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Antennas and Propagation, IEEE Transactions on

Issue 7 • Date July 2008

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Displaying Results 1 - 25 of 47
  • Table of contents

    Publication Year: 2008 , Page(s): C1 - C4
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  • IEEE Transactions on Antennas and Propagation publication information

    Publication Year: 2008 , Page(s): C2
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  • Study of Mutual Coupling Between Circular Stacked-Patch Antennas on a Sphere

    Publication Year: 2008 , Page(s): 1834 - 1844
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1378 KB) |  | HTML iconHTML  

    A rigorous mathematical analysis is given of spherical stacked-patch arrays with emphasis on the physical interpretation of mutual coupling mechanisms present in doubly- curved convex structures. The analysis method is based on electromagnetic field representation in terms of spherical harmonics where each harmonic has the same angular variation as the spectral source component. To obtain the spectral representation the vector-Legendre transformation is applied to currents and fields. A novel approach to the mutual coupling calculation within the method of moments analysis of spherical arrays is applied. By expressing the patch current in terms of two suitable potential-like auxiliary functions, it is possible to avoid the use of Euler's formulas for coordinate system rotation and the related lengthy integrations. Instead, the rotation of antenna elements and corresponding current distributions can be done in closed form with the help of Vilenkin's addition theorem for associated Legendre functions. It is shown that the new approach results in significant acceleration and improved accuracy of the analysis of spherical patch antenna arrays. The algorithm is successfully tested against a commercially available electromagnetic software and measurements performed on the developed laboratory model, confirming its accuracy for both input impedance and mutual coupling calculation and with only a small difference between the predicted and measured resonant frequencies, due to limitations in the experimental model. The influence of the structure parameters on mutual coupling level is extensively investigated, including all coupling mechanisms and leakage of energy due to curvature of the structure. It is shown that stacked-patch antennas can have reduced coupling level comparing to single patch antennas with possible deep nulls above the antenna resonant frequency. View full abstract»

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  • Design of a Single-Feed Dual-Band Dual-Polarized Printed Microstrip Antenna Using a Boolean Particle Swarm Optimization

    Publication Year: 2008 , Page(s): 1845 - 1852
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (866 KB) |  | HTML iconHTML  

    A novel dual-frequency dual-linear-polarization printed antenna element benefiting from a single-feed single-layer structure is introduced in this paper. The Boolean particle swarm optimization algorithm in conjunction with the method of moments (MoM) is employed to optimize the geometry of the antenna after considering three objectives: cross polarization, return loss, and boresight direction in both bands. A fuzzy-logic based ordered weighted averaging operator allows us to efficiently implement the multi-objective optimization technique. Prototypes of the optimized designs have been fabricated and tested. The measured results show excellent performance with more than 15 dB of return loss and 10 dB of cross polarization in both frequency bands of operation, i.e., 12 and 14 GHz. A gain of 4.8 dBi has been measured for both frequency bands. View full abstract»

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  • Characterization and Design of Cylindrical Microstrip Leaky-Wave Antennas

    Publication Year: 2008 , Page(s): 1853 - 1859
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (985 KB) |  | HTML iconHTML  

    The spectral-domain approach is applied for the analysis and the design of the cylindrical microstrip leaky-wave antenna. The first higher-order leaky-mode is thoroughly investigated. We perform the well-known spectral-domain approach and Galerkin's method to acquire the complex propagation constants of leaky modes, which are verified with results obtained by the scattering-parameter extraction technique. Two practical antennas are designed and implemented. Measured return loss and radiation patterns show a good performance of these cylindrical antennas, compared to that of the planar ones. View full abstract»

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  • New Proximity Coupled Feeding Method for Reconfigurable Circularly Polarized Microstrip Ring Antennas

    Publication Year: 2008 , Page(s): 1860 - 1866
    Cited by:  Papers (33)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (670 KB) |  | HTML iconHTML  

    A new simple single-feed method for circularly polarized ring antennas has been investigated. Experimental and theoretical investigation show that either right-handed (RH) or left-handed (LP) circular polarization (CP) can be easily achieved by selecting one of the two input ports of the antennas. The proposed U-shaped microstrip feed line excites the fundamental TM11 mode of the ring radiating elements through proximity coupling along the semi-annular section of the line. The induced rotating surface currents on the ring radiators contribute to the circular polarization behavior of the antennas. Two types of rings have been investigated. Square ring prototypes operate at 2.7 GHz have been designed, fabricated and evaluated to show the basic operating principles of the antennas, while annular ring radiating elements operate at 2.255 GHz are realized to demonstrate the reconfigurable capability of the new feeding structure. In the reconfigurable design, a high isolation RF switch is used to direct the input signal between the two input ports. With suitable biasing arrangement of the RF switch, the antenna is capable to radiate at either types of circular polarization. The reconfigurable design is fed by a single microstrip line. Return losses, axial ratios, gains and radiation patterns of the prototype antennas have been measured for verifications. A parametric study of the new feeding structures with a square ring has been carried out for important design guidelines. View full abstract»

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  • On the Characteristics of Radome Enclosed Archimedean Spiral Antennas

    Publication Year: 2008 , Page(s): 1867 - 1874
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB) |  | HTML iconHTML  

    The effects of the superspheroidal radomes on the characteristics of Archimedean spiral antennas are investigated in detail, which may provide some useful insights in the design of the radome-antenna system in practical engineering. All interactions between the radome and antennas are rigorously included in the coupled surface integral equation (CSIE) model, which leads to more accurate results than those of the existing methods based on the high-frequency algorithm or the decoupled radome-antenna analysis procedure especially when the antennas are placed in the close proximity of the radome. Numerical results show that the performance of the spiral antenna is significantly changed due to the presence of the radome. View full abstract»

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  • Design Optimization of UWB Printed Antenna for Omnidirectional Pulse Radiation

    Publication Year: 2008 , Page(s): 1875 - 1881
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1046 KB) |  | HTML iconHTML  

    The use of ultrawideband technology in many applications implies the use of a suitable radiating structure, especially for pulsed systems. The development of a triangular CPW-fed printed antenna with specific ground plane shape is presented. First the triangular element was optimized to minimize return losses and size of the antenna in the [3.1-10.6] frequency band. The evolution of radiation patterns with frequency was also studied, as changes in phase center position and radiation characteristics alter the integrity of transmitted pulses. Thus the antenna ground plane shape was modified in order to maintain almost constant radiation patterns over the entire bandwidth. Time domain measurement methods were used to characterize the antennas and validate these improvements. The procedure is presented and results are plotted in a 3D format and discussed. View full abstract»

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  • Naval Structural Antenna Systems for Broadband HF Communications—Part III: Experimental Evaluation on Scaled Prototypes

    Publication Year: 2008 , Page(s): 1882 - 1887
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1848 KB) |  | HTML iconHTML  

    We describe the design, fabrication and measurement of reduced-size prototypes of the naval structural antenna, recently proposed as a compact and multifunction solution to broadband naval communications. The original broadband HF sub-radiator, loaded by lumped impedances, is scaled down to the VHF/UHF ranges and re-designed in planar technology in order to simplify and to automate the fabrication process. Measurement on single-port and 4-port antennas, in which the central structure resembles a naval funnel and a big mast, have shown a good agreement with the simulations. View full abstract»

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  • Fast Measurement Technique for Phased Array Calibration

    Publication Year: 2008 , Page(s): 1888 - 1899
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1370 KB) |  | HTML iconHTML  

    A novel measurement method is proposed in order to measure the active electric fields of the individual antenna elements in a phased array antenna. Fast and accurate measurements can be realized by the proposed method because the electric fields of multiple elements can be obtained simultaneously and no phase measurements are required. Hence, it can be easily applied to the on-board diagnostics and re-calibration in the operating phased array antenna systems. In the first step with this method, the phases of multiple antenna elements are successively shifted with the specified phase intervals while the array power variations are measured. Next, the measured power variation is expanded into a Fourier series and the terms are rearranged to put them into the form of the rotating element electric field vector (REV) method. Finally, the REV solution is used to identify the electric fields of the individual elements. Additionally, a theoretical study is carried out on the accuracy of the proposed measurement method. Simple, closed-form equations have been successfully derived for the measurement errors and the calibration accuracy is theoretically estimated. The proposed measurement method is validated with experimental results and the measurement accuracy is compared with the theoretical prediction. View full abstract»

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  • Ultrawideband Antenna Distortion Compensation

    Publication Year: 2008 , Page(s): 1900 - 1907
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2111 KB) |  | HTML iconHTML  

    The radiation characteristics of ultrawideband (UWB) antennas vary with frequency, introducing directionally asymmetric bandwidth reduction and waveform dispersion. In this paper, we develop a simple technique to alleviate the distortion due to nonisotropically dispersive antennas, and use indoor channel measurements to verify its performance. The approach is based on multipath direction estimation and therefore involves antenna arrays. We show that antenna distortion can enhance sensor localization ambiguity and introduce errors in its estimate. Antenna compensation mitigates this effect, significantly improving the location estimation accuracy. We further demonstrate that antenna compensation helps reduce the small-scale fading artifacts that arise due to the antennas, thus reducing the channel spatial variability and delay spread. Our technique can also aid empirical channel characterization by providing antenna-independent propagation data. View full abstract»

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  • Aperture-Sparsity Analysis of Ultrawideband Two-Dimensional Focused Array

    Publication Year: 2008 , Page(s): 1908 - 1918
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB) |  | HTML iconHTML  

    We investigate the effects of aperture sparsity on the focusing performance and the angular-resolution capability of a two-dimensional focused array antenna excited by ultrawideband (UWB) impulse waveforms. The UWB-focusing array is characterized by a planar square aperture and a design parameter referred to as array spatial bandwidth. Spatial bandwidth is a function of the number of array elements, inter-element spacing, and frequency bandwidth. Performance analysis is carried out by generating computer plots of three-dimensional and two-dimensional antenna patterns for different values of array spatial bandwidth that hold for large aperture sparsity and large aperture density. The antenna patterns are peak-amplitude pattern, peak-power pattern, and energy pattern, whose narrow beamwidth and low sidelobe level are robust against aperture sparsity that may be caused by removed or failed elements. The half-power beamwidth (HPBW) of the antenna patterns, the focal distance, and the far-field distance of the UWB-focused array are expressed in terms of array spatial bandwidth. Computer simulation results show that UWB-focused-array beamforming based on impulse waveforms achieves efficient focusing of the radiation energy in the radiation-near-field region and beyond, and yields improvement in focusing performance and angular resolution for increased values of array spatial bandwidth. Such practical advantages are achieved without encountering grating lobes, large sidelobe level, or distortion of the radiation beam pattern that often limit the performance of the conventional narrowband phased array antennas. View full abstract»

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  • The Application of a Modified Differential Evolution Strategy to Some Array Pattern Synthesis Problems

    Publication Year: 2008 , Page(s): 1919 - 1927
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (518 KB) |  | HTML iconHTML  

    A high convergence rate and a robust exploration ability constitute a contradiction in modern heuristic optimization techniques. This paper describes a modified differential evolution strategy (MDES) that builds up a balanced relationship between the two contradictive elements by introducing several modifications into the conventional differential evolution strategy (DES). The novel MDES opens up an effective and robust approach for global optimization problems. Several representative mathematical functions are minimized using various optimization methods and the convergence rates are compared to evaluate the performance of MDES. Moreover, array synthesis examples which can be formulated as non-convex problems are presented, including the optimal synthesis of sum and difference patterns and the synthesis of unequally spaced arrays. Numerical results demonstrate that the proposed approach improves the performance of the algorithm significantly, in terms of both the convergence rate and the exploration ability. View full abstract»

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  • Time Domain Synthesis of Pulsed Arrays

    Publication Year: 2008 , Page(s): 1928 - 1938
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1433 KB) |  | HTML iconHTML  

    Pulsed arrays are becoming popular in new ultra-wideband applications to enhance the robustness of transmitted and received signals in complex environments and to identify the angle of arrival of multiple echoes. A global synthesis technique is here proposed to shape the array field in accordance to given angle-time constraints. The synthesis problem is cast as the inverse Radon transform of a desired array mask, applying the alternate projections method to include constraints over the input signals' waveform and to improve the synthesis robustness. The unknown array currents are generated as linear combinations of Hermite-Rodriguez functions in order to achieve a simple and realizable beamforming network. The effectiveness of the method is demonstrated by many examples. View full abstract»

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  • Memory Enhanced PSO-Based Optimization Approach for Smart Antennas Control in Complex Interference Scenarios

    Publication Year: 2008 , Page(s): 1939 - 1947
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1003 KB) |  | HTML iconHTML  

    In the framework of control methods for adaptive phased-arrays, this paper deals with complex communication scenarios by considering a memory-enhanced cooperative algorithm. Compared to existing approaches where far-field interferences are taken into account, the proposed analysis considers a more realistic situation where the jamming sources are located either in the near-field or in the far-field of the receiving antenna. In order to carefully address the arising challenges and to effectively deal with such complex environments, an optimization approach based on an enhanced particle swarm optimizer (PSO)-based algorithm is used. The obtained results seem to confirm the effectiveness of the proposed technique in terms of both signal-to-noise ratio and computational costs and complexity. View full abstract»

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  • Pulse Propagation Along Transmission Lines in the Presence of Corona and Their Implication to Lightning Return Strokes

    Publication Year: 2008 , Page(s): 1948 - 1959
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (370 KB) |  | HTML iconHTML  

    Transmission line equations in air in the presence of corona are derived. The analysis shows that the corona caused by a voltage or a current pulse propagating along a transmission line can be represented by a series of corona current sources distributed along the line. Corona has two effects on the voltage or current pulses propagating along a transmission line. First, it will clamp down the pulse amplitude at the front of the pulse to the corona threshold. Second, it will cause the portion of the pulse whose amplitude is larger than the corona threshold to travel with a speed less than the speed of light. The effects of corona on the voltage or current pulses propagating along a transmission line can also be evaluated by introducing a time varying capacitance and a conductance into the transmission line. If the time varying capacitance is assumed to be proportional to the ratio between the corona charge and the applied voltage then one requires both this and the time varying conductance to represent the corona effects more accurately. Analysis of the return stroke as a current pulse propagating along a transmission line undergoing corona shows that the corona effects may explain the reason why the measured return stroke speeds are considerably less than the speed of light. Moreover, based on the effects of corona, a physical justification for the concepts used in the current generation type return stroke models is provided. View full abstract»

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  • On the Accuracy of Several Approximate Theories Used in Quantifying the Propagation Effects on Lightning Generated Electromagnetic Fields

    Publication Year: 2008 , Page(s): 1960 - 1967
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB) |  | HTML iconHTML  

    The effect of finitely conducting ground on the signature of lightning generated vertical electric fields at ground level was evaluated by numerical solution of Sommerfeld's integrals. Results are presented for distances between 10 m to 1 km from the lightning channel and for ground conductivities in the range of 0.01 and 0.001 S/m. The results obtained from the exact theory are compared with the predictions of several approximate theories available in the literature. Based on that comparison the limits of validity of these approximate theories are obtained. View full abstract»

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  • Potential Effects of the Ionosphere on Space-Based SAR Imaging

    Publication Year: 2008 , Page(s): 1968 - 1975
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1215 KB) |  | HTML iconHTML  

    There has been a considerable interest in the use of lower frequency (VHF/UHF) space-based synthetic aperture radar (SAR) for realizing the foliage and ground penetration. The phase perturbation, signal distortion and imaging resolution degradation by the ionosphere will be particularly severe, however the model is not yet well established and still needs to be further studied. In this paper, on the basis of possible improvements for the model proposed by Ishimaru and others, potential ionospheric effects on SAR imaging are evaluated. First, for analyzing azimuthal resolution, we apply the fourth moment recently obtained in general case of strong fluctuation regimes, which is expected to give results for wider conditions. The Gaussian approximation was used in the previous model; however it is only valid in the fully saturated regimes. Second, for analyzing image shift and distortion, besides group delay, the higher-order dispersion is considered. Third, for discussing range resolution degraded due to pulse broadening, besides the dispersion, the multiple scattering of ionospheric turbulence is studied. Fourth, the Faraday rotation effect is analyzed. Numerical simulations are shown using ionospheric turbulence spectrum and TEC inferred from the International Reference Ionosphere (IRI) and satellite beacon observations. View full abstract»

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  • Electromagnetic Excitation of PEC Slotted Cones by Elementary Radial Dipoles—A Semi-Inversion Analysis

    Publication Year: 2008 , Page(s): 1976 - 1983
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (798 KB) |  | HTML iconHTML  

    A novel method is presented that is based on the use of the Kontorovich-Lebedev integral transform and the semi-inversion technique, developed for building the efficient and accurate numerical solutions to the boundary-value problems of electromagnetic wave scattering by the 3D coaxial slotted cones. A generic structure under consideration consists of two semi-infinite coaxial circular perfectly electrical conducting and zero-thickness cones with periodic longitudinal slots excited by a radial dipole. The considered problem is reduced to an infinite set of linear algebraic equations of the Fredholm second kind that is truncated and solved numerically. A detail analysis of the accuracy and convergence of the method is presented. The basic electromagnetic characteristics such as the field behavior near the structure singularities, field patterns in the wave zone, and field polarization for various problem parameters are investigated for the cones excited by on-axis elementary dipoles. The slotted cones allow obtaining more directional patterns in wider band than the solid ones. View full abstract»

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  • Degeneration of Electromagnetic Creeping Waves in a Vicinity of Critical Values of Anisotropic Impedance

    Publication Year: 2008 , Page(s): 1984 - 1992
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (447 KB) |  | HTML iconHTML  

    Electromagnetic creeping waves on a 3-dimensional surface with an anisotropic impedance boundary condition are considered. The influence of the impedance is examined. The standard asymptotic formula for the creeping waves contains the factor 1/(tau-q2) where tau is the attenuation parameter and q is the Fock parameter which depends on the impedance matrix. Analysis of the equation for the attenuation parameter which describes its dependence on q shows that there exist such critical values of q when the factor 1/(tau-q2) diverges and the usual asymptotic formula gives infinite result. The equation for the critical values of the parameter q is derived and the 4 first critical values are found numerically. The new local asymptotics valid in domain of the size k-2/9 (where k is the wave number) is derived in the supposition that the divergence takes place on a curve crossed by creeping waves. This new asymptotic decomposition is carried out by powers of the small parameter k-1/9. The effect of creeping wave passing through the line where the usual asymptotics diverges is examined. View full abstract»

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  • Two-Term Ritz–Galerkin Solution for the Low Frequency Scattering by a Rectangular Trough in a Soft Ground Plane

    Publication Year: 2008 , Page(s): 1993 - 2001
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (474 KB) |  | HTML iconHTML  

    An analytic form is derived for the diffracted field that originates when a transverse-magnetic plane-wave excites a rectangular trough cut in a ground plane. The low-frequency analysis is valid for trough apertures that are less than half a free-space wavelength in width. Trough depth is arbitrary. The quasi-static nature of the long wave problem is exploited by approximating the aperture field as a complex superposition of decoupled symmetric and antisymmetric solutions to Laplace's equation in the vicinity of the aperture, subject to Dirichlet boundary conditions. Geometrical contributions to the final algebraic expressions for the two aperture coefficients arise from two sources: A rapidly convergent series governs the aperture interaction with the trough modes and the effect of the half-space is embodied in a small number of terms of low powers in kappaalpha and factors of In kappaalpha. View full abstract»

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  • New Full Wave Theory for Plane Wave Scattering From Rough Dielectric Surfaces—The Correction Current Method: TE Polarization

    Publication Year: 2008 , Page(s): 2002 - 2017
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1731 KB) |  | HTML iconHTML  

    A new full-wave theory for scattering from rough dielectric surfaces-called the correction current (CC) method-is presented. An iterative solution is developed leading to a first-order scatter pattern in the form of a single integral, making it computationally efficient and capable of showing surface parameter dependencies explicitly. The first-order CC-scatter solution is shown to satisfy reciprocity, to comply with a pattern symmetry relation, and to be accurate over a wide range of surface parameters. The theory is also shown to be capable of quantifying its field errors resulting in an error criterion that is derived from the theory itself (which is not generally available in other theories). Radar cross sections for random rough surfaces with Gaussian statistics are compared to data generated by solving the electric field integral equation using the method of moments. Good agreement was shown to result for a wide range of surface parameters. View full abstract»

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  • A Controllable Magnetic Metamaterial: Split-Ring Resonator With Rotated Inner Ring

    Publication Year: 2008 , Page(s): 2018 - 2022
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB) |  | HTML iconHTML  

    The split-ring resonator (SRR) with a rotated inner ring is analyzed to assess the controllability of its magnetic resonant frequency. Numerical simulations were carried out to verify the proposed theory and the controllability. The results show that by rotating the inner ring, magnetic resonant frequency of SRR increases as the angle between the two splits decreases. Simulation results and theoretical predictions are consistent with each other, which indicates that the proposed theory is quite effective in analyzing the controllability. Implementation of the controllability of SRRs with rotated inner ring was realized by using control bars. The effects brought by the materials and radii of control bars were investigated, which shows that the use of control bars increases the magnetic frequency slightly and that materials and radii of control bars have little effect on the magnetic resonant frequency. The theory and implementation method of the controllability proposed in this paper is of great practical values in designing controllable magnetic metamaterials. View full abstract»

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  • Incorporation of Conductor Loss in the Unconditionally Stable ADI-FDTD Method

    Publication Year: 2008 , Page(s): 2023 - 2030
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (483 KB) |  | HTML iconHTML  

    A surface-impedance boundary condition (SIBC) is presented for an unconditionally stable alternating-direction implicit (ADI) finite-difference time-domain (FDTD) method. The conformal SIBC formulation based on locally conformal grids is capable of modeling the conductor loss of arbitrarily-shaped lossy metal structures. The work is described in the framework of the finite-integration technique (FIT) formulation of the ADI-FDTD. The paper focuses on the proposed ADI-FDTD SIBC formulation and its extensive validation. For this purpose, cylindrical and spherical cavity resonators are used for numerical tests. The quality factor Q is directly proportional to wall loss and is particularly sensitive to the accuracy of loss calculation. The resonator structure consists only of a vacuum-filled metal cavity and is thus free of additional sources of error that are caused by other extensions to the basic ADI-FDTD algorithm. The formulation is validated by comparison with analytic results and numerical data calculated using CST Microwave Studio (MWS). The convergence rate of the results is of second order, i.e., the error reduces to one quarter as the mesh resolution is doubled. View full abstract»

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  • A Flexible and Efficient Higher Order FE-BI-MLFMA for Scattering by a Large Body With Deep Cavities

    Publication Year: 2008 , Page(s): 2031 - 2042
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1213 KB) |  | HTML iconHTML  

    The hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) is applied to solve the challenge problem of scattering by a large body with deep cavities in this paper. The hierarchical higher order curvilinear vector finite element (HCVFE) is employed to reduce the numerical dispersion error in the FEM and to efficiently model the geometry of the cavity. The coupling approaches are investigated at the interface between the FE region and the BI region for handling the problem of the different order basis functions and meshes used in the FE and BI region. The problems encountered with the previous decomposition algorithm of FE-BI-MLFMA are pointed out and analyzed in this paper. A special algorithm of FE-BI-MLFMA is designed based on the distinct geometry characteristics of deep cavity. Numerical results are presented to demonstrate the accuracy, efficiency and flexibility of the higher order FE-BI-MLFMA for scattering by a large body with big and deep cavities. View full abstract»

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

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Editor-in-Chief                                                 Kwok W. Leung