The application of spatial filtered FDTD method in fine structures

The Courant-Friedrichs-Lewy (CFL) condition has been considered to be a benchmark that ensures stable electromagnetic modeling while using explicit finite-difference time-domain (FDTD) method. It has been recently shown that the stability limit of FDTD can be surpassed by filtering unstable high frequency components for computational domain within uniform grids. As many models only have fine structure in one direction. According to this, in this paper, a novel spatially filtered FDTD (SF-FDTD) method is developed to get a new normalized cut-off radius of the spatially filtering. The results from the novel SF-FDTD agree well with the results from standard FDTD, and the required CPU time for this method is much shorter than that of the FDTD method.