Study of EM Scattering from Electrically Large Objects in Planarly Multilayered Media with a Fast Algorithm

摘要

This paper studies electromagnetic (EM) scattering from electrically large objects buried in planarly multilayered media with a fast algorithm, which combines the stabilized biconjugate gradient fast Fourier transform (BCGS-FFT) method with an improved discrete complex image method (DCIM). Filling the table of Green's function and solving the matrix equation constitute two barriers for fast evaluation of EM scattering by buried objects. An improved DCIM is introduced to get a closed-form dyadic Green's function (DGF) in both lossless and lossy multilayered media for the volume electric field integral equation (EFIE), which is accurate both in the near- and far-field regions in layered media without any quasi-static and surface-wave extraction. In the simulation, a split scheme is adopted to avoid applying the improved DCIM repeatedly. By splitting spectral DGF before utilizing the improved DCIM, we need to apply the improved DCIM for only several times. Then, the iterative solver the BCGS-FFT method is combined with the improved DCIM for solving the matrix equation. Numerical results show that the improved DCIM can save tremendous CPU time in scattering problems involving buried objects. The fast algorithm proves effective for EM scattering from electrically large objects in both lossless and lossy multilayered media.