A Comparison of Surface Integral Equation and FDTD Methods for Modeling Backscattering From Dielectric Rough Surfaces at Near-Grazing Angles

A comparative study is carried out between two numerical simulation techniques-the surface integral equation (SIE) and the finite-difference time-domain (FDTD) methods-in order to characterize rough surface ground clutter relevant to forward-looking radar applications. Computational deficiencies in the SIE approach for analyzing scattering effects at grazing angles are outlined; motivations for the development of the FDTD algorithm are presented; subsequently, the FDTD implementation is benchmarked with the SIE method for one-dimensional surfaces for various surface parameters and incidence angles through a comparison of Monte Carlo scattering results. Simulations of two-dimensional random surfaces with a parallelized FDTD method are also featured. This study is intended to facilitate ongoing investigations into the detectability of ground targets at low-grazing angles.