An Expedient Approach to FDTD-Based Modeling of Finite Periodic Structures

This article proposes an efficient finite-difference time-domain (FDTD) technique for determining electromagnetic fields interacting with a finite-sized 2-D and 3-D periodic structures. The technique combines periodic boundary conditions—modeling fields away from the edges of the structure—with independent simulations of fields near the edges of the structure. It is shown that this algorithm efficiently determines the size of a periodic structure necessary for fields to converge to the infinitely periodic case. Numerical validations of the technique illustrate the savings concomitant with the algorithm.