Sources for total-field/scattered-field formulation in FDTD simulation using approximations to dispersion equation

A full set of numerical wave number k that includes imaginary part as function of frequency can now be obtained by a simple procedure which does not involve numerical root-finding scheme. FFT computation and data storage for the entire time sequence of all fields along the grids can also be avoided by approximating frequency domain inverse transform. The results of the initial numerical simulation are encouraging but are limited by the numbers of terms in the derivative expansions. Other numerical approximations are being investigated and these will be the focus of the presentation.