Scattering cross sections for composite random surfaces: Full wave analysis

The full wave approach to rough surface scattering is applied to composite models of rough surfaces. In this work the principal distinguishing feature of the individual rough surface is its correlation distance. Thus this model can be applied to scattering by rough seas as well as by hilly terrain. It is shown that the full wave approach accounts for both specular scatter and Bragg scattering. The scattering cross section for the composite surface, with two or more roughness scales, is shown to be a weighted sum of the scattering cross sections for the individual rough surface heights. Shadowing effects are accounted for explicitly in the analysis. The full wave solutions satisfy reciprocity, duality, and realizability relationships in electromagnetic theory.