Wideband Analysis of Periodic Structures at Oblique Incidence by Material Independent FDTD Algorithm

A novel implementation of the finite difference time domain (FDTD) algorithm to analyze periodic structures over a wideband with oblique incident waves is presented. Based on the field transformation treatment, the method splits each component of the transformed fields of the electric displacement vector and the magnetic induction intensity vector into three parts in a simple manner. This treatment is independent of material and easily implemented, so that it could be utilized in a wide range of periodic structure analysis. The advantage of the method is demonstrated through two numerical examples. One is Jerusalem cross frequency selective surfaces (JCFSS) with anisotropic lossy media in the millimeter wave band, and excited by the TM wave at θ = 20° and the TE wave at θ = 45°, respectively. Another is a photonic periodic structure with rectangular holes for the visible and infrared bands, where it acts as a dispersive medium, with the incident TE plane wave at θ = 30°. The results are in good agreement with those of CST Microwave Studio, and thereby the validity of the method is verified.