摘要:

Time-harmonic electromagnetic fields in a homogeneous biisotropic medium are easily described in terms of Beltrami fields. In this paper, the Mie solution for scattering by an anisotropic impedance sphere immersed in a homogeneous biisotropic medium has been derived, and the effect of impedance-matching conditions examined. The pertinent Rayleigh solution for electrically small spheres has been used to obtain their four polarizabilities, which have been then used to get the Maxwell-Garnett estimates of the effective properties of a dilute random composite formed by immersing electrically small spheres in a homogenous biisotropic host medium.

ISSN:0272-6343    

DOI:10.1080/02726349208908312

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The radiation of an elementary dipole placed inside an infinite triaxial anisotropic medium is analyzed. A Fourier analysis is employed to compute the field which is represented by using a dyadic formulation. The near and far field expressions are obtained by pursuing integration of the Fourier integrals. Conventional spherical scalar wave functions are employed to represent the dyadic Green's functien. Singularity source terms of the Green's function dominant in the near field region, are treated independently. Two separate spherical waves compose the far field, where also a non-zero radial term appears.

ISSN:0272-6343    

DOI:10.1080/02726349208908313

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Two-dimensional scattering from a periodic surface with a wedge profile is treated for both TE and TM polarization. The Interface can be either perfectly conducting or penetrable, and the extended boundary condition (EBC) is used in both cases. The method results in simple matrix elements and is easy to apply. Comparison with a perturbation solution shows that the EBC method has greater accuracy and a greater range of validity. Even so, EBC becomes numerically ill conditioned for surface heights that are a significant fraction of the period or the wavelength. Numerical results are presented for conservation of power, and some comparisons are made with previous results for sinusoidal surfaces. Some applications to rf absorber are also presented.

ISSN:0272-6343    

DOI:10.1080/02726349208908314

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Plane wave scattering from a polygonal plate is investigated within the framework of extended Physical Optics. Reflection and transmission coefficients are used to describe the scattering behavior of various plates, including perfectly reflecting, semi-transparent and perfectly absorbing plates. A far field scattered by such plates is the sum of corner waves. A new asymptotic feature of these waves has been established. The algebraic sum of their directivity patterns is zero for any direction of scattering. Thus the scattering is due to relative phase shifts between corner waves.

ISSN:0272-6343    

DOI:10.1080/02726349208908315

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The subject of this paper i9 a numerical technique for the analysis of the scattering from arrays of conductors of arbitrary shape; in all that follows it will be termed the natural current expansion (NCE). The NCE is a Galerkin’s procedure in which the basis and test functions are the natural mode currents which arise in the singularity expansion method (SEM) framework; the coefficients of the expansion of the induced current in natural modes are determined in order to yield the correct boundary conditions at the conductor surface. The NCE has been successfully applied to the two-dimensional TE scattering from cylinders of arbitrary shape in two particular cases, both for single elements and for arrays; the results confirm that the accuracy is the same as that of the method of moments (MM) with subsectional basis provided that a careful SEM analysis of the single element has been previously performed. The computer time required for solving array problems is considerably lower for NCE than for MM, and the numerical stability of the solution may be also improved.

ISSN:0272-6343    

DOI:10.1080/02726349208908316

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0272-6343    

DOI:10.1080/02726349208908317

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A summary of the state-of-the-art in the formulation and numerical solution of integral equations in electromagnetics is presented. Following a brief summary of the method of moments, database and software requirements are given for specifying and numerically representing geometries and their electrical characteristics and excitation. While concentrating on the formulation of problems in the frequency domain, issues involved in time domain formulations are are also briefly summarized. Basic principles involved in the formulation of integral equations, including the use of Green's functions and symmetry to simplify the solution procedure, are presented. A class of basis and testing functions is defined which subsumes many of those in common use, and their application to compuational electromagnetics is outlined. Finally, matrix solution methods are summarized. For each of the issues considered, an indication of possible new directions in computational electromagnetics is also given.

ISSN:0272-6343    

DOI:10.1080/02726349208908318

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

This paper contains a overview of the methods used in decomposing solutions to scattering problems onto coarse-grained parallel processors. Initially, a short summary of relevant computer architecture is presented as background to the subsequent discussion. After the introduction of a programming model for problem decomposition, specific decompositions of finite difference time domain, finite element, and integral equation solutions to Maxwell's equations are presented. The paper concludes with an outline of possible software-assisted decomposition methods and a summary.

ISSN:0272-6343    

DOI:10.1080/02726349208908319

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The electromagnetic modeling of packages and interconnects plays a very important role in the design of high-speed digital circuits, and is most efficiently performed by using computer-aided design algorithms. In the past two decades, researchers in the electromagnetic and microwave areas have strived to extend the knowledge of interconnection properties. Their efforts have resulted in models and analytical methods without which the development of reliable design tools would be impossible. Packaging and interconnects nowadays represent a critical area for the design of high-performance digital systems, and the work of these contributors is invaluable. This paper exposes the state-of-the-art in packaging technology and reviews the important steps in the development of analytical models, numerical methods and simulation techniques for the design of high-speed interconnections.

ISSN:0272-6343    

DOI:10.1080/02726349208908320

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Several important developments are reviewed to trace the evolution of microstrip antennas since 1974. Munson‘s 1974 paper [l] seems to have been the beginning of an explosion of work that reports experimental and analytical developments in more than 1000 journal articles. Early developments were guided by the interpretations available from transmission line and cavity models, but later developments of full-wave moment methods provided more accurate analyses for design and development. The capability to obtain circular polarization from single elements and arrays has led to numerous applications in communications while stacked patch antennas utilizing parasitic coupling have done much to alleviate the small-bandwidth restriction of simple microstrip antennas. Coaxial probe and monolithic microstripline feeds have been supplemented by a variety of proximity feeds that provide design flexibility and offer performance alternatives.

ISSN:0272-6343    

DOI:10.1080/02726349208908321

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor