An Efficient Spectral WLP-FDTD Algorithm for Periodic Structures

An efficient weighted Laguerre polynomials based spectral finite-difference time-domain scheme for 2-D periodic structures is proposed in this communication. By replacing the conventional single-angle incident wave with a constant transverse wavenumber wave, the periodic boundary condition can be directly implemented in the time domain for both oblique and normal incident waves. The huge sparse matrix is transformed into one tridiagonal matrix and one untridiagonal matrix by adding a perturbation term. Then, an iterative procedure is introduced to eliminate the error. Results from the numerical example and HFSS have verified the accuracy and efficiency of the presented method.