A Stable Hybrid Implicit-Explicit FDTD Subgridding Method for TE Analysis

A stable FDTD subgridding method combining the finite-difference time-domain (FDTD) method and the leapfrog alternately-direction-implicit finite-difference time-domain (ADI-FDTD) method is proposed to accurately and efficiently solve two-dimensional transverse electric (TE) problems. The FDTD method is used in the coarse meshes and the leapfrog ADI-FDTD method in local subgrid meshes, respectively. Spatial interpolation between interfaces of coarse and subgrid meshes are carefully designed. To avoid interpolation in temporal domain and improve the efficiency, one uniform large time step is used in the whole computational domain. Results show that its stability can be guaranteed, and the accuracy and efficiency are improved.