EFFICIENT AND ACCURATE FINITE-DIFFERENCE TIME-DOMAIN ANALYSIS OF RESONANT STRUCTURES USING THE BLACKMAN-HARRIS WINDOW FUNCTION

In this paper, we present a technique, based on the principle of the f requency-domain convolution of a time-domain signature and a truncatio n window function, to process the electromagnetic field solution in a resonant structure derived by using the finite-difference time-domain (FDTD) algorithm. We show that the rise of this technique enables us t o substantially reduce the total number of iterations provided that ce rtain criteria are imposed on the time and frequency resolutions, as w ell as on the Nyquist sampling rate. The conventional approach to term inating the time iteration is to employ a rectangular windowing (RGW), which induces the unwanted Gibbs phenomenon in the frequency domain. To avoid this, we apply the Blackman-Harris window (BHW) function whic h modulates as well as truncates the computed time-domain electromagne tic signals. We demonstrate via a numerical experiment that the BHW mo dulation and truncation yield excellent results with only a small numb er of iterations, often only one-tenth of that needed in the RGW metho d. (C) 1997 John Wiley & Sons, Inc.