One‐Step Leapfrog 3D Split‐Field <scp>FDTD</scp> Method for Periodic Structures at Oblique Incidence

ABSTRACT This article introduces a one‐step leapfrog three‐dimensional (3D) split‐field finite‐difference time‐domain (SF‐FDTD) method designed for analyzing periodic structures under oblique incidence, aiming to improve computational efficiency. Initially, it introduces new variables to substitute the field components postsplitting. After that, it applies time‐centered approximate difference method to precisely adjust the time step for each iteration. It eliminates the need for empirical coefficients when performing calculations with lossy materials. Finally, it derives the implementation of the convolutional perfectly matched layer (CPML) for the proposed method. The proposed method is both easier to implement and more resource‐efficient, significantly cutting down CPU usage and memory consumption. Numerical results confirm its improved efficiency.