A Stable and Symmetric FDTD Subgridding Method with Arbitrary Grid Ratio

A stable and symmetric finite-difference time-domain (FDTD) subgridding method is proposed to effectively and accurately solve the three-dimensional electromagnetic prob-lems. The linear interpolation coefficient (LIC) and the length cutoff coefficient (LCC) are carefully designed to guarantee the stability of the proposed method. In addition, the proposed method is applicable to arbitrary grid ratios and nested meshes. A practical multiscale example is used to validate its accuracy and efficiency.