This paper presents method of moments based analysis of high-gain broad-band waveguide broad-wall longitudinal slot array antenna. Initially a basic two-element slot array antenna has been analyzed, and corresponding scattering parameter data have been obtained. The theoretical data have been compared with experimental data and Ansoft HFSS's simulated data to validate the proposed method. The excellent agreement obtained between the results validates the analysis. After validating the methodology attempts have been made to design a broad-band high-gain slot array antenna. An 18-element slot array antenna has been designed, fabricated and tested. The fabricated antenna provides a high gain over large band width.

Complementary split ring resonators (CSRRs) are applied on a UWB Vivaldi antenna to eliminate some unwanted narrow band services. Based on the sensitivity of band rejection, we successfully separate the whole radiating patch of a Vivaldi antenna into three subareas: The feeding area, where the Vivaldi antenna demonstrates a highly sensitive response to CSRRs with a narrow notching band; The transition-area, where CSRRs transfer a ultra wideband (UWB) Vivaldi into a narrow band antenna; and the rest area, where CSRRs are proved to have little effects on the antenna bandwidth property. A band notch Vivaldi antenna with 4.8 GHz to 5.4 GHz rejection band is demonstrated to verify our study from both simulated and measured results.

In a time domain Marching-on-in-degree (MOD) solver based on a Galerkin implementation of the Method of Moments (MoM), it is observed that the matrix elements for the matrix to be inverted contain integrals that are similar to the ones encountered in a frequency domain MoM solver using the piecewise triangular patch basis functions. It is also observed that the error in the evaluation of the matrix elements involving these integrals are larger in the time domain than those involved in the frequency domain MoM solvers. The objective of this paper is to explain this dichotomy and how to improve upon them when using the triangular patch basis functions for both the time and the frequency domain techniques. When the distance between the two triangular patches involved in the evaluation of the matrix elements, are close to each other or when the degree of the Laguerre polynomial in a MOD method is high, the integral accuracy will be compromised and the number of sampling points to evaluate the integrals need to be increased. Numerical results are presented to illustrate this point.

The frequency dependent characteristics of grounding system buried in half homogenous earth model have been discussed before; however, the importance of mutual inductive and capacitive effects on the grounding problems in both frequency and time domains is unclear. In order to study the importance of the mutual inductive, capacitative and conductive effects on the grounding problem in both frequency and time domains, hybrid method, which is a hybrid of Galerkin's method of moment and conventional nodal analysis method, has been used to study the dominant factor among the mutual inductive, capacitive and conductive effects in the paper.

In through-the-wall radar imaging (TWRI), wall returns are often stronger than target returns, which make the targets behind walls invisible in the radar image. Spatial filtering that relies on the removal of the spatial zero-frequency components is a useful way for wall-clutter mitigation. Unfortunately, it applies to through-the-wall radar (TWR) with synthetic aperture array only. In this paper, a method based on spatial signature is proposed to suppress the wall-clutter in multi-input and multi-output (MIMO) TWRI. Firstly, the traditional spatial filtering method is discussed, as well as the reasons for the inapplicability for MIMO TWR. Secondly, the wall and target spatial signatures based on MIMO array are analyzed, respectively. The results indicate that the former has stability and symmetry, whereas the latter not. Thirdly, according to the above differences, a new method, symmetry subtraction, is applied to describe the wall-clutter suppression procedure. Finally, simulation results demonstrate that the proposed method is efficient in mitigating the wall returns and highlighting the targets.

In this article, a novel coplanar waveguide (CPW)-fed miniaturization folded slot antenna for wireless local area network (WLAN) application is proposed and investigated. The multi-operating bands are achieved by folded slot antenna with slot loading. The parametric analysis of the antenna is done by the available electromagnetic solver HFSS11. The designed antenna has a small overall size of 28 mm×30 mm, and operates over the frequency ranges, 90 MHz (2.40 GHz-2.49 GHz), 400 MHz (3.4 GHz-3.8 GHz) and 870 MHz(5.17-6.04 GHz) suitable for WLAN 2.4/5.2/5.8 GHz and WiMAX 3.5/5.5 GHz applications. The proposed antenna is developed, and its measured characteristics are in good agreement with the simulated results. The experimental results show that the antenna gives dipole-like radiation patterns and good antenna gains over the operating bands. In addition, effects of main parameters of the triple-frequency for the design on the electromagnetic performance are examined and discussed in detail.

In this paper the derivation of a rigorous expression of the input admittance of a coaxially fed, infinite, lossy parallel plate waveguide (PPWG) is presented. The derivation makes use of the dyadic Green's function of the PPWG expressed as series a cylindrical wave-functions. Losses into the dielectric plates and on the conductors are considered rigorously. The approximation used in results presented in the past literature are critically discussed. Numerical experiments are performed to show the effects of the finite conductivity on the input impedance of the PPWG.

A finite element method based on the first order system LL* (FOSLL*) approach is derived for time harmonic Maxwell's equations in three dimensional domains. The finite element solution is a potential for the original field in a sense that the original field U is given by U = L*u. The Maxwellian boundary data appears as natural boundary condition. Homogeneous Dirichlet boundary conditions for the potential must be imposed, and they are circumvented with weak enforcement of boundary conditions and it is proved that the sesquilinear form of the finite element system is elliptic in the space where the Dirichlet boundary conditions are satisfied weakly.

We provide a sucient condition to select the parameters of Type 3 Non-Uniform Fast Fourier Transform (NUFFT) algorithms based on the Gaussian gridding to fulll a prescribed accuracy. This is a problem of signicant interest in many areas of applied electromagnetics, as for example fast antenna analysis and synthesis and fast calculation of the scattered elds, as well as in medical imaging comprising ultrasound tomography, computed axial tomography, positron emission tomogr aphy and magnetic resonance imaging. The approach is related to the one dimensional case and follows the work in A. Dutt and V. Rokhlin, SIAM J. Sci. Comp. 14 (1993). The accuracy of the proposed choice is rst numerically assessed and then compared to that achieved by the approach in J.-Y. Lee and L. Greengard, J. Comp. Phys. 206 (2005). The convenience of the strategy devised in this paper is shown. Finally, the use of the Type 3 NUFFT is highlighted for an electromagnetic application consisting of the implementation of the aggregation and disaggregation steps in the fast calculation of the scattered eld by the Fast Multipole Method.

This paper presents the technique to solve inhomogeneous profiles in the cross section of the helical rectangular waveguide. We present the technique to solve inhomogeneous dielectric profiles and the relation to the method of the propagation of electromagnetic fields along a helical waveguide with a rectangular cross section. The inhomogeneous examples will introduce for a dielectric slab, for a rectangular dielectric profile, and for a circular dielectric profile, in a rectangular metallic waveguide, in the cross section of the helical waveguide. This model is useful to improve the output results of the output power transmission in the cases of space helical waveguides, by increasing the step's angle or the radius of the cylinder. The application is useful for space helical waveguides in the microwave and the millimeter-wave regimes.

We study the electrodynamic characteristics of a strip loop antenna located on the surface of a circular column filled with a resonant magnetoplasma and surrounded by a homogeneous isotropic background medium. The antenna current is excited by a time-harmonic voltage creating an electric field with the azimuthal component in a narrow gap on the strip surface. It is shown that the current distribution and input impedance of such an antenna are strongly influenced by the presence of an infinite number of propagating quasielectrostatic modes that are guided by a column containing a resonant magnetoplasma.

A new method for the theoretical analysis of the third-order intermodulation distortion (IM3) in barium strontium titanate (BST) thin film interdigital capacitors (IDCs) on r-plane sapphire substrates is presented. Two circuit topologies-the dual and series dual BST varactor circuit-are proposed and their theoretical models along with simulated and measured results are presented. Low IM₃ is demonstrated and experimentally verified. By proper selective biasing, very low nulls are observed in both dual and series dual BST varactor circuit topologies which indicate minimum distortion. The measured first nulls are achieved at ±13 V and ± 20 V for the dual and series dual topologies respectively. These results demonstrate the potential of incorporating these highly linear BST varactors in silicon on sapphire (SoS) applications.

A high-gain and low-cost circularly polarized antenna array is proposed, which consists of four sequentially rotated circularly polarized square slot antennas (CPSSA). A novel feeding network is applied to the four-element array antenna, which results in increasing the axial ratio (AR) bandwidth. The measured impedance bandwidth for VSWR<2 is around 3.48 GHz (3.75 GHz~7.23 GHz) exhibiting a 2.8 GHz (3.8 GHz~6.6 GHz) 3 dB axial-ratio bandwidth (ARBW) and 9.05 dBic peak gain. The simulated and measured results are in good agreement with each other to verify the design.

A hybrid approach to find the optical response of periodic photonic structures to incident light is presented. The approach is based on a scattering matrix combination of the Finite Element Method (FEM) and the Fourier Modal Method (FMM). Optical response calculations include: scattering in both reflection and transmission directions, absorption and electric and magnetic field distributions inside the structure. The approach is tested on a structure --- composed of dielectric and metallic materials --- that is periodic in one direction. An analysis of the calculation accuracy shows that the approach depends on the subdivision into FEM and FMM domains and that the optimal subdivision depends on the calculations frequency range as well as on the structure geometry. For testing, we use the commercial FEM solver contained in CST Microwave Studio and a based on C/C++ Fourier Modal Method implementation.

This paper presents the performance analysis of Bistatic Interferometer BAsed on Spaceborne SAR (BIBASS). As a bistatic system with general configuration, the system response of BIBASS is azimuth/range dependent. Taking into account this peculiarity, the appropriate theoretical framework is developed to make a more accurate evaluation of the performance of BIBASS. Firstly, the interferometric features are studied. Then, considering all kinds of de-correlation factors, a comprehensive investigation of coherence of such a system is conducted, followed by the relative height accuracy analysis. The theoretical analysis and simulation show that BIBASS, with the ability of high-precision height measurement, can be widely applied as a novel remote sensing measurement system.

In this paper, design of broadband dual polarized electromagnetically coupled antenna array is proposed to achieve high isolation between two orthogonal ports. A dual polarized electromagnetically coupled microstrip antenna is designed with a suspended radiating element placed in inverted microstrip configuration and excited by two orthogonal microstrip line feeds to achieve broad bandwidth and high isolation. The antenna is designed for 5.8 GHz frequency band. In order to optimize the design, detailed parametric analysis of the antenna is presented. The antenna design is extended to 2×2 antenna array, with top layer radiating elements electromagnetically coupled to the open microstrip feed line network. The 6×6 antenna array is designed using 2×2 sub arrays with power divider network. The power divider network is integrated on the back side of the feed network to feed 2×2 antenna sub arrays. The 6×6 antenna array achieves VSWR < 2 bandwidth of 26% for Port 1 and 28% for Port 2. The 6×6 antenna array has measured gain of 22 dBi at 5.8 GHz with isolation between two orthogonal ports > 30 dB.

In this work, a library of 3D lumped components completely embedded in the thinnest, multilayer LCP (M-LCP) stack- up with four metallization layers and 100 μm of total thickness, is reported for the first time. A vertically and horizontally interdigitated capacitor, realized in this stack-up, provides higher self resonant frequency as compared to a similarly sized conventional parallel plate capacitor. Based on the above mentioned library, a miniaturized bandpass filter is presented for the GPS application. It utilizes mutually coupled inductors and is the smallest reported in the literature with a size of (0.035×0.028×0.00089)λ_g. Finally, the same filter realized in a competing ceramic technology (LTCC) is compared in performance with the ultra-thin M-LCP design. The M-LCP module presented in this work is inherently exible and offers great potential for wearable and conformal applications.

In this paper, general solution for the electric and magnetic fields are developed using the vector potentials A and F when the wave is propagating in fractional dimensional space. Different field configurations can be analyzed using the developed expressions for electric and magnetic fields, here we have analyzed TE_z and TM_z modes when the wave propagates in fractional space inside a rectangular waveguide. It is observed that wave propagation behavior in fractional space changes substantially from the non-fractional space. It is also observed that the obtained results show generalization of the concept of solutions for wave propagation from integer to fractional space. As a special case, when all the dimensions are considered integer, then all classical results are recovered.

The Blumlein transmission line (BTL) has broad applications in pulse modulation, microwave technology and pulsed power technology. In this paper, a new theoretical method for variable reflection and transmission of electromagnetic waves at the inductive port of transmission line is put forward, in order to analyze the wave reflection characteristics of BTL at the inductive port formed by a saturated magnetic switch. At the inductive port, the variable reflection and transmission mechanisms of the voltage waves traveling through the BTL are analyzed in detail, and the inductive effects on the square voltage pulse of load formed by the BTL are also studied. Simulation and experimental results both demonstrated the proposed new theoretical method which shows great value on high-power microwave technology, high-power pulse forming, pulse shaping and modulation.

We report the numerical and experimental investigation of a highly directive Fabry-Perot (FP) cavity antenna based on a metamaterial, operating in the microwave regime. Numerical simulations using finite element method and reflection-transmission microwave measurements have been performed and a good quantitative agreement has been observed. Measured return losses and radiations patterns done in an anechoic chamber agree very well with the simulated ones. The potential application of the proposed FP cavity antenna in a non-contact breathing sensor is proposed and evaluated. Experimental record and frequency spectrum for respiratory movements of human-being (voluntary under test) are presented. The low cost and simple fabrication process of the proposed FP cavity antenna make it very promising for its integration in modern telecommunication systems.