A multiple-grid p-FFT with IE-DDM for analyzing scattering from structures above a half space

In this paper, a multiple-grid precorrected fast Fourier transform (MG-pFFT) based on the integral equation domain decomposition method (IE-DDM) is presented for multi-scale, dynamic electromagnetic scattering problems in half space. In the framework of the IE-DDM, the proposed method employs multiple auxiliary FFT grids in each domain. Numerical experiments validate the reduced complexity and accuracy of this method. It is also shown that the proposed method is an efficient and robust preconditioner for the original IE system in half space.