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Antennas and Wireless Propagation Letters, IEEE

Date 2008

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Displaying Results 1 - 25 of 216
  • Table of contents

    Page(s): C1 - 846
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  • IEEE Antennas and Wireless Propagation Letters publication information

    Page(s): C2
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  • Wideband and Dual-Band Design of a Printed Dipole Antenna

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (673 KB) |  | HTML iconHTML  

    A wideband and dual-band dipole antenna with an integrated balun feed is given. First, the antenna structure is optimized and a 41.5% bandwidth is obtained where voltage standing wave ratio (VSWR) is less than 2. In order to further get a larger bandwidth and dual-band capabilities of this antenna, some rectangle apertures are etched onto the antenna surface, and a better dipole antenna is fabricated. Through investigating rectangle aperture with different sizes, a 47.8% bandwidth is obtained at L-band, and a 15.1% bandwidth comes true at S-band. Agreement between calculations and measurements is very good. The result indicates that the novel design not only may obtain better wideband characteristic but also can let the dipole antenna work at L- and S-bands. View full abstract»

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  • Meandered-Slot Antennas for Sensor-RFID Tags

    Page(s): 5 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (718 KB) |  | HTML iconHTML  

    This letter introduces a planar antenna layout suited to sensor-RFID fabrication. The geometry is based on a meandered-slot profile on a suspended patch and permits to host sensors and electronics in a small space. The available geometrical parameters are optimized by means of a genetic algorithm (GA) procedure aimed to maximize the antenna realized gain. The antenna performances are discussed through examples and prototypes. View full abstract»

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  • A Single Layer Wideband U-Slot Microstrip Patch Antenna Array

    Page(s): 9 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (702 KB) |  | HTML iconHTML  

    The design and measured results of a 2 times 2 microstrip line fed U-slot rectangular antenna array are presented. The U-slot patches and the feeding network are placed on the same layer, resulting in a very simple structure. The advantage of the microstrip line fed U-slot patch is that it is easy to form the array. An impedance bandwidth (VSWR < 2) of 18% ranging from 5.65 GHz to 6.78 GHz is achieved. The radiation performance including radiation pattern, cross polarization, and gain is also satisfactory within this bandwidth. The measured peak gain of the array is 11.5 dBi. The agreement between simulated results and the measurement ones is good. The 2 times 2 array may be used as a module to form larger array. View full abstract»

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  • Negative Permeability-Based Electrically Small Antennas

    Page(s): 13 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (661 KB) |  | HTML iconHTML  

    The goal of this letter is to present the behavior of mu-negative (MNG) metamaterial-based electrically small antennas. The Green's function analysis is applied to characterize the performance of a hemispherical negative permeability (MNG) resonator excited by a slot aperture. The method of moment (MoM) is used to obtain the current distribution over the source excitation. It is illustrated how a resonator composed of negative permeability medium can successfully establish a small antenna element. For small-size structure , the approximated-form Green's function demonstrates the relation between the resonant frequencies and the material parameters. The obtained results are integrated into the design of a MNG slab radiator. The radiation performance of a slab resonator is detailed using a finite difference time domain (FDTD) full wave analysis. The obtained observations may provide road maps for the future design of metamaterial-based subwavelength antennas. View full abstract»

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  • Printed Slot Planar Inverted Cone Antenna for Ultrawideband Applications

    Page(s): 18 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    A novel ultrawideband (UWB) printed wide-slot antenna is presented. The design is based on the planar inverted cone antenna (PICA), introduced by Suh. The presented design comprises PICA-like structures, etched from a double-layer substrate. Compared to the original PICA, it is lower in profile, more compact and maintains comparable performance. A prototype integrated in a printed circuit board and fed by a microstrip line is fabricated and measured. The results show that the proposed antenna provides at least 13:1 impedance bandwidth at 10-dB return loss. View full abstract»

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  • Size Reduction of a Low-Profile Spiral Antenna Using Inductive and Dielectric Loading

    Page(s): 22 - 25
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (574 KB) |  | HTML iconHTML  

    This letter discusses a miniature low profile ultrawideband (UWB) spiral. The antenna is miniaturized using a combination of dielectric and inductive loading. In addition, a ferrite coated ground plane is adopted in place of the traditional metallic ground plane for profile reduction. Using full-wave simulations and measurements, it is shown that the miniaturized spiral can achieve similar performance to a traditional planar spiral twice its size. View full abstract»

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  • Artificial Neural Network and Analytical Method-Based Control of Higher Harmonic Radiation From Active Antenna Arrays

    Page(s): 26 - 30
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (510 KB) |  | HTML iconHTML  

    The mean-square error (MSE) criterion combined with the Lagrange method and an artificial neural network (ANN) technique are proposed for the reduction of the radiation of the higher harmonic signals generated in active antenna arrays. View full abstract»

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  • Accurate Design Method for Pyramidal Horns of Any Desired Gain and Aperture Phase Error

    Page(s): 31 - 32
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (72 KB) |  | HTML iconHTML  

    An exact solution is presented for the fourth-order polynomial representing the general horn design problem. When the available approximations are used for the gain reduction factors, this leads to closed-form expressions for the aperture, and hence the other, dimensions of the pyramidal horn of any desired gain and aperture phase error. View full abstract»

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  • Analytical Approach to the Backscattering from UHF RFID Transponder

    Page(s): 33 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB) |  | HTML iconHTML  

    The investigation of the modulated, backscattered contribution from UHF RFID Transponders is a crucial issue for the reliable evaluation of the behavior and the performance of RFID systems. The backscattered, radiated field by a UHF Transponder is described by means of a simple and complete analytical expression. The tag radar cross section (RCS) and the bit error rate (BER) at the Reader are evaluated by means of the achieved formula, and the results are in perfect agreement with previous available publications. View full abstract»

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  • Efficient Solution of the Electric-Field Integral Equation Using the Iterative LSQR Algorithm

    Page(s): 36 - 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (490 KB) |  | HTML iconHTML  

    In this letter, we consider iterative solutions of the three-dimensional electromagnetic scattering problems formulated by surface integral equations. We show that solutions of the electric-field integral equation (EFIE) can be improved by employing an iterative least-squares QR (LSQR) algorithm. Compared to many other Krylov subspace methods, LSQR provides faster convergence and it becomes an alternative choice to the time-efficient no-restart generalized minimal residual (GMRES) algorithm that requires large amounts of memory. Improvements obtained with the LSQR algorithm become significant for the solution of large-scale problems involving open surfaces that must be formulated using EFIE, which leads to matrix equations that are usually difficult to solve iteratively, even when the matrix-vector multiplications are accelerated via the multilevel fast multipole algorithm. View full abstract»

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  • A Widely Tunable Compact Patch Antenna

    Page(s): 40 - 42
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (213 KB) |  | HTML iconHTML  

    In this letter, we propose a tunable patch antenna made of a slotted rectangular patch loaded by a number of posts close to the patch edge. The posts are short circuited to the ground plane via a set of PIN diode switches. Simulations and measurements verify the possibility of tuning the antenna in subbands from 620 to 1150 MHz. Good matching has been achieved over most of the bands. Other performed designs show that more than one octave can be achieved using the proposed structure. View full abstract»

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  • Accurate Representation of the Edge Behavior of Current When Using PO-Derived Characteristic Basis Functions

    Page(s): 43 - 45
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (122 KB) |  | HTML iconHTML  

    A procedure for accurate solution of scattering problems involving geometries with sharp edges by using physical optics-based characteristic basis functions, which themselves do not possess edge singularities, is presented in this communication. Our strategy is to employ special types of blocks that contain the free edges of the object, within which we can accurately represent the behaviors of the currents with rapidly varying amplitudes, still by using physical optics (PO)-types functions for the initial bases. The set of geometrical blocks which are associated solely with the edges extend along each edge, but have a relatively small width. The final number of characteristic basis functions using this approach is only slightly greater than that needed in the conventional characteristic basis function method (CBFM), which does not utilize the edge-block strategy. However, the accuracy in the final results is notably improved in some cases. View full abstract»

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  • On the Relationship Between the Time-Domain and Frequency-Domain TLM Methods

    Page(s): 46 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (101 KB) |  | HTML iconHTML  

    The time- and frequency-domain transmission line matrix (TLM) methods have been developed and shown to be effective and powerful in solving electromagnetic problems. However, their direct relationship has not been clearly described so far. In this letter, we show that if a time-domain TLM method is developed, its corresponding frequency-domain counterpart can also be obtained through the discrete time Fourier transform; in a similar manner, if a frequency-domain TLM method is developed, its time-domain counterpart can also be obtained through the inverse discrete time Fourier transform. The choice of using the frequency- or time-domain depends very much on the types of the problems to be solved and the familiarity of a user with the methods. View full abstract»

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  • Unidirectional Antenna With Loaded Dielectric Substrate

    Page(s): 50 - 53
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (345 KB) |  | HTML iconHTML  

    A unidirectional antenna with loaded dielectric substrate composed of two shorted-circuited rectangular patches and a printed Gamma-shaped probe feed operated at 2.5 GHz is presented. The antenna is fully filled with dielectric substrate isinr = 2.65. The height of the antenna is only 18 mm. A wide impedance bandwidth of 45.3% (SWR les 2) is achieved. The average gain is about 6.7 dBi. The antenna performance can be improved by introducing of a metallic wall. The backlobe is reduced from -11.1 to -20.1 dB at the lower frequency. View full abstract»

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  • Aperiodic-Tiling-Based Mushroom-Type High-Impedance Surfaces

    Page(s): 54 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (769 KB) |  | HTML iconHTML  

    This letter deals with a study of aperiodically ordered textured (mushroom-type) high-impedance surfaces (HISs), and their possible application as artificial-magnetic-conductor ground-planes for low-profile directive antennas. In this framework, results from full-wave simulations are presented in order to characterize the electromagnetic response (in terms of impedance matching, directivity, and surface-wave suppression) of selected configurations based on representative categories of aperiodic tilings, and compare them with those of standard periodic HISs. View full abstract»

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  • Characteristics Estimation for Jerusalem Cross-Based Artificial Magnetic Conductors

    Page(s): 58 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB) |  | HTML iconHTML  

    This letter proposes a circuit model capable of predicting the bandwidth and resonance frequency of a well-known artificial magnetic conductor (AMC). The AMC is composed of an array of Jerusalem cross-shaped frequency selective surfaces (FSSs) (JC-FSS) deployed on a thin PEC-backed dielectric slab. The model benefits from the static (Quasi-TEM) closed-form equations, available in literature for the characteristic impedance of microstrip transmission lines. These equations enable the model to incorporate the influences of the slab thickness on the FSS impedance, a feature that the available models have not been able to offer exactly. In order to check the competence of the model, some sample AMCs are designed by the model, and their properties are verified by numerical analysis. View full abstract»

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  • Low-Profile Loop-Shaped Inverted-F Wire Antenna With Dual-Mode Operation

    Page(s): 62 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (812 KB) |  | HTML iconHTML  

    In this letter, we propose a new structure for a dual-mode antenna. We introduce a loop-shaped inverted-F wire antenna (LIFA) that has small and low-profile structure and uses a parasitic element (PE) within the feeding element for the additional resonance mode. We present a theoretical discussion on the dual-resonance operation and investigate the characteristics along some dimensional parameters using numerical analyses. The measurement results with the proposed structure are also presented. View full abstract»

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  • The \kappa -\mu Distribution Applied to the Analysis of Fading in Body to Body Communication Channels for Fire and Rescue Personnel

    Page(s): 66 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (674 KB) |  | HTML iconHTML  

    In this letter, we perform a novel characterization of the fading experienced in body to body communications channels for fire and rescue personnel using the recently proposed kappa - mu distribution. A transmitter positioned on the lead fire person and four strategically placed, time-synchronized 2.45-GHz receivers situated on the protective helmet and shoulders of another team member allowed small-scale signal variation to be recorded while a rescue team of four persons performed a building sweep and search type operation. A general kappa - mu model with parameters kappa=2.31 and mu=1.19 was obtained using maximum likelihood estimation and shown to provide a good fit to measured data. Level crossing rates for these channels are also presented. View full abstract»

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  • Computation of the Physical Optics Integral on NURBS Surfaces Using a Radon Transform Interpretation

    Page(s): 70 - 73
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (473 KB) |  | HTML iconHTML  

    Physical optics (PO) requires the calculation of a surface integral on a structure, which can be called as the PO integral. The surface of most structures can be accurately represented by nonuniform rational B-spline (NURBS) surfaces. In this letter, the PO integral over NURBS surfaces is reduced to an exact line integral by using a Radon transform (RT) interpretation. The integration line is shown to be the time-dependent intersection line of the NURBS surface of interest with a plane determined by the illumination and observation directions. Hence, the accuracy of evaluating the PO integral is limited only by the geometrical evaluations involving the NURBS surfaces. The accuracy of the derived closed form expression is demonstrated through numerical examples. View full abstract»

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  • Effective Propagation Properties of an Enhanced Hybrid EBG/Ferrite Ground Plane

    Page(s): 74 - 77
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    An enhanced ultrawideband and low-profile hybrid electromagnetic bandgap (EBG)/ferrite ground plane design is presented that offers an increased bandwidth and reduced profile compared to the previously presented hybrid EBG/ferrite ground plane design. Reflectivity and phase analyses of the new hybrid ground plane design indicate an instantaneous and continuous operational bandwidth exceeding 40:1 beginning at 120 MHz. The effective complex permittivity and permeability of the hybrid ground plane, which are important for feed design considerations of certain phased array antenna systems, are also presented. Additionally, return loss and directive gain analyses of Raytheon's long slot array antenna implemented with the hybrid ground plane further verify the ability of the ground plane to provide ultrawideband unidirectional radiation characteristics for ultra- wideband bidirectional radiating antennas. View full abstract»

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  • Simple and Accurate Two-Dimensional Angle Estimation for a Single Source With Uniform Circular Array

    Page(s): 78 - 80
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (202 KB) |  | HTML iconHTML  

    A least squares algorithm for two-dimensional (2-D) angle estimation of a single narrowband source impinging on a uniform circular array (UCA) is presented. Utilizing the centrosymmetric array configuration, a new correlation-based method is devised to obtain closed-form estimates of the azimuth and elevation angles. Although the proposed method is computationally simpler than the conventional schemes, computer simulations show that it can approach optimum estimation performance. View full abstract»

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  • A Low-Cost Patch Antenna Phased Array With Analog Beam Steering Using Mutual Coupling and Reactive Loading

    Page(s): 81 - 84
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (167 KB) |  | HTML iconHTML  

    In this letter, a low-cost patch antenna phased array is demonstrated with analog beam steering without using phase shifters. This novel technique can greatly reduce the cost of a phased-array system and will enable the wide-scale deployment of phased arrays in low-end commercial products. In the presented three-element phased array, the center (driven) antenna is fed by an RF source and the two neighboring (passive) antennas are excited through the mutual coupling from the center antenna. The phase shifts between the antenna elements are achieved by changing the reactance of the capacitors loading the two passive antennas. A phased array using this novel technique is designed, fabricated, and measured at 3 GHz with a bandwidth of 1.8%. This phased array is shown to be able to steer the antenna beam from 20 to 20 degrees in an analog fashion. The measured radiation patterns of this phased array closely match the theoretical calculation and full-wave simulation results. View full abstract»

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  • Half-Mode Substrate Integrated Waveguide (HMSIW) Leaky-Wave Antenna for Millimeter-Wave Applications

    Page(s): 85 - 88
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (630 KB) |  | HTML iconHTML  

    A novel leaky-wave antenna is demonstrated and developed at Ka-band in this work based on the newly proposed half-mode substrate integrated waveguide (HWSIW). This antenna is accurately simulated by using a full-wave electromagnetic simulator and then fabricated through a single-layer printed circuit board (PCB) process. Wide bandwidth and a quasi-omnidirectional radiation pattern are obtained. The proposed antenna is therefore a good candidate for millimeter-wave applications. Measured results are in good agreement with simulated results. View full abstract»

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Aims & Scope

IEEE Antennas and Wireless Propagation Letters is devoted to the rapid electronic publication of short manuscripts in the technical areas of Antennas and Wireless Propagation.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Yang Hao
School of Electronic Engineering and Computer Science
Queen Mary College, University of London