Unconditionally Stable FDTD Algorithm Based on Split-Step Scheme for the Analysis of Oblique Incident Plane Wave on Periodic Structures

摘要

In this paper, an unconditionally stable finite-difference time-domain (FDTD) algorithm is presented for solving the problems of oblique incident wave on 2-D periodic structures. By expressing the extra time derivatives caused by the field transformation technique as the form of the coefficient matrix, and applying the split-step scheme (2, 2) (SS2) to the transformed Maxwell's equations, the update at each time step is subdivided into three sub-step implementations. The proposed method has second-order accuracy both in time and space, and the time step size of which is not limited by the Courant-Friedrich-Levy (CFL) stability condition. Compared with the previous approaches of the field transformation method, this technique does not need to introduce additional field components and is more efficient and accurate especially at the large incident angle.