Asymptotic Methods in Electromagnetics [Paperback]

Numerically rigorous techniques for the computation of electromagnetic fields diffracted by an object become computationally intensive, if not impractical to handle, at high frequencies and one must resort to asymptotic methods to solve the scattering problem at short wavelengths. The asymptotic methods provide closed form expansions for the diffracted fields and are also useful for eliciting physical interpretations of the various diffraction phenomena. One of the principal objectives of this book is to discuss the different asymptotic methods in a unified manner. Although the book contains explicit formulas for computing the field diffracted by conducting or dielectric-coated objects, it also provides the mathematical foundations of the different methods and explains how they are interrelated.Numerically rigorous techniques for the computation of electromagnetic fields diffracted by an object become computationally intensive, if not impractical to handle, at high frequencies and one must resort to asymptotic methods to solve the scattering problem at short wavelengths. The asymptotic methods provide closed form expansions for the diffracted fields and are also useful for eliciting physical interpretations of the various diffraction phenomena. One of the principal objectives of this book is to discuss the different asymptotic methods in a unified manner. Although the book contains explicit formulas for computing the field diffracted by conducting or dielectric-coated objects, it also provides the mathematical foundations of the different methods and explains how they are interrelated.1. Ray Opties.- 1.1 Introduction.- 1.1.1 The principle of localization.- 1.1.2 Determination of the rays and generalization of Fermats principle.- 1.1.3 The laws of geometrical optics.- 1.1.4 Determination of the diffraction coefficient.- 1.1.5 Summary: The GTD as a ray method.- 1.2 Ray tracing using generalized Fermats principle.- 1.2.1 Condition for a path L to be a ray.- 1.2.2 Lawlss