A Provably Stable FDTD Subgridding Method with Arbitrary Grid Ratio for Multisale Structures

A stable finite-difference time-domain (FDTD) sub-gridding method is proposed to efficiently and accurately solve three-dimensional electromagnetic problems. The symmetric interpolation operators between coarse and subgridding meshes are carefully designed to confirm long-time stability. In addition, the proposed method supports arbitrary grid ratios and nested subgridding meshes. Results show that its stability can be guaranteed, and the accuracy and efficiency are improved.