IE-DDM-FFT for EM scattering by objects in half-space structures

In this paper, an extension of the integral equation based on domain decomposition method (IE-DDM) is presented for dynamic electromagnetic scattering problems above a lossy half space. In the framework of the IE-DDM, the proposed method divides the composite object into several homogeneous sub-domains. Each sub-domain is properly described by a closed surface, and robin transmission condition is introduced to weakly enforce the continuity of tangential field across the touching-face between adjacent sub-domains. Multiple-grid precorrected fast Fourier transform (MG-pFFT) is adopted in each sub-domain independently to account for the self-interactions. Numerical experiments validate the accuracy and efficiency of this method.