A Novel FDTD Subgridding Method With Improved Separated Temporal and Spatial Subgridding Interfaces

A novel finite-difference time-domain (FDTD) subgridding method with improved separated temporal and spatial subgridding interfaces is proposed in this letter. In the improved temporal subgridding algorithm, the Taylor expansion is used to obtain the missing magnetic fields at temporal subgridding interface. For improving the stability, the electric fields at temporal subgridding interface and the magnetic fields in subgrid nearest to the temporal subgridding interface are modified at the end of each coarse time. In the improved spatial subgridding algorithm, the loop integrations of magnetic fields in coarse grid nearest to the spatial subgridding interface are amended. With numerical simulation, the efficiency and high late time stability of the proposed method have been verified. Finally, this proposed method could well resolve the difficulty of material traversing the temporal and spatial subgridding interfaces.