Computation of transient electromagnetic waves in inhomogeneous media

Abstract

A brief summary of the methods of solving transient electromagnetic wave problems in inhomogeneous media will be given. The two distinct general techniques, which are the inverse Fourier transformation of time‐harmonic solutions and the direct time‐domain formulation, will be illustrated by way of two examples. In the first example, an efficient numerical mode‐matching method to obtain the response of an electromagnetic source in a two‐dimensional cylindrical inhomogeneity is described. Using this method, the solution is first obtained in the frequency domain. The time‐domain solution is then found by inverse Fourier transforming the frequency‐domain solution. In the second method, a finite‐difference scheme is used to find the transient response of a point source in a two‐dimensional inhomogeneity. Two different methods are proposed to treat the source region singularity. Transmitting boundary conditions are applied on the walls of the finite difference grid so that a finite‐sized box can be used to model an infinite region.