A Novel Weakly Conditionally Stable FDTD Method for Periodic Structures

In this letter, a novel weakly conditionally stable finite-difference time-domain (FDTD) method for solving periodic structures is presented, which is extremely useful for periodic problem with thin slots in one or two directions. To verify the validity of the proposed formulations, a numerical example of electromagnetic band-gap (EBG) structure with thin slots is given. Compared to the alternating-direction implicit FDTD (ADI-FDTD) method, the presented method has higher accuracy and efficiency. Results show the running time can be reduced to about 2/3 of the periodic ADI-FDTD method in the same simulation. To reduce the numerical dispersion error, the optimized procedure is applied.