth, in electricity. The proposed antenna array is constituted by four square spirals of gold printed on a low cost dielectric substrate. A microstrip line, embedded into the substrate, is used to feed the array and to collect the thermal radiation. The dispersive behavior of gold at infrared frequencies has been taken into account through the Lorentz–Drude model. Simulations have been conducted in order to investigate the behavior of the antenna array illuminated by a circularly polarized plane wave with an amplitude chosen according to the Stefan–Boltzmann radiation law. An output current of about 3.8 μA has been simulated at 28.3 THz, i.e. at the frequency of the Earth emitted radiation. Moreover, these infrared antennas could be coupled with other components to obtain direct rectification of infrared radiation. As a consequence, these structures further optimized could be a promising alternative to the conventional photovoltaic solar cells.

Comparison of the effects of an ICRF antenna with insulating side limiters with and without a Faraday screen on the edge parameters of a tokamak plasma

International Nuclear Information System (INIS)

Sorensen, J.; Diebold, D.A.; Majeski, R.; Hershkowitz, N.

1993-01-01

The PHAEDRUS-T tokamak was operated with radiofrequency power near the ion cyclotron frequency at 90 deg. C phasing between two current straps with and without a stainless steel Faraday screen covering the antenna. In both cases, the sides of the antenna were protected by insulating limiters. The plasma parameters in the scrape-off layer were measured and were shown to be essentially the same when radiofrequency power was applied from the Faraday screen covered antenna as compared with the antenna without a Faraday screen. The intensity of Fe(XVI) light dropped an order of magnitude after the screen was removed. (author). 18 refs, 3 figs

The design and simulation of UHF RFID microstrip antenna

Science.gov (United States)

Chen, Xiangqun; Huang, Rui; Shen, Liman; Liu, Liping; Xiong, Dezhi; Xiao, Xiangqi; Liu, Mouhai; Renheng, Xu

2018-02-01

At present, China has delineated UHF RFID communicating frequency range which is 840 ∼ 845 MHz and 920 ∼ 925 MHz, but most UHF microstrip antenna don’t carry out this standard, that leads to radio frequency pollution. In order to solve the problems above, a method combining theory and simulation is adopted. Combining with a new ceramic material, a 925.5 MHz RFID microstrip antenna is designed, which is optimized and simulated by HFSS software. The results show that the VSWR of this RFID microstrip antenna is relatively small in the vicinity of 922.5 MHz, the gain is 2.1 dBi, which can be widely used in China’s UHF RFID communicating equipments.

Design Studies of Ultra-Wideband Microstrip Antennas with a Small Capacitive Feed

Directory of Open Access Journals (Sweden)

Veeresh G. Kasabegoudar

2007-01-01

Full Text Available The design of an ultra-wideband microstrip patch antenna with a small coplanar capacitive feed strip is presented. The proposed rectangular patch antenna provides an impedance bandwidth of nearly 50%, and has stable radiation patterns for almost all frequencies in the operational band. Results presented here show that such wide bandwidths are also possible for triangular and semiellipse geometries with a similar feed arrangement. The proposed feed is a very small strip placed very close to the radiator on a substrate above the ground plane. Shape of the feed strip can also be different, so long as the area is not changed. Experimental results agree with the simulated results. Effects of key design parameters such as the air gap between the substrate and the ground plane, the distance between radiator patch and feed strip, and the dimensions of the feed strip on the input characteristics of the antenna have been investigated and discussed. As demonstrated here, the proposed antenna can be redesigned for any frequency in the L-, S-, C-, or X-band. A design criterion for the air gap has been empirically obtained to enable maximum antenna bandwidth for all these operational frequencies.

Time efficient method for automated antenna design for wireless energy harvesting

NARCIS (Netherlands)

Visser, H.J.; Vullers, R.J.M.

2010-01-01

The rectifier circuit in a rectenna (rectifying antenna) is analyzed employing a fast, efficient time-marching algorithm. The thus found complex input impedance dictates the antenna design. To maximize RF-to-DC conversion efficiency we do not want to employ an impedance matching and filtering

Efficient Design of Flexible and Low Cost Paper-Based Inkjet-Printed Antenna

Directory of Open Access Journals (Sweden)

A. M. Mansour

2015-01-01

Full Text Available A new, efficient, flexible, and cheap antenna designed at 1.57 GHz microstrip patch antenna based on simple inkjet printer with improved performance using silver nanoparticles ink is developed. The antenna is printed on a kind of flexible substrate “glossy paper,” to offer the advantage of light and flexibility for different applications. The performance of silver nanoparticles ink has been studied through inkjet printing versus postsynthesis annealing and multilayer printing. The conductivity has been improved to have promising values up to 2 Ω/cm at temperatures up to 180°C. The surface morphology of the circuits has been analyzed using SEM with mean diameter of the nanoparticles around 100 nm, uniform surface distribution, and mean thickness of the printed layer around 230 microns. Also, a simple design of a coplanar waveguide (CPW monopole Z-shaped antenna has been considered as an application of fabricated printed antenna using the studied silver nanoparticles ink through a cheap printer.

Design of Meander-Line Antennas for Radio Frequency Identification Based on Multiobjective Optimization

Directory of Open Access Journals (Sweden)

X. L. Travassos

2012-01-01

Full Text Available This paper presents optimization problem formulations to design meander-line antennas for passive UHF radio frequency identification tags based on given specifications of input impedance, frequency range, and geometric constraints. In this application, there is a need for directive transponders to select properly the target tag, which in turn must be ideally isotropic. The design of an effective meander-line antenna for RFID purposes requires balancing geometrical characteristics with the microchip impedance. Therefore, there is an issue of optimization in determining the antenna parameters for best performance. The antenna is analyzed by a method of moments. Some results using a deterministic optimization algorithm are shown.

Study of mutual coupling effects in the antenna array of the ICRH plug-in for ITER

International Nuclear Information System (INIS)

Lamalle, P.U.; Messiaen, A.; Dumortier, P.; Durodie, F.; Evrard, M.; Louche, F.

2005-01-01

The performance of the ELM-tolerant 'conjugate T' (CT) matching schemes considered for the ITER ICRH antenna array has been found highly sensitive to the mutual resistances and reactances between antenna straps, which can produce large exchanges of active power between circuit branches. A general analysis is given of the effect of mutual coupling on the matching of a single CT and on the simultaneous matching of several coupled CT circuits. Circuit configurations optimizing the resilience of the system to realistic ELM-induced load variations are given in the case of a single CT. Problems arising from the interaction between several CTs and possible remedies are discussed

Design of a broadband hexagonal-shaped zeroth-order resonance antenna with metamaterials

Energy Technology Data Exchange (ETDEWEB)

Woo, Dong Sik; Kim, Kang Wook; Choi, Hyun Chul [Kyungpook National University, Daegu (Korea, Republic of)

2014-11-15

A broadband hexagonal-shaped metamaterials (MTMs)-based zeroth-order resonant (ZOR) antenna was designed and fabricated. The hexagonal shape of a top patch on a mushroom structure makes not only direct-current paths between the two ends of the patch but also round-current paths along the outside of the patch, thereby widening the resonance frequency of the mushroom MTM antenna. According to the shape of the hexagon patch, the presented antenna achieved impedance bandwidth of 58.6% corresponding to ultra-wideband technology. The proposed ZOR antenna was modeled by utilizing a composite right- and left-handed (CRLH) transmission line and provided 4 to 9.3 dBi of the antenna gain with reduced size as compared to conventional microstrip antennas at Ku- to K-band frequencies.

TCM Analysis of Defected Ground Structures for MIMO Antenna Designs in Mobile Terminals

KAUST Repository

Ghalib, Asim

2017-08-14

In this paper, the theory of characteristic modes (TCM) is used for the first time to analyze the behavior of defected ground structures (DGS) when added to antenna designs. A properly designed DGS introduces currents opposite in direction to the original characteristic modes (CM) currents thus reducing mutual coupling. TCM is also applied to multiple-inputmultiple- output (MIMO) antenna systems to develop a systematic approach that can predict whether the isolation can be enhanced further or not. For this purpose two 4-element and one 2-element MIMO designs, i.e. monopole and planar inverted-F antennas (PIFA) are studied. The addition of different antenna elements affects the CM significantly as well as differently. Some of the CM excited on the antenna surface contribute to the coupling between the antenna ports that is why they can be classified as coupling modes. To improve the isolation, the DGS should be introduced at certain locations that blocks the coupling modes but at the same time does not affect the non-coupling modes. If their is no such location or the current on the surface of the chassis for coupling and non-coupling modes is approximately same, the isolation cannot be enhanced further. Using this approach, isolation was improved on an average by 11 dB in all the designs considered, giving the most isolation enhancement following a systematic way compared to other works.

Concept Design of a Multi-Band Shared Aperture Reflectarray/Reflector Antenna

Science.gov (United States)

Spence, Thomas; Cooley, Michael; Stenger, Peter; Park, Richard; Li, Lihua; Racette, Paul; Heymsfield, Gerald; Mclinden, Matthew

2016-01-01

A scalable dual-band (KaW) shared-aperture antenna system design has been developed as a proposed solution to meet the needs of the planned NASA Earth Science Aerosol, Clouds, and Ecosystem (ACE) mission. The design is comprised of a compact Cassegrain reflector/reflectarray with a fixed pointing W-band feed and a cross track scanned Ka-band Active Electronically Scanned Array (AESA). Critical Sub-scale prototype testing and flight tests have validated some of the key aspects of this innovative antenna design, including the low loss reflector/reflectarray surface.More recently the science community has expressed interest in a mission that offers the ability to measure precipitation in addition to clouds and aerosols. In this paper we present summaries of multiple designs that explore options for realizing a tri-frequency (KuKaW), shared-aperture antenna system to meet these science objectives. Design considerations include meeting performance requirements while emphasizing payload size, weight, prime power, and cost. The extensive trades and lessons learned from our previous dual-band ACE system development were utilized as the foundation for this work.

Long range ultra-high frequency (UHF) radio frequency identification (RFID) antenna design

Science.gov (United States)

Reynolds, Nathan D.

There is an ever-increasing demand for radio frequency identification (RFID) tags that are passive, long range, and mountable on multiple surfaces. Currently, RFID technology is utilized in numerous applications such as supply chain management, access control, and public transportation. With the combination of sensory systems in recent years, the applications of RFID technology have been extended beyond tracking and identifying. This extension includes applications such as environmental monitoring and healthcare applications. The available sensory systems usually operate in the medium or high frequency bands and have a low read range. However, the range limitations of these systems are being overcome by the development of RFID sensors focused on utilizing tags in the ultra-high frequency (UHF) band. Generally, RFID tags have to be mounted to the object that is being identified. Often the objects requiring identification are metallic. The inherent properties of metallic objects have substantial effects on nearby electromagnetic radiation; therefore, the operation of the tag antenna is affected when mounted on a metallic surface. This outlines one of the most challenging problems for RFID systems today: the optimization of tag antenna performance in a complex environment. In this research, a novel UHF RFID tag antenna, which has a low profile, long range, and is mountable on metallic surfaces, is designed analytically and simulated using a 3-D electromagnetic simulator, ANSYS HFSS. A microstrip patch antenna is selected as the antenna structure, as patch antennas are low profile and suitable for mounting on metallic surfaces. Matching and theoretical models of the microstrip patch antenna are investigated. Once matching and theory of a microstrip patch antenna is thoroughly understood, a unique design technique using electromagnetic band gap (EBG) structures is explored. This research shows that the utilization of an EBG structure in the patch antenna design yields

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.

Design and investigation of planar technology based ultra-wideband antenna with directional radiation patterns

Energy Technology Data Exchange (ETDEWEB)

Meena, M. L., E-mail: madan.meena.ece@gamil.com; Parmar, Girish, E-mail: girish-parmar2002@yahoo.com; Kumar, Mithilesh, E-mail: mith-kr@yahoo.com [Department of Electronics Engineering, Rajasthan Technical University, Kota (India)

2016-03-09

A novel design technique based on planar technology for ultra-wideband (UWB) antennas with different ground shape having directional radiation pattern is being presented here. Firstly, the L-shape corner reflector ground plane antenna is designed with microstrip feed line in order to achieve large bandwidth and directivity. Thereafter, for the further improvement in the directivity as well as for better impedance matching the parabolic-shape ground plane has been introduced. The coaxial feed line is given for the proposed directional antenna in order to achieve better impedance matching with 50 ohm transmission line. The simulation analysis of the antenna is done on CST Microwave Studio software using FR-4 substrate having thickness of 1.6 mm and dielectric constant of 4.4. The simulated result shows a good return loss (S11) with respect to -10 dB. The radiation pattern characteristic, angular width, directivity and bandwidth performance of the antenna have also been compared at different resonant frequencies. The designed antennas exhibit low cost, low reflection coefficient and better directivity in the UWB frequency band.

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.

Co-design of on-chip antennas and circuits for a UNII band monolithic transceiver

KAUST Repository

Shamim, Atif; Arsalan, Muhammad; Roy, L; Salama, Khaled N.

2012-01-01

with two on-chip antennas. Both antennas are characterized for their radiation properties through an on-wafer custom measurement setup. The strategy to co-design on-chip antennas with circuits, resultant trade-offs and measurement challenges have also been

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.

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.

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.

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.

Antenna toolkit

CERN Document Server

Carr, Joseph

2006-01-01

Joe Carr has provided radio amateurs and short-wave listeners with the definitive design guide for sending and receiving radio signals with Antenna Toolkit 2nd edition.Together with the powerful suite of CD software, the reader will have a complete solution for constructing or using an antenna - bar the actual hardware! The software provides a simple Windows-based aid to carrying out the design calculations at the heart of successful antenna design. All the user needs to do is select the antenna type and set the frequency - a much more fun and less error prone method than using a con

Co-design of on-chip antennas and circuits for a UNII band monolithic transceiver

KAUST Repository

Shamim, Atif

2012-07-28

The surge of highly integrated and multifunction wireless devices has necessitated the designers to think outside the box for solutions that are unconventional. The new trends have provided the impetus for low cost and compact RF System-on-Chip (SoC) approaches [1]. The major advantages of SoC are miniaturization and cost reduction. A major bottleneck to the true realization of monolithic RF SoC transceivers is the implementation of on-chip antennas with circuitry. Though complete integrated transceivers with on-chip antennas have been demonstrated, these designs are generally for high frequencies. Moreover, they either use non-standard CMOS processes or additional fabrication steps to enhance the antenna efficiency, which in turn adds to the cost of the system [2-3]. Another challenge related to the on-chip antennas is the characterization of their radiation properties. Most of the recently reported work (summarized in Table I) shows that very few on-chip antennas are characterized. Our previous work [4], demonstrated a Phase Lock Loop (PLL) based transmitter (TX) with an on-chip antenna. However, the radiation from the on-chip antenna experienced strong interference due to 1) some active circuitry on one side of the chip and 2) the PCB used to mount the chip in the anechoic chamber. This paper presents, for the first time, a complete 5.2 GHz (UNII band) transceiver with separate TX and receiver (RX) antennas. To the author\\'s best knowledge, its size of 3 mm2 is the smallest reported for a UNII band transceiver with two on-chip antennas. Both antennas are characterized for their radiation properties through an on-wafer custom measurement setup. The strategy to co-design on-chip antennas with circuits, resultant trade-offs and measurement challenges have also been discussed. © 2010 IEEE.

Design of an electrically small circularly polarised turnstile antenna and its application to near-field wireless power transfer

DEFF Research Database (Denmark)

Yoon, Ick-Jae; Ling, Hao

2014-01-01

An electrically small circularly polarised antenna is designed and applied to near-field wireless power transfer as a means of alleviating orientation dependence. The antenna is miniaturised from a spl lambda//2-turnstile antenna by utilising the top loading and multiple folding techniques. A loc...... performance is verified in the far field. The power transfer efficiency is then examined in the near field via simulation and measurement. It is shown that the designed circularly polarised antenna is effective in mitigating orientation dependence down to a distance of 0.2λ.......An electrically small circularly polarised antenna is designed and applied to near-field wireless power transfer as a means of alleviating orientation dependence. The antenna is miniaturised from a spl lambda//2-turnstile antenna by utilising the top loading and multiple folding techniques. A local...... numerical search is used to determine the optimal antenna dimensions to achieve good axial ratio and impedance matching. The resulting design has a kr of 0.67 and shows good circular polarisation characteristic with a 3% axial ratio bandwidth. The designed antenna is fabricated and its circular polarisation...

Design and simulation of a novel circularly polarized antenna with polarization reconfigurable characteristics

Directory of Open Access Journals (Sweden)

Zhang Hai

2016-01-01

Full Text Available A novel circularly polarized antenna with polarization reconfigurable characteristics was designed using co-simulation of Ansoft HFSS and Designer software. It consists of a dual-polarized antenna and phase switching network which act as the feed network for the dual-polarized antenna. The phase switching network was designed based on a Wilkinson power divider, where the output port was connected with SPDT to form a switching network. By controlling the SPDT state-off / on, the phase difference of the two ports could be alternated, which generated the orthogonal modes between the two ports of dual-polarized antenna. So that Left-hand circular polarization (LHCP and Right-hand circular polarization (RHCP could be achieved. The simulation shown that reflection coefficient was less than -12 dB and the axial ratio was below 3 dB between 1.8 GHz and 2.4 GHz with polarization reconfigurable characteristics.

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.

Engineering design and fabrication of ICH antenna on KSTAR

Energy Technology Data Exchange (ETDEWEB)

Bae, Y.D.; Hong, B.G.; Hwang, C.K. [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-08-01

Engineering design of 6MW ICH(Ion Cyclotron Heating) system for the plasma heating and current drive in KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak is carried out and a proto-type antenna is domestically fabricated. The proto-type antenna is installed on RF test chamber, and its mutual coupling and vacuum impedance will be measured. Furthermore, high voltage and current behavior under no-plasma load conditions will be studied using 100 kW of 30 MHz RF power. A vacuum feedthrough is designed and fabricated using two ceramic cylinder, which has power rating of 1.5 MW and pulse length of 300 sec. Its RF characteristics will be tested using 100 kW RF transmitter. 19 refs., 46 figs., 8 tabs. (Author)

Design and development of a lower-hybrid antenna for the MST reversed field pinch

International Nuclear Information System (INIS)

Thomas, M.; Cekic, M.; Lovell, T.W.; Prager, S.C.; Sarff, J.S.; Uchimoto, E.

1995-01-01

Recent theoretical studies strongly motivated the development of a radio-frequency current drive scheme for current density gradient reduction in the outer region of a reversed field pinch. The preliminary experiments using inductive current drive indicate that such current density profile modification reduces the magnetic fluctuation amplitude and related energy and particle losses. To test the theoretical predictions and to further improve confinement in the MST, the authors are planning a series of lower-hybrid wave experiments. The initial phase is the design and optimization of a low-power antenna to study slow wave propagation in a frequency range 2--3 f LH (200--300 MHz) with parallel index of refraction n parallel ∼10. Ray-tracing calculations, for typical MST plasma parameters, indicate that such a wave will spiral radially into a target zone inside the reversal layer. The antenna consists of an array of tunable loops arranged in the poloidal direction. The design is compatible with the existing box-port openings in the MST conductive shell to prevent additional magnetic field errors associated with large portholes. Antenna vacuum characteristics are studied on a test-stand designed to approximate the geometry of the MST shell. For the initial measurements of plasma response and antenna loading, the authors designed a reduced, easily insertable, vacuum antenna structure. The results of plasma impedance measurements will be compared with the numerical modeling results and incorporated in the optimized design of the antenna for wave propagation experiments

Biologically inspired coupled antenna beampattern design

Energy Technology Data Exchange (ETDEWEB)

Akcakaya, Murat; Nehorai, Arye, E-mail: makcak2@ese.wustl.ed, E-mail: nehorai@ese.wustl.ed [Department of Electrical and Systems Engineering, Washington University in St Louis, St Louis, MO 63130 (United States)

2010-12-15

We propose to design a small-size transmission-coupled antenna array, and corresponding radiation pattern, having high performance inspired by the female Ormia ochracea's coupled ears. For reproduction purposes, the female Ormia is able to locate male crickets' call accurately despite the small distance between its ears compared with the incoming wavelength. This phenomenon has been explained by the mechanical coupling between the Ormia's ears, which has been modeled by a pair of differential equations. In this paper, we first solve these differential equations governing the Ormia ochracea's ear response, and convert the response to the pre-specified radio frequencies. We then apply the converted response of the biological coupling in the array factor of a uniform linear array composed of finite-length dipole antennas, and also include the undesired electromagnetic coupling due to the proximity of the elements. Moreover, we propose an algorithm to optimally choose the biologically inspired coupling for maximum array performance. In our numerical examples, we compute the radiation intensity of the designed system for binomial and uniform ordinary end-fire arrays, and demonstrate the improvement in the half-power beamwidth, sidelobe suppression and directivity of the radiation pattern due to the biologically inspired coupling.

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.

Manufacturing error sensitivity analysis and optimal design method of cable-network antenna structures

Science.gov (United States)

Zong, Yali; Hu, Naigang; Duan, Baoyan; Yang, Guigeng; Cao, Hongjun; Xu, Wanye

2016-03-01

Inevitable manufacturing errors and inconsistency between assumed and actual boundary conditions can affect the shape precision and cable tensions of a cable-network antenna, and even result in failure of the structure in service. In this paper, an analytical sensitivity analysis method of the shape precision and cable tensions with respect to the parameters carrying uncertainty was studied. Based on the sensitivity analysis, an optimal design procedure was proposed to alleviate the effects of the parameters that carry uncertainty. The validity of the calculated sensitivities is examined by those computed by a finite difference method. Comparison with a traditional design method shows that the presented design procedure can remarkably reduce the influence of the uncertainties on the antenna performance. Moreover, the results suggest that especially slender front net cables, thick tension ties, relatively slender boundary cables and high tension level can improve the ability of cable-network antenna structures to resist the effects of the uncertainties on the antenna performance.

Porous textile antenna designs for improved wearability

Science.gov (United States)

Shahariar, Hasan; Soewardiman, Henry; Muchler, Clifford A.; Adams, Jacob J.; Jur, Jesse S.

2018-04-01

Textile antennas are an integral part of the next generation personalized wearable electronics system. However, the durability of textile antennas are rarely discussed in the literature. Typical textile antennas are prone to damage during normal wearable user scenarios, washing, and heat cycling over time. Fabricating a durable, washable, flexible, and breathable (like textile materials) antenna is challenging due to the incompatibility of the mechanical properties of conductive materials and soft textile materials. This paper describes a scalable screen printing process on an engineered nonwoven substrate to fabricate microstrip patch antennas with enhanced durability. This work used an Evolon® nonwoven substrate with low surface roughness (˜Ra = 18 μm) and high surface area (˜2.05 mm2 mm-2 of fabric area) compared to traditional textile materials, which allows the ink to penetrate evenly in the fiber bulk with its strong capillary wicking force and enhances print resolution. The composite layer of ink and fiber is conductive and enables the antennas to maintain high mechanical flexibility without varying its RF (Radio Frequency) properties. Additionally, the antennas are packaged by laminating porous polyurethane web to make the device durable and washable. The fully packaged antennas maintain the structural flexibility and RF functionality after 15 cycles of washing and drying. To improve the air permeability and enhance flexibility the antenna is also modified by incorporating holes in the both patch and ground layer of the antenna. The antennas were analyzed before and after submerging in water to observe the effect of wetting and drying with respect to frequency response. The porous antenna with holes recovered 3x times faster than the one without holes (solid) from fully wet state (saturated with water) to the dry state, demonstrating its potential use as a moisture sensor system.

Miniaturization design and implementation of magnetic field coupled RFID antenna

Science.gov (United States)

Hu, Tiling

2013-03-01

The development of internet of things has brought new opportunities and challenges to the application of RFID tags. Moreover, the Miniaturization application trend of tags at present has become the mainstream of development. In this paper, the double-layer design is to reduce the size of HF antenna, and the magnetic null point of magnetic reconnection region between the RLC resonant circuit and the reader provides sufficient energy to the miniaturization of antenna. The calculated and experimental results show that the miniaturization of HF antennas can meet the reading and writing requirement of the international standard ISO/IEC14443 standard. The results of this paper may make a positive contribution to the applications of RFID technology.

Design of optimized impedance transformer for ICRF antenna in LHD

Energy Technology Data Exchange (ETDEWEB)

Saito, K., E-mail: saito@nifs.ac.jp [National Institute for Fusion Science, Toki, Gifu, 509-5292 (Japan); Seki, T.; Kasahara, H.; Seki, R.; Kumazawa, R.; Nomura, G.; Shimpo, F.; Mutoh, T. [National Institute for Fusion Science, Toki, Gifu, 509-5292 (Japan)

2013-10-15

Highlights: ► We developed optimization method of impedance transformer for ICRF antenna. ► Power loss will be one-third with the optimized impedance transformer. ► Possibility of damage on the transmission line will be drastically reduced. ► High performance will be kept in the wide antenna impedance region. -- Abstract: A pair of ion cyclotron range of frequencies (ICRF) antennas in the large helical device (LHD), HAS antennas showed high efficiency in minority ion heating. However the low loading resistance must be increased to prevent breakdown in transmission line. Moreover, the voltage and the current around the feed-through must be reduced to protect it. For these purpose, we developed a design procedure of the impedance transformer for HAS antennas. To optimize the transformer, the inner conductors were divided into several segments and the radii of them were given discretely and independently. The maximum effective loading resistance was obtained by using all combinations of radii within the limitations of the voltage and current at the feed-through and the electric field on the transformer. To get a precise solution, this procedure was repeated several times by narrowing the range of radii of inner conductors. Then the optimized impedance transformer was designed by smoothing the radii of inner conductors. For the typical discharge, the voltage and current at the feed-through were reduced to the half of the original values with the same power. The effective loading resistance was increased to more than four times. High performance is expected in wide impedance region.

Numerical Design of Ultra-Wideband Printed Antenna for Surface Penetrating Radar Application

Directory of Open Access Journals (Sweden)

Achmad Munir

2011-08-01

Full Text Available Surface penetrating radar (SPR is an imaging device of electromagnetic wave that works by emitting and transmitting a narrow period pulse through the antenna. Due to the use of narrow period pulse, according to the Fourier transform duality, therefore ultra-wideband (UWB antenna becomes one of the most important needs in SPR system. In this paper, a novel UWB printed antenna is proposed to be used for SPR application. Basically, the proposed antenna is developed from a rectangular microstrip antenna fed by symmetric T-shaped. Some investigation methods such as resistive loading, abrupt transition, and ground plane modification are attempted to achieve required characteristics of bandwidth, radiation efficiency, and compactness needed by the system. To obtain the optimum design, the characteristics of proposed antenna are numerically investigated through the physical parameters of antenna. It is shown that proposed antenna deployed on an FR-4 Epoxy substrate with permittivity of 4.3 and thickness of 1.6mm has a compact size of 72.8mm x 60.0mm and a large bandwidth of 50MHz-5GHz which is suitable for SPR application.

A Novel Low RCS Design Method for X-Band Vivaldi Antenna

Directory of Open Access Journals (Sweden)

XiaoXiang He

2012-01-01

Full Text Available A novel low radar cross-section (RCS design method is proposed, and its application on Vivaldi antenna that covers the entire X band is investigated. According to the difference of the current distribution on the radiator when the antenna radiates or scatters, the shape of the metal radiator is modified, so that maximally 19.2 dBsm RCS reduction is achieved which satisfied radiation performance. Simulated and measured results about gain, S11, and RCS are presented. As a result, the effectiveness of the presented low RCS design method is validated.

ANTWKB: a code for the simulation of ion cyclotron antennas in tokamaks

International Nuclear Information System (INIS)

Brambilla, M.

1995-04-01

We have developed a code which evaluates the complex input impedance, the loading, and the spectral distribution of the launched power, of metallic antennas for ion cyclotron heating of large tokamak plasmas. The current distribution along the conductors is obtained selfconsistently from a variational method. The plasma response is evaluated assuming that the WKB approximation can be used already at the plasma edge, thereby avoiding the lengthy integration of the wave equations in the plasma. This makes possible systematic scans over frequency or other parameters, while retaining a sufficiently large number of Fourier components in the radiated fields to ensure convergence of both the resistive and reactive part of the power. Optionally, the code can evaluate the antenna response in vacuum or with a dummy load, for comparison with test bank measurements. We have applied the code to a few antennas of practical interest. The code reproduces accurately the expected transmission-line-like behaviour of a simple feeder-to-short antenna, and reasonably well the measured properties of the folded antenna of the ASDEX Upgrade ICRF experiment. This antenna is found to have particularly favourable properties, since its outer conductors present to the plasma a relatively uniform current over a broad range of frequencies, which, moreover, is always larger than in the return conductors. The loading of the ''violin antenna'' recently proposed for use in ITER is found to be satisfactory in the vicinity of antenna resonance, although rather poor at other frequencies. In the case of simple strap antennas replacing the short by an adjustable capacity, as in TORE SUPRA, is confirmed to be a good way of optimizing the loading. (orig.)

Design of a dual linear polarization antenna using split ring resonators at X-band

Science.gov (United States)

Ahmed, Sadiq; Chandra, Madhukar

2017-11-01

Dual linear polarization microstrip antenna configurations are very suitable for high-performance satellites, wireless communication and radar applications. This paper presents a new method to improve the co-cross polarization discrimination (XPD) for dual linear polarized microstrip antennas at 10 GHz. For this, three various configurations of a dual linear polarization antenna utilizing metamaterial unit cells are shown. In the first layout, the microstrip patch antenna is loaded with two pairs of spiral ring resonators, in the second model, a split ring resonator is placed between two microstrip feed lines, and in the third design, a complementary split ring resonators are etched in the ground plane. This work has two primary goals: the first is related to the addition of metamaterial unit cells to the antenna structure which permits compensation for an asymmetric current distribution flow on the microstrip antenna and thus yields a symmetrical current distribution on it. This compensation leads to an important enhancement in the XPD in comparison to a conventional dual linear polarized microstrip patch antenna. The simulation reveals an improvement of 7.9, 8.8, and 4 dB in the E and H planes for the three designs, respectively, in the XPD as compared to the conventional dual linear polarized patch antenna. The second objective of this paper is to present the characteristics and performances of the designs of the spiral ring resonator (S-RR), split ring resonator (SRR), and complementary split ring resonator (CSRR) metamaterial unit cells. The simulations are evaluated using the commercial full-wave simulator, Ansoft High-Frequency Structure Simulator (HFSS).

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.

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.

Design and optimization of LTE 1800 MIMO antenna.

Science.gov (United States)

Wong, Huey Shin; Islam, Mohammad Tariqul; Kibria, Salehin

2014-01-01

A multiple input and multiple output (MIMO) antenna that comprises a printed microstrip antenna and a printed double-L sleeve monopole antenna for LTE 1800 wireless application is presented. The printed double-L sleeve monopole antenna is fed by a 50 ohm coplanar waveguide (CPW). A novel T-shaped microstrip feedline printed on the other side of the PCB is used to excite the waveguide's outer shell. Isolation characteristics better than -15 dB can be obtained for the proposed MIMO antenna. The proposed antenna can operate in LTE 1800 (1710 MHz-1880 MHz). This antenna exhibits omnidirectional characteristics. The efficiency of the antenna is greater than 70% and has high gain of 2.18 dBi.

Design and Measurement of a 2.45 Ghz On-Body Antenna Optimized for Hearing Instrument Applications

DEFF Research Database (Denmark)

Kvist, Søren Helstrup; Jakobsen, Kaj Bjarne; Thaysen, Jesper

2012-01-01

A balanced PIFA-inspired antenna design is presented for use with the 2:45 GHz ear-to-ear radio channel. The antenna is designed such that the radiated electric fields are primarily polarized normal to the surface of the head, in order to obtain a high on-body path gain (jS21 j). The antenna...... structure can be made conformal to the outer surface of a hearing instrument, such that the bandwidth of the antenna is optimized given the available volume. The radiation patterns, ear-to-ear path gain and available bandwidth is measured and compared to the simulated results. It is found that the antenna...

Workshop on High Power ICH Antenna Designs for High Density Tokamaks

Science.gov (United States)

Aamodt, R. E.

1990-02-01

A workshop in high power ICH antenna designs for high density tokamaks was held to: (1) review the data base relevant to the high power heating of high density tokamaks; (2) identify the important issues which need to be addressed in order to ensure the success of the ICRF programs on CIT and Alcator C-MOD; and (3) recommend approaches for resolving the issues in a timely realistic manner. Some specific performance goals for the antenna system define a successful design effort. Simply stated these goals are: couple the specified power per antenna into the desired ion species; produce no more than an acceptable level of RF auxiliary power induced impurities; and have a mechanical structure which safely survives the thermal, mechanical and radiation stresses in the relevant environment. These goals are intimately coupled and difficult tradeoffs between scientific and engineering constraints have to be made.

Design of microstrip patch antennas using knowledge insertion through retraining

Science.gov (United States)

Divakar, T. V. S.; Sudhakar, A.

2018-04-01

The traditional way of analyzing/designing neural network is to collect experimental data and train neural network. Then, the trained neural network acts as global approximate function. The network is then used to calculate parameters for unknown configurations. The main drawback of this method is one does not have enough experimental data, cost of prototypes being a major factor [1-4]. Therefore, in this method the author collected training data from available approximate formulas with in full design range and trained the network with it. After successful training, the network is retrained with available measured results. This simple way inserts experimental knowledge into the network [5]. This method is tested for rectangular microstrip antenna and circular microstrip antenna.

Design and Simulation of Horn Antenna Using CST Software for GPR System

Science.gov (United States)

Joret, Ariffuddin; Sulong, M. S.; Abdullah, M. F. L.; Madun, Aziman; Haimi Dahlan, Samsul

2018-04-01

Detection of underground object can be made using a GPR system. This system is classified as a non-destructive technique (NDT) where the ground areas need not to be excavated. The technique used by the GPR system is by measuring the reflection of electromagnetic wave signal produced and detected by antenna which is known as the transmitter and the receiver antenna. In this study, a GPR system was studied by means of simulation using a Horn antenna as a transceiver antenna. The electromagnetic wave signal in this simulation is produced by current signal of an antenna which having a shape of modulation of Gaussian pulse which is having spectrum from 8 GHz until 12 GHz. CST and MATLAB Software are used in this GPR system simulation. A model of a Horn antenna has been designed using the CST software before the GPR’s system simulation modeled by adding a model of background in front of the Horn antenna. The simulation results show that the output signal of the Horn antenna can be used in detecting embedded object which are made from material of wood and iron. In addition, the simulation result has successfully developed a 3D model image of the GPR system using output signal of the Horn antenna. The embedded iron object in the GPR system simulation can be seen clearly by using this 3D image.

Antennas from theory to practice

CERN Document Server

Huang, Yi

2008-01-01

Practical, concise and complete reference for the basics of modern antenna design Antennas: from Theory to Practice discusses the basics of modern antenna design and theory. Developed specifically for engineers and designers who work with radio communications, radar and RF engineering, this book offers practical and hands-on treatment of antenna theory and techniques, and provides its readers the skills to analyse, design and measure various antennas. Key features: Provides thorough coverage on the basics of transmission lines, radio waves and propag

Plasmonic optical antenna design for performing tip-enhanced Raman spectroscopy and microscopy

International Nuclear Information System (INIS)

Kharintsev, S S; Fishman, A I; Salakhov, M Kh; Hoffmann, G G

2013-01-01

This paper highlights optical plasmonic antennas designed with dc-pulsed low-voltage electrochemical etching of a gold wire for implementing tip-enhanced Raman scattering (TERS) measurements. We demonstrate a versatile electrochemical system that allows one to engineer TERS-active metallic gold tips with diverse shapes and sizes in a highly reproducible fashion. The underlying etching mechanism at a voltage-driven meniscus around a gold wire immersed into an electrolyte is discussed in detail. We show that the developed method is suitable to produce not only the simplest geometries such as cones and spheroids, but more complex designs. Attempts have been made to design plasmonic tapered antennas with quasi-uniformly spaced nano-sized bumps on the mesoscopic zone for the extra surface plasmon-light coupling. The capability of the patterned antenna to enhance and localize optical fields is demonstrated with near-field Raman microscopy and spectroscopy of single-walled carbon nanotubes bundles. (paper)

Design of a Small Modified Minkowski Fractal Antenna for Passive Deep Brain Stimulation Implants

Directory of Open Access Journals (Sweden)

Sara Manafi

2014-01-01

Full Text Available A small planar modified Minkowski fractal antenna is designed and simulated in dual frequency bands (2.4 and 5.8 GHz for wireless energy harvesting by deep brain stimulation (DBS devices. The designed antenna, physically being confined inside a miniaturized structure, can efficiently convert the wireless signals in dual ISM frequency bands to the energy source to recharge the DBS battery or power the pulse generator directly. The performance metrics such as the return loss, the specific absorption rate (SAR, and the radiation pattern within skin and muscle-fat-skin tissues are evaluated for the designed antenna. The gain of the proposed antenna is 3.2 dBi at 2.4 GHz and 4.7 dBi at 5.8 GHz; also the averaged SAR of the antenna in human body tissue is found to be well below the legally allowed limit at both frequency bands. The link budget shows the received power at the distance of 25 cm at 2.4 GHz and 5.8 GHz are around 0.4 mW and 0.04 mW, which can empower the DBS implant. The large operational bandwidth, the physical compactness, and the efficiency in wireless signal reception make this antenna suitable in being used in implanted biomedical devices such as DBS pulse generators.

Real-Time Strap Pressure Sensor System for Powered Exoskeletons

Directory of Open Access Journals (Sweden)

Jesús Tamez-Duque

2015-02-01

Full Text Available Assistive and rehabilitative powered exoskeletons for spinal cord injury (SCI and stroke subjects have recently reached the clinic. Proper tension and joint alignment are critical to ensuring safety. Challenges still exist in adjustment and fitting, with most current systems depending on personnel experience for appropriate individual fastening. Paraplegia and tetraplegia patients using these devices have impaired sensation and cannot signal if straps are uncomfortable or painful. Excessive pressure and blood-flow restriction can lead to skin ulcers, necrotic tissue and infections. Tension must be just enough to prevent slipping and maintain posture. Research in pressure dynamics is extensive for wheelchairs and mattresses, but little research has been done on exoskeleton straps. We present a system to monitor pressure exerted by physical human-machine interfaces and provide data about levels of skin/body pressure in fastening straps. The system consists of sensing arrays, signal processing hardware with wireless transmission, and an interactive GUI. For validation, a lower-body powered exoskeleton carrying the full weight of users was used. Experimental trials were conducted with one SCI and one able-bodied subject. The system can help prevent skin injuries related to excessive pressure in mobility-impaired patients using powered exoskeletons, supporting functionality, independence and better overall quality of life.

Pressure Drop of Chamfer on Spacer Grid Strap

Energy Technology Data Exchange (ETDEWEB)

Kim, Euijae; Kim, Kanghoon; Kim, Kyounghong; Nahm, Keeyil [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of)

2014-05-15

A swirl flow and cross flow are generated by the spacer grid with mixing vane that enhances the thermal performance and critical heat flux (CHF). The additional pressure drop makes it difficult to meet acceptance criteria for overall pressure drop in fuel assembly depending upon the pump capacity. The chamfer on the end of spacer grid strap is one solution to reduce additional pressure drop without any adverse effect on flow fields. In this research, the pressure drop tests for spacer grid with and without chamfer were carried out at the hydraulic test facility. The result can be applied to develop high performance nuclear fuel assemblies for Pressurized Water Reactor (PWR) plants. The pressure drop tests for 5x5 spacer grid with and without chamfer as well as 6x6 spacer grid with and without chamfer were carried out at the INFINIT test facility. The Reynolds number ranged about from 16000 to 75000. The sweep-up and sweep-down test showed that the direction of sweep did not affect the pressure drop. The chamfer on spacer grid strap reduced the pressure drop due to the decreased in ratio of inlet area to outlet area. The pressure loss coefficient for spacer grid with chamfer was by up to 13.8 % lower than that for spacer grid without chamfer. Hence, the chamfer on spacer grid strap was one of effective ways to reduce the pressure drop.

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

Workshop on high power ICH antenna designs for high density tokamaks

International Nuclear Information System (INIS)

Aamodt, R.E.

1990-01-01

A workshop in high power ICH antenna designs for high density tokamaks was held in Boulder, Colorado on January 31 through February 2, 1990. The purposes of the workshop were to: (1) review the data base relevant to the high power heating of high density tokamaks; (2) identify the important issues which need to be addressed in order to ensure the success of the ICRF programs on CIT and Alcator C-MOD; and (3) recommend approaches for resolving the issues in a timely realistic manner. Some specific performance goals for the antenna system define a successful design effort. Simply stated these goals are: couple the specified power per antenna into the desired ion species; produce no more than an acceptable level of rf auxiliary power induced impurities; and have a mechanical structure which safely survives the thermal, mechanical and radiation stresses in the relevant environment. These goals are intimately coupled and difficult tradeoffs between scientific and engineering constraints have to be made

Design of books inventory with RFID antenna in library management system

Directory of Open Access Journals (Sweden)

Cheng Ching-Chien

2017-01-01

Full Text Available A 915 MHz printed radio-frequency-identification (RFID antennas with the characteristics of good gain and omnidirectional beam wave is constructed and evaluated in this study. The objective is to find out their best reading rates for providing effective wireless communications among RFID antenna during the library book inventory process. And an optimal library inventory system which is based on electromagnetic identification (EMID technology is proposed, which is constructed to find the optimal tag location for a book, test the tag readability for bookshelves, and connect a couple of multi-layer bookshelves with multiplexers and updat the tag reading status in the database of the computer terminal. The fabricated antenna reader and the proposed system are embedded into different locations of bookshelves and tested at the library of Cheng Shiu University in Taiwan. According to the experimental results, the designed prototype of the antenna reader has the characteristics of the directional radiation pattern, good gain, simple shape, low cost and is easy to be integrated into the bookshelf. And the designed library inventory system can authenticate the location of a book automatically. They can benefit administrating librarians with the capabilities of decreasing the library inventory processing time and reducing the possibility of the books being misplaced.

Design of a Circularly Polarized Galileo E6-Band Textile Antenna by Dedicated Multiobjective Constrained Pareto Optimization

Directory of Open Access Journals (Sweden)

Arnaut Dierck

2015-01-01

Full Text Available Designing textile antennas for real-life applications requires a design strategy that is able to produce antennas that are optimized over a wide bandwidth for often conflicting characteristics, such as impedance matching, axial ratio, efficiency, and gain, and, moreover, that is able to account for the variations that apply for the characteristics of the unconventional materials used in smart textile systems. In this paper, such a strategy, incorporating a multiobjective constrained Pareto optimization, is presented and applied to the design of a Galileo E6-band antenna with optimal return loss and wide-band axial ratio characteristics. Subsequently, different prototypes of the optimized antenna are fabricated and measured to validate the proposed design strategy.

Scheduling and Topology Design in Networks with Directional Antennas

Science.gov (United States)

2017-05-19

Scheduling and Topology Design in Networks with Directional Antennas Thomas Stahlbuhk, Nathaniel M. Jones, Brooke Shrader Lincoln Laboratory...controllers must choose which pairs of nodes should communicate in order to establish a topology over which traffic can be sent. Additionally...interacting effects of topology design and transmission scheduling in wireless networks, in particular focusing on networks where nodes are divided into

An Optimal Design of Multiple Antenna Positions on Mobile Devices Based on Mutual Coupling Analysis

Directory of Open Access Journals (Sweden)

Peerapong Uthansakul

2011-01-01

Full Text Available The topic of practical implementation of multiple antenna systems for mobile communications has recently gained a lot of attention. Due to the area constraint on a mobile device, the problem of how to design such a system in order to achieve the best benefit is still a huge challenge. In this paper, genetic algorithm (GA is used to find the optimal antenna positions on a mobile device. Two cases of 3×3 and 4×4 MIMO systems are undertaken. The effect of mutual coupling based on Z-parameter is the main factor to determine the MIMO capacity concerning the objective function of GA search. The results confirm the success of the proposed method to design MIMO antenna positions on a mobile device. Moreover, this paper introduces the method to design the antenna positions for the condition of nondeterministic channel. The concern of channel variation has been included in the process of finding optimal MIMO antenna positions. The results suggest that the averaging position from all GA solutions according to all channel conditions provides the most acceptable benefit.

Design and Characterization of CMOS On-Chip Antennas for 60 GHz Communications

Directory of Open Access Journals (Sweden)

D.Titz

2012-04-01

Full Text Available In this paper, we present the design and the measurement of two antennas realized on a 130nm CMOS process. They both radiate in the 60 GHz band and are dedicated to Wireless Personal Area Network (WPAN applications. The antennas are manufactured within the frame of a multi-wafer project with several surrounding microelectronic circuits. The first antenna is an Inverted-F antenna (IFA. It has a maximum gain of -8 dBi and a -10 dB matching bandwidth of 20%. The second radiator is a meandered dipole. It has a maximum gain of -14 dBi and a -10 dB matching bandwidth of 10%. The challenging measurement of their reflection coefficient and their gain radiation pattern are presented. Simulated versus measured curves are analyzed. We especially demonstrate the necessity to take into account the closest microelectronic circuits of the antennas for accurate modeling of the radiating performance of 60 GHz on-chip dies.

Design of an ion cyclotron resonance heating system for the Compact Ignition Tokamak

International Nuclear Information System (INIS)

Yugo, J.J.; Goranson, P.L.; Swain, D.W.; Baity, F.W.; Vesey, R.

1987-01-01

The Compact Ignition Tokamak (CIT) requires 10-20 MW of ion cyclotron resonance heating (ICRH) power to raise the plasma temperature to ignition. The initial ICRH system will provide 10 MW of power to the plasma, utilizing a total of six rf power units feeding six current straps in three ports. The systems may be expanded to 20 MW with additional rf power units, antennas, and ports. Plasma heating will be achieved through coupling to the fundamental ion cyclotron resonance of a 3 He minority species (also the second harmonic of tritium). The proposed antenna is a resonant double loop (RDL) structure with vacuum, shorted stubs at each end for tuning and impedance matching. The antennas are of modular, compact construction for installation and removal through the midplane port. Remote maintainability and the reactorlike operating environment have a major impact on the design of the launcher for this machine. 6 refs., 7 figs., 5 tabs

Analysis and design of efficient planar leaky-wave antennas

NARCIS (Netherlands)

Ettore, M.

2008-01-01

This thesis deals with the effective design of planar leaky-wave antennas. The work describes a methodology based on the polar expansion of Green's function representations to address very different geometrical configurations which might appear to have little in common. In fact leaky waves with

A novel e-shape communication antenna design using particle swarm optimization (PSO)

Science.gov (United States)

Mohanageetha, D.; Pavithra, R.

2013-01-01

An E-shape patch antenna is designed and demonstrated their effectiveness using Particle Swarm Optimization (PSO), which is used for wireless applications. The concept of PSO is briefly introduced in the design procedure and the design parameters are explained. This work focuses on identifying the increasing popularity of swarm intelligence specifically among the electromagnetic community. It is implemented using PSO combined with numerical algorithms for electromagnetic solutions, such as the Finite Element Method (FEM) and the Method of Moments (MOM). In both the realizations, the PSO technique drives the design variables such as antenna dimensions and geometrical features. The fitness function is evaluated for the optimizer. This is achieved by using CAD FEKO 6.1, electromagnetic simulation software. The model is designed with a resonant frequency of 2.65GHz.

SKALA, a log-periodic array antenna for the SKA-low instrument: design, simulations, tests and system considerations

Science.gov (United States)

de Lera Acedo, E.; Razavi-Ghods, N.; Troop, N.; Drought, N.; Faulkner, A. J.

2015-10-01

The very demanding requirements of the SKA-low instrument call for a challenging antenna design capable of delivering excellent performance in radiation patterns, impedance matching, polarization purity, cost, longevity, etc. This paper is devoted to the development (design and test of the first prototypes) of an active ultra-wideband antenna element for the low-frequency instrument of the SKA radio telescope. The antenna element and differential low noise amplifier described here were originally designed to cover the former SKA-low band (70-450 MHz) but it is now aimed to cover the re-defined SKA-low band (50-350 MHz) and furthermore the antenna is capable of performing up to 650 MHz with the current design. The design is focused on maximum sensitivity in a wide field of view (+/- 45° from zenith) and low cross-polarization ratios. Furthermore, the size and cost of the element has to be kept to a minimum as millions of these antennas will need to be deployed for the full SKA in very compact configurations. The primary focus of this paper is therefore to discuss various design implications for the SKA-low telescope.

Investigating Equations Used to Design a Very Small Normal-Mode Helical Antenna in Free Space

Directory of Open Access Journals (Sweden)

Dang Tien Dung

2018-01-01

Full Text Available A normal-mode helical antenna (NMHA has been applied in some small devices such as tire pressure monitoring systems (TPMS and radio frequency identification (RFID tags. Previously, electrical characteristics of NMHA were obtained through electromagnetic simulations. In practical design of NMHA, equational expressions for the main electrical characteristics are more convenient. Electrical performances of NMHA can be expressed by a combination of a short dipole and small loops. Applicability of equations for a short dipole and a small loop to very small normal-mode helical antennas such as antennas around 1/100 wavelengths was not clear. In this paper, accuracies of equations for input resistances, antenna efficiency, and axial ratios are verified by comparisons with electromagnetic simulation results by FEKO software at 402 MHz. In addition, the structure of the antenna equal to 0.021 λ is fabricated, and measurements are performed to confirm the design accuracy.

Design and Optimization of Passive UHF RFID Tag Antenna for Mounting on or inside Material Layers

Science.gov (United States)

Shao, Shuai

There is great desire to employ passive UHF RFID tags for inventory tracking and sensing in a diversity of applications and environments. Owing to its battery-free operation, non-line-of sight detection, low cost, long read range and small form factor, each year billions of RFID tags are being deployed in retail, logistics, manufacturing, biomedical inventories, among many other applications. However, the performance of these RFID systems has not met expectations. This is because a tag's performance deteriorates significantly when mounted on or inside arbitrary materials. The tag antenna is optimized only for a given type of material at a certain location of placement, and detuning takes place when attached to or embedded in materials with dielectric properties outside the design range. Thereby, different customized tags may be needed for identifying objects even within the same class of products. This increases the overall cost of the system. Furthermore, conventional copper foil-based RFID tag antennas are prone to metal fatigue and wear, and cannot survive hostile environments where antennas could be deformed by external forces and failures occur. Therefore, it is essential to understand the interaction between the antenna and the material in the vicinity of the tag, and design general purpose RFID tag antennas possessing excellent electrical performance as well as robust mechanical structure. A particularly challenging application addressed here is designing passive RFID tag antennas for automotive tires. Tires are composed of multiple layers of rubber with different dielectric properties and thicknesses. Furthermore, metallic plies are embedded in the sidewalls and steel belts lie beneath the tread to enforce mechanical integrity. To complicate matters even more, a typical tire experiences a 10% stretching during the construction process. This dissertation focuses on intuitively understanding the interaction between the antenna and the material in the

Cellular Reflectarray Antenna

Science.gov (United States)

Romanofsky, Robert R.

2010-01-01

The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

Handbook of antenna technologies

CERN Document Server

Liu, Duixian; Nakano, Hisamatsu; Qing, Xianming; Zwick, Thomas

2016-01-01

The Handbook of Antenna Technologies aims to present the rapid development of antenna technologies, particularly in the past two decades, and also showcasing the newly developed technologies and the latest applications. The handbook will provide readers with the comprehensive updated reference information covering theory, modeling and optimization methods, design and measurement, new electromagnetic materials, and applications of antennas. The handbook will widely cover not only all key antenna design issues but also fundamentals, issues related to antennas (transmission, propagation, feeding structure, materials, fabrication, measurement, system, and unique design challenges in specific applications). This handbook will benefit the readers as a full and quick technical reference with a high-level historic review of technology, detailed technical descriptions and the latest practical applications.

Consideration of neutral beam prompt loss in the design of a tokamak helicon antenna

International Nuclear Information System (INIS)

Pace, D.C.; Van Zeeland, M.A.; Fishler, B.; Murphy, C.

2016-01-01

Highlights: • Neutral beam prompt losses place appreciable power on an in-vessel tokamak antenna. • Simulations predict prompt loss power and inform protective tile design. • Experiments confirm the validity of the prompt loss simulations. - Abstract: Neutral beam prompt losses (injected neutrals that ionize such that their first poloidal transit intersects with the wall) can put appreciable power on the outer wall of tokamaks, and this power may damage the wall or other internal components. These prompt losses are simulated including a protruding helicon antenna installation in the DIII-D tokamak and it is determined that 160 kW of power will impact the antenna during the injection of a particular neutral beam. Protective graphite tiles are designed in response to this modeling and the wall shape of the installed antenna is precisely measured to improve the accuracy of these calculations. Initial experiments confirm that the antenna component temperature increases according to the amount of neutral beam energy injected into the plasma. In this case, only injection of beams that are aimed counter to the plasma current produce an appreciable power load on the outer wall, suggesting that the effect is of little concern for tokamaks featuring only co-current neutral beam injection. Incorporating neutral beam prompt loss considerations into the design of this in-vessel component serves to ensure that adequate protection or cooling is provided.

Consideration of neutral beam prompt loss in the design of a tokamak helicon antenna

Energy Technology Data Exchange (ETDEWEB)

Pace, D.C., E-mail: pacedc@fusion.gat.com; Van Zeeland, M.A.; Fishler, B.; Murphy, C.

2016-11-15

Highlights: • Neutral beam prompt losses place appreciable power on an in-vessel tokamak antenna. • Simulations predict prompt loss power and inform protective tile design. • Experiments confirm the validity of the prompt loss simulations. - Abstract: Neutral beam prompt losses (injected neutrals that ionize such that their first poloidal transit intersects with the wall) can put appreciable power on the outer wall of tokamaks, and this power may damage the wall or other internal components. These prompt losses are simulated including a protruding helicon antenna installation in the DIII-D tokamak and it is determined that 160 kW of power will impact the antenna during the injection of a particular neutral beam. Protective graphite tiles are designed in response to this modeling and the wall shape of the installed antenna is precisely measured to improve the accuracy of these calculations. Initial experiments confirm that the antenna component temperature increases according to the amount of neutral beam energy injected into the plasma. In this case, only injection of beams that are aimed counter to the plasma current produce an appreciable power load on the outer wall, suggesting that the effect is of little concern for tokamaks featuring only co-current neutral beam injection. Incorporating neutral beam prompt loss considerations into the design of this in-vessel component serves to ensure that adequate protection or cooling is provided.

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

Development of film antenna for diversity reception; Diversity taio film antenna no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Shigeta, K; Taniguchi, T; Kubota, K [Mazda Motor Corp., Hiroshima (Japan)

1997-10-01

Based on the principle of capacitance-loaded window antennas, a new film antenna construction pasting an antenna element on a defogger element printed on a rear window was found. The film antennas show high reception performance, and can be used as television diversity antennas or a VICS-FM multiplex antenna. This paper describes the antenna design concept, the antenna construction and the application to a recreational vehicle which styling is 1.3-Box wagon for the electric accessory. 2 refs., 11 figs.

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.

Design of single-layer high-efficiency transmitting phase-gradient metasurface and high gain antenna

Science.gov (United States)

Zhang, Di; Yang, Xiaoqing; Su, Piqiang; Luo, Jiefang; Chen, Huijie; Yuan, Jianping; Li, Lixin

2017-12-01

In this paper, based on rotation phase-gradient principle, a single-layer, high-efficiency transmitting metasurface is designed and applied to high-gain antenna. In the case of circularly polarized incident wave, the PCR (polarization conversions ratio) of the metasurface element is greater than 90% in the band of 9.11-10.48 GHz. The transmitting wave emerges an anomalous refraction when left-handed circularly polarized wave are incident perpendicularly to the 1D phase-gradient metasurface, which is composed of cycle arrangement of 6 units with step value of 30°. The simulated anomalous refraction angle is 40.1°, coincided with the theoretical design value (40.6°). For further application, the 2D focused metasurface is designed to enhance the antenna performance while the left-handed circularly polarized antenna is placed at the focus. The simulated max gain is increased by 12 dB (182%) and the half-power beamwidth is reduced by 74.6°. The measured results are coincided with the simulations, which indicates the antenna has high directivity. The designed single-layer transmission metasurface has advantages of thin thickness (only 1.5 mm), high efficiency and light weight, and will have important application prospects in polarization conversion and beam control.

Design of a Compact Tuning Fork-Shaped Notched Ultrawideband Antenna for Wireless Communication Application

Science.gov (United States)

Shakib, M. N.; Moghavvemi, M.; Mahadi, W. N. L.

2014-01-01

A new compact planar notched ultrawideband (UWB) antenna is designed for wireless communication application. The proposed antenna has a compact size of 0.182λ × 0.228λ × 0.018λ where λ is the wavelength of the lowest operating frequency. The antenna is comprised of rectangular radiating patch, ground plane, and an arc-shaped strip in between radiating patch and feed line. By introducing a new Tuning Fork-shaped notch in the radiating plane, a stopband is obtained. The antenna is tested and measured. The measured result indicated that fabricated antenna has achieved a wide bandwidth of 4.33–13.8 GHz (at −10 dB return loss) with a rejection frequency band of 5.28–6.97 GHz (WiMAX, WLAN, and C-band). The effects of the parameters of the antenna are discussed. The experiment results demonstrate that the proposed antenna can well meet the requirement for the UWB communication in spite of its compactness and small size. PMID:24723835

STRAP Is a Strong Predictive Marker of Adjuvant Chemotherapy Benefit in Colorectal Cancer

OpenAIRE

Buess, Martin; Terracciano, Luigi; Reuter, Jurgen; Ballabeni, Pierluigi; Boulay, Jean-Louis; Laffer, Urban; Metzger, Urs; Herrmann, Richard; Rochlitz, Christoph

2004-01-01

BACKGROUND: Molecular predictors for the effectiveness of adjuvant chemotherapy in colorectal cancer are of considerable clinical interest. To this aim, we analyzed the serine threonine receptor-associated protein (STRAP), an inhibitor of TGF-βsignaling, with regard to prognosis and prediction of adjuvant 5-FU chemotherapy benefit. i The gene copy status of STRAP was determined using quantitative realtime polymerase chain reaction in 166 colorectal tumor biopsies, which had been collected fro...

Design and Fabrication of a Reconfigurable MEMS-Based Antenna

KAUST Repository

Martinez, Miguel Angel Galicia

2011-01-01

According to the high gain obtained in a lossy silicon substrate and the compatibility of the custom MEMS process with the state of the art standard CMOS process, it is believed that the design of this antenna can lead to efficient and low cost reconfigurable millimeter-wave System-on-Chip (SoC) solution.

Mechanical design features and challenges for the ITER ICRH antenna

Energy Technology Data Exchange (ETDEWEB)

Borthwick, A. [UKAEA/Euratom Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)], E-mail: andy.borthwick@yahoo.co.uk; Agarici, G. [Fusion for Energy, Barcelona (Spain); Davis, A. [UKAEA/Euratom Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Dumortier, P.; Durodie, F. [LPP-ERM-KMS, Association EURATOM-Belgian State, Brussels (Belgium); Fanthome, J.; Hamlyn-Harris, C.; Hancock, A.D.; Lockley, D. [UKAEA/Euratom Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Mitteau, R. [Euratom-CEA Association, DSM/IRFM, CEA-Cadarache, 13108 St Paul lez Durance (France); Nightingale, M. [UKAEA/Euratom Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Sartori, R. [Fusion for Energy, Barcelona (Spain); Vulliez, K. [Euratom-CEA Association, DSM/IRFM, CEA-Cadarache, 13108 St Paul lez Durance (France)

2009-06-15

The ITER Ion Cyclotron Resonant Heating (ICRH) antenna provides plasma heating at a power of 20 MW. Operation in the ITER environment imposes significant thermal power handling capability, structural integrity, shielding and operations requirements. The design will require a step change over any predecessor in terms of power, scale and complexity. This paper reports the main mechanical design features that address the challenges and often conflicting requirements during the conceptual design phase.

Design of a remote steering antenna for ECRH heating in the stellarator Wendelstein 7-X

Energy Technology Data Exchange (ETDEWEB)

Plaum, B., E-mail: plaum@igvp.uni-stuttgart.de [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Univ. Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Lechte, C.; Kasparek, W.; Gaiser, S.; Zeitler, A. [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Univ. Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Erckmann, V. [Max-Planck-Institut für Plasmaphysik, EURATOM-IPP, D-17491 Greifswald (Germany); Weißgerber, M. [Max-Planck-Institut für Plasmaphysik, EURATOM-IPP, D-85748 Garching (Germany); Bechtold, A. [NTG Neue Technologie GmbH & Co KG, D-63571 Gelnhausen (Germany); Busch, M.; Szcepaniak, B. [Galvano-T electroplating-electroforming GmbH, D-51570 Windeck-Rosbach (Germany)

2015-10-15

Highlights: • We report about the design activities for the remote steering antennas for the stellarator W7-X. • The integration into the W7-X system and the manufacturing procedure are described. • Simulations and loss measurements for the waveguide walls were done and are in good agreement. • A method for extending the steering range is presented. • A mechanical deformation analysis showed that the deformation is not critical for the beam quality. - Abstract: For the ECRH heating system of the stellarator Wendelstein 7-X, two remote steering antennas are developed and manufactured. The principle of remote steering antennas is based on the imaging characteristics of corrugated rectangular waveguides, which is well understood and can accurately be simulated. Several details, however, require deeper investigation. The antenna needs a miter-bend and a 24 mm gap. The positions of these elements need to be chosen carefully to reduce losses and stray radiation. The antennas are manufactured from copper by electroforming. This allows to integrate all components, including the corrugated inner walls and the cooling channels, in one vacuum-tight piece. This paper reviews the design process of the remote steering antennas for W7-X as well as technological issues and experimental results from test pieces.

Design of S-Band Phased Array Antenna with High Isolation Using Broadside Coupled Split Ring Resonator

Directory of Open Access Journals (Sweden)

Sungyoun Hwang

2018-04-01

Full Text Available In this paper, a method of designing a Vivaldi type phased array antenna (PAA which operates at S-band (2.8–3.3 GHz is presented. The presented antenna uses broadside coupled split ring resonators (BC-SRRs for high isolation, wide field of view, and good active S-parameter characteristics. As an example, we design a 1 × 8 array antenna with various BC-SRR structures using theory and EM simulations. The antenna is fabricated and measured to verify the design. With the BC-SRR implemented between the two radiating elements, the isolation is shown to be enhanced by 6 dB, up to 23 dB. The scan angle is shown to be within ±53° based on a −10 dB active reflection coefficient. The operation of the scan angle is possible within ±60° with a little larger reflection coefficient (−7 dB to −8 dB. The proposed design with BC-SRRs is expected to be useful for PAA applications.

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

Computer-Automated Evolution of Spacecraft X-Band Antennas

Science.gov (United States)

Lohn, Jason D.; Homby, Gregory S.; Linden, Derek S.

2010-01-01

A document discusses the use of computer- aided evolution in arriving at a design for X-band communication antennas for NASA s three Space Technology 5 (ST5) satellites, which were launched on March 22, 2006. Two evolutionary algorithms, incorporating different representations of the antenna design and different fitness functions, were used to automatically design and optimize an X-band antenna design. A set of antenna designs satisfying initial ST5 mission requirements was evolved by use these algorithms. The two best antennas - one from each evolutionary algorithm - were built. During flight-qualification testing of these antennas, the mission requirements were changed. After minimal changes in the evolutionary algorithms - mostly in the fitness functions - new antenna designs satisfying the changed mission requirements were evolved and within one month of this change, two new antennas were designed and prototypes of the antennas were built and tested. One of these newly evolved antennas was approved for deployment on the ST5 mission, and flight-qualified versions of this design were built and installed on the spacecraft. At the time of writing the document, these antennas were the first computer-evolved hardware in outer space.

Methodology for Designing and Developing a New Ultra-Wideband Antenna Based on Bio-Inspired Optimization Techniques

Science.gov (United States)

2017-11-01

on Bio -Inspired Optimization Techniques by Canh Ly, Nghia Tran, and Ozlem Kilic Approved for public release; distribution is...Research Laboratory Methodology for Designing and Developing a New Ultra-Wideband Antenna Based on Bio -Inspired Optimization Techniques by...SUBTITLE Methodology for Designing and Developing a New Ultra-Wideband Antenna Based on Bio -Inspired Optimization Techniques 5a. CONTRACT NUMBER

Hybrid Methods in Designing Sierpinski Gasket Antennas

Directory of Open Access Journals (Sweden)

Mudrik Alaydrus

2010-12-01

Full Text Available Sierpinki gasket antennas as example of fractal antennas show multiband characteristics. The computer simulation of Sierpinksi gasket monopole with finite ground needs prohibitively large computer memory and more computational time. Hybrid methods consist of surface integral equation method and physical optics or uniform geometrical theory of diffraction should alleviate this computational burdens. The so-called full hybridization of the different methods with modifying the incoming electromagnetic waves in case of hybrid method surface integral equation method and physical optics and modification of the Greens function for hybrid method surface integral equation method and uniform geometrical theory of diffraction plays the central role in the observation. Comparison between results of different methods are given and also measurements of three Sierpinksi gasket antennas. The multiband characteristics of the antennas still can be seen with some reduction and enhancement of resonances.

The ICRF antennas for TFTR

International Nuclear Information System (INIS)

Hoffman, D.J.; Colestock, P.L.; Gardner, W.L.; Hosea, J.C.; Nagy, A.; Stevens, J.; Swain, D.W.; Wilson, J.R.

1988-01-01

Two compact loop antennas have been designed to provide ion cyclotron resonant frequency (ICRF) heating for TFTR. The antennas can convey a total of 10 MW to accomplish core heating in either high-density or high-temperature plasmas. The near-term goal of heating TFTR plasmas and the longer-term goals of ease in handling (for remote maintenance) and high reliability (in an inaccessible tritium tokamak environment) were major considerations in the antenna designs. The compact loop configuration facilitates handling because the antennas fit completely through their ports. Conservative design and extensive testing were used to attain the reliability required for TFTR. This paper summarizes how these antennas will accomplish these goals. 5 figs, 1 tab

Hybrid reflection type metasurface of nano-antennas designed for optical needle field generation

Science.gov (United States)

Wang, Shiyi; Zhan, Qiwen

2015-03-01

We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid optical antennas for comprehensive spatial engineering the properties of optical fields. Its capability is illustrated with an example to create a radially polarized vectorial beam for optical needle field generation. Functioning as local quarter-wave-plates (QWP), the MIM metasurface is designed to convert circularly polarized incident into local linear polarization to create an overall radial polarization with corresponding binary phases and desired normalized amplitude modulation ranged from 0.07 to 1. To obtain enough degrees of freedom, the optical-antenna layer comprises periodic arrangements of double metallic nano-bars with perpendicular placement and single nano-bars respectively for different amplitude modulation requirements. Both of the antennas enable to introduce π/2 retardation while reaching the desired modulation range both for phase and amplitude. Through adjusting the antennas' geometry and array carefully, we shift the gap-surface plasmon resonances facilitated by optical antennas to realize the manipulation of vectorial properties. Designed at 1064 nm wavelength, the particularly generated vectorial light output can be further tightly focused by a high numerical aperture objective to obtain longitudinally polarized flat-top focal field. The so-called optical needle field is a promising candidate for novel applications that transcend disciplinary boundaries. The proposed metasurface establishes a new class of compact optical components based on nano-scale structures, leading to compound functions for vectorial light generation.

Tunable Platform Tolerant Antenna Design for RFID and IoT Applications Using Characteristic Mode Analysis

OpenAIRE

Sharif, Abubakar; Ouyang, Jun; Yang, Feng; Long, Rui; Ishfaq, Muhammad Kamran

2018-01-01

Radio frequency identification (RFID) is a key technology to realize IoT (Internet of Things) dreams. RFID technology has been emerging in sensing, identification, tracking, and localization of goods. In order to tag a huge number of things, it is cost-effective to use one RFID antenna for tagging different things. Therefore, in this paper a platform tolerant RFID tag antenna with tunable capability is proposed. The proposed tag antenna is designed and optimized using characteristic mode anal...

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.

Convergence of the Quasi-static Antenna Design Algorithm

Science.gov (United States)

2013-04-01

was the first antenna design with quasi-static methods. In electrostatics, a perfect conductor is the same as an equipotential surface . A line of...which can cause the equipotential surface to terminate on the disk or feed wire. This requires an additional step in the solution process; the... equipotential surface is sampled to verify that the charge is enclosed by the equipotential surface . The final solution must be verified with a detailed

Design of Two Novel Dual Band-Notched UWB Antennas

Directory of Open Access Journals (Sweden)

Bing Li

2012-01-01

Full Text Available Two novel dual band-notched ultra-wideband (UWB printed monopole antennas with simple structure and small size are presented. The size of both antennas is 25×25×0.8 mm3. The bandwidth of one of the proposed antenna can be from 2.7 GHz to 36.8 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 5.14–5.94 GHz for WLAN applications. The bandwidth of the other is ranging for 2.7 to 41.1 GHz, except the bandwidth of 3.2–3.9 GHz for WiMAX applications and 4.8–5.9 GHz for WLAN applications. Bandwidths of the antennas are about 512% and 455% wider than those of conventional band-notched UWB antennas, respectively. In addition, the time-domain characteristics of the two antennas are investigated to show the difference between both antennas.

Analysis And Simulation Of Low Profile Planar Inverted - F Antenna Design For WLAN Operation In Portable Devices

Directory of Open Access Journals (Sweden)

Zaw Htet Lwin

2015-08-01

Full Text Available This paper presents a compact planar invertedF antenna PIFA design for WLAN operation in portable devices. The proposed design has size of 8 x 21 mm and provides peak directive gain of 5.78dBi with the peak return loss of -33.89dB and input impedance of 50.28amp8486. It covers a 10dB return loss bandwidth of 410MHz 2.37GHz 2.789GHz. Its VSWR varies from 1.96 to 1.93 within the antenna return loss bandwidth. As the dimension of the proposed antenna is very small the antenna is promising to be embedded within the different portable devices employing WiFi applications. This paper includes the return loss as a function of frequency with varying the different parameters VSWR input resistance radiation pattern and current distribution of the proposed antenna.

Compression and radiation of high-power short rf pulses. II. A novel antenna array design with combined compressor/radiator elements

KAUST Repository

Sirenko, Kostyantyn

2011-01-01

The paper discusses the radiation of compressed high power short RF pulses using two different types of antennas: (i) A simple monopole antenna and (ii) a novel array design, where each of the elements is constructed by combining a compressor and a radiator. The studies on the monopole antenna demonstrate the possibility of a high power short RF pulse\\'s efficient radiation even using simple antennas. The studies on the novel array design demonstrate that a reduced size array with lower pulse distortion and power decay can be constructed by assembling the array from elements each of which integrates a compressor and a radiator. This design idea can be used with any type of antenna array; in this work it is applied to a phased array.

Fluorescence Enhancement Factors on Optical Antennas: Enlarging the Experimental Values without Changing the Antenna Design

Directory of Open Access Journals (Sweden)

Jérôme Wenger

2012-01-01

Full Text Available Plasmonic antennas offer promising opportunities to control the emission of quantum objects. As a consequence, the fluorescence enhancement factor is widely used as a figure of merit for a practical antenna realization. However, the fluorescence enhancement factor is not an intrinsic property of the antenna. It critically depends on several parameters, some of which are often disregarded. In this contribution, I explore the influence of the setup collection efficiency, emitter's quantum yield, and excitation intensity. Improperly setting these parameters may significantly alter the enhancement values, leading to potential misinterpretations. The discussion is illustrated by an antenna example of a nanoaperture surrounded by plasmonic corrugations.

Theory and design of a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.

2014-03-01

For the first time, a theoretical model is presented to predict the frequency tuning of a patch antenna on a partially magnetized ferrite substrate. Both extraordinary (E) and ordinary (O) modes of the antenna are studied. The permeability tensor of the partially magnetized ferrite is calculated through the proposed theoretical model and is subsequently used to analyze the antenna\\'s performance in a microwave simulator. Prototype antennas were built, using two different bias windings, embedded in a multilayer ferrite LTCC substrate, to demonstrate E and O mode tuning. The use of embedded windings negates the requirement of bulky electromagnets, thus providing miniaturization. The concept also eliminates the demagnetization effect, thus reducing the typically required bias fields by 95%. The prototype measurements at 13 GHz demonstrate an E-mode tuning range of 10%. The proposed theoretical model has been validated by simulations and measurements. The design is highly suitable for compact, light-weight, tunable and reconfigurable microwave systems. © 1963-2012 IEEE.

TCM Analysis of Defected Ground Structures for MIMO Antenna Designs in Mobile Terminals

KAUST Repository

Ghalib, Asim; Sharawi, Mohammad S.

2017-01-01

In this paper, the theory of characteristic modes (TCM) is used for the first time to analyze the behavior of defected ground structures (DGS) when added to antenna designs. A properly designed DGS introduces currents opposite in direction

Modern lens antennas for communications engineering

CERN Document Server

Thornton, John

2012-01-01

The aim of this book is to present the modern design principles and analysis of lens antennas. It gives graduates and RF/Microwave professionals the design insights in order to make full use of lens antennas.  Why do we want to write a book in lens antennas? Because this topic has not been thoroughly publicized, its importance is underestimated. As antennas play a key role in communication systems, recent development in wireless communications would indeed benefit from the characteristics of lens antennas: low profile, and low cost etc.  The major advantages of lens antennas are na

Antennas Designed for Advanced Communications for Air Traffic Management (AC/ATM) Project

Science.gov (United States)

Zakrajsek, Robert J.

2000-01-01

The goal of the Advanced Communications for Air Traffic Management (AC/ATM) Project at the NASA Glenn Research Center at Lewis Field is to enable a communications infrastructure that provides the capacity, efficiency, and flexibility necessary to realize a mature free-flight environment. The technical thrust of the AC/ATM Project is targeted at the design, development, integration, test, and demonstration of enabling technologies for global broadband aeronautical communications. Since Ku-band facilities and equipment are readily available, one of the near-term demonstrations involves a link through a Kuband communications satellite. Two conformally mounted antennas will support the initial AC/ATM communications links. Both of these are steered electronically through monolithic microwave integrated circuit (MMIC) amplifiers and phase shifters. This link will be asymmetrical with the downlink to the aircraft (mobile vehicle) at a throughput rate of greater than 1.5 megabits per second (Mbps), whereas the throughput rate of the uplink from the aircraft will be greater than 100 kilobits per second (kbps). The data on the downlink can be narrow-band, wide-band, or a combination of both, depending on the requirements of the experiment. The AC/ATM project is purchasing a phased-array Ku-band transmitting antenna for the uplink from the test vehicle. Many Ku-band receiving antennas have been built, and one will be borrowed for a short time to perform the initial experiments at the NASA Glenn Research Center at Lewis Field. The Ku-band transmitting antenna is a 254-element MMIC phased-array antenna being built by Boeing Phantom Works. Each element can radiate 100 mW. The antenna is approximately 43-cm high by 24-cm wide by 3.3-cm thick. It can be steered beyond 60 from broadside. The beamwidth varies from 6 at broadside to 12 degrees at 60 degrees, which is typical of phased-array antennas. When the antenna is steered to 60 degrees, the beamwidth will illuminate

Design of Wideband Dual-Polarized Planar Antenna Using Multimode Concept

Directory of Open Access Journals (Sweden)

Deqiang Yang

2016-01-01

Full Text Available A wideband dual-polarized planar antenna is designed and analyzed by using the theory of characteristic modes (TCM. The eigenvalue, eigencurrent, characteristic pattern, and modal weighting coefficient are analyzed to bring physical insight to this kind of antenna. The results demonstrate that there are two modes resonant in the operating band for each polarization, which have been combined to form a wider frequency band. A bandwidth of 60.2% (1.72–3.2 GHz for VSWR < 1.5 with high isolation of 32 dB is achieved simultaneously. The size of the radiator structure is 0.33λ0 × 0.33λ0 × 0.22λ0 (λ0 refers to the center operating frequency.

Non-foster matching of an RFID antenna

KAUST Repository

Mohamed Hassan Salem, Nedime Pelin

2011-07-01

Novel designs of radio-frequency identification (RFID) tag antennas with better matching characteristics to achieve extended range for passive tags are investigated in ultra-high frequency (UHF) band. A microstrip dipole antenna with or without an integrated negative impedance converter designed to cancel out the antenna\\'s input capacitance at resonance frequency was designed, simulated, constructed and measured for implementation in RFID applications. © 2011 IEEE.

Point-to-point radio link variation at E-band and its effect on antenna design

NARCIS (Netherlands)

Al-Rawi, A.; Dubok, A.; Herben, M.H.A.J.; Smolders, A.B.

2015-01-01

Radio propagation will strongly influence the design of the antenna and front-end components of E-band point-to-point communication systems. Based on the ITU rain model, the rain attenuation is estimated in a statistical sense and it is concluded that for backhaul links of 1–10 km, antennas with a

Effect of a patellar strap on the joint position sense of the symptomatic knee in athletes with patellar tendinopathy.

Science.gov (United States)

de Vries, Astrid J; van den Akker-Scheek, Inge; Haak, Svenja L; Diercks, Ron L; van der Worp, Henk; Zwerver, Johannes

2017-11-01

The primary aim of this study was to investigate the effect of a patellar strap on the proprioception of the symptomatic leg in PT. Secondary aims were to investigate a possible difference in effectiveness between athletes with high and low proprioceptive acuity, and whether predictors of effectiveness could be found. Randomised cross-over pilot study. 24 athletes with PT (age 27.3±9.0, VISA-P 50.6±11.2) performed a joint position sense test with and without a patellar strap. The difference between both conditions was analysed using linear mixed-model analysis. No improvement in the joint position sense using the strap for the whole group was found, while those classified as having low proprioceptive acuity did improve using the strap (p=0.015, 17.2%). A larger knee girth, longer duration of symptoms and more tendon abnormalities were negatively associated with the strap's effectiveness. The use of a patellar strap improves the knee joint proprioception - measured with joint position sense - of the symptomatic leg in athletes with poor proprioceptive acuity. Especially athletes with relatively small knee girth, short duration of symptoms and small tendon abnormalities might benefit from the strap. As proprioception plays an important role in motor control, and deficits in proprioception may put an athlete at risk for (re-)injury, these findings may be relevant for prevention as well as rehabilitation purposes in those PT athletes with low proprioceptive acuity. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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.

Planar Millimeter-Wave Antennas: A Comparative Study

Directory of Open Access Journals (Sweden)

K. Pitra

2011-04-01

Full Text Available The paper describes the design and the experimental verification of three types of wideband antennas. Attention is turned to the bow-tie antenna, the Vivaldi antenna and the spiral antenna designed for the operation at millimeter waves. Bandwidth, input impedance, gain, and directivity pattern are the investigated parameters. Antennas are compared considering computer simulations in CST Microwave Studio and measured data.

Overview of ASDEX Upgrade results

DEFF Research Database (Denmark)

Kallenbach, A.; Aguiam, D.; Aho-Mantila, L.

2017-01-01

The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were design...

Inkjet printed circularly polarized antennas for GPS applications

KAUST Repository

Farooqui, Muhammad Fahad

2014-07-01

Two novel, inkjet printed circularly polarized antenna designs are presented for GPS applications. First antenna design comprises a planar monopole which has been made circularly polarized by the introduction of an L-shaped slit. The antenna shows a gain of 0.2 dBi at 1.575 GHz with 3-dB axial ratio bandwidth of 3.8%. The second antenna design comprises a modified monopole in the form of an inverted L and has been termed as circularly polarized inverted L antenna (CILA). The antenna shows a gain of -2 dBi at 1.575 GHz with 3-dB axial ratio bandwidth of 4.1%. Both the antenna designs are attractive for mobile applications.

The effect of a patellar strap on knee joint proprioception in healthy participants and athletes with patellar tendinopathy.

Science.gov (United States)

de Vries, Astrid J; van den Akker-Scheek, Inge; Diercks, Ron L; Zwerver, Johannes; van der Worp, Henk

2016-04-01

The primary aim of this study is to investigate the effect of the use of a patellar strap on knee joint proprioception in both healthy participants and in patients with patellar tendinopathy (PT). Secondary aims are to examine whether there is a difference in effectiveness of the use of a patellar strap between participants with low and high proprioceptive acuity and if possible predictors of effectiveness can be determined. Case-control. The threshold to detect passive motion with and without a patellar strap was assessed in 22 healthy participants and 21 unilateral PT patients. The results from the mixed model analysis show that in both groups of participants a small but statistically significant improvement in proprioception was found, primarily in those who had low proprioceptive acuity. A notable finding was that in the symptomatic leg of the PT group no improvement in proprioception by wearing a strap could be determined. Male gender and having fewer symptoms were possible predictors of effectiveness in PT patients. As proprioception plays a role in optimising movements and reducing load to joint-related structures like tendons and ligaments, it is considered an important protection mechanism. Although the improvements in proprioception as a result of wearing the strap are small, it might be that the use of a patellar strap can potentially play a role in injury prevention since poor proprioception can be a risk factor for (re)-injury. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Design of UWB Monopole Antenna with Dual Notched Bands Using One Modified Electromagnetic-Bandgap Structure

Science.gov (United States)

Xu, Ziqiang

2013-01-01

A modified electromagnetic-bandgap (M-EBG) structure and its application to planar monopole ultra-wideband (UWB) antenna are presented. The proposed M-EBG which comprises two strip patch and an edge-located via can perform dual notched bands. By properly designing and placing strip patch near the feedline, the proposed M-EBG not only possesses a simple structure and compact size but also exhibits good band rejection. Moreover, it is easy to tune the dual notched bands by altering the dimensions of the M-EBG. A demonstration antenna with dual band-notched characteristics is designed and fabricated to validate the proposed method. The results show that the proposed antenna can satisfy the requirements of VSWR WLAN) at 3.5 GHz and 5.5 GHz, respectively. PMID:24170984

Releveling and behavior of strap-retrofitted damaged test foundations exposed to mine subsidence

International Nuclear Information System (INIS)

Marino, G.G.

1997-01-01

Test foundation walls were constructed in an area of planned subsidence. These crawl space-sized block bearing walls were located in the tension zone of a longwall panel. The test walls were 1.2 m (40 ft) long and were vertically loaded on top with soil binds to simulate the weight of a house. As the longwall proceeded past these test foundations, subsidence movements damaged the test structures. These damaged foundations were then structurally and aesthetically repaired by using a steel strap retrofit and applying a cementitious surface coating. The repaired test foundations underwent significant subsequent subsidence as an adjacent longwall was mined beneath. The response of the repaired foundation is summarized in this paper. The steel straps were also used to relevel another set of the test foundations after they were tilted and damaged by subsidence. First, the straps were applied to the block bearing walls, and then wall jacks were used to lift the upper portion of the walls to a level position. This releveling procedure is outlined with the results

Design strategy for a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.; Shamim, Atif; Bray, Joey R.

2014-01-01

Typical microwave simulators cannot accurately predict the behavior of an antenna on a partially magnetized substrate as they assume the substrate to be in fully saturate state. In this work, a new simulation strategy aided by theoretical analysis, is presented to model a tunable patch antenna on a partially magnetized ferrite substrate through a combination of magnetostatic and microwave simulators. An antenna prototype is fabricated in Ferrite LTCC medium to verify the partially magnetized state simulations. The measured results are in close agreement with the simulations, contrary to the case where the substrate is assumed to be in saturation. The prototype designed for 13 GHz exhibits a tuning range of 10 % making it highly suitable for tunable and reconfigurable wireless applications.

Design strategy for a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.

2014-07-01

Typical microwave simulators cannot accurately predict the behavior of an antenna on a partially magnetized substrate as they assume the substrate to be in fully saturate state. In this work, a new simulation strategy aided by theoretical analysis, is presented to model a tunable patch antenna on a partially magnetized ferrite substrate through a combination of magnetostatic and microwave simulators. An antenna prototype is fabricated in Ferrite LTCC medium to verify the partially magnetized state simulations. The measured results are in close agreement with the simulations, contrary to the case where the substrate is assumed to be in saturation. The prototype designed for 13 GHz exhibits a tuning range of 10 % making it highly suitable for tunable and reconfigurable wireless applications.

A Design of 45-Degree Dual-Polarization Broadband Plane Station Antenna

Directory of Open Access Journals (Sweden)

Jianming Zhou

2015-01-01

Full Text Available A new broadband planar dual-polarization base station antenna is proposed, the antenna consists of two broadband plane coplanar base station antenna units, and so it has features of plane antenna. Two broadband plane station antenna units can, respectively, form double polarization in the direction. We analyzed the relative positions between the two antenna units and their effects on the performances of the antenna, especially for the influence of isolation. Broadband antenna has the characteristics of the broadband station antenna, and bandwidth is also guaranteed. The measured results show that the antenna can obtain 45% relative bandwidth, and 30 dB isolation degree also can be got, and the radiation performance is also good. Measurement results confirmed that the antenna gain can be guaranteed among 48% relative bandwidth, 15 dB of gain is got among bandwidth of 1.69–2.78 GHz, the isolation degree of different polarization method can reach 30 dB, and the measurement gain of two polarization methods of antenna both can reach 8.5 dBi.

Design and analysis of high gain array antenna for wireless communication applications

Directory of Open Access Journals (Sweden)

Sri Jaya LAKSHMI

2015-05-01

Full Text Available The array of antennas generally used for directing the radiated power towards a desired angular sector. Arrays can be used to synthesize a required pattern that cannot be achieved with a single element. The geometrical arrangement, number of elements, phases of the array elements and relative amplitudes depends on the angular pattern. This paper is focused on the issues related to the design and implementation of 4×1 array microstrip antenna with aperture coupled corporate feed for wireless local area network applications. Parametric analysis with change in element spacing is attempted in this work to understand the directional characteristics of the radiation pattern. Gain of more than 14 db and the efficiency more than 93% is achieved from the current design at desired frequency band.

SAR antenna design for ambiguity and multipath suppression

DEFF Research Database (Denmark)

Christensen, Erik Lintz; Dich, Mikael

1993-01-01

A high resolution airborne synthetic aperture radar (SAR) has been developed at the Electromagnetics Institute (EMI) for remote sensing applications. The paper considers the radiation of antennas for a SAR system from a systems perspective. The basic specifications of an idealised antenna...... are obtained from the required swath and the azimuth footprint needed for the SAR processing. The radiation from a real antenna causes unwanted signal returns that lead to intensity variations (multipath) and ghost echoes (ambiguity). Additional specifications are deduced by considering these signals...

Design considerations on a sparse array antenna for Ka-band spaceborne SAR applications

NARCIS (Netherlands)

Jacobs, S.; Bekers, D.; Monni, S.; Otten, M.; Van Rossum, W.; Gerini, G.; Germani, C.; Fortini, D.; Toso, G.

2015-01-01

This contribution addresses the problem of designing a sparse active array antenna for spaceborne SAR applications at Ka-band. The main driver for the design is limiting the recurring manufacturing costs associated to the number of active modules, while preserving main performance and insuring a

Contribution of LPP/ERM-KMS to the modern developments of ICRH antenna systems

Energy Technology Data Exchange (ETDEWEB)

Messiaen, A., E-mail: a.messiaen@fz-juelich.de; Ongena, J.; Dumortier, P.; Durodié, F.; Louche, F.; Ragona, R.; Vervier, M.

2016-11-15

Highlights: • Overview of ICRF antenna coupling physics, showing from first principles how to develop a state of the art ICRF system for ITER and DEMO. • Physics of conceptual solutions for the compact ITER antenna array, intended to radiate ∼10 MW/m2. • Implementing novel ideas into the matching-decoupling network of the ITER antenna array to avoid cross-coupling and to control the RF current distribution in the array. • Experimental tests of the theoretical predictions using scaled mock-ups of the ICRF antenna, including a dielectric dummy load to mimick the plasma. • Demonstrating an operational feedback control of the matching-decoupling network for the ITER antenna array, with 23 simultaneously active actuators. - Abstract: The paper gives an overview of the coupling physics of an ICRF antenna array to the plasma and of the original conceptual solutions proposed by the LPP/ERM-KMS group for the compact ITER antenna array and its matching to the RF power sources. The main contributions are (i) the use of an array of short straps grouped in triplets, (ii) the triplet feed by a four port junction and the use of a service stub to enlarge its frequency response, (iii) the multistep prematching to decrease the VSWR and minimise the voltage in the feeding transmission lines, (iv) the use of a decoupler network to neutralize the mutual coupling effects between different RF power sources and to simultaneously control the current distribution of the antenna array, (v) the various options to connect the decouplers and 3 dB hybrids for different array phasing cases in order to maintain the correct functioning of the decouplers together with load resiliency to fast variations of the plasma density in the edge (caused by e.g. pellet injection or Edge Localized Modes), (vi) the solution of the grounding problem of the ITER antenna plug-in, (vii) the test on mock-ups in front of a dielectric dummy load of the performance of the different solutions and particularly

Architectural design of a ground-based deep-space optical reception antenna

Science.gov (United States)

Kerr, E. L.

1989-01-01

An architectural design of a ground-based antenna (telescope) for receiving optical communications from deep space is presented. Physical and optical parameters, and their effect on the performance and cost considerations, are described. The channel capacity of the antenna is 100 kbits/s from Saturn and 5 Mbits/s from Mars. A novel sunshade is designed to permit optical communication even when the deep-space laser source is as close to the sun as 12 deg. Inserts in the tubes of the sunshade permit operations at solar elongations as small as 6 or 3 deg. The Nd:YAG source laser and the Fraunhofer filter (a narrow-band predetection optical filter) are tuned to match the Doppler shifts of the source and background. A typical Saturn-to-earth data link can reduce its source power requirement from 8.2 W to 2 W of laser output by employing a Fraunhofer filter instead of a conventional multilayer dielectric filter.

Modeling of compact loop antennas

International Nuclear Information System (INIS)

Baity, F.W.

1987-01-01

A general compact loop antenna model which treats all elements of the antenna as lossy transmission lines has been developed. In addition to capacitively-tuned resonant double loop (RDL) antennas the model treats stub-tuned resonant double loop antennas. Calculations using the model have been compared with measurements on full-scale mockups of resonant double loop antennas for ATF and TFTR in order to refine the transmission line parameters. Results from the model are presented for RDL antenna designs for ATF, TFTR, Tore Supra, and for the Compact Ignition Tokamak

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.

Design of an RF Antenna for a Large-Bore, High Power, Steady State Plasma Processing Chamber for Material Separation

International Nuclear Information System (INIS)

Rasmussen, D.A.; Freeman, R.L.

2001-01-01

The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC, (Contractor), and Archimedes Technology Group, (Participant) is to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure. The project objectives are to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure

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....

Millimeter-Wave Microstrip Antenna Array Design and an Adaptive Algorithm for Future 5G Wireless Communication Systems

Directory of Open Access Journals (Sweden)

Cheng-Nan Hu

2016-01-01

Full Text Available This paper presents a high gain millimeter-wave (mmW low-temperature cofired ceramic (LTCC microstrip antenna array with a compact, simple, and low-profile structure. Incorporating minimum mean square error (MMSE adaptive algorithms with the proposed 64-element microstrip antenna array, the numerical investigation reveals substantial improvements in interference reduction. A prototype is presented with a simple design for mass production. As an experiment, HFSS was used to simulate an antenna with a width of 1 mm and a length of 1.23 mm, resonating at 38 GHz. Two identical mmW LTCC microstrip antenna arrays were built for measurement, and the center element was excited. The results demonstrated a return loss better than 15 dB and a peak gain higher than 6.5 dBi at frequencies of interest, which verified the feasibility of the design concept.

The design of an ultra-thin and multiple channels optical receiving antenna system with freeform lenses

Science.gov (United States)

Zhang, Lingyun; Cheng, Dewen; Hu, Yuan; Song, Weitao; Wang, Yongtian

2014-11-01

Visible Light Communications (VLC) has become an emerging area of research since it can provide higher data transmission speed and wider bandwidth. The white LEDs are very important components of the VLC system, because it has the advantages of higher brightness, lower power consumption, and a longer lifetime. More importantly, their intensity and color are modulatable. Besides the light source, the optical antenna system also plays a very important role in the VLC system since it determines the optical gain, effective working area and transmission rate of the VLC system. In this paper, we propose to design an ultra-thin and multiple channels optical antenna system by tiling multiple off-axis lenses, each of which consists of two reflective and two refractive freeform surfaces. The tiling of multiple systems and detectors but with different band filters makes it possible to design a wavelength division multiplexing VLC system to highly improve the system capacity. The field of view of the designed antenna system is 30°, the entrance pupil diameter is 1.5mm, and the thickness of the system is under 4mm. The design methods are presented and the results are discussed in the last section of this paper. Besides the optical gain is analyzed and calculated. The antenna system can be tiled up to four channels but without the increase of thickness.

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.

Theory and design of a tunable antenna on a partially magnetized ferrite LTCC substrate

KAUST Repository

Ghaffar, Farhan A.; Bray, Joey R.; Shamim, Atif

2014-01-01

For the first time, a theoretical model is presented to predict the frequency tuning of a patch antenna on a partially magnetized ferrite substrate. Both extraordinary (E) and ordinary (O) modes of the antenna are studied. The permeability tensor of the partially magnetized ferrite is calculated through the proposed theoretical model and is subsequently used to analyze the antenna's performance in a microwave simulator. Prototype antennas were built, using two different bias windings, embedded in a multilayer ferrite LTCC substrate, to demonstrate E and O mode tuning. The use of embedded windings negates the requirement of bulky electromagnets, thus providing miniaturization. The concept also eliminates the demagnetization effect, thus reducing the typically required bias fields by 95%. The prototype measurements at 13 GHz demonstrate an E-mode tuning range of 10%. The proposed theoretical model has been validated by simulations and measurements. The design is highly suitable for compact, light-weight, tunable and reconfigurable microwave systems. © 1963-2012 IEEE.

Inflatable antenna for earth observing systems

Science.gov (United States)

Wang, Hong-Jian; Guan, Fu-ling; Xu, Yan; Yi, Min

2010-09-01

This paper describe mechanical design, dynamic analysis, and deployment demonstration of the antenna , and the photogrammetry detecting RMS of inflatable antenna surface, the possible errors results form the measurement are also analysed. Ticra's Grasp software are used to predict the inflatable antenna pattern based on the coordinates of the 460 points on the parabolic surface, the final results verified the whole design process.

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

Determination of antenna factors using a three-antenna method at open-field test site

Science.gov (United States)

Masuzawa, Hiroshi; Tejima, Teruo; Harima, Katsushige; Morikawa, Takao

1992-09-01

Recently NIST has used the three-antenna method for calibration of the antenna factor of an antenna used for EMI measurements. This method does not require the specially designed standard antennas which are necessary in the standard field method or the standard antenna method, and can be used at an open-field test site. This paper theoretically and experimentally examines the measurement errors of this method and evaluates the precision of the antenna-factor calibration. It is found that the main source of the error is the non-ideal propagation characteristics of the test site, which should therefore be measured before the calibration. The precision of the antenna-factor calibration at the test site used in these experiments, is estimated to be 0.5 dB.

Design and Verification of MIMO 2x2 Reference Antennas

DEFF Research Database (Denmark)

Szini, Istvan Janos; Pedersen, Gert Frølund; Estrada, J.

2012-01-01

The development and initial discussion of a reference MIMO 2×2 antenna concept has been presented in [1]. The reference antenna concept has been created to eliminate the uncertainties linked to the unknown antenna performance of the few LTE MIMO 2×2 reference devices or golden standards currently...... available for evaluating radiated data throughput measurement methodologies and test facilities. The proposed concept is based on simple antennas with a well-known Figure of Merit (FoM) and controllable performance. In this paper we present the recent developments on the antenna concept and report...... on the first measured performance at uniform incoming power distribution, figures and correlations between different measurement labs....

Design of a novel high efficiency antenna for helicon plasma sources

Science.gov (United States)

Fazelpour, S.; Chakhmachi, A.; Iraji, D.

2018-06-01

A new configuration for an antenna, which increases the absorption power and plasma density, is proposed for helicon plasma sources. The influence of the electromagnetic wave pattern symmetry on the plasma density and absorption power in a helicon plasma source with a common antenna (Nagoya) is analysed by using the standard COMSOL Multiphysics 5.3 software. In contrast to the theoretical model prediction, the electromagnetic wave does not represent a symmetric pattern for the common Nagoya antenna. In this work, a new configuration for an antenna is proposed which refines the asymmetries of the wave pattern in helicon plasma sources. The plasma parameters such as plasma density and absorption rate for a common Nagoya antenna and our proposed antenna under the same conditions are studied using simulations. In addition, the plasma density of seven operational helicon plasma source devices, having a common Nagoya antenna, is compared with the simulation results of our proposed antenna and the common Nagoya antenna. The simulation results show that the density of the plasma, which is produced by using our proposed antenna, is approximately twice in comparison to the plasma density produced by using the common Nagoya antenna. In fact, the simulation results indicate that the electric and magnetic fields symmetry of the helicon wave plays a vital role in increasing wave-particle coupling. As a result, wave-particle energy exchange and the plasma density of helicon plasma sources will be increased.

Design of test kits for the RF characterization of the PAM antenna of LHCD system for Aditya-upgrade Tokamak

International Nuclear Information System (INIS)

Jain, Yogesh M.; Sharma, P.K.; Parmar, P.R.; Ambulkar, K.K.

2017-01-01

The Lower Hybrid Current Drive (LHCD) system of the ADITYA-Upgrade tokamak will employ a Passive Active Multijunction (PAM) antenna to launch 250 kW of RF power at 3.7 GHz to drive plasma current non inductively in the tokamak. To evaluate the RF performance of the designed PAM antenna, it is characterized with the help of VNA measurements. The performance of the PAM antenna is mainly decided by the integrated performance of the entire antenna (with a differential phase shift of 270° and equal power distribution between each of the output waveguides) and the performance of mode converter, which transforms input TE 10 mode to TE 30 mode (with a mode purity of 98.5% at the output). This poster thus reports the design and analysis of these testing kits. Also, the test results of PAM antenna obtained by using these test kits would also be presented and discussed in this poster

Design of UWB Monopole Antenna with Dual Notched Bands Using One Modified Electromagnetic-Bandgap Structure

Directory of Open Access Journals (Sweden)

Hao Liu

2013-01-01

Full Text Available A modified electromagnetic-bandgap (M-EBG structure and its application to planar monopole ultra-wideband (UWB antenna are presented. The proposed M-EBG which comprises two strip patch and an edge-located via can perform dual notched bands. By properly designing and placing strip patch near the feedline, the proposed M-EBG not only possesses a simple structure and compact size but also exhibits good band rejection. Moreover, it is easy to tune the dual notched bands by altering the dimensions of the M-EBG. A demonstration antenna with dual band-notched characteristics is designed and fabricated to validate the proposed method. The results show that the proposed antenna can satisfy the requirements of VSWR < 2 over UWB 3.1–10.6 GHz, except for the rejected bands of the world interoperability for microwave access (WiMAX and the wireless local area network (WLAN at 3.5 GHz and 5.5 GHz, respectively.

Conformal Lightweight Antenna Structures for Aeronautical Communication Technologies

Science.gov (United States)

Meador, Mary Ann

2017-01-01

This project is to develop antennas which enable beyond line of sight (BLOS) command and control for UAVs. We will take advantage of newly assigned provisional Ku-band spectrum for UAVs and use unique antenna designs to avoid interference with ground systems. This will involve designing antennas with high isotropic effective radiated power (EIRP) and ultra-low sidelobes. The antennas will be made with polymer aerogel as a substrate to both reduce weight and improve performance, as demonstrated in an Aero Seedling. In addition, designing the antennas to be conformal to the aircraft fuselage will reduce drag.

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.

Telecommunications Antennas for the Juno Mission to Jupiter

Science.gov (United States)

Vacchione, Joseph D.; Kruid, Ronald C.; Prata, Aluizio, Jr.; Amaro, Luis R.; Mittskus, Anthony P.

2012-01-01

The Juno Mission to Jupiter requires a full sphere of coverage throughout its cruise to and mission at Jupiter. This coverage is accommodated through the use of five (5) antennas; forward facing low gain, medium gain, and high gain antennas, and an aft facing low gain antenna along with an aft mounted low gain antenna with a torus shaped antenna pattern. Three of the antennas (the forward low and medium gain antennas) are classical designs that have been employed on several prior NASA missions. Two of the antennas employ new technology developed to meet the Juno mission requirements. The new technology developed for the low gain with torus shaped radiation pattern represents a significant evolution of the bicone antenna. The high gain antenna employs a specialized surface shaping designed to broaden the antenna's main beam at Ka-band to ease the requirements on the spacecraft's attitude control system.

Millimeter-wave antennas configurations and applications

CERN Document Server

du Preez, Jaco

2016-01-01

This book comprehensively reviews the state of the art in millimeter-wave antennas, traces important recent developments and provides information on a wide range of antenna configurations and applications. While fundamental theoretical aspects are discussed whenever necessary, the book primarily focuses on design principles and concepts, manufacture, measurement techniques, and practical results. Each of the various antenna types scalable to millimeter-wave dimensions is considered individually, with coverage of leaky-wave and surface-wave antennas, printed antennas, integrated antennas, and reflector and lens systems. The final two chapters address the subject from a systems perspective, providing an overview of supporting circuitry and examining in detail diverse millimeter-wave applications, including high-speed wireless communications, radio astronomy, and radar. The vast amount of information now available on millimeter-wave systems can be daunting for researchers and designers entering the field. This b...

Smart Antenna UKM Testbed for Digital Beamforming System

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available A new design of smart antenna testbed developed at UKM for digital beamforming purpose is proposed. The smart antenna UKM testbed developed based on modular design employing two novel designs of L-probe fed inverted hybrid E-H (LIEH array antenna and software reconfigurable digital beamforming system (DBS. The antenna is developed based on using the novel LIEH microstrip patch element design arranged into 4×1 uniform linear array antenna. An interface board is designed to interface to the ADC board with the RF front-end receiver. The modular concept of the system provides the capability to test the antenna hardware, beamforming unit, and beamforming algorithm in an independent manner, thus allowing the smart antenna system to be developed and tested in parallel, hence reduces the design time. The DBS was developed using a high-performance TMS320C6711TM floating-point DSP board and a 4-channel RF front-end receiver developed in-house. An interface board is designed to interface to the ADC board with the RF front-end receiver. A four-element receiving array testbed at 1.88–2.22 GHz frequency is constructed, and digital beamforming on this testbed is successfully demonstrated.

Analysis of equivalent antenna based on FDTD method

Directory of Open Access Journals (Sweden)

Yun-xing Yang

2014-09-01

Full Text Available An equivalent microstrip antenna used in radio proximity fuse is presented. The design of this antenna is based on multilayer multi-permittivity dielectric substrate which is analyzed by finite difference time domain (FDTD method. Equivalent iterative formula is modified in the condition of cylindrical coordinate system. The mixed substrate which contains two kinds of media (one of them is airtakes the place of original single substrate. The results of equivalent antenna simulation show that the resonant frequency of equivalent antenna is similar to that of the original antenna. The validity of analysis can be validated by means of antenna resonant frequency formula. Two antennas have same radiation pattern and similar gain. This method can be used to reduce the weight of antenna, which is significant to the design of missile-borne antenna.

Development and test of decoupler for ICRF antenna in EAST

Energy Technology Data Exchange (ETDEWEB)

Chen, Gen, E-mail: chengen@ipp.ac.cn; Mao, Yuzhou; Zhao, Yanping; Yuan, Shuai; Zhang, Xinjun; Qing, Chengming

2016-06-15

Highlights: • The mechanism of decoupler for ICRF antenna is proposed. • Three candidate assembly positions for the decouper can be used. • The performance relies on the ohmic dissipation and the assembly position of decoupler. - Abstract: Ion Cyclotron Range of Frequency (ICRF) heating has been adopted in EAST tokamak as one of main auxiliary heating methods. The ICRF antenna usually consists of multiple launching elements because of limited port and space of tokamak device. Mutual coupling between straps has been observed in previous EAST ICRF current drive experiments. Due to adverse effects of such mutual coupling, many issues induced by cross power cannot be ignored, such as power imbalance in feed lines, high voltage standing wave ratio (VSWR), and etc. To restrain such mutual coupling, A device named decoupler was developed and tested in EAST ICRF system. According to the admittance matrix of load, three assembly positions (oscillation position, optimum position, and smooth position) along transmission line for the decoupler were taken into account and tested. The test results showed that ohmic dissipation in decoupler could not be neglected, which partly influenced the decoupling performance. The oscillation position and optimum position could restrain such adverse effects of ohmic dissipation and showed good decoupling performance. However, they cannot ensure the steady operation during H-mod due to the load variation. Finally, the smooth position has been adopted for EAST I port antenna because of steady decoupling performance comprised with engineering error and load resilience, which sincerely enhance the capability of system operation.

Optically Controlled Phased Array Antenna

National Research Council Canada - National Science Library

Garafalo, David

1998-01-01

.... The antenna is a 3-foot by 9 foot phased array capable of a scan angle of 120 degrees. The antenna was designed to be conformal to the cargo door of a large aircraft and is designed to operate in the frequency range of 830 - 1400 MHz with a 30...

Design of Wire Antennas by Using an Evolved Particle Swarm Optimization Algorithm

NARCIS (Netherlands)

Lepelaars, E.S.A.M.; Zwamborn, A.P.M.; Rogovic, A.; Marasini, C.; Monorchio, A.

2007-01-01

A Particle Swarm Optimization (PSO) algorithm has been used in conjunction with a full-wave numerical code based on the Method of Moments (MoM) to design and optimize wire antennas. The PSO is a robust stochastic evolutionary numerical technique that is very effective in optimizing multidimensional

An Influence Study of Hydrogen Evolution Characteristics on the Negative Strap Corrosion of Lead Acid Battery

Directory of Open Access Journals (Sweden)

Zhong Guobin

2015-01-01

Full Text Available Negative strap corrosion is an important reason for the failure of valve regulated lead acid battery. This paper selected the Pb-Sb alloy material and Pb-Sn alloy material, made an investigation on the negative corrosion resistance and hydrogen evolution of these two alloy materials by scanning electron microscope analysis, metallographic analysis, chemical study and linear sweep voltammetry, and discussed the influence of lead alloy hydrogen evolution on the negative strap corrosion. The results showed that the hydrogen evolution reaction rates of the alloys had an impact on the corrosion areas with the maximum thickness of the alloys and the depth of corrosion layers. Greater hydrogen evolution reaction rate can lead to shorter distance between the corrosion area with the maximum thickness and the liquid level; whereas the greater corrosion layer thickness can bring aggravated risk of negative strap corrosion failure.

Topology Design for Directional Range Extension Networks with Antenna Blockage

Science.gov (United States)

2017-03-19

this is equivalent to the Hamiltonian Path Problem, which is NP- hard . More work on computationally efficient topology formation and maintenance... formation and maintenance of low-degree air topologies. 1 I. INTRODUCTION Tactical military networks both on land and at sea often have restricted...constraints on the number of antenna beams that a pod can support, a string topology formation and maintenance algorithm may be the best design choice

A PIC-MCC code RFdinity1d for simulation of discharge initiation by ICRF antenna

Science.gov (United States)

Tripský, M.; Wauters, T.; Lyssoivan, A.; Bobkov, V.; Schneider, P. A.; Stepanov, I.; Douai, D.; Van Eester, D.; Noterdaeme, J.-M.; Van Schoor, M.; ASDEX Upgrade Team; EUROfusion MST1 Team

2017-12-01

Discharges produced and sustained by ion cyclotron range of frequency (ICRF) waves in absence of plasma current will be used on ITER for (ion cyclotron-) wall conditioning (ICWC, Te = 3{-}5 eV, ne 18 m-3 ). In this paper, we present the 1D particle-in-cell Monte Carlo collision (PIC-MCC) RFdinity1d for the study the breakdown phase of ICRF discharges, and its dependency on the RF discharge parameters (i) antenna input power P i , (ii) RF frequency f, (iii) shape of the electric field and (iv) the neutral gas pressure pH_2 . The code traces the motion of both electrons and ions in a narrow bundle of magnetic field lines close to the antenna straps. The charged particles are accelerated in the parallel direction with respect to the magnetic field B T by two electric fields: (i) the vacuum RF field of the ICRF antenna E_z^RF and (ii) the electrostatic field E_zP determined by the solution of Poisson’s equation. The electron density evolution in simulations follows exponential increase, {\\dot{n_e} ∼ ν_ion t } . The ionization rate varies with increasing electron density as different mechanisms become important. The charged particles are affected solely by the antenna RF field E_z^RF at low electron density ({ne < 1011} m-3 , {≤ft \\vert E_z^RF \\right \\vert \\gg ≤ft \\vert E_zP \\right \\vert } ). At higher densities, when the electrostatic field E_zP is comparable to the antenna RF field E_z^RF , the ionization frequency reaches the maximum. Plasma oscillations propagating toroidally away from the antenna are observed. The simulated energy distributions of ions and electrons at {ne ∼ 1015} m-3 correspond a power-law Kappa energy distribution. This energy distribution was also observed in NPA measurements at ASDEX Upgrade in ICWC experiments.

Design and Fabrication of High Gain Multi-element Multi-segment Quarter-sector Cylindrical Dielectric Resonator Antenna

Science.gov (United States)

Ranjan, Pinku; Gangwar, Ravi Kumar

2017-12-01

A novel design and analysis of quarter cylindrical dielectric resonator antenna (q-CDRA) with multi-element and multi-segment (MEMS) approach has been presented. The MEMS q-CDRA has been designed by splitting four identical quarters from a solid cylinder and then multi-segmentation approach has been utilized to design q-CDRA. The proposed antenna has been designed for enhancement in bandwidth as well as for high gain. For bandwidth enhancement, multi-segmentation method has been explained for the selection of dielectric constant of materials. The performance of the proposed MEMS q-CDRA has been demonstrated with design guideline of MEMS approach. To validate the antenna performance, three segments q-CDRA has been fabricated and analyzed practically. The simulated results have been in good agreement with measured one. The MEMS q-CDRA has wide impedance bandwidth (|S11|≤-10 dB) of 133.8 % with monopole-like radiation pattern. The proposed MEMS q-CDRA has been operating at TM01δ mode with the measured gain of 6.65 dBi and minimum gain of 4.5 dBi in entire operating frequency band (5.1-13.7 GHz). The proposed MEMS q-CDRA may find appropriate applications in WiMAX and WLAN band.

Multiple Antenna Systems with Inherently Decoupled Radiators

DEFF Research Database (Denmark)

Pelosi, Mauro; Knudsen, Mikael B.; Pedersen, Gert Frølund

2012-01-01

In multiple antenna systems mutual coupling needs to be minimized. We propose an alternative novel decoupling technique, investigating several multiple antenna configurations for small handsets through measurements and numerical simulations. The influence of different novel designs on performance...... metrics such as total loss, antenna isolation and envelope correlation coefficient are investigated. By varying antenna impedance bandwidth and antenna location with respect to the handset, both Planar Inverted F Antenna (PIFA) and Inverted F Antennas (IFA) were investigated in different UMTS frequency...

Integrated Solar-Panel Antenna Array for CubeSats

Science.gov (United States)

Baktur, Reyhan

2016-01-01

The goal of the Integrated Solar-Panel Antenna Array for CubeSats (ISAAC) project is to design and demonstrate an effective and efficien toptically transparent, high-gain, lightweight, conformal X-band antenna array that is integrated with the solar panels of a CubeSat. The targeted demonstration is for a Near Earth Network (NEN)radio at X-band, but the design can be easilyscaled to other network radios for higher frequencies. ISAAC is a less expensive and more flexible design for communication systemscompared to a deployed dish antenna or the existing integrated solar panel antenna design.

Heating profiles on ICRF antenna Faraday shields

International Nuclear Information System (INIS)

Taylor, D.J.; Baity, F.W.; Hahs, C.L.; Riemer, B.W.; Ryan, P.M.; Williamson, D.E.

1991-01-01

A conceptual design for an uncooled Faraday shield for the BPX ion cyclotron resonance heating (ICRH) antenna, which should withstand the proposed long-pulse operation, has been completed. A high-heat-flux, uncooled Faraday shield has also been designed for the fast-wave current drive (FWCD) antenna on D3-D. For both components, the improved understanding of the heating profiles made it possible to design for heat fluxes that would otherwise have been too close to mechanically established limits. The analytical effort is described in detail, with emphasis on the design work for the BPX ICRH antenna conceptual design and for the replacement Faraday shield for the D3-D FWCD antenna. Results of analyses are shown, and configuration issues involved in component modeling are discussed. 3 refs., 6 figs., 2 tabs

Handbook of reflector antennas and feed systems v.1 theory and design of reflectors

CERN Document Server

Sharma, Satish K; Shafai, Lotfollah

2013-01-01

This is the first truly comprehensive and most up-to-date handbook available on modern reflector antennas and feed sources for diversified space and ground applications. There has never been such an all-encompassing reflector handbook in print, and no currently available title offers coverage of such recent research developments. The Handbook consists of three volumes. Volume I provides a unique combination of theoretical underpinnings with design considerations and techniques. The need for knowledge in reflector antennas has grown steadily over the last two decades due to increased use in spa

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.

Conceptual study of an ICRH traveling-wave antenna system for low-coupling conditions as expected in DEMO

Science.gov (United States)

Ragona, R.; Messiaen, A.

2016-07-01

For the central heating of a fusion reactor ion cyclotron radio frequency heating (ICRH) is the first choice method as it is able to couple RF power to the ions without density limit. The drawback of this heating method is the problem of excitation of the magneto-sonic wave through the plasma boundary layer from the antenna located along the wall, without exceeding its voltage standoff. The amount of coupling depends on the antenna excitation and the surface admittance at the antenna output due to the plasma profile. The paper deals with the optimization of the antenna excitation by the use of sections of traveling-wave antennas (TWAs) distributed all along the reactor wall between the blanket modules. They are mounted and fed in resonant ring system(s). First, the physics of the coupling of a strap array is studied by simple models and the coupling code ANTITER II. Then, after the study of the basic properties of a TWA section, its feeding problem is solved by hybrids driving them in resonant ring circuit(s). The complete modeling is obtained from the matrices of the TWA sections connected to one of the feeding hybrid(s). The solution is iterated with the coupling code to determine the loading for a reference low-coupling ITER plasma profile. The resulting wave pattern up to the plasma bulk is derived. The proposed system is totally load resilient and allows us to obtain a very selective exciting wave spectrum. A discussion of some practical implementation problems is added.

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...

Wide-band antenna design for use in minimal-scan, microwave tomographic imaging

Science.gov (United States)

Klaser, Jacob

Microwave tomography is widely used in biomedical imaging and nondestructive evaluation of dielectric materials. A novel microwave tomography system that uses an electrically-conformable mirror to steer the incident energy for producing multi-view projection data is being developed in the Non-Destructive Evaluation Laboratory (NDEL). Such a system will have a significant advantage over existing tomography systems in terms of simplicity of design and operation, particularly when there is limited-access of the structure that is being imaged. The major components of a mirror-based tomography system are the source mirror assembly, and a receiver array for capturing the multi-view projection data. This thesis addresses the design and development of the receiver array. This imaging array features balanced, anti-podal Vivaldi antennas, which offer large bandwidth, high gain and a compact size. From the simulations, as well as the experimental results for the antenna, the return loss (S 11) is below -10dB for the range from 2.2GHz to 8.2GHz, and the gain is measured to be near 6dB. The data gathered from the receiver array is then run through MATLAB code for tomographic reconstruction using the Filtered Back-Propagation algorithm from limited-view projections. Initial results of reconstruction from the measured data shows the feasibility of the approach, but a significant challenge remains in interpolating the data for a limited number of receiving antenna elements and removing noise from the reconstructed image.

Vivaldi Antenna for RF Energy Harvesting

Directory of Open Access Journals (Sweden)

J. Schneider

2016-12-01

Full Text Available Energy harvesting is a future technology for capturing ambient energy from the environment to be recycled to feed low-power devices. A planar antipodal Vivaldi antenna is presented for gathering energy from GSM, WLAN, UMTS and related applications. The designed antenna has the potential to be used in energy harvesting systems. Moreover, the antenna is suitable for UWB applications, because it operates according to FCC regulations (3.1 – 10.6 GHz. The designed antenna is printed on ARLON 600 substrate and operates in frequency band from 0.810 GHz up to more than 12 GHz. Experimental results show good conformity with simulated performance.

Circuit model of the ITER-like antenna for JET and simulation of its control algorithms

Energy Technology Data Exchange (ETDEWEB)

Durodié, Frédéric, E-mail: frederic.durodie@rma.ac.be; Křivská, Alena [LPP-ERM/KMS, TEC Partner, Brussels (Belgium); Dumortier, Pierre; Lerche, Ernesto [LPP-ERM/KMS, TEC Partner, Brussels (Belgium); JET, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Helou, Walid [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Collaboration: EUROfusion Consortium

2015-12-10

The ITER-like Antenna (ILA) for JET [1] is a 2 toroidal by 2 poloidal array of Resonant Double Loops (RDL) featuring in-vessel matching capacitors feeding RF current straps in conjugate-T manner, a low impedance quarter-wave impedance transformer, a service stub allowing hydraulic actuator and water cooling services to reach the aforementioned capacitors and a 2nd stage phase-shifter-stub matching circuit allowing to correct/choose the conjugate-T working impedance. Toroidally adjacent RDLs are fed from a 3dB hybrid splitter. It has been operated at 33, 42 and 47MHz on plasma (2008-2009) while it presently estimated frequency range is from 29 to 49MHz. At the time of the design (2001-2004) as well as the experiments the circuit models of the ILA were quite basic. The ILA front face and strap array Topica model was relatively crude and failed to correctly represent the poloidal central septum, Faraday Screen attachment as well as the segmented antenna central septum limiter. The ILA matching capacitors, T-junction, Vacuum Transmission Line (VTL) and Service Stubs were represented by lumped circuit elements and simple transmission line models. The assessment of the ILA results carried out to decide on the repair of the ILA identified that achieving routine full array operation requires a better understanding of the RF circuit, a feedback control algorithm for the 2nd stage matching as well as tighter calibrations of RF measurements. The paper presents the progress in modelling of the ILA comprising a more detailed Topica model of the front face for various plasma Scrape Off Layer profiles, a comprehensive HFSS model of the matching capacitors including internal bellows and electrode cylinders, 3D-EM models of the VTL including vacuum ceramic window, Service stub, a transmission line model of the 2nd stage matching circuit and main transmission lines including the 3dB hybrid splitters. A time evolving simulation using the improved circuit model allowed to design and

Circuit model of the ITER-like antenna for JET and simulation of its control algorithms

Science.gov (United States)

Durodié, Frédéric; Dumortier, Pierre; Helou, Walid; Křivská, Alena; Lerche, Ernesto

2015-12-01

The ITER-like Antenna (ILA) for JET [1] is a 2 toroidal by 2 poloidal array of Resonant Double Loops (RDL) featuring in-vessel matching capacitors feeding RF current straps in conjugate-T manner, a low impedance quarter-wave impedance transformer, a service stub allowing hydraulic actuator and water cooling services to reach the aforementioned capacitors and a 2nd stage phase-shifter-stub matching circuit allowing to correct/choose the conjugate-T working impedance. Toroidally adjacent RDLs are fed from a 3dB hybrid splitter. It has been operated at 33, 42 and 47MHz on plasma (2008-2009) while it presently estimated frequency range is from 29 to 49MHz. At the time of the design (2001-2004) as well as the experiments the circuit models of the ILA were quite basic. The ILA front face and strap array Topica model was relatively crude and failed to correctly represent the poloidal central septum, Faraday Screen attachment as well as the segmented antenna central septum limiter. The ILA matching capacitors, T-junction, Vacuum Transmission Line (VTL) and Service Stubs were represented by lumped circuit elements and simple transmission line models. The assessment of the ILA results carried out to decide on the repair of the ILA identified that achieving routine full array operation requires a better understanding of the RF circuit, a feedback control algorithm for the 2nd stage matching as well as tighter calibrations of RF measurements. The paper presents the progress in modelling of the ILA comprising a more detailed Topica model of the front face for various plasma Scrape Off Layer profiles, a comprehensive HFSS model of the matching capacitors including internal bellows and electrode cylinders, 3D-EM models of the VTL including vacuum ceramic window, Service stub, a transmission line model of the 2nd stage matching circuit and main transmission lines including the 3dB hybrid splitters. A time evolving simulation using the improved circuit model allowed to design and

VAlidation STandard antennas: Past, present and future

DEFF Research Database (Denmark)

Drioli, Luca Salghetti; Ostergaard, A; Paquay, M

2011-01-01

designed for validation campaigns of antenna measurement ranges. The driving requirements of VAST antennas are their mechanical stability over a given operational temperature range and with respect to any orientation of the gravity field. The mechanical design shall ensure extremely stable electrical....../V-band of telecom satellites. The paper will address requirements for future VASTs and possible architecture for multi-frequency Validation Standard antennas....

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.

Technology of fast-wave current drive antennas

International Nuclear Information System (INIS)

Hoffman, D.J.; Baity, F.W.; Goulding, R.H.; Haste, G.R.; Ryan, P.M.; Taylor, D.J.; Swain, D.W.; Mayberry, M.J.; Yugo, J.J.

1989-01-01

The design of fast-wave current drive (FWCD) antennas combines the usual antenna considerations (e.g., the plasma/antenna interface, disruptions, high currents and voltages, and thermal loads) with new requirements for spectral shaping and phase control. The internal configuration of the antenna array has a profound effect on the spectrum and the ability to control phasing. This paper elaborates on these considerations, as epitomized by a proof-of-principle (POP) experiment designed for the DIII-D tokamak. The extension of FWCD for machines such as the International Thermonuclear Engineering Reactor (ITER) will require combining ideas implemented in the POP experiment with reactor-relevant antenna concepts, such as the folded waveguide. 6 refs., 8 figs

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.

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.

Low-SAR metamaterial-inspired printed monopole antenna

Science.gov (United States)

Hossain, M. I.; Faruque, M. R. I.; Islam, M. T.; Ali, M. T.

2017-01-01

In this paper, a low-SAR metamaterial-embedded planar monopole antenna is introduced for a wireless communication system. A printed monopole antenna is designed for modern mobile, which operates in GSM, UMTS, LTE, WLAN, and Bluetooth frequency bands. A metamaterial structure is designed to use in the mobile handset with a multi-band printed monopole antenna. The finite integration technique of the CST microwave studio is used in this study. The measurement of antenna performances is taken in an anechoic chamber, and the SAR values are measured using COMOSAR system. The results indicate that metamaterial structure leads to reduce SAR without affecting antenna performance significantly. According to the measured results, the metamaterial attachment leads to reduce 87.7% peak SAR, 68.2% 1-g SAR, and 46.78% 10-g SAR compared to antenna without metamaterial.

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.

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.

A Novel Cellular Handset Design for an Enhanced Antenna Performance and a Reduced SAR in the Human Head

Directory of Open Access Journals (Sweden)

Salah I. Al-Mously

2008-01-01

Full Text Available This paper presents a novel cellular handset design with a bottom-mounted short loaded-whip antenna. This new handset design is modeled and simulated using a finite difference time-domain (FDTD-based platform SEMCAD. The proposed handset is based on a current commercially available bar-phone type with a curvature shape, keypad positioned above the screen, and top-mounted antenna. The specific absorption rates (SARs are determined computationally in the specific anthropomorphic mannequin (SAM and anatomically correct model of a human head when exposed to the EM-field radiation of the proposed cellular handset and the handset with top-mounted antenna. The two cellular handsets are simulated to operate at both GSM standards, 900 MHz as well as 1800 MHz, having different antenna dimensions and intput power of 0.6 W and 0.125 W, respectively. The proposed human hand holding the two handset models is a semirealistic hand model consists of three tissues: skin, muscle, and bone. The simulations are conducted with handset positions based on the IEEE standard 1528-2003. The results show that the proposed handset has a significant improvement of antenna efficiency when it is hand-held close to head, as compared with the handset of top-mounted antenna. Also, the results show that a significant reduction of the induced SAR in the human head-tissues can be achieved with the proposed handset.

Three-dimensional analysis of antenna sheaths

International Nuclear Information System (INIS)

Myra, J.R.; D'Ippolito, D.A.; Ho, Y.L.

1996-01-01

The present work is motivated by the importance of r.f. sheaths in determining the antenna-plasma interaction and the sensitivity of the sheaths to the complicated three-dimensional structure of modern ion cyclotron range of frequency (ICRF) antennas. To analyze r.f. sheaths on the plasma facing regions of the launcher, we first calculate the contact points of the tokamak magnetic field lines on the surface of the antenna Faraday screen and nearby limiters for realistic three-dimensional magnetic flux surface and antenna geometries. Next, the r.f. voltage that can drive sheaths at the contact points is determined and used to assess the resulting sheath power dissipation, r.f.-driven sputtering, and r.f.-induced convective cells (which produce edge profile modification). The calculations are embodied in a computer code, ANSAT (antenna sheath analysis tool), and sample ANSAT runs are shown to highlight the physics- and geometry-dependent characteristics of the r.f. sheaths and their relationship to the antenna design. One use of ANSAT is therefore as a design tool, to assess the strengths and weaknesses of a given design with respect to critical voltage handling and edge plasma interaction issues. Additionally, examples are presented where ANSAT has been useful in the analysis and interpretation of ICRF experiments (orig.)

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.

Design of CPW-Fed Antenna with Defected Substrate for Wideband Applications

Directory of Open Access Journals (Sweden)

Amar Sharma

2016-01-01

Full Text Available A CPW-fed defected substrate microstrip antenna is proposed. The proposed antenna shows wideband applications by choosing suitable defected crown shaped substrate. Defected substrate also reduces the size of an antenna. The radiating patch of proposed antenna is taken in the form of extended U-shape. The space around the radiator is utilized by extending the ground plane on both sides of radiator. Simulation of proposed antenna is done on Ansoft’s High Frequency Structure Simulator (HFSS v. 14. Measured results are in good agreement with simulated results. The prototype is taken with dimensions 36 mm × 42 mm × 1.6 mm that achieves good return loss, constant group delay, and good radiation characteristics within the entire operating band from 4.5 to 13.5 GHz (9.0 GHz with 100% impedance bandwidth at 9.0 GHz centre frequency. Thus, the proposed antenna is applicable for C and X band applications.

DEA deformed stretchable patch antenna

International Nuclear Information System (INIS)

Jiang, X-J; Jalali Mazlouman, S; Menon, C; Mahanfar, A; Vaughan, R G

2012-01-01

A stretchable patch antenna (SPA) whose frequency is tuned by a planar dielectric elastomer actuator (DEA) is presented in this paper. This mechanically reconfigurable antenna system has a configuration resembling a pre-stretched silicone belt. Part of the belt is embedded with a layer of conductive liquid metal to form the patch antenna. Part of the belt is sandwiched between conductive electrodes to form the DEA. Electrical activation of the DEA results in a contraction of the patch antenna, and as a result, in a variation of its resonance frequency. Design and fabrication steps of this system are presented. Measurement results for deformation, resonance frequency variation and efficiency of the patch antenna are also presented. (paper)

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.

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.

COMPACT DUAL-BAND INVERTED L SHAPED MONOPOLE ANTENNA FOR WLAN APPLICATIONS

Directory of Open Access Journals (Sweden)

K Sumathi

2015-12-01

Full Text Available A highly compact and an optimized design of an Inverted L shaped printed monopole antenna with a simple compact ground plane is proposed. To make the designed antenna suitable for implantation it is embedded in FR-4 substrate and is presented. The antenna is designed for dual-band operation at 2.4GHz and 5.2GHz. It is suitable for Wireless Local Area Network (WLAN applications with return loss (S11 < -10dB. The antenna has two different resonant current paths that support two resonances at 2.44GHz and 5.18GHz (forming an F-shaped structure. The size of the antenna is 32.5mm × 19.6mm × 1.6mm. The antenna design is simulated using the tool Advanced Design System (ADS 2014. This antenna design has good return loss and radiation characteristics in both the required frequency bands. The radiation pattern obtained from the proposed antenna is an Omni directional radiation pattern in the E and H plane over the frequency ranges 2.4GHz and 5.2GHz.

Textile UWB Antenna Bending and Wet Performances

Directory of Open Access Journals (Sweden)

Mai A. R. Osman

2012-01-01

Full Text Available The vision and ideas of wearable computing systems describe future electronic systems as an integral part of our everyday clothing that provides the wearer with such intelligent personal assistants. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, ultrawideband (UWB technology and textile technology. This work aimed to make closer steps towards real wearability by investigating the possibilities of designing wearable UWB antenna where textile materials are used for the substrate as well as the conducting parts of the designed antenna. Two types of conducting materials have been used for conducting parts, while a nonconducting fabric has been used as antenna substrate material. A set of comparative results of the proposed design were presented and discussed. Moreover, effects on the return loss by means of measurements for each fabricated antenna prototype under bent and fully wet conditions were discussed in more details.

Collaboration on Modeling of Ion Bernstein Wave Antenna Array and Coupling to Plasma on Tokamak Fusion Text Reactor. Final report

International Nuclear Information System (INIS)

Intrator, T.

2000-01-01

This proposal was peer reviewed and funded as a Collaboration on ''Low Phase Speed Radio Frequency Current Drive Experiments at the Tokamak Fusion Test Reactor''. The original plans we had were to carry out the collaboration proposal by including a post doctoral scientist stationed at PPPL. In response to a 60+% funding cut, all expenses were radically pruned. The post doctoral position was eliminated, and the Principal Investigator (T. Intrator) carried out the brunt of the collaboration. Visits to TFTR enabled T. Intrator to set up access to the TFTR computing network, database, and get familiar with the new antennas that were being installed in TFTR during an up to air. One unfortunate result of the budget squeeze that TFTR felt for its last year of operation was that the experiments that we specifically got funded to perform were not granted run time on TFTR., On the other hand we carried out some modeling of the electric field structure around the four strap direct launch Ion Bernstein Wave (IBW) antenna that was operated on TFTR. This turned out to be a useful exercise and shed some light on the operational characteristics of the IBW antenna and its coupling to the plasma. Because of this turn of events, the project was renamed ''Modeling of Ion Bernstein Wave Antenna Array and Coupling to Plasma on Tokamak Fusion Test Reactor''

Fundamentals of antennas concepts and applications

CERN Document Server

Christodoulou, Christos G

2001-01-01

This tutorial explains antenna design and application for various systems, including communications, remote sensing, radar, and biomedicine. It describes basic wire and array antennas in detail and introduces other types such as reflectors, lenses, horns, Yagi, microstrip, and frequency-independent antennas. Integration issues and technical challenges are discussed. Aimed at students, engineers, researchers, and technical professionals.

Design and performance verification of a wideband scalable dual-polarized probe for spherical near-field antenna measurements

DEFF Research Database (Denmark)

Pivnenko, Sergey; Kim, Oleksiy S.; Nielsen, Jeppe Majlund

2012-01-01

A wideband scalable dual-polarized probe designed by the Electromagnetic Systems group at the Technical University of Denmark is presented. The design was scaled and two probes were manufactured for the frequency bands 1-3 GHz and 0.4-1.2 GHz. The results of the acceptance tests of the 0.4-1.2 GHz...... probe are briefly discussed. Since these probes represent so-called higher-order antennas, applicability of the recently developed higher-order probe correction technique [3] for these probes was investigated. Extensive tests were carried out for two representative antennas under test using...

Miniaturized Planar Split-Ring Resonator Antenna

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Breinbjerg, Olav

2009-01-01

on how small this antenna can be. In practice, the lower bound is set by losses in utilized materials and manufacturing inaccuracies. As an example, an antenna of ka=0.09 was designed, fabricated and tested. Although the initially fabricated antenna prototype had the input impedance of 43 ohms......, it was subsequently tuned to 50 ohms simply by cutting out the excessive arm length. This tuning technique is especially useful in practical applications, since it allows the antenna to be tuned in-place and thereby compensate for various inaccuracies as well as for an antenna environment....

Design optimization of a robust sleeve antenna for hepatic microwave ablation

International Nuclear Information System (INIS)

Prakash, Punit; Webster, John G; Deng Geng; Converse, Mark C; Mahvi, David M; Ferris, Michael C

2008-01-01

We describe the application of a Bayesian variable-number sample-path (VNSP) optimization algorithm to yield a robust design for a floating sleeve antenna for hepatic microwave ablation. Finite element models are used to generate the electromagnetic (EM) field and thermal distribution in liver given a particular design. Dielectric properties of the tissue are assumed to vary within ± 10% of average properties to simulate the variation among individuals. The Bayesian VNSP algorithm yields an optimal design that is a 14.3% improvement over the original design and is more robust in terms of lesion size, shape and efficiency. Moreover, the Bayesian VNSP algorithm finds an optimal solution saving 68.2% simulation of the evaluations compared to the standard sample-path optimization method

Compression and radiation of high-power short rf pulses. II. A novel antenna array design with combined compressor/radiator elements

KAUST Repository

Sirenko, Kostyantyn; Pazynin, Vadim L.; Sirenko, Yu K.; Bagci, Hakan

2011-01-01

The paper discusses the radiation of compressed high power short RF pulses using two different types of antennas: (i) A simple monopole antenna and (ii) a novel array design, where each of the elements is constructed by combining a compressor and a

Tunable Platform Tolerant Antenna Design for RFID and IoT Applications Using Characteristic Mode Analysis

Directory of Open Access Journals (Sweden)

Abubakar Sharif

2018-01-01

Full Text Available Radio frequency identification (RFID is a key technology to realize IoT (Internet of Things dreams. RFID technology has been emerging in sensing, identification, tracking, and localization of goods. In order to tag a huge number of things, it is cost-effective to use one RFID antenna for tagging different things. Therefore, in this paper a platform tolerant RFID tag antenna with tunable capability is proposed. The proposed tag antenna is designed and optimized using characteristic mode analysis (CMA. Moreover, this tag antenna consists of a folded patch wrapped around FR 4 substrate and a feeding loop element printed on a paper substrate. The inductive feeding loop is stacked over folded patch and it provides impedance match with RFID chip. Because of separate radiating and feeding element, this tag antenna has a versatility of impedance matching with any RFID chip. Furthermore, this tag is able to cover American RFID band (902–928 MHz and can be tuned to European RFID band (865–868 MHz by adding tunable strips. In order to demonstrate platform tolerant operation, the read range of RFID tag is measured by mounting it on different materials. The maximum read range of RFID tag is 4.5 m in free space or on dielectrics and 6.5 m above 200 × 200 mm2 metal plate, respectively.

Inkjet-Printed Ultra Wide Band Fractal Antennas

KAUST Repository

Maza, Armando Rodriguez

2012-05-01

In this work, Paper-based inkjet-printed Ultra-wide band (UWB) fractal antennas are presented. Three new designs, a combined UWB fractal monopole based on the fourth order Koch Snowflake fractal which utilizes a Sierpinski Gasket fractal for ink reduction, a Cantor-based fractal antenna which performs a larger bandwidth compared to previously published UWB Cantor fractal monopole antenna, and a 3D loop fractal antenna which attains miniaturization, impedance matching and multiband characteristics. It is shown that fractals prove to be a successful method of reducing fabrication cost in inkjet printed antennas while retaining or enhancing printed antenna performance.

Review of Large Spacecraft Deployable Membrane Antenna Structures

Science.gov (United States)

Liu, Zhi-Quan; Qiu, Hui; Li, Xiao; Yang, Shu-Li

2017-11-01

The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either parabolic or planar membrane antenna structures. For parabolic membrane antenna structures, there are five deploying and forming methods, including inflation, inflation-rigidization, elastic ribs driven, Shape Memory Polymer (SMP)-inflation, and electrostatic forming. The development and detailed comparison of these five methods are presented. Then, properties of membrane materials (including polyester film and polyimide film) for parabolic membrane antennas are compared. Additionally, for planar membrane antenna structures, frame shapes have changed from circular to rectangular, and different tensioning systems have emerged successively, including single Miura-Natori, double, and multi-layer tensioning systems. Recent advances in structural configurations, tensioning system design, and dynamic analysis for planar membrane antenna structures are investigated. Finally, future trends for large space membrane antenna structures are pointed out and technical problems are proposed, including design and analysis of membrane structures, materials and processes, membrane packing, surface accuracy stability, and test and verification technology. Through a review of large deployable membrane antenna structures, guidance for space membrane-antenna research and applications is provided.

Miniaturization of Multiple-Layer Folded Patch Antennas

DEFF Research Database (Denmark)

Zhang, Jiaying; Breinbjerg, Olav

2009-01-01

A new folded patch antenna with multiple layers was developed in this paper, by folding the patch in a proper way, and a highly miniaturized antenna can be realized. The multiple layer patch with 4-layer and 6-layer are designed and evaluated at 2.4 GHz, 915 MHz, and 415 MHz respectively. Then a 4...... layer patch is fabricated and measured to validate the design method. The theoretical analysis, design and simulations, fabrications, as well as the measurements are presented in this paper. All the results show that the folded patch antenna is a good candidate in making a highly miniaturized compact...

Efficiency Improvements of Antenna Optimization Using Orthogonal Fractional Experiments

Directory of Open Access Journals (Sweden)

Yen-Sheng Chen

2015-01-01

Full Text Available This paper presents an extremely efficient method for antenna design and optimization. Traditionally, antenna optimization relies on nature-inspired heuristic algorithms, which are time-consuming due to their blind-search nature. In contrast, design of experiments (DOE uses a completely different framework from heuristic algorithms, reducing the design cycle by formulating the surrogates of a design problem. However, the number of required simulations grows exponentially if a full factorial design is used. In this paper, a much more efficient technique is presented to achieve substantial time savings. By using orthogonal fractional experiments, only a small subset of the full factorial design is required, yet the resultant response surface models are still effective. The capability of orthogonal fractional experiments is demonstrated through three examples, including two tag antennas for radio-frequency identification (RFID applications and one internal antenna for long-term-evolution (LTE handheld devices. In these examples, orthogonal fractional experiments greatly improve the efficiency of DOE, thereby facilitating the antenna design with less simulation runs.

Thermal Loss in High-Q Antennas

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Bahramzy, Pevand; Svendsen, Simon

2014-01-01

Tunable antennas are very promising for future generations of mobile communications, where antennas are required to cover a wide range operating bands. This letter aims at characterizing the loss mechanism of tunable antennas. Tunable antennas typically exhibit a high Quality factor (Q), which ca...... lead to thermal loss due to the conductivity of the metal. The investigation shows that copper loss is non-negligible for high Q values. In the proposed design the copper loss is 2 dB, for a Q of 260 at 700 MHz....

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.

Printed MIMO antenna engineering

CERN Document Server

Sharawi, Mohammad S

2014-01-01

Wireless communications has made a huge leap during the past two decades. The multiple-input-multiple-output (MIMO) technology was proposed in the 1990's as a viable solution that can overcome the data rate limit experienced by single-input-single-output (SISO) systems. This resource is focused on printed MIMO antenna system design. Printed antennas are widely used in mobile and handheld terminals due to their conformity with the device, low cost, good integration within the device elements and mechanical parts, as well as ease of fabrication.A perfect design companion for practicing engineers

Continuous zoom antenna for mobile visible light communication.

Science.gov (United States)

Zhang, Xuebin; Tang, Yi; Cui, Lu; Bai, Tingzhu

2015-11-10

In this paper, we design a continuous zoom antenna for mobile visible light communication (VLC). In the design, a right-angle reflecting prism was adopted to fold the space optical path, thus decreasing the antenna thickness. The surface of each lens in the antenna is spherical, and the system cost is relatively low. Simulation results indicated that the designed system achieved the following performance: zoom ratio of 2.44, field of view (FOV) range of 18°-48°, system gain of 16.8, and system size of 18 mm×6  mm. Finally, we established an indoor VLC system model in a room the size of 5  m ×5  m ×3  m and compared the detection results of the zoom antenna and fixed-focus antenna obtained in a multisource communication environment, a mobile VLC environment, and a multiple-input multiple-output communication environment. The simulation results indicated that the continuous zoom antenna could realize large FOV and high gain. Moreover, the system showed improved stability, mobility, and environmental applicability.

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.

Developing novel 3D antennas using advanced additive manufacturing technology

Science.gov (United States)

Mirzaee, Milad

In today's world of wireless communication systems, antenna engineering is rapidly advancing as the wireless services continue to expand in support of emerging commercial applications. Antennas play a key role in the performance of advanced transceiver systems where they serve to convert electric power to electromagnetic waves and vice versa. Researchers have held significant interest in developing this crucial component for wireless communication systems by employing a variety of design techniques. In the past few years, demands for electrically small antennas continues to increase, particularly among portable and mobile wireless devices, medical electronics and aerospace systems. This trend toward smaller electronic devices makes the three dimensional (3D) antennas very appealing, since they can be designed in a way to use every available space inside the devise. Additive Manufacturing (AM) method could help to find great solutions for the antennas design for next generation of wireless communication systems. In this thesis, the design and fabrication of 3D printed antennas using AM technology is studied. To demonstrate this application of AM, different types of antennas structures have been designed and fabricated using various manufacturing processes. This thesis studies, for the first time, embedded conductive 3D printed antennas using PolyLactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS) for substrate parts and high temperature carbon paste for conductive parts which can be a good candidate to overcome the limitations of direct printing on 3D surfaces that is the most popular method to fabricate conductive parts of the antennas. This thesis also studies, for the first time, the fabrication of antennas with 3D printed conductive parts which can contribute to the new generation of 3D printed antennas.

Frequency-Tunable and Pattern Diversity Antennas for Cognitive Radio Applications

Directory of Open Access Journals (Sweden)

A. H. Ramadan

2014-01-01

Full Text Available Frequency-tunable microstrip antennas, for cognitive radio applications, are proposed herein. The approach is based on tuning the operating frequency of a bandpass filter that is incorporated into a wideband antenna. The integration of an open loop resonator- (OLR- based adjustable bandpass filter into a wideband antenna to transform it into a tunable filter-antenna is presented. The same technique is employed to design a cognitive radio pattern diversity tunable filter-antenna. A good agreement between the simulated and measured results for the fabricated prototypes is obtained. The radiation characteristics of each designed tunable filter-antenna are included herein.

Investigation of Flexible Textile Antennas and AMC Reflectors

Directory of Open Access Journals (Sweden)

M. Mantash

2012-01-01

Full Text Available In this paper, two different methods for fabric characterization are presented: a single frequency method and a broadband method. Felt and denim fabrics are characterized, and patch antennas are designed using these substrates to test both methods. Prototypes of the antennas on felt and denim are manufactured using conductive textile (called electrotextile aiming to obtain fully flexible antennas. The prototypes are characterized in anechoic chamber to be compared and obtain conclusions related to the characterization methods. A new dual-band hexagonal AMC reflector combinable with antennas is also proposed to improve their performance and reduce the backward radiation to the human body. A novel broadband CPW-fed monopole antenna is designed to be combined with the AMC. The resulted prototype is characterized and compared with the performance of the CPW-fed antenna alone.

Dual Polarized Monopole Patch Antennas for UWB Applications with Elimination of WLAN Signals

Directory of Open Access Journals (Sweden)

P. Kumar

2016-05-01

Full Text Available This paper presents the design, fabrication and measurement of dual polarized microstrip patch antennas for ultra wideband (UWB applications with notch at 5-6 GHz band. The proposed antenna rejects the wireless local area network (WLAN signals and work properly in the entire remaining ultra-wideband. Two antennas are designed for two different frequency bands of ultra wideband and both antennas together produce the entire ultra wideband with notch at 5-6 GHz band. The antennas are fed by a 50 coaxial probe and the entire design is optimized using CST Microwave Studio. The bandwidth of 3.1-5 GHz is achieved by the optimized design of Antenna-1 and the bandwidth of 6 -10.6 GHz is achieved by the optimized design of Antenna-2. The bandwidth of the optimized combined antenna is 3.1-10.6 GHz with elimination of the 5-6 GHz band. Both antennas are simulated, developed and measured. The simulated and measured results are presented. The two designed dual polarized antennas i.e. Antenna-1 and Antenna-2 can be used for 3.1-5 GHz band and 6-10.6 GHz band dual polarized applications, respectively, and the combined antenna structure can be used for UWB dual polarized applications with elimination of 5-6 GHz band signals.

Directional borehole antenna - Theory

International Nuclear Information System (INIS)

Falk, L.

1992-02-01

A directional antenna has been developed for the borehole radar constructed during phase 2 of the Stripa project. The new antenna can determine the azimuth of a strong reflector with an accuracy of about 3 degrees as confirmed during experiments in Stripa, although the ratio of borehole diameter to wavelength is small, about 0.03. The antenna synthesizes the effect of a loop antenna rotating in the borehole from four signals measured in turn by a stationary antenna. These signals are also used to calculate an electric dipole signal and a check sum which is used to examine the function of the system. The theory of directional antennas is reviewed and used to design an antenna consisting of four parallel wires. The radiation pattern of this antenna is calculated using transmission line theory with due regard to polarization, which is of fundamental importance for the analysis of directional data. In particular the multipole expansion of the field is calculated to describe the antenna radiation pattern. Various sources of error, e.g. the effect of the borehole, are discussed and the methods of calibrating the antenna are reviewed. The ambiguity inherent in a loop antenna can be removed by taking the phase of the signal into account. Typical reflectors in rock, e.g. fracture zones an tunnels, may be modelled as simple geometrical structures. The corresponding analysis is described and exemplified on measurements from Stripa. Radar data is nowadays usually analyzed directly on the computer screen using the program RADINTER developed within the Stripa project. An algorithm for automatic estimation of the parameters of a reflector have been tested with some success. The relation between measured radar data and external coordinates as determined by rotational indicators is finally expressed in terms of Euler angles. (au)

Analysis of the stress-deformed condition of the disassembly parabolic antenna

Science.gov (United States)

Odinets, M. N.; Kaygorodtseva, N. V.; Krysova, I. V.

2018-01-01

Active development of satellite communications and computer-aided design systems raises the problem of designing parabolic antennas on a new round of development. The aim of the work was to investigate the influence of the design of the mirror of a parabolic antenna on its endurance under wind load. The research task was an automated analysis of the stress-deformed condition of various designs of computer models of a paraboloid mirror (segmented or holistic) at modeling the exploitation conditions. The peculiarity of the research was that the assembly model of the antenna’s mirror was subjected to rigid connections on the contacting surfaces of the segments and only then the finite element grid was generated. The analysis showed the advantage of the design of the demountable antenna, which consists of cyclic segments, in front of the construction of the holistic antenna. Calculation of the stress-deformed condition of the antennas allows us to conclude that dividing the design of the antenna’s mirror on parabolic and cyclic segments increases it strength and rigidity. In the future, this can be used to minimize the mass of antenna and the dimensions of the disassembled antenna. The presented way of modeling a mirror of a parabolic antenna using to the method of the finite-element analysis can be used in the production of antennas.

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....

Experimental study of the interaction between RF antennas and the edge plasma of a tokamak

International Nuclear Information System (INIS)

Kubic, Martin

2013-01-01

Antennas operating in the ion cyclotron range of frequency (ICRF) provide a useful tool for plasma heating in many tokamaks and are foreseen to play an important role in ITER. However, in addition to the desired heating in the core plasma, spurious interactions with the plasma edge and material boundary are known to occur. Many of these deleterious effects are caused by the formation of radio-frequency (RF) sheaths. The aim of this thesis is to study, mainly experimentally, scrape-off layer (SOL) modifications caused by RF sheaths effects by means of Langmuir probes that are magnetically connected to a powered ICRH antenna. Effects of the two types of Faraday screens' operation on RF-induced SOL modifications are studied for different plasma and antenna configurations - scans of strap power ratio imbalance, injected power and SOL density. In addition to experimental work, the influence of RF sheaths on retarding field analyzer (RFA) measurements of sheath potential is investigated with one-dimensional particle-in-cell code. One-dimensional particle-in-cell simulations show that the RFA is able to measure reliably the sheath potential only for ion plasma frequencies ω π similar to RF cyclotron frequency ω rf , while for the real SOL conditions (ω π ≥ ω rf ), when the RFA is magnetically connected to RF region, it is strongly underestimated. An alternative method to investigate RF sheaths effects is proposed by using broadening of the ion distribution function as an evidence of the RF electric fields in the sheath. RFA measurements in Tore Supra indicate that RF potentials do indeed propagate from the antenna 12 m along magnetic field lines. (author) [fr

A meta-analysis into the effect of lateral-wedged insoles with subtalar strapping versus traditional insoles in adults with medial knee osteoarthritis.

Directory of Open Access Journals (Sweden)

L. Duvenhage

2011-02-01

Full Text Available To  systematically  identify,  collate,  and  analyze  the  current available evidence  for  the  effectiveness  of  lateral-wedged  insoles,  with subtalar strapping,  on  reducing  pain,  improving  function  and  improving  the femoral-tibial  angle  (FTA,  in  adults  with  medial  knee osteoarthritis compared to traditional insoles without subtalar strapping.Six computerised databases, namely Cochrane Library, CiNAHL, PEDro, BIOMED central,  PubMed  and  ScienceDirect  were  searched. The  included articles were  then  all  rated  using  the  PEDro  scale  to  determine  their meth-odological quality.  Homogeneous data were pooled in a meta-analysis using Review Manager (REVMAN software.  Where statistical pooling of the results was not possible, findings were summarised in narrative form. Three randomised controlled trials were selected for this review. The average PEDro score was 5.7. A meta-analysis demonstrated that lateral-wedged insoles with subtalar strapping significantly reduced pain in the short-term (p=0.004. The review found that lateral-wedge insoles with subtalar strapping significantly decreased pain in the short-term and seemed to have a positive effect on the FTA in the long-term, when compared to traditional insoles without  subtalar strapping. The lateral-wedge insole with subtalar strapping may provide a financially feasible adjunctive self-management treatment for knee OA and should be considered before invasive procedures such as surgery.

Resonant double loop antenna development at ORNL

International Nuclear Information System (INIS)

Taylor, D.J.; Baity, F.W.; Brown, R.A.; Bryan, W.E.; Fadnek, A.; Hoffman, D.J.; King, J.F.; Livesey, R.L.; McIlwain, R.L.

1988-01-01

As part of the development of ion cyclotron resonant heating (ICRH) systems for fusion research, Oak Ridge National Laboratory (ORNL) has built resonant double loop (RDL) antennas for the Tokamak Fusion Test Reactor (TFTR) (Princeton Plasma Physics Laboratory, Princeton, NJ, US) and Tore Supra (Centre d'Etudes Nucleaire, Cadarache, France). Each antenna has been designed to deliver 4 MW of power. The electrical circuit and the mechanical philosophy employed are the same for both antennas, but different operating environments lead to substantial differences in the designs of specific components. A description and a comparison of the technologies developed in the two designs are presented. 5 refs., 4 figs., 1 tab

A practical guide to the design and construction of a single wire beverage antenna

Science.gov (United States)

Spong, H. L.

1980-09-01

Theoretical results are presented which show the performance likely to result from using differing antenna heights, lengths and wire sizes and from operating with different ground conductivities. These studies were undertaken to provide practical advice for constructors and operators. Design parameters can be easily obtained with the aid of computer programs and an antenna can be rapidly constructed from readily available materials. Directivity can be increased by adding more elements, either in parallel or on a radial basis. A particular performance can be achieved with great latitude in the parameters. Good low angle performance can be achieved without large ground screens. A directional array can be made by switching between a number of elements set up on different bearings.

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

Aerogel-Based Antennas for Aerospace and Terrestrial Applications

Science.gov (United States)

Meador, Mary Ann (Inventor); Miranda, Felix (Inventor); Van Keuls, Frederick (Inventor)

2016-01-01

Systems and methods for lightweight, customizable antenna with improved performance and mechanical properties are disclosed. In some aspects, aerogels can be used, for example, as a substrate for antenna fabrication. The reduced weight and expense, as well as the increased ability to adapt antenna designs, permits a systems to mitigate a variety of burdens associated with antennas while providing added benefits.

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.

Spin wave propagation in perpendicular magnetized 20 nm Yttrium Iron Garnet with different antenna design

Science.gov (United States)

Chen, Jilei; Stueckler, Tobias; Zhang, Youguang; Zhao, Weisheng; Yu, Haiming; Chang, Houchen; Liu, Tao; Wu, Mingzhong; Liu, Chuanpu; Liao, Zhimin; Yu, Dapeng; Fert Beijing research institute Team; Colorado State University Team; Peking University Collaboration

Magnonics offers a new way to transport information using spin waves free of charge current and could lead to a new paradigm in the area of computing. Forward volume (FV) mode spin wave with perpendicular magnetized configuration is suitable for spin wave logic device because it is free of non-reciprocity effect. Here, we study FV mode spin wave propagation in YIG thin film with an ultra-low damping. We integrated differently designed antenna i.e., coplanar waveguide and micro stripline with different dimensions. The k vectors of the spin waves defined by the design of the antenna are calculated using Fourier transform. We show FV mode spin wave propagation results by measuring S12 parameter from vector network analyzer and we extract the group velocity of the FV mode spin wave as well as its dispersion relations.

Non-standard antennas

CERN Document Server

Le Chevalier, Francois; Staraj, Robert

2013-01-01

This book aims at describing the wide variety of new technologies and concepts of non-standard antenna systems - reconfigurable, integrated, terahertz, deformable, ultra-wideband, using metamaterials, or MEMS,  etc, and how they open the way to a wide range of applications, from personal security and communications to multifunction radars and towed sonars, or satellite navigation systems, with space-time diversity on transmit and receive. A reference book for designers  in this lively scientific community linking antenna experts and signal processing engineers.

Perturbation approach to design of circularly polarised microstrip antennas

Science.gov (United States)

Lo, Y. T.; Richards, W. F.

1981-05-01

One of the most interesting applications of microstrip antennas is its use for transmitting or receiving circularly polarized (CP) waves. A description is given of a simple but accurate method to determine the critical dimensions needed to produce circular polarization for nearly square and nearly circular microstrip antennas. Shen (1981) in connection with the determination of the proper dimensions of an elliptical patch CP microstrip antenna first expressed the modal field in terms of Mathieu functions. To avoid the complicated numerical computation of the Mathieu functions, he approximated these functions in terms of Bessel functions. It is pointed out that the computation of Mathieu functions, or their approximate expressions can be avoided altogether if a perturbation method is applied to find the resonant frequencies of the two orthogonal modes. The implementation of this approach is demonstrated.

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

A Novel Design of Frequency Reconfigurable Antenna for UWB Application

Science.gov (United States)

Yang, Xiaolin; Yu, Ziliang; Wu, Zheng; Shen, Huajiao

2016-09-01

In this paper, we present a novel frequency reconfigurable antenna which could be easily operate in a single notched-band (WiMAX (3.3-3.6 GHz)) UWB frequency band, another single notched-band (WLAN (5-6 GHz)) UWB frequency band and the dual band-notched UWB frequency band (the stopband covers the WiMAX (3.3-3.6 GHz) and WLAN (5-6 GHz)). The reconfigurability is achieved by changing the states of PIN diodes. The simulated results are in agreement well with the measured results. And the measured patterns are slightly changed with antenna reconfiguration. The proposed antenna is a good candidate for various UWB applications.

Antenna Parts and Waveguide Transmission Line of Short Pulse Radar System Design

Directory of Open Access Journals (Sweden)

M. E. Golubcov

2014-01-01

Full Text Available The main point of this research was работы являлось to create a stand to explore the application of short pulse radio signals in radar. The stand consists of antenna and waveguide elements. Each element out to guarantee operation in X-band with 10 percent working bank and 5 percent instantaneous bandwidth and the power output gotta be 1.5 kW. The form of the antenna beam patten need to be similar to cosecant pattern Side-lobe level need to be less than -25 dB. Background level got to be at least -30 dB. Wave friction, which is radiated from the antenna aperture, got to simultaneous formed in a space.As the most easily realizing variant of such antenna cutting parabolic mirror antenna with offset irradiator was chosen. The irradiator phase centre is shifted from the focal point of the paraboloid to form a cosecant pattern. Method of physical optics is used for the analysis of antennas. Calculating pattern of horn irradiator and mirror antenna which were met the requirements was received. The construction choice was limited by the preproduction possibilities, mass and dimensions. Mirror antenna consists of skeleton framing with mirroring elements which are fixing on it. Mirroring plane is multiplex and consists off rectangular planes made by hydroforming method. Antenna was tested and adjusted at the antenna darkroom after fabricating. The results were meted requirements.Besides the mirror antenna and the horn antenna waveguide elements, waveguide bends and rotating joints were calculated, manufactured and researched. All calculations included the manufacturers tolerances, technological corner R etc. As the construction base of rotating joint coaxial waveguide was chosen. The decision on the one hand: let keep the axial symmetry of excited wave at rotating part of the waveguide, on the other hand there’s no necessary to apply resonant rings, which are plug into dielectric beads for the transition from rotating ring part to

Large inflated-antenna system

Science.gov (United States)

Hinson, W. F.; Keafer, L. S.

1984-01-01

It is proposed that for inflatable antenna systems, technology feasibility can be demonstrated and parametric design and scalability (scale factor 10 to 20) can be validated with an experiment using a 16-m-diameter antenna attached to the Shuttle. The antenna configuration consists of a thin film cone and paraboloid held to proper shape by internal pressure and a self-rigidizing torus. The cone and paraboloid would be made using pie-shaped gores with the paraboloid being coated with aluminum to provide reflectivity. The torus would be constructed using an aluminum polyester composite that when inflated would erect to a smooth shell that can withstand loads without internal pressure.

Development of Electromagnetic Band Gap Structures in the Perspective of Microstrip Antenna Design

Directory of Open Access Journals (Sweden)

Md. Shahidul Alam

2013-01-01

Full Text Available Electromagnetic band gap (EBG technology has become a significant breakthrough in the radio frequency (RF and microwave applications due to their unique band gap characteristics at certain frequency ranges. Since 1999, the EBG structures have been investigated for improving performances of numerous RF and microwave devices utilizing the surface wave suppression and the artificial magnetic conductor (AMC properties of these special type metamaterial. Issues such as compactness, wide bandwidth with low attenuation level, tunability, and suitability with planar circuitry all play an important role in the design of EBG structures. Remarkable efforts have been undertaken for the development of EBG structures to be compatible with a wide range of wireless communication systems. This paper provides a comprehensive review on various EBG structures such as three-, two-, and one-dimensional (3D, 2D, and 1D EBG, mushroom and uniplanar EBG, and their successive advancement. Considering the related fabrication complexities, implementation of vialess EBG is an attractive topic for microwave engineers. For microstrip antennas, EBG structures are used in diversified ways, which of course found to be effective except in some cases. The EBG structures are also successfully utilized in antenna arrays for reducing the mutual coupling between elements of the array. Current challenges and limitations of the typical microstrip antennas and different EBG structures are discussed in details with some possible suggestions. Hopefully, this survey will guide to increasing efforts towards the development of more compact, wideband, and high-efficient uniplanar EBG structures for performance enhancement of antenna and other microwave devices.

SKB - PNC. Development of tunnel radar antennas

International Nuclear Information System (INIS)

Falk, L.

1991-07-01

Tunnel antennas for the RAMAC borehole radar system have been developed and tested in the field. The antennas are of the loaded dipole type and the receiver and transmitter electronics have been rebuilt to screen them from the antennas. A series of measurements has demonstrated that the radar pulse is short and well shaped and relatively free from ringing, even compared with the existing borehole antennas. Two antenna sets were tested: one centered at 60 MHz and another above 100 MHz. Both produced excellent radar pictures when tested in tunnels in Stripa mine. The antennas have been designed to be easy to carry, since the signal quality often depends on the way the antenna is held relative to electric conductors in the tunnels. (au) (46 figs., 57 refs.)

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.

Multi-band Monopole Antennas Loaded with Metamaterial TL

Science.gov (United States)

Song, Zhi-jie; Liang, Jian-gang

2015-05-01

A novel metamaterial transmission line (TL) by loading complementary single Archimedean spiral resonator pair (CSASRP) is investigated and used to design a set of multi-frequency monopole antennas. The particularity is that the CSASRP which features dual-shunt branches in the equivalent circuit model is directly etched in the signal strip. By smartly controlling the element parameters, three antennas are designed and one of them covering UMTS and Bluetooth bands is fabricated and measured. The antenna exhibits impedance matching better than -10 dB and normal monopolar radiation patterns at working bands of 1.9-2.22 and 2.38-2.5 GHz. Moreover, the loaded element also contributes to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. The proposed antenna is also more compact over previous designs.

Computer-automated evolution of an X-band antenna for NASA's Space Technology 5 mission.

Science.gov (United States)

Hornby, Gregory S; Lohn, Jason D; Linden, Derek S

2011-01-01

Whereas the current practice of designing antennas by hand is severely limited because it is both time and labor intensive and requires a significant amount of domain knowledge, evolutionary algorithms can be used to search the design space and automatically find novel antenna designs that are more effective than would otherwise be developed. Here we present our work in using evolutionary algorithms to automatically design an X-band antenna for NASA's Space Technology 5 (ST5) spacecraft. Two evolutionary algorithms were used: the first uses a vector of real-valued parameters and the second uses a tree-structured generative representation for constructing the antenna. The highest-performance antennas from both algorithms were fabricated and tested and both outperformed a hand-designed antenna produced by the antenna contractor for the mission. Subsequent changes to the spacecraft orbit resulted in a change in requirements for the spacecraft antenna. By adjusting our fitness function we were able to rapidly evolve a new set of antennas for this mission in less than a month. One of these new antenna designs was built, tested, and approved for deployment on the three ST5 spacecraft, which were successfully launched into space on March 22, 2006. This evolved antenna design is the first computer-evolved antenna to be deployed for any application and is the first computer-evolved hardware in space.

Increased operational range for implantable UHF RFID antennas

NARCIS (Netherlands)

Dubok, A.; Smolders, A.B.

2014-01-01

This paper discusses the main design challenges of implantable UHF RFID antennas in lossy environments. A novel cylindrical implantable antenna concept is presented. The proposed antenna shows good performance inside lossy environments, like a human body. The RFID tag is able to work in a range up

Reconfigurable antenna using plasma reflector

Science.gov (United States)

Jusoh, Mohd Taufik; Ahmad, Khairol Amali; Din, Muhammad Faiz Md; Hashim, Fakroul Ridzuan

2018-02-01

This paper presents the feasibility study and design of plasma implementation in industrial, scientific and medical (ISM) communication band. A reflector antenna with rounded shaped is proposed to collimate beam in particular direction radiated by a quarter wave antenna operating at 2.4GHz. The simulations result has shown that by using plasma as the reflector elements, the gain, directivity and radiation patterns are identical with metal elements with only small different in the broadside direction. The versatility of the antenna is achievable by introducing electrical reconfigurable option to change the beam pattern.

Phase shifter for antenna beam steering

Energy Technology Data Exchange (ETDEWEB)

Jindal, Ravi, E-mail: rjindal21@gmail.com [Master’s(MS) in System Electronics and General Electrical, Ecole Polytechnique of university of Nantes France, IETR, Nantes (France); Razban, Tchanguiz, E-mail: tchanguiz.razban-haghighi@univ-nantes.fr [Electronics and Telecommunication Institute of Rennes (IETR-UMR 6164), Ecole Polytechnique of university of Nantes France, IETR, Nantes (France)

2016-03-09

Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

Phase shifter for antenna beam steering

International Nuclear Information System (INIS)

Jindal, Ravi; Razban, Tchanguiz

2016-01-01

Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

Remoting alternatives for a multiple phased-array antenna network

Science.gov (United States)

Shi, Zan; Foshee, James J.

2001-10-01

Significant improvements in technology have made phased array antennas an attractive alternative to the traditional dish antenna for use on wide body airplanes. These improvements have resulted in reduced size, reduced cost, reduced losses in the transmit and receive channels (simplifying the design), a significant extension in the bandwidth capability, and an increase in the functional capability. Flush mounting (thus reduced drag) and rapid beam switching are among the evolving desirable features of phased array antennas. Beam scanning of phased array antennas is limited to +/-45 degrees at best and therefore multiple phased array antennas would need to be used to insure instantaneous communications with any ground station (stations located at different geographical locations on the ground) and with other airborne stations. The exact number of phased array antennas and the specific installation location of each antenna on the wide body airplane would need to be determined by the specific communication requirements, but it is conceivable as many as five phased array antennas may need to be used to provide the required coverage. Control and switching of these antennas would need to be accomplished at a centralized location on the airplane and since these antennas would be at different locations on the airplane an efficient scheme of remoting would need to be used. To save in cost and keep the phased array antennas as small as possible the design of the phased array antennas would need to be kept simple. A dish antenna and a blade antenna (small size) could also be used to augment the system. Generating the RF signals at the central location and then using RF cables or waveguide to get the signal to any given antenna could result in significant RF losses. This paper will evaluate a number of remoting alternatives to keep the system design simple, reduce system cost, and utilize the functional capability of networking multiple phased array antennas on a wide body

Time-Zone-Pattern Satellite Broadcasting Antenna

Science.gov (United States)

Galindo, Victor; Rahmat-Samii, Yahya; Imbriale, William A.; Cohen, Herb; Cagnon, Ronald R.

1988-01-01

Direct-broadcast satellite antenna designs provide contoured beams to match four time zones in 48 contiguous states and spot beams for Alaska, Hawaii, and Puerto Rico presented in 29-page report. Includes descriptions of procedures used to arrive at optimized designs. Arrangements, amplitudes, and phases of antenna feeds presented in tables. Gain contours shown graphically. Additional tables of performance data given for cities in service area of Eastern satellite.

Antenna-load interactions at optical frequencies: impedance matching to quantum systems.

Science.gov (United States)

Olmon, R L; Raschke, M B

2012-11-09

The goal of antenna design at optical frequencies is to deliver optical electromagnetic energy to loads in the form of, e.g., atoms, molecules or nanostructures, or to enhance the radiative emission from such structures, or both. A true optical antenna would, on a qualitatively new level, control the light-matter interaction on the nanoscale for controlled optical signal transduction, radiative decay engineering, quantum coherent control, and super-resolution microscopy, and provide unprecedented sensitivity in spectroscopy. Resonant metallic structures have successfully been designed to approach these goals. They are called optical antennas in analogy to radiofrequency (RF) antennas due to their capability to collect and control electromagnetic fields at optical frequencies. However, in contrast to the RF, where exact design rules for antennas, waveguides, and antenna-load matching in terms of their impedances are well established, substantial physical differences limit the simple extension of the RF concepts into the optical regime. Key distinctions include, for one, intrinsic material resonances including quantum state excitations (metals, metal oxides, semiconductor homo- and heterostructures) and extrinsic resonances (surface plasmon/phonon polaritons) at optical frequencies. Second, in the absence of discrete inductors, capacitors, and resistors, new design strategies must be developed to impedance match the antenna to the load, ultimately in the form of a vibrational, electronic, or spin excitation on the quantum level. Third, there is as yet a lack of standard performance metrics for characterizing, comparing and quantifying optical antenna performance. Therefore, optical antenna development is currently challenged at all the levels of design, fabrication, and characterization. Here we generalize the ideal antenna-load interaction at optical frequencies, characterized by three main steps: (i) far-field reception of a propagating mode exciting an antenna

Design and Development of Compact Microstrip Patch Antenna for Wireless Applications

Directory of Open Access Journals (Sweden)

R. Nagendra

2017-09-01

Full Text Available In this paper, a novel dual band microstrip patch antenna based on composite patch antenna and radiating part. By selecting a suitable offset feed position, it is feasible to provide 50Ω characteristic impedance and thus making better impedance matching. The proposed antenna has been improved broader bandwidth by using RT Duroid substrate. The radiating part is plays a important role in creating a lower operating band (2.45 GHz in addition to achieve miniaturization. The proposed antenna has to be fabricated with RT / Duroid substrate and dimensions of 19 × 22 × 0.8 mm. The measured -10 dB bandwidth of 200 MHz at 2.45 GHz and 990 MHz at 5.45 GHz, which is quite useful for Industrial, Scientific and Medical (ISM and WLAN applications.

Compact super-wideband optical antenna

Science.gov (United States)

Wang, Wen C.; Forber, Richard; Bui, Kenneth

2009-05-01

We present progress on advanced optical antennas, which are compact, small size-weight-power units capable to receive super wideband radiated RF signals from 30 MHz to over 3 GHz. Based on electro-optical modulation of fiber-coupled guided wave light, these dielectric E-field sensors exhibit dipole-like azimuthal omni directionality, and combine small size (channels, and high EO sensing materials. The antenna system photonic link consists of a 1550 nm PM fiber-pigtailed laser, a specialized optical modulator antenna in channel waveguide format, a wideband photoreceiver, and optical phase stabilizing components. The optical modulator antenna design employs a dielectric (no electrode) Mach-Zehnder interferometer (MZI) arranged so that sensing RF bandwidth is not limited by optical transit time effects, and MZI phase drift is bias stabilized. For a prototype optical antenna system that is < 100 in3, < 10 W, < 5 lbs, we present test data on sensitivity (< 20 mV/m-Hz1/2), RF bandwidth, and antenna directionality, and show good agreement with theoretical predictions.

A high-gain high-power L-band antenna for field test applications

Science.gov (United States)

Abe, David K.; Tran, George T.; Knop, C. M.

1995-09-01

A high-gain, prime-focus parabolic dish antenna system was designed and constructed for experimental use in the field. The antenna was designed to radiate in L-band at peak power levels exceeding 1 X 106 watts. A 3.6 m diameter, commercial off-the-shelf parabolic dish antenna was modified with a custom-designed waveguide horn feed. The system was mounted on an antenna pedestal to allow for fine (approximately 0.001 degrees) elevation and azimuth control; the antenna and pedestal were mounted on a 4.3 m long trailer for mobility in the field. The antenna has a measured gain of 32 dBi and a 3-dB beamwidth of approximately 4.5 degrees. The system was successfully operated in the field in L-band at peak power levels exceeding 5 MW. The design, calibration, and testing of the antenna system will be presented.

Deployable auxetic shape memory alloy cellular antenna demonstrator: design, manufacturing and modal testing

International Nuclear Information System (INIS)

Jacobs, S; Coconnier, C; DiMaio, D; Scarpa, F; Martinez, J; Toso, M

2012-01-01

This work describes the design, manufacturing and testing of a deployable antenna for deep-space missions based on a hybrid honeycomb truss made of shape memory alloy (SMA). The deployable characteristics are enhanced by the equivalent auxetic (negative Poisson’s ratio) behaviour of the cellular configuration. Specific emphasis is placed on the modal analysis techniques used to test the lightweight SMA structure. (paper)

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.

Thermally-Activated, Delayed Fluorescence in O,B,O- and N,B,O-Strapped Boron Dipyrromethene Derivatives.

Science.gov (United States)

Stachelek, Patrycja; Alsimaree, Abdulrahman A; Alnoman, Rua B; Harriman, Anthony; Knight, Julian G

2017-03-16

A small series of boron dipyrromethene (BODIPY) dyes has been synthesized whereby the boron atom is constrained in a five-membered ring formed from either o-dihydroxypyridine or o-aminophenol. In the latter case, the amino group has been converted into the corresponding amide derivative so as to curtail the possibility for light-induced charge transfer from strap to BODIPY. These compounds are weakly emissive in fluid solution but cleavage of the strap, by treatment with a photoacid generator, restores strong fluorescence. Surprisingly, the same compounds remain weakly fluorescent in a rigid glass at 80 K where light-induced charge transfer is most unlikely. In fluid solution, the fluorescence quantum yield increases with increasing temperature due to a thermally activated step but does not correlate with the thermodynamics for intramolecular charge transfer. It is proposed that the strap causes rupture of the potential energy surface for the excited state, creating traps that provide new routes by which the wave packet can return to the ground state. Access to the trap from the excited state is reversible, leading to the delayed emission. Analysis of the temperature dependent emission intensities allows estimation of the kinetic parameters associated with entering and leaving the trap.

Non-foster matching of an RFID antenna

KAUST Repository

Mohamed Hassan Salem, Nedime Pelin; Niver, Edip

2011-01-01

Novel designs of radio-frequency identification (RFID) tag antennas with better matching characteristics to achieve extended range for passive tags are investigated in ultra-high frequency (UHF) band. A microstrip dipole antenna with or without

Inkjet printed circularly polarized antennas for GPS applications

KAUST Repository

Farooqui, Muhammad Fahad; Shamim, Atif

2014-01-01

gain of 0.2 dBi at 1.575 GHz with 3-dB axial ratio bandwidth of 3.8%. The second antenna design comprises a modified monopole in the form of an inverted L and has been termed as circularly polarized inverted L antenna (CILA). The antenna shows a gain

Resonant Frequency Calculation and Optimal Design of Peano Fractal Antenna for Partial Discharge Detection

Directory of Open Access Journals (Sweden)

Jian Li

2012-01-01

Full Text Available Ultra-high-frequency (UHF approaches have caught increasing attention recently and have been considered as a promising technology for online monitoring partial discharge (PD signals. This paper presents a Peano fractal antenna for UHF PD online monitoring of transformer with small size and multiband. The approximate formula for calculating the first resonant frequency of the Peano fractal antenna is presented. The results show that the first resonant frequency of the Peano fractal antenna is smaller than the Hilbert fractal antenna when the outer dimensions are equivalent approximately. The optimal geometric parameters of the antenna were obtained through simulation. Actual PD experiments had been carried out for two typically artificial insulation defect models, while the proposed antenna and the existing Hilbert antenna were both used for the PD measurement. The experimental results show that Peano fractal antenna is qualified for PD online UHF monitoring and a little more suitable than the Hilbert fractal antenna for pattern recognition by analyzing the waveforms of detected UHF PD signals.

The new JET phased ICRH array: first experiments and modelling

Energy Technology Data Exchange (ETDEWEB)

Bures, M; Bhatnagar, V; Brown, T; Fechner, B; Gormezano, C; Kaye, A; Lennholm, M; Righi, E; Rimini, F; Sibley, A; Start, D; Wade, T [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Goulding, R [Oak Ridge National Lab., TN (United States); Lamalle, P [Ecole Royale Militaire, Brussels (Belgium). Lab. de Physique des Plasmas; Nguyen, F [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France)

1994-07-01

New ICRH antennas on JET were designed to couple to the new JET divertor plasma configurations and to improve the Fast Wave Current Drive (FWCD) capabilities. The A2 antenna consists of 4 straps whose currents can be phased at arbitrary angles. The real time automatic tuning acts on frequency, line length (line phase shifters) and stub length. Provision is made for the coupling resistance/plasma position feedback to accommodate the fast changes in antenna loading. The first coupling, tuning and heating results are reported in 0{pi}0{pi}, 0000 and 00{pi}{pi} phasing. A new antenna model is described, which was developed to simulate the measured antenna loading in terms of plasma parameters and to provide a starting point for the real time automatic tuning. 5 refs., 4 figs.

PROSPECTS FOR THE DEVELOPMENT OF PHASED ANTENNA ARRAYS

Directory of Open Access Journals (Sweden)

A. P. Dzuba

2013-01-01

Full Text Available This article describes the main achievements in the development of phased antenna arrays (par in the past decade. Provides an overview of the most famous systems based on the PAR and PAR based on MMIC technology - PAR in radar stations, PAR to control the laser and optical beams. The existing options for the design of the PAR:ferroelectric antenna array; plasma antenna with electronic scanning; reflective grating on 100-mm semiconductor wafers; wideband antenna arrays with aperture; antenna arrays with digital beam forming.

10 GHz microstrip spanar antennas: an experimental analysis

International Nuclear Information System (INIS)

Othman, Mohd Azlishah; Azman, Hazwani; Husain, Mohd Nor; Aziz, Mohamad Zoinol Abidin Abd; Rahim, Yahaya Abd; Pee, Ahmad Nairn Che; Motsidi, Mohamad Radzi; Othman, Mohd Fairuz Iskandar

2014-01-01

This paper presents Spanar Antenna designed using CST Microwave Studio Simulation 2011. The proposed antenna was designed to operate at 10 GHz, which suggested return loss, S 11 must be less than -10 dB and voltage standing wave ratio (VSWR) must be less than 2. The best performance of simulation of Spanar Antenna was obtained at a small size of 24.8 mm × 8.0 mm with dimension board of FR4 substrate 31.7 mm × 18.5 mm. The thickness (h) and dielectric constant (εr) of substrate were 1.6 mm and 4.7. An analysis between simulation result and measurement result has been compared in order to see the antenna performance.

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)

Numerical Simulation of Plasma Antenna with FDTD Method

International Nuclear Information System (INIS)

Chao, Liang; Yue-Min, Xu; Zhi-Jiang, Wang

2008-01-01

We adopt cylindrical-coordinate FDTD algorithm to simulate and analyse a 0.4-m-long column configuration plasma antenna. FDTD method is useful for solving electromagnetic problems, especially when wave characteristics and plasma properties are self-consistently related to each other. Focus on the frequency from 75 MHz to 400 MHz, the input impedance and radiation efficiency of plasma antennas are computed. Numerical results show that, different from copper antenna, the characteristics of plasma antenna vary simultaneously with plasma frequency and collision frequency. The property can be used to construct dynamically reconBgurable antenna. The investigation is meaningful and instructional for the optimization of plasma antenna design

Numerical simulation of plasma antenna with FDTD method

International Nuclear Information System (INIS)

Liang Chao; Xu Yuemin; Wang Zhijiang

2008-01-01

We adopt cylindrical-coordinate FDTD algorithm to simulate and analyse a 0.4-m-long column configuration plasma antenna. FDTD method is useful for solving electromagnetic problems, especially when wave characteristics and plasma properties are self-consistently related to each other. Focus on the frequency from 75 MHz to 400 MHz, the input impedance and radiation efficiency of plasma antennas are computed. Numerical results show that, different from copper antenna, the characteristics of plasma antenna vary simultaneously with plasma frequency and collision frequency. The property can be used to construct dynamically reconfigurable antenna. The investigation is meaningful and instructional for the optimization of plasma antenna design. (authors)

Cirlularly Polarized Proximity- Fed Microstrip Array Antenna for LAPAN TUBSAT Micro Satellite System

Directory of Open Access Journals (Sweden)

Endra Wijaya

2013-11-01

Full Text Available The design microstrip of array antenna circular polarization characteristic developed for support LAPAN TUBSAT micro satellite system. The antenna on the micro satellite systems transmit data to ground stations operating at S band frequencies.The antenna is designed for impedance matching at frequencies of 2:25 GHz.The four elements of the square patch antenna array composed using linear methods, where the design of the transmission lines used by federal corporate structure model network consisting of three elements of the quarter wave transformer of a power divider. The feeding techniques for antenna designed using proximity coupling method, which for the type of substrate material used is similar. Circularly polarized antenna characteristics are influenced by the truncated corner pieces on the patch. To design the overall antenna used simulated method of moments in microwave office software applications. The results of measurements and simulations obtained antenna parameters, such as: bandwidth of return loss under 10 dB is 200 MHz (shifted 35%, bandwidth of axial ratio under 3dB is 1.7% and maximum gain directivity is 9 dB. Overall results obtained antenna parameters to meet the specifications of LAPAN TUBSAT micro satellite system.

Wide-scan dielectric dome antenna with reduced profile

NARCIS (Netherlands)

Gandini, E.; Silvestri, F.; Benini, A.; Gerini, G.; Martini, E.; Maci, S.; Viganò, M.C.; Toso, G.; Monni, S.

2017-01-01

In this contribution, a dielectric dome antenna design in Ka-band is presented. The dome antenna is based on the combination of a phased array and a dielectric lens. The goal of the combination of these structures is to enlarge the field of view of the antenna. In particular, the array is considered

Planar C-Band Antenna with Electronically Controllable Switched Beams

Directory of Open Access Journals (Sweden)

Mariano Barba

2009-01-01

Full Text Available The design, manufacturing, and measurements of a switchable-beam antenna at 3.5 GHz for WLL or Wimax base station antennas in planar technology are presented. This antenna performs a discrete beam scan of a 60∘ sector in azimuth and can be easily upgraded to 5 or more steps. The switching capabilities have been implemented by the inclusion of phase shifters based on PIN diodes in the feed network following a strategy that allows the reduction of the number of switches compared to a classic design. The measurements show that the design objectives have been achieved and encourage the application of the acquired experience in antennas for space applications, such as X-band SAR and Ku-band DBS.

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.

Self-Resonant Electrically Small Loop Antennas for Hearing-Aids Application

DEFF Research Database (Denmark)

Zhang, Jiaying; Breinbjerg, Olav

2010-01-01

Two novel self-resonant electrically small antennas are proposed in this paper, which are designed for hearing aids applications. They are miniaturized by using the capacitive and inductive coupling mechanism between two loops, and the antenna impedance can be matched to a specific value without...... using any additional matching network and lumped components. The dimension of the proposed antenna is 0.10λ0×0.03λ0, and it is designed to be resonant at 900 MHz. Both the analytical model and numerical simulations are discussed and explained. The antenna is also fabricated and measured in an anechoic...... chamber. The measurement methods for electrically small antennas are reported....

Optimization of wearable microwave antenna with simplified electromagnetic model of the human body

Science.gov (United States)

Januszkiewicz, Łukasz; Barba, Paolo Di; Hausman, Sławomir

2017-12-01

In this paper the problem of optimization design of a microwave wearable antenna is investigated. Reference is made to a specific antenna design that is a wideband Vee antenna the geometry of which is characterized by 6 parameters. These parameters were automatically adjusted with an evolution strategy based algorithm EStra to obtain the impedance matching of the antenna located in the proximity of the human body. The antenna was designed to operate in the ISM (industrial, scientific, medical) band which covers the frequency range of 2.4 GHz up to 2.5 GHz. The optimization procedure used the finite-difference time-domain method based full-wave simulator with a simplified human body model. In the optimization procedure small movements of antenna towards or away of the human body that are likely to happen during real use were considered. The stability of the antenna parameters irrespective of the movements of the user's body is an important factor in wearable antenna design. The optimization procedure allowed obtaining good impedance matching for a given range of antenna distances with respect to the human body.

Modified Vivaldi antenna with improved gain and phase center stability

DEFF Research Database (Denmark)

Zhang, Shuai

2016-01-01

A modified Vivaldi antenna is proposed with improved gain and phase centre stability. By applying a high permittivity dielectric substrate, the realized gain is enlarged while maintaining the compactness of the designed antenna. With a redistributed comb-shape corrugation the phase centre stabili...... of the antenna is significantly improved. The designed modified Vivaldi antenna covers the lower UWB band of 3.1-5 GHz with a realized gain higher than 10 dBi. A stable phase centre and radiation patterns over the operating band are realized....

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...

3D-Spiral Small Antenna Design and Realization for Biomedical Telemetry in the MICS band

Directory of Open Access Journals (Sweden)

A. K. Skrivervik

2009-12-01

Full Text Available This work presents the design and realization procedure of small implantable antenna for biotelemetry applications. The radiator occupies a volume smaller than 3 cm3 (without its biocompatible insulation, is well matched within the Medical Implanted Communications System band and shows an adequate gain (-28.5 dB while introduced in the appropriate equivalent body medium. The latter is a homogeneous phantom with muscle dielectric properties. A prototype has been manufactured and measurements agree with theoretical predictions. Particular attention is paid to the building requirements such as the presence of glue. Specific Absorption Rate (SAR distribution has been computed evaluating the maximum power deliverable to the antenna in order to respect the regulated SAR limitation.

Design of a ring resonator-based optical beam forming network for phased array receive antennas

NARCIS (Netherlands)

van 't Klooster, J.W.J.R.; Roeloffzen, C.G.H.; Meijerink, Arjan; Zhuang, L.; Marpaung, D.A.I.; van Etten, Wim; Heideman, Rene; Leinse, Arne; Schippers, H.; Verpoorte, J.; Wintels, M.

2008-01-01

A novel squint-free ring resonator-based optical beam forming network (OBFN) for phased array antennas (PAA) is proposed. It is intended to provide broadband connectivity to airborne platforms via geostationary satellites. In this paper, we present the design of the OBFN and its control system. Our

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.

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.

Heating profiles on ICRF antenna Faraday shields

International Nuclear Information System (INIS)

Taylor, D.J.; Baity, F.W.; Hahs, C.L. Riemer, B.W.; Ryan, D.M.; Williamson, D.E.

1992-01-01

Poor definition of the heating profiles that occur during normal operation of Faraday shields for ion cyclotron resonant frequency (ICRF) antennas has complicated the mechanical design of ICRF system components. This paper reports that at Oak Ridge National Laboratory (ORNL), Faraday shield analysis is being used in defining rf heating profiles. In recent numerical analyses of proposed hardware for the Burning Plasma Experiment (BPX) and DIII-D, rf magnetic fields at Faraday shield surfaces were calculated, providing realistic predictions of the induced skin currents flowing on the shield elements and the resulting dissipated power profile. Detailed measurements on mock-ups of the Faraday shields for DIII-D and the Tokamak Fusion Test Reactor (TFTR) confirmed the predicted magnetic field distributions. A conceptual design for an uncooled Faraday shield for the BPX ion cyclotron resonance heating (ICRH) antenna, which should withstand the proposed long-pulse operation, has been completed. The analytical effort is described in detail, with emphasis on the design work for the BPX ICRH antenna conceptual design and for the replacement Faraday shield for the DIII-D FWCD antenna. Results of analyses are shown, and configuration issues involved in component modeling are discussed

Advanced Communication Technology Satellite (ACTS) multibeam antenna analysis and experiment

Science.gov (United States)

Acosta, Roberto J.; Lagin, Alan R.; Larko, Jeffrey M.; Narvaez, Adabelle

1992-01-01

One of the most important aspects of a satellite communication system design is the accurate estimation of antenna performance degradation. Pointing error, end coverage gain, peak gain degradation, etc. are the main concerns. The thermal or dynamic distortions of a reflector antenna structural system can affect the far-field antenna power distribution in a least four ways. (1) The antenna gain is reduced; (2) the main lobe of the antenna can be mispointed thus shifting the destination of the delivered power away from the desired locations; (3) the main lobe of the antenna pattern can be broadened, thus spreading the RF power over a larger area than desired; and (4) the antenna pattern sidelobes can increase, thus increasing the chances of interference among adjacent beams of multiple beam antenna system or with antenna beams of other satellites. The in-house developed NASA Lewis Research Center thermal/structural/RF analysis program was designed to accurately simulate the ACTS in-orbit thermal environment and predict the RF antenna performance. The program combines well establish computer programs (TRASYS, SINDA and NASTAN) with a dual reflector-physical optics RF analysis program. The ACTS multibeam antenna configuration is analyzed and several thermal cases are presented and compared with measurements (pre-flight).

Low-Profile, Dual-Wavelength, Dual-Polarized Antenna

Science.gov (United States)

Carswell, James R.

2010-01-01

A single-aperture, low-profile antenna design has been developed that supports dual-polarization and simultaneous operation at two wavelengths. It realizes multiple beams in the elevation plane, and supports radiometric, radar, and conical scanning applications. This antenna consists of multiple azimuth sticks, with each stick being a multilayer, hybrid design. Each stick forms the h-plane pattern of the C and Ku-band vertically and horizontally polarized antenna beams. By combining several azimuth sticks together, the elevation beam is formed. With a separate transceiver for each stick, the transmit phase and amplitude of each stick can be controlled to synthesize a beam at a specific incidence angle and to realize a particular side-lobe pattern. By changing the transmit phase distribution through the transceivers, the transmit antenna beam can be steered to different incidence angles. By controlling the amplitude distribution, different side lobe patterns and efficiencies can be realized. The receive beams are formed using digital beam synthesis techniques, resulting in very little loss in the receive path, thus enabling a very-low loss receive antenna to support passive measurements.

Multilayer Strip Dipole Antenna Using Stacking Technique and Its Application for Curved Surface

Directory of Open Access Journals (Sweden)

Charinsak Saetiaw

2013-01-01

Full Text Available This paper presents the design of multilayer strip dipole antenna by stacking a flexible copper-clad laminate utilized for curved surface on the cylindrical objects. The designed antenna will reduce the effects of curving based on relative lengths that are changed in each stacking flexible copper-clad laminate layer. Curving is different from each layer of the antenna, so the resonance frequency that resulted from an extended antenna provides better frequency response stability compared to modern antenna when it is curved or attached to cylindrical objects. The frequency of multilayer antenna is designed at 920 MHz for UHF RFID applications.

Antenna Design for Diversity and MIMO Application

DEFF Research Database (Denmark)

Ying, Zhinong; Chiu, Chi-Yuk; Zhao, Kun

2015-01-01

Recently, multiple-input multiple-output (MIMO) technology and diversity have attracted much attention both in industry and academia due to high data rate and high spectrum efficiency. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link, the diver...

Design and Analysis of Printed Yagi-Uda Antenna and Two-Element Array for WLAN Applications

Directory of Open Access Journals (Sweden)

Cai Run-Nan

2012-01-01

Full Text Available A printed director antenna with compact structure is proposed. The antenna is fed by a balanced microstrip-slotline and makes good use of space to reduce feeding network area and the size of antenna. According to the simulation results of CST MICROWAVE STUDIO software, broadband characteristics and directional radiation properties of the antenna are explained. The operating bandwidth is 1.8 GHz–3.5 GHz with reflection coefficient less than −10 dB. Antenna gain in band can achieve 4.5–6.8 dBi, and the overall size of antenna is smaller than 0.34λ0×0.58λ0. Then the antenna is developed to a two-element antenna array, working frequency and relative bandwidth of which are 2.15–2.87 GHz and 28.7%, respectively. Compared with antenna unit, the gain of the antenna array has increased by 2 dB. Thus the proposed antenna has characteristics of compact structure, relatively small size, and wideband, and it can be widely used in PCS/UMTS/WLAN/ WiMAX fields.

Composite GPS Patch Antenna for the AR Bandwidth Enhancement

Directory of Open Access Journals (Sweden)

Minkil Park

2016-01-01

Full Text Available A composite Global Positioning System (GPS patch antenna with a quadrature 3 dB hybrid coupler was designed and implemented for working RHCP and had a broadband axial ratio (AR bandwidth. We designed two patches as a FR-4 patch and 1.5 mm thickness thin ceramic patch with a quadrature 3 dB hybrid coupler. A CP radiation pattern was achieved, and the AR bandwidth improved by incorporating a quadrature 3 dB hybrid coupler feed structure in a micro-strip patch antenna. SMD by chip elements was applied to the quadrature 3 dB hybrid coupler. For the composite FR-4 and ceramic patch antennas, the VSWR measurement showed a 2 : 1 ratio over the entire design band, and the 3 dB AR bandwidth was 295 and 580 MHz for the FR-4 patch and ceramic patch antennas, respectively. The antenna gains for the composite FR-4 and ceramic patch antennas were measured as 1.36–2.75 and 1.47–2.71 dBi with 15.11–25.3% and 19.25–28.45% efficiency, respectively.

Liquid Crystal Bow-Tie Microstrip antenna for Wireless Communication Applications

Directory of Open Access Journals (Sweden)

B.T.P.Madhav

2014-06-01

Full Text Available In this paper we presented the design and analysis of Bow-Tie antenna on liquid crystal substrate, which is suitable for the Bluetooth/WLAN-2.4/WiBree/ZigBee applications. The Omni-directional radiation patterns along with moderate gain make the proposed antenna suitable for above mentioned applications. Details of the antenna design and simulated results Return loss, Input impedance, Radiation Patterns, E-Field, H-Field and Current Distributions, VSWR are presented and discussed. The proposed antenna is simulated at 2.4 GHz using Ansoft HFSS-11.

Present and future JET ICRF antennae

International Nuclear Information System (INIS)

Kaye, A.; Brown, T.; Bhatnagar, V.; Crawley, P.; Jacquinot, J.; Lobel, R.; Plancoulaine, J.; Rebut, P.H.; Wade, T.; Walker, C.

1994-01-01

Since the initial operation of the JET ICRF system in 1985, up to 22 MW has been coupled to the plasma, many heating scenarios have been demonstrated and the main technological problem of RF-specific impurity production overcome. Many developments of the antennae have taken place over this period, notably the replacement of the water-cooled nickel screens with indirectly cooled beryllium screens, and the forthcoming installation of eight new A2 antennae for operation during the pumped divertor phase of JET. The A2 antennae include enhanced provision for fast wave current drive experiments on JET. This paper describes the beryllium screens, the technological results from operation and subsequent inspection of these screens, the design of the A2 antennae and the results from high power RF testing of a model of the A2 antenna. (orig.)

How nature designs light-harvesting antenna systems: design principles and functional realization in chlorophototrophic prokaryotes

Science.gov (United States)

Bryant, Donald A.; Canniffe, Daniel P.

2018-02-01

Chlorophyll-based phototrophs, or chlorophototrophs, convert light energy into stored chemical potential energy using two types of photochemical reaction center (RC), denoted type-1 and type-2. After excitation with light, a so-called special pair of chlorophylls in the RC is oxidized, and an acceptor is reduced. To ensure that RCs function at maximal rates in diffuse and variable light conditions, chlorophototrophs have independently evolved diverse light-harvesting antenna systems to rapidly and efficiently transfer that energy to the RCs. Energy transfer between weakly coupled chromophores is generally believed to proceed by resonance energy transfer, a dipole-induced-dipole process that was initially described theoretically by Förster. Nature principally optimizes three parameters in antenna systems: the distance separating the donor and acceptor chromophores, the relative orientations of those chromophores, and the spectral overlap between the donor and the acceptor chromophores. However, there are other important biological parameters that nature has optimized, and some common themes emerge from comparisons of different antenna systems. This tutorial considers structural and functional characteristics of three fundamentally different light-harvesting antenna systems of chlorophotrophic bacteria: phycobilisomes of cyanobacteria, the light-harvesting complexes (LH1 and LH2) of purple bacteria, and chlorosomes of green bacteria. Phycobilisomes are generally considered to represent an antenna system in which the chromophores are weakly coupled, while the strongly coupled bacteriochlorophyll molecules in LH1 and LH2 are strongly coupled and are better described by exciton theory. Chlorosomes can contain up to 250 000 bacteriochlorophyll molecules, which are very strongly coupled and form supramolecular, nanotubular arrays. The general and specific principles that have been optimized by natural selection during the evolution of these diverse light

Gsm 1900Umts Printed Monopole Antenna For Mobile Base Station

Directory of Open Access Journals (Sweden)

Nyi Nyi Lwin

2015-08-01

Full Text Available In this paper printed rectangular monopole antenna which is basically printed microstrip patch antenna with partial ground plane is designed for mobile base station. The substrate FR4 with a relative permittivity of 4.4 and thickness 1.8 is used in design. In addition the printed monopole antenna is of low profile in appearance and suitable for most application. The proposed antenna can cover GSM1900 1850-1990 MHz and UMTS 1920-2170 MHz bands. Design and simulation processes are carried out with the aid of FEKO software which is used for the analysis of electromagnetic problems. Simulation results of the return loss gain and radiation patterns are presented.

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.

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.

Analysis and design of terahertz antennas based on plasmonic resonant graphene sheets

International Nuclear Information System (INIS)

Tamagnone, M.; Gómez-Díaz, J. S.; Perruisseau-Carrier, J.; Mosig, J. R.

2012-01-01

Resonant graphene antennas used as true interfaces between terahertz (THz) space waves and a source/detector are presented. It is shown that in addition to the high miniaturization related to the plasmonic nature of the resonance, graphene-based THz antenna favorably compare with typical metal implementations in terms of return loss and radiation efficiency. Graphene antennas will contribute to the development of miniature, efficient, and potentially transparent all-graphene THz transceivers for emerging communication and sensing application.

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.

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).

Implanted Antennas in Medical Wireless Communications

CERN Document Server

Rahmat-Samii, Yahya; Balanis, Constantine

2006-01-01

Implanted Antennas in Medical Wireless Communications summarizes the results of recent research activities on the subject of implanted antennas for medical wireless communication systems. It is anticipated that in the near future sophisticated medical devices will be implanted inside the human body for medical telemetry and telemedicine. To establish effective and efficient wireless links with these devices, it is pivotal to give special attention to antenna designs that are low profile, small, safe, and cost effective. In this book, authors Yahya Rahmat-Samii and Jaehoon Kim demonstrate how a

Beam-Steerable Microstrip-Fed Bow-Tie Antenna Array for Fifth Generation Cellular Communications

DEFF Research Database (Denmark)

Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert Frølund

2016-01-01

The design and performance of mm-wave phased array antenna for 5G mobile broadband communication systems has been provided in this manuscript. The antenna is designed on a N9000 PTFE substrate with 0.787 mm thickness and 2.2 dielectric constant and 65×130 mm2 overall dimension. Eight elements...... of bow-tie antennas have been used at the top-edge region of mobile phone PCB. The antenna elements fed by microstrip lines are designed to operate at 17 GHz. The simulated results give good performances in terms of different antenna parameters. In addition, an investigation on the distance between...

A Directional Antenna in a Matching Liquid for Microwave Radar Imaging

Directory of Open Access Journals (Sweden)

Saeed I. Latif

2015-01-01

Full Text Available The detailed design equations and antenna parameters for a directional antenna for breast imaging are presented in this paper. The antenna was designed so that it could be immersed in canola oil to achieve efficient coupling of the electromagnetic energy to the breast tissue. Ridges were used in the horn antenna to increase the operating bandwidth. The antenna has an exponentially tapered section for impedance matching. The double-ridged horn antenna has a wideband performance from 1.5 GHz to 5 GHz (3.75 GHz or 110% of impedance bandwidth, which is suitable for breast microwave radar imaging. The fabricated antenna was tested and compared with simulated results, and similar bandwidths were obtained. Experiments were conducted on breast phantoms using these antennas, to detect a simulated breast lesion. The reconstructed image from the experiments shows distinguishable tumor responses indicating promising results for successful breast cancer detection.

Recent results of JT-60U ICRF antenna operation

International Nuclear Information System (INIS)

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

1994-01-01

Ion cyclotron range of frequencies (ICRF) heating is one of attractive plasma heating methods for reactor grade tokamaks, because it is quite effective in the wide ranges of plasma density and temperature. An antenna which should inject high power into plasma has been developed intensively because the heating efficiency and the coupling properties depend on its design. The antenna was operated at a small antenna-plasma gap in the JT-60 in out of phase mode, which showed the high heating efficiency to obtain high loading resistance, and similarly to other tokamaks. However, in order to reduce heat load to the antenna from plasma, a wide gap is required in reactor grade tokamaks such as ITER, in which the gap is designed to be 0.15 m in CDA. Two new antennas were fabricated for the JT-60U, which were designed to obtain high loading resistance at a wide gap for (π,0) phasing. The JT-60U ICRF heating system is explained. Also the JT-60U antenna is described. Antenna conditioning has been conducted well in the initial operation period. The phasing mode was set at (π,0) phasing, in which high heating efficiency is expected. The procedure is explained. The coupling and radiation loss properties during ICRF heating are reported. The JT-60U ICRF antennas were conditioned quickly with about 70 shots. The maximum coupled power was 6.4 MW for (π,0) phasing, and the power density was 6.1 MW/m 2 . (K.I.)