Showing papers in "Progress in Electromagnetics Research-pier in 2006"
TL;DR: In this article, the authors compared the performance of two cases of central element feeding and showed that the reduction in the sidelobe level to more than 20 dB was achieved without extra signal processing especially for small-sized arrays that have smaller number of elements and rings.
Abstract: Concentric circular antenna array (CCAA) has interesting features over other array configurations.A uniform arrangement of elements is assumed where the interelement spacing is kept almost half of the wavelength and the array parameters such as the steering matrix and gain are determined.The array performance such as beam power pattern, sidelobe level and beamwidth are discussed in two cases of central element feeding.The two cases are compared showing the reduction in the sidelobe level to more than 20 dB in the case of central element feeding without extra signal processing especially for small- sized arrays that have smaller number of elements and rings.
207 citations
TL;DR: An efficient method for the pattern synthesis of the linear antenna arrays with the prescribed null and multi-lobe Beamforming is presented and several illustrative examples of uniform excited array patterns with the main beam placed in the direction of the useful signal.
Abstract: In this article, an efficient method for the pattern synthesis of the linear antenna arrays with the prescribed null and multi-lobe Beamforming is presented. Multi-lobe pattern and adaptive nulling of the pattern is achieved by controlling only the phase of each array element. The proposed method is based on the Sequential Quadratic Programming (SQP) algorithm and the linear antenna array synthesis was modelled as a multi-objective optimization problem. Multi-objective optimization is concerned with the maximization (or minimization) of a vector of objectives functions in the directions of desired signal that can be subject of a number of constraints (in our case, the constraints can be imposed as the null in the direction of interfering signal). To verify the validity of the technique, several illustrative examples of uniform excited array patterns with the main beam is placed in the direction of the useful signal and null is placed in the direction of potential interferers, and multi-beam patterns are demonstrated.
188 citations
TL;DR: In this paper, the authors measured what influence the sinusoidal transmission characteristics of the electric power line with various forms gave to the transmission characteristic of OFDM (Orthogonal Frequency Division Multiplexing) signal through PLC (power line communication system) modem.
Abstract: In this paper, we measured what influence the sinusoidal transmission characteristics of the electric power line with various forms gave to the transmission characteristic of OFDM (Orthogonal Frequency Division Multiplexing) signal through PLC (power line communication system) modem. The electric power line transmission line with various forms in a real environment is classified into two basic elements, which are an outlet type branch and a switch type branch. Next, PHY rate (Physical rate) is measured for each basic element connected with the PLC modem. At this time, the transmission characteristics of the electric power line are simulated from measured data. OFDM sending and receiving systems are composed on the computer, and the PHY rate is simulated. By comparing with measured and calculated values, it is revealed that PHY rate of PLC modem is most affected in the case of the power line transmission characteristics having broad band and high level attenuation and is not affected in the case of that having narrow band group delay variation.
151 citations
TL;DR: In this paper, a planar microstrip-fed tab monopole antenna for ultra wideband wireless communications applications is presented, which has a small size of 16 × 19 mm and provides an ultra wide bandwidth from 2.8 to 28 GHz with low VSWR level and good radiation characteristics.
Abstract: This paper presents a planar microstrip-fed tab monopole antenna for ultra wideband wireless communications applications. The impedance bandwidth of the antenna is improved by adding slit in one side of the monopole,introducing a tapered transition between the monopole and the feed line,and adding two-step staircase notch in the ground plane. Numerical analysis for the antenna dimensional parameters using Ansoft HFSS is performed and presented. The proposed antenna has a small size of 16 × 19 mm,and provides an ultra wide bandwidth from 2.8 to 28 GHz with low VSWR level and good radiation characteristics to satisfy the requirements of the current and future wireless communications systems.
150 citations
TL;DR: In this article, a broadband, low profile dielectric resonator antenna with a stepped microstrip feed is presented. But the antenna size is not reduced by using metallic strips or patches.
Abstract: This paper presents a novel broadband, low-profile dielectric resonator antenna using relatively low dielectric constant substrate material. The rectangular DRA is fed with a stepped microstrip feed to ensure efficient coupling. Bandwidths in excess of 17% are obtained. In addition, the paper investigates methods to miniaturize the antenna using metallic strips or patches. Substantial size reduction is demonstrated while maintaining a reasonable bandwidth. Simulations as well as experimental results are presented.
145 citations
TL;DR: In this paper, the authors introduced a first order accurate resonance model based on a second order Pade approximation of the reflection coefficient of a narrowband antenna, which is characterized by its Q factor.
Abstract: In this paper, we introduce a first order accurate resonance model based on a second order Pade approximation of the reflection coefficient of a narrowband antenna. The resonance model is characterized by its Q factor, given by the frequency derivative of the reflection coefficient. The Bode-Fano matching theory is used to determine the bandwidth of the resonance model and it is shown that it also determines the bandwidth of the antenna for sufficiently narrow bandwidths. The bandwidth is expressed in the Q factor of the resonance model and the threshold limit on the reflection coefficient. Spherical vector modes are used to illustrate the results. Finally, we demonstrate the fundamental difficulty of finding a simple relation between the Q of the resonance model, and the classical Q defined as the quotient between the stored and radiated energies, even though there is usually a close resemblance between these entities for many real antennas.
138 citations
TL;DR: In this article, a wideband bowtie antenna having 2:1 VSWR bandwidth of 46% is designed for the transmission and reception of microwave signals at the frequency of 3000 MHz.
Abstract: Active microwave imaging is explored as an imaging modality for early detection of breast cancer. When exposed to microwaves, breast tumor exhibits electrical properties that are significantly different from that of healthy breast tissues. The two approaches of active microwave imaging — confocal microwave technique with measured reflected signals and microwave tomographic imaging with measured scattered signals are addressed here. Normal and malignant breast tissue samples of same person are subjected to study within 30 minutes of mastectomy. Corn syrup is used as coupling medium, as its dielectric parameters show good match with that of the normal breast tissue samples. As bandwidth of the transmitter is an important aspect in the time domain confocal microwave imaging approach, wideband bowtie antenna having 2:1 VSWR bandwidth of 46% is designed for the transmission and reception of microwave signals. Same antenna is used for microwave tomographic imaging too at the frequency of 3000 MHz. Experimentally obtained time domain results are substantiated by finite difference time domain (FDTD) analysis. 2-D tomographic images are reconstructed with the collected scattered data using distorted Born iterative method. Variations of dielectric permittivity in breast samples are distinguishable from the obtained permittivity profiles.
135 citations
TL;DR: In this article, a modified microstrip-fed dipole antenna with simplified balun was proposed to improve the usable bandwidth by increasing the stability of the radiation patterns, which achieved a wide usable bandwidth of more than 84% with high radiation pattern stability.
Abstract: In this paper,the regular microstrip-fed dipole antenna with simplified balun is modified to improve the usable bandwidth by increasing the stability of the radiation patterns. The presented antenna consists of two parallel dipoles of different lengths to obtain two main resonances. The distance between the two dipoles is adjusted to reduce the return loss between the two main resonances. A wide usable bandwidth of more than 84% is obtained with high radiation pattern stability. The proposed antenna is simple and small in size. The results of a modified two-element array configuration from this antenna show that it is very good candidate for wideband phased array applications.
133 citations
TL;DR: In this article, the authors present electromagnetic energy absorption in the homogeneous and layered human body models due to body-worn UWB antennas, at frequencies of 3, 6 and 8 GHz.
Abstract: This paper presents electromagnetic energy absorption in the homogeneous and layered human body models due to body-worn UWB antennas, at frequencies of 3, 6 and 8 GHz. Typical small planar UWB antennas are used in this study: printed UWB disc monopole and UWB slot antenna. Distances of 2, 5 and 10 mm (reactive near-field region) between antennas and human body were chosen, approximating realistic scenarios of operation in Wireless Body Area Networks. To approximate different parts of the human body, or body variations among different users, we compare results obtained for the planar homogeneous (muscle) model with those for three-layer body models (skin, fat and muscle), with different thicknesses of the skin (0.5- 2 mm) and fat (1-9 mm) tissue. For these body models we investigate the electromagnetic energy absorption mechanism by examining the peak 1-g SAR and peak SAR (without mass averaging). Based on our results we present and discuss new finding concerning the general electromagnetic energy absorption mechanism in human tissues under reactive near-fields exposure conditions.
129 citations
TL;DR: In this paper, the design of a compact, single feed, dual frequency dual polarized and electronically reconfigurable microstrip antenna is presented, where a square patch loaded with a hexagonal slot having extended slot arms constitutes the fundamental structure of the antenna.
Abstract: The design of a compact, single feed, dual frequency dual polarized and electronically reconfigurable microstrip antenna is presented in this paper. A square patch loaded with a hexagonal slot having extended slot arms constitutes the fundamental structure of the antenna. The tuning of the two resonant frequencies is realized by varying the effective electrical length of the slot arms by embedding varactor diodes across the slots. A high tuning range of 34.43% (1.037–1.394 GHz) and 9.27% (1.359–1.485 GHz) is achieved for the two operating frequencies respectively, when the bias voltage is varied from 0 to −30 V. The salient feature of this design is that it uses no matching networks even though the resonant frequencies are tuned in a wide range with good matching below −10 dB. The antenna has an added advantage of size reduction up to 80.11% and 65.69% for the two operating frequencies compared to conventional rectangular patches.
124 citations
TL;DR: In this article, a rectangular slot excited by microstripline feed with a U-shaped tuning stub was used to improve the matching performance of wideband printed rectangular slotantennas.
Abstract: MICROSTRIPLINEANDCPWFEDULTRAWIDEBANDSLOTANTENNASWITHU-SHAPEDTUNINGSTUBANDREFLECTORR.Chair,A.A.Kishk,K.F.Lee,C.E.Smith,andD.KajfezDepartmentofElectricalEngineeringCenterforAppliedElectromagneticSystemsResearch(CAESR)UniversityofMississippiUniversity,MS38677,USA—Widebandprintedrectangularslotantennasbackedwithreflectorsforunidirectionalradiationpatternsareinvestigated. AU-shaped tuning stub is used to improve the matching. Two differentfeeding mechanisms are introduced. A rectangular slot excited bymicrostriplinefeedwithaU-shapedtuningstubgivesanimpedancebandwidth of 110% (
TL;DR: In this article, different sources of frequency-dependent metal conductivity at optical frequen- cies are taken into account, such as the skin effect, dimensional (length-size) resonance of metal particles, and the Drude model.
Abstract: Mathematical modeling of composites made of a dielectric base and randomly oriented metal inclusions is considered. Different sources of frequency-dependent metal conductivity at optical frequen- cies are taken into account. These include the skin-effect, dimensional (length-size) resonance of metal particles, and the Drude model. Also, the mean free path of electrons in metals can be smaller than the char- acteristic sizes of nanoparticles, and this leads to the decrease in con- ductivity of the metal inclusions. These effects are incorporated in the Maxwell Garnett mixing formulation, and give degrees of freedom for forming desirable optical frequency characteristics of composite media containing conducting particles.
TL;DR: Theoretical results on the effect of antenna mutual coupling (MC) on capacity of multiple-input multiple-output (MIMO) wireless channels are presented with particular emphasis on the case of high signal to noise ratio (SNR) scenario.
Abstract: Theoretical results on the effect of antenna mutual coupling (MC) on capacity of multiple-input multiple-output (MIMO) wireless channels are presented in this paper with particular emphasis on the case of high signal to noise ratio (SNR) scenario. Two cases are considered, 1- channel capacity variations due to MC effect on correlation properties and target average receive SNR and 2- channel capacity variations due to MC effect on correlation properties at fixed average receive SNR. It is shown that the effect of MC on MIMO channel capacity can be positive or negative depending on the propagation environment spatial correlation properties and the characteristics of the transmitter and receiver MC matrices. Conditions where MC has positive and negative effects on MIMO channel capacity in the two considered cases are identified. Numerical results for half wavelength dipole antenna supporting the theoretical observations are presented.
TL;DR: In this paper, the characteristics of four types of artificial magnetic conductor (AMC) surface, including a mushroom-like (electromagnetic band gap) EBG, uniplanar compact EBG (UC-EBG), Peano curve, and Hilbert curve, as a ground plane for a low-profile antenna were investigated.
Abstract: —This paper investigated comparatively the characteristics of four types of artificial magnetic conductor (AMC) surface, including a mushroom-like (electromagnetic band gap) EBG, uniplanar compact EBG (UC-EBG), Peano curve, and Hilbert curve, as a ground plane for a low-profile antenna. The AMC surface structures are designed to have an in-phase reflection property for a plane wave of normal incidence in the vicinity of 2.45 GHz. The bandwidths of the in-phase reflection for the AMC surfaces and return losses, radiation patterns, and gains of the horizontal wire antennas on the AMC ground planes are all measured and compared with each other. The measured data show that all the AMC surfaces act as good ground planes for a lowprofile antenna, yet the bandwidth and gain of the mushroom-like EBG structure are broader and larger, respectively, than those of the other structures.
TL;DR: In this paper, the analysis of a two-segment rectangular dielectric resonator antenna (DRA) for broadening of the impedance bandwidth was discussed, and an appropriate structure was obtained that illustrates more than 76.8% impedance bandwidth (for S11>10 dB) at 3.32-7.46 GHz frequency band.
Abstract: This paper discusses the analysis of a novel two-segment rectangular dielectric resonator antenna (DRA) for broadening of the impedance bandwidth. In the proposed configuration, two rectangular dielectric sections are used which are separated by a metal plate. With this configuration, it is possible to excite two adjacent resonant frequencies. Utilizing the two-segment thin DRA and skillfully varying its aspect ratio, an appropriate structure is obtained that illustrates more than 76.8% impedance bandwidth (for S11>10 dB) at 3.32- 7.46 GHz frequency band.
TL;DR: In this article, the theoretical foundations of near-field-farfield transformations with spiral scannings are revisited and a unified theory is provided by introducing a sampling representation of the radiated electromagnetic field on a rotational surface from the knowledge of a nonredundant number of its samples on a spiral wrapping the surface.
Abstract: In this paper, the theoretical foundations of near-field-farfield transformations with spiral scannings are revisited and a unified theory is provided. This is accomplished by introducing a sampling representation of the radiated electromagnetic field on a rotational surface from the knowledge of a nonredundant number of its samples on a spiral wrapping the surface. The obtained results are general, since they are valid for spirals wrapping on quite arbitrary rotational surfaces, and can be directly applied to the pattern reconstruction via near-field-far-field transformation techniques. Numerical tests are reported for demonstrating the accuracy of the approach and its stability with respect to random errors affecting the data.
TL;DR: In this paper, the authors present a characterization of the open-ended coaxial probe which is used to measure the normal component of the electric field, and use a 3D positioning system of the probe to make accurate measurements.
Abstract: A completely automatically near-field mapping system is developed within IRSEEM (Research Institute for Electronic Embedded Systems) in order to determine electromagnetic field radiated by electronic systems. This test bench uses a 3D positioning system of the probe to make accurate measurements. The main element of this measurement tool is the probe. This paper presents a characterization of the open-ended coaxial probe which is used to measure the normal component of the electric field.
TL;DR: In this article, the singularity subtraction method for planar surface elements with RWG, n×RWG, rooftop, and n×rooftop basis functions is presented, and the hybrid use of these functions is discussed.
Abstract: Numerical solution of electromagnetic scattering problems by the surface integral methods leads to numerical integration of singular integrals in the Method of Moments. The heavy numerical cost of a straightforward numerical treatment of these integrals can be avoided by a more efficient and accurate approach based on the singularity subtraction method. In the literature the information of the closed form integral formulae required by the singularity subtraction method is quite fragmented. In this paper we give a uniform presentation of the singularity subtraction method for planar surface elements with RWG, ˆ n×RWG, rooftop, and ˆ n×rooftop basis functions, the latter three cases being novel applications. We also discuss the hybrid use of these functions. The singularity subtraction formulas are derived recursively and can be used to subtract more than one term in the Taylor series of the Green's function.
TL;DR: Three types of novel bowtie antennas with round corners are presented, including quadrate, rounded-edge and triangular shapes, which have better return loss, flatter input impedance, more stable radiation patterns and smaller area at the same time.
Abstract: In this paper, three types of novel bowtie antennas with round corners are presented and studied carefully, including quadrate, rounded-edge and triangular shapes, which have better return loss, flatter input impedance, more stable radiation patterns and smaller area at the same time. The effect of round corners is attached importance to due to their novelty. The conclusion is drawn that adding the round corners at the sharp vertexes of radiation surfaces can have positive effects on performances of not only bowtie antennas but also the others.
TL;DR: In this article, a semi-empirical approach and an analytical model were proposed to predict the total path loss in various indoor communication links, taking into account the newanalytical methods of the derivation of the fading phenomenon between floors and along corridors, respectively.
Abstract: In this work, we present a semi empirical approach and the analytical model on howto predict the total path loss in various indoor communication links, taking into account the newanalytical methods of the derivation of the fading phenomenon between floors and along corridors, respectively. We take into account the stochastic method of slowand fast fading estimations, caused by diffraction and multipath phenomena, respectively. The statistical parameters required for statistical description of the diffraction and multipath phenomena, such as the standard deviations of the signal strength due to slow and fast fading are obtained from the corresponding measurements. The path loss characteristics together with evaluated parameters of slowand fast fading give a more precise link budget predictor, and obtain full radio coverage of all subscribers located in the area of service inside each building. Based on strict and completed path loss prediction, an algorithm of link budget performance is presented for different scenarios of radio propagation within indoor communication links. Results of proposed unified approach are compared with the analytical Bertoni's model, which is well-known and usually used in link budget design in various indoor environments. The results are also compared with measurements carried out for different propagation scenarios, along corridor and between floors, occurred in the indoor communication channels. A better agreement with experimental data is obtained compared to the model in consideration.
TL;DR: In this article, the authors investigated broadband planar antennas that consist of a wide rectangular slot with various tuning stubs, and the antennas are fed by coplanar waveguides.
Abstract: This paper investigates broadband planar antennas that consist of a wide rectangular slot with various tuning stubs. The antennas are fed by coplanar waveguides. Wide slots containing a single tuning stub, V-shaped stubs, as well as inverted F-shaped stubs are investigated. Despite using a high dielectric constant substrate, the proposed antennas exhibit very broad bandwidth. They also have broadside bidirectional radiation. The radiation pattern stability with frequency for the various configurations is presented. One of the proposed configurations, the inverted F stub in a wide rectangular slot, produced very stable radiation patterns over its entire impedance bandwidth of about 40%. Also, an impedance bandwidth of 44% was obtained for the V-shaped stub in a rectangular slot. Simulations as well as experimental results are presented.
TL;DR: In this article, an edge coupled microstrip coupler with defected ground structure is presented, where a normally 7 dB coupler designed on Alumina substrate is converted into a 3dB coupler by cutting single rectangular slot in the ground plane encompassing the two transmission lines.
Abstract: In this paper an edge coupled microstrip coupler with defected ground structure is presented. A normally 7 dB coupler designed on Alumina substrate is converted into a 3 dB coupler by cutting single rectangular slot in the ground plane encompassing the two transmission lines. Other properties of backward wave coupler remain the same, except for a tighter coupling. With this method of design optimization, it will be possible to fabricate a 3 dB coupler in compact form without strain in fabrication process. The structure is analyzed considering magnetic and electric coupling between the two transmission lines. Simulation based studies show reasonable agreement between analytical results and corresponding simulation results.
TL;DR: In this paper, a new method to improve the gain of a circular waveguide array antenna with metamaterial structure is presented, which can realize congregating the radiation energy, so the antenna increases while the side lobe level decreases.
Abstract: Abstract—A new method to improve the gain of circular waveguide array antenna with metamaterial structure is presented. The electromagnetic characteristics of metamaterial and circular waveguide antenna with metamaterial structure are studied by using numerical simulation method, which are also compared with those of the conventional circular waveguide antenna. The simulation and experimental results show that this method is effective and metamaterial structure can realize congregating the radiation energy, so the gain of the antenna increases while the side lobe level decreases.
TL;DR: In this paper, the authors proposed a Pocklington integro-differential equation for simple grounding systems, where the influence of a dissipative half-space is taken into account via the reflection coefficient appearing within the integral equation kernel.
Abstract: The paper deals with the transient impedance calculation for simple grounding systems. The mathematical modelmodel is based on the thin wire antenna theory. The formulation of the problem is posed in the frequency domain, while the corresponding transient response of the grounding system is obtained by means of the inverse Fourier transform. The current distribution induced along the grounding system due to an injected current is governed by the corresponding frequency domain Pocklington integro-differential equation. The influence of a dissipative half-space is taken into account via the reflection coefficient (RC) appearing within the integral equation kernel. The principal advantage of the RC approach versus rigorous Sommerfeld integral approach is simplicity of the formulation and significantly less computational cost. The Pocklington integral equation is solved by the Galerkin Bubnov indirect boundary element procedure thus providing the current distribution flowing along the grounding system. The outline of the Galerkin Bubnov indirect boundary element method is presented in Part II of this work. Expressing the electric field in terms of the current distribution along the electrodes the feed point voltage is obtained by integrating the normal field component from infinity to the electrode surface. The frequency dependent input impedance is then obtained as a ratio of feed-point voltage and the value of the injected lightning current. The frequency response of the grounding electrode is obtained multiplying the input impedance spectrum with Fourier transform of the injected current waveform. Finally, the transient impedance of the grounding system is calculated by means of the inverse Fourier transform. The vertical and horizontal grounding electrodes, as simple grounding systems, are analyzed in this work. The Part I of this work is related to the vertical
TL;DR: In this article, the effect of EBG superstrates on the return loss of PFMA has been examined and the EBG was used as a resonance load to the primary radiation source (PFMA) and then by choosing the appropriate geometrical parameters of the structure we can obtain suitable impedance matching.
Abstract: In this paper, the effect of Electromagnetic Bandgap (EBG) Superstrates on return loss of the Probe-Fed Microstrip Antenna (PFMA) has been examined. Originally the EBG superstrate layer made by Frequency Selective Surface (FSS) layers is used to increase the directivity of the PFMA, but to increase the efficiency of the whole structure including the PFMA and EBG superstrate it is necessary to have suitable impedance matching. In this paper the EBG superstrate as a resonance load to the primary radiation source (PFMA) and then by choosing the appropriate geometrical parameters of the structure we can obtain suitable impedance matching beside the directivity enhancement of the primary radiation source.
TL;DR: In this paper, a waveguide filled by several dielectric layers was proposed for microwave filters and the relative electric permittivity and the length of the layers were optimally obtained using a least mean square method.
Abstract: In this paper, a new structure is proposed for microwave filters. This structure utilizes a waveguide filled by several dielectric layers. The relative electric permittivity and the length of the layers are optimally obtained using a least mean square method. The usefulness of the proposed structure is verified using an example.
TL;DR: In this article, the authors performed permittivity and conductivity studies of corn syrup in various concentrations using coaxial cavity perturbation technique over a frequency range of 250 MHz-3000 MHz.
Abstract: Permittivity and conductivity studies of corn syrup in various concentrations are performed using coaxial cavity perturbation technique over a frequency range of 250 MHz-3000 MHz. The results are utilized to estimate relaxation time and dipole moments of the samples. The stability of the material over the variations of time is studied. The measured specific absorption rate of the material complies with the microwave power absorption rate of biological tissues. This suggests the feasibility of using corn syrup as a suitable, cost effective coupling medium for microwave breast imaging. The material can also be used as an efficient breast phantom in microwave breast imaging studies.
TL;DR: In this paper, the effect of different antenna array geometries on MIMO channel properties is investigated in urban city street grid propagation environment, namely, uniform linear array (ULA), uniform circular array (UCA), uniform rectangular array (URA), and uniform cubic array (UCuA), with the same number of antenna elements and fixed inter-element spacing.
Abstract: Propagation environment and antenna array configuration have significant effect on spatial correlation properties of multiple- input multiple-output (MIMO) wireless communications channels. In this paper the effect of different antenna array geometries on MIMO channel properties is investigated in urban city street grid propagation environment. Four antenna array geometries with the same number of antenna elements and fixed inter-element spacing are considered, namely, uniform linear array (ULA), uniform circular array (UCA), uniform rectangular array (URA) and uniform cubic array (UCuA). The effect of ULA orientation in azimuthal plane on MIMO channel ergodic capacity is also investigated. Varying orientation angle from 0 to π at the two communication ends is considered. The investigation is carried out based on three dimensional (3D) spatial multi-ray realistic propagation channel model covering different propagation types. It is shown that the antenna array geometry have significant impact on MIMO channel properties. Under different propagation scenarios the ULA shows superiority to the other considered geometries in terms of the ergodic channel capacity and number of spatial parallel channels. However, this superiority depends largely on the array azimuthal orientation.
TL;DR: In this article, the frequency-dispersive constitutive parameters of general bianisotropic media are reconstructed by an opti-mization approach, in which the constitutive parameter is optimized in order to match the measured reflection and transmission data for plane wave incidence onto biansotropic slabs.
Abstract: The reconstruction of the frequency-dispersive constitu- tive parameters of general bianisotropic media is achieved by an opti- mization approach. The constitutive parameters are optimized in order to match the measured reflection and transmission data for plane wave incidence onto bianisotropic slabs. Two optimization methods, in our case the differential evolution (DE) algorithm and the Nelder-Mead simplex method, are used for the reconstruction at low frequencies. The Nelder-Mead simplex method is then used to obtain the solutions at higher frequencies, where the initial guess is obtained by the linear extrapolation of the solutions at previous frequencies. The proposed reconstruction method is tested with both noiseless and noisy data, and is proven feasible and robust.