A Provably Stable SBP-SAT FDTD Subgridding Method Using Staggered Yee’s Grids

A provably stable finite-difference time-domain (FDTD) subgridding method is proposed to efficiently solve the transverse magnetic (TM) problems. By using the summationby-parts simultaneous approximation term (SBP-SAT) technique, the staggered Yee’s grids without sampling additional components on the interfaces is used, and several projection operators are carefully designed to make sure that SBP properties are satisfied. Therefore, its long-time stability is theoretically guaranteed. Numerical results show that it shows significant accuracy and efficiency improvement compared with the traditional FDTD method.