Stable TDIE-MOT Solver for Transient Scattering by Two-Dimensional Conducting Structures

A new numerical approach for transient scattering by two-dimensional structures using the time domain integral equation (TDIE) method in conjunction with the marching-on-in-time (MOT) scheme is developed. Through proper choice of temporal basis functions and precise evaluations of matrix elements, the approach is unconditionally stable in terms that no extra stabilized measure is necessary. Quadratic B-spline function is employed as the temporal basis function, and closed-form integrals with respect to time are derived for calculating the matrix elements. Three examples with closed, open and coupling structures are examined under illuminations by both TM and TE waves. Numerical validations are illustrated by comparisons with analytical or numerical results in frequency domain via discrete Fourier transforms.