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Antennas and Propagation, IEEE Transactions on

Issue 1 • Date Jan. 2007

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Displaying Results 1 - 25 of 46
  • Table of contents

    Page(s): C1 - 1
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  • IEEE Transactions on Antennas and Propagation publication information

    Page(s): C2
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  • Editorial Stamping Out Duplicate Submission

    Page(s): 2 - 3
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  • Ultrawideband Hybrid EBG/Ferrite Ground Plane for Low-Profile Array Antennas

    Page(s): 4 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1977 KB) |  | HTML iconHTML  

    The design and analysis of an ultrawideband and low-profile hybrid electromagnetic band-gap (EBG)/ferrite ground plane is presented for implementation with antenna systems in airborne foliage penetrating radar and EW applications. The hybrid EBG/ferrite ground plane consists of an EBG structure with a ferrite slab placed on top of the structure's perfect electric conductor (PEC) ground plane. Reflectivity and phase analyses show that the hybrid EBG/ferrite ground plane offers ultrawideband operation beginning in the 100s of MHz with one design version offering an operational bandwidth exceeding 22:1 starting at 170 MHz. Additionally, analysis of the hybrid ground plane implemented with dipole antennas verifies that the hybrid ground plane effectively produces uni-directional radiation for bi-directional radiating antennas. The designed hybrid ground plane is also simulated with Raytheon's long slot array antenna and the obtained results further verify its ultrawideband performance View full abstract»

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  • Subwavelength, Compact, Resonant Patch Antennas Loaded With Metamaterials

    Page(s): 13 - 25
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    We analyze the matching and radiation properties of subwavelength resonant patch antennas filled with double-negative, double-positive, and/or single-negative metamaterial blocks. Analyzing the theoretical limits inherently present when loading such common radiators with metamaterials, we show how these configurations may exhibit in principle an arbitrarily low resonant frequency for a fixed dimension, but they may not necessarily radiate efficiently when their size is electrically small. However, interesting possibilities are suggested to overcome these limitations by employing circular or more complex patch geometries in order to select specific modes that, when appropriate loading ratios between the filling materials are chosen, also ensure radiation performance comparable qualitatively with a regular patch radiator of standard dimensions. Realistic numerical simulations, considering material dispersion, losses and the presence of the antenna feed are presented, showing how a practical realization is foreseeable. This may open novel venues in the design of small-scaled radiators with enhanced performance, which is of interest for many applications View full abstract»

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  • 1-D Scanning Arrays on Dense Dielectrics Using PCS-EBG Technology

    Page(s): 26 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2169 KB) |  | HTML iconHTML  

    We show how the design of integrated arrays can significantly benefit from planar circularly symmetric (PCS) electromagnetic band gap (EBG) structures. Using this technology, a phased array that scans up to 40deg in one dimension and that is characterized by relatively large bandwidth (BWap15%) is designed, manufactured and tested. The specific advantages coming from the use of PCS-EBGs are two fold. On one hand the losses associated to surface waves are significantly reduced. On the other hand each element of the array has a larger effective area that leads to a higher gain for the complete array when compared with a standard technology. Additional benefits are the low cross-polarization levels, the good front to back ratio considering that the antenna does not include a backing reflector, and the low profile View full abstract»

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  • Wideband Antenna Patterns and Impulse Response of Broadband RF Phased Arrays With RF and Photonic Beamforming

    Page(s): 36 - 44
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    The general expression for a monochromatic antenna pattern is extended to a two dimensional function with dependence on both space and time. Expressions for the wideband antenna pattern in space and the impulse response in time are developed. The effects of random errors in the spatial domain and errors common to all elements with fluctuations in the frequency domain are analyzed. Examples are given, including RF beamformers and elements in finite arrays, but with an emphasis on a photonic beamformer, which shows improved performance relative to its RF counterparts in both the spatial and time domains View full abstract»

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  • Design and Modeling of Patch Antenna Printed on Magneto-Dielectric Embedded-Circuit Metasubstrate

    Page(s): 45 - 52
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (907 KB) |  | HTML iconHTML  

    The design and modeling of an embedded-circuit metamaterial with epsi-mu constitutive parameters as the substrate for patch antennas is presented. The magneto-dielectric metasubstrate is constructed of periodic resonant loop circuits embedded in a low dielectric host medium, and is capable of providing both permittivity and permeability material parameters at any frequency of interest. The embedded-circuit building blocks are very small in size (<lambda/20) and constitute artificial material molecules. Geometric control of the embedded-circuits allows epsiv and mu to be tailored to the application. A transmission line circuit model analogy is developed to theoretically investigate the behavior of designed embedded-circuit metamaterial and predict its physical parameters. In addition, a full wave analysis based on finite difference time domain (FDTD) technique is applied to comprehensively characterize the complex periodic structure. The potential advantage of magneto-dielectric metasubstrate for the design of small antennas having relatively wide bandwidth is investigated View full abstract»

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  • Characteristics Verification of a Half-Wave Dipole Very Close to a Conducting Plane With Excellent Impedance Matching

    Page(s): 53 - 58
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (566 KB) |  | HTML iconHTML  

    A half-wave dipole located very close to a conducting plane with distance of lambda/30 is investigated. The configuration has an impedance matching function and a balanced feed built in the antenna structure so that an external matching or a balun is not required. The experimental result verifies the numerical analysis by method of moments (MoM), and well explains the predecessors' analytical results by classical methods. The maximum radiation occurs in the normal direction to a reflector plane. We have achieved a maximum gain of 8.4 dBi which is higher than that of a half-wave dipole with a quarter wavelength distance between the reflector. The bandwidth for -10 dB is about 2%. The electric field distribution is studied to show the creation and propagation of electromagnetic waves which correspond to the energy flows in the normal direction to the conductor plane and also sideward along the plane in a small amount. The field lines are shown to be frozen between the dipole and the conductor plane without propagation. Accordingly, this state may be called a quadruple mode View full abstract»

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  • Sidelobes Due to Periodic Amplitude and Phase Errors in the Aperture Field of a Radial Waveguide Pin-Fed Array Antenna

    Page(s): 59 - 64
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    The location and level of the sidelobes of a radial waveguide pin-fed array antenna, which stem from periodic amplitude and phase errors in the actual antenna aperture field, are derived based on a simple model of a line source as well as the pertinent model of a circular aperture. The theoretical results are verified by comparisons with numerical and measured data View full abstract»

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  • A Tunable Via-Patch Loaded PIFA With Size Reduction

    Page(s): 65 - 71
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (741 KB) |  | HTML iconHTML  

    A novel tunable planar inverted-F antenna (PIFA) is described. A via-patch is introduced under the main radiating element to create a capacitive coupling effect and lower the operating frequency. The antenna size is reduced by half when compared to the conventional PIFA. Incorporating with an L-shaped opening on the ground plane, the proposed via-patch loaded PIFA exhibits a 10-dB return-loss bandwidth of 8.91% for 2.4 GHz ISM band applications. In the proposed approach, the capacitive patch is connected to the ground through a via while a coaxial feed is directly connected to the radiating element. This is different from other capacitive-loading, size-reduction schemes in which the capacitive patch is connected to the coaxial feed, thus not able to provide frequency tuning. By simply replacing the via in our antenna with a screw and adjusting the height of the via-patch by turning the screw, a tuning range of 0.8 GHz from 2.5-3.3 GHz can be achieved. This makes the proposed PIFA a convenient tunable small antenna. Both simulation and measurement results are presented together with parametric studies on the via-patch and L-shaped opening ground plane View full abstract»

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  • Small Low-Profile Loop Wideband Antennas With Unidirectional Radiation Characteristics

    Page(s): 72 - 77
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (627 KB) |  | HTML iconHTML  

    Small low-profile wideband loop antennas featuring unidirectional radiation characteristics are presented. Directive radiation characteristic is achieved by proper combination of fields radiated by symmetric and anti-symmetric current components supported by any loop antenna. Relative strengths of the symmetric and the anti-symmetric radiations change according to shape of the loop. Prototype loop antennas are fabricated and their impedance and radiation gain patterns are measured. The gain patterns show directive characteristics in both major planes. It is shown that the gain measured in the desired direction of maximum radiation exceeds the maximum achievable practical gain for omnidirectional antennas of the same dimensions over wide frequency band View full abstract»

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  • Wideband Dual-Polarized Patch Antenna With Broadband Baluns

    Page(s): 78 - 83
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    A pair of novel 180deg broadband microstrip baluns are used to feed a dual-polarized patch antenna. The 180deg broadband balun delivers equal amplitude power division and consistent 180deg (plusmn5deg) phase shifting over a wide bandwidth (>50%). We demonstrate that for a dual-polarized quadruple L-probe square patch antenna, the use of the proposed 180deg broadband balun pair, in place of a conventional 180deg narrowband balun pair, provides improved input port isolation and reduced H-plane cross-polarization levels over a wider frequency range, while maintaining low E-plane cross-polarization levels and stable E- and H-plane co-polarization patterns throughout the impedance passband View full abstract»

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  • Ultrawideband Double Rhombus Antenna With Stable Radiation Patterns for Phased Array Applications

    Page(s): 84 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2123 KB) |  | HTML iconHTML  

    A broadband microstrip-fed printed antenna is proposed for phased antenna array systems. The antenna consists of two parallel-modified dipoles of different lengths. The regular dipole shape is modified to a quasi-rhombus shape by adding two triangular patches. Using two dipoles helps maintain stable radiation patterns close to their resonance frequencies. A modified array configuration is proposed to further enhance the antenna radiation characteristics and usable bandwidth. Scanning capabilities are studied for a four-element array. The proposed antenna provides endfire radiation patterns with high gain, high front-to-back (F-to-B) ratio, low cross-polarization level, wide beamwidth, and wide scanning angles in a wide bandwidth of 103% View full abstract»

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  • Filtenna Consisting of Horn Antenna and Substrate Integrated Waveguide Cavity FSS

    Page(s): 92 - 98
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    An integrated module with filtering and radiation performance realized by covering substrate integrated waveguide (SIW) cavity frequency selective surface (FSS) at aperture of horn antenna has been investigated in this paper. The module has functions of bandpass filter and horn antenna, so it is called a "filtering antenna" (filtenna). It is very suitable for applications in military platforms where FSS is used for antennas and radars' radar cross section (RCS) reduction. The filtenna is simulated and optimized with CST software and its performance is verified by experiments. From simulated and measured results it can be found that the proposed structure keeps characteristics of return loss, radiation pattern and gain of the horn antenna within desired frequency band, meanwhile presents effective reflection to interference signals at out-band. Using this structure the volume and cost of communication systems in military platforms can be effectively reduced View full abstract»

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  • GO Shaping of Omnidirectional Dual-Reflector Antennas for a Prescribed Equi-Phase Aperture Field Distribution

    Page(s): 99 - 106
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    A formulation is presented for shaping dual-reflector antennas designed to offer an omnidirectional coverage. The shaping procedure is based on geometrical optics (GO) principles and assumes a uniform phase distribution for the aperture field. Two distinct dual-reflector arrangements, based on the axis-displaced Cassegrain (ADC) and ellipse (ADE) configurations, are investigated. The GO shaping results are validated using the accurate analysis provided by the method-of-moments technique View full abstract»

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  • Radiation of a Leaky Coaxial Cable With Narrow Transverse Slots

    Page(s): 107 - 110
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    The problem of a leaky coaxial cable with narrow transverse slots is solved by using the Fourier transform and mode-matching techniques. The characteristics of far-field radiation and near-field coupling are presented in terms of numerically fast convergent series. Our theoretical results are compared with experimental data to confirm favorable agreement View full abstract»

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  • Analysis of an Electromagnetic Field Created by Line Current Using Constrained Interpolation Profile Method

    Page(s): 111 - 119
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    Development of accurate schemes is a technical issue related to calculation of electromagnetic fields. This study uses constrained interpolation profile (CIP) method to analyze electromagnetic fields created by line current. This is a novel method proposed by Yabe. Comparison of results obtained using finite difference time domain (FDTD) analysis and CIP analysis indicates that CIP analysis provides higher accuracy using identical discretization. In addition, given the same level of accuracy, CIP analysis requires less memory and less calculation time View full abstract»

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  • Analysis and Regularization of the Thin-Wire Integral Equation With Reduced Kernel

    Page(s): 120 - 129
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    For the straight wire, modeled as a hollow tube, we establish a conditional equivalence relation between the integral equations with exact and reduced kernel. This relation allows us to examine the existence and uniqueness conditions for the integral equation with reduced kernel, based on a local argument. Further, we characterize the ill-posedness of integral equation with reduced kernel and we propose a regularization and filtering procedure to extend the range of this integral equation View full abstract»

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  • Wave-Field Interaction With Complex Structures Using Equivalence Principle Algorithm

    Page(s): 130 - 138
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    A domain decomposition scheme based on the equivalence principle, similar to Huygens' principle, for integral equation solvers and the method of moments is introduced. The equivalence principle allows the replacement of unknown currents distributed in a volume in space by equivalence currents residing on the surface that bounds the volume. It also allows the dissociation of the solution of one region from that of another region. In this manner, problems of high complexity can be encapsulated by surfaces of simpler shapes using less unknowns. It can aid in parallel algorithms, reusability of solutions, as well as improving the condition number of a matrix system when disparate mesh or adaptive mesh are needed. The challenge arises when an equivalence surface intercepts a current-carrying conductor, because the breakup of the current into separate pieces gives rise to charge singularity. A junction basis can be used to mitigate this singularity. However, a better solution is to introduce a tap basis to model the current that intercepts with the equivalence surfaces. Using this scheme, the current continuity is conserved and the singularity of the charges is avoided. The solution is shown to be accurate View full abstract»

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  • An Optimization of a Voltage Pulse Excitation in a UWB Radio System

    Page(s): 139 - 142
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    The parameter energy link loss between the source of the transmitter and the load of the receiver is used to evaluate the performance of a ultrawideband (UWB) radio system. The rigorous calculation of the link loss in a UWB system requires a complicated full transient solution for the transmit and receive antennas. However, after involving suitable approximations, the optimization problem is converted to finding a maximum generalized eigenvalue problem. For the special cases of two similar small antennas (dipoles and loops), an analytical method for calculation of the elements of both matrices is developed. These expressions are derived assuming that the receiver load resistance is given, while the transmitter voltage excitation is represented in terms of an orthonormal system of Gauss-Hermite pulses. Appropriate numerical results are presented for two short dipoles and two small loops View full abstract»

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  • Measurement and Modelling of Scattering From Buildings

    Page(s): 143 - 153
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    The results of a measurement campaign aimed at determining the far-field diffuse scattering pattern of typical building walls are shown in the paper. Such results are then used to determine and tune simple diffuse scattering models based on the effective roughness approach, to be embedded into ray tracing simulators. It is shown that by adopting an appropriate single-lobe scattering pattern the agreement between simulation and measurement is very good View full abstract»

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  • Fast Numerical Analysis of Infinite Helix Layers

    Page(s): 154 - 161
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    The scattering of particles is described by multipole moments up to the electric quadrupole contribution. A method for the calculation of reflection and transmission from thin composite layers is derived. The approach uses periodic boundary conditions. The validity of the approach is checked by considering thin chiral layers composed of small metal helices. The investigations are performed in the frequency domain and include the resonance case View full abstract»

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  • AIM Analysis of Scattering and Radiation by Arbitrary Surface-Wire Configurations

    Page(s): 162 - 166
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1058 KB) |  | HTML iconHTML  

    The adaptive integral method is utilized to solve electromagnetic scattering and radiation problems of conducting surface-wire configurations. The method of moments (MoM) is applied to establish the integral equations where triangular type basis functions are used to represent the currents on surfaces and wires. Attachment mode has been used to model the surface-wire junction to ensure the current continuity. The resultant matrix system is then solved by an iterative solver where the adaptive integral method (AIM) is employed to reduce memory requirements and to accelerate the matrix-vector multiplications. Numerical results are presented to demonstrate the accuracy and efficiency of the present technique for the arbitrary surface-wire configurations View full abstract»

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  • Efficient Calculation of Interior Scattering From Large Three-Dimensional PEC Cavities

    Page(s): 167 - 177
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    Higher order finite element-boundary integral (FE-BI) method is a powerful tool to model the electromagnetic (EM) scattering from three-dimensional large, deep, and arbitrarily-shaped cavities. To further understand the higher order FE-BI method and its applications to the modeling of interior scattering from very large practical perfect electric conductor (PEC) cavity structures, two aspects will be discussed in this paper. The first is on the development of a new integration method to accurately handle singular integrals in calculating BI matrix elements resulted from higher order basis functions defined on higher order elements. The second is on the numerical and experimental verifications of the higher order FE-BI code developed and its applications to the study of the effects of cavity shape, termination and aperture coupling on the interior scattering from large PEC cavities View full abstract»

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Aims & Scope

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