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Antennas and Propagation, IEEE Transactions on

Issue 2 • Date Feb. 2011

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  • Table of contents

    Page(s): C1 - 349
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  • IEEE Transactions on Antennas and Propagation publication information

    Page(s): C2
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  • The Parametric Optimization of Wire Dipole Antennas

    Page(s): 350 - 356
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (627 KB) |  | HTML iconHTML  

    The shape representation of planar wire dipole antennas of fixed radius is discussed. Away from the feed point the shape can be always represented as a arc-length parametrizable Lipschitz-continuously differentiable curve. The representation is applied to classical directivity optimization design problems as well as impedance optimization problems. By such an optimization, it is shown that directive wire dipoles of length (3/2)λ can be tuned by shape optimization and that the real part of input impedance of λ/2 dipole is bounded from above if the imaginary part must be small. View full abstract»

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  • Inductively-Loaded Yagi-Uda Antenna With Cylindrical Cover for Size Reduction at VHF-UHF Bands

    Page(s): 357 - 362
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    A new technique is employed to reduce the size of Yagi-Uda antennas. The technique consists of adding short circuited cylindrical covers to the structure, making the elements be inductively loaded, and as a result, increase the electric length. A prototype resonating at 660 MHz is developed, and compared to a conventional Yagi-Uda antenna. An effective area reduction of 35% is achieved without decreasing, considerably, the gain, preserving the bandwidth, and front to back lobe ratio. View full abstract»

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  • Compact Coplanar Waveguide (CPW)-Fed Zeroth-Order Resonant Antennas With Extended Bandwidth and High Efficiency on Vialess Single Layer

    Page(s): 363 - 372
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    This paper presents the design and analysis of compact coplanar waveguide (CPW)-fed zeroth-order resonant (ZOR) antennas. They are designed on a CPW single layer where vias are not required. The ZOR phenomenon is employed to reduce the antenna size. The novel composite right/left-handed (CRLH) unit cell on a vialess single layer simplifies the fabrication process. In addition, the CPW geometry provides high design freedom, so that bandwidth-extended ZOR antennas can be designed. The antenna's bandwidth is characterized by the circuit parameters. Based on the proposed bandwidth extension technique, symmetric, asymmetric, and chip-loaded antennas are designed. The ZOR characteristic and bandwidth extension are verified by a commercial EM simulator. Their performances are compared with those of previously reported metamaterial resonant antennas. They provide further size reduction, higher efficiency, easier manufacturing, and extended bandwidth. View full abstract»

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  • Increasing the Bandwidth of Microstrip Patch Antenna by Loading Compact Artificial Magneto-Dielectrics

    Page(s): 373 - 378
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    We realize artificial magneto-dielectric loading for microstrip patch antenna by etching embedded meander-line (EML) array in the ground plane under the patch. The related artificial magneto-dielectric medium belongs to the waveguided metamaterial proposed previously. Both simulation and measurement results show that the proposed patch antenna with the EML array has wider impedance bandwidth than the conventional patch antenna with the same size. Though we have to increase the antenna profile by attaching an additional shield metal plate to suppress the back radiation, the proposed magneto-dielectric loading method requires lower fabrication complexity and lower cost than the existing techniques. View full abstract»

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  • A New Design Method for Single-Feed Circular Polarization Microstrip Antenna With an Arbitrary Impedance Matching Condition

    Page(s): 379 - 389
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    This paper introduces a new analytical method suitable for the design of the single-feed circular polarization (CP) microstrip patch antenna. Specifically, the proposed method imposes simultaneously the circular polarization condition as well as an arbitrary input impedance matching condition. The two conditions are enforced by an analytical method derived from an equivalent circuit model of a quasi-symmetrical patch antenna, and manipulated to control the modal detuning. This method can be used as an aid to speed up the design procedure for CP antennas even working with a numeric CAD tool. The validation of this approach is proven designing and fabricating a prototype implementing an original design, which consists of a circular disc slotted by a concentric elliptical cut with coaxial feed and operating at the center frequency of 2.45 GHz. The fabricated prototype exhibited a return loss of about 19 dB, within an impedance bandwidth of 130 MHz, a measured gain of 3.85 dB and a 0 dB axial ratio at 2.45 GHz with a corresponding modal phase difference of 87 degrees. View full abstract»

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  • Compact Band-Rejected Ultrawideband Slot Antennas Inserting With \lambda /2 and \lambda /4 Resonators

    Page(s): 390 - 397
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    Two compact ultrawideband (UWB) slot antennas with band-rejected characteristics are proposed for UWB communication applications. The entire size of both antennas is as small as 15 mm × 22 mm × 0.8 mm, which is smaller than most of the proposed UWB antennas. The radiator is a stepped slot excited by a 50 Ω feed line. By etching a half-wavelength and a quarter-wavelength slot from the ground plane of UWB slot antennas, respectively, two UWB antennas with band-notched characteristics can be obtained. The potential interference between UWB and WLAN/WiMAX can be reduced. Omnidirectional radiation patterns and constant gain can be observed in the pass bands. Time-domain characteristics of both proposed antennas are analyzed under different conditions. It demonstrates that the time-domain characteristics of the antennas are good enough for UWB applications. The results show that proposed antennas are very suitable for various portable UWB systems. View full abstract»

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  • Millimeter-Wave Microstrip Comb-Line Antenna Using Reflection-Canceling Slit Structure

    Page(s): 398 - 406
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    A microstrip comb-line antenna is developed in the millimeter-wave band. When the element spacing is one guide wavelength for the broadside beam in the traveling-wave excitation, reflections from all the radiating elements are synthesized in phase. Therefore, the return loss increases significantly. Furthermore, re-radiation from elements due to the reflection wave degrades the design accuracy for the required radiation pattern. We propose the way to improve the reflection characteristic of the antenna with arbitrary beam directions including strictly a broadside direction. To suppress the reflection, we propose a reflection-canceling slit structure installed on the feeding line around each radiating element. A 27-element linear array antenna with a broadside beam is developed at 76.5 GHz. To confirm the feasibility of the simple design procedure, the performance is evaluated through the measurement in the millimeter-wave band. View full abstract»

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  • Frequency Steerable Two Dimensional Focusing Using Rectilinear Leaky-Wave Lenses

    Page(s): 407 - 415
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    The concept of frequency steerable two-dimensional electromagnetic focusing by using a tapered leaky-wave line source embedded in a parallel-plate medium is presented. Accurate expressions for analyzing the focusing pattern of a rectilinear leaky-wave lens (LWL) from its constituent leaky-mode tapered propagation constant are described. The influence of the main LWL structural parameters on the synthesis of the focusing pattern is discussed. The ability to generate frequency steerable focusing patterns has been demonstrated by means of an example involving a LWL in hybrid waveguide printed-circuit technology and the results are validated by a commercial full-wave solver. View full abstract»

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  • Sub-Wavelength Profile 2-D Leaky-Wave Antennas With Two Periodic Layers

    Page(s): 416 - 424
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1836 KB) |  | HTML iconHTML  

    A fast and accurate analysis and synthesis technique for high-gain sub-wavelength 2-D Fabry-Perot leaky-wave antennas (LWA) consisting of two periodic metallodielectric arrays over a ground plane is presented. Full-wave method of moments (MoM) together with reciprocity is employed for the estimation of the near fields upon plane wave illumination and the extraction of the radiation patterns of the LWA. This yields a fast and rigorous tool for the characterisation of this type of antennas. A thorough convergence study for different antenna designs is presented and the operation principles of these antennas as well as the radiation characteristics are discussed. Moreover, design guidelines to tailor the antenna profile, the dimensions of the arrays as well as the antenna directivity and bandwidth are provided. A study on the radiation efficiency for antennas with different profiles is also presented and the trade off between directivity and radiation bandwidth is discussed. Numerical examples are given throughout to demonstrate the technique. A finite size antenna model is simulated using commercial software (CST Microstripes 2009) which validates the technique. View full abstract»

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  • Experimental Characterization of a Surfaguide Fed Plasma Antenna

    Page(s): 425 - 433
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    The possibility of using a surfaguide device as plasma source for plasma antenna application has been experimentally investigated. The surfaguide was optimized, realized and used for the ignition of a plasma column to be used as a radiating structure: the coupling with the radiated signal network and plasma antenna efficiency were measured showing that a surfaguide can be effectively used to create and sustain the plasma conductive medium. A plasma diagnostic technique was also developed to evaluate the plasma column length and plasma conductivity with respect to the power supplied. These measurements highlighted that plasma antenna properties are strongly affected by the pump signal and therefore this signal has to be optimized in order to have the highest conductivity. View full abstract»

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  • Experimental Study of the Effect of Modern Automotive Paints on Vehicular Antennas

    Page(s): 434 - 442
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1677 KB) |  | HTML iconHTML  

    Today's automobiles are fitted with antennas for many wireless services, with modern vehicular antennas frequently configured in blade or “shark-fin” housings, or as planar roof mounted antennas. In these configurations vehicle manufacturers may wish to improve the appearance of the finished vehicle by painting these antennas or their coverings. This paper provides experimental results detailing the effect of two commonly used automotive paint chemistries both with and without the metallic particles used to create a “metallic paint” effect. Electrostatic primers are also considered. Narrowband and wideband antennas are investigated, and the effect of these coatings on impedance bandwidth and radiation is observed. View full abstract»

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  • A Toolset Independent Hybrid Method for Calculating Antenna Coupling

    Page(s): 443 - 451
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    Calculation of the electromagnetic interference (EMI) between electrically large antennas mounted on ships is important for a variety of Navy problems. This paper presents a toolset independent hybrid method for calculating the power at receive antenna terminals relative to the power incident on transmit antenna terminals. The hybrid method coupling results are validated against full-wave computational electromagnetic (CEM) simulations and measurements. An advantage of the proposed hybrid approach is that CEM calculations for antenna near-fields and propagation between antennas can be executed with user-preferred tools. In addition, transmit and receive antenna calculations are executed in transmit mode independent of ship structures. Thus, antenna calculations can be stored in a library for calculation reuse and optimization of antenna placement for EMI reduction. View full abstract»

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  • Array Noise Matching—Generalization, Proof and Analogy to Power Matching

    Page(s): 452 - 459
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (438 KB) |  | HTML iconHTML  

    In array antennas with residual coupling, the signal-to-noise ratio (SNR) can suffer from noise coupling from the inputs of the low noise amplifiers (LNAs) to the other channels. As shown recently, the lost SNR can be retrieved by changing the individual matching circuits. This paper explains the theory behind array noise matching and generalizes it for non-equal LNAs and non-reciprocal sources. It also shows an analogy between noise matching of an array and power matching into the complex conjugate of the optimum noise impedances of the individual LNAs. This turns out to be useful for practical noise matching of mutually coupled arrays. In some cases it becomes impossible to reach the theoretical optimum matching with passive matching networks. Therefore an additional boundary condition will be introduced and investigated. View full abstract»

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  • Compact Two-Layer Rotman Lens-Fed Microstrip Antenna Array at 24 GHz

    Page(s): 460 - 466
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1189 KB) |  | HTML iconHTML  

    This paper presents a new design to realize a compact Rotman lens-fed antenna array. The lens-fed antenna has the form of two layers, which is a new approach to reducing the size of the Rotman lens. The approach is demonstrated at 24 GHz aiming for an automotive sensing radar. The lens consists of a top metal layer, a dielectric, a common ground, a dielectric, and a bottom metal layer, in sequential order. The layout of the lens body is placed on the bottom layer and the antennas are placed on the top layer. Both of them are electrically connected through slot transitions. This two-layer structure reduces not only the total size of the lens, but also the loss of the delay lines because the lines can be designed to be as short and straight as possible. The two-layer Rotman lens-fed antenna array is measured in terms of scattering parameters and beam patterns. From the scattering parameters, the power efficiencies of the beam port 1, 2, and 3 at 24 GHz are obtained as 32.3%, 48.5%, and 50.8%, respectively. The measured beam patterns show that the beam directions are -28.1°, -14.9°, 0°, 15.5°, and 28.6° and the beamwidths are 13.4°, 13.2°, 12.8°, 13.5°, and 13.0°. The measurements confirm that the compact two-layer Rotman lens has been successfully demonstrated. View full abstract»

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  • Bayesian Compressive Sampling for Pattern Synthesis With Maximally Sparse Non-Uniform Linear Arrays

    Page(s): 467 - 481
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    A numerically-efficient technique based on the Bayesian compressive sampling (BCS) for the design of maximally-sparse linear arrays is introduced. The method is based on a probabilistic formulation of the array synthesis and it exploits a fast relevance vector machine (RVM) for the problem solution. The proposed approach allows the design of linear arrangements fitting desired power patterns with a reduced number of non-uniformly spaced active elements. The numerical validation assesses the effectiveness and computational efficiency of the proposed approach as a suitable complement to existing state-of-the-art techniques for the design of sparse arrays. View full abstract»

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  • Synthesis of Multi-Beam Sub-Arrayed Antennas Through an Excitation Matching Strategy

    Page(s): 482 - 492
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    An innovative synthesis procedure to design sub-arrayed antennas affording multiple patterns is presented in this paper. The approach is based on an excitation matching procedure aimed at generating one optimal pattern and multiple compromises close as much as possible to user-defined reference beams. A suitable modification of the K-means clustering algorithm integrated into a customized version of the contiguous partition method is used to efficiently sample the solution space looking for the best compromise excitations. A set of representative numerical results is reported to give some indications on the reliability, potentialities, and limitations of the proposed approach. View full abstract»

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  • Investigations on the Efficiency of Array Fed Coherently Radiating Periodic Structure Beam Forming Networks

    Page(s): 493 - 502
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    The concept of coherently radiating periodic structure beam forming network (C-BFN) has been introduced recently in the literature as a possible mean to feed linear or planar arrays. Losses are expected in such a structure as it produces non-orthogonal excitation laws, motivating the investigations on C-BFN efficiency presented in this paper to guide antenna designers. Mono- and multi-beam applications are considered, including also beam steering capability. These investigations help define some useful design rules depending on the application. Some evolutions are also proposed that may overcome some limitations of the original concept. All the presented results are supported by both simulations and measurements of various prototypes designed on printed technology at 6 GHz. View full abstract»

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  • Design and Implementation of Two-Layer Compact Wideband Butler Matrices in SIW Technology for Ku-Band Applications

    Page(s): 503 - 512
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2295 KB) |  | HTML iconHTML  

    The design and realization of a novel wideband two-layer 4 × 4 Butler matrix in substrate integrated waveguide (SIW) technology are addressed. The two-layer SIW design is exploited through a two-fold enhancement approach. The two-layer topology is first explored in a simple matrix layout with minimum number of components. A space saving design is then proposed making optimum use of the two-layer topology and the SIW technology leading to a significant size reduction. A two-level, low-loss, wideband SIW transition is designed and optimized using its equivalent circuit model. The two corresponding Butler matrix prototypes are optimized, fabricated and measured. Measured and simulated results are in good agreement. Isolation characteristics better than -15 dB with input reflection levels lower than - 12 dB are experimentally validated over 24% frequency bandwidth centered at 12.5 GHz. Measured transmission magnitudes and phases exhibit good dispersive characteristics of 1 dB, around an average value of -6.8 dB, and 10° with respect to the theoretical phase values, respectively, over the entire frequency band. The impact of the measured transmission phases and magnitudes on the radiation pattern of a 4-element antenna array is also investigated. View full abstract»

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  • A Self-Tuning Electromagnetic Shutter

    Page(s): 513 - 519
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    A self-tuning electromagnetic shutter is introduced, consisting of a slotted metallic surface with computer controlled switches placed across the slots. By opening and closing the switches, the transmissivity of the surface may be adjusted over a broad range of frequencies. In particular, the surface may be placed into open and closed states, creating an electronically-controllable shutter. The ability of the shutter to act as an open or a closed surface over a broad range of frequencies, incidence angles, and polarization states is investigated using simulations and measurements, and the feasibility of the system is thereby demonstrated. View full abstract»

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  • Cross-Dipole Bandpass Frequency Selective Surface for Energy-Saving Glass Used in Buildings

    Page(s): 520 - 525
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1008 KB) |  | HTML iconHTML  

    Energy-saving glass is becoming very popular in building design due to their effective shielding of building interior against heat entering the building with infrared (IR) waves. This is obtained by depositing a thin layer of metallic-oxide on the glass surface using special sputtering processes. This layer attenuates IR waves and hence keeps buildings cooler in summer and warmer in winter. However, this resistive coating also attenuates useful microwave/RF signals required for mobile phone, GPS and personal communication systems etc. by as much as 30 dB. To overcome this drawback, a bandpass aperture type cross-dipole frequency selective surface (FSS) is designed and etched in the coatings of energy-saving glass to improve the transmission of useful signals while preserving IR attenuation as much as possible. With this FSS, 15-18 dB peak transmission improvement can be achieved, for waves incident with ±45° from normal for both TE and TM polarizations. Theoretical and measured results are presented. View full abstract»

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  • Multiscale Compressed Block Decomposition for Fast Direct Solution of Method of Moments Linear System

    Page(s): 526 - 536
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    The multiscale compressed block decomposition algorithm (MS-CBD) is presented for highly accelerated direct (non iterative) solution of electromagnetic scattering and radiation problems with the method of moments (MoM). The algorithm is demonstrated to exhibit N2 computational complexity and storage requirements scaling with N1.5, for electrically large objects. Several numerical examples illustrate the efficiency of the method, in particular for problems with multiple excitation vectors. The largest problem presented in this paper is the monostatic RCS of the NASA almond at 50 GHz, for one thousand incidence angles, discretized using 442,089 RWG basis functions. Being entirely algebraic, MS-CBD is independent of the Greens function of the problem. View full abstract»

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  • Electromagnetic Scattering From Electrically Large Arbitrarily-Shaped Conductors Using the Method of Moments and a New Null-Field Generation Technique

    Page(s): 537 - 545
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (576 KB) |  | HTML iconHTML  

    In this work, a new numerical procedure is developed to apply the well-known method of moments (MoM) formulation to electrically large conducting bodies of arbitrary shape. The numerical procedure involves developing a combination of subdomain-entire domain basis functions which result in a sparse moment matrix as opposed to a full matrix in the traditional method. Moreover, the zeros in the MoM matrix are precisely at the same locations where one would have encountered the most significant values. The solution of the new matrix may be obtained using the simple Gauss-Seidel iterative procedure with only two or three iterations. All the traditional advantages of the MoM procedure are retained including the solution for multiple incident fields. Several numerical results are presented to illustrate the validity of the new approach. View full abstract»

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  • Calderon Preconditioned Surface Integral Equations for Composite Objects With Junctions

    Page(s): 546 - 554
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    A Calderon preconditioned (CP) surface integral equation method is developed for the analysis of scattering by piecewise homogeneous dielectric and composite metallic and dielectric objects. The method is based on the electric current formulation (ECF), which only uses the electric surface currents as unknowns. In the ECF the ill-conditioned electric field integral operator and the well-conditioned magnetic field integral operator appear on separate equations, making the application of the CP much easier than e.g., in the PMCHWT formulation where these operators are mixed. In particular, using ECF, Calderon multiplicative preconditioner (CMP) can be straightforwardly extended for composite objects with junctions. Numerical examples demonstrate that the developed formulation, CMP-ECF, is well-conditioned on a very broad frequency range. View full abstract»

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IEEE Transactions on Antennas and Propagation includes theoretical and experimental advances in antennas.

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Meet Our Editors

Editor-in-Chief                                                 Kwok W. Leung