A Synchronized Multigrid Time Domain Method Via Huygens Subgridding and Implicit Algorithms

Based upon Huygens´ subgridding (HSG) technique and unconditionally stable time domain algorithms, we present a synchronized multigrid time domain method for 2- and 3-D scattering problems. In this method, the implicit algorithms are employed in the fine grid region, while the Yee-FDTD is marching on the coarse mesh. As a result, the electromagnetic fields in both coarse and fine grid regions are updated synchronously. The synchronization has greatly simplified the HSG implementation and reduced updating substeps. Numerical examples demonstrate extremely low spurious reflection at the interface, robust stability for arbitrarily large spatial ratios, and suppression of late time instability.