Scattering from a class of randomly rough surfaces

Abstract

This paper develops new results pertaining to electromagnetic scattering from perfectly conducting random surfaces for which decorrelation does not imply statistical independence. Using an exact theory for the current induced on the surface and the far‐field approximation for the scattered field, it is shown that the incoherent scattered power consists of two parts. The first part corresponds to the so‐called diffuse scattered power. The second part is specular in its angular dependence and is a direct consequence of the fact that the two‐point joint density for the surface height, slopes, etc., does not reduce to the product of the single‐point joint densities for infinite separation distances. Computations for a gently undulating jointly exponentially distributed surface show that the incoherent specular power is equal to coherent scattered power for the Rayleigh parameter near 1. When the Rayleigh parameter is large, the incoherent specular power is significantly larger than the coherent power. The analysis further indicates that scattering measurements provide an ideal way for identifying this class of surfaces.