Spectral-Element Spectral-Integral Method for EM Scattering by Doubly Periodic Objects in Fully Anisotropic Layered Media

The spectral-element spectral-integral (SESI) method is developed to simulate the electromagnetic (EM) scattering from doubly periodic anisotropic objects embedded in multiple regions of layered media with the fully anisotropic materials. The SESI is a hybrid method that combines the spectral-element method (SEM) and spectral-integral method (SIM), the computational domain of which is divided into several SEM and SIM subdomains. Different from our previous work, not only the SEM subdomain can be anisotropic but also the SIM subdomain can be anisotropic. This is achieved by extending the periodic layered medium Green's function (PLMGF), plane wave of layered medium, and Riemann transmission condition (RTC) in isotropic materials to those in fully anisotropic materials. Four numerical experiments validate the efficiency and accuracy of the developed SIM and SESI method compared with the finite-element method (FEM) or the analytical solver for plane wave of fully anisotropic layered medium.