The Dipole Moment (DM) and Recursive Update in Frequency Domain (RUFD) Methods: Two Novel Techniques in Computational Electromagnetics

In this paper, we begin by introducing a novel concept for formulating electromagnetic simulation problems that is based on the use of the Dipole Moment (DM) approach, which has several desirable features. First, it circumvents the need to deal with the singularity that is inherently encountered during the process of evaluating the matrix elements in the conventional Method of Moments (MoM) formulation based on the Green's function approach. Second, it handles both dielectric and conducting materials, be they lossy or lossless, in a universal manner, without employing different starting points for the formulation. This enables us to handle inhomogeneous problems in a convenient manner using a single formulation. Third, it does not suffer from the so-called “low-frequency breakdown” problem in the conventional MoM formulation, which is presently handled by using special basis functions, such as the loop-star. Fourth, it enables us to hybridize with finite methods to solve multi-scale problems in a convenient manner

Low-Sar Hexa-Band Antenna For Mobile Applications

In this work, we describe a hexa-band mobile phone antenna with a metallic backing, designed for SAR reduction. The proposed antenna has a simple structure comprising of two radiating strips and a coupling strip which serves to enhance the bandwidth at high frequency. The antenna has been designed to cover multiple bands, namely LTE Band 13 (747-787 MHz); DCS 1800 (1710-1880MHz); PCS 1900 (1850-1990MHz); WCDMA (1920-2170MHz); LTE Band 40 (2300-2400 MHz); and Band 41 (2496-2690MHz). The designed antenna only occupies a small area of 15×29.5 mm2 on the system circuit board. By adjusting the shape, location and size of the backing, the SAR is effectively reduced over all of the bands, while the efficiency of the antenna is preserved. Thus, the antenna is an excellent candidate for incorporation into smart phones for next generation wireless systems

Efficient Analysis Of Scattering By Strip Gratings

Plane wave scattering by a perfectly conducting strip grating is considered. A methodology for the computation of the induced currents is proposed, which utilizes the knowledge of the current induced in the center region of a truncated finite grating with only a moderate number of strips

Volume Integral Equation Analysis of Thin Dielectric Sheet Using Sinusoidal Macro-Basis Functions

In this letter, we present an improvement over the conventional thin dielectric sheet (TDS) formulation for the analysis of thin dielectric sheets. Our focus is to address the problem of scattering from thin penetrable scatterers by developing a volumetric formulation based on the use of macro-basis functions. The electric fields produced by the source basis functions are derived directly, bypassing the summation of scalar and vector potentials. The latter results in a considerable time advantage in comparison to the conventional method of moments (MoM) solution of the volume electric field integral equation (V-EFIE), while the accuracy remains comparable. In contrast to the TDS formulation, both tangential and normal currents are employed so that problems with high and low permittivity, as well as those involving grazing incident angles, can be accurately analyzed. Several examples are reported that show excellent agreement with conventional techniques and demonstrate the effectiveness of the new approac

Analysis of finite conformal frequency selective surfaces via the characteristic basis function method and spectral rotation approaches

An efficient characteristic basis function (CBF)-based method is proposed to analyze conformal frequency selective surfaces (FSS) that are not amenable to analysis by using conventional numerical methods typically used to model infinite, planar, and doubly periodic FSSs. The technique begins by employing the CBFs to describe the currents induced on the elements. The reaction integrals needed to derive the reduced matrix elements are computed either in the spatial domain, or spectral domain, depending on the separation distance between the blocks, so as to make the process numerically efficient. The spectral domain integrals are evaluated by making use of the spectral rotation (SR) on the spectra of the CBFs to alleviate the computational burden to be associated with full three-dimensional (3-D) Fourier transform, which is required in the conventional spectral domain approach applied to nonplanar geometries. Numerical results from the new method have good agreement with the fully spatial characteristic basis function method (CBFM) and the conventional method of moments (MoM). However, the required central processing unit (CPU) time is greatly reduced. © 2002-2011 IEEE