Full-Wave Characterization of Rough Terrain Surface Scattering for Forward-Looking Radar Applications

In characterizing ground surface clutter as relevant to forward-looking radar applications, a finite-difference time-domain (FDTD)-based solver is proposed to study dielectric surface scattering at low depression angles. The solver's effectiveness and accuracy are carefully evaluated for one-dimensional surfaces by comparing Monte Carlo scattering results to those from a surface integral equation (SIE) approach for various surface parameters and incidence angles. It is demonstrated that satisfactory results can be attained at near-grazing angles for most surface parameters of interest with a relatively small simulation domain size, independent of the incidence angle. Subsequently, FDTD simulations of two-dimensional terrain surfaces are featured, along with a demonstration of the effects of ground clutter on target imaging generated by the time-reversal technique. By providing a practical full-wave simulation framework for the emulation of forward-looking radar operation and imaging, this study is intended to facilitate ongoing investigations into the detectability of discrete ground targets in the presence of distributed variable ground clutter in the near-grazing regime.