Abstract
A domain decomposition-finite difference time domain (DD-FDTD) method is proposed to solve the problem of electromagnetic scattering from very large rough surfaces. The entire computational domain is decomposed into multiple subdomains. Each subdomain is simulated by using the conventional FDTD method to obtain the scattered fields on a Huygens' surface and the total fields on the rough surface. The latter is used to compute the scattered field on the Huygens' surface in adjacent subdomains, by invoking the reciprocity theorem. Simulation results are compared with those in the literatures to validate this method. The normalized radar cross sections (NRCSs) from very large surfaces of 66 lambda x 66 lambda are also presented to demonstrate the efficacy of this method.