Green's Functions for an Anisotropic Medium: Part 1. Unbounded Case


Book Description

Dyadic Green's Function (DGF) for layered anisotropic media is essential for the electromagnetic field analysis of several problems. With the goal of deriving the DGF of a two-layer biaxially anisotropic medium we derive in this report the DGF of a corresponding unbounded problem. Using the Fourier transform method, an auxiliary dyadic Green's (ADGF) is first derived. The DGF is then obtained by performing a simple linear transformation on the ADGF. It is expressed in a compact dyadic form in terms of two characteristic waves, viz., the a-wave and the b-wave. Some features of the DGF are discussed by comparing our results with those of a corresponding uniaxial problem. Green's function, Electromagnetic waves, Anisotropic medium.




Green's Functions for an Anisotropic Medium. Part 2. Two-Layer Case


Book Description

The Dyadic Green's Functions (DGF) of a two-layer biaxially anisotropic medium are derived. The principal coordinate system of the anisotropic medium is allowed to have arbitrary orientation with respect to the layer geometry. The formulation is based on the unbounded Dyadic Green's Function derived in Part I of the sequel. Using the matrix method the coefficients of the two-layer DGF are expressed in terms of half-space Fresnel reflection and transmission coefficients. To complete this procedure the various relevant half-space Fresnel coefficients are derived. The form in which the results are presented has a physically meaningful and compact structure. A numerical example is provided where we have computed the reflectivities.




Dyadic Green Functions in Electromagnetic Theory


Book Description

In this comprehensive, new edition, Chen-To Tai gives extensive attention to recent research surrounding the techniques of dyadic Green functions. Additional formulations are introduced, including the classifications and the different methods of finding the eigenfunction expansions. Important new features in this edition include Maxwell's equations, which has been cast in a dyadic form to make the introduction of the electric and magnetic dyadic Green functions easier to understand; the integral solutions to Maxwell's equations, now derived with the aid of the vector-dyadic Green's theorem, allowing several intermediate steps to be omitted; a detailed discussion of complementary reciprocal theorems and transient radiation in moving media; and the derivation of various dyadic Green functions for problems involving plain layered media, and a two-dimensional Fourier-integral representation of these functions. This in-depth textbook will be of particular interest to antenna and microwave engineers, research scientists, and professors.




Static Green's Functions in Anisotropic Media


Book Description

This book presents the theory on static Green's functions in anisotropic magnetoelectroelastic media and their detailed derivations via different methods.










Efficient Asymptotic Closed Form Approximation for Dyadic Green's Function for Anisotropic Substrates


Book Description

An efficient closed form asymptotic representation for a grounded double-layered anisotropic uniaxial geometry is developed. The large parameter of this asymptotic development is directly proportional to the lateral separation between the source and observation point. However the asymptotic solution remains accurate even for very small (a few tenths of a wavelength) lateral separation of the source and field points. the asymptotic closed form dyadic Green's function has been cast in such a form that the physical behavior of the electromagnetic fields due to anisotropy of the medium reveals itself through a simple mathematical parameters. Thus, the physical understanding of the interaction of the spatially confined source with an anisotropic (uniaxial) double-layered grounded slab is greatly enhanced through the newly developed asymptotic closed form representation of the dyadic Green's function. Also, this efficient representation is very useful in the moment method (MM) solution of the current excited on the microstrip antennas and arrays in a grounded double- layered uniaxial geometry, as well as the volumetric current excited within a dielectric scatterer buried in a grounded double layered anisotropic uniaxial slab. The MM analysis, especially for microstrip arrays and guided wave structures, requires a very large number of computations where the lateral distance between the source and the field points in the dyadic Green's function can range from extremely small to very large values.




Spheroidal Wave Functions in Electromagnetic Theory


Book Description

The flagship monograph addressing the spheroidal wave function and its pertinence to computational electromagnetics Spheroidal Wave Functions in Electromagnetic Theory presents in detail the theory of spheroidal wave functions, its applications to the analysis of electromagnetic fields in various spheroidal structures, and provides comprehensive programming codes for those computations. The topics covered in this monograph include: Spheroidal coordinates and wave functions Dyadic Green's functions in spheroidal systems EM scattering by a conducting spheroid EM scattering by a coated dielectric spheroid Spheroid antennas SAR distributions in a spheroidal head model The programming codes and their applications are provided online and are written in Mathematica 3.0 or 4.0. Readers can also develop their own codes according to the theory or routine described in the book to find subsequent solutions of complicated structures. Spheroidal Wave Functions in Electromagnetic Theory is a fundamental reference for scientists, engineers, and graduate students practicing modern computational electromagnetics or applied physics.




Waves and Fields in Inhomogenous Media


Book Description

Electrical Engineering/Electromagnetics Waves and Fields in Inhomogeneous Media A Volume in the IEEE Press Series on Electromagnetic Waves Donald G. Dudley, Series Editor ".it is one of the best wave propagation treatments to appear in many years." Gerardo G. Tango, CPG, Consulting Seismologist-Acoustician, Covington, LA This comprehensive text thoroughly covers fundamental wave propagation behaviors and computational techniques for waves in inhomogeneous media. The author describes powerful and sophisticated analytic and numerical methods to solve electromagnetic problems for complex media and geometry as well. Problems are presented as realistic models of actual situations which arise in the areas of optics, radio wave propagation, geophysical prospecting, nondestructive testing, biological sensing, and remote sensing. Key topics covered include: * Analytical methods for planarly, cylindrically and spherically layered media * Transient waves, including the Cagniard-de Hoop method * Variational methods for the scalar wave equation and the electromagnetic wave equation * Mode-matching techniques for inhomogeneous media * The Dyadic Green's function and its role in simplifying problem-solving in inhomogeneous media * Integral equation formulations and inverse problems * Time domain techniques for inhomogeneous media This book will be of interest to electromagnetics and remote sensing engineers, physicists, scientists, and geophysicists. This IEEE Press reprinting of the 1990 version published by Van Nostrand Reinhold incorporates corrections and minor updating. Also in the series. Mathematical Foundations for Electromagnetic Theory by Donald G. Dudley, University of Arizona at Tucson This volume in the series lays the mathematical foundations for the study of advanced topics in electromagnetic theory. Important subjects covered include linear spaces, Green's functions, spectral expansions, electromagnetic source representations, and electromagnetic boundary value problems. 1994 Hardcover 264 pp ISBN 0-7803-1022-5 IEEE Order No. PC3715 About the Series The IEEE Press Series on Electromagnetic Waves consists of new titles as well as reprints and revisions of recognized classics that maintain long-term archival significance in electromagnetic waves and applications. Designed specifically for graduate students, practicing engineers, and researchers, this series provides affordable volumes that explore electromagnetic waves and applications beyond the undergraduate level.