A one-dimensional demonstration of the finite difference time domain technique using a personal computer

The finite-difference time-domain technique for solving Maxwell´s equation is considered. Referring to K.S. Yee´s paper (1966), it is quite straightforward to reduce the finite-difference equations presented there to a one-dimensional geometry. This reduction still allows full control of the constitutive parameters at each cell, so that the result is the capability to analyze propagation through a planar stratified medium for normal incidence. Since the problem space is limited to one dimension, problem geometries involving, for example, reflection and transmission for a stratified slab several wavelengths thick may be computed with a simple Fortran program using a PC/AT or compatible computer with a coprocessor chip in just a few seconds. The one-dimensional formulation does allow specification of permittivity, permeability, and conductivity independently for each layer (cell), so the PC computations can be used to illustrate propagation through and reflection from lossy media. Furthermore, the constitutive parameters can be changed gradually to model the effects of tapering.<>