Scattering and depolarization by rough surfaces near grazing angles--Full wave solutions

Using the full wave approach to rough surface scattering, the apparent singularity in the physical optics and perturbation expressions for the scattered fields is not encountered. The full wave expression for the far fields is shown to vanish in a continuous manner as the observer moves across a shadow boundary. Precise criteria are given for near grazing angles where uniform plane wave excitations cannot be assumed. Comparisons are made between the full wave and the physical optics and perturbation solutions. Since the full wave solution is shown to bridge the gap between the physical optics and perturbation solutions, it accounts for both specular and Bragg scattering. The full wave solutions satisfy reciprocity, duality, and realizability relationships in electromagnetic theory, and they are invariant to coordinate transformations.