WorldWideScience

Sample records for antenna radiation patterns

  1. Radiation pattern from a cold magnetoplasma antenna

    International Nuclear Information System (INIS)

    In this paper a theoretical study of the radiation pattern of an antenna build up from a confined magnetoplasma is made. Assuming that the electron gas is in the linear regime, we derived expressions for the conductivity tensor of the plasma and the radiated electromagnetic field under the influence of both dc magnetic and ac electric externally applied fields. It is found that the radiation patterns are dependent on the relative orientations of the applied fields and in the frequency of the applied electric field.

  2. A FLOSS Tool for Antenna Radiation Patterns

    CERN Document Server

    Yannopoulou, Nikolitsa

    2010-01-01

    This paper briefly highlights the features of the software tool [RadPat4W], named after Radiation Patterns for Windows but also compatible with the [Wine] environment of Linux. The tool is a stand-alone part of a freeware suite that is based on an alternative exposition of fundamental Antenna Theory and is under active development for many years now. Nevertheless, [RadPat4W] source code has been now released as FLOSS Free Libre Open Source Software and thus it may be freely used, copied, modified or redistributed, individually or cooperatively, by the interested user to suit her/his personal needs for reliable antenna applications from the simplest to the more complex.

  3. Substrate Integrated Slot Array Antenna with Required Radiation Pattern Envelope

    Directory of Open Access Journals (Sweden)

    M. M. Zhou

    2016-01-01

    Full Text Available A substrate integrated slot array antenna with a prescribed radiation pattern is investigated in this paper. To meet the requirement of a certain standard radiation pattern envelope, the array configuration and the element excitation coefficient should be considered together. An efficient and systematic method is proposed to determine the element number and element weights in a planar array. After that, the geometrical dimension of the substrate integrated slot array can be synthesized. As an example, a K-band 16 × 22 slot array antenna based on the substrate integrated waveguide (SIW technology is designed, fabricated, and measured. Its radiation pattern can meet the class 3 antenna radiation pattern envelope of the European Telecommunications Standards Institute (ETSI standard pattern. Experimental results are in good agreement with simulated ones.

  4. Fano resonances in antennas: General control over radiation patterns

    CERN Document Server

    Rybin, Mikhail V; Filonov, Dmitry S; Slobozhanyuk, Alexey P; Belov, Pavel A; Kivshar, Yuri S; Limonov, Mikhail F

    2013-01-01

    The concepts of many optical devices are based on the fundamental physical phenomena such as resonances. One of the commonly used devices is an electromagnetic antenna that converts localized energy into freely propagating radiation and vise versa, offering unique capabilities for controlling electromagnetic radiation. Here we propose a concept for controlling the intensity and directionality of electromagnetic wave scattering in radio-frequency and optical antennas based on the physics of Fano resonances. We develop an analytical theory of spatial Fano resonances in antennas that describes switching of the radiation pattern between the forward and backward directions, and confirm our theory with both numerical calculations and microwave experiments. Our approach bridges the concepts of conventional radio antennas and photonic nanoantennas, and it provides a paradigm for the design of wireless optical devices with various functionalities and architectures.

  5. Capacitively Loaded Loop-Based Antennas with Reconfigurable Radiation Patterns

    Directory of Open Access Journals (Sweden)

    Saber Dakhli

    2015-01-01

    Full Text Available A class of metamaterial-inspired antennas having reconfigurable radiation patterns is proposed. They consist of a driven monopole antenna with one- and two-capacitively loaded loop (CLL, near field resonant parasitic elements. Two configurations are studied by considering the state of these CLL elements as being either open or closed configurations. Simulation results explain the design features and demonstrate that the structure can change its beam direction simply by controlling the switched states. Two prototypes with one- and two-CLL elements were fabricated and tested. The measured impedance mismatch and radiation pattern results are presented and compared to the corresponding simulated values.

  6. Hilbert-Curve Fractal Antenna With Radiation- Pattern Diversity

    Science.gov (United States)

    Nessel, James A.; Miranda, Felix A.; Zaman, Afroz

    2007-01-01

    A printed, folded, Hilbert-curve fractal microwave antenna has been designed and built to offer advantages of compactness and low mass, relative to other antennas designed for the same operating frequencies. The primary feature of the antenna is that it offers the advantage of radiation-pattern diversity without need for electrical or mechanical switching: it can radiate simultaneously in an end-fire pattern at a frequency of 2.3 GHz (which is in the S-band) and in a broadside pattern at a frequency of 16.8 GHz (which is in the Ku-band). This radiation-pattern diversity could be utilized, for example, in applications in which there were requirements for both S-band ground-to-ground communications and Ku-band ground-to-aircraft or ground-to-spacecraft communications. The lack of switching mechanisms or circuitry makes this antenna more reliable, easier, and less expensive to fabricate than it otherwise would be.

  7. Change of radiation pattern in a plasma monopole antenna

    Science.gov (United States)

    Siahpoush, V.; Shokri, B.

    2016-07-01

    In the present work, we have numerically solved the dispersion equation of the surface wave propagating on a uniform collisional plasma column. The electric field and surface current distributions have been computed in different situations. We have investigated the effect of plasma frequency variation on the spatial distribution of the surface current. Results show that varying the electron density of the plasma column enables the plasma column to work as a plasma monopole antenna with a fixed geometrical structure and excited frequency which is able to create different radiation patterns. Our numerical analysis also shows that a little change in the radius of the plasma column has a strong influence on the current distribution at the excited frequency in RF region. This effect can be ignored in the usual (metallic) antenna while it is very important in designing of the plasma monopole antenna.

  8. Radiation pattern of plasmonic nano-antennas in a homogeneous medium.

    Science.gov (United States)

    Sugita, Takafumi; Yanazawa, Kaori; Maeda, Satoshi; Hofmann, Holger F; Kadoya, Yutaka

    2014-06-01

    Radiation patterns from plasmonic nano-antennas formed on a glass substrate were investigated using index-matching oils. It was confirmed that the pattern from single nano-antennas for various cases of index-mismatching between the substrate and the oil is explained well by the patterns of infinitesimal electric dipoles. We found that for an angular resolution of 2°, the index mismatch must be smaller than 0.001 to realize isotropic radiation. By using the appropriate condition, the radiation patterns of nano Yagi-Uda antennas in a quasi-homogeneous medium were obtained experimentally.

  9. Near Field Radiation Patterns for an Ultra-Wide-Band Antenna

    OpenAIRE

    Blackledge, Jonathan; Babajanov, Bazar

    2013-01-01

    We present a three-dimensional time dependent model for simulating the electromagnetic radiation field patterns generated by Ultra-Wide- Band (UWB) antennas. UWB antennas are pulsed mode radiators used to communicate information at high bit rates over short distance. This affects the spatial characteristics of the field patterns assumed to be generated when a Continuous Wave (CW) model is used and this paper investigates the difference between the near field intensity patterns generated when ...

  10. Laboratory characterization of a GPR antenna for high-resolution testing: radiation pattern and vertical resolution

    OpenAIRE

    Pérez Gracia, María de la Vega; Capua, Daniel di; González Drigo, José Ramón; Pujades Beneit, Lluís

    2009-01-01

    High-resolution ground-penetrating radar (GPR) evaluations of structures are usually carried out using antennas with high nominal centre frequencies (between 1 and 2GHz). A comprehensive characterization of such an antenna would make it possible to determine the capabilities of a system and obtain accurate data interpretations. This paper describes the experimental determination of the radiation pattern of a commercial 1.6 GHz antenna, which forms part of a comprehensive experimental chara...

  11. Novel On-Wafer Radiation Pattern Measurement Technique for MEMS Actuator Based Reconfigurable Patch Antennas

    Science.gov (United States)

    Simons, Rainee N.

    2002-10-01

    The paper presents a novel on-wafer, antenna far field pattern measurement technique for microelectromechanical systems (MEMS) based reconfigurable patch antennas. The measurement technique significantly reduces the time and the cost associated with the characterization of printed antennas, fabricated on a semiconductor wafer or dielectric substrate. To measure the radiation patterns, the RF probe station is modified to accommodate an open-ended rectangular waveguide as the rotating linearly polarized sampling antenna. The open-ended waveguide is attached through a coaxial rotary joint to a Plexiglas(Trademark) arm and is driven along an arc by a stepper motor. Thus, the spinning open-ended waveguide can sample the relative field intensity of the patch as a function of the angle from bore sight. The experimental results include the measured linearly polarized and circularly polarized radiation patterns for MEMS-based frequency reconfigurable rectangular and polarization reconfigurable nearly square patch antennas, respectively.

  12. Reconfigurable antenna pattern verification

    Science.gov (United States)

    Drexler, Jerome P. (Inventor); Becker, Robert C. (Inventor); Meyers, David W. (Inventor); Muldoon, Kelly P. (Inventor)

    2013-01-01

    A method of verifying programmable antenna configurations is disclosed. The method comprises selecting a desired antenna configuration from a plurality of antenna configuration patterns, with the selected antenna configuration forming at least one reconfigurable antenna from reconfigurable antenna array elements. The method validates the formation of the selected antenna configuration to determine antenna performance of the at least one reconfigurable antenna.

  13. The radiation pattern of a monopole antenna attached to a conducting box

    Science.gov (United States)

    Chu, Andrew W. C.; Long, Stuart A.; Wilton, Donald R.

    1990-01-01

    A system investigation was undertaken to determine the radiation patterns of a monopole antenna mounted on a cubical conducting box over a ground plane. The effects of the location of the monopole and the electrical size of the box were compared with similar patterns measured over a flat ground plane and with numerically predicted values obtained from a method-of-moments patch code. It was concluded that the location at which a monopole antenna is mounted on a conducting box and the electrical size of the box clearly affect the overall radiation pattern of a monopole antenna. In general, mounting the antenna away from the center of the box will increase the depth of the nulls. In particular, planes will also increase the maximum E(phi) component of the field to the extent that it can become comparable to E(theta).

  14. Modified CPW Fed Monopole Antenna with Suitable Radiation Pattern for Mobile Handset

    Directory of Open Access Journals (Sweden)

    D. Laila

    2011-09-01

    Full Text Available A coplanar wave guide (CPW fed printed monopole antenna with reduced radiation hazard for mobile handset is presented. The antenna offers a bandwidth of 150MHz when printed on a substrate of dielectric constant (εr 4.4 and thickness 1.6mm with an overall dimension of 0.41λg X 0.31λg.The printed metal strip in the back side of the monopole modifies the radiation pattern suitable for mobile handset. Experimental and simulation studies of the proposed antenna are presented and discussed. A 20 dB reduction of radiated power in one quadrant of the radiation pattern offers a reduction of radiation towards the users head.

  15. Engineering antenna radiation patterns via quasi-conformal mappings.

    Science.gov (United States)

    García-Meca, Carlos; Martínez, Alejandro; Leonhardt, Ulf

    2011-11-21

    We use a combination of conformal and quasi-conformal mappings to engineer isotropic electromagnetic devices that modify the omnidirectional radiation pattern of a point source. For TE waves, the designed devices are also non-magnetic. The flexibility offered by the proposed method is much higher than that achieved with conformal mappings. As a result, it is shown that complex radiation patterns can be achieved, which can combine high directivity in a desired number of arbitrary directions and isotropic radiation in other specified angular ranges. In addition, this technique enables us to control the power radiated in each direction to a certain extent. The obtained results are valid for any part of the spectrum. The potential of this method is illustrated with some examples. Finally, we study the frequency dependence of the considered devices and propose a practical dielectric implementation.

  16. Dual Strip-Excited Dielectric Resonator Antenna with Parasitic Strips for Radiation Pattern Reconfigurability

    Directory of Open Access Journals (Sweden)

    M. Kamran Saleem

    2014-01-01

    Full Text Available A novel pattern reconfigurable antenna concept utilizing rectangular dielectric resonator antenna (DRA placed over dielectric substrate backed by a ground plane is presented. A dual strip excitation scheme is utilized and both excitation strips are connected together by means of a 50 Ω microstrip feed network placed over the substrate. The four vertical metallic parasitic strips are placed at corner of DRA each having a corresponding ground pad to provide a short/open circuit between the parasitic strip and antenna ground plane, through which a shift of 90° in antenna radiation pattern in elevation plane is achieved. A fractional bandwidth of approximately 40% at center frequency of 1.6 GHz is achieved. The DRA peak realized gain in whole frequency band of operation is found to be above 4 dB. The antenna configuration along with simulation and measured results are presented.

  17. EM Modeling of Far-Field Radiation Patterns for Antennas on the GMA-TT UAV

    Science.gov (United States)

    Mackenzie, Anne I.

    2015-01-01

    To optimize communication with the Generic Modular Aircraft T-Tail (GMA-TT) unmanned aerial vehicle (UAV), electromagnetic (EM) simulations have been performed to predict the performance of two antenna types on the aircraft. Simulated far-field radiation patterns tell the amount of power radiated by the antennas and the aircraft together, taking into account blockage by the aircraft as well as radiation by conducting and dielectric portions of the aircraft. With a knowledge of the polarization and distance of the two communicating antennas, e.g. one on the UAV and one on the ground, and the transmitted signal strength, a calculation may be performed to find the strength of the signal travelling from one antenna to the other and to check that the transmitted signal meets the receiver system requirements for the designated range. In order to do this, the antenna frequency and polarization must be known for each antenna, in addition to its design and location. The permittivity, permeability, and geometry of the UAV components must also be known. The full-wave method of moments solution produces the appropriate dBi radiation pattern in which the received signal strength is calculated relative to that of an isotropic radiator.

  18. The vertical pattern of microwave radiation around BTS (Base Transceiver Station) antennae in Hashtgerd township

    OpenAIRE

    Nasseri, Simin; Monazzam, Mohammadreza; Beheshti, Meisam; Zare, Sajad; Mahvi, Amirhosein

    2013-01-01

    New environmental pollutants interfere with the environment and human life along with technology development. One of these pollutants is electromagnetic field. This study determines the vertical microwave radiation pattern of different types of Base Transceiver Station (BTS) antennae in the Hashtgerd city as the capital of Savojbolagh County, Alborz Province of Iran. The basic data including the geographical location of the BTS antennae in the city, brand, operator type, installation and its ...

  19. Surface accuracy and radiation pattern characteristics of mesh deployable refector antennas

    Science.gov (United States)

    Ueno, Miyoshi; Ebisui, Takashi; Okamato, Teruki; Orikasa, Teruaki; Sugimoto, Toshio; Iso, Akio

    To facilitate the growth of mobile satellite communications, both an increase in the Equivalent Isotropically Radiated Power (EIRP) of satellites and improved frequency reuse are required to achiveve compact size, low cost terminal usage, and high channel capacity. High gain and low sidelobe antenna technology are very important for high EIRP and frequency reuse, respectively. These requirements are expected to be met by using a large deployable mesh reflector antenna, which is the key technology for future multibeam moble communications systems. In this paper, surface accruracy and related electrical characteristics are studied using a TETRUS-(Tetra Trigonal Prism Truss) type deployable mesh reflector antenna. Surface accuracy and related electrical characteristics of reflector antennas becaue any distortion of the ideal paraboloidal configuration causes antenna patterns to deteriorate, thereby reducing reflector aperture efficiency and increasing sidelobe and grating lobe levels. The sidelobe and grating lobe characteristics are especially important in frequency reuse. First, we show the problem with the radiation pattern characteristics of TETUS antenna. We then propose a new antenna configuration called the 'HYBRID TETRUS' that improves these characteristics. The mechanical performances of two partial deployable models are also described. Mechanical testing results reveal agreement between the calculated and measured values and high rigidities.

  20. Study of high speed complex number algorithms. [for determining antenna for field radiation patterns

    Science.gov (United States)

    Heisler, R.

    1981-01-01

    A method of evaluating the radiation integral on the curved surface of a reflecting antenna is presented. A three dimensional Fourier transform approach is used to generate a two dimensional radiation cross-section along a planer cut at any angle phi through the far field pattern. Salient to the method is an algorithm for evaluating a subset of the total three dimensional discrete Fourier transform results. The subset elements are selectively evaluated to yield data along a geometric plane of constant. The algorithm is extremely efficient so that computation of the induced surface currents via the physical optics approximation dominates the computer time required to compute a radiation pattern. Application to paraboloid reflectors with off-focus feeds in presented, but the method is easily extended to offset antenna systems and reflectors of arbitrary shapes. Numerical results were computed for both gain and phase and are compared with other published work.

  1. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Science.gov (United States)

    Teperik, Tatiana V.; de Lustrac, André

    2015-12-01

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  2. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Energy Technology Data Exchange (ETDEWEB)

    Teperik, Tatiana V., E-mail: tatiana.teperik@u-psud.fr [Univ. Paris-Sud, Institut d’Electronique Fondamentale, UMR 8622, Orsay F-91405 (France); Donostia International Physics Center, Aptdo. 1072, 20080 San Sebastian (Spain); Lustrac, André de [Univ. Paris-Sud, Institut d’Electronique Fondamentale, UMR 8622, Orsay F-91405 (France); Univ. Paris-Ouest, 92410 Ville d’Avray (France)

    2015-12-15

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  3. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    International Nuclear Information System (INIS)

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%

  4. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Directory of Open Access Journals (Sweden)

    Tatiana V. Teperik

    2015-12-01

    Full Text Available We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  5. 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.

  6. 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.

  7. Stepped Cylindrical Antenna with a Higher-Order Mode Ring Patch for Wideband Conical Radiation Pattern

    Directory of Open Access Journals (Sweden)

    Jinpil Tak

    2015-01-01

    Full Text Available A stepped cylindrical antenna with a higher-order mode ring patch for wideband conical radiation pattern is proposed. To accomplish a low profile with wideband conical radiation characteristics, a stepped cylindrical monopole and a TM41 higher-order mode ring patch with four shorting pins are utilized. The proposed antenna has a monopole-like radiation pattern with a wide 10-dB return loss bandwidth of 11 GHz (2 GHz–13 GHz. It can cover various wireless services, such as wireless broadband (WiBro; 2.3 GHz–2.39 GHz, wireless local area networks (WLAN; 2.4 GHz–2.484 GHz, 5.15 GHz–5.35 GHz, and 5.725 GHz–5.875 GHz, digital multimedia broadcasting (DMB; 2.63 GHz–2.655 GHz, and ultra wideband (UWB; 3.1 GHz–10.6 GHz. The antenna has a height of only 0.12λ0 at 2 GHz.

  8. The vertical pattern of microwave radiation around BTS (Base Transceiver Station) antennae in Hashtgerd township.

    Science.gov (United States)

    Nasseri, Simin; Monazzam, Mohammadreza; Beheshti, Meisam; Zare, Sajad; Mahvi, Amirhosein

    2013-01-01

    New environmental pollutants interfere with the environment and human life along with technology development. One of these pollutants is electromagnetic field. This study determines the vertical microwave radiation pattern of different types of Base Transceiver Station (BTS) antennae in the Hashtgerd city as the capital of Savojbolagh County, Alborz Province of Iran. The basic data including the geographical location of the BTS antennae in the city, brand, operator type, installation and its height was collected from radio communication office, and then the measurements were carried out according to IEEE STD 95. 1 by the SPECTRAN 4060. The statistical analyses were carried out by SPSS16 using Kolmogorov Smirnov test and multiple regression method. Results indicated that in both operators of Irancell and Hamrah-e-Aval (First Operator), the power density rose with an increase in measurement height or decrease in the vertical distance of broadcaster antenna. With mix model test, a significant statistical relationship was observed between measurement height and the average power density in both types of the operators. With increasing measuring height, power density increased in both operators. The study showed installing antennae in a crowded area needs more care because of higher radiation emission. More rigid surfaces and mobile users are two important factors in crowded area that can increase wave density and hence raise public microwave exposure. PMID:24359870

  9. Effect of the tank main gun on the radiation pattern of the monopole antenna

    Directory of Open Access Journals (Sweden)

    Miroslav Lj. Đorđević

    2011-01-01

    Full Text Available For telecommunication purposes, a monopole antenna is usually positioned on the tank turret. At low frequencies the whole tank has to be treated as a part of the antenna system. In this paper a method for electromagnetic modeling of metallic structures is presented and applied to the analysis of radiation of a tank monopole antenna. Radiation simulations are performed at the frequency range from 1MHz to 30MHz. A special attention is given to the analysis of the effects of increased elevation of the tank main gun to the radiation pattern of the antenna. The analysis of the radiation of the tank monopole is performed with and without the presence of conducting ground. It is shown that the increase in the main gun elevation at certain frequencies can lead to degradation of uniformity of radiation in the horizontal plane. Introduction Informational technologies and reliable and secure communications are an important part of a modern military doctrine. Regarding telecommunications, armored vehicles and tanks in particular present a specific problem. In this paper, a theoretical basis of the electromagnetic analysis of metallic structures and a modeling technique will be presented. The effect of the tank on the radiation pattern will be investigated both for a tank in free space and above the conducting ground. Method of moments The method of moments (MoM is a method for an approximate solution of integral equations. This section presents the fundamentals of the MoM and the higher-order quadrilaterals as the basic elements used for geometry modeling. The currents in our method are approximated using high-order two-dimensional polynomials. Modeling of the tank geometry The tank is modeled using only 28 elements, out of which 10 bilinear quadrilaterals and 18 second-order surfaces. The monopole antenna is modeled using one straight wire segment. Results The use of the polynomial current approximation yields a reduction in the number of unknowns required

  10. A Compact Single-Feed Circularly Polarized Microstrip Antenna with Symmetric and Wide-Beamwidth Radiation Pattern

    OpenAIRE

    Xihong Ye; Mang He; Pingyuan Zhou; Houjun Sun

    2013-01-01

    A compact single-feed circularly polarized microstrip antenna is proposed to achieve symmetric radiation pattern over a wide range of observation angles. In order to reduce the radiation aperture and consequently broaden the circular polarization (CP) and the half power beamwidth (HPBW) of the antenna, a partially etched superstrate and a conducting cavity are employed in the design. Further, reasonable axial ratio (AR) and impedance bandwidths are realized within the compact structure by usi...

  11. Antenna Radiation Pattern Influence on the Localization Accuracy in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    COCA, E.

    2013-05-01

    Full Text Available Localization or position determination is one of the most common applications for the wireless sensor networks. Many investigations have been made during the last decade, most of the effort being concentrated in the direction of improving the accuracy of the positioning results by using complex filtering and correction algorithms, and other techniques such as radio maps or directive antennas for the reference nodes. The most common sources of errors include reflections on nearby objects, radio frequency noise, and variable characteristics of the communication channel. In the vast majority of cases, several assumptions have been made in order to simplify the computing algorithms or the complexity of nodes, and finally their cost. The omnidirectional radiation pattern of the node antennas is such an assumption. In this paper we investigate theoretically and validate by measurements the influence of the radiation pattern on the localization accuracy of a wireless sensor node network. By taking into consideration the orientation of nodes, which could be provided by a local digital compass on each node, we demonstrate that the position accuracy could be improved with a minimum of resources. All measurements were made in radio emissions controlled environment - a semi-anechoic chamber, without affecting the generality of the proposed solution.

  12. Algorithm for the synthesis of linear antenna arrays with desired radiation pattern and integral amplitude coefficients

    Directory of Open Access Journals (Sweden)

    Sadchenko A. V.

    2015-06-01

    Full Text Available Ahe problem of technical implementation of phased array antennas (PAR with the required radiation pattern (RP is the complexity of the construction of the beamforming device that consists of a set of controlled attenuators and phase shifters. It is possible to simplify the technical implementation of PAR, if complex representation of coefficients of amplitude-phase distribution of the field along the lattice is approximated by real values in the synthesis stage. It is known that the amplitude distribution of the field in the aperture of the antenna array and the radiation pattern are associated with Fourier transform. Thus, the amplitude and phase coefficients are first calculated using the Fourier transform, and then processed according to the selected type of circuit realization of attenuators and phase shifters. The calculation of the inverse Fourier transform of the modified coefficients allows calculating the synthesized orientation function. This study aims to develop a search algorithm for amplitude and phase coefficients, taking into account the fact that integer-valued amplitudes and phases are technically easier to implement than real ones. Synthesis algorithm for equidistant linear array with a half-wavelength irradiators pitch (&l;/2 is as follows. From a given directivity function the discrete Fourier transform (DFT in the form of an array of complex numbers is found, the resulting array is then transformed into a set of attenuations for attenuators and phase shifts for phase shifters, while the amplitude coefficients are rounded off to integers, and phases are binarizated (0, ?. The practical value of this algorithm is particularly high when using controlled phase shifters and attenuators integrally. The work confirms the possibility of a thermoelectric converter of human body application for an electronic medical thermometer power supply.

  13. Radiation Pattern Measurement of a Low-Profile Wearable Antenna Using an Optical Fibre and a Solid Anthropomorphic Phantom

    Directory of Open Access Journals (Sweden)

    Tian Hong Loh

    2014-08-01

    Full Text Available This paper presents a study into radiation pattern measurements of an electrically small dielectric resonator antenna (DRA operating between 2.4 and 2.5 GHz in the industrial, scientific and medical (ISM radio band for body-centric wireless communication applications. To eliminate the distortion of the radiation pattern associated with the unwanted radiation from a metallic coaxial cable feeding the antenna we have replaced it with a fibre optic feed and an electro-optical (EO transducer. The optical signal is then converted back to RF using an Opto-Electric Field Sensor (OEFS system. To ensure traceable measurements of the radiation pattern performance of the wearable antenna a generic head and torso solid anthropomorphic phantom model has been employed. Furthermore, to illustrate the benefits of the method, numerical simulations of the co-polar and cross-polar H-plane radiation patterns at 2.4, 2.45, and 2.5 GHz are compared with the measured results obtained using: (i an optical fibre; and (ii a metallic coaxial cable.

  14. Knowledge-based antenna pattern extrapolation

    OpenAIRE

    Robinson, Michael

    2012-01-01

    We describe a theoretically-motivated algorithm for extrapolation of antenna radiation patterns from a small number of measurements. This algorithm exploits constraints on the antenna's underlying design to avoid ambiguities, but is sufficiently general to address many different antenna types. A theoretical basis for the robustness of this algorithm is developed, and its performance is verified in simulation using a number of popular antenna designs.

  15. Antenna with Dielectric Having Geometric Patterns

    Science.gov (United States)

    Dudley, Kenneth L. (Inventor); Elliott, Holly A. (Inventor); Cravey, Robin L. (Inventor); Connell, John W. (Inventor); Ghose, Sayata (Inventor); Watson, Kent A. (Inventor); Smith, Jr., Joseph G. (Inventor)

    2013-01-01

    An antenna includes a ground plane, a dielectric disposed on the ground plane, and an electrically-conductive radiator disposed on the dielectric. The dielectric includes at least one layer of a first dielectric material and a second dielectric material that collectively define a dielectric geometric pattern, which may comprise a fractal geometry. The radiator defines a radiator geometric pattern, and the dielectric geometric pattern is geometrically identical, or substantially geometrically identical, to the radiator geometric pattern.

  16. Directional Pattern Analysis of a Linear Phased Antenna

    Directory of Open Access Journals (Sweden)

    Jan Haring

    2008-01-01

    Full Text Available An antenna array is a system compound from simply radiators (dipoles, microstrip antennas, that together form desired radiation pattern. Phased array antennas consist of multiple stationary antenna elements, that are fed coherently and use variable phase or time-delay control at each element to scan a beam to given angles in space. Variable amplitude control is sometimes also provided for antenna pattern shaping.

  17. A Compact Single-Feed Circularly Polarized Microstrip Antenna with Symmetric and Wide-Beamwidth Radiation Pattern

    Directory of Open Access Journals (Sweden)

    Xihong Ye

    2013-01-01

    Full Text Available A compact single-feed circularly polarized microstrip antenna is proposed to achieve symmetric radiation pattern over a wide range of observation angles. In order to reduce the radiation aperture and consequently broaden the circular polarization (CP and the half power beamwidth (HPBW of the antenna, a partially etched superstrate and a conducting cavity are employed in the design. Further, reasonable axial ratio (AR and impedance bandwidths are realized within the compact structure by using a simple series crossed-slot aperture coupled feeding. As a consequence, the overall dimension of the fabricated prototype is 0.32λ0 × 0.32λ0 × 0.12λ0 at the center operating frequency of 1.56 GHz, and a 3.0% overlapped bandwidth of 10 dB return loss (RL and 3 dB AR is obtained. Within the bandwidth, symmetric CP radiation pattern over almost the entire upper hemisphere is observed and the HPBW is also increased from 60° to 106°.

  18. L-band compact printed quadrifilar helix antenna with ‘Iso-Flux' radiating pattern for stratospheric balloons telemetry

    OpenAIRE

    Fonseca, Nelson; Hebib, Sami; Aubert, Hervé

    2008-01-01

    International audience Two sinusoidal profile compact printed quadrifilar helix antennas have been presented. Particular care has been given to the co and cross-polarization patterns during the parametric design process to produce antennas with performances very similar to the conventional one in those aspects. A size reduction ranging from 30 to 40% is confirmed. Experimental validation will be presented at the conference.

  19. Using Distributed Targets To Determine SAR Antenna Patterns

    Science.gov (United States)

    Freeman, Anthony

    1994-01-01

    Improved method of determining radiation pattern of synthetic-aperture radar (SAR) antenna with respect to elevation-angle coordinate (angle of roll about flight path) devised. Essence of method is solving radar equation in such way as to enable extraction of antenna pattern from SAR images of uniform distributed targets. Needed because radiation pattern in flight can differ from that observed in laboratory test of antenna. Computations include subtraction of noise, test for uniformity, and least-squares estimate.

  20. Radiation Patterns of Big Antennas Based on Optics Measurement%基于光学测量的大型天线测试方法研究

    Institute of Scientific and Technical Information of China (English)

    王宏建; 郝齐焱; 易敏; 陈雪; 刘广; 刘世华; 赵鑫

    2013-01-01

    提出了一种基于光学照相的电磁场数值计算测试电大尺寸天线辐射特性的新方法.根据光学照相实测大型天线的形面三维坐标计算出天线表面电流分布,利用物理光学计算得到天线远场方向图和增益.采用该方法得到的海洋二号校正辐射计观测天线和充气天线的辐射特性与平面近场测试结果的对比验证了其具有足够的准确性.该方法具有快速、灵活的特点,可以推广到电大尺寸天线测试.%A new method to measure the large-aperture antenna radiation patterns was proposed. It is difficult for far-field, near-field and CATR measurement to meet the measurement requirements of electrically large antenna. Surface measurement of parabolic reflector antenna by photogrammetry at multiple points can achieve high accuracy, even electronic theodolite and laser interferometer can achieve more accuracy to meet surface measurement requirement of large-aperture terahertz antenna. This method used the data obtained by actual optical measurement to simulate the real antenna radiation by physical optics method. Because of using the real antenna measured data, this simulation method gave the actual antenna gain and radiation results. The simulation results agreed well with the antennas patterns obtained by the real near-field tests. This method was fast and much adaptable for the large-aperture antenna.

  1. System integration and radiation pattern measurements of a phased array antenna employing an integrated photonic beamformer for radio astronomy applications.

    Science.gov (United States)

    Burla, Maurizio; Roeloffzen, Chris G H; Zhuang, Leimeng; Marpaung, David; Khan, Muhammad Rezaul; Maat, Peter; Dijkstra, Klaas; Leinse, Arne; Hoekman, Marcel; Heideman, René

    2012-03-01

    In this paper we describe the system integration and the experimental demonstration of a photonically beamformed four-element receiving array antenna for radio astronomy applications. To our knowledge, the work described here is the first demonstration of the squint-free, continuously tunable beamsteering capability offered by an integrated photonic beamformer based on optical ring resonator true-time-delay units, with measured radiation patterns. The integrated beamformer is realized in a low loss, complementary metal-oxide-semiconductor (CMOS) compatible optical waveguide technology. The measurements show a wideband, continuous beamsteering operation over a steering angle of 23.5 degrees and an instantaneous bandwidth of 500 MHz limited only by the measurement setup. PMID:22410879

  2. Multi-Variable Model-Based Parameter Estimation Model for Antenna Radiation Pattern Prediction

    Science.gov (United States)

    Deshpande, Manohar D.; Cravey, Robin L.

    2002-01-01

    A new procedure is presented to develop multi-variable model-based parameter estimation (MBPE) model to predict far field intensity of antenna. By performing MBPE model development procedure on a single variable at a time, the present method requires solution of smaller size matrices. The utility of the present method is demonstrated by determining far field intensity due to a dipole antenna over a frequency range of 100-1000 MHz and elevation angle range of 0-90 degrees.

  3. Characteristics of the GPR field pattern antennas

    Science.gov (United States)

    Pérez-Gracia, V.; González-Drigo, R.; Di Capua, D.; Pujades, L. G.

    2007-10-01

    Ground-Penetrating Radar has become a popular non-destructive and non-invasive tool in different kind of applications: civil engineering, archaeology, concrete and masonry analysis, etc. The selection of the antenna frequencies depends on the application, but each antenna has a radiation pattern and some characteristics that have influence in the final interpretation and in the model obtained for the studied medium. The knowledge of these features and its coupling effects with the medium could improve the results of the GPR prospecting studies. In this work, some experimental procedures were carried out in order to obtain the 1.6 GHz centre frequency antenna characteristics in the air and in one material medium and to compare them. First, the study of the attenuation due to geometrical spreading was performed. This result was compared with the amplitude attenuation in a material medium, deduced from the GPR experimental data. Second, the shape of the radiation pattern was estimated in laboratory for different distances between the target and the antenna. Near field and far field were considered during the experimental data acquisition. Third, the relative amplitude of the reflected wave (in dB) was obtained depending on the relative position of the antenna over the target. The shape of the radiation pattern and the relative amplitudes obtained in the air were compared with those obtained in a slow medium (water). This slow medium was characterized with the wave velocity and the attenuation factor of the GPR signal.

  4. Synthesis of multiple shaped beam antenna patterns

    Science.gov (United States)

    Stutzman, W. L.; Coffey, E. L.

    1973-01-01

    Results are presented of research into the problem of finding an excitation of a given antenna such that the desired radiation pattern is approximated to within acceptable limits. This is to be done in such a fashion that boundary conditions involving hardware limitations may be inserted into the problem. The intended application is synthesis of multiple shaped beam antennas. Since this is perhaps the most difficult synthesis problem an antenna engineer is likely to encounter, the approach taken was to include as a by-product capability for synthesizing simpler patterns. The synthesis technique has been almost totally computerized. The class of antennas which may be synthesized with the computer program are those which may be represented as planar (continuous or discrete) current distributions. The technique is not limited in this sense and could indeed by extended to include, for example, the synthesis of conformal arrays or current distributions on the surface of reflectors. The antenna types which the program is set up to synthesize are: line source, rectangular aperture, circular aperture, linear array, rectangular array, and arbitrary planar array.

  5. Size reduction and radiation pattern shaping of multi-fed DCC slot antennas used in conformal microwave array hyperthermia applicators.

    Science.gov (United States)

    Maccarini, Paolo F; Arunachalam, Kavitha; Martins, Carlos D; Stauffer, Paul R

    2009-02-23

    The use of conformal antenna array in the treatment of superficial diseases can significantly increase patient comfort while enhancing the local control of large treatment area with irregular shapes. Originally a regular square multi-fed slot antenna (Dual Concentric Conductor - DCC) was proposed as basic unit cell of the array. The square DCC works well when the outline of the treatment area is rectangular such as in the main chest or back area but is not suitable to outline diseases spreading along the armpit and neck area. In addition as the area of the patch increases, the overall power density decreases affecting the efficiency and thus the ability to deliver the necessary thermal dose with medium power amplifier (antennas is preferable as the disease is more accurately contoured and the lower power requirement for the amplifiers correlates with system reliability, durability, linearity and overall reduced cost. For such reason we developed a set of design rules for multi-fed slot antennas with irregular contours and we implemented a design that reduce the area while increasing the perimeter of the slot, thus increasing the antenna efficiency and the power density. The simulation performed with several commercial packages (Ansoft HFSS, Imst Empire, SemcadX and CST Microwave Studio) show that the size reducing method can be applied to several shapes and for different frequencies. The SAR measurements of several DCCs are performed using an in-house high resolution scanning system with tumor equivalent liquid phantom both at 915 MHz for superficial hyperthermia systems in US) and 433 MHz (Europe). The experimental results are compared with the expected theoretical predictions and both simulated and measured patterns of single antennas of various size and shapes are then summed in various combinations using Matlab to show possible treatment irregular contours of complex diseases. The local control is expected to significantly improve while maintaining the patient

  6. Size reduction and radiation pattern shaping of multi-fed DCC slot antennas used in conformal microwave array hyperthermia applicators.

    Science.gov (United States)

    Maccarini, Paolo F; Arunachalam, Kavitha; Martins, Carlos D; Stauffer, Paul R

    2009-02-23

    The use of conformal antenna array in the treatment of superficial diseases can significantly increase patient comfort while enhancing the local control of large treatment area with irregular shapes. Originally a regular square multi-fed slot antenna (Dual Concentric Conductor - DCC) was proposed as basic unit cell of the array. The square DCC works well when the outline of the treatment area is rectangular such as in the main chest or back area but is not suitable to outline diseases spreading along the armpit and neck area. In addition as the area of the patch increases, the overall power density decreases affecting the efficiency and thus the ability to deliver the necessary thermal dose with medium power amplifier (antennas is preferable as the disease is more accurately contoured and the lower power requirement for the amplifiers correlates with system reliability, durability, linearity and overall reduced cost. For such reason we developed a set of design rules for multi-fed slot antennas with irregular contours and we implemented a design that reduce the area while increasing the perimeter of the slot, thus increasing the antenna efficiency and the power density. The simulation performed with several commercial packages (Ansoft HFSS, Imst Empire, SemcadX and CST Microwave Studio) show that the size reducing method can be applied to several shapes and for different frequencies. The SAR measurements of several DCCs are performed using an in-house high resolution scanning system with tumor equivalent liquid phantom both at 915 MHz for superficial hyperthermia systems in US) and 433 MHz (Europe). The experimental results are compared with the expected theoretical predictions and both simulated and measured patterns of single antennas of various size and shapes are then summed in various combinations using Matlab to show possible treatment irregular contours of complex diseases. The local control is expected to significantly improve while maintaining the patient

  7. 频率与方向图可重构微带天线设计%Design of frequency and radiation pattern reconfigurable microstrip antenna

    Institute of Scientific and Technical Information of China (English)

    赵轶卓; 陈春红; 马伟男; 邾志民

    2015-01-01

    This paper presents a microstrip patch antenna with reconfigurable frequency and pattern to meet the needs of wireless communication system miniaturization and antenna multifunction. The configuration consists of a radiation patch with an U-shaped slot and two symmetrical parasitic patches. The reconfigurations of frequency and pattern can be achieved by changing the operating states of the PIN diode on the U-shaped slot and parasitic patches. Simulation and test results show that the antenna resonates at 5. 2 GHz or 5. 8 GHz, at the same time, the beam deflection and broadening can be achieved at both of the resonant frequencies. The reconfigurable frequencies and radiation patterns can be achieved by adopting the structure of a microstrip antenna, and the characteristic of multifunction is realized.%为了满足无线通信系统小型化和天线多功能的需求,设计了一种频率和方向图可重构的微带贴片天线. 该天线由一个带U型槽的辐射贴片和左右对称的寄生贴片构成,通过改变辐射贴片上U型槽和寄生贴片上PIN(正-本-负)二极管的工作状态来实现天线的工作频率和方向图的改变. 仿真和测试结果表明:天线的谐振频率可以在5 . 2 GHz和5 . 8 GHz之间切换,同时在两个频点都可以实现波束的左右偏转和展宽. 采用这种结构的微带天线可以同时实现频率和方向图的重构,从而实现天线的多功能.

  8. Analysis of destabilizing factors effect on hybrid reflector antenna radiation

    OpenAIRE

    Smorodin, G. N.; Braude, V. B.

    1995-01-01

    The paper deals with the effect of various destabilizing factors including manufacture inaccuracy on a hybrid reflector antenna (HRA) radiation pattern. Antenna designed for the airport precision approach radar (PAR) is considered as an example of HRA. Antenna uses a reflector 2.8*3.3 m cut of hyperboloid and an offset cylindrical phased array containing about seven hundred transmission-type waveguide phase shifters. The array is fed by a monopulse four-waveguide horn and is operated by a ste...

  9. Certified dual-corrected radiation patterns of phased antenna arrays by offline–online order reduction of finite-element models

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, A., E-mail: a.sommer@lte.uni-saarland.de; Farle, O., E-mail: o.farle@lte.uni-saarland.de; Dyczij-Edlinger, R., E-mail: edlinger@lte.uni-saarland.de

    2015-10-15

    This paper presents a fast numerical method for computing certified far-field patterns of phased antenna arrays over broad frequency bands as well as wide ranges of steering and look angles. The proposed scheme combines finite-element analysis, dual-corrected model-order reduction, and empirical interpolation. To assure the reliability of the results, improved a posteriori error bounds for the radiated power and directive gain are derived. Both the reduced-order model and the error-bounds algorithm feature offline–online decomposition. A real-world example is provided to demonstrate the efficiency and accuracy of the suggested approach.

  10. Radiation Characteristics of Rectangular Patch Antennas with an Array of Pins

    Institute of Scientific and Technical Information of China (English)

    Myung-ki CHO; Tae-young KIM; Boo-gyoun KIM

    2010-01-01

    The patch antennas with an array of pins (pin array patch antennas) with excellent radiation characteristics are investigated for various substrate thicknesses.The radiation in the horizontal plane of a pin array patch antenna is very small campared to that of a conventional patch antenna.And the increase of forward radiation and the decrease of backward radiation of a pin array patch antenna are tained than these conventional one's.Also the half-power beamwidth of E-plane radiation pattern of a pin array patch antenna is narrower compared to that of the conventional so that the directivity is improved.

  11. Base Station Antenna Pattern Distortion in Practical Urban Deployment Scenarios

    DEFF Research Database (Denmark)

    Rodriguez Larrad, Ignacio; Nguyen, Huan Cong; Sørensen, Troels Bundgaard;

    2014-01-01

    In real urban deployments, base station antennas are typically not placed in free space conditions. Therefore, the radiation pattern can be affected by mounting structures and nearby obstacles located in the proximity of the antenna (near-field), which are often not taken into consideration. Also...... presents a combination of near-field and far-field simulations aimed to provide an overview of the distortion experienced by the base station antenna pattern in two different urban deployment scenarios: rooftop and telecommunications tower. The study illustrates how, in comparison with the near...

  12. Improved Radiation and Bandwidth of Triangular and Star Patch Antenna

    Directory of Open Access Journals (Sweden)

    M. Ramkumar Prabhu

    2012-06-01

    Full Text Available This study presents a hexagonal shape Defected Ground Structure (DGS implemented on two element triangular patch microstrip antenna array. The radiation performance of the antenna is characterized by varying the geometry and dimension of the DGS and also by locating the DGS at specific position which were simulated. Simulation and measurement results have verified that the antenna with DGS had improved the antenna without DGS. Measurement results of the hexagonal DGS have axial ratio bandwidth enhancement of 10 MHz, return loss improvement of 35%, mutual coupling reduction of 3 dB and gain enhancement of 1 dB. A new wideband and small size star shaped patch antenna fed capacitively by a small diamond shape patch is proposed. To enhance the impedance bandwidth, posts are incorporated under the patch antenna. HFSS high frequency simulator is employed to analyze the proposed antenna and simulated results on the return loss, the E- and H-plane radiation patterns and Gain of the proposed antenna are presented at various frequencies. The antenna is able to achieve in the range of 4-8.8 GHz an impedance bandwidth of 81% for return loss of less than-10 dB.

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

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.; Sliva, Randy

    1994-01-01

    Conformal antenna arrays are popular antennas for aircraft, spacecraft and land vehicle platforms due to their inherent low weight, cost and drag properties. However, to date there has been a dearth of rigorous analytical or numerical solutions to aid the designer. In fact, it has been common practice to use limited measurements and planar approximations in designing such non-planar antennas. The finite element-boundary integral method is extended to radiation by cavity-backed structures in an infinite, metallic cylinder. The formulation is used to investigate the effect of cavity size on the radiation pattern for typical circumferentially and axially polarized patch antennas. Curvature effect on the gain, pattern shape, and input impedance is also studied. Finally, the accuracy of the FE-BI approach for a microstrip patch array is demonstrated.

  14. Antenna Pattern Impact on MIMO OTA Testing

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Franek, Ondrej;

    2013-01-01

    This paper investigates the impact of the DUT antenna pattern on the test area performance for multi-probe based MIMO OTA setup in terms of received voltage and spatial correlation. The plane wave synthesis (PWS) technique has been proposed for vertical polarization in the literature, where...... interpolation is presented. The proposed technique provides a closed form solution for the PWS when the probe ring radius is infinite. The proposed technique shows that the impact of the antenna pattern on the induced received voltage accuracy is ruled by Nyquist sampling theory. Furthermore, the impact...... of the antenna pattern on spatial correlation accuracy for prefaded signal synthesis (PFS) technique is investigated as well. Simulation and measurement results show that the number of required probes depend directly on the DUT antenna pattern. To test realistic DUTs with higher variations in directivity, we...

  15. Radiation direction control by optical slot antenna integrated with plasmonic waveguide

    Science.gov (United States)

    Park, Yeonsang; Kim, Jineun; Roh, Young-Geun; Lee, Chang-Won

    2016-04-01

    We present an optical slot antenna integrated with a metal-dielectric-metal (MIM) plasmonic waveguide. By integrating optical slot antenna on top metal layer of MIM waveguide, we can couple the plasmon guide mode into the feed antenna directly. The resonantly excited slot antenna works as a magnetic dipole and then radiates in dipole-like far-field pattern. By adding an auxiliary groove structure along with the slot antenna, the radiation can be directed into the direction where the structure determined. The demonstrated optical slot antenna integrated with a plasmonic waveguide can be used as a "plasmonic via" in plasmonic nanocircuits.

  16. Flexible Hilbert-Curve Loop Antenna Having a Triple-Band and Omnidirectional Pattern for WLAN/WiMAX Applications

    Directory of Open Access Journals (Sweden)

    Dang-Oh Kim

    2012-01-01

    Full Text Available A triple-band flexible loop antenna is proposed for WLAN/WiMAX applications in this paper. The proposed antenna is formed by the third-order Hilbert-curve and bending type structure which provides flexible characteristics. Even though the radius of the curvature for bending antennas is changed, a triple-band feature still remains in the proposed antenna. Moreover, the antenna exhibits the characteristics of omnidirectional radiation pattern and circular polarization. To verify the receiving performance of antenna, a simulation on the antenna factor was conducted by an EM simulator. Based on these results, the suggested antenna makes a noteworthy performance over typical loop antennas.

  17. Analysis of radiation performances of plasma sheet antenna

    Science.gov (United States)

    Yin, Bo; Zhang, Zu-Fan; Wang, Ping

    2015-12-01

    A novel concept of plasma sheet antennas is presented in this paper, and the radiation performances of plasma sheet antennas are investigated in detail. Firstly, a model of planar plasma antenna (PPA) fed by a microstrip line is developed, and its reflection coefficient is computed by the JE convolution finite-difference time-domain method and compared with that of the metallic patch antenna. It is found that the design of PPA can learn from the theory of the metallic patch antenna, and the impedance matching and reconstruction of resonant frequency can be expediently realized by adjusting the parameters of plasma. Then the PPA is mounted on a metallic cylindrical surface, and the reflection coefficient of the conformal plasma antenna (CPA) is also computed. At the same time, the influence of conformal cylinder radius on the reflection coefficient is also analyzed. Finally, the radiation pattern of a CPA is given, the results show that the pattern agrees well with the one of PPA in the main radiation direction, but its side lobe level has deteriorated significantly.

  18. Power conservation for reflector antennas with truncated feed patterns

    Science.gov (United States)

    Rush, W. V. T.; Cramer, P.

    1976-01-01

    Reflector-antenna calculations using idealised truncated feed patterns can lead to incorrect values of total secondary radiated power. It is demonstrated that this discrepancy is due to the presence of higher-order spherical modes incident on the reflector. When a proper spherical-wave expansion of the incident field is used, in conjunction with the physical-optics technique, to determine the scattered field, the total power of the scattered field will equal the power radiated by the feed.

  19. Metallic Photonic Bandgap Resonant Antennas with High Directivity and High Radiation Resistance

    Institute of Scientific and Technical Information of China (English)

    林青春; 符建; 何赛灵; 章坚武

    2002-01-01

    A metallic photonic bandgap (MPBG) resonant antenna is introduced, which has novel characteristics (such as high directivity and high radiation resistance for a certain range of frequencies) as compared to conventional MPBG antennas. The linear MPBG resonant antenna is formed by infinitely long metallic rods in vacuum. The numerical results for the radiation pattern and the radiation resistance are presented. By adjusting the struct ure of the MPBG resonant antenna and its working frequency, an optimal structure is achieved. The physical reasons for the novel characteristics of the MPBG resonant antenna are also explained.

  20. Performances study of UWB monopole antennas using half-elliptic radiator conformed on elliptical surface

    Science.gov (United States)

    Djidel, S.; Bouamar, M.; Khedrouche, D.

    2016-04-01

    This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.

  1. Radiation Analysis and Characteristics of Conformal Reflectarray Antennas

    Directory of Open Access Journals (Sweden)

    Payam Nayeri

    2012-01-01

    Full Text Available This paper investigates the feasibility of designing reflectarray antennas on conformal surfaces. A generalized analysis approach is presented that can be applied to compute the radiation performance of conformal reflectarray antennas. Using this approach, radiation characteristics of conformal reflectarray antennas on singly curved platforms are studied and the performances of these designs are compared with planar designs. It is demonstrated that a conformal reflectarray antenna can be a suitable choice for applications requiring high-gain antennas on curved platforms.

  2. Radiation characteristics of input power from surface wave sustained plasma antenna

    Science.gov (United States)

    Naito, T.; Yamaura, S.; Fukuma, Y.; Sakai, O.

    2016-09-01

    This paper reports radiation characteristics of input power from a surface wave sustained plasma antenna investigated theoretically and experimentally, especially focusing on the power consumption balance between the plasma generation and the radiation. The plasma antenna is a dielectric tube filled with argon and small amount of mercury, and the structure is a basic quarter wavelength monopole antenna at 2.45 GHz. Microwave power at 2.45 GHz is supplied to the plasma antenna. The input power is partially consumed to sustain the plasma, and the remaining part is radiated as a signal. The relationship between the antenna gain and the input power is obtained by an analytical derivation and numerical simulations. As a result, the antenna gain is kept at low values, and most of the input power is consumed to increase the plasma volume until the tube is filled with the plasma whose electron density is higher than the critical electron density required for sustaining the surface wave. On the other hand, the input power is consumed to increase the electron density after the tube is fully filled with the plasma, and the antenna gain increases with increasing the electron density. The dependence of the antenna gain on the electron density is the same as that of a plasma antenna sustained by a DC glow discharge. These results are confirmed by experimental results of the antenna gain and radiation patterns. The antenna gain of the plasma is a few dB smaller than that of the identical metal antenna. The antenna gain of the plasma antenna is sufficient for the wireless communication, although it is difficult to substitute the plasma antenna for metal antennas completely. The plasma antenna is suitable for applications having high affinity with the plasma characteristics such as low interference and dynamic controllability.

  3. Short-wave band linear antenna array consisting of 'butterfly' radiators

    OpenAIRE

    Kudzin, Viktor P.; Lozovsky, V. N.; N.I. Shlyk

    2011-01-01

    The broadband linear antenna array of vertical polarisation for a short-wave band operation consisting of "butterfly" radiators is offered. The given radiator represents the modified flat wire antenna. The one-sided radiation pattern is provided by means of aperiodic reflector.The specific feature of the offered array is that the adjacent radiators are galvanic connected with each other. It provides improvement of radio engineering characteristics and obvious constructive and economic advanta...

  4. Scattering and radiation from cylindrically conformal antennas

    Science.gov (United States)

    Kempel, Leo Charles

    Microstrip patch antennas offer considerable advantages in terms of weight, aerodynamic drag, cost, flexibility, and observability over more conventional protruding antennas. Two hybrid finite element methods are presented and are used to examine the scattering and radiation behavior of cylindrically conformal patches. In conjunction with a new divergence-free cylindrical shell element, the finite element-boundary integral method is shown to have low computational and memory requirements when compared with competing approaches. This method uses an efficient creeping wave series for the computation of the dyadic Green's function and a uniform surface mesh so that a fast Fourier transform may be used to reduce the computational and memory burden of the method. An alternative finite element-absorbing boundary condition approach incorporates a new conformal vector condition which minimizes the computational domain. The latter method is more flexible than the former because it can incorporate surface coatings and protruding antennas. Guidelines are established for minimal ABC displacement from the aperture. These two hybrid finite element methods are used to study the scattering, radiation, and input impedance of typical conformal antenna arrays. In particular, the effect of curvature and cavity size is examined for both discrete and wraparound antenna arrays.

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

    DEFF Research Database (Denmark)

    Peng, Liang; Mortensen, N. Asger

    2014-01-01

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

  6. Antenna-coupled thin-film far-infrared radiation detectors

    Science.gov (United States)

    Yasuoka, Yoshizumi; Kobayashi, Hiroaki; Shimizu, Takashi

    1996-06-01

    The 4 slot array antenna for 700 GHz far-infrared radiation are fabricated on the fused quartz substrates, making use of the dimensions obtained from the model experiments in the microwave region, and the power gain and directivity are obtained experimentally. The properties of fabricated array antenna agree with the theory, and 4 slot array antenna on the substrate of which thickness is odd multiples of a quarter dielectric wavelength improve the power gain by 5 dB compared with the single slot antenna on both sides of air and dielectric. These experimental data indicate that the fabricated antennas show the antenna pattern expected from the theory and work as array antennas for 700 GHz far- infrared laser radiation.

  7. Numerical analysis of a dielectric rod antenna - demonstration of the discontinuity-radiation concept

    OpenAIRE

    Ando, Takashi; Yamauchi, Junji; Nakano, Hisamatsu

    2003-01-01

    A technique combining the finite-difference time-domain method and the imaginary-distance beam-propagation method is used to demonstrate the discontinuity-radiation concept for a dielectric rod antenna. The field near the rod is decomposed into a guided and an unguided wave. Using the two waves, the feed and terminal patterns are evaluated. It is numerically revealed that superposing the two patterns forms the radiation field of the antenna. The decomposition technique enables us to efficient...

  8. Understanding and optimizing microstrip patch antenna cross polarization radiation on element level for demanding phased array antennas in weather radar applications

    Science.gov (United States)

    Vollbracht, D.

    2015-11-01

    The antenna cross polarization suppression (CPS) is of significant importance for the accurate calculation of polarimetric weather radar moments. State-of-the-art reflector antennas fulfill these requirements, but phased array antennas are changing their CPS during the main beam shift, off-broadside direction. Since the cross polarization (x-pol) of the array pattern is affected by the x-pol element factor, the single antenna element should be designed for maximum CPS, not only at broadside, but also for the complete angular electronic scan (e-scan) range of the phased array antenna main beam positions. Different methods for reducing the x-pol radiation from microstrip patch antenna elements, available from literature sources, are discussed and summarized. The potential x-pol sources from probe fed microstrip patch antennas are investigated. Due to the lack of literature references, circular and square shaped X-Band radiators are compared in their x-pol performance and the microstrip patch antenna size variation was analyzed for improved x-pol pattern. Furthermore, the most promising technique for the reduction of x-pol radiation, namely "differential feeding with two RF signals 180° out of phase", is compared to single fed patch antennas and thoroughly investigated for phased array applications with simulation results from CST MICROWAVE STUDIO (CST MWS). A new explanation for the excellent port isolation of dual linear polarized and differential fed patch antennas is given graphically. The antenna radiation pattern from single fed and differential fed microstrip patch antennas are analyzed and the shapes of the x-pol patterns are discussed with the well-known cavity model. Moreover, two new visual based electromagnetic approaches for the explanation of the x-pol generation will be given: the field line approach and the surface current distribution approach provide new insight in understanding the generation of x-pol component in microstrip patch antenna radiation

  9. Physical bounds for antenna radiation efficiency

    CERN Document Server

    Shahpari, Morteza

    2016-01-01

    Small volume, reduced conductivity and high frequencies are major imperatives in the design of communications infrastructure. The radiation efficiency $\\eta_r$ impacts on the optimal gain, quality factor, and bandwidth. The current efficiency limit applies to structures confined to a radian sphere $ka$ ($k$ is the wave number, $a$ is the radius). Here we present new absolute limits to $\\eta_r$ for arbitrary antenna shapes based on $k^2S$ where $S$ is the conductor surface area. For an electrical length of $10^{-5}$ our result is four orders of magnitude closer to the analytical solution. The improved bound on $\\eta_r$ is more accurate, more general, and easier to calculate than other limits. It is based on the total surface area of the conductors and provides greatly improved estimations for electrically small radiators at very low frequencies. The work is of great benefit to antenna designers assessing new materials such as conductive polymers.

  10. The investigation of radiation characteristics of Fresnel antenna for Q-band

    OpenAIRE

    Magro, V. I.; Morozov, V M

    2003-01-01

    The general approach to analysis of zonal Fresnel antenna is considered. The frequency characteristics of Fresnel antenna are analyzed. The radiation characteristics of the Fresnel antenna are considered.

  11. Design and Implementation of Radiation Pattern Reconfigurable Planar Microstrip Antenna%方向图可重构的平面准八木天线的设计与实现

    Institute of Scientific and Technical Information of China (English)

    汪圣杰; 顾涓涓; 胡国华

    2016-01-01

    The development of wireless communication system has raise higher demand on the perform-ance of antenna,the radiation pattern reconfigurable antenna is widely needed in wireless communica-tion system.In this paper the radiation pattern reconfigurable microstrip antenna has been designed and realized.This structure is based on traditional dipole antenna and Yagi antenna.According to dif-ferential feeding theory,the two arms which consist of the driven dipole are loaded on each side of sub-strate.A PIN diode switch is loaded between the ground and each driven dipole arm a PIN diode switch is loaded between the feed and the other driven dipole arm.The antenna radiation pattern can be reconfigurable by combination controlling the diode switch state.The result shows that the return loss is -25dB at center frequency.-10dB bandwidth is about 320MHz,relative bandwidth is about 13%.The maximum gain at main radiation direction reaches 3dB.This reconfigurable antenna has good directivity with the scanning function of eight direction and can be applied in wireless communi-cation system.%通信系统的快速发展对天线的性能提出了更高的要求,方向图可重构天线是天线家族中重要组成部分之一,应用十分广泛。文中利用 HFSS 软件对方向图可重构的平面准八木天线进行了设计与实现,天线结构基于传统的偶极子天线以及八木天线并采用差分馈电,主天线振子置于介质板的两侧,在地板一侧的振子臂通过PIN 二极管开关与地板相连,馈电一侧的阵子臂通过 PIN 二极管开关与馈电相连。通过组合控制二极管的开关状态即可控制天线单元的工作状态从而实现天线方向图可重构的目的。结果表明天线的回波损耗在中心频点出达到-25dB,-10dB 带宽为约为400MHz,相对带宽为13%,天线在主辐射方向的增益达到约4.5dB,该天线能够实现4个方向的扫描,具有良好的方向性。

  12. Antenna measurement on the radiator component of an X-band Vlasov-type mode converter

    Science.gov (United States)

    Ruth, Brian G.; Schlesiger, Christian D. R.; Dahlstrom, Robert K.

    1989-07-01

    This paper addresses the radiation patterns launched from circular waveguide radiators as the first step in the design of a Vlasov-type mode converter that will function at high power levels in the X-band frquency range (8 to 12 GHz). The radiating ends of the radiators are each cut at a specific angle relative to the center axis of the waveguide to form the waveguide launcher component of a Vlasov-type mode converter. The far-field radiation patterns for three radiators were measured with an antenna pattern-mapping system.

  13. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

    Science.gov (United States)

    Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

    2015-01-01

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch. PMID:26690443

  14. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    Directory of Open Access Journals (Sweden)

    Seung-Hyun Eom

    2015-12-01

    Full Text Available In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT switch and a balun element. A double-sided parallel-strip line (DSPSL is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  15. A New Agile Radiating System Called Electromagnetic Band Gap Matrix Antenna

    Directory of Open Access Journals (Sweden)

    Hussein Abou Taam

    2014-01-01

    Full Text Available Civil and military applications are increasingly in need for agile antenna devices which respond to wireless telecommunications, radars, and electronic warfare requirements. The objective of this paper is to design a new agile antenna system called electromagnetic band gap (EBG matrix. The working principle of this antenna is based on the radiating aperture theory and constitutes the subject of an accepted CNRS patent. In order to highlight the interest and the originality of this antenna, we present a comparison between it and a classical patch array only for the (one-dimensional 1D configuration by using a rigorous full wave simulation (CST Microwave software. In addition, EBG matrix antenna can be controlled by specific synthesis algorithms. These algorithms use inside their; optimization loop an analysis procedure to evaluate the radiation pattern. The analysis procedure is described and validated at the end of this paper.

  16. Automatic reference level control for an antenna pattern recording system

    Science.gov (United States)

    Lipin, R., Jr.

    1971-01-01

    Automatic gain control system keeps recorder reference levels within 0.2 decibels during operation. System reduces recorder drift during antenna radiation distribution determinations over an eight hour period.

  17. Effect of random surface errors on radiation characteristics of the side-fed offset Cassegrain antenna

    Institute of Scientific and Technical Information of China (English)

    LIU Shao-dong; JIAO Yong-chang; ZHANG Fu-shun

    2006-01-01

    In this paper the average power pattern of the side-fed offset Cassegrain (SFOC) dual reflector antenna is analyzed,and the effect of the random surface error on radiation characteristics of the antenna is introduced.Here,the random surface error is defined as the error of the standard reflector in its normal direction and the errors in a small zone of the reflector are considered as equal.We also assume that the phase error on the aperture led by the random surface error obeys a Gaussian distribution with zero mean,under which the expression of the average power pattern is deduced.Finally,the data related to the radiation characteristics of the antenna are calculated and the corresponding curves are presented.The obtained results can be used for the user to determine the manufacturing accuracy of the reflector of the SFOC antennas.

  18. Design, Analysis, and Verification of Ka-Band Pattern Reconfigurable Patch Antenna Using RF MEMS Switches

    Directory of Open Access Journals (Sweden)

    Zhongliang Deng

    2016-08-01

    Full Text Available This paper proposes a radiating pattern reconfigurable antenna by employing RF Micro-electromechanical Systems (RF MEMS switches. The antenna has a low profile and small size of 4 mm × 5 mm × 0.4 mm, and mainly consists of one main patch, two assistant patches, and two RF MEMS switches. By changing the RF MEMS switches operating modes, the proposed antenna can switch among three radiating patterns (with main lobe directions of approximately −17.0°, 0° and +17.0° at 35 GHz. The far-field vector addition model is applied to analyse the pattern. Comparing the measured results with analytical and simulated results, good agreements are obtained.

  19. A simple UWB monopole antenna using half-elliptical radiator

    OpenAIRE

    Liu, L.; Sun, YY; Yang, XJ; Cheung, SW

    2013-01-01

    This paper presents the results of a simple ultrawideband (UWB) monopole antenna having an impedance bandwidth from 3.1-40 GHz. The antenna has a half-elliptical shaped radiator with microstrip-fed and a total size of 24×30×0.762 mm3. The extremely wideband characteristic of the antenna is achieved by simply using a tapered transformer and a small square slot on the ground plane. © 2013 IEEE.

  20. Analysis and design of plasma monopole antenna

    OpenAIRE

    Wei, Li; Jinghui, Qiu; Ying, Suo

    2009-01-01

    Two kinds of plasma monopole antennas are simulated and analyzed in this article. For different radius, reflection coefficient, radiation pattern and radiation efficiency of a cylindrical plasma monopole antenna are calculated respectively. According to actual situation, a conical plasma monopole antenna with different cone angle is simulated. Impedance and radiation characteristics of the plasma antenna are similar to the metal monopole antenna.

  1. Terahertz radiation from armchai rcarbon nanotube dipole antenna

    Institute of Scientific and Technical Information of China (English)

    Wang Yue; Wu Qun; He Xun-Jun; Zhang Shao-Qing; Zhuang Lei-Lei

    2009-01-01

    This paper investigates the electromagnetic radiation characteristics of a metallic, large aspect ratio single walled carbon nanotube antenna in the terahertz frequency region below 12.5 THz. The key features of terahertz pulse have been revealed on the carbon nanotube antenna in comparison with conventional photoconductive switching. The terahertz waveforms, radiation power and their field distributions have been evaluated and are analysed. The Fourier transformed spectra over the whole frequency range demonstrate that the carbon nanotube antenna can be used as radiation source for broadband terahertz applications.

  2. 频率与方向图可重构锯齿偶极子微带天线的设计%Design of reconfigurable frequency and radiation pattern saw-tooth-dipole micro-strip antenna

    Institute of Scientific and Technical Information of China (English)

    曹卫平; 蔡彬

    2014-01-01

    In order to meet high date rate wireless services and the miniaturization of the micro-strip antenna,a printed planar micro-strip fed saw-tooth dipole antenna with reconfigurable frequency and pattern properties is designed for wireless com-munication.The structure consists of two saw-tooth dipoles,each one is printed on one substrate layer.The saw-tooth di-pole can achieve its frequency and pattern reconfigurable function by changing the operating state of the PIN diode to trans-form the local structure and the distribution of surface current.Experimental results show that the antenna can achieve the function reconfigurable in the range of 1.88-2.85 GHz,which covers the main wireless communication band.During the op-erating band,an omni-directional radiation pattern in H-plane is well reached and the beam scanning in E-plane pattern is a-chieved.%为了满足无线通信高速数据需求和微带天线的小型化,设计了一种频率和方向图可重构锯齿偶极子微带天线,该天线包括2个锯齿状振子,分别印制在介质板的两面。通过改变锯齿振子上PIN二极管的工作状态,使天线的局部结构和表面电流分布发生变化,实现天线频率和方向图的可重构。实验结果表明,该天线在1.88~2.85 GHz 频段内实现可重构的功能,覆盖了主要的无线通信频带。在工作频段内,天线的 H 面方向图具有全向特性,E面方向图实现了波束扫描。

  3. Design Tri-band Rectangular Patch Antenna for Wi-Fi, Wi-Max and WLAN in Military Band Applications with Radiation Pattern Suppression

    Directory of Open Access Journals (Sweden)

    Aymen Dheyaa Khaleel

    2015-08-01

    Full Text Available Design tri-band rectangular patch antenna is presented. This research study focuses on designing an antenna that can operate with three bands; 2.4, 3.5 and 4.4 GHz, respectively. These bands are accepted by Wi-Fi, Wi-MAX and WLAN in Military band applications. The shape of the proposed design is based on simple rectangular patches with inset-feed on one surface of the FR4 substrate. On the other surface of FR4 substrate, is the infinite ground plane. Also Computer Simulation Technology (CST microwave studio 2012 is used for the design of antenna. This design is fabricated using photolithographic process.

  4. Radiation quality factor of spherical antennas with material cores

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  5. Current Situation and Development Trend of Inflight Antenna Pattern Measurement Techniques of Spaceborne SAR

    Directory of Open Access Journals (Sweden)

    Hong Jun

    2012-09-01

    Full Text Available The antenna pattern uncertainty is the main error of SAR system. The technique for inflight antenna pattern measurement of spaceborne SAR is one of the most important technique of SAR calibration. This paper discusses the development courses of the inflight antenna pattern measurement of spaceborne SAR, analyses its development trend and compares the main inflight antenna pattern measurement techniques. This paper will be an important reference for designing a project of inflight antenna pattern measurement of spaceborne SAR.

  6. RESEARCH ON INDOOR ELECTROMAGNETIC RADIATION FIELD OF MULTIPLE ANTENNA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Ma Li; Lu Yanhui; Zou Peng; Zhou Xiaoping

    2012-01-01

    The complexity of the indoor environment brings great challenges to predict the electromagnetic radiation field of multiple antenna systems.Based on the Finite Difference Time Domain (FDTD) algorithm,using the mobile phone shielding device as the multiple antenna systems example,the mobile phone shielding device's indoor electromagnetic radiation field is researched by measurment method and simulation method.The effectivity of prediction method is verified by comparing the prediciton results with the measurment results.About 80% of the error can be controlled less than ±4 dB.The quantitative research has certain guiding significance to the prediction of the multiple antenna systems radio wave propagation.

  7. Computation of antenna pattern correlation and MIMO performance by means of surface current distribution and spherical wave theory

    Directory of Open Access Journals (Sweden)

    O. Klemp

    2006-01-01

    Full Text Available In order to satisfy the stringent demand for an accurate prediction of MIMO channel capacity and diversity performance in wireless communications, more effective and suitable models that account for real antenna radiation behavior have to be taken into account. One of the main challenges is the accurate modeling of antenna correlation that is directly related to the amount of channel capacity or diversity gain which might be achieved in multi element antenna configurations. Therefore spherical wave theory in electromagnetics is a well known technique to express antenna far fields by means of a compact field expansion with a reduced number of unknowns that was recently applied to derive an analytical approach in the computation of antenna pattern correlation. In this paper we present a novel and efficient computational technique to determine antenna pattern correlation based on the evaluation of the surface current distribution by means of a spherical mode expansion.

  8. Receiving Properties of Thin-Film Slot Antenna Arrays for 28-THz-CO2 Laser Radiation

    Science.gov (United States)

    Uchida, Takashi; Abe, Yasuhiko; Hashimoto, Shoji; Yasuoka, Yoshizumi

    The receiving properties of fabricated parasitic slot antenna arrays on ZnS dielectric substrates for 28-THz-CO2 laser radiation were investigated. When the CO2 laser beam was irradiated on the antennas directly (from the air-side), the E-plane antenna patterns of the parasitic slot antenna arrays became increasing sharper as the number of slots in the array increased from 1to 7. On the other hand, the H-plane antenna patterns did not change with the number of slots because the slot antennas were not arrayed in the H-plane. It was found that the antenna theory based on the transmission line model was applicable at 28 THz. When the CO2 laser beam was irradiated through the substrate (from the substrate-side), rippled antenna patterns were observed due to multiple reflection in the substrate because the thickness of the substrate was much longer than the dielectric wavelength of the CO2 laser. It was also found that the antenna receiving properties were affected by the thickness of the substrate. Furthermore, as expected from the theory, the power gain of the 7-parasitic slot antenna array improved by approximately 7 dB compared to that of the single-slot antenna at 28 THz.

  9. Pattern Synthesis of Dual-band Shared Aperture Interleaved Linear Antenna Arrays

    Directory of Open Access Journals (Sweden)

    H. Guo

    2014-09-01

    Full Text Available This paper presents an approach to improve the efficiency of an array aperture by interleaving two different arrays in the same aperture area. Two sub-arrays working at different frequencies are interleaved in the same linear aperture area. The available aperture area is efficiently used. The element positions of antenna array are optimized by using Invasive Weed Optimization (IWO to reduce the peak side lobe level (PSLL of the radiation pattern. To overcome the shortness of traditional methods which can only fulfill the design of shared aperture antenna array working at the same frequency, this method can achieve the design of dual-band antenna array with wide working frequency range. Simulation results show that the proposed method is feasible and efficient in the synthesis of dual-band shared aperture antenna array.

  10. Antenna Beam Pattern Modulation with Lattice Reduction Aided Detection

    OpenAIRE

    Ramirez-Gutierrez, R; Zhang, LX; Elmirghani, J

    2015-01-01

    This paper introduces a novel transmission design for antenna beam pattern modulation (ABPM) with a low complexity decoding method. The concept of ABPM was first presented with the optimal maximum likelihood (ML) decoding. However, an ML detector may not be viable for practical systems when the constellation size or the number of antennas is large such as in massive multiple input multiple output (MIMO) systems. Linear detectors, on the other hand, have lower complexity but inferior performan...

  11. Near Field Radiation Characteristics of Implantable Square Spiral Chip Inductor Antennas for Bio-Sensors

    Science.gov (United States)

    Nessel, James A.; Simons, Rainee N.; Miranda, Felix A.

    2007-01-01

    The near field radiation characteristics of implantable Square Spiral Chip Inductor Antennas (SSCIA) for Bio-Sensors have been measured. Our results indicate that the measured near field relative signal strength of these antennas agrees with simulated results and confirm that in the near field region the radiation field is fairly uniform in all directions. The effects of parameters such as ground-plane, number of turns and microstrip-gap width on the performance of the SSCIA are presented. Furthermore, the SSCIA antenna with serrated ground plane produce a broad radiation pattern, with a relative signal strength detectable at distances within the range of operation of hand-held devices for self-diagnosis.

  12. 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...... inherently decoupled when integrated on the same handset, while also other parameters such as frequency duplex distance and interaction with the users body influence the mutual coupling....

  13. Radar transponder antenna pattern analysis for the space shuttle

    Science.gov (United States)

    Radcliff, Roger

    1989-01-01

    In order to improve tracking capability, radar transponder antennas will soon be mounted on the Shuttle solid rocket boosters (SRB). These four antennas, each being identical cavity-backed helices operating at 5.765 GHz, will be mounted near the top of the SRB's, adjacent to the intertank portion of the external tank. The purpose is to calculate the roll-plane pattern (the plane perpendicular to the SRB axes and containing the antennas) in the presence of this complex electromagnetic environment. The large electrical size of this problem mandates an optical (asymptotic) approach. Development of a specific code for this application is beyond the scope of a summer fellowship; thus a general purpose code, the Numerical Electromagnetics Code - Basic Scattering Code, was chosen as the computational tool. This code is based on the modern Geometrical Theory of Diffraction, and allows computation of scattering of bodies composed of canonical problems such as plates and elliptic cylinders. Apertures mounted on a curved surface (the SRB) cannot be accomplished by the code, so an antenna model consisting of wires excited by a method of moments current input was devised that approximated the actual performance of the antennas. The improvised antenna model matched well with measurements taken at the MSFC range. The SRB's, the external tank, and the shuttle nose were modeled as circular cylinders, and the code was able to produce what is thought to be a reasonable roll-plane pattern.

  14. Feature in Antenna Pattern for Pointing and Orientation Determination

    Science.gov (United States)

    Rochblatt, David (Inventor)

    2016-01-01

    Systems and methods for antenna pointing are disclosed. A transmit antenna system having an adjustable boresight transmits a signal exhibiting a far-field pattern including a feature (e.g. a V-Notch) in a polarization of the signal disposed at a fixed position off a beam peak of the far-field pattern of the signal. A receive antenna system scans across the far-field pattern of the signal in the polarization to locate the feature and determine a pointing error of the adjustable boresight therefrom. The system may be applied to a cross-polarization of the signal where a co-polarization of the signal is simultaneously used for telecommunication.

  15. Scan Performance and Reconfigurability of Agile Radiating Matrix Antenna Prototype

    Directory of Open Access Journals (Sweden)

    H. Abou Taam

    2015-01-01

    Full Text Available This paper is dedicated to different experimental validations concerning a novel concept of beam forming and beam steering antenna. The working principle of the antenna is based on the equivalent radiating surface approach and inspired from an electromagnetic band gap antenna. The theoretical aspect and some numerical validations have been already published in the work of Abou Taam et al. (2014. Different electromagnetic behaviors have been demonstrated, such as low mutual coupling, and high gain preservation for high scanning angles values. In this paper, some of these electromagnetic behaviors will be proven experimentally by the means of two different feeding configurations.

  16. Characterizing Impulse Radiating Antennas by an Intuitive Approach

    Science.gov (United States)

    Sachs, J.; Peyer, P.; Rauschenbach, P.; Tkac, F.; Zetik, R.

    Referring to UWB-sensor applications and impulse radio, the ideal behavior of impulse radiating antennas will be summarized and some new characteristic functions will be introduced. The time domain Friis-formula will be derived based on normalized guided and free waves. By using the p-norm, a method is introduced to define the characteristic values and functions which can either refer to an antenna or yet the whole transmission chain.

  17. Propagation of Surface Wave Along a Thin Plasma Column and Its Radiation Pattern

    Institute of Scientific and Technical Information of China (English)

    WANG Zhijiang; ZHAO Guowei; XU Yuemin; LIANG Zhiwei; XU Jie

    2007-01-01

    Propagation of the surface waves along a two-dimensional plasma column and the far-field radiation patterns are studied in thin column approximation. Wave phase and attenuation coefficients are calculated for various plasma parameters. The radiation patterns are shown. Results show that the radiation patterns are controllable by flexibly changing the plasma length and other parameters in comparison to the metal monopole antenna. It is meaningful and instructional for the optimization of the plasma antenna design.

  18. A truncation method for modelling effective antenna patterns in urban areas

    NARCIS (Netherlands)

    Mantel, O.C.; Rijken, M.; Matic, D.; Mawira, A.

    2004-01-01

    Signal level predictions for sector antennas in mobile networks strongly depend on the antenna pattern used in the prediction tool. For built-up areas, reflections and scattering often lead to a significant energy component at the back of the antenna, and the theoretical antenna pattern does not acc

  19. Comparative Analysis of Linear and Nonlinear Pattern Synthesis of Hemispherical Antenna Array Using Adaptive Evolutionary Techniques

    Directory of Open Access Journals (Sweden)

    K. R. Subhashini

    2014-01-01

    synthesis is termed as the variation in the element excitation amplitude and nonlinear synthesis is process of variation in element angular position. Both ADE and AFA are a high-performance stochastic evolutionary algorithm used to solve N-dimensional problems. These methods are used to determine a set of parameters of antenna elements that provide the desired radiation pattern. The effectiveness of the algorithms for the design of conformal antenna array is shown by means of numerical results. Comparison with other methods is made whenever possible. The results reveal that nonlinear synthesis, aided by the discussed techniques, provides considerable enhancements compared to linear synthesis.

  20. Radiation of planar stripline ultra-wideband antenna for WPAN systems

    OpenAIRE

    Garbaruk, M.

    2007-01-01

    The paper presents results of design and computer simulation of planar monopole pulse ultra-wideband (UWB) antenna for WPAN applications. A complex approach to design of UWB antennas was used. Problem of radiation of UWB signals by the antenna was discussed. Electric fields radiated by the antenna for chosen directions were calculated and shown.

  1. Shaping and resizing of multifed slot radiators used in conformal microwave antenna arrays for hyperthermia treatment of large superficial diseases.

    Science.gov (United States)

    Maccarini, Paolo F; Arunachalam, Kavitha; Juang, Titania; De Luca, Valeria; Rangarao, Sneha; Neumann, Daniel; Martins, Carlos Daniel; Craciunescu, Oana; Stauffer, Paul R

    2009-01-01

    It has been recently shown that chestwall recurrence of breast cancer and many other superficial diseases can be successfully treated with the combination of radiation, chemotherapy and hyperthermia. Conformal microwave antenna array for hyperthermia treatment of large area superficial diseases can significantly increase patient comfort while at the same time facilitate treatment of larger and more irregularly shaped disease. A large number of small efficient antennas is preferable for improved control of heating, as the disease can be more accurately contoured and the lower power requirement correlates with system reliability, linearity and reduced cost. Thus, starting from the initially proposed square slot antennas, we investigated new designs for multi-fed slot antennas of several shapes that maximize slot perimeter while reducing radiating area, thus increasing antenna efficiency. Simulations were performed with commercial electromagnetic simulation software packages (Ansoft HFSS) to demonstrate that the antenna size reduction method is effective for several dual concentric conductor (DCC) aperture shapes and operating frequencies. The theoretical simulations allowed the development of a set of design rules for multi-fed DCC slot antennas that facilitate conformal heat treatments of irregular size and shape disease with large multi-element arrays. Independently on the shape, it is shown that the perimeter of 10cm at 915 MHz delivers optimal radiation pattern and efficiency. While the maximum radiation is obtained for a circular pattern the rectangular shape is the one that feels more efficiently the array space.

  2. Shaping and resizing of multifed slot radiators used in conformal microwave antenna arrays for hyperthermia treatment of large superficial diseases.

    Science.gov (United States)

    Maccarini, Paolo F; Arunachalam, Kavitha; Juang, Titania; De Luca, Valeria; Rangarao, Sneha; Neumann, Daniel; Martins, Carlos Daniel; Craciunescu, Oana; Stauffer, Paul R

    2009-01-01

    It has been recently shown that chestwall recurrence of breast cancer and many other superficial diseases can be successfully treated with the combination of radiation, chemotherapy and hyperthermia. Conformal microwave antenna array for hyperthermia treatment of large area superficial diseases can significantly increase patient comfort while at the same time facilitate treatment of larger and more irregularly shaped disease. A large number of small efficient antennas is preferable for improved control of heating, as the disease can be more accurately contoured and the lower power requirement correlates with system reliability, linearity and reduced cost. Thus, starting from the initially proposed square slot antennas, we investigated new designs for multi-fed slot antennas of several shapes that maximize slot perimeter while reducing radiating area, thus increasing antenna efficiency. Simulations were performed with commercial electromagnetic simulation software packages (Ansoft HFSS) to demonstrate that the antenna size reduction method is effective for several dual concentric conductor (DCC) aperture shapes and operating frequencies. The theoretical simulations allowed the development of a set of design rules for multi-fed DCC slot antennas that facilitate conformal heat treatments of irregular size and shape disease with large multi-element arrays. Independently on the shape, it is shown that the perimeter of 10cm at 915 MHz delivers optimal radiation pattern and efficiency. While the maximum radiation is obtained for a circular pattern the rectangular shape is the one that feels more efficiently the array space. PMID:24352575

  3. Numerical modeling of HF skywave radiation from antennas in irregular terrain

    Energy Technology Data Exchange (ETDEWEB)

    Burke, G.J.

    1990-11-01

    The problem of computing the radiation pattern of an HF antenna sited in irregular terrain was investigated. The primary interest is in antennas for skywave communication, however ionospheric models were not considered. Several methods for modeling terrain effects are briefly reviewed. A geometrical optics model for arbitrary terrain is developed and results are compared with published results from solution of a Volterra integral equation for scattering by a Gaussian ridge. This report covers work on the first phase of a project for the US Navy to develop and apply models for terrain effects in HF communications involving skywave. 45 refs., 16 figs.

  4. Design of compact electromagnetic impulse radiating antenna for melanoma treatment.

    Science.gov (United States)

    Arockiasamy, Petrishia; Mohan, Sasikala

    2016-01-01

    Cancer therapy is one of the several new applications which use nanosecond and subnanosecond high voltage pulses. New treatment based on electromagnetic (EM) fields have been developed as non-surgical and minimally invasive treatments of tumors. In particular, subnanosecond pulses can introduce important non-thermal changes in cell biology, especially the permeabilization of the cell membrane. The motivation behind this work is to launch intense subnanosecond pulses to the target (tumors) non-invasively. This works focuses on the design of a compact intense pulsed EM radiating antenna. In tense EM waves radiated at the first focal point of the Prolate Spheroidal Reflector (PSR) are focused at the second focal point where the target (tumor) is present. Two antennas with PSR but fed with different compact wave radiator are designed to focus pulsed field at the second focal point. The PSR with modified bicone antenna feed and PSR with elliptically tapered horn antenna feed are designed. The design parameters and radiation performance are discussed. PMID:25651405

  5. Use of Admittance-Wall Models in Analysis of Radiating Line Antennas

    Science.gov (United States)

    Tammen, David John

    This thesis describes the development of analytical models for two radiating line antenna structures: the traveling -wave microstrip antenna and the Annular Sector Radiating Line (ANSERLIN) antenna. The models provide data and insights into the operation of the antennas without requiring large amounts of computation. It was shown that the general characteristics of the radiation patterns of ANSERLIN elements can be obtained using only a small number of circularly polarized spherical modes in the field expansion. A first -order model is obtained by solving for the fields of a closed waveguide with perfect electric conducting (PEC) top and bottom walls and perfect magnetic conducting (PMC) side walls. The propagation constant obtained from these fields of the closed waveguide is then used in the equivalent magnetic current filaments to obtain the radiated fields. Use of the propagation constant of the closed waveguide fields does not include the fringing and radiation behavior. A second-order model was developed in which the radiation loss and fringing fields are included by putting a small complex admittance on the side walls rather than having PMC side walls. Two formulations were developed to include the radiation loss in the representation: a coupled-mode formulation and an eigenvalue formulation. The coupled -mode formulation, which is similar to that described by Schelkunoff for a waveguide with lossy conductors, is used to obtain the complex-valued propagation constant. In the eigenvalue formulation, the eigenvalues obtained from the solution of the characteristic equation of the waveguide with admittance side walls are used to obtain the complex -valued propagation constant. This complex-valued propagation constant, which includes the fringing and radiation behavior, is then used in the equivalent magnetic current filaments to obtain the radiated fields. Good agreement was found between measured results and results computed using the eigenvalue formulation

  6. Low-Gain Circularly Polarized Antenna with Torus-Shaped Pattern

    Science.gov (United States)

    Amaro, Luis R.; Kruid, Ronald C.; Vacchione, Joseph D.; Prata, Aluizio

    2012-01-01

    bicone fs aperture increases, the gain increase becomes less until one reaches a point of diminishing returns. In order to overcome this problem, a shaped aperture is used. Rather than the standard linear bicone, a parabolic bicone was found to reduce the amount of phase variation as the aperture increases. In fact, the phase variation is half of the standard linear bicone, which leads to higher gain with smaller aperture sizes. The antenna pattern radiated from this parabolic-shaped bicone antenna has fairly high side lobes. The Juno project requested that these sidelobes be minimized. This was accomplished by adding corrugations to the parabolic shape. This corrugated-shaped bicone antenna had reasonably low sidelobes, and the appropriate gain and beamwidth to meet project requirements.

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

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

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

  8. Nano-antennae assisted emission of extreme ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Pfullmann, Nils; Noack, Monika; Cardoso de Andrade, Jose; Rausch, Stefan; Nagy, Tamas; Kovacev, Milutin [Leibniz Universitaet Hannover, Quantum Optics Institute (Germany); QUEST Centre for Quantum Engineering and Space-Time Research, Hannover (Germany); Reinhardt, Carsten [Laser Zentrum Hannover (Germany); Knittel, Vanessa; Bratschitsch, Rudolf; Leitenstorfer, Alfred [University of Konstanz, Department of Physics and Center for Applied Photonics (Germany); Akemeier, Dieter; Huetten, Andreas [Universitaet Bielefeld, AG Duenne Schichten Physik der Nanostrukturen (Germany); Morgner, Uwe [Leibniz Universitaet Hannover, Quantum Optics Institute (Germany); QUEST Centre for Quantum Engineering and Space-Time Research, Hannover (Germany); Laser Zentrum Hannover (Germany)

    2014-04-15

    High-order harmonic generation in xenon with oscillator repetition rates is studied. The necessary intensity is reached via plasmonic field enhancement at nanostructured arrays of bow-tie gold antennae. The theoretical analysis focuses on the thermal properties and the damage threshold of the bow-tie antennae. On the experimental side the number of contributing atoms is determined and optimized. Extreme ultraviolet radiation is successfully observed with photon fluxes almost an order of magnitude larger than previously reported. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. A Novel Miniaturized Dual Slant-Polarized UWB Antenna Array with Excellent Pattern Symmetry Property for MIMO Applications

    Directory of Open Access Journals (Sweden)

    Zhi Zeng

    2015-01-01

    Full Text Available A novel miniaturized 1 × 10 uniform linear dual slant-polarized UWB antenna array for MIMO base station is presented. The antenna array operates in the frequency band from 1710 to 2690 MHz with a 17.3–18.7 dBi gain in a size of 105 × 1100 × 37 mm. The array element is composed of two single-polarized dipoles evolved from bow-tie antenna with slots on them, which miniaturize the size of the antenna. The 10 array elements are fed through an air dielectric strip-line power splitter. Two parameters, the beam tracking and the beam squint, are presented to quantitatively describe the pattern symmetry property of the antenna. The simulated and measured radiation performances are studied and compared. The results show that the pattern symmetry property of the single antenna element has been improved about 24% compared with the former study, and the antenna array also provides excellent pattern symmetry property.

  10. Electrical Switching of Terahertz Radiation on Vanadium Dioxide Thin Film Fabricated with Nano Antennas

    Science.gov (United States)

    Jeong, Y. G.; Bernien, H.; Kyoung, J. S.; Kim, H. S.; Park, H. R.; Kim, B. J.; Kim, T.; Kim, D. S.

    2011-12-01

    Electrical switching of terahertz radiation through nano antennas on VO2 thin film is demonstrated and is compared with bare VO2. Rectangular apertures act as slot antennas which attract terahertz radiation when VO2 is in semi-conducting state. These antennas are turned-off when VO2 becomes metallic by bias, giving an enhanced control of transmission.

  11. Vector space representation of array antenna pattern synthesis problems

    DEFF Research Database (Denmark)

    Wu, Jian; Roederer, A.G

    1991-01-01

    Considering the difficulties of the nonlinear optimization methods for the array and array fed reflector antenna power pattern synthesis problems, a novel approach has been developed to present the problem in a geographical way, which makes it possible to derive efficient algorithms and to...... visualize the optimization process. The vector space approach described provides a very powerful representation of the array pattern synthesis problems. It is not only general, since many parameters are represented under one model, but also helps to visualize the problem. The proposed approach provides a...

  12. Analysis of Robustness for Convex Optimization Applied to Array Antenna Pattern Synthesis

    Directory of Open Access Journals (Sweden)

    R. Torrealba

    2008-01-01

    Full Text Available This study presents an analysis of the convex optimization applied to the synthesis of the radiation pattern for linear antenna arrays. This study emphasizes the application of the convex optimization for the array pattern synthesis considering the simultaneous elimination of several zones interferences, reduction of the level of power in two space zones densely populated by interferences, as well as the variation of these zones in terms of proximity-distance of the source of interest, variation of the size of the interferences zones and the number of zones within the radiation pattern. Simulation results are provided. These results define certain levels where the linear array could be exploited to achieve a maximum performance.

  13. Development of Radio Frequency Antenna Radiation Simulation Software

    International Nuclear Information System (INIS)

    Antennas are widely used national wide for radio frequency propagation especially for communication system. Radio frequency is electromagnetic spectrum from 10 kHz to 300 GHz and non-ionizing. These radiation exposures to human being have radiation hazard risk. This software was under development using LabVIEW for radio frequency exposure calculation. For the first phase of this development, software purposely to calculate possible maximum exposure for quick base station assessment, using prediction methods. This software also can be used for educational purpose. Some results of this software are comparing with commercial IXUS and free ware NEC software. (author)

  14. Improved patch antenna performance by using a metamaterial cover

    Institute of Scientific and Technical Information of China (English)

    ZHU Fang-ming; HU Jun

    2007-01-01

    A new patch antenna system with a metamaterial cover is presented in this paper. The impedance, radiation pattern, and directivity of such an antenna are studied. A performance comparison between the conventional patch antenna and the new metamaterial patch antenna is given. The results show that the directivity of the metamaterial patch antenna is significantly improved. The effect of the metamaterial cover's layer numbers on the radiation pattern of the patch antenna is also studied.

  15. Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave Antennas

    OpenAIRE

    S Gupta; Jiang, L.; C. Caloz

    2013-01-01

    The radiation principle of travelling-wave type phase-reversal antennas is explained in details, unveiling the presence of magnetic-dipole radiation in addition to well-known electric dipole radiation. It is point out that such magnetic dipole radiation is specific to the case of traveling-wave phase-reversal antennas whereas only electric-dipole radiation exists in resonant-type phase-reversal antennas. It is shown that a phase-reversal travelling-wave antenna alternately operates as an arra...

  16. Color coherence in a heavy quark antenna radiating gluons inside a QCD medium

    International Nuclear Information System (INIS)

    We compute the color coherence effects for soft gluon radiation off antennas containing heavy quarks in the presence of a QCD medium – the actual calculations is made for a triplet configuration and then generalize to both color singlet and octet ones. This work completes the studies of antenna radiation inside a medium which provide a useful picture of the relevance of interference effects in jet parton showers for the jet quenching phenomenon observed in high-energy nuclear collisions. The analysis is performed resumming the multiple scatterings of the partonic system with the medium. The main conclusion is that decorrelation due to color rotation is more effective in the case in which at least one of the emitters of the antenna is a heavy quark. This effect, present both for a heavy-quark–antiquark or a heavy-quark–gluon antenna is more relevant for the later or for the case in which the energies of the quark and antiquark are very different. The parameter controlling these effects involves the dead-cone angle. We find that interferences are cancelled, spoiling the color correlation of the pair, when θDC≡M/E≫1/√(ωL) where E and ω are the energies of the heavy quark and the radiated gluon and L is the medium length. In the case of a heavy-quark–antiquark antenna tform, defined as the difference in splitting times in amplitude and complex conjugate of the amplitude, appears instead of L if the original splitting is symmetric. The presence or absence of interferences modifies the energy loss pattern

  17. A modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    Measurement of radiation efficiency for ultra small antennas represents a great challenge due to influence of the feeding cable. The Wheeler cap method is often used to measure the radiation efficiency of small antennas. However, it is well applicable for antennas on a ground plane......, but not for balanced antennas like loops or dipoles. In this paper, a modified Wheeler cap method is proposed for the radiation efficiency measurement of balanced electrically small antennas and a three-port network model of the Wheeler cap measurement is introduced. The advantage of the modified method...... is that it is wideband, thus does not require any balun, and both the antenna input impedance and radiation efficiency can be obtained. An electrically small loop antenna and a wideband dipole were simulated and measured according to the proposed method and the results of measurements and simulations are presented...

  18. Finite-element-analysis of fields radiated from ICRF antenna

    International Nuclear Information System (INIS)

    In several simple geometries, electromagnetic fields radiated from a loop antenna, on which a current oscillately flows across the static magnetic field B-vector 0, are calculated by the finite element method (FEM) as well as by analytic methods in a cross section of a plasma cylinder. A finite wave number along B-vector 0 is assumed. Good agreement between FEM and the analytic solutions is obtained, which indicates the accuracy of FEM solutions. The method is applied to calculations of fields from a half-turn antenna and reasonable results are obtained. It is found that a straightforward application of FEM to problems in an anisotropic medium may bring about erroneous results and that an appropriate coordinate transformation is needed for FEM to become applicable. (author)

  19. Circular antenna array pattern analysis using radial basis function neural network

    International Nuclear Information System (INIS)

    A method is proposed to design circular antenna array for the given gain and beam width using Artificial Neural Networks. In optimizing circular arrays, the parameters to be controlled are excitation of the elements, their separation, lengths and the circle radius. This paper deals about finding the parameters of radiation pattern of given uniform circular antenna array. Initially, the network is trained with a set of input-output data pairs. The trained network is used for testing. The training data set is generated from MATLAB simulation with number of elements N=5, 10, 15 and 20 elements of uniform circular array, respectively, distributed over a given circle, assuming 20 training cases. The number of input nodes, hidden nodes and output nodes are 20, 20 and 1, respectively. Predicted values of the neural network are compared with those of MATLAB simulation results and are found to be in agreement. This work establishes the application of Radial Basis Function Neural Network (RBFNN) for circular array pattern optimization. RBFNN is able to predict the output values with 97% of accuracy. This work proves that RBFNN can be used for circular antenna array design.

  20. Estimation of radiation characteristics of circular microstrip antenna in weakly ionized plasma medium

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mukesh [B. R. A. Bihar University, Muzaffarpur (India); Kumar, Manoj [Madnani Gali Mithanpura, Muzaffarpur (India); Kumar, Pramod, E-mail: mukbihar@rediffmail.co [Sainik School, Rajgir, Nalanda (India)

    2010-02-01

    The paper deals with the analysis of circular microstrip antenna in weakly ionized plasma medium using the concept of vector magnetic potential, the expression for electric field and magnetic field has been obtained. Attempt has also been made to obtain the radiation resistance, trans-conductance and power radiated from the antenna. Particular emphasis has been given to estimate the effects of weakly ionized plasma medium on the directivity of antenna. It has been found that radiation characteristics and directivity of antenna affected sincerely by the weakly ionized plasma medium.

  1. Improved Pattern Stability for Monopole Antennas with Ultrawideband Impedance Characteristics

    OpenAIRE

    Ammann, Max

    2003-01-01

    The requirement of future software defined and reconfigurable radio networks to operate in multiple, wide-ranging, frequency bands places heavy demands on antenna designs. Rather than using antennas tuned at the time of manufacture to operate in certain predefined frequency bands under predefined radio systems, which limits the possibilities of implementing new radio systems on a reconfigurable terminal, a wideband antenna is proposed. The use of a single antenna which can operate over many o...

  2. MLS airborne antenna research

    Science.gov (United States)

    Yu, C. L.; Burnside, W. D.

    1975-01-01

    The geometrical theory of diffraction was used to analyze the elevation plane pattern of on-aircraft antennas. The radiation patterns for basic elements (infinitesimal dipole, circumferential and axial slot) mounted on fuselage of various aircrafts with or without radome included were calculated and compared well with experimental results. Error phase plots were also presented. The effects of radiation patterns and error phase plots on the polarization selection for the MLS airborne antenna are discussed.

  3. A COMBINED FULL-WAVE BCG-FFT METHOD FOR RADIATION OF MICROSTRIP ANTENNA ARRAYS

    Institute of Scientific and Technical Information of China (English)

    Zhang Hou; Peng Hongli; Liu Qizhong; Yin Yingzeng; Gong Shuxi

    2001-01-01

    A method of combining BiConjugate Gradient(BCG) with Fast Fourier Transform(FFT) to analyze the radiation of microstrip antenna arrays is presented, where the spatially discrete BCG-FFT for analyzing microstrip structure is used and the del operators on Green's functions are transferred from the singular kernel to the expansion and testing functions. The resultant equations are solved by using BCG method in which the matrix-vector product is evaluated efficiently with FFT. The calculated patterns are in good agreement with the measured data.

  4. Terahertz Radiation from Large Aperture Bulk Semi-insulating GaAs Photoconductive Dipole Antenna

    Institute of Scientific and Technical Information of China (English)

    施卫; 贾婉丽; 侯磊; 许景周; 张希成

    2004-01-01

    We report the experimental results of a large-aperture biased semi-insulating GaAs photoconductive dipole antenna, with a gap of 3mm between two Au/Ge/Ni electrodes, triggered by 800nm Ti-sapphire laser pulses with 82 MHz repetition rate. A direct comparison is made between insulated GaAs dipole antenna with a Si3N4 layer and bare GaAs dipole antenna. Both the current in the antenna and the radiation amplitude present as linear to the exciting power when the applied voltage is fixed. The Si3N4 insulated GaAs dipole antenna can hold higher biased voltage than a normal GaAs dipole antenna; its terahertz radiation generation efficiency is significantly higher than that of a normal GaAs dipole antenna.

  5. Slot Antenna Coupled Thin-Film Warm Carrier Far-Infrared Radiation Detectors

    Science.gov (United States)

    Yasuoka, Yoshizumi; Suzuki, Kenji

    Slot antenna coupled thin-film warm carrier devices were fabricated, and the detection properties were investigated at 94 and 700 GHz. Two-dimensional 8 × 3 slot antenna arrays fed by a coplanar waveguide were used as the antennas. The thin-film antennas were fabricated with a photolithographic method, and the warm carrier detectors, which have the contact area of 8 × 10-10 cm2, were fabricated with an electron beam lithographic method. The experimental results indicate that the fabricated devices receive the far-infrared radiation with antenna and rectified it with non-linear I-V characteristic. By changing the antenna from the single slot antenna to the two-dimensional 8 × 3 slot antenna array, the detected sensitivity improved by 11 dB.

  6. Pattern Synthesis of Planar Nonuniform Circular Antenna Arrays Using a Chaotic Adaptive Invasive Weed Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Huaning Wu

    2014-01-01

    Full Text Available A novel invasive weed optimization (IWO variant called chaotic adaptive invasive weed optimization (CAIWO is proposed and applied for the optimization of nonuniform circular antenna arrays. A chaotic search method has been combined into the modified IWO with adaptive dispersion, where the seeds produced by a weed are dispersed in the search space with standard deviation specified by the fitness value of the weed. To evaluate the performance of CAIWO, several representative benchmark functions are minimized using various optimization algorithms. Numerical results demonstrate that the proposed approach improves the performance of the algorithm significantly, in terms of both the convergence speed and exploration ability. Moreover, the scheme of CAIWO is employed to find out an optimal set of weights and antenna element separation to obtain a radiation pattern with maximum side-lobe level (SLL reduction with different numbers of antenna element under two cases with different purposes. The design results obtained by CAIWO have comfortably outperformed the published results obtained by other state-of-the-art metaheuristics in a statistically meaningful way.

  7. Radiation from communication antenna and electrical cable generator

    International Nuclear Information System (INIS)

    Lack of knowledge about radio frequency wave antenna emitter and electrical cable cause misunderstanding among public that make this technologies dangerous, thereby can harm the public hearths. Malaysian Nuclear Agency as one technical body in Malaysia that specialized in this matter had already explained it to the public about this issue long time ago. Basically, non-ionizing radiation are one of the electromagnetic radiation that can be produced naturally or artificially. It consists of two main component, electrical field and magnetic field that propagated with velocity of light. Energy for this radiation less than 12.4 eV, wave distance more than 100 nm with frequency less than 3000 THz. With low energy, this radiation cannot go to ionizing process. Exposure to this radiation also can cause biological effect, acute and chronic. For human that expose to this radiation, direct effect only involved in thermal effect which suddenly increasing of temperature in body. This can cause heat stress, heat stroke and cataract in eyes lens. For infrared, visible light, ultraviolet and laser, the critical organ are eyes and skins. In Malaysia, Telecommunication Department had already produce guideline , Regulatory Framework on the sharing communication infrastructures 1988 that mentioned about all the guideline that must be obey by all the network operator including safety aspect, especially for radio wave and micro wave with frequency from 30 MHz to 300 GHz. The other agencies that produced standards such as SIRIM specialized in level of exposure for electromagnetic radiation until 3 kHz. For the other non-ionizing radiation, guideline from ICNIRP, WHO or others will be referred. For the public the main problem for this issues are psychology problem, political influence and jealously. For Malaysian Nuclear Agency, public awareness must be proceeded in order to give knowledge and understanding about this matter so that the public will not fear in the future.

  8. Omnidirectional Dual-Reflector Antenna with GO Shaped Main Reflector for Pattern Control in the Elevation Plane: OADC Case

    Directory of Open Access Journals (Sweden)

    José R. Bergmann

    2012-01-01

    Full Text Available This paper presents a formulation for shaping the main reflector of an axis-symmetric dual-reflector antenna designed to offer an omnidirectional coverage with an arbitrary radiation pattern in the vertical plane. The subreflector is generated by an axis-displaced conic, and the main reflector is shaped to achieve a prescribed far-field radiation pattern. The procedure is based on geometrical optics (GO principles. Two distinct far-field ray structures are explored and their limitations are identified. The GO shaping results are validated by analysis provided by the accurate method of moments technique.

  9. Miniaturized Dielectric Resonator Antenna with Broadside Radiations for Ultra-Wideband Applications

    Directory of Open Access Journals (Sweden)

    M. Krishna Kumar

    2014-03-01

    Full Text Available This work carries a novel miniaturized Dielectric Resonator Antenna (DRA that has radiations in the broadside region. The antenna was designed and simulated using Advanced Design System (ADS software. The antenna proposed consists of a solid ‘A’ shaped dielectric resonator mounted on the edge of the ground plane to reduce the overall volume and excited by using a microstrip feed line. An air gap is introduced between the resonator and the ground plane inorder to improve the bandwidth. This antenna showed a high efficiency & gain over the proposed radiating frequency. Experimental results show that the antenna radiates at a frequency of 8.9 GHz with a return loss of -19.93 dB. This antenna can also be used alongside with portable wireless devices.

  10. LTE Radiated Data Throughput Measurements, Adopting MIMO 2x2 Reference Antennas

    DEFF Research Database (Denmark)

    Szini, Istvan Janos; Pedersen, Gert Frølund; Barrio, Samantha Caporal Del;

    2012-01-01

    Long Term Evolution (LTE) requires Multiple Input Multiple Output (MIMO) antenna systems. Consequently a new over-the-air (OTA) test methodology need to be created to make proper assessment of LTE devices radiated performance. The antenna specific parameters i.e. total antenna efficiency, gain...... imbalance and correlation coefficient, are essential for a proper MIMO antenna system design. However it can't be use directly to assess the LTE device system performance, since a multiplicity of other factors are involved, e.g. power amplifier load- pull, low noise amplifier source-pull, self interference...... performance, ruling out the LTE devices unknown MIMO 2x2 antenna performance....

  11. Analytical form of EM fields radiated by circular aperture antennas of various current distributions

    Institute of Scientific and Technical Information of China (English)

    Le-Wei Li; Qun Wu

    2005-01-01

    In this paper, the electromagnetic radiation by circular aperture antennas fed by circular waveguides is considered. Electromagnetic fields radiated by the aperture antennas are formulated in detail and two aperture field distributions are considered, one being the uniform distribution and the other being the TE11-mode distribution. Some mistakes existing in the literature are pointed out. The detailed derivations for the fields by the TE11-mode distribution aperture were not commonly available in the public literature, although the solution is available. The analytical results obtained here are useful for antenna designers and antenna engineering education.

  12. Antennas - Our electronic eyes and ears

    Science.gov (United States)

    Kraus, John D.

    1989-01-01

    Although the number of antenna types is vast, all antenna properties may be characterized in terms of the same basic parameters of radiation pattern, impedance, radar cross-section, and temperature. A comprehensive introduction is presented to antenna configurations; these encompass, among antennas constructed of wire or tubing, such wideband and circularly polarized types as helices, linear conductors, and loops. Sheet-conductor antenna families include reflectors, waveguides, and slotted antennas. Nonconducting dielectric antennas are lenses, polyrods, and slabs. Antenna array types range over 'driven', parasitic, and adaptive configurations. 'Two half-wavelength' and 'four half-wavelength' element arrays are also discussed.

  13. Method of measuring the amplitude directivity pattern of parabolic mirrored antennas in the audio frequency range

    Directory of Open Access Journals (Sweden)

    Sadchenko A. V.

    2016-02-01

    Full Text Available Directivity pattern (DP or graphical representation of the dependence of gain factor (directivity gain of antennas on the direction of the antenna in the target plane is the main characteristic that describes its directional properties. Running DP measurements directly in the microwave range is very expensive. While generating and receiving devices for the acoustic frequency range are reasonably priced. In this paper, we propose a method for measuring the amplitude directivity pattern of parabolic mirrored antennas on the basis of sound equivalent, which is based on the identity of the numerical values of the directivity gain of microwave range, and at audio frequencies. The paper presents analytical expressions for the calculation of equivalent frequency and defines the requirements for the minimum size of the antenna. The paper contains a modified block diagram for an amplitude directivity pattern meter for parabolic mirrored antennas in the audio frequency range.

  14. The compact linear antenna array system of the short-wave band consisting of "butterfly" radiators

    OpenAIRE

    Kudzin, Viktor P.; Lozovsky, V. N.; N.I. Shlyk

    2014-01-01

    The broadband linear antenna array system of vertical polarization for a short-wave band operation consisting of "butterfly" radiators is offered. Antenna system consists of two arrays located before each other. Array 1 operates in frequency band 4–8 MHz, array 2 – in band 8–16 MHz. Wire reflector serves for array 1 and the last serves as reflector for array 2. Advantage of antenna system is "planeness" of a design and absence of high-frequency insulators.

  15. Including Arbitrary Antenna Patterns in Microwave Imaging of Buried Objects

    DEFF Research Database (Denmark)

    Meincke, Peter; Kim, Oleksiy S.; Lenler-Eriksen, Hans-Rudolph

    2004-01-01

    A linear inversion scheme for microwave imaging of buried objects is presented in which arbitrary antennas are accounted for through their plane-wave transmitting and receiving spectra......A linear inversion scheme for microwave imaging of buried objects is presented in which arbitrary antennas are accounted for through their plane-wave transmitting and receiving spectra...

  16. Magnetic antenna excitation of whistler modes. IV. Receiving antennas and reciprocity

    Energy Technology Data Exchange (ETDEWEB)

    Stenzel, R. L., E-mail: stenzel@physics.ucla.edu; Urrutia, J. M. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095-1547 (United States)

    2015-07-15

    Antenna radiation patterns are an important property of antennas. Reciprocity holds in free space and the radiation patterns for exciting and receiving antennas are the same. In anisotropic plasmas, radiation patterns are complicated by the fact that group and phase velocities differ and certain wave properties like helicity depend on the direction of wave propagation with respect to the background magnetic field B{sub 0}. Interference and wave focusing effects are different than in free space. Reciprocity does not necessarily hold in a magnetized plasma. The present work considers the properties of various magnetic antennas used for receiving whistler modes. It is based on experimental data from exciting low frequency whistler modes in a large uniform laboratory plasma. By superposition of linear waves from different antennas, the radiation patterns of antenna arrays are derived. Plane waves are generated and used to determine receiving radiation patterns of different receiving antennas. Antenna arrays have radiation patterns with narrow lobes, whose angular position can be varied by physical rotation or electronic phase shifting. Reciprocity applies to broadside antenna arrays but not to end fire arrays which can have asymmetric lobes with respect to B{sub 0}. The effect of a relative motion between an antenna and the plasma has been modeled by the propagation of a short wave packet moving along a linear antenna array. An antenna moving across B{sub 0} has a radiation pattern characterized by an oscillatory “whistler wing.” A receiving antenna in motion can detect any plane wave within the group velocity resonance cone. The radiation pattern also depends on loop size relative to the wavelength. Motional effects prevent reciprocity. The concept of the radiation pattern loses its significance for wave packets since the received signal does not only depend on the antenna but also on the properties of the wave packet. The present results are of fundamental

  17. A Study of Near-Field Radiation Pattern of Bow-Tie Dipole on Ground

    Institute of Scientific and Technical Information of China (English)

    ZHAN Yi; LIANG Changhong; FANG Guangyou; YUAN Hongwei

    2001-01-01

    The study of bow-tie antenna forpulse'radiation in a ground penetrating radar systemis complicated due to the existence of reflections fromthe feed,the far end of the antenna,the air-groundinterface and their interactions.The FDTD methodsare applied in this paper by incorporating a trans-parent source,a bow-tie antenna above the ground,and a lossy soil to investigate the issues.Numeri-cal verifications are conducted to check the accuracyof the method.The radiation properties are demon-strated by near-field radiation patterns and time do-main waveforms at different positions.The influencesdue to different antenna heights and soil parametersare also discussed in detail.

  18. Lower Bound for the Radiation $Q$ of Electrically Small Magnetic Dipole Antennas With Solid Magnetodielectric Core

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2011-01-01

    A new lower bound for the radiation $Q$ of electrically small spherical magnetic dipole antennas with solid magnetodielectric core is derived in closed form using the exact theory. The new bound approaches the Chu lower bound from above as the antenna electrical size decreases. For $ka, the new b...

  19. Decreasing the radiation quality factor of magnetic dipole antennas by a magnetic-coated metal core

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2010-01-01

    To achieve the Chu lower bound for the radiation Q, an electrically small magnetic dipole antenna should not store any magnetic energy internally to the minimum sphere enclosing the antenna. As shown in our previous works, the internal stored magnetic energy can be reduced, although not entirely...

  20. Evaluation of the Radiation Efficiency and the Noise Temperature of Low-Loss Antennas

    NARCIS (Netherlands)

    Maaskant, R.; Bekers, D.J.; Arts, M.J.; Cappellen, W.A. van; Ivashina, M.V.

    2009-01-01

    An accurate evaluation of the noise temperature of noncooled antenna systems is of great importance, particularly if the specifications of the antenna alone are a fewKelvins as in applications for radio astronomy. This evaluation requires an accurate analysis of the radiation efficiency, which we ev

  1. Antenna structure with distributed strip

    Science.gov (United States)

    Rodenbeck, Christopher T.

    2008-03-18

    An antenna comprises electrical conductors arranged to form a radiating element including a folded line configuration and a distributed strip configuration, where the radiating element is in proximity to a ground conductor. The folded line and the distributed strip can be electrically interconnected and substantially coplanar. The ground conductor can be spaced from, and coplanar to, the radiating element, or can alternatively lie in a plane set at an angle to the radiating element. Embodiments of the antenna include conductor patterns formed on a printed wiring board, having a ground plane, spacedly adjacent to and coplanar with the radiating element. Other embodiments of the antenna comprise a ground plane and radiating element on opposed sides of a printed wiring board. Other embodiments of the antenna comprise conductors that can be arranged as free standing "foils". Other embodiments include antennas that are encapsulated into a package containing the antenna.

  2. Controlling spontaneous emission with plasmonic optical patch antennas

    OpenAIRE

    Belacel, C.; Habert, B.; Bigourdan, F.; Marquier, F.; Hugonin, J.-P.; Michaelis de Vasconcellos, S.; Lafosse, X.; Coolen, L; Schwob, C.; Javaux, C; Dubertret, B.; Greffet, J. -J.; Senellart, P.; Maitre, A.

    2012-01-01

    We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk 30 nm above a thick gold layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending of the antenna size. Considering the double...

  3. Modelling the Impact of Ground Planes on Antenna Radiation Using the Method of Auxiliary Sources

    DEFF Research Database (Denmark)

    Larsen, Niels Vesterdal; Breinbjerg, Olav

    2007-01-01

    The Method of Auxiliary Sources is employed to model the impact of finite ground planes on the radiation from antennas. In many cases the computational cost of available commercial tools restricts the simulations to include only a small ground plane or, by use of the image principle, the infinitely...... simulation results for the case of crossed Hertzian dipoles antennas. Later the method is applied to the cases of real antennas, a slot antenna and a printed dipole phased array, for which corresponding measurements have been conducted. The results obtained with the method agree well with the simulated...

  4. Very high-accuracy calibration of radiation pattern and gain of a near-field probe

    DEFF Research Database (Denmark)

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

    2014-01-01

    In this paper, very high-accuracy calibration of the radiation pattern and gain of a near-field probe is described. An open-ended waveguide near-field probe has been used in a recent measurement of the C-band Synthetic Aperture Radar (SAR) Antenna Subsystem for the Sentinel 1 mission of the Europ......In this paper, very high-accuracy calibration of the radiation pattern and gain of a near-field probe is described. An open-ended waveguide near-field probe has been used in a recent measurement of the C-band Synthetic Aperture Radar (SAR) Antenna Subsystem for the Sentinel 1 mission...

  5. A novel quadrifilar helix antenna for use in LEO satellite communications

    OpenAIRE

    Mirkamali, Ali; Akhoondzadeh, Lida; Keyghobad, Kiyan; Soleimani, Mohammad

    2003-01-01

    A spherical quadrifilar helix antenna (SQHA) is introduced for producing a saddle point shaped radiation pattern. Radiation characteristics of the antenna have been simulated and the results have been compared with the characteristics of the cylindrical quadrifilar helix antenna (CQHA) which was previously used for this purpose. The results show an improvement in radiation pattern of the proposed antenna in comparison with the previous antenna.

  6. Mass effect and coherence in medium-induced QCD radiation off a $q {\\bar q}$ antenna

    CERN Document Server

    Armesto, Néstor; Mehtar-Tani, Yacine; Salgado, Carlos A; Tywoniuk, Konrad

    2011-01-01

    The medium-induced one-gluon radiation spectrum off a massive quark-antiquark ($q {\\bar q}$) antenna traversing a colored QCD medium is calculated in this contribution. The gluon spectrum off the antenna computed at first order in the opacity expansion is collinear finite but infrared divergent, which is different from the result obtained from an independent emitter which is both infrared and collinear finite. The interference between emitters dominates the soft gluon radiation when the antenna opening angle is small and the emitted gluon is soft, whereas the antenna behaves like a superposition of independent emitters when the opening angle is large and the radiated gluon is hard. As a phenomenological consequence, we investigate the energy lost by the projectiles due to the radiation. In general, the size of the mass effects is similar in both cases.

  7. Thermal radiation antennas made of multilayer structures containing negative index metamaterials

    NARCIS (Netherlands)

    Maksimovic, M.; Hammer, M.; Jaksic, Z.; Greiner, C.M.; Waechter, C.A.

    2008-01-01

    We investigate the thermal antenna behavior of emissive/absorptive substrates coated by passive optical multilayer systems that contain negative refractive index metamaterials (NIM). Spectral and angular distributions of the thermal radiation emittance for periodic defect-containing multilayer with

  8. A COMPACT CIRCULARLY POLARIZED SLOTTED MICROSTRIP ANTENNA

    OpenAIRE

    V. Jebaraj; K.R.S. Ravi Kumar; D. Mohanageetha

    2014-01-01

    Slot antennas are often used at UHF and microwave frequencies. In slot antenna for RFID reader applications the frequency ranges from 902-923MHz to achieve circular polarization. The shapes and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. The proposed compact size circularly polarized slotted microstrip antenna are summarized with design rules. The circularly polarized radiation in square patch antenna can be obtained by perturbation techni...

  9. A novel coaxial CTS antenna design

    OpenAIRE

    Qiu, Jinghui; Xing, Xiaohang; Ling-Ling, Zhong

    2007-01-01

    CTS (Continuous Transverse Stub) antenna radiates electromagnetic wave with its transverse stubs on transmission line, and its pattern in horizon plane is omnidirectional. This paper proposes a novel coaxial CTS structure, in which a monopole is applied in coaxial CTS antenna, instead of a matching load. This method may not only improve the radiation ratio, but also reduce the height of antenna. There are two stubs and a monopole composing an antenna, and the dielectric in stubs is air, which...

  10. Electric Dipole Antenna: A Source of Gravitational Radiation

    Directory of Open Access Journals (Sweden)

    Chifu E. N.

    2013-07-01

    Full Text Available In this article, the gravitational scalar potential due to an oscillating electric dipole antenna placed in empty space is derived. The gravitational potential obtained propagates as a wave. The gravitational waves have phase velocity equal to the speed of light in vacuum (c at the equatorial plane of the electric dipole antenna, unlike electromagnetic waves from the dipole antenna that cancel out at the equatorial plane due to charge symmetry.

  11. Single Band Helical Antenna in Axial Mode

    Directory of Open Access Journals (Sweden)

    Parminder Singh

    2012-11-01

    Full Text Available Helical antennas have been widely used in a various useful applications, due to their low weight and low profile conformability, easy and cheap realization.Radiation properties of this antenna are examined both theoretically and experimentally. In this paper, an attempt has been made to investigate new helical antenna structure for Applications. CST MWS Software is used for the simulation and design calculations of the helical antennas. The axial ratio, return loss, VSWR, Directivity, gain, radiation pattern is evaluated. Using CST MWS simulation software proposed antenna is designed/simulated and optimized. The antenna exhibits a single band from 0 GHz to 3 GHz for GPS and several satellite applications

  12. Radiation Field of a Square, Helical Beam Antenna

    DEFF Research Database (Denmark)

    Knudsen, Hans Lottrup

    1952-01-01

    square helices are used. Further, in connection with corresponding rigorous formulas for the field from a circular, helical antenna with a uniformly progressing current wave of constant amplitude the present formulas may be used for an investigation of the magnitude of the error introduced in Kraus......' approximate calculation of the field from a circular, helical antenna by replacing this antenna with an ``equivalent'' square helix. This investigation is carried out by means of a numerical example. The investigation shows that Kraus' approximate method of calculation yields results in fair agreement......Rigorous formulas have been derived for the field from a square, helical antenna with a uniformly progressing current wave of constant amplitude. These formulas that have the advantage of great simplicity are of direct use for helical antennas in the meter band, where for practical reasons only...

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

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.

    1994-01-01

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

  14. Antenna arrays. Citations from the NTIS data base

    Science.gov (United States)

    Reed, W. E.

    1980-04-01

    A bibliography containing 161 abstracts concerning the use of antenna arrays in the fields of radar, communications, radio astronomy, navigation, electronic countermeasures, and spacecraft is presented. Topics include design, antenna radiation patterns, mathematical models, and performance.

  15. Plasma antennas: dynamically configurable antennas for communications

    International Nuclear Information System (INIS)

    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

  16. Enhancing and redirecting carbon nanotube photoluminescence by an optical antenna

    OpenAIRE

    Böhmler, Miriam; Hartmann, Nicolai; Georgi, Carsten; Hennrich, Frank; Green, Alexander A.; Hersam, Mark C.; Hartschuh, Achim

    2010-01-01

    We observe the angular radiation pattern of single carbon nanotubes' photoluminescence in the back focal plane of a microscope objective and show that the emitting nanotube can be described by a single in-plane point dipole. The near-field interaction between a nanotube and an optical antenna modifies the radiation pattern that is now dominated by the antenna characteristics. We quantify the antenna induced excitation and radiation enhancement and show that the radiative rate enhancement is c...

  17. Compact reflector antenna with the monopole sub-reflector

    OpenAIRE

    Radionov, S. A.

    2007-01-01

    This paper is devoted to designing and manufacturing the compact wideband reflector antenna with the monopole sub-reflector. Based on the computation modeling and experimental investigations the effect of separate elements of the proposed antenna on the radiation characteristics is studied. The regularities of radiation pattern shape are determined. Finally, the experimental antenna prototype is described, as well as the input antenna characteristics, near-field distributions and radiation pa...

  18. A Method for Measuring the Radiation Pattern of UHF RFID Transponders

    Directory of Open Access Journals (Sweden)

    Jankowski-Mihułowicz Piotr

    2016-06-01

    Full Text Available The operating principles of RFID antennas should be considered differently than it is applied in the classical theory of radio communication systems. The procedure of measuring the radiation pattern of antennas that could be applied to RFID transponders operating in the UHF band is seldom discussed correctly in the scientific literature. The problem consists in the variability of the RFID chip impedance that strongly influences measurement results. The authors propose the proper methodology for determining the radiation pattern with respect to an individual transponder as well as an electronically tagged object. The advantage of the solution consists in the possibility of using components of different measuring systems that are available in typical antenna laboratories. The proposed procedure is particularly important in terms of parameter validation - the identification efficiency and costs of an RFID system implementation can be evaluated properly only on the basis of real values of considered parameters.

  19. Near field of corrugated horns and its influence on dual reflector antenna radiation performance

    Science.gov (United States)

    Hombach, V.; Kuehn, E.

    1985-05-01

    The existing procedures for calculating the near field of the corrugated horns of dual reflector antennas are briefly reviewed, and their disadvantages are pointed out. A new approach to calculating the near field of circular corrugated feed horns is then discussed with specific reference to a Ku-band offset Gregorian antenna developed for the German Telecommunication Satellite DFS scheduled for launch in 1987. The approach, which is based on a physical-optics solution, is shown to provide an accurate description of the actual radiation characteristics. The effect of the near field on the gain, side-lobe level, and cross-polar performance of the antenna is discussed.

  20. Characteristics of block-periodic phased-array antennas with circular polarization of the radiated field

    Science.gov (United States)

    Likhoded, Iu. V.; Mironnikov, A. S.

    1990-02-01

    The paper presents results of a numerical investigation of the directivity characteristics of a block-periodic waveguide phased-array antenna with circular polarization of the radiated field. The advantages of this array from the viewpoint of maximining the ellipticity coefficent of the radiated field in the scanning sector are pointed out.

  1. Bow-tie nano-antenna assisted generation of extreme ultraviolet radiation

    OpenAIRE

    Pfullmann, N.; Waltermann, C.; Noack, M.; Rausch, S.; Nagy, T.; Reinhardt, C.; Kovacev, M.; Knittel, V.; Bratschitsch, R.; Akemeier, D.; Huetten, A.; Leitenstorfer, A.; Morgner, Uwe

    2013-01-01

    We report on the generation of extreme ultraviolet radiation utilizing the plasmonic field enhancement in arrays of bow-tie gold optical antennae. Furthermore, their suitability to support high-order harmonic generation is examined by means of finite-difference time-domain calculations and experiments. Particular emphasis is paid to the thermal properties, which become significant at the employed peak intensities. A damage threshold depending on the antenna length is predict...

  2. Optimisation of Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    H. El Hamchary

    1996-04-01

    Full Text Available When choosing the most appropriate microstrip antenna configuration for particular applications, the kind of excitation of the radiating element is an essential factor that requires careful considerations. For controlling the distribution of energy of the linear or planar array of elements and for coupling energy to the individual elements, a wide variety of feed mechanisms are available. In this paper, the coaxial antenna feeding is assumed and the best (optimised feeding is found. Then, antenna characteristics such as radiation pattern, return loss, input impedance, and VSWR are obtained.

  3. CPW-Fed Slot Antenna for Wideband Applications

    Directory of Open Access Journals (Sweden)

    T. Shanmuganantham

    2008-01-01

    Full Text Available A new coplanar waveguide (CPW-fed wideband printed slot antenna is presented, and the impedance characteristics of this antenna with different sizes of tapers are discussed. The effect of tapering angle with the resonant frequency is also observed. The fundamental parameters of the antenna such as bandwidth, return loss, gain, radiation pattern, and polarization are obtained. All meets the acceptable antenna standards. The measured input impedance bandwidth (return loss < −10 dB of the prototype antenna is 52% (4.27–7.58 GHz. The radiation patterns are bidirectional in both planes. This antenna can be part of various wireless communication systems.

  4. Generation of high-power electromagnetic radiation by a beam-driven plasma antenna

    Science.gov (United States)

    Annenkov, V. V.; Volchok, E. P.; Timofeev, I. V.

    2016-04-01

    In this paper we study how efficiently electromagnetic radiation can be generated by a relativistic electron beam with a gigawatt power level during its injection into a thin magnetized plasma. It is shown that, if the transverse beam and plasma size is compared with the radiation wavelength and the plasma density is modulated along the magnetic field, such a beam-plasma system can radiate electromagnetic waves via the antenna mechanism. We propose a theoretical model describing generation of electromagnetic waves by this plasma antenna and calculate its main radiation characteristics. In the two-dimensional case theoretical predictions on the radiation efficiency are shown to be confirmed by the results of particle-in-cell simulations, and the three-dimensional variant of this theory is used to estimate the peak power of sub-terahertz radiation that can be achieved in beam-plasma experiments in mirror traps.

  5. Antenna-coupled terahertz radiation from joule-heated single-wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    M. Muthee

    2011-12-01

    Full Text Available In this letter an experimental method is introduced that allows detection of terahertz (THz radiation from arrays of joule-heated Single-Walled Carbon Nanotubes (SWCNTs, by coupling this radiation through integrated antennas and a silicon lens. The radiation forms a diffraction-limited beam with a total maximum radiated power of 450 nW, significantly greater than the power estimated from Nyquist thermal noise (8 nW. The physical radiation process is unknown at this stage, but possible explanations for the high radiated power are discussed briefly. The emission has a typical bandwidth of 1.2 THz and can be tuned to different frequencies by changing the dimensions of the antennas. Arrays of the devices could be integrated in CMOS integrated circuits, and find application in THz systems, such as in near-range medical imaging.

  6. TOLPA (Tripod Omnidirectional Low Profile Antenna): a vertically polarized antenna with 90% bandwidth

    OpenAIRE

    Zürcher, J.-F.

    2013-01-01

    A new vertically polarized omnidirectional antenna, inspired by an old design, has been studied, optimized, realized and measured. With a radiation pattern similar to the classical monopole on a ground plane, the proposed antenna concept provides a much larger bandwidth and a very low profile. This antenna has numerous potential applications for mobile communications, UWB and others.

  7. Theory of Optical Leaky-Wave Antenna Integrated in a Ring Resonator for Radiation Control

    CERN Document Server

    Guclu, Caner; Capolino, Filippo

    2015-01-01

    The integration of a leaky-wave antenna with a ring resonator is presented using analytical guided wave models. The device consists of a ring resonator fed by a directional coupler, where the ring resonator path includes a leaky-wave antenna segment. The resonator integration provides two main advantages: the high-quality factor ensures effective control of radiation intensity by controlling the resonance conditions and the efficient radiation from a leaky-wave antenna even when its length is much smaller than the propagation length of the leaky wave. We devise an analytical model of the guided wave propagation along a directional coupler and the ring resonator path including the antenna and non-radiating segments. The trade-offs regarding the quality factor of resonance and the antenna efficiency of such a design is reported in terms of the coupler parameters, leaky-wave constant and radiation length. Finally a CMOS-compatible OLWA design suitable for the ring resonator integration is designed where Silicon ...

  8. Rectangular dielectric resonator antennas theory and design

    CERN Document Server

    Yaduvanshi, Rajveer S

    2016-01-01

    This book covers resonating modes inside device and gives insights into antenna design, impedance and radiation patterns. It discusses how higher-order modes generation and control impact bandwidth and antenna gain. The text covers new approaches in antenna design by investigation hybrid modes, H_Z and E_Z fields available simultaneously, and analysis and modelling on modes with practical applications in antenna design. The book will be prove useful to students, researchers and professionals alike.

  9. Computation of radiation from wire antennas on conducting bodies

    DEFF Research Database (Denmark)

    Albertsen, N. Christian; Hansen, Jesper; Jensen, Niels E.

    1974-01-01

    A theoretical formulation, in terms of combined magnetic and electric field integral equations, is presented for the class of electromagnetic problems in which one or more wire antennas are connected to a conducting body of arbitrary shape. The formulation is suitable for numerical computation...

  10. 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.

  11. Performance Characterization of Radial Stub Microstrip Bow-Tie Antenna

    OpenAIRE

    B.T.P.Madhav; S.S. Mohan Reddy; Neha Sharma; J. Ravindranath Chowdary; Bala Rama Pavithra; K.N.V.S. Kishore; G Sriram; B. Sachin Kumar

    2013-01-01

    In this paper a novel radial stub feeding microstrip bow-tie antenna is designed to operate between C and X band and its performance characterization is presented. This antenna is having simple structure and topology over other stub loaded antennas. In addition the proposed antenna adjusts to the desired frequency easily. Antenna output parameters like radiation pattern, axial ratio, directive gain andquality factor are simulated and presented in this current work.

  12. Performance Characterization of Radial Stub Microstrip Bow-Tie Antenna

    Directory of Open Access Journals (Sweden)

    B.T.P.Madhav

    2013-04-01

    Full Text Available In this paper a novel radial stub feeding microstrip bow-tie antenna is designed to operate between C and X band and its performance characterization is presented. This antenna is having simple structure and topology over other stub loaded antennas. In addition the proposed antenna adjusts to the desired frequency easily. Antenna output parameters like radiation pattern, axial ratio, directive gain andquality factor are simulated and presented in this current work.

  13. Definition of accurate reference pattern for the DTU-ESA VAST12 antenna

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Breinbjerg, Olav; Burgos, Sara;

    2009-01-01

    In this paper, the DTU-ESA 12 GHz validation standard (VAST12) antenna and a dedicated measurement campaign carried out in 2007-2008 for the definition of its accurate reference pattern are first described. Next, a comparison between the results from the three involved measurement facilities is...

  14. Multiobjective Synthesis of Steerable UWB Circular Antenna Array considering Energy Patterns

    Directory of Open Access Journals (Sweden)

    Leopoldo A. Garza

    2015-01-01

    Full Text Available True-time delay antenna arrays have gained a prominent attention in ultrawideband (UWB applications such as directional communications and radar. This paper presents the design of steerable UWB circular array by using a multiobjective time-domain synthesis of energy pattern for circular antenna arrays. By this way we avoid individual beamforming for each frequency in UWB spectrum if the problem was addressed from the frequency domain. In order to obtain an energy pattern with low side lobe level and a desired main beam, the synthesis presented is performed by optimizing the true-time delays and amplitude coefficients for the antenna elements in a circular geometry. The method of Differential Evolution for Multiobjective Optimization (DEMO is used as the optimization algorithm in this work. This design of steerable UWB circular arrays considers the optimization of the true-time exciting delays and the amplitude coefficients across the antenna elements to operate with optimal performance in the whole azimuth plane (360°. A comparative analysis of the performance of the optimized design with the case of conventional progressive delay excitations is achieved. The provided results show a good performance for energy patterns and for their respective power patterns in the UWB spectrum.

  15. Modeling the radiation pattern of LEDs.

    Science.gov (United States)

    Moreno, Ivan; Sun, Ching-Cherng

    2008-02-01

    Light-emitting diodes (LEDs) come in many varieties and with a wide range of radiation patterns. We propose a general, simple but accurate analytic representation for the radiation pattern of the light emitted from an LED. To accurately render both the angular intensity distribution and the irradiance spatial pattern, a simple phenomenological model takes into account the emitting surfaces (chip, chip array, or phosphor surface), and the light redirected by both the reflecting cup and the encapsulating lens. Mathematically, the pattern is described as the sum of a maximum of two or three Gaussian or cosine-power functions. The resulting equation is widely applicable for any kind of LED of practical interest. We accurately model a wide variety of radiation patterns from several world-class manufacturers.

  16. Radiation and scattering from printed antennas on cylindrically conformal platforms

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.; Bindiganavale, Sunil

    1994-01-01

    The goal was to develop suitable methods and software for the analysis of antennas on cylindrical coated and uncoated platforms. Specifically, the finite element boundary integral and finite element ABC methods were employed successfully and associated software were developed for the analysis and design of wraparound and discrete cavity-backed arrays situated on cylindrical platforms. This work led to the successful implementation of analysis software for such antennas. Developments which played a role in this respect are the efficient implementation of the 3D Green's function for a metallic cylinder, the incorporation of the fast Fourier transform in computing the matrix-vector products executed in the solver of the finite element-boundary integral system, and the development of a new absorbing boundary condition for terminating the finite element mesh on cylindrical surfaces.

  17. Radiative properties of diffractively-coupled optical nano-antennas with helical geometry.

    Science.gov (United States)

    Wang, Ren; Forestiere, Carlo; Dal Negro, Luca

    2015-10-01

    In this paper, using the rigorous Surface Integral Equation (SIE) method, we study light scattering by Au nano-helices with geometrical dimensions comparable to the wavelength of visible light and we demonstrate that they behave as highly directional nano-antennas with largely controllable radiation and polarization characteristics in the optical regime. In particular, we systematically investigate the radiation properties of helical nano-antennas with realistic Au dispersion parameters in the visible spectral range, and we establish general design rules that enable the engineering of directional scattering with elliptical or circular polarization. Given the realistic material and geometric parameters used in this work, our findings provide novel opportunities for the engineering of chiral sensors, filters, and components for nano-scale antennas with unprecedented beam forming and polarization capabilities.

  18. Smart antennas

    CERN Document Server

    Godara, Lal Chand

    2004-01-01

    INTRODUCTION Antenna GainPhased Array AntennaPower Pattern Beam Steering Degree of Freedom Optimal AntennaAdaptive AntennaSmart AntennaSummary NARROWBAND PROCESSINGSignal Model Conventional BeamformerNull Steering BeamformerOptimal BeamformerOptimization Using Reference SignalBeam Space Processing Effect of ErrorsNotation and AbbreviationsReferencesADAPTIVE PROCESSINGSample Matrix Inversion AlgorithmUnconstrained Least Mean Squares AlgorithmNormalized Least Mean Squares AlgorithmConstrained

  19. Directional borehole antenna - Theory

    International Nuclear Information System (INIS)

    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)

  20. Antenna reconfiguration using metasurfaces

    OpenAIRE

    Zhu, H; Cheung, WSW; Yuk, TI

    2014-01-01

    The paper describes the designs of a frequency-reconfigurable, polarization reconfigurable and pattern reconfigurable antennas using metasurfaces (MS). The frequency-reconfigurable and polarization reconfigurable antennas are composed of a simple circular patch antenna or slot antenna as the source antenna and a circular MS with the same diameter, with both source antenna and MS implemented using planar technology. The pattern reconfigurable antenna is composed of a circular patch antenna as ...

  1. Localized radiative energy transfer from a plasmonic bow-tie nano-antenna to a magnetic thin film stack

    OpenAIRE

    Sendur, K.; Kosar, A.; Mengüç, M. Pınar

    2011-01-01

    Localized radiative energy transfer from a near-field emitter to a magnetic thin film structure is investigated. A magnetic thin film stack is placed in the near-field of the plasmonic nano-antenna to utilize the evanescent mode coupling between the nano-antenna and magnetic thin film stack. A bow-tie nano-optical antenna is excited with a tightly focused beam of light to improve near-field radiative energy transfer from the antenna to the magnetic thin film structure. A tightly focused incid...

  2. Efficient PO-MOM Method for Analysis of the Radiation Characteristics of a Large Antenna-Radome System

    Institute of Scientific and Technical Information of China (English)

    HU Bing; XU Xiao-wen; HE Mang

    2008-01-01

    An efficient hybrid method based on the method of moments (MOM) and physical optics (PO) for the analysis of radiation characteristics of an electrically large antenna-radome system is presented. Specifically, MOM is first applied to the antenna to find the current on its surface, and then the equivalent PO currents produced by the antenna radiation are assumed on the radome wall. When the coupling of the PO currents and antenna current is considered, the coupling matrix is divided into a series of partial matrices, in order to deduce the memory requirement and accelerate the evaluation process. Numerical results indicate that the proposed hybrid PO-MOM method is accurate and efficient.

  3. The radiation performance of offset reflector antennas with horn feeds excited by high order modes

    Science.gov (United States)

    Thielen, Herbert

    1988-07-01

    The physical reasons for alignment errors in the antenna tracking of asymmetric reflector systems were investigated. The radiation behavior of offset reflector antennas, employing higher-order modes was theoretically and experimentally analyzed. In the case of TE21-mode excitation, a cross-polarization component is produced in single-reflector antennas due to feed tilt which is considerably larger than with the communication mode (TE11 or HE11 mode). In the case of circular polarization, this causes a null shift amounting to 1/10 or 1/5 of the half-power beam width of the main lobe. No null shift exists for the TM01- and TE01-modes. When the TE21-mode is used, the cross-polarization component is considerably smaller for dual-offset than for single-reflector antennas. In the case of ground station antennas where beam-waveguides consisting of two reflectors are used, a similar performance is obtained as for single-reflector antennas.

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  5. Modelling and measurement of the absolute level of power radiated by antenna integrated THz UTC photodiodes.

    Science.gov (United States)

    Natrella, Michele; Liu, Chin-Pang; Graham, Chris; van Dijk, Frederic; Liu, Huiyun; Renaud, Cyril C; Seeds, Alwyn J

    2016-05-30

    We determine the output impedance of uni-travelling carrier (UTC) photodiodes at frequencies up to 400 GHz by performing, for the first time, 3D full-wave modelling of detailed UTC photodiode structures. In addition, we demonstrate the importance of the UTC impedance evaluation, by using it in the prediction of the absolute power radiated by an antenna integrated UTC, over a broad frequency range and confirming the predictions by experimental measurements up to 185 GHz. This is done by means of 3D full-wave modelling and is only possible since the source (UTC) to antenna impedance match is properly taken into account. We also show that, when the UTC-to-antenna coupling efficiency is modelled using the classical junction-capacitance/series-resistance concept, calculated and measured levels of absolute radiated power are in substantial disagreement, and the maximum radiated power is overestimated by a factor of almost 7 dB. The ability to calculate the absolute emitted power correctly enables the radiated power to be maximised through optimisation of the UTC-to-antenna impedance match.

  6. Modelling and measurement of the absolute level of power radiated by antenna integrated THz UTC photodiodes.

    Science.gov (United States)

    Natrella, Michele; Liu, Chin-Pang; Graham, Chris; van Dijk, Frederic; Liu, Huiyun; Renaud, Cyril C; Seeds, Alwyn J

    2016-05-30

    We determine the output impedance of uni-travelling carrier (UTC) photodiodes at frequencies up to 400 GHz by performing, for the first time, 3D full-wave modelling of detailed UTC photodiode structures. In addition, we demonstrate the importance of the UTC impedance evaluation, by using it in the prediction of the absolute power radiated by an antenna integrated UTC, over a broad frequency range and confirming the predictions by experimental measurements up to 185 GHz. This is done by means of 3D full-wave modelling and is only possible since the source (UTC) to antenna impedance match is properly taken into account. We also show that, when the UTC-to-antenna coupling efficiency is modelled using the classical junction-capacitance/series-resistance concept, calculated and measured levels of absolute radiated power are in substantial disagreement, and the maximum radiated power is overestimated by a factor of almost 7 dB. The ability to calculate the absolute emitted power correctly enables the radiated power to be maximised through optimisation of the UTC-to-antenna impedance match. PMID:27410104

  7. On the Optimal Radiation Bandwidth of Printed Slot Antennas Surrounded by EBGs

    NARCIS (Netherlands)

    Neto, A.; Llombart, N.; Gerini, G.; Maagt, P. de

    2006-01-01

    This paper describes a design strategy to achieve the maximum bandwidth and efficiency for a printed slot antenna surrounded by EBGs. First the dielectric constant and the thickness of the dielectric slab that guarantees an acceptable front to back radiation ratio is identified. Then electromagnetic

  8. Multifrequency Printed Antennas Loaded with Metamaterial Particles

    Directory of Open Access Journals (Sweden)

    D. Segovia-Vargas

    2009-06-01

    Full Text Available This paper provides a review of printed antennas loaded with metamaterial particles. This novel technique allows developing printed antennas with interesting features such as multifrequency (simultaneous operation over two or more frequency bands and multifunctionality (e. g. radiation pattern diversity. Moreover, compactness is also achieved and the main advantages of conventional printed antennas (light weight, low profile, low cost ... are maintained. Different types of metamaterial-loaded printed antennas are reviewed: printed dipoles and patch antennas. Several prototypes are designed, manufactured and measured showing good results. Furthermore, simple but accurate equivalent models are proposed. These models allow an easy and quick design of metamaterial-loaded printed antennas. Finally, two interesting applications based on the proposed antennas are reviewed: the patch antennas are used as radiating elements of emerging active RFID systems in the microwave band and the metamaterial-loaded printed dipoles are employed to increase the performance of log-periodic arrays.

  9. Computation of the radiation Q of dielectric-loaded electrically small antennas in integral equation formulations

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2016-01-01

    A new technique for estimating the impedance frequency bandwidth of electrically small antennas loaded with magneto-dielectric material from a single-frequency simulation in a surface integral equation solver is presented. The estimate is based on the inverse of the radiation Q computed using newly...... derived expressions for the stored energy and the radiated power of arbitrary coupled electric and magnetic currents in free space....

  10. Theoretical analysis of a parabolic torus reflector antenna with multibeam

    Institute of Scientific and Technical Information of China (English)

    杜彪; 杨可忠; 钟顺时

    1995-01-01

    The parametric equations and the formulas of unit normal vector and surface element for aparabolic torus reflector antenna are derived and the mechanism of producing multibeam is proposed, Based on physical optics, the radiation pattern formulas for the antenna are given, with which the effects of geometric parameters on the antenna are studied. The good agreement between the calculated patterns and the measured ones shows that the theory is helpful for designing parabolic torus antennas.

  11. The electronic switching spherical array antenna for the Earth Radiation Budget Spacecraft

    Science.gov (United States)

    Kudrna, K.; Hockensmith, R. P.

    1983-01-01

    The ESSA is a microprocessor-controlled antenna for low orbiting spacecraft for telemetry and command relay through the Tracking and Data Relay Satellite System (TDRSS). The array is a hemispherical shape covered with disk radiating elements. A group of radiating elements are continuously selected by the microprocessor controller to form a beam in the direction of a TDRS. A radial switching power divider uses PIN diodes to select the desired radiating elements. The antenna gain is a function of the size of the hemispherical dome. A 30-inch diameter dome is presently being built for the Earth Radiation Budget Spacecraft (ERBS). Gain of this antenna over a hemisphere is 14 dBi and polarization is lefthand circular. There are 145 radiating elements with 12 being used at one time to form a beam. The ESSA subsystem weights 74 pounds and power consumption is 20 watts. RF power handling capability is 30 watts. The S-Band radiating elements have a 10 percent bandwidth that allows simultaneous transmission and reception.

  12. On the measurement of in situ antenna radiation parameters from scattering measurements using a general scattering parametric model

    Science.gov (United States)

    Mendez, Enrique Alberto

    The new concept of antenna radiation center (ARC) is introduced and an empirical method to measure it from complex scattering data is presented. This concept is different from the well-known antenna phase center utilized in reflector antenna applications. A novel and efficient procedure based on a General Parametric Scattering Model (GSPM) is utilized to extract in-situ antenna radiation properties from complex antenna scattering data. This model based measurement approach has the advantage that it only requires two swept frequency scattering measurements in order to obtain antenna RCS, antenna gain and antenna radiation center in its integrated operational environment. The GSPM structure required to accurately extract arbitrary target scattering data is developed based on basic electromagnetic principles. The mathematical model structure consists of an early time response based on a point scattering model and on a late time response based on the Singularity Expansion Method (SEM). Both of these methods are implemented to take into account the target dispersion in a general fashion. Robust signal processing algorithms are utilized to extract the model parameters by exploiting the model symmetry properties in the time and frequency domains. In particular, super-resolution algorithms such as ESPRIT and MUSIC are utilized to extract scattering center location and resonance frequency information, while Least Squares techniques are used to estimate the different model amplitude coefficients as a function of time or frequency in an optimal (i.e. mean square sense) fashion. Theoretical derivations are provided to demonstrate that the GSPM can be utilized to extract antenna gain and radiation center information from scattering data. Synthetic and measured antenna scattering data are utilized to demonstrate the GSPM superior gain and radiation center results over traditional Fourier techniques. Gain transfer measurements results are also compared to the GSPM derived gain

  13. 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.

  14. Radiation Efficient Unidirectional Low-Profile Slot Antenna Elements for X-Band Application

    Directory of Open Access Journals (Sweden)

    C. Löcker

    2005-01-01

    Full Text Available Slots in metallic ground planes are very promising candidates for conformal antenna applications. However, a low-profile unidirectional antenna requires a back reflector close to the slot and the resulting stripline feed causes strong excitation of parallel-plate modes. In this contribution, we consider unidirectional reflector-backed slot configurations with parallel-plate mode suppression by shorting pins. Starting from a parametric study with respect to shorting pin location and back reflector distance, we present a stripline-fed rectangular slot element with radiation efficiency of more than 80% and a bandwidth of about 5% at centre frequency 10GHz. A careful optimisation of shorting pin locations guarantees reliable parallel-plate mode suppression without deteriorating the slot radiation behaviour. Coupling coefficients between parallel and aligned rectangular slot elements are presented. For increased bandwidth applications, a bow-tie slot element with about 8% bandwidth and radiation efficiency of close to 80% is proposed.

  15. Design of a Circularly Polarized Z-Slot Antenna with Isotropic Pattern for the UHF RFID Reader of WSN

    OpenAIRE

    Jongan Park; Jonghun Chun; Gwangwon Kang; Sungkwan Kang; Youngeun An

    2014-01-01

    In an antenna for a UHF RFID reader of wireless sensor networks (WSN), receiver sensitivity in sensing multitags from remote distances is an important performance index. This study designed a dual structured Z-slot antenna with optimized receiver sensitivity to enhance the sensitivity to a circularly polarized antenna with an isotropic pattern for a UHF RFID. Through analysis of performance in the designed antenna, the following was verified: return loss (S11) was about −62.21 dB at 925.25 MH...

  16. Research on Pulse Radiation Characteristics of Leaf-like Ultra Wide Band Antenna

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-qing; WANG Jun-hong; CHEN Mei-e

    2007-01-01

    A new kind of ultra wideband antenna, which consists of a leaf-like dipole and a dielectric block, is proposed and analyzed. The dielectric block is attached in parallel with the dipole near its feed point. Thus, the near field is attracted to the side where the dielectric block is located. It leads to a focusing effect of the energy in the far zone. The finitedifference time -domain (FDTD) method combined with the perfectly matched layers (PML) technique is used in the simulation of the antenna radiation characteristics. The research shows that, with proper dielectric loading and 50 Ω feeding line, the bandwidth of the antenna can be up to 6.5 GHz, from 3.5 GHz to 10 GHz with VSWR (voltage standing wave ratio) less than 2.5.

  17. Design of a Quasi-Hemispherical UWB Antenna

    DEFF Research Database (Denmark)

    Zhekov, Stanislav Stefanov; Tatomirescu, Alexandru; Franek, Ondrej;

    2016-01-01

    is employed to feed the antenna in order to assess the change of the antenna performance due to the cable effect. The simulated results show that the antenna is capable of operating in the frequency band from 7 to 32.5 GHz with S11 below -10 dB, while maintaining an omnidirectional radiation pattern...

  18. Explore the Capability of ESPAR Antennas for Low Cost Communication

    DEFF Research Database (Denmark)

    Han, Bo; Kalis, A; Papadias, C.;

    . However, for higher modulation schemes like 16-QAM, more radiation patterns are needed which require a wider control range on the parasitic antenna load. In order to explore the capability of ESPAR antennas, negative resistance was proposed, but their values cannot be easily controlled both on the real...... the capacity of ESPAR antenna for high order modulation applications....

  19. Characterization of transceive surface element designs for 7 tesla magnetic resonance imaging of the prostate: radiative antenna and microstrip

    International Nuclear Information System (INIS)

    Ultra-high field magnetic resonance (⩾7 tesla) imaging (MRI) faces challenges with respect to efficient spin excitation and signal reception from deeply situated organs. Traditional radio frequency surface coil designs relying on near-field coupling are suboptimal at high field strengths. Better signal penetration can be obtained by designing a radiative antenna in which the energy flux is directed to the target location. In this paper, two different radiative antenna designs are investigated to be used as transceive elements, which employ different dielectric permittivities for the antenna substrate. Their transmit and receive performances in terms of B+1, local SAR (specific absorption rate) and SNR (signal-to-noise ratio) were compared using extensive electromagnetic simulations and MRI measurements with traditional surface microstrip coils. Both simulations and measurements demonstrated that the radiative element shows twofold gain in B+1 and SNR at 10 cm depth, and additionally a comparable SAR peak value. In terms of transmit performance, the radiative antenna with a dielectric permittivity of 37 showed a 24% more favorable local SAR10g avg/(B+1)2 ratio than the radiative antenna with a dielectric permittivity of 90. In receive, the radiative element with a dielectric permittivity of 90 resulted in a 20% higher SNR for shallow depths, but for larger depths this difference diminished compared to the radiative element with a dielectric permittivity of 37. Therefore, to image deep anatomical regions effectively, the radiative antenna with a dielectric permittivity of 37 is favorable. (paper)

  20. Characterization of transceive surface element designs for 7 tesla magnetic resonance imaging of the prostate: radiative antenna and microstrip

    Science.gov (United States)

    Ipek, Ö.; Raaijmakers, A. J. E.; Klomp, D. W. J.; Lagendijk, J. J. W.; Luijten, P. R.; van den Berg, C. A. T.

    2012-01-01

    Ultra-high field magnetic resonance (⩾7 tesla) imaging (MRI) faces challenges with respect to efficient spin excitation and signal reception from deeply situated organs. Traditional radio frequency surface coil designs relying on near-field coupling are suboptimal at high field strengths. Better signal penetration can be obtained by designing a radiative antenna in which the energy flux is directed to the target location. In this paper, two different radiative antenna designs are investigated to be used as transceive elements, which employ different dielectric permittivities for the antenna substrate. Their transmit and receive performances in terms of B+1, local SAR (specific absorption rate) and SNR (signal-to-noise ratio) were compared using extensive electromagnetic simulations and MRI measurements with traditional surface microstrip coils. Both simulations and measurements demonstrated that the radiative element shows twofold gain in B+1 and SNR at 10 cm depth, and additionally a comparable SAR peak value. In terms of transmit performance, the radiative antenna with a dielectric permittivity of 37 showed a 24% more favorable local SAR10g avg/(B+1)2 ratio than the radiative antenna with a dielectric permittivity of 90. In receive, the radiative element with a dielectric permittivity of 90 resulted in a 20% higher SNR for shallow depths, but for larger depths this difference diminished compared to the radiative element with a dielectric permittivity of 37. Therefore, to image deep anatomical regions effectively, the radiative antenna with a dielectric permittivity of 37 is favorable.

  1. Polarized Uniform Linear Array System: Beam Radiation Pattern, Beamforming Diversity Order, and Channel Capacity

    Directory of Open Access Journals (Sweden)

    Xin Su

    2015-01-01

    Full Text Available There have been many studies regarding antenna polarization; however, there have been few publications on the analysis of the channel capacity for polarized antenna systems using the beamforming technique. According to Chung et al., the channel capacity is determined by the density of scatterers and the transmission power, which is obtained based on the assumption that scatterers are uniformly distributed on a 3D spherical scattering model. However, it contradicts the practical scenario, where scatterers may not be uniformly distributed under outdoor environment, and lacks the consideration of fading channel gain. In this study, we derive the channel capacity of polarized uniform linear array (PULA systems using the beamforming technique in a practical scattering environment. The results show that, for PULA systems, the channel capacity, which is boosted by beamforming diversity, can be determined using the channel gain, beam radiation pattern, and beamforming diversity order (BDO, where the BDO is dependent on the antenna characteristics and array configurations.

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

    Science.gov (United States)

    Kempel, Leo C.; Volakis, John L.

    1993-01-01

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

  3. MUTUAL COUPLING REDUCTION BETWEEN MICROSTRIP ANTENNAS USING ELECTROMAGNETIC BANDGAP STRUCTURE

    Directory of Open Access Journals (Sweden)

    G.N. Gaikwad

    2011-03-01

    Full Text Available When the number of antenna elements is placed in forming the arrays, mutual coupling between the antenna elements is a critical issue. This is particularly concern in phase array antennas. Mutual coupling is a potential source of performance degradation in the form of deviation of the radiation pattern from the desired one, gain reduction due to excitation of surface wave, increased side lobe levels etc. EBG (Electromagnetic Band Gap structure (also called as Photonic Bandgap Structure PBG not only enhances the performance of the patch antennas but also provides greater amount of isolation when placed between the microstrip arrays. This greatly reduces the mutual coupling between the antenna elements. The radiation efficiency, gain, antenna efficiency, VSWR, frequency, directivity etc greatly improves over the conventional patch antennas using EBG. The EBG structure and normal patch antenna is simulated using IE3D antenna simulation software.

  4. Advanced ICRF antenna design for R-TOKAMAK

    International Nuclear Information System (INIS)

    The advanced ICRF antennas designed for the R-TOKAMAK (a proposal in the Institute of Plasma Physics, Nagoya University) are described. They are a standard loop antenna and a panel heater antenna for fast wave heating, and a waveguide antenna for ion Bernstein wave heating. The standard loop antenna is made of Al-alloy and has a simple structure to install because of radioactivation by D-T neutrons. For a high power heating, a new type antenna called 'Panel heater antenna' is proposed, and it has a wide radiation area and is able to select a parallel wave number. The field pattern of the panel heater antenna is measured. The feasibility of the waveguide antenna is discussed for the ion Bernstein wave heating. The radiation from the aperture of the double ridge waveguide is experimentally estimated with a load simulating the plasma. (author)

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

    OpenAIRE

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

    2010-01-01

    Analytic time domain expressions are derived for the pulsed electromagnetic field radiated by a narrow slot antenna with a dielectric layer in a two‐dimensional model configuration. In any finite time window of observation, exact pulse shapes for the propagated, reflected, and refracted wave constituents are constructed with the aid of the modified Cagniard method (Cagniard‐DeHoop method). Numerical results are presented for vanishing slot width and field pulse shapes at the dielectric/free s...

  6. Compact metallo-dielectric optical antenna for ultra directional and enhanced radiative emission

    CERN Document Server

    Devilez, Alexis; Stout, Brian

    2010-01-01

    We report the design of highly efficient optical antennas employing a judicious synthesis of metallic and dielectric materials. In the proposed scheme, a pair of metallic coupled nanoparticles permits large enhancements in both excitation strength and radiative decay rates, while a high refractive index dielectric microsphere is employed to efficiently collect light without spoiling the emitter quantum efficiency. Our simulations indicate potential fluorescence rate enhancements of 3 orders of magnitude over the entire optical frequency range.

  7. The effect of insertion depth on the theoretical SAR patterns of 915 MHz dipole antenna arrays for hyperthermia.

    Science.gov (United States)

    James, B J; Strohbehn, J W; Mechling, J A; Trembly, B S

    1989-01-01

    Interstitial microwave antenna array hyperthermia (IMAAH) is presently used clinically in the treatment of cancer. This paper presents the theoretical specific absorption rate (SAR) patterns of 915 MHz microwave antenna arrays for varying insertion depths. The antennas were oriented in a 2 x 2 cm square array. Insertion depth, defined as distance from skin to antenna tip, ranged from 5.9 to 17.6 cm. Two different antenna configurations were considered. In the first the antenna had a distal section a quarter-wavelength long (resonant case), while the second had a distal section approximately 13% longer than a quarter-wavelength (non-resonant case). SAR patterns were calculated from theoretical expressions, and displayed as lines of constant SAR normalized to the maximum SAR value in the array. The results show that regions of concentrated power deposition or 'hotspots' occurred in the centre of the array and moved in a complex but predictable fashion as insertion depth was varied. For insertion depths shorter than a resonant half-wavelength, there occurred one hotspot distal to the antenna junctions. As insertion depth was increased beyond a resonant half-wavelength, the hotspot moved proximal to the antenna junctions and eventually split in two. For depths very much longer than a resonant half-wavelength a hotspot centred about the antenna junction dominated the SAR pattern. For the resonant case the maximum SAR was often along the central axis of the array, while for the non-resonant case the maximum SAR was at the antennas with a local maximum on the central axis. PMID:2592787

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

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

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

  9. A Compact UWB Diversity Antenna

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

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

  10. Practical realization of dual S arm antenna for beam steering applications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A dual S shaped micro strip antenna with a realistic feed is proposed for generation of tilted beam radiation pattern pertaining for beam steering applications. To achieve this, four feeding points are located at a distance of 5.6 mm from the antenna centre. These feeding points when excited one by one generate four tilted beams in four different space quadrants, thus yielding a beam steerable antenna. Importantly, since the proposed antenna is symmetrical in the structure, all the four tilted beams have the same radiation pattern characteristics. A further enhancement of the antenna bandwidth is also achieved using 100-μm capacitive coupling between the feed and the antenna strip.

  11. Hyperbolic thermal antenna

    CERN Document Server

    Barbillon, Grégory; Biehs, Svend-Age; Ben-Abdallah, Philippe

    2016-01-01

    A thermal antenna is an electromagnetic source which emits in its surrounding, a spatially coherent field in the infrared frequency range. Usually, its emission pattern changes with the wavelength so that the heat flux it radiates is weakly directive. Here, we show that a class of hyperbolic materials, possesses a Brewster angle which is weakly dependent on the wavelength, so that they can radiate like a true thermal antenna with a highly directional heat flux. The realization of these sources could open a new avenue in the field of thermal management in far-field regime.

  12. Controlling spontaneous emission with plasmonic optical patch antennas

    CERN Document Server

    Belacel, C; Bigourdan, F; Marquier, F; Hugonin, J -P; de Vasconcellos, S Michaelis; Lafosse, X; Coolen, L; Schwob, C; Javaux, C; Dubertret, B; Greffet, J -J; Senellart, P; Maitre, A

    2012-01-01

    We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk 30 nm above a thick gold layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending of the antenna size. Considering the double dipole structure of the emitters, this corresponds to a Purcell factor up to 80 for dipoles perpendicular to the disk.

  13. A Compact Diversity Antenna for Handheld Terminals

    Institute of Scientific and Technical Information of China (English)

    Hai-Lin Xiao; Zai-Ping Nie; Yu-Jing Wu

    2009-01-01

    The handheld terminals antenna should have a small size, sufficient gain and big bandwidth. In this paper, a compact planar inverted-L diversity antenna for handheld terminals is proposed. Three diversity antennas operating at 2.15 GHz are designed and the effect of important parameters of the proposed antenna is measured. The isolation is found to be better than 13 dB, the usable bandwidth is about 13%. Moreover, the measured radiation patterns are also obtained that the backward radiation is decreased.

  14. Switchable Electromagnetic Bandgap Surface Wave Antenna

    Directory of Open Access Journals (Sweden)

    Qiang Bai

    2014-01-01

    Full Text Available This paper presents a novel switchable electromagnetic bandgap surface wave antenna that can support both a surface wave and normal mode radiation for communications at 2.45 GHz. In the surface wave mode, the antenna has a monopole-like radiation pattern with a measured gain of 4.4 dBi at ±49° and a null on boresight. In the normal mode, the antenna operates like a back-fed microstrip patch antenna.

  15. Circularly Polarized Low-Profile Antenna for Radiating Parallel to Ground Plane for RFID Reader Applications

    Directory of Open Access Journals (Sweden)

    Kittima Lertsakwimarn

    2013-01-01

    Full Text Available This paper presents a low-profile printed antenna with double U-shaped arms radiating circular polarization for the UHF RFID readers. The proposed antenna consists of double U-shaped strip structures and a capacitive feeding line to generate circular polarization. A part of the U-shaped arms is bent by 90° to direct the main beam parallel to the ground plane. From the results, -10 dB |S11| and 3 dB axial ratio of the antenna cover a typical UHF RFID band from 920 MHz to 925 MHz. The bidirectional beam is obtained with the maximum gain of 1.8 dBic in the parallel direction to the ground plane at the 925 MHz. The overall size of the proposed antenna including ground plane is 107 mm × 57 mm × 12.8 mm (0.33λ0 × 0.17λ0 × 0.04λ0.

  16. CPW-Fed Slot Antenna for Wideband Applications

    OpenAIRE

    Shanmuganantham, T.; K. Balamanikandan; Raghavan, S

    2008-01-01

    A new coplanar waveguide (CPW)-fed wideband printed slot antenna is presented, and the impedance characteristics of this antenna with different sizes of tapers are discussed. The effect of tapering angle with the resonant frequency is also observed. The fundamental parameters of the antenna such as bandwidth, return loss, gain, radiation pattern, and polarization are obtained. All meets the acceptable antenna standards. The measured input impedance bandwidth (return loss < −10 dB) of the pro...

  17. A compact wideband monopole antenna fed by coplanar waveguide

    Science.gov (United States)

    Pan, Guoping; Zhao, Wenhua; Zhou, Jiang; Su, Yan; Li, Qifu

    2016-02-01

    A compact wideband printed antenna fed by coplanar waveguide (CPW) is presented in this paper. The wideband characteristic is achieved by coupling three monopole resonant modes of the proposed antenna. The proposed antenna is built and simulated to verify the design strategy. A wide impedance bandwidth of 100.5% (1.7866-5.3953 GHz) with S11antenna has stable performance, including bi-directional radiation pattern and gain. It also shows the merits of low cost and simple structure.

  18. Whistler wave radiation from a pulsed loop antenna located in a cylindrical duct with enhanced plasma density

    Energy Technology Data Exchange (ETDEWEB)

    Kudrin, Alexander V.; Shkokova, Natalya M. [Department of Radiophysics, University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Ferencz, Orsolya E. [MTA Research Centre for Astronomy and Earth Sciences, Csatkai E. u. 6–8, Sopron H-9400 (Hungary); Zaboronkova, Tatyana M. [Department of Radiophysics, University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Department of Nuclear Physics, R. E. Alekseev State Technical University of Nizhny Novgorod, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation)

    2014-11-15

    Pulsed radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is studied. The radiated energy and its distribution over the spatial and frequency spectra of the excited waves are derived and analyzed as functions of the antenna and duct parameters. Numerical results referring to the case where the frequency spectrum of the antenna current is concentrated in the whistler range are reported. It is shown that under ionospheric conditions, the presence of an artificial duct with enhanced density can lead to a significant increase in the energy radiated from a pulsed loop antenna compared with the case where the same source is immersed in the surrounding uniform magnetoplasma. The results obtained can be useful in planning active ionospheric experiments with pulsed electromagnetic sources operated in the presence of artificial field-aligned plasma density irregularities that are capable of guiding whistler waves.

  19. Generalized transmission line method to study the far-zone radiation of antennas under a multilayer structure

    CERN Document Server

    Wu, Xuan Hui

    2008-01-01

    This book gives a step-by-step presentation of a generalized transmission line method to study the far-zone radiation of antennas under a multilayer structure. Normally, a radiation problem requires a full wave analysis which may be time consuming. The beauty of the generalized transmission line method is that it transforms the radiation problem for a specific type of structure, say the multilayer structure excited by an antenna, into a circuit problem that can be efficiently analyzed. Using the Reciprocity Theorem and far-field approximation, the method computes the far-zone radiation due to

  20. Fresnel zones for ground-based antennas

    DEFF Research Database (Denmark)

    Andersen, J. Bach

    1964-01-01

    The ordinary Fresnel zone concept is modified to include the influence of finite ground conductivity. This is important for ground-based antennas because the influence on the radiation pattern of irregularities near the antenna is determined by the amplitude and phase of the groundwave. A new...

  1. An antenna design for PANSAT using NEC.

    OpenAIRE

    Ellrick, Daniel A.

    1991-01-01

    Approved for public release; distribution is unlimited In this thesis the Numerical Electromagnetics Code (NEC) is used to design an omnidirectional antenna for the Petite Amateur Navy Satellite (PANSAT). The completed antenna design uses a tangential turnstile antenna to achieve a circularly polarized radiation pattern with predicted worst nulls of approximately -3.0 dBi. The use of NEC-3, recently ported to 80386 personal computers, demonstrates the potential of personal computers for ...

  2. Polarization modulation of terahertz electromagnetic radiation by four-contact photoconductive antenna.

    Science.gov (United States)

    Hirota, Yuichi; Hattori, Ryo; Tani, Masahiko; Hangyo, Masanori

    2006-05-15

    Generation and modulation of circularly polarized terahertz electromagnetic radiation have been demonstrated by using a four-contact photoconductive antenna and a total-reflection Si prism. The quality of the circularly polarized terahertz pulsed radiation has been evaluated by using a polarization sensitive terahertz time-domain spectroscopy system. The characteristic of the dynamic modulation between the left and right circularly polarized states of the THz radiation is also evaluated. The ellipticity of the modulated circularly polarized THz radiation without a polarizer is not as good as that of the non-modulated because of the non-uniform bias field distribution and the asymmetric pump laser intensity profile on the photoconductive gap. PMID:19516602

  3. 单源单极等离子体天线辐射特性实验研究%Experimental study on radiation characteristics of single-source monopole plasma antenna

    Institute of Scientific and Technical Information of China (English)

    柳建; 王世庆; 徐灵飞

    2012-01-01

    A series of experiments have been performed to study the radiation characteristics of single-source monopole plasma antenna. The radiation intensity and pattern were measured carefully, and then the antenna's main lobe beamwidth and direction factor were derived. Through the comparison with metal antenna, the radiation efficiency of plasma antenna was fingered out. The impedance of the antenna was also measured and analyzed. The results show that plasma antenna has a similar radiation pattern and impedance as metal antenna does, and in most cases its direction factor is better than the later's. However, its radiation efficiency is lower and its stability is weaker.%为了对等离子体天线进行更深入的研究,必须结合实验获得其真实辐射特性,为此搭建了天线辐射特性测量平台,对单源单极等离子体天线的辐射特性进行了详细的实验研究.通过测量辐射远场区接收天线感应电压数据,得出了天线的辐射方向图、主旁瓣宽度和方向系数;通过与金属天线的辐射场最大值对比,得出了天线的辐射效率;通过测量输入功率和反射功率得出了天线的输入阻抗.此项工作弥补了在等离子体天线研究中实验研究不足的问题.

  4. Two-Dimensional Time-Domain Antenna Arrays for Optimum Steerable Energy Pattern with Low Side Lobes

    Directory of Open Access Journals (Sweden)

    Alberto Reyna

    2014-01-01

    Full Text Available This document presents the synthesis of different two-dimensional time-domain antenna arrays for steerable energy patterns with side lobe levels. The research is focused on the uniform and nonuniform distributions of true-time exciting delays and positions of antenna elements. The uniform square array, random array, uniform concentric ring array, and rotated nonuniform concentric ring array geometries are particularly studied. These geometries are synthesized by using the well-known sequential quadratic programming. The synthesis regards the optimal true-time exciting delays and optimal positions of pulsed antenna elements. The results show the capabilities of the different antenna arrays to steer the beam in their energy pattern in time domain and how their performance is in frequency domain after the synthesis in time domain.

  5. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    OpenAIRE

    Seung-Hyun Eom; Yunsik Seo; Sungjoon Lim

    2015-01-01

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antenn...

  6. EFFICIENT ANALYSIS OF ELECTROMAGNETIC RADIATION FROM MICROSTRIP ANTENNA USING VOLUME-SURFACE CURRENT CONTUNUITY METHOD

    Institute of Scientific and Technical Information of China (English)

    Yuan Jiade; Su Kaixiong; Ye Yuhuang

    2012-01-01

    The Volume-Surface Current Continuity Method (VSCCM) is presented to analyze electromagnetic radiation from microstrip antenna.The microstrip antenna is discretized into small triangular patches on conducting surface and tetrahedral volume cells in dielectric region.The Method of Moments (MoM) is applied to solve the integral equation.An equation contains the restriction relation between the volume and surface current coefficient is derived from the current continuity equation at those parts where the conducting surface is in contact with the dielectric material.A simple equivalent strip model is introduced in the treatment of the feeding probe in VSCCM.The VSCCM can reduce the unknowns required to be solved in MoM,as well as the condition number of the matrix equation.Numerical results are given to validate the accuracy and efficiency of this method.

  7. Radiation Characteristic Improvement of X-Band Slot Antenna Using New Multiband Frequency-Selective Surface

    Directory of Open Access Journals (Sweden)

    Elham Moharamzadeh

    2014-01-01

    Full Text Available A new configuration of frequency-selective surfaces (FSSs is designed and presented with multiresonance characteristics which covers all of the frequency domain of X-band from 8 to 12 GHz. The proposed FSS comprises three conductor-based split ring resonators, connected together. In this design, two unit cells of the FSS with different lengths are employed side by side to design the FSS. The FSS is used to enhance the gain of the new designed triangle slot antenna at X-band. The proposed FSS is analyzed by using reflected-wave unit-cell box method. The single, double, and array of the FSS cells are studied. Next, the designed FSS along with the antenna is analyzed. The measurement and simulated results of the impedance and radiation characteristics, especially the increment of the gain, are presented.

  8. Experiments on Broadband EMP Radiation with an Axial Mode Helix Antenna

    Institute of Scientific and Technical Information of China (English)

    SUN Qi-Zhi; FANG Dong-Fan; LIU Wei; LIU Zheng-Fen; CHI Yuan; DAI Wen-Feng; HAN Wen-Hui

    2011-01-01

    @@ To produce broadband electromagnetic pulse(EMP)radiation,we design and test a sub-ns pulse system which is utilized to drive an axial mode helix antenna.This sub-ns pulse system consists of a 10-stage Marx generator,an intermediate storage capacitor,an impedance transforming line,and can generate a high voltage of 570kV with a rise time of 1-1.5ns on a 300-Ω-resistance load.The diameter,pitch and turns of the helix antenna are 29 cm,19.5cm and 5,respectively,with a design frequency of 300 MHz.When the charging voltage of the Marx generator is 30kV,the electric field of radiated EMP measured 3m from the source is 35kV/m with a central frequency of 250MHz.The relatively spectral bandwidth is 25%.The radiated EMP results are reproducible and the system will work in repetition mode if the available do power is utilized.%To produce broadband electromagnetic pulse (EMP) radiation, we design and test a sub-ns pulse system which is utilized to drive an axial mode helix antenna. This sub-ns pulse system consists of a 10-stage Marx generator, an intermediate storage capacitor, an impedance transforming line, and can generate a high voltage of 570kV with a rise time of 1-1.5 ns on a 300-Q-resistance load. The diameter, pitch and turns of the hetix antenna are 29 cm, 19.5 cm and 5, respectively, with a design frequency of 300 MHz. When the charging voltage of the Marx generator is 30 kV, the electric field of radiated EMP measured 3m from the source is 35kV/m with a central frequency of 250 MHz. The relatively spectra] bandwidth is 25%. The radiated EMP results are reproducible and the system will work in repetition mode if the available dc power is utilized.

  9. Mitigating illumination gradients in a SAR image based on the image data and antenna beam pattern

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W.

    2013-04-30

    Illumination gradients in a synthetic aperture radar (SAR) image of a target can be mitigated by determining a correction for pixel values associated with the SAR image. This correction is determined based on information indicative of a beam pattern used by a SAR antenna apparatus to illuminate the target, and also based on the pixel values associated with the SAR image. The correction is applied to the pixel values associated with the SAR image to produce corrected pixel values that define a corrected SAR image.

  10. 47 CFR 73.6025 - Antenna system and station location.

    Science.gov (United States)

    2010-10-01

    ... RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6025 Antenna system and station... should be used for the maximum radiation. The plot of the pattern should be oriented so that 0 degrees (True North) corresponds to the maximum radiation of the directional antenna or, alternatively in...

  11. Wideband blade monopole antenna with sleeved coaxial feed

    OpenAIRE

    Morrow, I. L.; Dingley, G.; Cooper, A.

    2009-01-01

    A wideband planar monopole antenna requiring a small ground plane is described. Numerical and measured results confirms the antenna has good radiation efficiency and stable omni-directional radiation patterns over an impedance bandwidth of 4.1:1 covering the 200-850 MHz frequency spectrum.

  12. Modeling radiative properties of nanoscale patterned wafers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Temperature nonuniformity in rapid thermal processing of wafers is a critical problem facing the semiconductor industry. One cause of the problem is the nonuniform absorption of thermal radiation in patterned wafers where the optical properties vary across the wafer surface. This paper presents a parametric study of the radiative properties of patterned wafers, considering the effect of temperature, wavelength, and polarization. The finite-difference time-domain (FDTD) method is employed to examine the effect of various trench sizes on the radiative properties via numerically solving the Maxwell equations. The effective medium theory (EMT) is also used to help explain the absorptance prediction. The results show that in the cases with trench size variation, the resonance cavity effect may increase the absorptance as the trench width increases. And in the cases with trench size increasing at several different filling ratios, the absorptance does not change much at small filling ratio. The effects of the resonant cavity, diffraction, wave interferences on the spectral-directional absorptance were also discussed. This work is of great importance for optimization of advanced annealing techniques in semiconductor manufacturing.

  13. Living antennas on communication satellites

    DEFF Research Database (Denmark)

    Lumholt, Michael

    2003-01-01

    Crises change the global pattern of communication. The communications problems occur because the satellites are optimized to cover specific geographic areas, and these areas cannot be altered once the satellites are in Earth orbit. An effective solution to the problem is to equip communication sa...... satellites with "living" antennas that can adjust their radiation coverage areas according to the new demands. The development of living antennas is, therefore, among the focus areas identified and supported by the European Space Agency, ESA....

  14. Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores

    DEFF Research Database (Denmark)

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

    2014-01-01

    For spherical antennas consisting of a solid magnetodielectric lossy core with an impressed surface current density exciting a superposition of the ${\\rm TE}_{mn}$ and ${\\rm TM}_{mn}$ spherical modes, we analytically determine the radiation quality factor $Q$ and radiation efficiency $e$ . Also, we...

  15. A tunable microwave slot antenna based on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Dragoman, Mircea; Aldrigo, Martino; Vasilache, D.; Dinescu, A. [National Institute for Research and Development in Microtechnology (IMT), Str. Erou Iancu Nicolae 126 A, 077190 Bucharest-Voluntari (Romania); Neculoiu, Dan; Bunea, Alina-Cristina, E-mail: alina.bunea@imt.ro [National Institute for Research and Development in Microtechnology (IMT), Str. Erou Iancu Nicolae 126 A, 077190 Bucharest-Voluntari (Romania); “Politehnica” University of Bucharest, Bd. Iuliu Maniu 1-3, 061071, Bucharest (Romania); Deligeorgis, George; Konstantinidis, George [Foundation for Research and Technology Hellas (FORTH), P.O. Box 1527, Vassilika Vuton, Heraklion 71110, Crete, Hellas (Greece); Mencarelli, Davide; Pierantoni, Luca [Università Politecnica delle Marche, via Brecce Bianche 12, 60131 Ancona (Italy); Modreanu, M. [Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork (Ireland)

    2015-04-13

    The paper presents the experimental and modeling results of a microwave slot antenna in a coplanar configuration based on graphene. The antennas are fabricated on a 4 in. high-resistivity Si wafer, with a ∼300 nm SiO{sub 2} layer grown through thermal oxidation. A CVD grown graphene layer is transferred on the SiO{sub 2}. The paper shows that the reflection parameter of the antenna can be tuned by a DC voltage. 2D radiation patterns at various frequencies in the X band (8–12 GHz) are then presented using as antenna backside a microwave absorbent and a metalized surface. Although the radiation efficiency is lower than a metallic antenna, the graphene antenna is a wideband antenna while the metal antennas with the same geometry and working at the same frequencies are narrowband.

  16. New Diamond Antenna for Ultra Wideband Applications

    Directory of Open Access Journals (Sweden)

    Ziani Kerarti Djalal

    2012-07-01

    Full Text Available There has been a flourishing prospect of UWB technology in recent years in both communication and other purposes like microwave imaging and radar applications. Recent studies of UWB antenna structures are specially concentrated on microstrip , slot and planar monopole antennas . In this work, a small monopole antenna with diamond shape of the patch (30 x 26 mm printed microstrip fed monopole antenna has been designed, some parameters like return loss (S11, Voltage Standing Wave Ratio (VSWR, radiation pattern has been performed to test the validity of simulation and verify eligibility of the antenna for the wireless communications purpose. The proposed antenna is simulated in CST Microwave Studio and has surpassed the bandwidth of UWB requirement, which is from 3.1 GHz to 10.6 GHz, and exhibits good UWB characteristics. The 10 dB return loss bandwidth of this antenna element is from 3.39 GHz to more than 14 GHz.

  17. Microstrip Antenna Generates Circularly Polarized Beam

    Science.gov (United States)

    Huang, J.

    1986-01-01

    Circular microstrip antenna excited with higher order transverse magnetic (TM) modes generates circularly polarized, conical radiation patterns. Found both theoretically and experimentally that peak direction of radiation pattern is varied within wide angular range by combination of mode selection and loading substrate with materials of different dielectric constants.

  18. Analysis of equivalent antenna based on FDTD method

    Institute of Scientific and Technical Information of China (English)

    Yun-xing YANG; Hui-chang ZHAO; Cui DI

    2014-01-01

    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 air)takes 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.

  19. 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.

  20. Efficient Radiation by Electrically Small Antennas made of Coupled Split-ring Resonators

    Science.gov (United States)

    Peng, Liang; Chen, Peiwei; Wu, Aiting; Wang, Gaofeng

    2016-09-01

    In this paper, coupled split-ring resonators (SRRs) are used to construct the electrically small antennas. We show that through strong magnetic coupling, the coupled SRRs composite can oscillate at a wavelength much larger than its total size. Due to its magnetic dipole feature, the coupled SRRs composite allows the electromagnetic (EM) power to radiate and hence forms the electrically small antenna (ESA). Because of the high-Q resonance, the ESA could be easily matched to the driving circuit in the microwave region, through mutual induction approach. We also demonstrate that the radiation efficiency of such ESAs can be drastically improved if the current distribution on individual SRRs is similar, which is achievable by carefully designing the ESAs. From our simulations and experimental measurements, the ESAs’ radiation efficiency can reach up to 41%, with relative footprint of 0.05λ0 × 0.05λ0. Our approach would be an effective way to realize ESAs with high efficiency, which can be implemented on chip through the standard planar lithography.

  1. Experiments on Broadband EMP Radiation with an Axial Mode Helix Antenna

    International Nuclear Information System (INIS)

    To produce broadband electromagnetic pulse (EMP) radiation, we design and test a sub-ns pulse system which is utilized to drive an axial mode helix antenna. This sub-ns pulse system consists of a 10-stage Marx generator, an intermediate storage capacitor, an impedance transforming line, and can generate a high voltage of 570 kV with a rise time of 1–1.5 ns on a 300-Ω-resistance load. The diameter, pitch and turns of the helix antenna are 29 cm, 19.5 cm and 5, respectively, with a design frequency of 300 MHz. When the charging voltage of the Marx generator is 30 kV, the electric field of radiated EMP measured 3m from the source is 35 kV/m with a central frequency of 250 MHz. The relatively spectral bandwidth is 25%. The radiated EMP results are reproducible and the system will work in repetition mode if the available dc power is utilized. (general)

  2. Microstrip Antenna

    OpenAIRE

    Anuj Mehta

    2015-01-01

    Abstract This article presents an overview of the microstrip patch antenna and its design techniques. Basically a microstrip patch antenna comprises of a trace of copper or any other metal of any geometry on one side of a standard printed circuit board substrate with other side grounded. The antenna is fed using various feeding techniques like coaxial strip line aperture coupling or proximity coupling techniques. The working principle and the radiation mechanism have also been described. The ...

  3. New band-notched UWB antenna

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-xiang; DENG Hong-wei

    2009-01-01

    A simple and compact ultra wideband (UWB) printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented.

  4. Design of an Impulse Radiating Antenna Using a Curved TEM-Wire Fed Parabola

    Directory of Open Access Journals (Sweden)

    Donghyun Lee

    2012-01-01

    Full Text Available A design procedure for a TEM-wire fed parabolic antenna is given for impulse radiation, which is suitable for low cost fabrication. A simple wire-type TEM horn and a parabolic reflector are used to achieve ultra-wide bandwidth and high directivity at the same time. Equations for parametric curves of a TEM-wire horn are presented and are used to investigate the relation among their shapes, bandwidth, and directivity. It is also found that wire separation near the focal point limits the high frequency directivity.

  5. Fast 3D Pattern Synthesis with Polarization and Dynamic Range Ratio Control for Conformal Antenna Arrays

    Directory of Open Access Journals (Sweden)

    Massimiliano Comisso

    2014-01-01

    Full Text Available This paper proposes an iterative algorithm for the 3D synthesis of the electric far-field pattern of a conformal antenna array in the presence of requirements on both the polarization and the dynamic range ratio (DRR of the excitations. Thanks to the use of selectable weights, the algorithm allows a versatile control of the DRR and of the polarization in a given angular region and requires a low CPU time to provide the array excitations. Furthermore, a modified version of the algorithm is developed to enable the optimization of the polarization state by phase-only control. Numerical results are presented to verify the usefulness of the proposed approach for the joint pattern and polarization synthesis of conformal arrays with reduced or even unitary DRR.

  6. Whip antenna design for portable rf systems

    Science.gov (United States)

    Ponnapalli, Saila; Canora, Frank J.

    1995-12-01

    Whip type antennas are probably the most commonly used antennas in portable rf systems, such as cordless and cellular phones, rf enabled laptop computers, personal digital assistants (PDAs), and handheld computers. Whip antennas are almost always mounted on the chassis which contains the radio and other electronics. The chassis is usually a molded plastic which is coated with a conducting paint for EMI purposes. The chassis which appears as a lossy conductor to the antenna, has several effects -- detuning, altering the gain of the antenna, and shadowing its radiation pattern. Extensive modeling and measurements must be performed in order to fully characterize the affects of the chassis on the whip antenna, and to optimize antenna type, orientation and position. In many instances, modeling plays a more important role in prediction of the performance of whip antennas, since measurements become difficult due to the presence of common mode current on feed cables. In this paper models and measurements are used to discuss the optimum choice of whip antennas and the impact of the chassis on radiation characteristics. A modeling tool which has been previously described and has been successfully used to predict radiated field patterns is used for simulations, and measured and modeled results are shown.

  7. A Wideband End-Fire Conformal Vivaldi Antenna Array Mounted on a Dielectric Cone

    Directory of Open Access Journals (Sweden)

    Zengrui Li

    2016-01-01

    Full Text Available The characteristics of a novel antipodal Vivaldi antenna array mounted on a dielectric cone are presented. By employing antipodal Vivaldi antenna element, the antenna array shows ultrawide bandwidth and end-fire radiation characteristics. Our simulations show that the cone curvature has an obvious influence on the performance of the conformal antenna, in terms of both the bandwidth and the radiation patterns. The thickness and permittivity of the dielectric cone have an effect on the bandwidth of the conformal antenna. Measurement results of both single antenna and conformal antenna array show a good agreement with the simulated results. The measured conformal antenna can achieve a −10 dB S11 with bandwidth of 2.2–12 GHz and demonstrate a typical end-fire radiation beam. These findings provide useful guidelines and insights for the design of wideband end-fire antennas mounted on a dielectric cone.

  8. Enhancing and redirecting carbon nanotube photoluminescence by an optical antenna.

    Science.gov (United States)

    Böhmler, Miriam; Hartmann, Nicolai; Georgi, Carsten; Hennrich, Frank; Green, Alexander A; Hersam, Mark C; Hartschuh, Achim

    2010-08-01

    We observe the angular radiation pattern of single carbon nanotubes' photoluminescence in the back focal plane of a microscope objective and show that the emitting nanotube can be described by a single in-plane point dipole. The near-field interaction between a nanotube and an optical antenna modifies the radiation pattern that is now dominated by the antenna characteristics. We quantify the antenna induced excitation and radiation enhancement and show that the radiative rate enhancement is connected to a directional redistribution of the emission. PMID:20721031

  9. 基于TEM喇叭的辐射波模拟器天线辐射性能研究%Research on Antenna Radiation Performance of Radiating-wave Simulator Antenna Based on TEM

    Institute of Scientific and Technical Information of China (English)

    王赟; 陈永光; 王庆国; 范丽思; 刘宗战

    2012-01-01

    It gives a research on the performance of TEM horn antenna used in the radiating - wave simulator. The impact of antenna performance parameters such as structure angle, antenna length, width - to - height ratio on the antenna radiation performance is analyzed. In order to enhance the low - frequency radiation capability, two methods are put forward to add the effective antenna length. Results suggest that both methods can improve the radiating field waveforms to some extent. With the choice of antenna length conforming to actual practice, the paper acquires good waveforms by the way of setting proper width - to - height and adding the effective antenna length.%研究了基于TEM喇叭天线的辐射波模拟器天线性能,分析了天线性能参数如结构角、天线长度、宽高比等对天线辐射性能的影响.为了提高天线低频辐射能力,提出了2种增加天线有效长度的方法,结果表明两种方法均在一定程度上对辐射场波形有所改善.在天线长度的选择符合工程实际的条件下,通过选择合适的宽高比和增加天线有效长度的方法取得了较好的场波形.

  10. Double-slot antennas on extended hemispherical dielectric lenses

    Science.gov (United States)

    Filipovic, Daniel F.; Gearhart, Steve J.; Kormanyos, Brian K.; Rebeiz, Gabriel M.

    1992-01-01

    An investigation of the coupling efficiencies to a gaussian-beam of a double-slot antenna on a hyperhemispherical lens is presented. It is shown that both lenses couple equally well to an appropriate gaussian beam (about 80 percent). The radiation patterns of both lenses with a double-slot antenna are computed using the ray-tracing method. The experimental radiation patterns are presented and show close agreement to the theoretically computed patterns.

  11. Antenna with distributed strip and integrated electronic components

    Science.gov (United States)

    Rodenbeck, Christopher T.; Payne, Jason A.; Ottesen, Cory W.

    2008-08-05

    An antenna comprises electrical conductors arranged to form a radiating element including a folded line configuration and a distributed strip configuration, where the radiating element can be in proximity to a ground conductor and/or arranged as a dipole. Embodiments of the antenna include conductor patterns formed on a printed wiring board, having a ground plane, spacedly adjacent to and coplanar with the radiating element. An antenna can comprise a distributed strip patterned on a printed wiring board, integrated with electronic components mounted on top of or below the distributed strip, and substantially within the extents of the distributed strip. Mounting of electronic components on top of or below the distributed strip has little effect on the performance of the antenna, and allows for realizing the combination of the antenna and integrated components in a compact form. An embodiment of the invention comprises an antenna including a distributed strip, integrated with a battery mounted on the distributed strip.

  12. Investigation of a Short Conical Helix Antenna

    OpenAIRE

    Nakano, Hisamatsu; Mikawa, Takao; Yamauchi, Junji

    1985-01-01

    The input impedance, radiation pattern, axial ratio, and power gain of a conical helix antenna with a short arm are calculated as a function of frequency, using theoretically determined current distributions. It is shown that the antenna radiates a circularly polarized wave over a frequency range ratio of about 1:1.2, having a power gain of about 7.7 dB. The experimental results are also presented.

  13. Wideband Monopole Antenna for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Muhammad Umar

    2013-03-01

    Full Text Available This paper presents a circular patch antenna for WLAN applications with wideband characteristics. It is shown that impedance of the antenna is matched over wideband by using the partial ground plane and quarter wave transformer with slotted TX-Line. Ansoft HFSS is used for simulation tool to map the numerical results for the return loss frequency behavior of antenna. Measure of bandwidth, return loss and radiation pattern are also reported with satisfactory performance. As the patch is circular in shape so substrate is kept in the same shape. The shape of the substrate is also discussed in details for specific antenna designs.

  14. Analysis on two novel spherical helical antennas

    Institute of Scientific and Technical Information of China (English)

    Hou ZHANG; Yingzeng YIN; Dongyu XIA

    2009-01-01

    Two novel spherical helical antennas are designed by projecting the planar equiangular spiral antenna onto hemisphere and partial sphere surfaces.Their radiation properties are analyzed by the moment method with curved basis and test function,and the curves of the voltage standing wave ratio (VSWR),gain,polarization and pattern that change with frequency are also given,respectively.It can be seen that the circular polarization band of the novel hemispherical helical antenna is broader.The gain curve of the partial spherical helical antenna is flatter and the structure is simpler.

  15. Omnidirectional, circularly polarized, cylindrical microstrip antenna

    Science.gov (United States)

    Stanton, Philip H. (Inventor)

    1985-01-01

    A microstrip cylindrical antenna comprised of two concentric subelements on a ground cylinder, a vertically polarized (E-field parallel to the axis of the antenna cylinder) subelement on the inside and a horizontally polarized (E-field perpendicular to the axis) subelement on the outside. The vertical subelement is a wraparound microstrip radiator. A Y-shaped microstrip patch configuration is used for the horizontally polarized radiator that is wrapped 1.5 times to provide radiating edges on opposite sides of the cylindrical antenna for improved azimuthal pattern uniformity. When these subelements are so fed that their far fields are equal in amplitude and phased 90.degree. from each other, a circularly polarized EM wave results. By stacking a plurality of like antenna elements on the ground cylinder, a linear phased array antenna is provided that can be beam steered to the desired elevation angle.

  16. Super wideband characteristics of monopolar patch antenna

    Directory of Open Access Journals (Sweden)

    Xi Chen

    2013-12-01

    Full Text Available A simple method of acquiring super wideband characteristics for monopolar patch antenna is proposed. Through adopting a modified cone as feeding and radiating structure, the monopolar patch antenna can reach the impedance bandwidth of more than 1:23.4 for voltage standing wave ratio (VSWR ≤ 2. In the whole operating band, the antenna has the like-monopole omnidirectional radiation patterns and the peak gains of 3.8–8.7 dB. Meanwhile, the height of the antenna is just 0.074λ(c, and the diameter of the radiated body is 0.205λ(c, which is smaller than other ultra-wideband omnidirectional antenna.

  17. Thermal effect of microwave antenna radiation on a generic model of thyroid gland

    Science.gov (United States)

    Gavriloaia, Gheorghe; Gavriloaia, Mariuca-Roxana; Ghemigean, Adina-Mariana

    2010-11-01

    The rapid diffusion of wireless communication systems has caused an increased concern for the potential detrimental effects on human health deriving from exposure to electromagnetic field. It penetrates the body and acts on all the organs, altering the cell membrane potential and the distribution of ions and dipoles. The thyroid gland is one of the most exposed vital organs and may be a target for electromagnetic radiation. This paper presents the computed temperature and specific absorption rate inside to a generic model of a human thyroid using signals radiated by an antenna operating in the 2450 MHz band and the power density levels up to 100 W/cm2. Calculations were carried out using the Finite Difference Time Domain method for the solving of two coupled differential equations, Maxwell and Pennes. The results show that the temperature can rise up to very dangerous levels, i.e., 46 °C, in a very short time. The estimated temperature distribution in the human thyroid due to exposure from microwave signals can be used to design the dangerous aria for personal working around high power emitted antenna and for medical applications.

  18. The Radiation Environment for the LISA/Laser Interferometry Space Antenna

    Science.gov (United States)

    Barth, Janet L.; Xapsos, Michael; Poivey, Christian

    2005-01-01

    The purpose of this document is to define the radiation environment for the evaluation of degradation due to total ionizing and non-ionizing dose and of single event effects (SEES) for the Laser Interferometry Space Antenna (LISA) instruments and spacecraft. The analysis took into account the radiation exposure for the nominal five-year mission at 20 degrees behind Earth's orbit of the sun, at 1 AU (astronomical unit) and assumes a launch date in 2014. The transfer trajectory out to final orbit has not yet been defined, therefore, this evaluation does not include the impact of passing through the Van Allen belts. Generally, transfer trajectories do not contribute significantly to degradation effects; however, single event effects and deep dielectric charging effects must be taken into consideration especially if critical maneuvers are planned during the van Allen belt passes.

  19. Modification and verification of an antenna design for Petite Amateur Navy Satellite (PANSAT) using NEC

    OpenAIRE

    Karapinar, Ercument

    1995-01-01

    In this thesis, a tangential turnstile antenna is modified and verified for the Petite Amateur Navy Satellite (PANSAT). The Numerical Electromagnetics Code (NEC) is used to model the antenna system. The final design provides a circularly polarized, omnidirectional radiation pattern with maximum nulls of -2.7 dRi. Two alternative antenna feed systems are proposed. NA NA Turkish Army author.

  20. Theoretical and numerical studies on cage antenna of EMP radiating-wave simulator based on parallel computing

    International Nuclear Information System (INIS)

    Large electromagnetic pulse (EMP) simulation equipment are needed in order to study the EMP effect produced by nuclear blast and reinforce measure of electron system. Considering the target is electrically large, a parallelized finite difference time domain (FDTD) algorithm based on MPI platform, combined with antenna theory, is presented for analysis of the radiation characteristics of the biconical-cylindrical cage antenna fed through the coaxial transmission line and excited by a double-exponential pulse, which can not be done on a personal computer due to over long time and prohibitive computation resources. The number of total cells for parallelized FDTD computing is about 2 billion. Numerical results show that cage antenna radius do not have a significant effect on the rise time and the peak value of the radiated electric field when the cage antenna radius is more than 3.5 m. In addition, the reflection and the loss from the ground have a great effect on the rise time, the peak value and pulse width of the radiated E-field in the horizontal plan above the ground up to 0.5 m and have little effect on the rise time and the peak value of the radiated E-field in the horizontal plan above the ground up to 6 m except the pulse width of the radiated E-field at the same point. It is found that nearer to the ground, faster the decrease of the peak value. (authors)

  1. A Novel Broadband Antenna with Pattern Reconfigurability%一种新型宽带方向图可重构天线

    Institute of Scientific and Technical Information of China (English)

    王任; 王秉中; 丁霄

    2016-01-01

    设计了一种具有两个辐射模式的宽带方向图可重构天线。该天线由两个准八木天线单元组成,两个单元的辐射体分别指向相反的方向。两个单元使用同一根同轴线从背面馈电,在每个单元的馈线与同轴线馈点之间安装一个PIN二极管以控制辐射模式。在天线振子的下方安装反射板用以调节天线的辐射方向,避免了天线对射频组件的干扰。仿真结果显示,天线的工作频段为5.00~5.65 GHz,两种模式的主瓣分别指向θ=±55°,3 dB波瓣宽度均为110°,工作频段内增益为7.3~7.7 dB,调节反射板的尺寸可以改变天线的主瓣指向。对该天线进行了实际制作和测量,实测结果和仿真结果较吻合。该天线可以用于智能通信系统。%A novel wideband antenna with two reconfigurable radiating patterns is presented. The proposed antenna is made of two quasi-Yagi antennas, with their radiations directing to opposite directions, respectively. The two elements are fed with one coaxial cable from the back of the dielectric substrate. A PIN diode is embedded between the feeding line of each element and coaxial cable to regulate the radiating pattern. Besides, reflectors are set under the arms of the driver dipole to regulate the radiating direction and avoid interference with radio components. Simulated results show that the proposed antenna can work at 5.00 GHz to 5.65 GHz, the main beams of the two modes direct to±55° respectively, and the 3dB beam-widths of main beams are all 110°. The gain within the operating bandwidth is 7.3 dB to 7.7 dB. The main beam direction of the proposed antenna can be regulated by the size of reflectors. The antenna was fabricated and measured. The measurement results are good with the simulation results. The antenna presented can be used in intelligent communication systems.

  2. A COMPACT CIRCULARLY POLARIZED SLOTTED MICROSTRIP ANTENNA

    Directory of Open Access Journals (Sweden)

    V. Jebaraj

    2014-12-01

    Full Text Available Slot antennas are often used at UHF and microwave frequencies. In slot antenna for RFID reader applications the frequency ranges from 902-923MHz to achieve circular polarization. The shapes and size of the slot, as well as the driving frequency, determine the radiation distribution pattern. The proposed compact size circularly polarized slotted microstrip antenna are summarized with design rules. The circularly polarized radiation in square patch antenna can be obtained by perturbation technique with different shapes of slot in the orthogonal direction. A single feed configuration based symmetric slotted microstrip antenna is adapted to realize the compact circularly polarized microstrip antennas. Based on the perimeter, the size of the slot on microstrip slot antenna are studied and compared. The Operating frequency of the antenna is 912MHz that can be tuned by varying the perimeter of the slot while the keeping the circularly polarized radiation unchanged. The schematic and layout are configured by using Advanced Design System (ADS. Return loss, Resonant Frequency, Axial Ratio (AR, and Gain were determined for the proposed system using ADS. A measured 3dB Axial Ratio (AR bandwidth around 6MHz with 16MHz impedance bandwidth has been achieved for the antenna on a RO3004C substrate with dielectric constant 3.38.

  3. Improved Modeling of Open Waveguide Aperture Radiators for use in Conformal Antenna Arrays

    Science.gov (United States)

    Nelson, Gregory James

    Open waveguide apertures have been used as radiating elements in conformal arrays. Individual radiating element model patterns are used in constructing overall array models. The existing models for these aperture radiating elements may not accurately predict the array pattern for TEM waves which are not on boresight for each radiating element. In particular, surrounding structures can affect the far field patterns of these apertures, which ultimately affects the overall array pattern. New models of open waveguide apertures are developed here with the goal of accounting for the surrounding structure effects on the aperture far field patterns such that the new models make accurate pattern predictions. These aperture patterns (both E plane and H plane) are measured in an anechoic chamber and the manner in which they deviate from existing model patterns are studied. Using these measurements as a basis, existing models for both E and H planes are updated with new factors and terms which allow the prediction of far field open waveguide aperture patterns with improved accuracy. These new and improved individual radiator models are then used to predict overall conformal array patterns. Arrays of open waveguide apertures are constructed and measured in a similar fashion to the individual aperture measurements. These measured array patterns are compared with the newly modeled array patterns to verify the improved accuracy of the new models as compared with the performance of existing models in making array far field pattern predictions. The array pattern lobe characteristics are then studied for predicting fully circularly conformal arrays of varying radii. The lobe metrics that are tracked are angular location and magnitude as the radii of the conformal arrays are varied. A constructed, measured array that is close to conforming to a circular surface is compared with a fully circularly conformal modeled array pattern prediction, with the predicted lobe angular locations and

  4. Cavity-Backed Dipole Antenna for Intelligent Lock Communication

    Directory of Open Access Journals (Sweden)

    Bo Yuan

    2013-01-01

    Full Text Available This paper introduces a 20*40 mm2 planar folded L-shaped dipole antenna operated under surroundings of an iron cavity for intelligent lock communication. The height of the slot antenna is shortened and the bandwidth for 2.4 GHz band has been widened. This antenna provides a solution for antenna surrounded by metal background. Good performances on return loss, radiation pattern are obtained over 2.4 GHz operating bands. The operation distance in front and back sides for the antenna has been calculated by Friis transmission equation.

  5. Simulation and Design of X-Band Conformal Antenna on Airborne Craft with Omni-directional Radiation%X波段全向共形机载天线的仿真与设计

    Institute of Scientific and Technical Information of China (English)

    韩振平; 钱祖平; 倪为民; 刘宗全

    2011-01-01

    针对工作于X频段的机载雷达天线的技术设计,使该天线由矩形平面天线与柱体共形,通过共面波导方式对其进行馈电.天线单元采用介电常数2.55,厚度为0.2mm的薄介质板.利用HFSS12对平面天线和共形天线进行仿真设计,对比了平面天线与共形天线的阻抗特性和辐射特性的变化.实验结果表明,共形后的天线带宽变大,增益提高,波束宽度展宽.在X波段内实现了低仰角扫描和方位面的全向扫描,实测阻抗带宽为7.0~12.5GHz,最大增益可达4dB,辐射特性稳定,满足机载天线的性能指标,可用作机载雷达天线单元.%A cylindrical conformal antenna operation at X band is designed. Firstly, a planar antenna is designed and analyzed, and then it is mounted on a cylindrical surface to form a conform antenna. It is fed by CPW and the permittivity of the substrate is 2.55 and its thickness is only 0.2mm. It is simulated and optimized by using the soft of HFSS 12. Comparing the impedance characteristic and radiation patterns between the planar antenna and the conformal antenna, the experimental results show the conformal antenna has a broader bandwidth and 3dB beam-width and higher gain than the planar antenna, and it has low elevation scanning and Omni-directional radiation patterns at the"X band. The measured impedance bandwidth of conformal antenna covers from 7.0~12.5GHz, the maximum gain is 4dB and radiation performance is stable. The antenna satisfies the capability of airborne antenna well so it can be used in the airborne radar system.

  6. Millimeter-wave and terahertz integrated circuit antennas

    Science.gov (United States)

    Rebeiz, Gabriel M.

    1992-11-01

    This paper presents a comprehensive review of integrated circuit antennas suitable for millimeter and terahertz applications. A great deal of research was done on integrated circuit antennas in the last decade and many of the problems associated with electrically thick dielectric substrates, such as substrate modes and poor radiation patterns, have been understood and solved. Several new antennas, such as the integrated horn antenna, the dielectric-filled parabola, the Fresnel plate antenna, the dual-slot antenna, and the log-periodic and spiral antennas on extended hemispherical lenses, have resulted in excellent performance at millimeter-wave frequencies, and are covered in detail in this paper. Also, a review of the efficiency definitions used with planar antennas is given in detail in the appendix.

  7. A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot

    Science.gov (United States)

    Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela

    2016-03-01

    The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.

  8. Smart Antenna for Cellular Mobile Communication

    CERN Document Server

    Jain, R K; Agrawal, N K

    2012-01-01

    The adoption of smart / adaptive antenna techniques in future wireless systems is expected to have a significant impact on the efficient use of the spectrum, the minimization of the cost of establishing new wireless networks, the optimization of service quality and realization of transparent operation across multi technology wireless networks [1]. This paper presents brief account on smart antenna (SA) system. SAs can place nulls in the direction of interferers via adaptive updating of weights linked to each antenna element. SAs thus cancel out most of the co-channel interference resulting in better quality of reception and lower dropped calls. SAs can also track the user within a cell via direction of arrival algorithms [2]. This paper explains the architecture, evolution and how the smart / adaptive antenna differs from the basic format of antenna. The paper further explains about the radiation pattern of the antenna and why it is highly preferred in its relative field. The capabilities of smart / adaptive ...

  9. Orthogonal feeding techniques for tapered slot antennas

    Science.gov (United States)

    Lee, Richard Q.; Simons, Rainee N.

    1998-01-01

    For array of "brick" configuration there are electrical and mechanical advantages to feed the antenna with a feed on a substrate perpendicular to the antenna substrate. Different techniques have been proposed for exciting patch antennas using such a feed structure.Rncently, an aperture-coupled dielectric resonator antenna using a perpendicular feed substrate has been demonstrated to have very good power coupling efficiency. For a two-dimensional rectangular array with tapered slot antenna elements, a power combining network on perpendicular substrate is generally required to couple power to or from the array. In this paper, we will describe two aperture-coupled techniques for coupling microwave power from a linearly tapered slot antenna (LTSA) to a microstrip feed on a perpendicular substrate. In addition, we will present measured results for return losses and radiation patterns.

  10. Accurate determination of antenna directivity

    DEFF Research Database (Denmark)

    Dich, Mikael

    1997-01-01

    The derivation of a formula for accurate estimation of the total radiated power from a transmitting antenna for which the radiated power density is known in a finite number of points on the far-field sphere is presented. The main application of the formula is determination of directivity from power......-pattern measurements. The derivation is based on the theory of spherical wave expansion of electromagnetic fields, which also establishes a simple criterion for the required number of samples of the power density. An array antenna consisting of Hertzian dipoles is used to test the accuracy and rate of convergence...

  11. 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

    A novel verticall A novel vertically polarized dpolarize , omnidirection omnidirectional l , printed slot loop antenna h sprinted 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...

  12. OPERATION MODES AND CHARACTERISTICS OF PLASMA DIPOLE ANTENNA

    Directory of Open Access Journals (Sweden)

    Nikolay Nikolaevich Bogachev

    2014-02-01

    Full Text Available Existence modes of  surface electromagnetic wave on a plasma cylinder, operating modes and characteristics of the plasma antenna were studied in this paper. Solutions of the dispersion equation of surface wave were obtained for a plasma cylinder with finite radius for different plasma density values. Operation modes of the plasma asymmetric dipole antenna with finite length and radius were researched by numerical simulation. The electric field distributions of  the plasma antenna in near antenna field and the radiation pattern were obtained. These characteristics were compared to characteristics of the similar metal antenna. Numerical models verification was carried out by comparing of the counted and measured metal antenna radiation patterns.

  13. Absorbed Power Minimization in Cellular Users with Circular Antenna Arrays

    Science.gov (United States)

    Christofilakis, Vasilis; Votis, Constantinos; Tatsis, Giorgos; Raptis, Vasilis; Kostarakis, Panos

    2010-01-01

    Nowadays electromagnetic pollution of non ionizing radiation generated by cellular phones concerns millions of people. In this paper the use of circular antenna array as a means of minimizing the absorbed power by cellular phone users is introduced. In particular, the different characteristics of radiation patterns produced by a helical conventional antenna used in mobile phones operating at 900 MHz and those produced by a circular antenna array, hypothetically used in the same mobile phones, are in detail examined. Furthermore, the percentage of decrement of the power absorbed in the head as a function of direction of arrival is estimated for the circular antenna array.

  14. 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.

  15. Compact Ultra-Wideband Antenna for Portable Devices

    International Nuclear Information System (INIS)

    This article presents a compact ultra-wideband (UWB) antenna for wireless dongle devices. The printed monopole antenna, with the size of 15 mm × 30 mm, has an impedance bandwidth ranges from 2.9 to 13 GHz. The proposed structure comprises of a hexagonal radiator fed by a microstrip line with a modified ground plane. Such a design can be easily integrated with wireless universal serial bus (USB) devices. Having stable radiation patterns and constant gain within the UWB spectrum are significant characteristics of this antenna. The time domain studies on the designed antenna indicate reduced ringing effect for impulse excitation across the band of interest.

  16. A Simple Method to Stabilize Radiation Pattern over a Large Bandwidth

    Directory of Open Access Journals (Sweden)

    Haiyang Zhang

    2014-01-01

    Full Text Available An alternative radiation stabilization method has been presented for patch antenna. With this method, side radiation could be suppressed when a conductor ring and a circular slot both with the width of a quarter-wavelength are placed on the same layer and around patch antenna. An experimental structure has been simulated and the distance l from antenna part to conductor ring is optimized using parametric function of HFSS software. Measured results given in this paper obviously indicate that not only the side radiation from the boundary of substrate could be suppressed effectively, but also the antenna directivity could be adjusted and enhanced after this method has been carried out. Both simulation and measurement indicate that when the distance l is set to one guided wavelength (λg, side radiation could be suppressed the most effectively and the return loss of patch antenna is only slightly affected.

  17. A novel variable-distance antenna test range and high spatial resolution corroboration of the inverse square law for 433.5 MHz radiation

    CERN Document Server

    de Haën, Christoph; Erhardt, Matthias

    2015-01-01

    A novel, low-budget, open-air, slant-geometry antenna test range for UHF radiation is presented. It was designed primarily to facilitate variation of the distance between emitter and receiver antennas, but has also the potential for adaptation to simultaneous variation of distance and receiver antenna orientation. In support of the validity of the range the inverse square law for 433.5 MHz radiation between two naked half-wave dipole antennas was tested with high spatial resolution from close to the far field limit outward to 46 wavelengths. Sine amplitude input voltage at the receiver antenna varied with the distance to the power -0.9970 +/- 0.0051 (R^2 = 0.992), thus corroborating the inverse square law for transmission power at the lowest frequency for which thus far data have been published. Keywords: inverse square law; dipole antenna; test facility; electromagnetic propagation; UHF measurements; distance dependence.

  18. Cross-Slot Antenna with U-Shaped Tuning Stub for Ultra-Wideband Applications

    Directory of Open Access Journals (Sweden)

    Dawood Seyed Javan

    2008-01-01

    Full Text Available A novel design of an ultra-wideband (UWB slot antenna is presented. This antenna operates as a transmitter and receiver antenna. Effects of the antenna dimensional parameters are studied through experimental and simulation results. Design procedures are developed and verified for different frequency bands. The experimental and simulation results exhibit good impedance bandwidth, radiation pattern, and relatively constant gain over the entire band of frequency. Antenna gain and directivity at boresight and in their maximum states are close to each other and indicate high radiation efficiency. To use the antenna as a linearly polarized antenna, the radiation pattern in E-plane is better than that in H-plane.

  19. Using Antenna Arrays to Motivate the Study of Sinusoids

    Science.gov (United States)

    Becker, J. P.

    2010-01-01

    Educational activities involving antenna arrays to motivate the study of sinusoids are described. Specifically, using fundamental concepts related to phase and simple geometric arguments, students are asked to predict the location of interference nulls in the radiation pattern of two-element phased array antennas. The location of the radiation…

  20. 47 CFR 73.685 - Transmitter location and antenna system.

    Science.gov (United States)

    2010-10-01

    ... RADIO BROADCAST SERVICES Television Broadcast Stations § 73.685 Transmitter location and antenna system... “blanket areas” of television broadcast stations. A “blanket area” is that area adjacent to a transmitter... corrective action. (e) An antenna designed or altered to produce a noncircular radiation pattern in...

  1. Small Device For Short-Range Antenna Measurements Using Optics

    DEFF Research Database (Denmark)

    Yanakiev, Boyan Radkov; Nielsen, Jesper Ødum; Christensen, Morten;

    2011-01-01

    This paper gives a practical solution for implementing an antenna radiation pattern measurement device using optical fibers. It is suitable for anechoic chambers as well as short range channel sounding. The device is optimized for small size and provides a cheap and easy way to make optical antenna...

  2. Cage-shaped Wideband Antenna Based on Folded Monopoles

    OpenAIRE

    Morlaas, Christophe; Souny, Bernard; Chabory, Alexandre

    2014-01-01

    A new antenna structure based on a disk-loaded folded monopole antenna is presented. Its VSWR performances are equivalents to those of the Goubau antenna for similar dimensions. The radiation pattern is monopole-like on the full bandwidth (one octave) and the manufacturing is very easy. The operation analysis based on a basic loaded folded monopole is presented and validated from a full-wave simulation tool.

  3. Band-width performances of antennas based on leaky lens radiation

    NARCIS (Netherlands)

    Neto, A.; Bruniy, S.; Gerini, G.; Sabbadini, M.; Marliani, F.

    2005-01-01

    Leaky lens antennas are linearly polarised antennas constituted by long slots etched on a ground plane that separates a dense dielectric, shaped as a lens, from free space. Three different versions of the same antenna concept exist: multi-frequency, wide band, ultra-wide band. In all cases these ant

  4. Jacobi-Bessel Analysis Of Antennas With Elliptical Apertures.

    Science.gov (United States)

    Rahmat-Samii, Y.

    1989-01-01

    Coordinate transformation improves convergence pattern analysis of elliptical-aperture antennas. Modified version of Jacobi-Bessel expansion for vector diffraction analysis of reflector antennas uses coordinate transformation to improve convergence with elliptical apertures. Expansion converges rapidly for antennas with circular apertures, but less rapidly for elliptical apertures. Difference in convergence behavior between circular and elliptical Jacobi-Bessel algorithms indicated by highest values of indices m, n, and p required to achieve same accuracy in computed radiation pattern of offset paraboloidal antenna with elliptical aperture.

  5. A True Metasurface Antenna

    OpenAIRE

    Mohamed El Badawe; Almoneef, Thamer S.; Omar M. Ramahi

    2016-01-01

    We present a true metasurface antenna based on electrically-small resonators. The resonators are placed on a flat surface and connected to one feed point using corporate feed. Unlike conventional array antennas where the distance between adjacent antennas is half wavelength to reduce mutual coupling between adjacent antennas, here the distance between the radiating elements is electrically very small to affect good impedance matching of each resonator to its feed. A metasurface antenna measur...

  6. Omnidirectional Antenna with Multi-Resonance Performance for Microwave Imaging Systems

    Directory of Open Access Journals (Sweden)

    N. Ojaroudi

    2013-11-01

    Full Text Available In this paper, a novel ultra-wideband printed monopole antenna (PMA for microwave imaging systems is presented. The proposed antenna provides a wide usable fractional bandwidth of more than 160% (2.12-17.87 GHz. The antenna has an ordinary square radiating patch, therefore displays a good omni-directional radiation pattern even at higher frequencies and also its radiation efficiency is greater than 82% across the entire radiating band. The designed antenna has a small size of 12×18 mm2.

  7. Statistical analysis of electromagnetic radiation measurements in the vicinity of GSM/UMTS base station antenna masts.

    Science.gov (United States)

    Koprivica, Mladen; Neskovic, Natasa; Neskovic, Aleksandar; Paunovic, George

    2014-01-01

    As a result of dense installations of public mobile base station, additional electromagnetic radiation occurs in the living environment. In order to determine the level of radio-frequency radiation generated by base stations, extensive electromagnetic field strength measurements were carried out for 664 base station locations. Base station locations were classified into three categories: indoor, masts and locations with installations on buildings. Having in mind the large percentage (47 %) of sites with antenna masts, a detailed analysis of this location category was performed, and the measurement results were presented. It was concluded that the total electric field strength in the vicinity of base station antenna masts in no case exceeded 10 V m(-1), which is quite below the International Commission on Non-Ionizing Radiation Protection reference levels. At horizontal distances >50 m from the mast bottom, the median and maximum values were <1 and 2 V m(-1), respectively.

  8. A Small UWB Antenna with Dual Band-Notched Characteristics

    Directory of Open Access Journals (Sweden)

    J. Xu

    2012-01-01

    Full Text Available A small novel ultrawideband (UWB antenna with dual band-notched functions is proposed. The dual band rejection is achieved by etching two C-shaped slots on the radiation patch with limited area. A single band-notched antenna is firstly presented, and then an optimized dual band-notched antenna is presented and analyzed. The measured VSWR shows that the proposed antenna could operate from 3.05 to 10.7 GHz with VSWR less than 2, except two stopbands at 3.38 to 3.82 GHz and 5.3 to 5.8 GHz for filtering the WiMAX and WLAN signals. Radiation patterns are simulated by HFSS and verified by CST, and quasiomnidirectional radiation patterns in the H-plane could be observed. Moreover, the proposed antenna has a very compact size and could be easily integrated into portable UWB devices.

  9. A new photonic bandgap cover for a patch antenna with a photonic bandgap substrate

    Institute of Scientific and Technical Information of China (English)

    林青春; 朱方明; 何赛灵

    2004-01-01

    A new photonic bandgap (PBG) cover for a patch antenna with a photonic bandgap substrate is introduced. The plane wave expansion method and the FDTD method were used to calculate such an antenna system. Numerical results for the input return loss, radiation pattern, surface wave, and the directivity of the antennas are presented. A comparison between the conventional patch antenna and the new PBG antenna is given. It is shown that the new PBG cover is very efficient for improving the radiation directivity. The physical reasons for the improvement are also given.

  10. Enhanced terahertz radiation from an elliptical-beam-illuminated sawtooth photoconductive antenna: design and numerical analysis

    CERN Document Server

    Zhang, Jitao

    2014-01-01

    The enhanced terahertz radiation from a new photoconductive antenna (PCA) has been predicted by numerical simulation. Different from the conventional PCA, the proposed PCA has electrodes with sawtooth structures on the edge, which will introduce stronger localized bias field than common electrode (e.g. strip-line structure). In addition, the elliptical beam of the laser source is used to illuminate the sawtooth structure of the PCA, so that the effective region of the terahertz excitation is enlarged and higher laser power can be applied before saturation effect occurs. The design of the proposed PCA is presented, and its performance is predicated by numerical analysis based on the full-wave finite-difference-time-domain method. The simulated result shows that, comparing with a conventional PCA, the proposed PCA achieves $1.4$ times enhancement of the THz radiation field(i.e. peak of the time-domain THz pulse) at the same condition. Further enhancement as high as $2$ times can be achieved when considering the...

  11. Study of the surface and far fields of terahertz radiation generated by large-aperture photoconductive antennas

    Institute of Scientific and Technical Information of China (English)

    Zhang Tong-Yi; Cao Jun-Cheng

    2004-01-01

    We have studied analytically the temporal characteristics of terahertz radiation emitted from a biased largeaperture photoconductive antenna triggered by an ultrashort optical pulse. We have included the effects of the finite lifetime and transient mobility dynamics of photogenerated carriers in the analysis. Succinct explicit expressions are obtained for the emitted radiation in the surface field and in the far field. The dependence of the waveforms of the radiated field on the fluence and duration of triggering optical pulse, carrier relaxation time and carrier lifetime are discussed in detail using the obtained expressions.

  12. Development of leaky-wave antenna for digitally controlled millimeter-wave interferometer.

    Science.gov (United States)

    Kogi, Yuichiro; Yoshikawa, Masayuki; Matsukawa, Shingo; Mase, Atsushi; Nagayama, Yoshio; Kawahata, Kazuo

    2012-10-01

    We propose a new interferometer concept that can realize electron-density distribution measurement with high spatial and moderate temporal resolution. The image non-radiative dielectric guide antenna can probe a wide measurement area simultaneously. We fabricated the antenna with an electromagnetic simulator and confirmed that the simulated and measured radiation patterns are consistent with each other. In addition, we found that the antenna shows the required characteristics such as scanning characteristics, which depend on the input frequency.

  13. Development of leaky-wave antenna for digitally controlled millimeter-wave interferometer.

    Science.gov (United States)

    Kogi, Yuichiro; Yoshikawa, Masayuki; Matsukawa, Shingo; Mase, Atsushi; Nagayama, Yoshio; Kawahata, Kazuo

    2012-10-01

    We propose a new interferometer concept that can realize electron-density distribution measurement with high spatial and moderate temporal resolution. The image non-radiative dielectric guide antenna can probe a wide measurement area simultaneously. We fabricated the antenna with an electromagnetic simulator and confirmed that the simulated and measured radiation patterns are consistent with each other. In addition, we found that the antenna shows the required characteristics such as scanning characteristics, which depend on the input frequency. PMID:23127004

  14. Efficiency of a Compact Elliptical Planar Ultra-Wideband Antenna Based on Conductive Polymers

    OpenAIRE

    Christophe Fumeaux; Roderick Shepherd; Bo Weng; Akhilesh Verma; Van-Tan Truong; Thomas Kaufmann

    2012-01-01

    A planar antenna for ultra-wideband (UWB) applications covering the 3.1–10.6 GHz range has been designed as a test bed for efficiency measurements of antennas manufactured using polymer conductors. Two types of conductive polymers, PEDOT and PPy (polypyrrole), with very different thicknesses and conductivities have been selected as conductors for the radiating elements. A comparison between measured radiation patterns of the conductive polymers and a copper reference antenna allows to estimat...

  15. Frequency Reconfigurable Hybrid Slot Antenna Using PIN Diodes

    Science.gov (United States)

    Yang, Xiaolin; Sheng, Lili; Lin, Jiancheng; Chen, Gang

    2015-11-01

    This paper introduces a frequency reconfigurable hybrid slot antenna fed by coplanar waveguide (CPW) without complex bias network and DC blocking capacitor chips. In order to add reconfigurablility to the antenna, the PIN diodes are equipped in the slots. The antenna is capable of frequency switching at six different frequency bands between 1.7 GHz to 2.5 GHz, which can be used in multiradio wireless systems, such as DCS-1800, PCS1900, UMTS, Wibro and Bluetooth bands. The simulated and measured return loss, peak gain, together with the radiation patterns are presented and compared. Especially, the radiation patterns are stable at different frequency.

  16. Experimental investigation of a mm-wave planar antenna

    Science.gov (United States)

    Lambrakakis, Georgios D.

    1990-06-01

    This thesis investigates a new mm-wave Bilateral Slot Line (BSL) antenna and its relation to the Linearly Tapered Slot Antenna (LTSA). The BSL antenna consists of a tapered double-sided slotline and can be viewed as two identical LTSAs sandwiched back to back. Dielectric substrates with permittivities of 2.33 and 6.0 were used to construct these antennas. The theoretical background, the design, and the performance in the frequency range 5 to 9 GHz of the new microwave integrated circuit antenna is presented. The effects of several parameters such as dielectric constant, stripline and slotline characteristic impedance, antenna structure, and transition scheme on the radiation patterns and return loss were experimentally investigated. Some relationships between the width of stripline and slotline, their characteristic impedance and the dielectric constant are reported. Guidelines are laid to design the LTSA and BSL antennas.

  17. Characteristics of Planar Monopole Antenna on High Impedance Electromagnetic Surface

    Science.gov (United States)

    Scardelletti, Maximilian C.; Jastram, Nathan; Ponchak, George E.; Franklin, Rhonda R.

    2011-01-01

    This paper presents for the first time measured characteristics of a planar monopole antenna placed directly on a high impedance electromagnetic surface or artificial magnetic conductor (AMC). The return loss and radiation patterns are compared between the antenna in free space, and when placed directly on a perfect electrical conductor (PEC), and on the AMC. The antenna measured in free space has a wide pass band from 3 to 10 GHz. The return loss for the antenna on the PEC is nearly all reflected back and the return loss for the antenna on the AMC has a 10 dB bandwidth from 7.5 to 9.5 GHz. The gain of the antenna in free space, on PEC and on AMC is 1, -12 and 10 dBi, respectively. This indicates that the AMC is working properly, sending all the radiation outward with little loss.

  18. Fabrication of Slot-Antenna Coupled Warm Carrier Detectors for Submillimeter Wave Radiation

    Science.gov (United States)

    Yasuoka, Yoshizumi; Shimizu, Takashi; Abe, Yasuhiko; Kirihata, Atsushi; Gamo, Kenji

    1999-09-01

    Thin-film slot-antenna-coupled edge-type warm carrier devices with a contact area of about 8×10-10 cm2 were fabricated, and their detection properties were investigated at 700 GHz. The fabricated slot antenna operates as a one-wavelength slot antenna as designed on the basis of the experimental results obtained in the microwave region. In addition, the fabricated edge-type warm carrier device operates as a detector, and rectifies the 700 GHz signal received by the antenna. The sensitivity of the device at 700 GHz was about 100 V/W.

  19. 基于特异材料微带漏波天线辐射特性研究%Investigation of Radiation Characteristics for Metamaterial Microstrip Leaky-Wave Antennas

    Institute of Scientific and Technical Information of China (English)

    吴瑞坤

    2011-01-01

    The radiation principles of the metamaterial composite right/left-handed microstrip leaky wave antennas are analyzed in this paper, the simulation model of the metamaterial composite right/left- handed microstrip leaky-wave antenna is established and the radiation characteristics of the microstrip leaky- wave antenna are obtained by calculating the simulation results.The antenna has the same parameters with the simulation model is designed.The S parameters and the pattern of the antenna and the capacitive transient voltage of each unit are measured.Finally, the good agreement is obtained by the comparative simulation results and experimental results.At a fixed frequency, when the composite right / left handed metamaterials microstrip leaky-wave antenna operates in the left handed region, the electromagnetic wave radiated mainly in the first few units of the antenna, and it decayed rapid exponentially, when it operates in the right handed region, the electromagnetic wave radiated along the antenna and attenuate slowly.%分析复合左右手特异材料微带漏波天线的辐射原理,建立复合左右手材料微带漏波天线仿真模型,通过仿真计算得到微带漏波天线的辐射特性.制备与仿真参数相同的实物天线,测量天线S参数、方向图和天线各单元电容瞬态电压.最后,对仿真试验结果和实物天线测量结果比较,吻合较好.在固定工作频率下,复合左右手特异材料微带漏波天线工作在左手区时,电磁波辐射主要发生在天线结构前几个单元,且电磁波以指数形式快速衰减,工作在右手区时,电磁波沿整个天线辐射,且电磁波衰减较慢.

  20. 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.

  1. Design of a New Model of Multiband Miniature Antenna Near Isotropic

    Directory of Open Access Journals (Sweden)

    Abdellatif Berkat

    2011-11-01

    Full Text Available In this paper, we propose a new slotted multiband antennas simulated at different frequencies. The insertion of slots in the patch gives a good adapting frequency with various forms on the radiation pattern. The main feature of the proposed antenna is the capability to generate a near isotropic radiation pattern in different frequencies .The design details of the conceived antenna are presented and discussed. Simulations of the different reflection coefficient and radiation pattern are presented. These were carried out using CST Microwave Studio. This model has got numerous applications in network sensors, field measurements and electromagnetic compatibility.

  2. Curved spiral antennas for underwater biological applications

    Science.gov (United States)

    Llamas, Ruben

    We developed curved spiral antennas for use in underwater (freshwater) communications. Specifically, these antennas will be integrated in so-called mussel backpacks. Backpacks are compact electronics that incorporate sensors and a small radio that operate around 300 MHz. Researchers attach these backpacks in their freshwater mussel related research. The antennas must be small, lightweight, and form-fit the mussel. Additionally, since the mussel orientation is unknown, the antennas must have broad radiation patterns. Further, the electromagnetic environment changes significantly as the mussels burrow into the river bottom. Broadband antennas, such a spiral antennas, will perform better in this instance. While spiral antennas are well established, there has been little work on their performance in freshwater. Additionally, there has been some work on curved spiral antennas, but this work focused on curving in one dimension, namely curving around a cylinder. In this thesis we develop spiral antennas that curve in two dimensions in order to conform the contour of a mussel's shell. Our research has three components, namely (a) an investigation of the relevant theoretical underpinning of spiral antennas, (b) extensive computer simulations using state-of-the art computational electromagnetics (CEM) simulation software, and (c) experimental validation. The experimental validation was performed in a large tank in a laboratory setting. We also validated some designs in a pool (~300,000 liters of water and ~410 squared-meter dive pool) with the aid of a certified diver. To use CEM software and perform successful antenna-related experiments require careful attention to many details. The mathematical description of radiation from an antenna, antenna input impedance and so on, is inherently complex. Engineers often make simplifying assumptions such as assuming no reflections, or an isotropic propagation environment, or operation in the antenna far field, and so on. This makes

  3. Numerical Calculation of Electric Fields in Housing Spaces due to Electromagnetic Radiation from Antennas for Mobile Communication

    Directory of Open Access Journals (Sweden)

    H.-P. Geromiller

    2004-01-01

    Full Text Available The influence of electromagnetic radiation from mobile antennas on humans is under discussion in various group of scientists. This paper deals with the impact of electromagnetic radiation in housing spaces. The space is assumed to be bordered by 5 walls of ferroconcrete and a door-window combination on the 6th side, the latter to be electromagnetic transparent. The transparent side of the housing is exposed to an electromagnetic wave. As the source of radiation is considered to be far away from the housing, the radiation is regarded as a plane wave. Due to the high signal frequency and the ferroconcrete walls, 5 sides of the housing space are considered to be perfect conductors. The electric field inside the housing is calculated numerically by the method of finite differences for different angles of incidence of the radiated electromagnetic wave. The maximum value of the calculated electric field is outlined in a diagram.

  4. Antenna design and characterization based on the elementary antenna concept

    Science.gov (United States)

    Ligthart, L. P.

    An antenna-design technique based on an elementary-antenna model (an infinitesimal pillbox structure carrying electric and magnetic currents and containing propagating TEM fields) is developed and demonstrated. An EM description of a waveguide aperture is obtained by applying approximate boundary conditions at specific points; the transmitted field is developed locally into a set of TEM field components to compute the radiation pattern; and aperture matching is achieved by calculating the aperture reflection as well. Parallel-plate, circular, and rectangular waveguides; two single-polarization TEM waveguide radiators (with and without dielectric filling); a dielectric-filled dual-polarization TE(01) waveguide radiator; and a hybrid reflector array with limited beam switching based on the TE(01) radiator are presented.

  5. 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....

  6. Wideband Reconfigurable Rolled Planar Monopole Antenna

    OpenAIRE

    Ruvio, Giuseppe; Ammann, Max

    2007-01-01

    A novel technique to reconfigure the frequency range of a planar monopole antenna is presented. By adjusting the degree of spiral tightness, a shift of the well-matched operating frequency range is achieved. The proposed antenna is capable of covering the frequencies in the range from 2.9 to 15 GHz, depending on the degree of spiral tightness. The antenna yields a high-efficiency across the full operating bandwidth. Radiation patterns show good omni-directional features in all primary cuts an...

  7. Modal radiation patterns of baffled circular plates and membranes

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain;

    2014-01-01

    The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation...... circular radiator....

  8. Measurement of Radiation Frequency of Gyrotron by GaAs Schottky Barrier Diodes Coupled with Thin-Film Slot Antenna

    Science.gov (United States)

    Kosuke Hayashi,; Takashi Furuya,; Takashi Tachiki,; Takashi Uchida,; Toshitaka Idehara,; Yoshizumi Yasuoka,

    2010-03-01

    Thin-film slot-antenna-coupled GaAs Schottky barrier diodes (SBDs) used at the 180 GHz band were fabricated by microfabrication techniques, and the radiation frequency of a gyrotron at the University of Fukui (Gyrotron FU CW IV) was measured. In second-harmonic mixing using a local oscillator (LO) wave of 88.0899 GHz, an intermediate frequency (IF) signal of 102.8 MHz was observed and the radiation frequency of the gyrotron was found to be 176.077 GHz.

  9. Controlling terahertz radiation with nanoscale metal barriers embedded in nano slot antennas.

    Science.gov (United States)

    Park, Hyeong-Ryeol; Bahk, Young-Mi; Ahn, Kwang Jun; Park, Q-Han; Kim, Dai-Sik; Martín-Moreno, Luis; García-Vidal, Francisco J; Bravo-Abad, Jorge

    2011-10-25

    Nanoscale metallic barriers embedded in terahertz (THz) slot antennas are shown to provide unprecedented control of the transition state arising at the crossover between the full- and half-wavelength resonant modes of such antennas. We demonstrate strong near-field coupling between two paired THz slot antennas separated by a 5 nm wide nanobarrier, almost fully inducing the shift to the resonance of the double-length slot antenna. This increases by a factor of 50 the length-scale needed to observe similar coupling strengths in conventional air-gap antennas (around 0.1 nm), making the transition state readily accessible to experiment. Our measurements are in good agreement with a quantitative theoretical modeling, which also provides a simple physical picture of our observations. PMID:21961910

  10. Slot Antenna Coupled YBa2Cu3O7-δ Josephson Mixers for Millimeter Wave Radiation

    Science.gov (United States)

    Hasegawa, Akihisa; Uchida, Takashi; Yasuoka, Yoshizumi

    1999-12-01

    The antenna structure and the direction of the irradiated signal wave were investigated in order to improve the responsivity of a slot antenna coupled YBa2Cu3O7-δ (YBCO) Josephson mixer. The slot antenna coupled Josephson mixer consists of a thin-film slot antenna on a fused quartz substrate and a YBCO Josephson junction on a MgO substrate. It was found that maximum responsivity was obtained by letting the thickness of the MgO substrate be odd multiples of λd/4 (λd: wavelength in the substrate) and irradiating the electromagnetic wave through the MgO substrate. Furthermore, the device with the optimized structure improved the responsivity in the third-harmonic mixing by 7 dB compared to the device without a slot antenna in the harmonicmixing at 48 GHz.

  11. A Multiband Frequency Reconfigurable Rotated-L Slot Antenna

    Directory of Open Access Journals (Sweden)

    Pardeep Kumar

    2015-06-01

    Full Text Available A multiband frequency reconfigurable rotated-L slot antenna is presented. The antenna is switchable between 4.61-6.20 GHz at nine different frequencies and capable to operates multi frequency at a time. The proposed antenna has a microstrip patch and two rotated-L slots, one slot is at patch and other is at ground plane. The two p-i-n diode is used in the ground plane rotated-L slot to achieve multi frequency agility. Results such as return losses, radiation patterns, gain and bandwidth are used to demonstrate the performance of the proposed antenna.

  12. Low SAR planar antenna for multi standard cellular phones

    OpenAIRE

    Ben Ahmed, M.; Bouhorma, M.; Elouaai, F.; Mamouni, A.

    2011-01-01

    Abstract In this paper the design of a multiband compact antenna for the integration into the new multi function mobile phones is presented. The antenna is matched to operate at GSM 920 MHz, WI-Fi 2.4 GHz and HiperLan 5.1 GHz standards with low SAR levels. Return loss coefficient and radiation pattern of this antenna are computed in free space as well as in the presence of head. The specific absorption rate (SAR) of the planar antenna is calculated and compa...

  13. Fast Adaptive Beamforming with Smart Antenna for Radio Frequency Repeater

    Directory of Open Access Journals (Sweden)

    Wang Chaoqun

    2016-01-01

    Full Text Available We present a fast adaptive beamforming null algorithm with smart antenna for Radio Frequency Repeater (RFR. The smart antenna system is realized by a Direction Of Arrival (DOA Estimator, whose output is used by an adaptive beamforming algorithm to shape a suitable radiation pattern of the equivalent antenna; so that the co-channel interference due to retransmitting antenna can be reduced. The proposed adaptive beamforming algorithm, which has been proved by formulaic analysis and simulation, has a lower computation complexity yet better performance.

  14. A Modified E Shaped Patch Antenna For Mimo Systems

    Directory of Open Access Journals (Sweden)

    K. Jagadeesh Babu

    2010-10-01

    Full Text Available A compact E shaped patch antenna is proposed in the present work, which can be used for Multiple Input Multiple output (MIMO systems. The modified E shaped patch antenna proposed in this paper offers improved directivity, bandwidth, and return loss characteristics compared to normal E shaped antenna. The antenna system resonates at 5.36GHz and 5.89GHz frequencies for VSWR≤2 which can be used for WiMAX (Wireless interoperability for microwave access applications. The simulation results of return loss, VSWR, gain and radiation pattern are presented.

  15. Directivity pattern of the sound radiated from axisymmetric stepped plates.

    Science.gov (United States)

    He, Xiping; Yan, Xiuli; Li, Na

    2016-08-01

    For the purpose of optimal design and efficient utilization of the kind of stepped plate radiator in air, in this contribution, an approach for calculation of the directivity pattern of the sound radiated from a stepped plate in flexural vibration with a free edge is developed based on Kirchhoff-Love hypothesis and Rayleigh integral principle. Experimental tests of directivity pattern for a fabricated flat plate and two fabricated plates with one and two step radiators were carried out. It shows that the configuration of the measured directivity patterns by the proposed analytic approach is similar to those of the calculated approach. Comparison of the agreement between the calculated directivity pattern of a stepped plate and its corresponding theoretical piston show that the former radiator is equivalent to the latter, and the diffraction field generated by the unbaffled upper surface may be small. It also shows that the directivity pattern of a stepped radiator is independent of the metallic material but dependent on the thickness of base plate and resonant frequency. The thicker the thickness of base plate, the more directive the radiation is. The proposed analytic approach in this work may be adopted for any other plates with multi-steps. PMID:27586764

  16. Radiation regression patterns after cobalt plaque insertion for retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Buys, R.J.; Abramson, D.H.; Ellsworth, R.M.; Haik, B.

    1983-08-01

    An analysis of 31 eyes of 30 patients who had been treated with cobalt plaques for retinoblastoma disclosed that a type I radiation regression pattern developed in 15 patients; type II, in one patient, and type III, in five patients. Nine patients had a regression pattern characterized by complete destruction of the tumor, the surrounding choroid, and all of the vessels in the area into which the plaque was inserted. This resulting white scar, corresponding to the sclerae only, was classified as a type IV radiation regression pattern. There was no evidence of tumor recurrence in patients with type IV regression patterns, with an average follow-up of 6.5 years, after receiving cobalt plaque therapy. Twenty-nine of these 30 patients had been unsuccessfully treated with at least one other modality (ie, light coagulation, cryotherapy, external beam radiation, or chemotherapy).

  17. Radiation regression patterns after cobalt plaque insertion for retinoblastoma

    International Nuclear Information System (INIS)

    An analysis of 31 eyes of 30 patients who had been treated with cobalt plaques for retinoblastoma disclosed that a type I radiation regression pattern developed in 15 patients; type II, in one patient, and type III, in five patients. Nine patients had a regression pattern characterized by complete destruction of the tumor, the surrounding choroid, and all of the vessels in the area into which the plaque was inserted. This resulting white scar, corresponding to the sclerae only, was classified as a type IV radiation regression pattern. There was no evidence of tumor recurrence in patients with type IV regression patterns, with an average follow-up of 6.5 years, after receiving cobalt plaque therapy. Twenty-nine of these 30 patients had been unsuccessfully treated with at least one other modality (ie, light coagulation, cryotherapy, external beam radiation, or chemotherapy)

  18. The spherical helical antenna

    OpenAIRE

    Cardoso, J. Christopher

    1992-01-01

    The spherical helical antenna is investigated as a new variation of the conventional helical antenna. The spherical helix is a wire antenna in a helix shape that is wound over a spherical surface instead of the standard cylindrical one. Analysis of this structure requires numerical methods and experimental measurements because its complex geometry makes it very difficult to develop analytic expressions for its radiation characteristics. The wire antenna code ESP, based on the method of ...

  19. Wide Coverage Antennas

    OpenAIRE

    Zackrisson, Jan

    2007-01-01

    Small satellites require small and lightweight antennas for telemetry and command function as well as for downlinking of data. We have during the last thirty years developed a large suite of wide coverage antennas. The basic radiator designs used are quadrifilar helices, waveguides, horns and patch excited cups (PEC) depending on frequency range, coverage requirements and application. The antenna designs range from L-band up to Ka-band frequencies. Typical coverages for the antennas are from ...

  20. Transcriptome and Expression Patterns of Chemosensory Genes in Antennae of the Parasitoid Wasp Chouioia cunea.

    Directory of Open Access Journals (Sweden)

    Yanni Zhao

    Full Text Available Chouioia cunea Yang is an endoparasitic wasp that attacks pupae of Hyphantria cunea (Drury, an invasive moth species that severely damages forests in China. Chemosensory systems of insects are used to detect volatile chemical odors such as female sex pheromones and host plant volatiles. The antennae of parasite wasps are important for host detection and other sensory-mediated behaviors. We identified and documented differential expression profiles of chemoreception genes in C. cunea antennae. A total of 25 OBPs, 80 ORs, 10 IRs, 11 CSP, 1 SNMPs, and 17 GRs were annotated from adult male and female C. cunea antennal transcriptomes. The expression profiles of 25 OBPs, 16 ORs, and 17 GRs, 5 CSP, 5 IRs and 1 SNMP were determined by RT-PCR and RT-qPCR for the antenna, head, thorax, and abdomen of male and female C. cunea. A total of 8 OBPs, 14 ORs, and 8 GRs, 1 CSP, 4 IRs and 1 SNMPs were exclusively or primarily expressed in female antennae. These female antennal-specific or dominant expression profiles may assist in locating suitable host and oviposition sites. These genes will provide useful targets for advanced study of their biological functions.

  1. Transcriptome and Expression Patterns of Chemosensory Genes in Antennae of the Parasitoid Wasp Chouioia cunea.

    Science.gov (United States)

    Zhao, Yanni; Wang, Fengzhu; Zhang, Xinyue; Zhang, Suhua; Guo, Shilong; Zhu, Gengping; Liu, Qiang; Li, Min

    2016-01-01

    Chouioia cunea Yang is an endoparasitic wasp that attacks pupae of Hyphantria cunea (Drury), an invasive moth species that severely damages forests in China. Chemosensory systems of insects are used to detect volatile chemical odors such as female sex pheromones and host plant volatiles. The antennae of parasite wasps are important for host detection and other sensory-mediated behaviors. We identified and documented differential expression profiles of chemoreception genes in C. cunea antennae. A total of 25 OBPs, 80 ORs, 10 IRs, 11 CSP, 1 SNMPs, and 17 GRs were annotated from adult male and female C. cunea antennal transcriptomes. The expression profiles of 25 OBPs, 16 ORs, and 17 GRs, 5 CSP, 5 IRs and 1 SNMP were determined by RT-PCR and RT-qPCR for the antenna, head, thorax, and abdomen of male and female C. cunea. A total of 8 OBPs, 14 ORs, and 8 GRs, 1 CSP, 4 IRs and 1 SNMPs were exclusively or primarily expressed in female antennae. These female antennal-specific or dominant expression profiles may assist in locating suitable host and oviposition sites. These genes will provide useful targets for advanced study of their biological functions. PMID:26841106

  2. Amplitude pattern synthesis for conformal array antennas using mean-field neural networks

    NARCIS (Netherlands)

    Castaldi, G.; Gerini, G.

    2001-01-01

    In this paper, we deal with the synthesis problem of conformai array antennas using a mean-field neural network. We applied a discrete version of mean-field neural network proposed by Vidyasagar [1], This technique is used to find the global minimum of the objective function, which represents the sq

  3. Designing Adaptive Linear Array Antenna to Achieve Pattern Steering Optimization by Phase-Amplitude Perturbations Using Genetic Algorithms

    Institute of Scientific and Technical Information of China (English)

    HSUChaohsing; CHENTsongyi; PanJengshyang

    2005-01-01

    In this paper, a phase-amplitude perturbation method of an adaptive array factor based on the genetic algorithm is proposed. The design for an optimal beam pattern of an adaptive antenna is able to not only suppress interference by placing nulls at the directions of the interfering sources but also provide a maximized main lobe in the direction of the desired signal, i.e., to maximizethe Signal interference ratio (SIR). In order to achieve this goal, a kind of new convergent skill called the two-way convergent method for genetic algorithms is proposed. The phase-amplitude perturbation method is applied to realize the optimal beam pattern of an adaptively linear array antenna. The Genetic algorithms are applied to find the optimal phase-amplitude weighting vector of adaptive array factor. An optimal beam pattern of linear array is derived by phase-amplitude perturbations using a genetic algorithm. Computer simulation result is given to demonstrate the effectiveness of the proposed method.

  4. Body-Worn Spiral Monopole Antenna for On-Body Communications (Invited Paper)

    DEFF Research Database (Denmark)

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

    2015-01-01

    A novel body-worn spiral monopole antenna is presented. The antenna consists of a ground plane and a spiral monopole. The antenna was designed for Ear-to-Ear (E2E) communication between In-the-Ear (ITE) hearing instruments at 2.45 GHz and has been simulated, prototyped, and measured. The antenna ...... yielded a measured and simulated E2E path gain at 2.45 GHz of –82.1 dB and –85.9 dB, respectively. The radiation pattern of the antenna when mounted in the ear is presented and discussed....

  5. Body-Worn Spiral Monopole Antenna for On-Body Communications (Invited Paper)

    OpenAIRE

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2015-01-01

    A novel body-worn spiral monopole antenna is presented. The antenna consists of a ground plane and a spiral monopole. The antenna was designed for Ear-to-Ear (E2E) communication between In-the-Ear (ITE) hearing instruments at 2.45 GHz and has been simulated, prototyped, and measured. The antenna yielded a measured and simulated E2E path gain at 2.45 GHz of –82.1 dB and –85.9 dB, respectively. The radiation pattern of the antenna when mounted in the ear is presented and discussed.

  6. Body-Worn Spiral Monopole Antenna for Body-Centric Communications.

    OpenAIRE

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

    2015-01-01

    A novel body-worn spiral monopole antenna is presented. The antenna consists of a ground plane and a spiral monopole. The antenna is designed for Ear-to-Ear (E2E) communication between In-the-Ear (ITE) Hearing Instruments (HIs) at 2.45 GHz and has been simulated, prototyped and measured. The antenna yields a measured and simulated Ear-to-Ear path gain at 2.45 GHz of -82.1 dB and -85.9 dB, respectively. The radiation pattern of the antenna when mounted in the ear is presented and discussed.

  7. Identification of Abnormal System Noise Temperature Patterns in Deep Space Network Antennas Using Neural Network Trained Fuzzy Logic

    Science.gov (United States)

    Lu, Thomas; Pham, Timothy; Liao, Jason

    2011-01-01

    This paper presents the development of a fuzzy logic function trained by an artificial neural network to classify the system noise temperature (SNT) of antennas in the NASA Deep Space Network (DSN). The SNT data were classified into normal, marginal, and abnormal classes. The irregular SNT pattern was further correlated with link margin and weather data. A reasonably good correlation is detected among high SNT, low link margin and the effect of bad weather; however we also saw some unexpected non-correlations which merit further study in the future.

  8. Reconfigurable Plasma Antenna Array by Using Fluorescent Tube for Wi-Fi Application

    Directory of Open Access Journals (Sweden)

    H. Ja’afar

    2016-06-01

    Full Text Available This paper presents a new design of reconfigurable plasma antenna array using commercial fluorescent tube. A round shape reconfigurable plasma antenna array is proposed to collimate beam radiated by an omnidirectional antenna (monopole antenna operates at 2.4GHz in particular direction. The antenna design is consisted of monopole antenna located at the center of circular aluminum ground. The monopole antenna is surrounded by a cylindrical shell of conducting plasma. The plasma shield consists of 12 commercial fluorescent tubes aligned in series containing a mixture of Argon gas and mercury vapor which upon electrification forms plasma columns. The plasma behaves as a conductor and acts as a reflector in radiation, in the condition where plasma frequency,ωp is higher than operating frequency. From this concepts, when all plasma elements are activated or switched to ON, the radiation signal from monopole antenna will trapped inside the plasma blanket and meanwhile when one or more plasma elements is deactivated (switched OFF, the radiation from monopole antenna will escape. This antenna has the capability to change its patterns with beam direction at 0°, 30°, 60°, 90°, 120°, 150°, 180°, 210°, 240°, 270°, 300° and 330° at frequency 2.4 GHz. The proposed antenna has been successfully fabricated and measured with conclusive results.

  9. Single and dual-Gregorian reflector antenna shaped beam far-field synthesis

    Science.gov (United States)

    Mehler, M. J.

    The direct far-field G.O. synthesis of shaped beam reflector antennas has recently been treated by Mehler, Tun and Adatia (1986). These authors use a synthesis technique which exploits complex coordinates and which is based on a method originally considered by Norris and Westcott (1976). They describe the synthesis of single reflector antennas which radiate both elliptical beams and European coverage patterns. Here this technique is extended to consider a class of dual reflector antennas which possess shaped main reflectors and conic subreflectors. An example is given of a Gregorian duel reflector antenna which radiates a cross-polar field significantly smaller than that radiated by single shaped reflector antennas. In addition, the behavior of the radiation pattern as a function of the reflector diameter is investigated.

  10. Bandwidth optimization of compact microstrip antenna for PCS/DCS/bluetooth application

    Science.gov (United States)

    Singh, Vinod; Ali, Zakir; Ayub, Shahanaz; Singh, Ashutosh

    2014-09-01

    A novel compact broadband microstrip patch antenna is presented for various wireless applications. The proposed antenna has been fabricated and the impedance bandwidth and radiation pattern are measured. The simulated and measured antenna characteristics along with radiation pattern and gain are presented. It is stated that the proposed designed antenna can completely cover the required band widths of Digital communication system (DCS 1.71-1.88 GHz), Personal communication system (PCS 1.85-1.88 GHz) and IEEE 802.11b/g (2.4-2.485 GHz) with satisfactory radiation characteristics. The Experimental result shows that the proposed antenna presents a bandwidth 60.25% covering the range of 1.431-2.665 GHz with the maximum radiation efficiency 90%.

  11. 基于外场场强测量的短波天线辐射效率监测%Monitoring of Short-wave Antenna Radiation Efficiency Based on Outfield Measurement

    Institute of Scientific and Technical Information of China (English)

    赵鹏; 陈斌; 杨路刚

    2015-01-01

    Aiming at the problem of too many difficulties to monitor the radiation efficiency of short-wave antennas on site,a method based on outfield measurement of field strength to monitor the short-wave antennas'radiation efficiency was researched.This method combined technologies of antenna modeling and measurement,solved and analyzed the potential-type dyadic Green's function of medium half space by the domain-transformation method.The RWG Method of Moment (RWG-MoM)was adopted to discrete the Mixed Potential Integral Equation (MPIE)in formulation C of planar multi-lay-ered media,and the relative distribution of short-wave antenna radiation power was obtained.The outfield antenna radiation field strength was measured to get the real density of electromagnetic power,which was made as the sample to estimate the antenna radiation power,and the radiation efficiency was calculated by the ratio of the radiation power and the input power. And then,taking short-wave dipole antenna as example,the measurement of field strength in far field was conducted by air-ship field strength measuring platform,and the normalized radiation patterns obtained in experiments were in good agree-ment with simulation.The radiation efficiency calculated by this method coincided well with published papers',and the moni-toring of short-wave antennas'radiation efficiency was achieved.%针对短波天线辐射效率难以现场监测的问题,研究一种基于外场场强测量的短波天线辐射效率监测方法。该方法结合天线仿真与测量技术,通过域变换法解析介质半空间位型并矢格林函数,采用RWG 矩量法(RWG-MoM)离散平面分层介质 C 类混合位电场积分方程(MPIE),得到天线辐射功率的相对分布。测量天线外场场强,得到场点电磁功率面密度作为样本估计天线辐射功率,由辐射功率与输入功率的比值计算得到天线辐射效率。以短波双极天线为例,基于现有的飞艇场强测量平台,

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

    Science.gov (United States)

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

    2016-03-01

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

  13. Analysis and Design of Tapered Slot Antenna for Ultra-Wideband Applications

    Institute of Scientific and Technical Information of China (English)

    YAO Yuan; CHEN Wenhua; HUANG Bin; FENG Zhenghe; ZHANG Zhijun

    2009-01-01

    The tapered slot antenna,such as Vivaldi,has been widely used due to its ultra-wideband,high gain,simple feed structure,and easy fabrication.However,there is no rigorous analytical theory for this type of antenna.This paper analyzed the metal parts of a tapered slot antenna in a conical coordinate system with the medium analyzed in rectangular coordinates.This mixed mode gave an approximate analytical form for the tapered slot antenna with the field distribution and radiation characteristics.A planar tapered slot antenna was proposed according to the results of the analysis methods.Measured and simulated results demonstrate the antenna performance.The antenna shows good impedance matching over a wide bandwidth of 9 GHz,from 2 GHz to 11 GHz,and good radiation patterns.It is suitable for ultra-wideband applications.

  14. Design and development of a small compact ultra wideband antenna

    International Nuclear Information System (INIS)

    In this paper the design of a novel and compact U slot UWB printed monopole microstrip antenna of size 19.2 × 28.8 mm2 has been presented for wireless applications. The planar, small and thin UWB antenna design consists of a U slot radiator fed by a single 50Ω microstrip line with truncated ground plane is excited by a coaxial SMA connector. The simulations are done using the Ansoft High Frequency Structure Simulator (HFSS) software tool. The simulated results of impedance bandwidth are well supported by measurement. The measured group delay and radiation pattern results are also presented and performance of the antenna is analyzed/discussed.

  15. Metamaterial Inspired Microstrip Antenna Investigations Using Metascreens

    Directory of Open Access Journals (Sweden)

    Muhammad Tauseef Asim

    2015-01-01

    Full Text Available A dual layer periodically patterned metamaterial inspired antenna on a low cost FR4 substrate is designed, simulated, fabricated, and tested. The eigenmode dispersion simulations are performed indicating the left handed metamaterial characteristics and are tunable with substrate permittivity. The same metamaterial unit cell structure is utilized to fabricate a metascreen. This metascreen is applied below the proposed metamaterial antenna and next used as superstrate above a simple patch to study the effects on impedance bandwidth, gain, and radiation patterns. The experimental results of these antennas are very good and closely match with the simulations. More importantly, the resonance for the proposed metamaterial antenna with metascreen occurs at the left handed (LH eigenfrequency of the metamaterial unit cell structure. The measured −10 dB bandwidths are 14.56% and 22.86% for the metamaterial antenna with single and double metascreens, respectively. The metascreens over the simple patch show adjacent dual band response. The first and second bands have measured −10 dB bandwidths of 9.6% and 16.66%. The simulated peak gain and radiation efficiency are 1.83 dBi and 74%, respectively. The radiation patterns are also very good and could be useful in the UWB wireless applications.

  16. Miniaturization of UWB Antennas on Organic Material

    Directory of Open Access Journals (Sweden)

    Symeon Nikolaou

    2016-01-01

    Full Text Available Three planar, CPW-fed, UWB antennas with increasingly reduced size are presented and the miniaturization method is discussed. The first antenna is a CPW-fed elliptical slot with an uneven U-shaped tuning stub, the second antenna is a cactus shaped monopole, and the third one is a miniaturized version of the cactus shaped monopole antenna. All presented antennas have a simulated and measured return loss below −10 dB over the 3.1 to 10.6 GHz UWB frequency range and mostly omnidirectional radiation patterns. The proposed antennas are fabricated on liquid crystal polymer (LCP. The CPW-fed slot antenna requires an overall board dimension of 38 mm × 40 mm, and the evolved cactus monopole is confined in a 28 mm × 32 mm board, while the final miniaturized cactus monopole is printed on 28 mm × 20 mm board, resulting in a 41% and 63% size reduction, respectively. Using both simulations and measurements, the paper analyzes the response of all three antennas and discusses and demonstrates the effectiveness of the implemented miniaturization method.

  17. Switched-beam array of dielectric rod antenna with RF-MEMS switch for millimeter-wave applications

    Science.gov (United States)

    Rousstia, M. W.; Reniers, A. C. F.; Herben, M. H. A. J.

    2015-03-01

    A conformal dielectric rod antenna array with operating frequency of 11.2 GHz is investigated, designed, and measured. This antenna array is combined with a single pole double throw radio frequency microelectromechanical systems (RF-MEMS) switch to realize switched-beam performance. Moreover, this antenna array exhibits uniform radiation performance for different scan angles with no grating lobes. The characterization and measurement of the antenna system have been performed. The measured radiation pattern of the antenna in the anechoic chamber is in good agreement with the simulated antenna pattern. The measured antenna with the RF-MEMS switch has 13.5 dBi realized gain, -15 dB sidelobe level, 22° half-power beamwidth, and 7.3% (fractional) bandwidth (or 800 MHz) at 11.2 GHz.

  18. A new planar feed for slot spiral antennas

    Science.gov (United States)

    Nurnberger, M. W.; Volakis, J. L.

    1995-01-01

    This report presents a new planar, wideband feed network for a slot spiral antenna, and the subsequent design and performance of a VHF antenna utilizing this feed design. Both input impedance and radiation pattern measurements are presented to demonstrate the performance and usefulness of this feed. Almost all previous designs have utilized wire spirals, requiring bulky, non-planar feeds with separate baluns, and large absorbing cavities. The presented slot spiral antenna feed integrates the balun into the structure of the slot spiral antenna, making the antenna and feed planar. This greatly simplifies the design and construction of the antenna, in addition to providing repeatable accuracy. It also allows the use of a very shallow reflecting cavity for conformal applications. Finally, this feeding approach now makes many of the known miniaturization techniques viable options.

  19. Low SAR planar antenna for multi standard cellular phones

    Science.gov (United States)

    Ben Ahmed, M.; Bouhorma, M.; Elouaai, F.; Mamouni, A.

    2011-03-01

    In this paper the design of a multiband compact antenna for the integration into the new multi function mobile phones is presented. The antenna is matched to operate at GSM 920 MHz, WI-Fi 2.4 GHz and HiperLan 5.1 GHz standards with low SAR levels. Return loss coefficient and radiation pattern of this antenna are computed in free space as well as in the presence of head. The specific absorption rate (SAR) of the planar antenna is calculated and compared with that of the monopole antenna. To examine the performance of this antenna, a prototype was designed, fabricated and measured; the simulation analysis was performed using the HFSS software, good agreement with the simulation providing validation of the design procedure.

  20. A 3D printed helical antenna with integrated lens

    KAUST Repository

    Farooqui, Muhammad Fahad

    2015-10-26

    A novel antenna configuration comprising a helical antenna with an integrated lens is demonstrated in this work. The antenna is manufactured by a unique combination of 3D printing of plastic material (ABS) and inkjet printing of silver nano-particle based metallic ink. The integration of lens enhances the gain by around 7 dB giving a peak gain of about 16.4 dBi at 9.4 GHz. The helical antenna operates in the end-fire mode and radiates a left-hand circularly polarized (LHCP) pattern. The 3-dB axial ratio (AR) bandwidth of the antenna with lens is 3.2 %. Due to integration of lens and fully printed processing, this antenna configuration offers high gain performance and requires low cost for manufacturing.

  1. An Ultrawideband Monopole Fractal Antenna with Coplanar Waveguide Feed

    Directory of Open Access Journals (Sweden)

    Muhammad Naeem Iqbal

    2014-01-01

    Full Text Available A novel ultrawideband fractal antenna in monopole configuration is proposed. Wideband behavior and miniaturization is achieved using concentric heptagonal array structure. Coplanar waveguide is used to feed fractal antenna. Base shape for fractal antenna is heptagonal geometry. Final fractal shape is achieved by performing four base shape iterations. FR4 substrate is used for antenna fabrication. Simulated and measured results comparison shows a bandwidth of 7 GHz with 9 GHz center frequency. Radiation pattern of monopole fractal antenna is omni directional. Fundamental purpose of designing and fabricating UWB fractal antenna is its application in body area networks for remote patient health monitoring. Its application also includes C and X band frequencies.

  2. Compact Low Frequency Radio Antenna

    Science.gov (United States)

    Punnoose, Ratish J.

    2008-11-11

    An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

  3. Ultrawideband method of feeding a dipole antenna

    OpenAIRE

    Bakhrakh, Lev D.; Los', V. F.; Shamanov, A. N.

    2003-01-01

    An antenna-feeder device is considered, in which a new way of antenna excitation is implemented. An example is presented of its use with a dipole antenna for the radiation of super-short pulse signals.

  4. CPW Fed Tapered Slot Antenna at 5.5 GHz for Wireless Applications

    Directory of Open Access Journals (Sweden)

    Dr.T.SHANMUGANANTHAM

    2010-11-01

    Full Text Available In this paper is to give a novel approach in the design and development of Coplanar Waveguide fed tapered slot antenna for various 5 to 6 GHZ frequency band applications. The fundamental parameters of the antenna such as bandwidth, return loss, gain, radiation pattern and polarization are obtained. All meets theacceptable antenna standards. The measured input impedance bandwidth (return loss >10 dB of the prototype antenna is 21% (4.8–6 GHz. The radiation patterns are bidirectional in the E-plane and H-plane. The simulated peak antenna gain is 3.1 dBi. Procedure to improve the peak gain is also presented. Simulation tool, based on the method of moments (ZELAND IE3D version 12.0 has been used to analyze and optimize the antenna.

  5. Patterns Antennas Arrays Synthesis Based on Adaptive Particle Swarm Optimization and Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Boufeldja Kadri

    2013-01-01

    Full Text Available In recent years, evolutionary optimization (EO techniques have attracted considerable attention in the design of electromagnetic systems of increasing complexity. This paper presents a comparison between two optimization algorithms for the synthesis of uniform linear and planar antennas arrays, the first one is an adaptive particle swarm optimization (APSO where the inertia weight and acceleration coefficient are adjusted dynamically according to feedback taken from particles best memories to overcome the limitations of the standard PSO which are: premature convergence, low searching accuracy and iterative inefficiency. The second method is the genetic algorithms (GA inspired from the processes of the evolution of the species and the natural genetics. The results show that the design of uniform linear and planar antennas arrays using APSO method provides a low side lobe level and achieve faster convergence speed to the optimum solution than those obtained by a GA.

  6. Annular Planar Monopole Antennas

    OpenAIRE

    Chen, Z. N.; Ammann, Max; Chia, W.Y. W.; See, T.S. P.

    2002-01-01

    A type of annular planar monopole antenna is presented. The impedance and radiation characteristics of the monopole with different holes and feed gaps are experimentally examined. The measured results demonstrate that the proposed antenna is capable of providing significantly broad impedance bandwidth with acceptable radiation performance.

  7. Pattern-recognition techniques applied to performance monitoring of the DSS 13 34-meter antenna control assembly

    Science.gov (United States)

    Mellstrom, J. A.; Smyth, P.

    1991-01-01

    The results of applying pattern recognition techniques to diagnose fault conditions in the pointing system of one of the Deep Space network's large antennas, the DSS 13 34-meter structure, are discussed. A previous article described an experiment whereby a neural network technique was used to identify fault classes by using data obtained from a simulation model of the Deep Space Network (DSN) 70-meter antenna system. Described here is the extension of these classification techniques to the analysis of real data from the field. The general architecture and philosophy of an autonomous monitoring paradigm is described and classification results are discussed and analyzed in this context. Key features of this approach include a probabilistic time-varying context model, the effective integration of signal processing and system identification techniques with pattern recognition algorithms, and the ability to calibrate the system given limited amounts of training data. Reported here are recognition accuracies in the 97 to 98 percent range for the particular fault classes included in the experiments.

  8. Design Analysis of An Electromagnetic Band Gap Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    M. S. Alam

    2011-01-01

    Full Text Available Problem statement: Wideband compact antenna is highly demandable due to the dynamic development in the wireless technology. Approach: A simple, compact EBG microstrip antenna is proposed in this study that covers a wideband of 250 GHz and the design is conformal with the 2.45 GHz ISM band (WLAN, IEEE 802.11b and g/Bluetooth/RFID applications. Results: A 6×6 array of square unit cell formed the EBG structure which is incorporated with the radiating patch to enhance the antenna performances. This design achieved an impedance bandwidth of 10.14% (2.34-2.59 GHz at -10 dB return loss and VSWR ≤ 2. Simulated radiation pattern is almost omnideirectional. Conclusion/Recommendations: The simulated results prove the compatibility of the EBG antenna with the 2.45 GHz ISM band applications. Further enhancement of the antenna performance with improved design is under consideration.

  9. A linearly and circularly polarized active integrated antenna

    Science.gov (United States)

    Khoshniat, Ali

    This thesis work presents a new harmonic suppression technique for microstrip patch antennas. Harmonic suppression in active integrated antennas is known as an effective method to improve the efficiency of amplifiers in transmitter side. In the proposed design, the antenna works as the radiating element and, at the same time, as the tuning load for the amplifier circuit that is directly matched to the antenna. The proposed active antenna architecture is easy to fabricate and is symmetric, so it can be conveniently mass-produced and designed to have circular polarization, which is preferred in many applications such as satellite communications. The antenna simulations were performed using Ansoft High Frequency System Simulator (HFSS) and all amplifier design steps were simulated by Advanced Design System (ADS). The final prototypes of the linearly polarized active integrated antenna and the circularly polarized active integrated antenna were fabricated using a circuit board milling machine. The antenna radiation pattern was measured inside Utah State University's anechoic chamber and the results were satisfactory. Power measurements for the amplifiers' performance were carried out inside the chamber and calculated by using the Friis transmission equation. It is seen that a significant improvement in the efficiency is achieved compared to the reference antenna without harmonic suppression. Based on the success in the single element active antenna design, the thesis also presents a feasibility of applying the active integrated antenna in array configuration, in particular, in scanning array design to yield a low-profile, low-cost alternative to the parabolic antenna transmitter of satellite communication systems.

  10. Optically controlled reconfigurable antenna for 5G future broadband cellular communication networks

    DEFF Research Database (Denmark)

    da Costa, Igor; Cerqueira Sodre Jr., Arismar; Gustavo da Silva, Luis;

    to higher frequency solutions, such as E-and W-band solutions. We present two key elements for the project: a broadband horn antenna for millimetre-wave and an optically controlled reconfigurable antenna, which can adapt its frequency response and radiation pattern by using photonics technology...

  11. FAILURE CORRECTION OF LINEAR ARRAY ANTENNA WITH MULTIPLE NULL PLACEMENT USING CUCKOO SEARCH ALGORITHM

    OpenAIRE

    Muralidaran, R.; A. Vallavaraj; Hemant Patidar; Mahanti, G. K.

    2014-01-01

    The influence of evolutionary algorithms enhanced its scope of getting its existence in almost every complex optimization problems. In this paper, cuckoo search algorithm, an algorithm based on the brood parasite behavior along with Levy weights has been proposed for the radiation pattern correction of a linear array of isotropic antennas with uniform spacing when failed with more than one antenna element. Even though deterioration produced by the failure of antenna elements results in variou...

  12. Planar textile antennas with artificial magnetic conductor for body-centric communications

    Science.gov (United States)

    Kamardin, Kamilia; Rahim, Mohamad Kamal A.; Hall, Peter S.; Samsuri, Noor Asmawati; Latef, Tarik Abdul; Ullah, Mohammad Habib

    2016-04-01

    Two textile antennas namely diamond dipole and coplanar waveguide (CPW) monopole are designed to test the proposed textile artificial magnetic conductor (AMC). Performance comparison including return loss, radiation pattern, and gain between the two antennas above AMC is observed. Results show gain improvement with reduced backlobes when having AMC. Bending and wetness measurements are also conducted. Bending is found not to cause performance disruption, while wetness influences performance distortion. However, once the antennas and AMC dried out, the original performance is retrieved.

  13. Wideband Planar U-shaped Monopole Antenna with Meandering Technique for TV White Space Application

    OpenAIRE

    Jamaluddin, M. H.; T. A. Rahman; H. Mohamad; Ramli, N; Islam, M. T.

    2013-01-01

    A novel wideband planar U-shaped antenna with meandering technique is proposed for TV White Space operation at 470 -798 MHz band. The antenna consists of a U-shaped antenna backed by a partial ground plane. The meandering technique is applied by inserting several slots at the bottom part of the U-shaped for bandwidth enhancement. An impedance bandwidth of 95.2% is achieved when the planar U-shaped antenna is added with 21 slots. The radiation pattern confirms that a good pattern stability are...

  14. Mobile Handset Performance Evaluation Using Radiation Pattern Measurements

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Pedersen, Gert Frølund

    2006-01-01

    The mean effective gain is an attractive performance measure of mobile handsets, since it incorporates both directional and polarization properties of the handset and environment. In this work the mean effective gain is computed from measured spherical radiation patterns of five different mobile...

  15. Using Radiation Pattern Measurements for Mobile Handset Performance Evaluation

    DEFF Research Database (Denmark)

    Nielsen, Jesper Ødum; Pedersen, Gert Frølund

    2005-01-01

    The mean effective gain (MEG) is an attractive performance measure of mobile handsets, since it incorporates both directional and polarization properties of the handset and environment. In this work the MEG is computed from measured spherical radiation patterns of five different mobile handsets...

  16. On the Remarkable Features of the Lower Limits of Charge and the Radiated Energy of Antennas as Predicted by Classical Electrodynamics

    Directory of Open Access Journals (Sweden)

    Vernon Cooray

    2016-05-01

    Full Text Available Electromagnetic energy radiated by antennas working in both the frequency domain and time domain is studied as a function of the charge associated with the current in the antenna. The frequency domain results, obtained under the assumption of sinusoidal current distribution, show that, for a given charge, the energy radiated within a period of oscillation increases initially with L/λ and then starts to oscillate around a steady value when L/λ > 1. The results show that for the energy radiated by the antenna to be equal to or larger than the energy of one photon, the oscillating charge in the antenna has to be equal to or larger than the electronic charge. That is, U ≥ hν or UT ≥ h ⇒ q ≥ e, where U is the energy dissipated over a period, ν is the frequency of oscillation, T is the period, h is Planck’s constant, q is the rms value of the oscillating charge, and e is the electronic charge. In the case of antennas working in the time domain, it is observed that UΔt ≥ h/4π ⇒ q ≥ e, where U is the total energy radiated, Δt is the time over which the energy is radiated, and q is the charge transported by the current. It is shown that one can recover the time–energy uncertainty principle of quantum mechanics from this time domain result. The results presented in this paper show that when quantum mechanical constraints are applied to the electromagnetic energy radiated by a finite antenna as estimated using the equations of classical electrodynamics, the electronic charge emerges as the smallest unit of free charge in nature.

  17. Bioburden assessment and gamma radiation inactivation patterns in parchment documents

    International Nuclear Information System (INIS)

    Parchment documents are part of our cultural heritage and, as historical artifacts that they are, should be preserved. The aim of this study was to validate an appropriate methodology to characterize the bioburden of parchment documents, and to assess the growth and gamma radiation inactivation patterns of the microbiota present in that material. Another goal was to estimate the minimum gamma radiation dose (Dmin) to be applied for the decontamination of parchment as an alternative treatment to the current toxic chemical and non-chemical decontamination methods. Two bioburden assessment methodologies were evaluated: the Swab Method (SM) and the Destructive Method (DM). The recovery efficiency of each method was estimated by artificial contamination, using a Cladosporium cladosporioides spore suspension. The parchment samples' microbiota was typified using morphological methods and the fungal isolates were identified by ITS-DNA sequencing. The inactivation pattern was assessed using the DM after exposure to different gamma radiation doses, and using C. cladosporioides as reference. Based on the applied methodology, parchment samples presented bioburden values lower than 5×103 CFU/cm2 for total microbiota, and lower than 10 CFU/cm2 for fungal propagules. The results suggest no evident inactivation trend for the natural parchment microbiota, especially regarding the fungal community. A minimum gamma radiation dose (Dmin) of 5 kGy is proposed for the decontamination treatment of parchment. Determining the minimal decontamination dose in parchment is essential for a correct application of gamma radiation as an alternative decontamination treatment for this type of documents avoiding the toxicity and the degradation promoted by the traditional chemical and non-chemical treatments. - Highlights: • Characterization of the microbial population of parchment documents. • Study the inactivation pattern of parchment microbiota by gamma radiation. • Assessment of the

  18. 蝶形天线阵列电磁辐射特性的CBFM分析%Electromagnetic Radiation Characteristics Analysis of Bow-tie Antenna Array Using CBFM

    Institute of Scientific and Technical Information of China (English)

    王国华; 陈治平; 李刚; 段连飞

    2013-01-01

    针对传统矩量法分析天线阵列效率低的问题,给出了一种分析蝶形天线阵列电磁辐射特性的有效数值方法,该方法基于特征基函数法(CBFM )和等效偶极矩法(EDM ),不仅可以加速阻抗矩阵的产生,还可根据特征基函数(CBFs)的阶数和子域的数目调节系数矩阵的维数,从而可以采用直接法求解缩减矩阵方程,与传统矩量法(MoM)相比,显著地减小了运算量。数值结果验证了蝶形天线阵列的方向图并证实了该方法的精确性和有效性。%In view of the problem of low efficiency in analyzing the antenna arrays using the traditional method of moments (MOM),an efficient numerical approach for the electromagnetic radiation characteristics analysis of bow-tie antenna array is presented based on the combination of the characteristic basis function method(CBFM)and the equivalent dipole moment(EDM)method,which can not only accelerate the production of impedance matrix,but also can adjust the size of the coefficient matrix according to the order of CBFs and the number of sub-blocks,thus it is possible to handle the reduced matrix equation by using a direct solution. The computa-tional cost is reduced significantly compared with the traditional MoM. Numerical results validate the radiation pattern of bow-tie antenna array,as well as the efficiency and accuracy of the approach.

  19. Assessment of radiofrequency/microwave radiation emitted by the antennas of rooftop-mounted mobile phone base stations

    International Nuclear Information System (INIS)

    Radiofrequency (RF) and microwave (MW) radiation exposures from the antennas of rooftop-mounted mobile telephone base stations have become a serious issue in recent years due to the rapidly evolving technologies in wireless telecommunication systems. In Malaysia, thousands of mobile telephone base stations have been erected all over the country, most of which are mounted on the rooftops. In view of public concerns, measurements of the RF/MW levels emitted by the base stations were carried out in this study. The values were compared with the exposure limits set by several organisations and countries. Measurements were performed at 200 sites around 47 mobile phone base stations. It was found that the RF/MW radiation from these base stations were well below the maximum exposure limits set by various agencies. (authors)

  20. Investigation of a Novel Compact Microstrip Antenna for Radiotelemetry Capsules Based on FDTD

    Institute of Scientific and Technical Information of China (English)

    HUANG Biao; YAN Guo-zheng; LI Qian-ru

    2007-01-01

    The objective of this paper is to design a microstrip patch antenna for the miniature electro-capsule communicating with external recorder at 915 MHz located in Industry, Science, and Medical (ISM) bands. Microstrip antenna design parameters, resonance characteristics and radiation patterns are evaluated using the finite-difference time-domain (FDTD) method. The effects of location of feed point and human body are analyzed, and the radiation performances of the proposed antenna are estimated in terms of radiation patterns. Finally, specific absorption rate (SAR) computations are also performed, and the peak 1-g and 10-g SAR values are calculated. According to peak SAR values, the maximum delivered, power for the designed antenna was found so that the SAR values of the antennas satisfy ANSI limitations.

  1. Receiving and Detection of Ultra-Wideband Microwave Signals Radiated by Pulsed Excitation of Monopole Antennas

    Directory of Open Access Journals (Sweden)

    Steponas AŠMONTAS

    2014-06-01

    Full Text Available Pulsed excitation of small size monopole antennas for generating wideband electromagnetic pulses was used. The monopoles were excited by electrical pulses having rise times of 600 ps, 200 ps, 70 ps and voltages 100 V, 15 V, and 0.4 V respectively. Antennas spanning (0.3 – 26 GHz bandwidth, including broadband horns with coaxial outputs, were employed to receive signals, which were investigated using (0 – 26 GHz passband sampling oscilloscope. It was found that waveforms of signals, received by the antennas, mostly depend on the pulse rise time and on the details of geometry of monopoles. The electromagnetic pulses have relatively long duration of about 30 ns and spectral harmonics up to 22 GHz. Therefore they can be attributed to pulses with large base. The results show that the upper frequencies of the spectrum most probably are cut off by existing arrangement. Usage of such pulses can find wide practical application when they are received after transmission trough different media by a number of antennas having different operational frequency ranges, followed by digital signal processing. DOI: http://dx.doi.org/10.5755/j01.ms.20.2.6330

  2. Quantum-dot based ultrafast photoconductive antennae for efficient THz radiation

    Science.gov (United States)

    Gorodetsky, Andrei; Bazieva, Natalia; Rafailov, Edik U.

    2016-03-01

    Here we overview our work on quantum dot based THz photoconductive antennae, capable of being pumped at very high optical intensities of higher than 1W optical mean power, i.e. about 50 times higher than the conventional LT-GaAs based antennae. Apart from high thermal tolerance, defect-free GaAs crystal layers in an InAs:GaAs quantum dot structure allow high carrier mobility and ultra-short photo carrier lifetimes simultaneously. Thus, they combine the advantages and lacking the disadvantages of GaAs and LT-GaAs, which are the most popular materials so far, and thus can be used for both CW and pulsed THz generation. By changing quantum dot size, composition, density of dots and number of quantum dot layers, the optoelectronic properties of the overall structure can be set over a reasonable range-compact semiconductor pump lasers that operate at wavelengths in the region of 1.0 μm to 1.3 μm can be used. InAs:GaAs quantum dot-based antennae samples show no saturation in pulsed THz generation for all average pump powers up to 1W focused into 30 μm spot. Generated THz power is super-linearly proportional to laser pump power. The generated THz spectrum depends on antenna design and can cover from 150 GHz up to 1.5 THz.

  3. Density convection near radiating ICRF antennas and its effect on the coupling of lower hybrid waves

    International Nuclear Information System (INIS)

    Combined operation of lower hybrid (LH) and Ion Cyclotron Resonance Frequency (ICRF) waves can result in a degradation of the LH wave coupling, as observed both in the Tore-Supra and Jet tokamaks. The reflection coefficient on the part of the LH launcher magnetically connected to the powered ICRF antenna increases, suggesting a local decrease in the electron density in the connecting flux tubes. This has been confirmed by Langmuir probe measurements on the LH launchers in the latest Tore-Supra experiments. Moreover, recent experiments in Jet indicate that the LH coupling degradation depends on the ICRF power and its launched k/ spectrum. The 2D density distribution around the Tore-Supra ICRF antennas has been modelled with the CELLS-code, balancing parallel losses with diffusive transport and sheath induced ExB convection, obtained from RF field mapping using the ICANT-code. The calculations are in qualitative agreement with the experimental observations, i.e. density depletion is obtained, localised mainly in the antenna shadow, and dependent on ICRF power and antenna spectrum. (authors)

  4. Analysis of antenna-radome systems

    Science.gov (United States)

    Liu, Jianfen; Wan, Wei

    1987-01-01

    The conventional two-dimensional ray-tracing technique is a classical method for analysis of antenna-radome systems. However, in the detailed treatment of field distortions introduced by the radome, the accuracy is usually uncertain due to the inherent errors associated with the ray-tracing approximation of the antenna near field. A very effective approach based on a sampling theorem using the plane-wave spectrum (PWS) method is given in this paper. The effects of an airborne radome on the antenna radiation pattern are analyzed from many aspects. Besides the analysis of regular apparent boresight error, stress is put on the calculations of radome cross-polarization fields and sidelobes (flash lobes) induced by reflection on the inner surface of the radome. A number of useful curves for every variation are shown, and the effects of varying the antenna scanning angle are also discussed.

  5. A curl antenna

    OpenAIRE

    Nakano, Hisamatsu; Okuzawa, Shigeru; Ohishi, Katsumi; Mimaki, Hiroaki; Yamauchi, Junji

    1993-01-01

    A radiation element, designated as a curl antenna, is proposed for a circularly polarized antenna. The radiation characteristics of the curl are numerically analyzed. The gain is approximately 8.4 dB, and the 3-dB axial ratio criterion is 6.7%. Two aspects of curl array antennas are also presented: a decoupling factor between two curls and a circular array antenna consisting of 168 curls. Calculations show how the decoupling factor depends on the relative rotation angle of the two curls. The ...

  6. Standard Dataset of Brightness Temperature Resampled by Antenna Pattern Matching for Microwave Radiometer AMSR2 on GCOM-W1 Satellite

    Science.gov (United States)

    Maeda, Takashi; Imaoka, Keiji

    2014-05-01

    The operation of the Advanced Microwave Scanning Radiometer for Earth-Observation System (AMSR-E) loaded on Aqua satellite stopped in October, 2011 after more than 9-years observation. But after that, the successor of AMSR-E (AMSR2) was developed and loaded on GCOM-W1 (Global Change Observation Mission 1st - Water) satellite. GCOM-W1 satellite was successfully launched in May, 2012. AMSR2 is a microwave radiometer almost similar to AMSR-E, but some important improvements are made (i.e., expansion of its main reflector's size, addition of 7.3-GHz channel to detect radio frequency interferences at 6.9 GHz). GCOM-W1 satellite is deployed into a sun-synchronous sub-recurrent orbit, and AMSR2 observes microwave powers emitted from anywhere on the Earth almost twice a day, daytime in an ascending track and nighttime in a descending track. When we use a satellite-borne microwave radiometer data that have a main reflector shared by plural feed horns, there is an inevitable problem, the differences of footprints' sizes among frequencies. In case of AMSR2, the smallest footprint's size of 89 GHz (3 × 5 km2) has just one percent of the broadest one of 6.9 GHz (35 × 62 km2). Under the circumstance, when brightness temperatures (Tb values) of plural frequencies are obtained from the same geolocation, it is difficult to compare them one another because their observation areas are absolutely different. The concept to solve this problem is simple: actually, after a satellite-borne microwave radiometer observed on the Earth's surface, footprints which give brightness temperatures of each frequency densely distribute on it with overlaps at several-kilometer intervals (i.e., 5 km as for 89 GHz and 10 km as for other frequencies in AMSR2). The footprint is an antenna pattern projected to the Earth's surface. The antenna pattern's shape is generally like a 2-dimensional Gaussian distribution. The center of the antenna pattern has strong sensitivity, and its circumjacent part has weak

  7. Tunable acoustic radiation pattern assisted by effective impedance boundary

    Science.gov (United States)

    Qian, Feng; Quan, Li; Wang, Li-Wei; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2016-02-01

    The acoustic wave propagation from a two-dimensional subwavelength slit surrounded by metal plates decorated with Helmholtz resonators (HRs) is investigated both numerically and experimentally in this work. Owing to the presence of HRs, the effective impedance of metal surface boundary can be manipulated. By optimizing the distribution of HRs, the asymmetric effective impedance boundary will be obtained, which contributes to generating tunable acoustic radiation pattern such as directional acoustic beaming. These dipole-like radiation patterns have high radiation efficiency, no fingerprint of sidelobes, and a wide tunable range of the radiation pattern directivity angle which can be steered by the spatial displacements of HRs. Project supported by the National Basic Research Program of China (Grant Nos. 2012CB921504 and 2011CB707902), the National Natural Science Foundation of China (Grant No.11474160), the Fundamental Research Funds for Central Universities, China (Grant No. 020414380001), the State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLOA201401), the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.

  8. Low profile conformal antenna arrays on high impedance substrate

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents electromagnetic (EM) design and analysis of dipole antenna array over high impedance substrate (HIS). HIS is a preferred substrate for low-profile antenna design, owing to its unique boundary conditions. Such substrates permit radiating elements to be printed on them without any disturbance in the radiation characteristics. Moreover HIS provides improved impedance matching, enhanced bandwidth, and increased broadside directivity owing to total reflection from the reactive surface and high input impedance. This book considers different configurations of HIS for array design on planar and non-planar high-impedance surfaces. Results are presented for cylindrical dipole, printed dipole, and folded dipole over single- and double-layered square-patch-based HIS and dogbone-based HIS. The performance of antenna arrays is analyzed in terms of performance parameters such as return loss and radiation pattern. The design presented shows acceptable return loss and mainlobe gain of radiation pattern. Thi...

  9. Decoupling antennas in printed technology using elliptical metasurface cloaks

    Science.gov (United States)

    M. Bernety, Hossein; Yakovlev, Alexander B.

    2016-01-01

    In this paper, we extend the idea of reducing the electromagnetic interactions between transmitting radiators to the case of widely used planar antennas in printed technology based on the concept of mantle cloaking. Here, we show that how lightweight elliptical metasurface cloaks can be engineered to restore the intrinsic properties of printed antennas with strip inclusions. In order to present the novel approach, we consider two microstrip-fed monopole antennas resonating at slightly different frequencies cloaked by confocal elliptical metasurfaces formed by arrays of sub-wavelength periodic elements, partially embedded in the substrate. The presence of the metasurfaces leads to the drastic suppression of mutual near-field and far-field couplings between the antennas, and thus, their radiation patterns are restored as if they were isolated. Moreover, it is worth noting that this approach is not limited to printed radiators and can be applied to other planar structures as well.

  10. Decoupling antennas in printed technology using elliptical metasurface cloaks

    Energy Technology Data Exchange (ETDEWEB)

    Bernety, Hossein M., E-mail: hmehrpou@go.olemiss.edu, E-mail: yakovlev@olemiss.edu; Yakovlev, Alexander B., E-mail: hmehrpou@go.olemiss.edu, E-mail: yakovlev@olemiss.edu [Center for Applied Electromagnetic Systems Research (CAESR), Department of Electrical Engineering, University of Mississippi, University, Mississippi 38677-1848 (United States)

    2016-01-07

    In this paper, we extend the idea of reducing the electromagnetic interactions between transmitting radiators to the case of widely used planar antennas in printed technology based on the concept of mantle cloaking. Here, we show that how lightweight elliptical metasurface cloaks can be engineered to restore the intrinsic properties of printed antennas with strip inclusions. In order to present the novel approach, we consider two microstrip-fed monopole antennas resonating at slightly different frequencies cloaked by confocal elliptical metasurfaces formed by arrays of sub-wavelength periodic elements, partially embedded in the substrate. The presence of the metasurfaces leads to the drastic suppression of mutual near-field and far-field couplings between the antennas, and thus, their radiation patterns are restored as if they were isolated. Moreover, it is worth noting that this approach is not limited to printed radiators and can be applied to other planar structures as well.

  11. Decoupling antennas in printed technology using elliptical metasurface cloaks

    International Nuclear Information System (INIS)

    In this paper, we extend the idea of reducing the electromagnetic interactions between transmitting radiators to the case of widely used planar antennas in printed technology based on the concept of mantle cloaking. Here, we show that how lightweight elliptical metasurface cloaks can be engineered to restore the intrinsic properties of printed antennas with strip inclusions. In order to present the novel approach, we consider two microstrip-fed monopole antennas resonating at slightly different frequencies cloaked by confocal elliptical metasurfaces formed by arrays of sub-wavelength periodic elements, partially embedded in the substrate. The presence of the metasurfaces leads to the drastic suppression of mutual near-field and far-field couplings between the antennas, and thus, their radiation patterns are restored as if they were isolated. Moreover, it is worth noting that this approach is not limited to printed radiators and can be applied to other planar structures as well

  12. Damage Pattern as a Function of Various Types of Radiation

    Directory of Open Access Journals (Sweden)

    R.G. Ahmed

    2006-01-01

    Full Text Available The number of reports on the effects of various types of radiation is gradually increasing because of weakening of the immune system. Radiation can penetrate into living cells and result in the transfer of radiation energy to the biological material. The absorbed energy can increase the reactive oxygen species and break chemical bonds and cause ionization of different biologically essential macromolecules, such as DNA membrane lipids and proteins. Damage to the cellular membrane release the hydrolytic enzymes responsible for various catabolic processes in the tissues and leads to cell death. An understanding of the pattern in critical cellular structures such as DNA is an important prerequisite for a mechanistic assessment of primary radiation injury. The DNA damage induced by radiation such as base alterations, cross linking, strands breaker chromosomal aberration which may in turn lead to mutations. In order to further explore the harmful effects of radiation. I have produced a variety of effects of radiation on the apoptosis and necrosis. Indeed, the present review has shown that the increase in the oxidative stress (increased endogenous production of the free radicals due to radiation may be a reason for such a damage of the cell membrane, and may lead to harming the cellular elements (such as DNA. Here, one can hypothesize that, the cells with increased sensitivity to oxidative stress may be more susceptible to damage by radiation compared to normal cells. The ultimate biological consequences of this effect are subsequently processed by these cells. Much work remains to be done to firmly establish this concept.

  13. Corner-Fed Microstrip Antenna Analysis for Dual Polarization

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    This paper investigates a corner-fed microstrip patch antenna by means of the cavity model with proposedfeed modeling. The input impedance and radiation patterns for a corner feed are calculated. The mutual coupling be-tween two corner feeds is investigated. An improvement in mutual coupling has been found for corner feeds relativeto edge feeds, which is helpful for the design of dual-polarized antenna arrays in wireless communication and radarapplications

  14. An investigation of planar monopole antennas for modern portable applications

    OpenAIRE

    Evans, Jonathan Arthur, (Thesis)

    2007-01-01

    Current trends in portable and mobile communications are towards greater numbers of different systems often with wider bandwidths, operating within a single device. Antenna systems for these devices need to be capable of operating over a wide frequency range or multiple frequency bands, typically between 900MHz and 6GHz (e.g. GSM, IMT-2000, Wi-Fi and WiMax). Portable and mobile applications also require antennas to be optimised with respect to radiation pattern, efficiency and physical size. ...

  15. 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.

  16. The Far Field Pattern Analysis of Vertical and Horizontal Dipole Embedded in a Dielectric Slab

    OpenAIRE

    G.Anjaneyulu; Dr. G.S.N.Raju

    2014-01-01

    The radiation characteristics of dipole antenna embedded in a dielectric slab depend on dielectric material properties. In this paper, the far field radiation characteristics of vertical and horizontal dipole antennas embedded in a dielectric slab of different thickness with a ground plane is considered and patterns are derived applying reciprocity theorem. Numerical results are presented in a graphical form to show the effects of the dielectric material on antenna pattern

  17. Mutual Coupling Effects Analysis in a Cross-Rhombic Antenna Array

    Directory of Open Access Journals (Sweden)

    Jorge Sosa-Pedroza

    2012-01-01

    Full Text Available We present an analysis of mutual coupling effects on radiation pattern and individual coupling in a conformal array of cross rhombic antennas. Analysis is made using both full-wave simulation and numerical approaches implemented in Matlab. The array consists of a truncated hexagonal pyramid, with a cross rhombic antenna in each pyramidal face, including the one on the top, having a 7-antennas-array. Results of radiation pattern and S11 parameters are presented, showing mutual coupling effects among the elements.

  18. Liquid Crystal Bow-Tie Microstrip antenna for Wireless Communication Applications

    OpenAIRE

    B.T.P.Madhav; VGKM Pisipati; Habibulla Khan; V.G.N.S Prasad; K. Praveen Kumar; KVL Bhavani; M. Ravi Kumar

    2014-01-01

    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 propose...

  19. Ferrite LTCC-based antennas for tunable SoP applications

    KAUST Repository

    Shamim, Atif

    2011-07-01

    For the first time, ferrite low temperature co-fired ceramic (LTCC) tunable antennas are presented. These antennas are frequency tuned by a variable magnetostatic field produced in a winding that is completely embedded inside the ferrite LTCC substrate. Embedded windings have reduced the typically required magnetic bias field for antenna tuning by over 95%. The fact that large electromagnets are not required for tuning makes ferrite LTCC with embedded bias windings an ideal platform for advanced tunable system-on-package applications. Measurements of rectangular microstrip patch antennas on a ferrite LTCC substrate display a maximum tuning range of 610 MHz near 12 GHz. Two different bias windings and their effect on the antenna performance are discussed, as is the effect of antenna orientation with respect to the bias winding. The antenna radiation patterns are measured under biased and unbiased conditions, showing a stable co-polarized linear gain. © 2011-2012 IEEE.

  20. Planar Microstrip Slot Antenna for S and C band Wireless Applications

    International Nuclear Information System (INIS)

    In this paper, compact planar microstrip antennas comprising of broad slots for enhancing various antenna parameters are discussed and presented. The proposed microstrip slot antennas achieved a compactness of maximum 58 % with a peak gain of 7.58 dB. These antennas can be operated for S band applications such as WiMax, operating in the frequency range of 3.3 – 3.6 GHz, RADAR, WLAN, fixed satellite services and maritime mobile services etc. covering 2 – 6 GHz frequency range. The antennas can be used as a compact antenna system where limited size is a foremost requirement. Results also show the satisfactory performance with the dual band frequency characteristics. Details of the antenna design structure, results of return loss (RL), impedance bandwidth and radiation pattern with co-cross polarization are also given.

  1. Model analysis on radiation fields of wire antenna in free space%自由空间导线天线辐射模式分析

    Institute of Scientific and Technical Information of China (English)

    余飞群; 叶尚福

    2012-01-01

    The method of matrix moment adopting piecewise sinusoidal basis func- tions is used to get the current of wire antenna. With the aid of the radiation field expression of piecewise sinusoidal current,the total radiation field of the antenna is obtained through linear superimposition of contribution fields of every piecewise current. The spherical wave expansion is introduced into antenna radiation modal a- nalysis. In addition, numerical integration is adopted to get the spherical wave coef- ficients of antenna radiation field. Using the proposed method, the mode coefficients of dipole, circular loop antenna and helical antenna is obtained, which validates the feasibility of the method.%采用分段正弦基矩量法计算线天线电流,借助分段正弦电流辐射场表达式,将各分段电流产生的辐射场进行线性叠加,进而获得天线总的辐射场。该辐射场利用球面波展开法进行展开,同时采用数值积分方法求取辐射场球面波展开式中各模式的系数值。以3种基本单元天线:偶极子天线、圆环天线以及螺旋天线为例,定量分析了3种基本单元天线的辐射模式,验证了这一方法的正确性。

  2. Compact Microstrip Patch Antenna with Switchable L-Shaped Slots for Wireless Applications

    Directory of Open Access Journals (Sweden)

    Dr.T.SHANMUGANANTHAM

    2010-11-01

    Full Text Available In this paper, analysis and design of compact Microstrip patch antenna incorporated by two orthogonal L-shaped switchable slots is proposed to achieve circular polarization. Two pin diodes are inserted in to these L-shaped slots and by making these two pin diodes ON and OFF the antenna can be radiate with either right handed circular polarization or left handed circular polarization with wide bandwidth. Radiation patterns, return loss and axial ratios are presented. The antenna has an overall dimension of only 18 x 18 mm2 when printed on a substrate of dielectric constant 2.22. A rigorous experimental study has been conducted to confirm the characteristics of the antenna. The experimental results show that the designed antenna can provide excellent performance for Unlicensed & licensed WiMax (IEEE802.16a, future planetary missions and satellite link.Details of the antenna design; experimental and simulated results are presented and discussed.

  3. A Self-Complementary 1.2 to 40 GHz Spiral Antenna with Impedance Matching

    Directory of Open Access Journals (Sweden)

    M. Mazanek

    2006-09-01

    Full Text Available This paper describes a design of the Self- Complementary Spiral Antenna (SCSA which consists of a spiral antenna and a wideband impedance transformer. The spiral antenna and the transformer are designed separately due to computing demands. New knowledge about current distribution on the spiral antenna and influence of higher numbers of wavelength in circumference is presented. The novel transition between feeding and radiating antenna structure are optimized in the frequency range 1.2 to 40 GHz. The meaning of the transition in the paper includes the impedance as well as the geometry transforming of the structure. The antenna is suitable for wideband illuminating of a parabolic reflector due to relatively constant phase center and radiation pattern with frequency.

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

    Science.gov (United States)

    Messiaen, A.; Swain, D.; Ongena, J.; Vervier, M.

    2015-12-01

    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 Vmax amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of Vmax 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// computed by means of the coupling code ANTITER II remains small for the considered cases.

  5. 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, Andre [Ecole Royale Militaire, Brussels Belgium; Swain, David W [ORNL; Ongena, Jef [Ecole Royale Militaire, Brussels Belgium; Vervier, Michael [Ecole Royale Militaire, Brussels Belgium

    2015-01-01

    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-max amplitude of the feeding lines, (ii) the best toroidal phasing control is done by the adjustment of the mean phase of V-max of each poloidal straps column, (iii) with well adjusted system the largest strap current phasing error is +/- 20 degrees, (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//computed by means of the coupling code ANTITER II remains small for the considered cases. [GRAPHICS] .

  6. 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.

  7. Computation of high-resolution SAR distributions in a head due to a radiating dipole antenna representing a hand-held mobile phone

    NARCIS (Netherlands)

    Van de Kamer, JB; Lagendijk, JJW

    2002-01-01

    SAR distributions in a healthy female adult head as a result of a radiating vertical dipole antenna (frequency 915 MHz) representing a hand-field mobile phone have been computed for three different resolutions: 2 mm, 1 mm and 0.4 mm. The extremely high resolution of 0.4 mm was obtained with our quas

  8. 47 CFR 74.641 - Antenna systems.

    Science.gov (United States)

    2010-10-01

    ..., AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Television Broadcast Auxiliary... transmitted signal. Booster station antennas having narrower beamwidths and reduced sidelobe radiation may be... or with the minimum antenna gain requirement; and (B) With the minimum radiation suppression to...

  9. Measure system for the antenna to get the patterns of the tested antennas based on LabVIEW%基于LabVIEW的天线方向图测试系统设计

    Institute of Scientific and Technical Information of China (English)

    刘瑾; 王化吉

    2011-01-01

    针对传统的天线方向图测量方法效率低、精度差的缺点,基于LabVIEW软件平台开发了1套天线方向图自动测试系统.该系统通过GPIB总线实现对测试仪器的控制,在信号录取、角度录取、数据处理、方向图绘制方面实现了完全自动化,具有精度高、测量速度快、性能稳定的特点.%The conventional antenna pattern testing method has the quality of low velocity and low accuracy. Using the software of LabVIEW,we construct the auto-measure system for the antenna to get the patterns of the tested antennas.The system controls instruments by GPIB, and the signal extraction, angle extraction, data processing and pattern plotting are automatic. The system has the quality of high accuracy,high testing velocity and high reliability.

  10. Ladder Arrangement Method for Stealth Design of Vivaldi Antenna Array

    Directory of Open Access Journals (Sweden)

    XiaoXiang He

    2013-01-01

    Full Text Available A novel stealth design method for X-band Vivaldi antenna arrays is proposed in this paper by ladder arrangement along radiation direction. Two-element array, eight-element array, and 3 × 7-element array are investigated in this paper. S parameters, RCSs, and radiation patterns are studied, respectively. According to the ladder arrangement of Vivaldi antennas presented, 16.3 dBsm maximal RCS reduction is achieved with satisfied radiation performance. As simulated and measured, results demonstrate that the effectiveness of the presented low RCS design method is validated.

  11. Rhombic Split Ring Resonator (R-SRR Structure on Rectangular Patch Antenna Design

    Directory of Open Access Journals (Sweden)

    H. Nornikman

    2013-01-01

    Full Text Available This work focusing on the effect of the complementary rhombic split ring resonator (R-SRR structure of gain, return loss and the radiation pattern the rectangular patch antenna design. The basic rectangular patch antenna design had been simulated in CST Microwave Studio simulation software. Then, the single unit of the R-SRR had been added into the patch antenna design. The targeting frequency of this antenna is 2.40 GHz for Wireless Local Area Network (WLAN application. Compared with the conventional microstrip patch antenna with the same aperture size, the performance gain of the patch antennas is improved obviously and suitable for targeting frequency of 2.40 GHz. The parametric studies done this work work are the different variation pattern of R-SRR, different distance between two RSRR structure and different size of R-SRR.

  12. Research on novel multi-layer and multi-polarized slot-coupling planar antenna array

    Institute of Scientific and Technical Information of China (English)

    Zhang Hou; Wu Wenzhou; Wang Jian

    2009-01-01

    A novel multi-layer planar antenna array to achieve multi-polarized radiation is developed. U-shaped coupling slots are embedded in the ground plane to extend the bandwidth. The phase relation between adjacent elements in the radiation field is analyzed when adjacent elements are fed in opposite phase. Return loss and radiation pattern are measured for a 16-element antenna array at 12.5 GHz. The radiation pattern shows a good agreement with the calculated one in the shape of the main beam. The return-loss of the proposed antenna array is less than -20 dB in the 12.5 GHz frequency band (12.25-12.75 GHz). Because of two feed ports the antenna can transmit arbitrary elliptic polarized waves if the two feed ports have different amplitude and phase. The main factors such as element spacing, substrate medium and manufacturing imperfection are analyzed and the corresponding conclusions are presented.

  13. Analysis and Design of Leaky-Wave Antenna with Low SLL Based on Half-Mode SIW Structure

    Directory of Open Access Journals (Sweden)

    Jiaying Guo

    2015-01-01

    Full Text Available This paper presents a novel leaky-wave antenna based on the Half-Mode Substrate Integrated Waveguide (HMSIW structure with low side lobe level. The effect of the structural parameters of the LWAs on the radiation performances is studied. Using beam-forming technique, the leakage loss factor α along the radiation aperture is designed in a tapered way by controlling the aperture depth along the structure. This controls the radiated power along the antenna aperture and finally achieves the radiation pattern with low SLL. Furthermore, the antenna structure is optimized to get an even lower SLL.

  14. Design and construction of CPW fed circular microstrip patch antennas

    Science.gov (United States)

    Vyas, Kirti; Singhal, P. K.; Sharma, A. K.; Pal, Manisha

    2013-01-01

    In this paper, we present feeding approaches of coplanar waveguide fed (CPW) circular microstrip patch antennas, with and without defected ground structure (DGS)`. The antenna feeding impedance is proposed as 50 ohms, built over FR4, a high dielectric constant substrate to obtain broad impedance bandwidth along with stability of the radiation patterns. The antenna with defected ground structure is designed to have band-notched characteristics at 3.5 GHz (for Wi-MAX band-3.3 to 3.7 GHz), at 8.2 GHz (for ITU band-8.025 GHz to 8.4 GHz) so as to avoid interference from these. The FR4 is used as dielectric with value of dielectric loss tangent constant as 0.002 and relative permittivity with 4.4. After applying DGS in ground of the proposed antenna there were improvements concerning bandwidth, and also a small increase in gain was noticed. These antennas are of small sizes with dimensions; 30 mm X 43 mm X 1.6 mm, cheap, compact and easy to fabricate, and achieve good radiation characteristics with higher return loss. This first antenna can have wide application in a great variety of wireless communication and second can operate well as UWB antenna with band notched characteristics. The performance of two antennas is compared in respect to gain, VSWR, return loss and impedance matching.

  15. Omni-directional L-band antenna for mobile communications

    Science.gov (United States)

    Kim, C. S.; Moldovan, N.; Kijesky, J.

    1988-05-01

    The principle and design of an L-band omni-directional mobile communication antenna are discussed. The antenna is a circular wave guide aperture with hybrid circuits attached to higher order mode excitation. It produces polarized and symmetric two split beams in elevation. The circular waveguide is fed by eight probes with a 90 degree phase shift between their inputs. Radiation pattern characteristics are controlled by adjusting the aperture diameter and mode excitation. This antenna satisfies gain requirements as well as withstanding the harsh environment.

  16. A Compact Dual Band Dielectric Resonator Antenna For Wireless Applications

    Directory of Open Access Journals (Sweden)

    A. Gharsallah

    2013-06-01

    Full Text Available This paper presents the design of a dual band rectangular Dielectric Resonator Antenna (DRAcoupled to narrow slot aperture that is fed by microstrip line. The fundamental TE111mode andhigher-order TE113mode are excited with their resonant frequencies respectively. Thesefrequencies can be controlled by changing the DRA dimensions. A dielectric resonator with highpermittivity is used to miniaturize the global structure. The proposed antenna is designed to havedual band operation suitable for both DCS (1710 - 1880 MHz and WLAN (2400 - 2484 MHzapplications. The return loss, radiation pattern and gain of the proposed antenna are evaluated.Reasonable agreement between simulation and experimental results is obtained.

  17. Sensing Urban Patterns with Antenna Mappings: The Case of Santiago, Chile.

    Science.gov (United States)

    Graells-Garrido, Eduardo; Peredo, Oscar; García, José

    2016-01-01

    Mobile data has allowed us to sense urban dynamics at scales and granularities not known before, helping urban planners to cope with urban growth. A frequently used kind of dataset are Call Detail Records (CDR), used by telecommunication operators for billing purposes. Being an already extracted and processed dataset, it is inexpensive and reliable. A common assumption with respect to geography when working with CDR data is that the position of a device is the same as the Base Transceiver Station (BTS) it is connected to. Because the city is divided into a square grid, or by coverage zones approximated by Voronoi tessellations, CDR network events are assigned to corresponding areas according to BTS position. This geolocation may suffer from non negligible error in almost all cases. In this paper we propose "Antenna Virtual Placement" (AVP), a method to geolocate mobile devices according to their connections to BTS, based on decoupling antennas from its corresponding BTS according to its physical configuration (height, downtilt, and azimuth). We use AVP applied to CDR data as input for two different tasks: first, from an individual perspective, what places are meaningful for them? And second, from a global perspective, how to cluster city areas to understand land use using floating population flows? For both tasks we propose methods that complement or improve prior work in the literature. Our proposed methods are simple, yet not trivial, and work with daily CDR data from the biggest telecommunication operator in Chile. We evaluate them in Santiago, the capital of Chile, with data from working days from June 2015. We find that: (1) AVP improves city coverage of CDR data by geolocating devices to more city areas than using standard methods; (2) we find important places (home and work) for a 10% of the sample using just daily information, and recreate the population distribution as well as commuting trips; (3) the daily rhythms of floating population allow to cluster

  18. Sensing Urban Patterns with Antenna Mappings: The Case of Santiago, Chile †

    Science.gov (United States)

    Graells-Garrido, Eduardo; Peredo, Oscar; García, José

    2016-01-01

    Mobile data has allowed us to sense urban dynamics at scales and granularities not known before, helping urban planners to cope with urban growth. A frequently used kind of dataset are Call Detail Records (CDR), used by telecommunication operators for billing purposes. Being an already extracted and processed dataset, it is inexpensive and reliable. A common assumption with respect to geography when working with CDR data is that the position of a device is the same as the Base Transceiver Station (BTS) it is connected to. Because the city is divided into a square grid, or by coverage zones approximated by Voronoi tessellations, CDR network events are assigned to corresponding areas according to BTS position. This geolocation may suffer from non negligible error in almost all cases. In this paper we propose “Antenna Virtual Placement” (AVP), a method to geolocate mobile devices according to their connections to BTS, based on decoupling antennas from its corresponding BTS according to its physical configuration (height, downtilt, and azimuth). We use AVP applied to CDR data as input for two different tasks: first, from an individual perspective, what places are meaningful for them? And second, from a global perspective, how to cluster city areas to understand land use using floating population flows? For both tasks we propose methods that complement or improve prior work in the literature. Our proposed methods are simple, yet not trivial, and work with daily CDR data from the biggest telecommunication operator in Chile. We evaluate them in Santiago, the capital of Chile, with data from working days from June 2015. We find that: (1) AVP improves city coverage of CDR data by geolocating devices to more city areas than using standard methods; (2) we find important places (home and work) for a 10% of the sample using just daily information, and recreate the population distribution as well as commuting trips; (3) the daily rhythms of floating population allow to

  19. Design of RFID tag antenna with integrated solar cell as antenna radiator%太阳能电池作为天线辐射体的RFID标签天线的设计

    Institute of Scientific and Technical Information of China (English)

    马建欢; 李建雄; 肖康; 张世林; 毛陆虹

    2013-01-01

    利用HFSS v12软件设计了一种太阳能电池作为天线辐射体的RFID电子标签天线.利用太阳能电池的射频特性,将太阳能电池作为天线的辐射贴片.因此太阳能电池既可以提供能源,也可以发送和接收电磁波;提出的天线为多层结构,采用H形缝隙耦合馈电方式,可以较容易实现宽频谐振以及天线与芯片的阻抗匹配;给出了该天线的仿真结果,仿真结果表明天线性能良好,满足RFID应用要求.%The RFID tag antenna with integrated solar cells as antenna radiator is designed by software HFSS vl2. Using the RFID properties of the solar cells, the radiating patch element of a planar antenna is replaced by a solar cell. The original feature of a solar cell remains, but additionally the cell is now able to receive and transmit electromagnetic waves. The structure with multiple layers and H-shaped aperture coupled is used to achieve broadband as well as the match between the antenna and chip. Simulations are given to verify present design, and the results show that the designed antenna with good performance is satisfied for RFID application.

  20. 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

  1. Broadband Corrugated Square-Shaped Monopole Antenna

    OpenAIRE

    S. D. Ahirwar; C. Sairam

    2011-01-01

    Design and development of a corrugated square-shaped monopole antenna is presented with measured results. The operational bandwidth of the antenna is 300 MHz–3000 MHz. The antenna is derived from a square-shaped planar monopole antenna. This basic square-shaped radiating element is corrugated in its lateral dimension. This corrugation reduces the lateral dimension of the antenna by 60%. Electrical performance of this antenna is better than its parent counterpart. This paper presents design an...

  2. Miniature microwave plasma antenna at 2.45 GHz

    Science.gov (United States)

    Vachkov, Vasil; Kiss'ovski, Zhivko

    2015-12-01

    New unique miniature plasma antenna driven by a one microwave signal at frequency of 2.45 GHz is constructed and tested. The length of the antenna (l = 16 mm) is much shorter than the free space wavelength of the signal. The parameters of the plasma column (n = 2.6±0.4×1018 m-3, Te = 3.1±0.2 eV) are obtained from argon emission spectrum by applying the line ratio method. The simulations of this monopole antenna reveal that in the standing wave regime the plasma antenna is effective transmitter at a frequency of 2.45 GHz. The results we obtained show that the shape of the radiation pattern of the plasma antenna depends on the plasma density, the exciter and the distance above the grounded plane.

  3. Direction Finding Using Multiple Sum and Difference Patterns in 4D Antenna Arrays

    Directory of Open Access Journals (Sweden)

    Quanjiang Zhu

    2014-01-01

    Full Text Available Traditional monopulse systems used for direction finding usually face the contradiction between high angle precision and wide angle-searching field, and a compromise has to be made. In this paper, the time modulation technique in four-dimensional (4D antenna array is introduced into the conventional phase-comparison monopulse to form a novel direction-finding system, in which both high angle resolution and wide field-of-view are realized. The full 4D array is divided into two subarrays and the differential evolution (DE algorithm is used to optimize the time sequence of each subarray to generate multibeams at the center frequency and low sidebands. Then the multibeams of the two subarrays are phase-compared with each other and multiple pairs of sum-difference beams are formed at different sidebands and point to different spatial angles. The proposed direction-finding system covers a large field-of-view of up to ±60° and simultaneously maintains the advantages of monopulse systems, such as high angle precision and low computation complexity. Theoretical analysis and experimental results validate the effectiveness of the proposed system.

  4. Deployable Wide-Aperture Array Antennas

    Science.gov (United States)

    Fink, Patrick W.; Dobbins, Justin A.; Lin, Greg Y.; Chu, Andrew; Scully, Robert C.

    2005-01-01

    Inexpensive, lightweight array antennas on flexible substrates are under development to satisfy a need for large-aperture antennas that can be stored compactly during transport and deployed to full size in the field. Conceived for use aboard spacecraft, antennas of this type also have potential terrestrial uses . most likely, as means to extend the ranges of cellular telephones in rural settings. Several simple deployment mechanisms are envisioned. One example is shown in the figure, where the deployment mechanism, a springlike material contained in a sleeve around the perimeter of a flexible membrane, is based on a common automobile window shade. The array can be formed of antenna elements that are printed on small sections of semi-flexible laminates, or preferably, elements that are constructed of conducting fabric. Likewise, a distribution network connecting the elements can be created from conventional technologies such as lightweight, flexible coaxial cable and a surface mount power divider, or preferably, from elements formed from conductive fabrics. Conventional technologies may be stitched onto a supporting flexible membrane or contained within pockets that are stitched onto a flexible membrane. Components created from conductive fabrics may be attached by stitching conductive strips to a nonconductive membrane, embroidering conductive threads into a nonconductive membrane, or weaving predetermined patterns directly into the membrane. The deployable antenna may comprise multiple types of antenna elements. For example, thin profile antenna elements above a ground plane, both attached to the supporting flexible membrane, can be used to create a unidirectional boresight radiation pattern. Or, antenna elements without a ground plane, such as bow-tie dipoles, can be attached to the membrane to create a bidirectional array such as that shown in the figure. For either type of antenna element, the dual configuration, i.e., elements formed of slots in a conductive

  5. Design of a Miniaturized Meandered Line Antenna for UHF RFID Tags

    Science.gov (United States)

    Islam, Mohammad Tariqul; Rowe, Wayne S. T.; Kibria, Salehin; Jit Singh, Mandeep; Misran, Norbahiah

    2016-01-01

    A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919–923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for ‘place and tag’ application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP). PMID:27533470

  6. Design of a Miniaturized Meandered Line Antenna for UHF RFID Tags.

    Science.gov (United States)

    Rokunuzzaman, Md; Islam, Mohammad Tariqul; Rowe, Wayne S T; Kibria, Salehin; Jit Singh, Mandeep; Misran, Norbahiah

    2016-01-01

    A semi-circle looped vertically omnidirectional radiation (VOR) patterned tag antenna for UHF (919-923 MHz for Malaysia) frequency is designed to overcome the impedance mismatch issue in this paper. Two impedance matching feeding strips are used in the antenna structure to tune the input impedance of the antenna. Two dipole shaped meandered lines are used to achieve a VOR pattern. The proposed antenna is designed for 23-j224 Ω chip impedance. The antenna is suitable for 'place and tag' application. A small size of 77.68×35.5 mm2 is achieved for a read range performance of 8.3 meters using Malaysia regulated maximum power transfer of 2.0 W effective radiated power (ERP). PMID:27533470

  7. Modified Sierpinski Gasket Patch Antenna for UMTS and 2.4/5.2 WLAN

    Directory of Open Access Journals (Sweden)

    Y. E. Ali

    2013-05-01

    Full Text Available A modified Sierpinski Gasket fractal antenna for multiband application is proposed in this paper. The modified ground plane and the microstrip feed are used to obtain the wider bandwidth at the resonance frequency. The antenna is designed and printed on two layers FR-4 substrate (ϵr=4.4 and h=1.6 mm to cover the UMTS and 2.4/5.2 WLAN. The radiation pattern of the proposed antenna is similar to an omnidirectional. The proposed antenna has maximum gain of 1.88, 1.6, 4.31 dB at 2, 2.4, 5.2 GHz, respectively The properties of the antenna such as return losses, radiation pattern, input resistance and gain are determined via numerical CST Microwave Studio 2010 software.

  8. Triple Band Hexagonal Meander-line Monopole Antenna for Wireless Applications

    Directory of Open Access Journals (Sweden)

    Manali Dongre

    2013-08-01

    Full Text Available In this paper, planar monopole antenna for wireless applications with triple band has been proposed. It simply consists of hexagonal meander-line structure and defected ground plane, which occupy a small PCB area of 50×60×1.676 mm3. The proposed antenna has a measured impedance bandwidths of 1.689-1.781GHz, 2.49-2.71GHz and 2.75-2.98GHz which cover GSM1800 and 2.5WIMAX bands. The antenna has three distinct frequency bands centered at 1.74GHz, 2.63GHz and 2.93GHz. The radiation pattern and resonant frequency are mainly affected by meandered strip and a rectangular defected ground plane. The impedance bandwidth, current distribution, radiation patterns, gain and efficiency of the antenna are studied by computer simulation and measurement. The proposed antenna is fed by a coaxial probe through SMA connector.

  9. Posthumous Numerical Study of DTV Broadcast Antenna Integration with Prototype Stratospheric Airship Gondola

    Directory of Open Access Journals (Sweden)

    Gray Derek

    2008-01-01

    Full Text Available Abstract As a follow-on to the 2002 digital television (DTV broadcast demonstration from a solar-powered stratospheric flying wing, a prototype stratospheric airship was used for a more realistic DTV broadcast demonstration in 2004, albeit at a lower altitude. The DTV signal was occasionally lost at the receiver directly below the airship during the demonstration. Adverse antenna-vehicle integration effects were investigated using a commercially available antenna simulation software, because the radiation pattern of the antenna on the airship could not be measured directly. The ground handling bars on the airship gondola were found to introduce deep and sharp nulls into the radiation pattern of the broadcast antenna. Some mitigation techniques that would have fitted within the constraints of the time are discussed. Changing to nonconductive ground handling bars and a multiturn helical antenna would have avoided the problem, according to the simulation results.

  10. Posthumous Numerical Study of DTV Broadcast Antenna Integration with Prototype Stratospheric Airship Gondola

    Directory of Open Access Journals (Sweden)

    Ryu Miura

    2008-09-01

    Full Text Available As a follow-on to the 2002 digital television (DTV broadcast demonstration from a solar-powered stratospheric flying wing, a prototype stratospheric airship was used for a more realistic DTV broadcast demonstration in 2004, albeit at a lower altitude. The DTV signal was occasionally lost at the receiver directly below the airship during the demonstration. Adverse antenna-vehicle integration effects were investigated using a commercially available antenna simulation software, because the radiation pattern of the antenna on the airship could not be measured directly. The ground handling bars on the airship gondola were found to introduce deep and sharp nulls into the radiation pattern of the broadcast antenna. Some mitigation techniques that would have fitted within the constraints of the time are discussed. Changing to nonconductive ground handling bars and a multiturn helical antenna would have avoided the problem, according to the simulation results.

  11. Topology Optimization of Sub-Wavelength Antennas

    DEFF Research Database (Denmark)

    Erentok, Aycan; Sigmund, Ole

    2011-01-01

    We propose a topology optimization strategy for the systematic design of a three-dimensional (3D), conductor-based sub-wavelength antenna. The post-processed finite-element (FE) models of the optimized structure are shown to be self-resonant, efficient and exhibit distorted omnidirectional......, elliptically polarized far-field radiation patterns. The computed approximate Q value for this antenna is QZ(ω0)≈ 7.74 for ω0=2π × 350.8 MHz and it is 1.64 times larger than the theoretical lower bound value....

  12. ANTENNAS ARRAY ADJUST WITH ADAPTIVE NEURONAL SYSTEM

    Directory of Open Access Journals (Sweden)

    A. Padrón

    2004-12-01

    Full Text Available In this work an array failure correction for Linear Antenna Array (LAA is presented. This is carried out by means ofan Adaptive Artificial Neural Network (AANN that adjusts the amplitude and phase at beamforming. Theappropriated corrections are given, when one, or two, or three elements have a failure in the antenna linear array.The AANN corrects the corresponding parameters in the radiation pattern obtained due to the failure, when weknow the coefficients of the array factor (AF. This yields a reduction of side lobe level and some interferencesdisappear.

  13. Demonstration of a directional sonic prism in two dimensions using an air-acoustic leaky wave antenna

    International Nuclear Information System (INIS)

    Analysis and experimental demonstration of a two-dimensional acoustic leaky wave antenna is presented for use in air. The antenna is comprised of a two-dimensional waveguide patterned with radiating acoustic shunts. When excited using a single acoustic source within the waveguide, the antenna acts as a sonic prism that exhibits frequency steering. This design allows for control of acoustic steering angle using only a single source transducer and a patterned aperture. Aperture design was determined using transmission line analysis and finite element methods. The designed antenna was fabricated and the steering angle measured. The performance of the measured aperture was within 9% of predicted angle magnitudes over all examined frequencies

  14. Demonstration of a directional sonic prism in two dimensions using an air-acoustic leaky wave antenna

    Energy Technology Data Exchange (ETDEWEB)

    Naify, Christina J., E-mail: christina.naify@nrl.navy.mil; Rohde, Charles A.; Calvo, David C.; Orris, Gregory J. [U.S. Naval Research Laboratory, Code 7165, Washington, DC 20375 (United States); Guild, Matthew D. [National Research Associateship Program, U.S. Naval Research Laboratory, Washington, DC 20375 (United States)

    2015-09-28

    Analysis and experimental demonstration of a two-dimensional acoustic leaky wave antenna is presented for use in air. The antenna is comprised of a two-dimensional waveguide patterned with radiating acoustic shunts. When excited using a single acoustic source within the waveguide, the antenna acts as a sonic prism that exhibits frequency steering. This design allows for control of acoustic steering angle using only a single source transducer and a patterned aperture. Aperture design was determined using transmission line analysis and finite element methods. The designed antenna was fabricated and the steering angle measured. The performance of the measured aperture was within 9% of predicted angle magnitudes over all examined frequencies.

  15. 带寄生贴片的圆盘形方向图可重构天线设计%Design of a circular disc-shaped pattern reconfigurable antenna with parasitic patch

    Institute of Scientific and Technical Information of China (English)

    王安国; 蔡晓涛; 冷文

    2011-01-01

    提出了一种新的带寄生贴片的圆盘形方向图可重构天线。天线主要由位于中心的圆形贴片和周围环绕的五个带U型槽的扇环形寄生贴片组成。该天线工作在5.5GHz WiMAX(全球微波接入互操作性)波段范围内,在谐振频率点具有较好的阻抗匹配特性。通过控制开关,天线可以在θ=45°的面内实现五种定向方向图变化。计入方向图增益及波瓣宽度,可以实现波束全向覆盖。天线方向图的旁瓣和后瓣较小,主瓣方向最大增益可达6.3dB,定向辐射特性显著,具有较强的抗干扰能力。该天线尺寸小、剖面低。还分析了一些重要结构参量对天线性能的影响。天线的仿真与测试结果具有较好的一致性。%A novel circular disc-shaped pattern reconfigurable antenna with parasitic patches is proposed in this paper.The antenna mainly consists of the central circular patch and five surrounding fan ring parasitic patches with U-shaped slot.The proposed antenna can work in the 5.5GHzWiMAX(World Interoperability for Microwave Access)frequency band and has a good performance of impedance matching at the resonant frequency.By controlling the states of five switches,the main lobe of each pattern directs to one of five different directions in the plane with the elevation angle of 45 degree.Considering the pattern gain and beam width,the antenna can cover all directions in the elevation plane.The gains of the back lobe and side lobe are both low,and the main lobe is high which gain can reach 6.3dB.A good performance of the antenna in directional radiation characteristic and interference restraining can be achieved.The designed antenna is compact in size and low in profile.The effects on the antenna performance of some important structure parameters are also analyzed in the paper.The simulation and measurement results of the proposed antenna are in a good agreement.

  16. Experimental verification of a broadband planar focusing antenna based on transformation optics

    Science.gov (United States)

    Lei Mei, Zhong; Bai, Jing; Cui, Tie Jun

    2011-06-01

    It is experimentally verified that a two-dimensional planar focusing antenna based on gradient-index metamaterials has a similar performance as that of its parabolic counterpart. The antenna is designed using quasi-conformal transformation optics, and is realized with non-resonant I-shaped metamaterial unit cells. It is shown that the antenna has a broad bandwidth and very low loss. Near-field distributions of the antenna are measured and far-field radiation patterns are calculated from the measured data, which have good agreement with the full-wave simulations. Using all-dielectric metamaterials, the design can be scaled down to find applications at optical frequencies.

  17. Experimental verification of a broadband planar focusing antenna based on transformation optics

    Energy Technology Data Exchange (ETDEWEB)

    Mei Zhonglei; Bai Jing [School of Information Science and Engineering, Lanzhou University, Lanzhou 730000 (China); Cui Tiejun, E-mail: meizl@lzu.edu.cn, E-mail: tjcui@seu.edu.cn [State Key Laboratory of Millimeter Waves, Department of Radio Engineering, Southeast University, Nanjing 210096 (China)

    2011-06-15

    It is experimentally verified that a two-dimensional planar focusing antenna based on gradient-index metamaterials has a similar performance as that of its parabolic counterpart. The antenna is designed using quasi-conformal transformation optics, and is realized with non-resonant I-shaped metamaterial unit cells. It is shown that the antenna has a broad bandwidth and very low loss. Near-field distributions of the antenna are measured and far-field radiation patterns are calculated from the measured data, which have good agreement with the full-wave simulations. Using all-dielectric metamaterials, the design can be scaled down to find applications at optical frequencies.

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

    Directory of Open Access Journals (Sweden)

    Chong Zhang

    2015-01-01

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

  19. DUAL BAND SEMI CIRCULAR DISK PATCH ANTENNA LOADED WITH L-SHAPED SLOT

    Directory of Open Access Journals (Sweden)

    Amel Boufrioua

    2014-11-01

    Full Text Available In this paper, a dual frequency resonance antenna is analysed by introducing L-shaped slot in a semi circular patch, different parametric studies have allows and the results in terms of return loss and radiation pattern are given. It is observed that various antenna parameters are obtained as a function of frequency for different value of slot length and width; it is easy to adjust the upper and the lower band by varying these different antenna parameters. The coaxial feed is used to excite the patch antenna. Theoretical results using Matlab are compared with the simulated results obtained from Ansoft HFSS and shown to be in good agreement.

  20. A NOVEL ULTRA WIDEBAND MONOPOLE ANTENNA WITH BAND-NOTCHED CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    Deng Hongwei; He Xiaoxiang; Yao Binyan; Zhou Yonggang

    2009-01-01

    A simple and compact microstrip-fed Ultra WideBand (UWB) printed monopole antenna with band-notched characteristic is proposed in this paper. The antenna is composed of a square ring with a small strip bar, so that the antenna occupies about 7.69 GHz bandwidth covering 3.11~10.8 GHz with expected band rejection from 5.12 GHz to 5.87 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern is also obtained. This kind of band-notched UWB antenna requires no external filters and thus greatly simplifies the system design of UWB wireless communication.

  1. Design and Measurement of Self-Matched, Dual-Frequency Coplanar-Waveguide-Fed Slot Antennas

    Science.gov (United States)

    Omar, Amjad A.; Scardelletti, Maxmilian C.; Hejazi, Zuhair M.; Dib, Nihad

    2007-01-01

    This report presents two new designs of dual-frequency, coplanar-waveguide-fed, double-folded slot antennas. An important advantage of these antennas is that, because they are self-matched to the feeding coplanar waveguide, they do not need an external matching circuit. This reduces the antenna size and simplifies its design. To verify the designs, the authors measured and compared the return loss and radiation patterns with those obtained using available commercial software with good agreement. Dual-frequency slot antennas;

  2. Characteristics Study of Portable Hand-Held Phone Antenna by MoM

    Institute of Scientific and Technical Information of China (English)

    李玉莹; 徐晓文

    2003-01-01

    The characteristics of one kind of handset antenna are analyzed by the method of moments. By using the Pocklington equation and the Galerkin method, the current distribution on the handset antenna is calculated, the input impedance and radiation patterns are obtained. In addition, the characteristics of monopoles mounted on conducting chassis box with different sizes are analyzed. The results show that the size of the conducting chassis box has significant effect on the performance of the handset antenna. Therefore, appropriately changing the size of the conducting chassis box may improve the performance of the handset antenna.

  3. A novel and simple coplanar waveguide-fed planar monopole antenna for ultra-wideband applications

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, a novel and simple CPW-fed planar monopole antenna is presented for UWB application. The antenna is fabricated on inexpensive FR4 substrate and fed by 50Ω CPW on the same layer. Measured data show that the antenna provides an impedance bandwidth of about 8GHz for the return loss less than 10dB. It is also observed that the radiation patterns are nearly omni-directional over the entire frequency range. Details of the proposed antenna are presented, and simulated results are presented and discussed.

  4. SANTANA- Smart Antenna Terminal Design

    OpenAIRE

    Liu, Ying

    2006-01-01

    This project is embedded in SANTANA (Smart Antenna Terminal) project. The project goal is to design a Ka-band circularly polarized antenna radiator for the receiver SANTANA system. The research work focuses on two types of circularly polarized antennas: aperture-coupled patch antenna and CPW-fed patch antenna. A two steps design process is used. Firstly, only the antennas and their feed structure are designed and optimized. Secondly, a via-transition to connect to a MMIC layer is added. When ...

  5. Patterns of Failure for Pediatric Glioblastoma Multiforme Following Radiation Therapy.

    Science.gov (United States)

    Shabason, Jacob E; Sutton, David; Kenton, Owen; Guttmann, David M; Lustig, Robert A; Hill-Kayser, Christine

    2016-08-01

    Despite aggressive multimodal therapy for pediatric glioblastoma multiforme (GBM), patient survival remains poor. This retrospective review of patients with GBM aims to evaluate the patterns of failure after radiation therapy (RT). The study included 14 pediatric patients treated with RT at the Children's Hospital of Philadelphia from 2007 to 2015. With a median follow-up of 16.9 months, 13 (92.9%) developed recurrent disease. Of recurrences, nine (69.2%) were in-field, three (23.1%) were marginal, and one (7.7%) was distant. The majority of patients treated with adjuvant radiation failed in the region of high-dose RT, indicating the need for improvements in local therapy. PMID:27128519

  6. 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.

  7. A True Metasurface Antenna

    Science.gov (United States)

    Badawe, Mohamed El; Almoneef, Thamer S.; Ramahi, Omar M.

    2016-01-01

    We present a true metasurface antenna based on electrically-small resonators. The resonators are placed on a flat surface and connected to one feed point using corporate feed. Unlike conventional array antennas where the distance between adjacent antennas is half wavelength to reduce mutual coupling between adjacent antennas, here the distance between the radiating elements is electrically very small to affect good impedance matching of each resonator to its feed. A metasurface antenna measuring 1.2λ × 1.2λ and designed to operate at 3 GHz achieved a gain of 12 dBi. A prototype was fabricated and tested showing good agreement between numerical simulations and experimental results. Through numerical simulation, we show that the metasurface antenna has the ability to provide beam steering by phasing all the resonators appropriately.

  8. Radiation Pattern Reconstruction from the Near-Field Amplitude Measurement on Two Planes Using PSO

    Directory of Open Access Journals (Sweden)

    Z. Novacek

    2005-12-01

    Full Text Available The paper presents a new approach to the radiation patternreconstruction from near-field amplitude only measurement over a twoplanar scanning surfaces. This new method for antenna patternreconstruction is based on the global optimization PSO (Particle SwarmOptimization. The paper presents appropriate phaseless measurementrequirements and phase retrieval algorithm together with a briefdescription of the particle swarm optimization method. In order toexamine the methodologies developed in this paper, phaselessmeasurement results for two different antennas are presented andcompared to results obtained by a complex measurement (amplitude andphase.

  9. Backfire antennas with dipole elements

    DEFF Research Database (Denmark)

    Nielsen, Erik Dragø; Pontoppidan, Knud

    1970-01-01

    A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating...... the surface current distribution on the reflector plate. Numerical results obtained for Yagi backfire antennas and short-backfire antennas using this theory are compared with experimental results....

  10. Hollowness of the observed auroral kilometric radiation pattern

    International Nuclear Information System (INIS)

    Presumably also generated by electron cyclotron emission, the earth's auroral kilometric radiation would be expected to exhibit a hollow pattern in the direction of the source magnetic field, similar to that reported for the comparable emissions from Jupiter. Although previously overlooked, such hollowness is clearly present in the new pattern measurements of Green and Gallagher (1985) at 56 kHz, occupying source-centered latitudes of 30 degree to 45 degree and hence occurring exactly where it was predicted and previously observed. Being distributed in longitude and spanning the entire evening sector, presumably reflecting a similar longitudinal distribution of auroral zone sources, this hollowness is attributed to sources beamed preferentially in the poleward magnetic meridian

  11. Designing of Circular and Square Type Fractal Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    Dr. Yogesh Bhomia

    2014-09-01

    Full Text Available This paper presents a design of microstrip patch antenna combining circular and square slots by cutting different slots on rectangular microstrip antenna and experimentally studied on IE3D software. This design is achieved by cutting multi shapes in square pattern combining with circular and square slots & placing a microstrip line feed. This design has been studied in III iterations. The radiation pattern of the proposed microstrip antennas maintained because of the self similarity and centro-symmetry of the fractal shapes. With fractal shapes patch antenna is designed on a FR4 substrate of relative permittivity of 4.4 and thickness 1.524mm and mounted above the ground plane at a height of 6 mm. Details of the measured and simulated results of the case-by-case iterations are presented & discussed

  12. Null-steering techniques for application to large array antennas

    Science.gov (United States)

    Hockham, G. A.; Cho, C.; Parr, J. C.; Wolfson, R. I.

    A multimode waveguide can be employed to design an antenna which produces a beam for each propagating mode. A dual-beam waveguide slot array is particularly attractive. The antenna is compact, highly efficient, and has lower sidelobe-level performance than can be achieved with conventional monopulse techniques. Adaptive phase steering for jammer nulling is considered, taking into account a large phased array using a series feed system. The considered configuration was selected for computer simulation. A description is presented of a multiple beam antenna with independent steerable nulls. The multiple beam low-sidelobe antenna configuration has the ability to provide a radiation pattern with multiple and independently-located nulls, with minimal effect on the sidelobes of the unperturbed pattern.

  13. Experiments with Dipole Antennas

    Science.gov (United States)

    Kraftmakher, Yaakov

    2009-01-01

    Employment of a data-acquisition system for data collection and calculations makes experiments with antennas more convenient and less time consuming. The determined directional patterns of the dipole antennas of different lengths are in reasonable agreement with theory. The enhancement of the signal by using a reflector is demonstrated, and a…

  14. Design of Dual-Band Electrically Small Micro-strip Antenna with wave type Slot as Complementary of folded-dipole antenna for C & X Bands

    Directory of Open Access Journals (Sweden)

    Prof. Jagan Mohan Rao S

    2014-03-01

    Full Text Available This paper presents a new electrically small rectangular probe-fed micro-strip patch antenna loaded with material Rogers rt/duriod5880(tm. The present dissertation deals with Electrically small antenna which are electrically small compared to wave length.the performance of electrically small antenna are closely related to their electrical size, so the gain can be increased to maintain radiating efficiency. The micro-strip patch antennas have been widely used in satellite and telecommunications for their good characteristics such as light weight, in expensive, low cost and so on. Here in this design slots are placed to form folded dipole, which increases the band width of the antenna. Different parameters like returnloss,gain (2d&3d, radiation pattern in θ, Ø directions, current distribution, E&H fields and vswr are simulated in HFSS 13.0.This type of proposed patch can be used for various applications in C & X-Bands.

  15. Reconfigured and Notched Tapered Slot UWB Antenna for Cognitive Radio Applications

    Directory of Open Access Journals (Sweden)

    Tamer Aboufoul

    2012-01-01

    Full Text Available A compact reconfigurable and notched ultra-wideband (UWB tapered slot antenna (TSA is presented. The antenna reconfiguration operation principle relies on 2 mechanisms: in the first mechanism a resonator parasitic microstrip line electrically coupled to the TSA is used to notch the TSA at a specific frequency and the second mechanism relies on changing the input impedance matching of the antenna by means of changing the length of a stub line extended from an additional tiny partial ground on the back side of the antenna. The reflection coefficient, radiation patterns, and gain simulations and measurements for the proposed antenna are presented to verify the design concepts featuring a very satisfactory performance. Total efficiency simulations and measurements are also presented to highlight the filtering performance of the reconfigured antenna. When the antenna was reconfigured from the UWB to work into multiple frequency bands, the radiation patterns were still the same and the total peak gain has slightly improved compared to the UWB case. In addition, when the antenna operated in the notched mode, the gain has significantly dropped at the notch frequency. The simplicity and flexibility of the proposed multimode antenna make it a good candidate for future cognitive radio front ends.

  16. Radiation patterns of multi-moded corrugated horns for far-IR space applications

    Science.gov (United States)

    Murphy, J. Anthony; Colgan, Ruth; O'Sullivan, Creidhe; Maffei, Bruno; Ade, Peter

    2001-12-01

    Multi-moded horn antennas are now being proposed for far-IR space imaging systems in which diffraction limited resolution is not required (e.g. the High-Frequency Instrument (HFI) on the ESA PLANCK Surveyor). In such systems individual modes in the waveguide filter section feeding the horn can couple independently to an overmoded detector (such as a bolometer in an integrating cavity). The number of modes is chosen to optimize the coupling efficiency to the source without compromising any spillover losses. We consider in detail the case of a cylindrically symmetric corrugated configuration, presenting two alternative techniques for modelling such few-moded systems. The first approach is based on a mode-matching description of propagation in a non-uniform waveguide structure, while the second approach makes use of hybrid mode solutions for a waveguide with corrugated walls assuming a uniform but non-isotropic impedance. We present practical examples comparing the radiation patterns predicted by both models.

  17. 赋形波束共形天线口径综合与方向图分析%Analysis on Shaped-beam Aperture Synthesis and Radiation Patternof Conformal Antenna

    Institute of Scientific and Technical Information of China (English)

    张继浩; 王化宇; 李丽娴; 黄一; 章泉源

    2016-01-01

    In order to meet the special requirement of conformal antenna array,a novel shaped⁃beam aperture synthetic method of conformal antenna is proposed,the corresponding calculation and optimization results are provided.The Woodward and Chebyshev linear array synthetic methods are employed to obtain the planar array distribution,which is projected to the cylinder conformal array to achieve the required aperture distribution.The phase and amplitude errors are induced in the antenna elements,and the fabrication and experi⁃ment techniques are considered for error correction,which is valuable for antenna engineering design.The simulated radiation pattern indicates that the proposed method can be applied in shaped⁃beam and low sidelobe conformal aperture array.%针对工程领域对共形阵列天线波束的要求日渐特殊,给出了一种赋形波束共形天线口径的综合方法,以及相应的数值计算和优化结果。在直线阵的基础上结合Woodward综合理论和切比雪夫综合理论,并把综合结果通过投影口径综合法运用到柱面共形阵。将幅度与相位的误差引入各个天线单元通道中,同时考虑到现有加工试验手段对误差的修正,突出了本方法对天线工程设计的指导意义。仿真结果表明,用该方法可以综合常用波束形状和较低副瓣的共形天线口径。

  18. A New Fractal-Based Miniaturized Dual Band Patch Antenna for RF Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Sika Shrestha

    2014-01-01

    Full Text Available The growth of wireless communications in recent years has made it necessary to develop compact, lightweight multiband antennas. Compact antennas can achieve the same performance as large antennas do with low price and with greater system integration. Dual-frequency microstrip antennas for transmission and reception represent promising approach for doubling the system capacity. In this work, a miniaturized dual band antenna operable at 2.45 and 5.8 GHz is constructed by modifying the standard microstrip patch antenna geometry into a fractal structure. In addition to miniaturization and dual band nature, the proposed antenna also removes unwanted harmonics without the use of additional filter component. Using a finite-element-method-based high frequency structure simulator (HFSS, the antenna is designed and its performance in terms of return loss, impedance matching, radiation pattern, and voltage standing wave ratio (VSWR is demonstrated. Simulation results are shown to be in close agreement with performance measurements from an actual antenna fabricated on an FR4 substrate. The proposed antenna can be integrated with a rectifier circuit to develop a compact rectenna that can harvest RF energy in both of these frequency bands at a reduction in size of 25.98% relative to a conventional rectangular patch antenna.

  19. 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.

  20. Investigation of spherical and cylindrical Luneburg lens antennas by the Green's function method

    Science.gov (United States)

    Knyazev, S.; Korotkov, A.; Panchenko, B.; Shabunin, S.

    2016-03-01

    Luneburg lens antenna radiation fields are calculated with Green's functions of spherical and cylindrical layered structures. Electric field components of spherical and cylindrical Luneburg lenses excited by linear and circular polarized incident field are analysed. Dipole, slot and aperture antennas are described by electric and magnetic extraneous currents. Radiation patterns of cylindrical and spherical Luneburg lens are analysed. Co-polarized and cross-polarized field radiation patterns are shown. The proposed method significantly reduces the computing time for multi-layered lenses in comparison with the most commonly used in antenna design. The first step antenna structure optimization may be performed for a shorter time. The results may be used as the first approximation for Ansys HFSS and other software.

  1. Investigation of microwave antennas with improved performances

    Science.gov (United States)

    Zhou, Rongguo

    This dissertation presents the investigation of antennas with improved performances at microwave frequencies. It covers the following three topics: the study of the metamaterial with near-zero index of refraction and its application in directive antenna design, the design technique of a wideband circularly polarized patch antenna for 60GHz wireless application and the investigation of a novel direction of arrival (DOA) estimation technique inspired by human auditory system. First, the metamaterial composed of two-dimensional (2-D) metallic wire arrays is investigated as an effective medium with an effective index of refraction less than unity (neff effective medium parameters (permittivity epsilon eff, permeability mueff and neff ) of a wire array are extracted from the finite-element simulated scattering parameters and verified through a 2-D electromagnetic band gap (EBG) structure case study. A simple design methodology for directive monopole antennas is introduced by embedding a monopole within a metallic wire array with neff effect of the monopole antenna is demonstrated in both simulation and experiment at X-band (8 -- 12 GHz). The measured antenna properties including return loss and radiation patterns are in good agreement with simulation results. Parametric studies of the antenna system are performed. The physical principles and interpretations of the directive monopole antenna embedded in the wire array medium are also discussed. Second, a fully packaged wideband circularly polarized patch antenna is designed for 60GHz wireless communication. The patch antenna incorporates a diagonal slot at the center and features a superstrate and an air cavity backing to achieve desired performances including wide bandwidth, high efficiency and low axial ratio. The detailed design procedure of the circularly polarized antenna, including the design of the microstrip-fed patch antenna and the comparison of the performances of the antenna with different feeding interfaces

  2. Spatially resolving antenna arrays using frequency diversity.

    Science.gov (United States)

    Marks, Daniel L; Gollub, Jonah; Smith, David R

    2016-05-01

    Radio imaging devices and synthetic aperture radar typically use either mechanical scanning or phased arrays to illuminate a target with spatially varying radiation patterns. Mechanical scanning is unsuitable for many high-speed imaging applications, and phased arrays contain many active components and are technologically and cost prohibitive at millimeter and terahertz frequencies. We show that antennas deliberately designed to produce many different radiation patterns as the frequency is varied can reduce the number of active components necessary while still capturing high-quality images. This approach, called frequency-diversity imaging, can capture an entire two-dimensional image using only a single transmit and receive antenna with broadband illumination. We provide simple principles that ascertain whether a design is likely to achieve particular resolution specifications, and illustrate these principles with simulations. PMID:27140887

  3. Design of UWB Planar Monopole Antennas with Etched Spiral Slot on the Patch for Multiple Band-Notched Characteristics

    Directory of Open Access Journals (Sweden)

    Swarup Das

    2015-01-01

    Full Text Available Three types of Ultrawideband (UWB antennas with single, double, and triple notched bands are proposed and investigated for UWB communication applications. The proposed antennas consist of CPW fed monopole with spiral slot etched on the patch. In this paper single, double, and also triple band notches with central frequency of 3.57, 5.12, and 8.21 GHz have been generated by varying the length of a single spiral slot. The proposed antenna is low-profile and of compact size. A stable gain is obtained throughout the operation band except the three notched frequencies. The antennas have omnidirectional and stable radiation patterns across all the relevant bands. Moreover, relatively consistent group delays across the UWB frequencies are noticed for the triple notched band antenna. A prototype of the UWB antenna with triple notched bands is fabricated and the measured results of the antenna are compared with the simulated results.

  4. Triband Compact Antenna for Multistandard Terminals and User's Hand Effect

    Directory of Open Access Journals (Sweden)

    M. Koubeissi

    2009-01-01

    Full Text Available A novel compact wideband triband antenna for mobile terminals based on PIFA element is proposed. The antenna operates at the following frequency bands: Wireless-LAN 802.11 b, g, a and WiMAX 3.5 GHz. The antenna was studied by means of numerical simulations as well as the ground plane dimensions and user's hand effects. The overall size of the radiating element which is 1.8×1.54×9 mm makes it suitable for use in terminals and appropriate to integrated as an internal laptop antenna. The measured bandwidths show that the proposed antenna can cover three bands (2.39–2.48 GHz, (3.36–3.76 GHz, and (4.7–6.3 GHz and the total efficiency is better than 90%. The radiation patterns of the antenna were carried in an anechoic chamber and are given to demonstrate the antenna's performance.

  5. A compact annular ring microstrip antenna for WSN applications.

    Science.gov (United States)

    Wang, Daihua; Song, Linli; Zhou, Hanchang; Zhang, Zhijie

    2012-01-01

    A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN) application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna's performance of a steel installation base. By using a chip resistor of large resistance (120 Ω) the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and -2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

  6. Circularly Polarized Antenna with Wide Projection and Range: A Concept

    Science.gov (United States)

    VanAtta, L. C.; Mailloux, R. J.

    1970-01-01

    The slotted antenna structure discussed in this tech brief radiates a circularly polarized beam pattern over a wide angle. The basic structure, composed of waveguide slots, can be flush mounted in an airplane or spacecraft, and could be used in the communication link between an airplane and an air traffic satellite.

  7. Advanced spherical near-field antenna measurement techniques

    DEFF Research Database (Denmark)

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

    2011-01-01

    The DTU-ESA facility has since the 1980es provided highly accurate antenna radiation pattern measurements and gain calibration by use of the probe corrected spherical nearfield technique, both for ESA (the European Space Agency) and other customers and continues to do so. Recent years activities ...

  8. Microstrip Patch Antenna Bandwidth Enhancement Using AMC/EBG Structures

    Directory of Open Access Journals (Sweden)

    R. C. Hadarig

    2012-01-01

    Full Text Available A microstrip patch antenna with bandwidth enhancement by means of artificial magnetic conductor (AMC/electromagnetic band-gap structure (EGB is presented. The electrical characteristics of the embedded structure are evaluated using MoM simulations. The manufactured prototypes are characterized in terms of return loss, gain, and radiation pattern measurements in an anechoic chamber.

  9. Emission and propagation of Saturn kilometric radiation: Magnetoionic modes, beaming pattern, and polarization state

    Science.gov (United States)

    Lamy, L.; Cecconi, B.; Zarka, P.; Canu, P.; Schippers, P.; Kurth, W. S.; Mutel, R. L.; Gurnett, D. A.; Menietti, D.; Louarn, P.

    2011-04-01

    The Cassini mission crossed the source region of the Saturn kilometric radiation (SKR) on 17 October 2008. On this occasion, the Radio and Plasma Wave Science (RPWS) experiment detected both local and distant radio sources, while plasma parameters were measured in situ by the magnetometer and the Cassini Plasma Spectrometer. A goniopolarimetric inversion was applied to RPWS three-antenna electric measurements to determine the wave vector k and the complete state of polarization of detected waves. We identify broadband extraordinary (X) mode as well as narrowband ordinary (O) mode SKR at low frequencies. Within the source region, SKR is emitted just above the X mode cutoff frequency in a hot plasma, with a typical electron-to-wave energy conversion efficiency of ˜1% (2% peak). The knowledge of the k vector is then used to derive the locus of SKR sources in the kronian magnetosphere, which shows X and O components emanating from the same regions. We also compute the associated beaming angle at the source θ‧ = (k, -B) either from (1) in situ measurements or a model of the magnetic field vector (for local to distant sources) or (2) polarization measurements (for local sources). Obtained results, similar for both modes, suggest quasi-perpendicular emission for local sources, whereas the beaming pattern of distant sources appears as a hollow cone with a frequency-dependent constant aperture angle: θ‧ = 75° ± 15° below 300 kHz, decreasing at higher frequencies to reach θ‧ (1000 kHz) = 50° ± 25°. Finally, we investigate quantitatively the SKR polarization state, observed to be strongly elliptical at the source, and quasi-purely circular for sources located beyond approximately two kronian radii. We show that conditions of weak mode coupling are achieved along the raypath, under which the magnetoionic theory satisfactorily describes the evolution of the observed polarization. These results are analyzed comparatively with the auroral kilometric radiation at

  10. Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

    Directory of Open Access Journals (Sweden)

    L. Zhao

    2013-01-01

    Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

  11. 一种用于电磁脉冲定向辐射的TEM天线设计%TEM antenna design for directional radiation FREMP simulators

    Institute of Scientific and Technical Information of China (English)

    范丽思; 潘晓东; 王赟

    2015-01-01

    In order to solve the problem that the traditional transmission mode electromagnetic pulse (EMP) simulator is relative smaller,a new method to generate EMP radiation field is presented in this paper based on a wire edge curled TEM horn antenna. The influences of the parameters of the antenna and the re⁃sistance absorption to the radiation field are analyzed through numerical simulation. The results show that edge curled TEM horn antenna can enhance the radiation capability significantly in the low frequency band,and can provide theoretical references for the design of directional fast risetime electromagnetic pulse(FREMP)radiating-wave simulators. The feasible of design FREMP radiating-wave simulator is val⁃idated using wire edge curled TEM horn antenna through experiment. The measurement results show that the radiation waveform radiated by the wire edge curled TEM horn antenna successfully meets the require⁃ment of the HEMP in military standards.%针对传统传输式电磁脉冲(EMP)模拟器存在测试空间受限的问题,提出一种基于线栅卷边结构的横电磁波(TEM)天线的定向辐射式快沿电磁脉冲(FREMP)模拟器设计方案。通过数值仿真,研究线栅卷边TEM喇叭天线结构参数和吸收电阻对辐射场的影响,仿真结果表明卷边TEM喇叭天线可以有效提高低频辐射能力,可为研制定向辐射式快沿电磁脉冲模拟器提供理论支撑。另通过实验,验证利用线栅卷边结构TEM喇叭天线研制辐射式快沿电磁脉冲辐射波模拟器的可行性。结果表明:利用线栅卷边结构TEM喇叭天线研制的定向辐射式快沿电磁脉冲模拟器的辐射场可达到高空核电磁脉冲(HEMP)标准的要求。

  12. Bandwidth Enhancement of Probe Fed Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    Parminder Singh

    2013-01-01

    Full Text Available Microstrip patch antenna becomes verypopular day by day because of its ease of analysis andfabrication, low cost, light weight, easy to feed and theirattractive radiation characteristics. Although patchantenna has numerous advantages, it has also somedrawbacks such as restricted bandwidth, and a potentialdecrease in radiation pattern. Different techniques forbandwidth enhancement of conventional rectangularmicrostrip antenna are proposed in this paper. Byincreasing the height of patch , increasing the substratethickness and decreasing the permittivity of substrate the%bandwidth is increased. HFSS Software is used for thesimulation and design calculation of microstrip patchantenna. The return loss, vswr curve, directivity and gainare evaluated.

  13. 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

  14. SAR distributions in interstitial microwave antenna arrays with a single dipole displacement.

    Science.gov (United States)

    Clibbon, K L; McCowen, A; Hand, J W

    1993-09-01

    The use of interstitial microwave antenna array hyperthermia (IMAAH) as a treatment for cancer, in conjunction with radiation therapy and chemotherapy, has been investigated widely. The heating pattern produced by a coherently phased 915 MHz asymmetric antenna array displays the maximum power deposition in the array center. This paper investigates the effect of variable insertion depth between antennas of an array on the heating patterns produced. The "study" of this heating behavior demonstrates a similar effect to that of the variably phased arrays, showing a shift of the heating peak towards the periphery of the tumor, offering a more simple method for the clinical treatment of such tumors. PMID:8288284

  15. Dual polarization flat plate antenna

    Science.gov (United States)

    Kelly, Kenneth C.

    Rectangular waveguides with radiating slots are used in groups to form planar array microwave antennas with large apertures and small depth. Such flat plate antennas are widely used on spacecraft and aircraft. Typically, flat plate antennas provide fixed linear polarization. The present paper describes a new flat plate antenna which produces two coincident beams that are distinguished by their orthogonal linear polarizations. The antenna has two ports, one for each of the coicident beams. Completely external to the antenna, connecting a simple network to those terminal ports enables the antenna to provide right circular polarization from one port and left from the other. A different external network enables the antenna to have arbitrarily adjustable polarizations.

  16. Radiation Characteristics of Chlamydomonas reinhardtii CC125 and Its Truncated Chlorophyll Antenna Transformants tla1, tlaX, and 37RP1-tla1

    OpenAIRE

    Berberoglu, Halil; Pilon, Laurent; Melis, Anastasios

    2008-01-01

    This experimental study reports, for the first time, the radiation characteristics of the unicellular green algae Chlamydomonas reinhardtii strain CC125 and its truncated chlorophyll antenna transformants tla1, tlaX, and tla1-CW+. Photobiological hydrogen production is a sustainable alternative to thermochemical and electrolytic technologies with the possible advantage of carbon dioxide mitigation. However, scale-up of photobioreactors from bench top to industrial scale is made difficult by e...

  17. Measurements of diversity gain and radiation efficiency of the eleven antenna by using different measurement techniques

    DEFF Research Database (Denmark)

    Yang, Jian; Pivnenko, Sergey; Laitinen, Tommi;

    2010-01-01

    This paper presents measurement results of diversity gain and radiation efficiency by using three different measurement techniques: reverberation chamber, spherical near-field anechoic chamber, and multi-probe anechoic chamber. The results are measured over a large 2–8 GHz bandwidth which...

  18. Bandwidth and Gain Enhancement of Patch Antenna with Stacked Parasitic Strips Based on LTCC Technology

    Directory of Open Access Journals (Sweden)

    Li Li

    2014-01-01

    Full Text Available A compact patch antenna with stacked parasitic strips (SPSs based on low temperature cofired ceramic (LTCC technology is presented. By adding three pairs of SPSs above the traditional patch antenna, multiple resonant modes are excited to broaden the bandwidth. At the same time, the SPSs act as directors to guide the antenna radiation toward broadside direction to enhance the gain. The measured results show that the prototype antenna achieves an impedance bandwidth of 16% for S11<-10 dB (32.1–37.9 GHz and a maximum gain of about 8 dBi at 35 GHz. Furthermore, the radiation patterns and gain are relatively stable within the operating bandwidth. The total volume of the antenna is only 8 × 8 × 1.1 mm3.

  19. CPW fed Inverted U-Shape Microstrip Patch Antenna for WLAN/WiMAX Applications

    Directory of Open Access Journals (Sweden)

    Pradeep Kumar

    2014-01-01

    Full Text Available A coplanar waveguide (CPW-fed planar monopole antenna for WiMAX and WLAN applications is presented. The antenna, which occupies a small size, is simply composed of an inverted U-shaped radiating patch with E-shape slot. By carefully selecting the positions of this slot, reasonable bandwidth of the antenna can be obtained so that operating bands covering 2.4/5.2/5.8 GHz WLAN bands and the 2.5/3.5/5.5 GHz WiMAX bands. The measured results also demonstrate that the proposed antenna has appreciable bandwidth and is thus suitable to be integrated within the portable devices for WiMAX/WLAN applications. The various characteristics parameters like S-parameter, VSWR and radiation pattern are studied. The proposed antenna is simulated by using ANSOFT HFSS software

  20. Hybrid Plasmonic Waveguide Fed Broadband Nano-antenna for Nanophotonic Applications

    CERN Document Server

    Saad-Bin-Alam, Md; Rahman, Atiqur; Chowdhury, Arshad M

    2014-01-01

    In this paper, we propose a novel hybrid plasmonic waveguide fed broadband optical patch nano-antenna for nanophotonic applications. Through full wave electromagnetic simulation, we demonstrated our proposed antenna to radiate and receive signal at all optical communication windows (e.g. $\\lambda$ = 850nm, 1310nm & 1550nm) with around 86% bandwidth within the operational domain. Moreover numerical results demonstrate that the proposed nano-antenna has directional radiation pattern with satisfactory gain over all three communication bands. Additionally, we evaluated the antenna performances with two different array arrangements (e.g. one dimensional and square array). The proposed broadband antenna can be used for prominent nanophotonic applications such as optical wireless communication in inter and intra-chip devices, optical sensing and optical energy harvesting etc.

  1. Dual-Band On-Body Repeater Antenna for In-on-On WBAN Applications

    Directory of Open Access Journals (Sweden)

    Jinpil Tak

    2013-01-01

    Full Text Available A dual-band on-body repeater antenna for in-on-on wireless body area network applications is proposed. The proposed antenna has a maximum radiation normal to the human-body surface for communication with implanted devices in the 5.8 GHz industrial, scientific, and medical (ISM band. In addition, to transmit the biological information received from the implanted devices to other on-body devices, the proposed antenna was designed to have a monopole-like radiation pattern along the surface of the human body for communication in the 2.45 GHz ISM band. The antenna was fabricated, and its performance was measured by attaching it to a human-equivalent semisolid phantom. In addition, the human-body effect was studied to ensure antenna performance under an actual situation.

  2. The research of high-directive anisotropic magnetic metamaterial antenna loaded with frequency-selective surface

    Institute of Scientific and Technical Information of China (English)

    Sun Yong-Zhi; Ran Li-Xin; Peng Liang; Wang Wei-Guang; Li Ting; Zhao Xu; Chen Qiu-Lin

    2009-01-01

    This paper uses a Computer Simulation Technology microwave studio to simulate the performance of a new highdirectivity anisotropic magnetic metamaterial antenna loaded with a frequency-selective surface. Frequency-selective surface with cross-dipole element has a great effect on the directivity, radiation pattern, and gain of such an antenna. The experimental results show that frequency-selective surface (FSS) significantly improve the radiation performance of anisotropic magnetic metamaterial antenna. For example, as a single anisotropic magnetic metamaterial antenna, half power beam width is 4 degrees in the H planes, and the gain of this antenna is 19.5dBi at 10GHz, achieving a 2.1 degree increment in half power beam width, and a 7.3dB gain increment by loading with the FSS reflector. The simulating results are consistent with our experimental results.

  3. An isoflux antenna for a low earth orbit satellite mobile communication system

    Science.gov (United States)

    Tsao, C.-H. A.; Jung, P.; Raguenet, G.

    1992-03-01

    In this paper a satellite antenna for a low earth orbit satellite mobile communication system is described. The proposed communication system employs TDD-FD-CDMA (time division duplexing-frequency division-code division multiple access) technique which imposes certain constraints on the antenna design. The antenna discussed in this paper employs six spot beams in conjunction with the CDMA technology to allow the frequency spectrum reuse. The antenna radiation pattern in each beam is shaped to compensate for the path loss differences caused by the slant range differences from the spacecraft to different points on earth. This design provides an isometric radiation flux density on earth within each beam to mitigate the potential near/far problems in a CDMA system. Additional constraints on the antenna design include low profile, light weight and easy deployment to meet the requirements of small satellite implementation of the system.

  4. Modeling of a Plasma Antenna with Inhomogeneous Distribution of Electron Density

    Directory of Open Access Journals (Sweden)

    Zong-sheng Chen

    2015-01-01

    Full Text Available The distribution of the electron density along a plasma antenna can influence the antenna’s performance. But little has been done in this regard in former studies. In this paper, a model of a practical plasma antenna with an inhomogeneous distribution of electron density is founded according to the transmission-line equivalent theory of a metal monopole, from which the current distribution and the radiation pattern of a plasma antenna with appropriate parameters are calculated. The results show that the electrical current distribution, the maximum radiation direction, and the beamwidth of a plasma antenna vary with electron density distributions. To validate the model, the plasma antenna with the same parameters is also simulated based on electromagnetic software HFSS. It is found that the results from the two ways are almost consistent.

  5. Microstrip Phased Array Antennas Printed on Inclined Planes

    Directory of Open Access Journals (Sweden)

    A. Papiernik

    1996-06-01

    Full Text Available This paper presents an analysis of the electromagnetic field radiated by micro-strip patch antennas printed on inclined surfaces. The theoretical approach allows to apply spatial rotations to each source. The computer simulation developed permits us to experiment different antenna structures and two original realisations are proposed: a 2-element array printed on two inclined planes and a 4-element array laid out on a pyramidal surface. In addition, it enables the choice of the phase applied to each radiator to produce a beam deflection function. A good accuracy is obtained between theoretical and experimental results. The aim of this study is to optimise the parameters of such antennas to achieve the desired radiation patterns, from printed phased arrays on conformal surfaces. We also present the theoretical behaviour of a octagonal pyramid.

  6. Development of UAS Design Based on Wideband Antenna Architecture

    Directory of Open Access Journals (Sweden)

    Franklin Drummond

    2015-06-01

    Full Text Available An Unmanned Aerial System (UAS has been developed which is based on an aerodynamically functionalized planar wideband antenna. The antenna utilizes a planar circular dipole metallization scheme. The aerodynamic structure implements a planform similar to the Nutball flier, a hobbyist flight architecture. The resulting codesign achieved a large impedance bandwidth defined by a voltage standing wave ratio (VSWR less than 2 from 100 MHz to over 2 GHz and omnidirectional dipole-like radiation patterns at the lower frequency region and more directional patterns at higher frequencies.

  7. A Directional Interstitial Antenna for Microwave Tissue Ablation: Theoretical and Experimental Investigation.

    Science.gov (United States)

    McWilliams, Brogan T; Schnell, Emily E; Curto, Sergio; Fahrbach, Thomas M; Prakash, Punit

    2015-09-01

    Microwave ablation (MWA) is a minimally invasive thermal therapy modality increasingly employed for the treatment of tumors and benign disease. For successful treatment, complete thermal coverage of the tumor and margin of surrounding healthy tissue must be achieved. Currently available interstitial antennas for MWA have cylindrically symmetric radiation patterns. Thus, when treating targets in proximity to critical structures, caution must be taken to prevent unintended thermal damage. A novel coaxial antenna design for MWA with an asymmetrical cylindrical heating pattern is presented in this paper. This radiation pattern is achieved by employing a hemicylindrical reflector positioned at a critical distance from a conventional coaxial monopole antenna. Finite-element method simulations were employed to optimize the geometric dimensions of the antenna with the objective of minimizing the antenna reflection coefficient at the 2.45-GHz operating frequency, and maximizing volume of the ablation zone. Prototype antennas were fabricated and experimentally evaluated. Simulations indicated an optimal S11 of -32 dB at 2.45 GHz in close agreement with experimental measurements of -29 dB. Ex vivo experiments were performed to validate simulations and observe effects to the antennas' heating pattern with the varying input power and geometry of the reflector. Ablation zones up to 20 mm radially were observed in the forward direction, with minimal heating (less than 4 mm) behind the reflector. PMID:25794385

  8. Characteristics of Double Exponentially Tapered Slot Antenna (DETSA) Conformed in the Longitudinal Direction Around a Cylindrical Structure

    Science.gov (United States)

    Ponchak, George E.; Jordan, Jennifer L.; Chevalier, Christine T.

    2006-01-01

    The characteristics of a double exponentially tapered slot antenna (DETSA) as a function of the radius that the DETSA is conformed to in the longitudinal direction is presented. It is shown through measurements and simulations that the radiation pattern of the conformed antenna rotates in the direction through which the antenna is curved, and that diffraction affects the radiation pattern if the radius of curvature is too small or the frequency too high. The gain of the antenna degrades by only 1 dB if the radius of curvature is large and more than 2 dB for smaller radii. The main effect due to curving the antenna is an increased cross-polarization in the E-plane.

  9. Design of a CPW-feed circularly polarized slot antenna with triangle embedded in half circular disc for UWB applications

    Science.gov (United States)

    Krishna, Ram; Kumar, Raj

    2013-01-01

    A compact (40 mm x 35 mm) coplanar waveguide (CPW) fed slot antenna for circular polarization is presented in this paper. The antenna is designed and fabricated for applications in the ultra-wideband domain of wireless communications where circular polarization is also required. The axial ratio (AR) bandwidth of the proposed antenna is 35.46% (5.8 GHz- 8.3 GHz), while the experimental impedance bandwidth is from 2.8 GHz - 8.6 GHz. The experimental results are very close to the simulated results. The antenna displays a stable radiation pattern and a moderately high gain of around 5 - 6 dB in the useful band.

  10. Probing anisotropies of gravitational-wave backgrounds with a space-based interferometer: geometric properties of antenna patterns and their angular power

    CERN Document Server

    Kudoh, H; Kudoh, Hideaki; Taruya, Atsushi

    2005-01-01

    We discuss the sensitivity to anisotropies of stochastic gravitational-wave backgrounds (GWBs) observed via space-based interferometer. In addition to the un-resolved Galactic binaries as the most promising GWB source of the planned Laser Interferometer Space Antenna (LISA), the extra-galactic sources for GWBs might be detected in the future space missions. The anisotropies of the GWBs thus play a crucial role to discriminate various components of the GWBs. We study general features of antenna pattern sensitivity to the anisotropies of GWBs beyond the low-frequency approximation. We show that the sensitivity of space-based interferometer to GWBs is severely restricted by the data combinations and the symmetries of the detector configuration. The spherical harmonic analysis of the antenna pattern functions reveals that the angular power of the detector response increases with frequency and the detectable multipole moments with effective sensitivity h_{eff}\\sim 10^{-20} Hz^{-1/2} may reach $\\ell \\sim $ 8 - 10 a...

  11. Probing anisotropies of gravitational-wave backgrounds with a space-based interferometer: Geometric properties of antenna patterns and their angular power

    International Nuclear Information System (INIS)

    We discuss the sensitivity to anisotropies of stochastic gravitational-wave backgrounds (GWBs) observed via space-based interferometer. In addition to the unresolved galactic binaries as the most promising GWB source of the planned Laser Interferometer Space Antenna (LISA), the extragalactic sources for GWBs might be detected in the future space missions. The anisotropies of the GWBs thus play a crucial role to discriminate various components of the GWBs. We study general features of antenna pattern sensitivity to the anisotropies of GWBs beyond the low-frequency approximation. We show that the sensitivity of space-based interferometer to GWBs is severely restricted by the data combinations and the symmetries of the detector configuration. The spherical harmonic analysis of the antenna pattern functions reveals that the angular power of the detector response increases with frequency and the detectable multipole moments with effective sensitivity heff∼10-20 Hz-1/2 may reach l∼8-10 at f∼f*=10 mHz in the case of the single LISA detector. However, the cross correlation of optimal interferometric variables is blind to the monopole (l=0) intensity anisotropy, and also to the dipole (l=1) in some case, irrespective of the frequency band. Besides, all the self-correlated signals are shown to be blind to the odd multipole moments (l=odd), independently of the frequency band

  12. The Beaming Pattern of Doppler Boosted Thermal Annihilation Radiation: Application to MeV Blazars

    OpenAIRE

    Skibo, J. G.; Dermer, C. D.; Schlickeiser, R.

    1997-01-01

    The beaming pattern of thermal annihilation radiation is broader than the beaming pattern produced by isotropic nonthermal electrons and positrons in the jets of radio-emitting active galactic nuclei which Compton scatter photons from an external isotropic radiation field. Thus blueshifted thermal annihilation radiation can provide the dominant contribution to the high-energy radiation spectrum at observing angles theta > 1/Gamma, where Gamma is the bulk Lorentz factor of the outflowing plasm...

  13. A new approach to design of quasi-isotropic antenna systems for satellite applications

    DEFF Research Database (Denmark)

    Schjær-Jacobsen, Hans; Hansen, J.E.

    1976-01-01

    The new approach considered takes into account the maximum error of the quasi-isotropic radiation pattern relative to the ideal pattern. A design example involving a spherical satellite with quarter wave monopoles is used to demonstrate the effectiveness of the new approach. An investigation is...... conducted concerning the minimax optimization of power radiation patterns. It is shown that the minimax objective represents a useful alternative to the isotropy concept in the design of quasi-isotropic antenna systems for satellite applications....

  14. Beamformer for Cylindrical Conformal Array of Non-isotropic Antennas

    Directory of Open Access Journals (Sweden)

    ZOU, L.

    2011-02-01

    Full Text Available The principal objective of this investigation is to facilitate minimum variance distortionless response (MVDR beamforming technique for a cylindrical conformal array geometry. An array of directional radiating elements is postulated to cover a surface typical of the cylinder of an aircraft or missile. Borrowing the analysis of conformal array antennas, the authors first derive a deterministic expression that describes the beam pattern of arbitrary weighted cylindrical conformal array. Then, making use of the MVDR beamforming, we derive the beamformer for uniform linear array (ULA of directional antennas which are different from the traditional omnidirectional elements. Thus, the pattern of a directional element is synthesized by the antennas on the same ring array, and we design the MVDR beamformer, which uses MVDR beamforming for ULA of the synthesized pattern. To demonstrate the validity of the method, and cylinder arrays are constructed and experimental results agree well with theoretical expectations.

  15. Focal surfaces of offset dual-reflector antennas

    Science.gov (United States)

    Sletten, C. J.; Shore, R. A.

    1982-01-01

    An analytical technique is described for finding the best focal surfaces for offset-fed dual-reflector antennas. A ray tracing procedure traces the loci of rays incident on the main reflector onto a plane or 'screen' situated perpendicular to a central ray of the antenna system. Given, then, by computer graphics, the best feed locations for azimuth and elevation plane patterns, an aperture diffraction method is used which can compute the sidelobe levels and beamwidths resulting from aperture phase errors on scanned or multibeam patterns. High-magnification Cassegrain or Gregorian antennas, with tilt angles optimised according to Japanese criteria, produce excellent radiation diagrams many beamwidths from the central, unaberrated pattern direction.

  16. Tetraband Small-Size Printed Strip MIMO Antenna for Mobile Handset Application

    Directory of Open Access Journals (Sweden)

    Qinghao Zeng

    2012-01-01

    Full Text Available A compact printed multiple-input multiple-output (MIMO antenna for tetraband (GSM900/1800/1900/UMTS mobile handset application is presented. The proposed MIMO antenna, which consists of two coupled-fed loop antennas with symmetrical configuration, was printed on a 120 * 60 * 0.8 mm3 Fr-4 substrate of relative permittivity of 4.4, loss tangent 0.02. Each element antenna requires only a small area of 22.5 * 25 mm2 on the circuit board. The edge-to-edge spacing between the two elements is only 0.03λ0 of 920 MHz. A slot and a dual-inverted-L-shaped ground branch were added in the ground plane to decrease the mature coupling between the antenna elements. The measured isolation of the proposed antenna is better than 15 dB among the four operating frequency bands. The simulated 3D radiation patterns at 900 MHz and 1900 MHz of both antenna elements show that two loop antennas in general cover complementary space regions with good diversity performance. Detailed antenna impedance matching performance comparisons were done to evaluate the benefit of using different decoupling technology. The envelop correlation coefficient is calculated to represent the diversity performance of the MIMO antenna.

  17. Electrical performance verification methodology for large reflector antennas: based on the P-band SAR payload of the ESA BIOMASS candidate mission

    DEFF Research Database (Denmark)

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

    2013-01-01

    In this paper, an electrical performance verification methodology for large reflector antennas is proposed. The verification methodology was developed for the BIOMASS P-band (435 MHz) synthetic aperture radar (SAR), but can be applied to other large deployable or fixed reflector antennas for which...... antenna. The main emphasis of the work was on the assessment of the achievable pattern and gain uncertainty for the entire antenna and its compliance with the BIOMASS SAR requirements....... the verification of the entire antenna or payload is impossible. The two-step methodology is based on accurate measurement of the feed structure characteristics, such as complex radiation pattern and radiation efficiency, with an appropriate Measurement technique, and then accurate calculation of the radiation...

  18. Ultra-wideband optical leaky-wave slot antennas.

    Science.gov (United States)

    Wang, Yan; Helmy, Amr S; Eleftheriades, George V

    2011-06-20

    We propose and investigate an ultra-wideband leaky-wave antenna that operates at optical frequencies for the purpose of efficient energy coupling between localized nanoscale optical circuits and the far-field. The antenna consists of an optically narrow aluminum slot on a silicon substrate. We analyze its far-field radiation pattern in the spectral region centered around 1550 nm with a 50% bandwidth ranging from 2000 nm to 1200 nm. This plasmonic leaky-wave slot produces a maximum far-field radiation angle at 32° and a 3 dB beamwidth of 24° at its center wavelength. The radiation pattern is preserved within the 50% bandwidth suffering only insignificant changes in both the radiation angle and the beamwidth. This wide-band performance is quite unique when compared to other optical antenna designs. Furthermore, the antenna effective length for radiating 90% and 99.9% of the input power is only 0.5λ(0) and 1.5λ(0) respectively at 1550 nm. The versatility and simplicity of the proposed design along with its small footprint makes it extremely attractive for integration with nano-optical components using existing technologies. PMID:21716477

  19. Generation of OAM Radio Waves Using Circular Vivaldi Antenna Array

    Directory of Open Access Journals (Sweden)

    Changjiang Deng

    2013-01-01

    Full Text Available This paper gives a feasible and simple solution of generating OAM-carrying radio beams. Eight Vivaldi antenna elements connect sequentially and fold into a hollow cylinder. The circular Vivaldi antenna array is fed with unit amplitude but with a successive phase difference from element to element. By changing the phase difference at the steps of 0, ±45°, ±90°, ±135°, and 180°, the OAM radio beam can be generated with mode numbers 0, ±1, ±2, ±3, and 4. Simulations show that the OAM states of ±2 and ±3 are the same as the traditional states, while the OAM states of 0, ±1, and 4 differ at the boresight. This phenomenon can be explained by the radiation pattern difference between Vivaldi antenna and tripole antenna. A solution of distinguishing OAM states is also proposed. The mode number of OAM can be distinguished with only 2 receivers.

  20. A Wideband Single Fed L Slot Circularly Polarized Antenna

    Directory of Open Access Journals (Sweden)

    Nisha

    2014-05-01

    Full Text Available A single-fed circularly polarized (CP patch antenna is designed and built using L-slot loaded patch technique. The antenna is designed on a high dielectric constant (εr = 10.02 substrate which achieves a reasonable bandwidth and axial ratio bandwidth with respect to a U slot antenna. At the operating frequency of 1.575 GHz with the size of the patch is 25mm X 25mm, while ground plane of 60mm X 60mm and the thickness of the substrate is 9.12mm. Bandwidth is enhanced to 18.42% and Axial Ratio Bandwidth by 4% by this design. The other Parameters of antenna like return loss and radiation pattern are also analyzed using HFSS software.

  1. Applications of trimode waveguide feeds in adaptive virtual array antennas

    Science.gov (United States)

    Allahgholi Pour, Z.; Shafai, Lotfollah

    2015-03-01

    This paper presents the formation of an adaptive virtual array antenna in a symmetric parabolic reflector antenna illuminated by trimode circular waveguide feeds with different mode alignments. The modes of interest are the TE11, TE21, and TM01 type modes. The terms TE and TM stand for the transverse electric and transverse magnetic modes, respectively. By appropriately exciting these modes and varying the mode orientations inside the primary feed, the effective source of radiation is displaced on the reflector aperture, while the resulting secondary patterns remain axial. Different antenna parameters such as gain, cross polarization, and phase center locations are investigated. It is demonstrated that the extra third mode facilitates the formation of symmetric virtual array antennas with reasonable cross polarization discriminations at the diagonal plane.

  2. Design considerations for an archimedean slot spiral antenna

    Science.gov (United States)

    Nurnberger, Michael W.; Volakis, John L.

    1995-01-01

    The design goal is to develop a 118-157 MHz, vertically polarized, low-profile (or conformal) antenna as a replacement for VHF AM blade antennas on aircraft. This design is to be arrived at by scaling the dimensions of an antenna designed for a center frequency of 1.1 GHz. The design prior to scaling may have the following maximum dimensions: diameter less than 3.70 in. and thickness less than 0.50 in. Although a four-arm spiral design was originally suggested, a two-arm spiral may also be used, as both mode-1 and mode-2 (sum and difference) radiation patterns aren't required. While a four-arm spiral can easily be designed should both sum and difference patterns be required, the two-arm design will provide the required sum pattern and simplify the design problem somewhat: only one feed is required, and the feed area geometry is more straightforward. Polarization requirements dictate that a slot spiral be used, as opposed to a wire spiral. Two similar radiating structures were considered. The first is the standard archimedean spiral antenna. The second is a hollow archimedean spiral antenna, essentially a standard archimedean spiral with the inner portion removed.

  3. In-the-Ear Circular-Shaped Balanced Inverted-A Antenna for Hearing Instruments

    DEFF Research Database (Denmark)

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

    2016-01-01

    A novel in-the-ear antenna for hearing instruments that operates at 2.45 GHz is presented. The antenna is designed to obtain a polarization perpendicular to the surface of the head in order to optimize the ear-to-ear communication. The antenna consists of a bent dipole with a shorting pin used...... for impedance matching. It is self-resonant and well matched in the entire ISM band from 2.40 GHz to 2.48 GHz. The simulated and measured peak ear-to-ear path gain |S21| is −74.5 dB and −72.9 dB, respectively. The radiation pattern of the antenna is analyzed and the implications of the radiation pattern...

  4. Electrically Small Antenna Covered by Two circular Ring Resonators for C, X, KU band applications

    Directory of Open Access Journals (Sweden)

    I.Govardhani

    2012-04-01

    Full Text Available Electrically small antennas have been an important part of communications engineering since the beginning. The present dissertation deals with electrically small antennas, namely antennas which are no more than(/10 small compared to the wavelength. An important point regarding electrically small antennas is that their performances are closely related to their electrical size. The product of the bandwidth and the gain is a function of the size of the antenna, so that the gain can only be increased at the expense of the bandwidth, and vice versa.In this paper, I will deal with dual-band electrically small antenna (ESA. The miniaturized radiation structure consists of a small ring and concentric split-ring resonator. The resonant response of the proposed radiation structure is characterized by the coupling among two split-ring resonators and the small ring. This interaction provides an additional capacitance to further reduce the total dimension of the resonant electrical length. In this paper my proposed work to verify the improvements in the gain, return loss, radiation patterns, Field pattern, Axial ratio, reflection coefficient (s11 and efficiency of the electrically small antenna.

  5. A Compact Multiband Notch UWB Antenna

    Directory of Open Access Journals (Sweden)

    K. Kumar

    2012-01-01

    Full Text Available A simple and a compact coplanar waveguide (CPW ultrawide band (UWB antenna is presented. Multiband stop function is achieved by two different types of band stop resonators. One is a tilted square spiral slot resonator of different size and length etched on the patch and the other is a coupled resonator etched on the ground plane. These resonators provide considerable increase in notch bandwidth at the stop bands. The proposed antenna has a total size of 18×20.3 mm2. The designed antenna achieves pass band performance at 1.8–2.1 GHz (15.38%, 3.0–3.2 GHz (6.45%, 4.4–4.7 GHz (6.59%, 6.3-6.4 GHz (1.57%, and 8–11.2 GHz (33.33% where VSWR <2 and four stop bands at 2.4–2.8 GHz (15.38%, 3.2–3.7 GHz (14.49%, 5.5–6 GHz (8.69%, and 6.5–7 GHz (7.40% where VSWR is equal to 10. The antenna has a peak gain of 3.8 dBi. The measured results show that the antenna achieves good impedance matching and consistent radiation patterns over an operating bandwidth.

  6. Logarithmic Slots Antennas Using Substrate Integrated Waveguide

    Directory of Open Access Journals (Sweden)

    Jahnavi Kachhia

    2015-01-01

    Full Text Available This paper represents new generation of slotted antennas for satellite application where the loss can be compensated in terms of power or gain of antenna. First option is very crucial because it totally depends on size of satellite so we have proposed the high gain antenna creating number of rectangular, trapezoidal, and I shape slots in logarithm size in Substrate Integrated Waveguide (SIW structure. The structure consists of an array of various shape slots antenna designed to operate in C and X band applications. The basic structures have been designed over a RT duroid substrate with dielectric constant of 2.2 and with a thickness of 0.508 mm. Multiple slots array and shape of slot effects have been studied and analyzed using HFSS (High Frequency Structure Simulator. The designs have been supported with its return loss, gain plot, VSWR, and radiation pattern characteristics to validate multiband operation. All the proposed antennas give gain more than 9 dB and return loss better than −10 dB. However, the proposed structures have been very sensitive to their physical dimensions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

  8. Coupling between minimum scattering antennas

    DEFF Research Database (Denmark)

    Andersen, J.; Lessow, H; Schjær-Jacobsen, Hans

    1974-01-01

    Coupling between minimum scattering antennas (MSA's) is investigated by the coupling theory developed by Wasylkiwskyj and Kahn. Only rotationally symmetric power patterns are considered, and graphs of relative mutual impedance are presented as a function of distance and pattern parameters. Crossed......-dipoles and helices are considered in order to establish a correspondence with simple antenna structures....

  9. Planar Millimeter-Wave Antennas: A Comparative Study

    OpenAIRE

    Pitra, K.; Z. Raida

    2011-01-01

    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.

  10. Multiple band circularly polarized microstrip antenna

    Science.gov (United States)

    Yu, I. P. (Inventor)

    1980-01-01

    A multiple antenna assembly for communicating electromagnetic radiation is disclosed. An antenna element stack is constructed of a plurality of elliptical lamina antenna elements mutally separated by layers of dielectric material, and separated from a ground plane by dielectric material. The antenna assembly is coupled through a feed line in contact with the top antenna element. A conductor joins the remaining antenna elements to the ground plane. Each individual antenna element is operable for communication reception and transmission within a frequency band determined by the size of the particular antenna element. The sizes of the antenna elements may be selected to provide electromagnetic radiation communication over several distinct frequency bands, or to connect the individual bands into a broad band.

  11. Performance Comparison of Symmetric and Offset Reflector Antennas Adaptively Illuminated by Novel Triple Mode Feedhorn

    Directory of Open Access Journals (Sweden)

    Satish K. Sharma

    2012-01-01

    Full Text Available Parabolic symmetric and offset reflector antennas adaptively illuminated using a novel triple-mode feedhorn (TE11+TM01+TE21 with different mode combinations and impedance and radiation performances are presented. The combination of the radiating modes in a feedhorn with proper amplitude and fixed phase values helps in electronically pointing the main beam of the radiating patterns such as that obtained in a beam-steering antenna with limited beam-scan range. This type of radiation performance virtually creates a displaced phase center location for the feedhorn, which, consequently, adaptively illuminates the reflector antenna surface. Impedance-matching bandwidths are preserved for both reflector antennas similar to the case of feedhorn alone. The copolarization gain and peak cross-polarization levels are far better with the offset reflector antenna than the symmetric reflector antenna. Such reflector antennas find applications in ground moving target indicator (GMTI and space based radars. The investigation results are solely computed using FEKO full-wave analysis tool.

  12. Time-Domain Analysis of a Wire Antenna Near Arbitrarily Shaped Conductor Bodies

    Institute of Scientific and Technical Information of China (English)

    Zheng Li-zhi; Xiao Bo-xur; Zhu Guo-qiang; Yang Zi-jie

    2003-01-01

    A time domain electrical field integral equation (TDEFIE) is formulated for the problem of a thin wire antenna in the presence of conductor bodies, and this equation is solved by the method of time marching algorithm. The analysis is valid for any arbitrarily shaped, oriented and positioned wire antennas relative to arbitrarily shaped conductor bodies. Current at the excited point, input admittance and radiation pattern are given and agree with the results computed by the method in frequency domain.

  13. Time-Domain Analysis of a Wire Antenna Near Arbitrarily Shaped Conductor Bodies

    Institute of Scientific and Technical Information of China (English)

    Zheng; Li-Zhi; Xiao; Bo-xun; 等

    2003-01-01

    A time domain electrical field integral equation (TDEFIE) is formulated for the problem of a thin wire antenna in the presence of conductor bodies, and this equation is solved by the method in time marching algorithm. The analysis is valid for any arbitrarily shaped, oriented and positioned wire antennas relative to arbitrarily shaped conductor bodies. Current at the excited point, input admittance and radiation pattern are given and agree with the results computed by the method in frequency domain.

  14. Analysis of RF Front-End Performance of Reconfigurable Antennas with RF Switches in the Far Field

    Directory of Open Access Journals (Sweden)

    Insu Yeom

    2014-01-01

    Full Text Available The RF front-end performances in the far-field condition of reconfigurable antennas employing two commonly used RF switching devices (PIN diodes and RF-MEMS switches were compared. Two types of antennas (monopole and slot representing general direct/coupled feed types were used for the reconfigurable antennas to compare the excited RF power to the RF switches by the reconfigurable antenna types. For the switching operation of the antennas, a biasing circuit was designed and embedded in the same antenna board, which included a battery to emphasize the antenna’s adaptability to mobile devices. The measurement results of each reconfigurable antenna (radiation patterns and return losses are presented in this study. The receiving power of the reference antenna was measured by varying the transmitting power of the reconfigurable antennas in the far-field condition. The receiving power was analyzed using the “Friis transmission equation” and compared for two switching elements. Based on the results of these measurements and comparisons, we discuss what constitutes an appropriate switch device and antenna type for reconfigurable antennas of mobile devices in the far-field condition.

  15. A Compact Annular Ring Microstrip Antenna for WSN Applications

    Directory of Open Access Journals (Sweden)

    Daihua Wang

    2012-06-01

    Full Text Available A compact annular ring microstrip antenna was proposed for a wireless sensor network (WSN application in the 2.4 GHz band. In this paper the major considerations of the conformal antenna design were the compact size and the impact on antenna’s performance of a steel installation base. By using a chip resistor of large resistance (120 Ω the antenna size was reduced to 38% of that a conventional annular ring patch antenna. With the addition of the steel installation base the resonant frequency of the antenna increases about 4.2% and the bandwidth reduces from 17.5% to 11.7% by adjusting the load resistance simultaneously. Several key parameters were discussed and optimized, and the antenna was fabricated and its performance measured. The antenna is well matched at 2.4 GHz with 34.2 dB return loss and –2.5 dBi peak gain. Meanwhile, it exhibits excellent radiation patterns with very low cross-polarization levels.

  16. Miniaturised reconfigurable window slot antenna using mechanical tuning

    Science.gov (United States)

    Beno, A.; Emmanuel, D. S.

    2015-11-01

    A novel design approach of varying the slot width on radiating patch of a microstrip antenna for achieving reconfigurable dual-band operation is proposed. The design of this miniaturised reconfigurable antenna is done without the use of active switches or MEMS. The dual band is obtained by rotating the strips on the patch creating slots and varying the slot width using mechanical tuning. The strip is rotated in angular position from 0° to 90° varying the slot width that alters the resonant frequency of the antenna making it resonate at different frequencies covering the wireless bands for global system for mobile communication, global positioning system, wireless local area network and Bluetooth. This antenna provides a dual-band operation that shifts over the bands depending upon the slot width. This antenna achieves the bandwidth requirement and gain in the bands of operation. The effect of change in slot width on the radiation pattern is also discussed. The prototype antenna is fabricated and tested to prove the proposed concept of design. The measured results are in agreement with the simulated results.

  17. SAR antenna calibration techniques

    Science.gov (United States)

    Carver, K. R.; Newell, A. C.

    1978-01-01

    Calibration of SAR antennas requires a measurement of gain, elevation and azimuth pattern shape, boresight error, cross-polarization levels, and phase vs. angle and frequency. For spaceborne SAR antennas of SEASAT size operating at C-band or higher, some of these measurements can become extremely difficult using conventional far-field antenna test ranges. Near-field scanning techniques offer an alternative approach and for C-band or X-band SARs, give much improved accuracy and precision as compared to that obtainable with a far-field approach.

  18. Microstrip Antennas with Polarization Diversity across a Wide Frequency Range and Phased Array Antennas for Radar and Satellite Communications

    Science.gov (United States)

    Ho, Kevin Ming-Jiang

    The thesis comprises of 3 projects; an L-band microstrip antenna with frequency agility and polarization diversity, X-band phased array antennas incorporating commercially packaged RFIC phased array chips, and studies for Ku/Ka-band shared aperture antenna array. The first project features the use of commercially packaged RF-MEMS SPDT switches, that boasts of high reliability, high linearity, low losses, hermetically packaged and fully compatible for SMTA processes for mass-assembly and production. Using the switches in a novel manner for the feed network, microstrip antennas with polarization diversity are presented. Frequency agility is achieved with the use of tuning diodes to provide capacitive loading to the antenna element. Additional inductance effects from surface-mounted capacitors, and its impact, is introduced. Theoretical cross-polarization of probe-fed antenna elements is presented for both linear and circular polarized microstrip antennas. Designs and measurements are presented, for microstrip antennas with polarization diversity, wide frequency tuning range, and both features. Replacement of the tuning diodes with commercially-packaged high Q RF MEMS tunable capacitors will allow for significant improvements to the radiation efficiency. In another project, multi-channel CMOS RFIC phased-array receiver chips are assembled in QFN packages and directly integrated on the same multi-layered PCB stack-up with the antenna arrays. Problems of isolation from the PCB-QFN interface, and potential performance degradation on antenna array from the use of commercial-grade laminates for assembly requirements, namely potential scan blindness and radiation efficiency, are presented. Causes for apparent drift of dielectric constant for microstrip circuits, and high conductor losses observed in measurements, are introduced. Finally, studies are performed for the design of a Ku/Ka-Band shared aperture array. Different approaches for developing dual-band shared apertures

  19. Parametric Study of Cylindrical Dielectric Resonator Antenna (CDRA Feeder with Symmetric Parabolic Reflector

    Directory of Open Access Journals (Sweden)

    S.M. Ali

    2015-06-01

    Full Text Available In this study a parabolic reflector antenna is designed and fabricated for IEEE 802.11a WLAN application. Initially, a single element circular tuning slot coupled Cylindrical Dielectric Resonator Antenna (CDRA feeder is designed and fabricated for a symmetric parabolic reflector. Subsequently, the designed feeder is integrated at the focal point of the parabolic reflector to provide unidirectional radiation pattern with improved gain and sidelobe levels. The measured fractional impedance bandwidth achieved for the proposed antenna is 1.8% for S11<-10 dB from 5.32 to 5.52 GHz. A radiation pattern with broadside radiation and low back radiation has been obtained. A good measurement gain of approximately 13 dB is achieved over the bandwidth by placing CDRA feeder at the focal point of the parabolic reflector. In addition, a comprehensive parametric study has been conducted to realize the effect of slot size and position on the resonance frequency of the designed feeder. Furthermore, a parametric study of various reflector parameters has also been performed to study the effect of size, depth and focal point of the parabolic reflector on gain of the antenna. Important design factors have been identified from the parametric study of the antenna. The experimental and measured results show that the designed antenna is suitable for IEEE WLAN 802.11a wireless application.

  20. Analysis and design of low profile multiband multifunctional antenna arrays

    Science.gov (United States)

    Hunsicker, Walker F.

    Light-weight phased array antennas for aerospace and mobile applications require utilizing the same antenna aperture to provide multiple functions with dissimilar radiation pattern specifications (e.g., multiband operation for communications and tracking). Multi-functional antennas provide advantages over aggregate antenna clusters by reducing space requirements, and can aid in the optimal placement of all required apertures to provide adequate isolation between channels. Furthermore, the combination of antenna apertures into a common geometry mitigates co-site installation issues by addressing interference within the integrated radiator design itself as opposed to the extensive analysis which is required to configure multiple radiators in close proximity. The combination of multiple radiators into a single aperture can only be achieved with the proper selection of antenna topology and accompanying feed network design. This research proposes a new technique for the design of multiband arrays in which a common aperture is used. Highlighted by this method is the integration of a tri-band array comprised of an X-band (12 GHz) microstrip patch array on a superstrate above printed dual-band (1 and 2 GHz) slot loop antenna arrays in an octave-spaced lattice. The selection of a ground backing reflector is considered for improved gain and system packaging, but restricts the utility of the design principally due to the lambda/4 depth of the ground plane. Therefore, a novel multiband high impedance surfaces (HIS) is proposed to load the slot apertures for reduced height. The novel techniques proposed here will enable the design of a low profile and conformal single aperture supporting multi-band and multi-functional operations.