Rough surface scattering using specular point theory

The expression for the average scattering cross section for a random surface is derived using the stationary phase approximation for the scattered field due to specular points on a finitely conducting rough surface. A previous error in the literature is corrected by showing that the proper result is proportional to the average value of the product of the number of specular points per unit area and the principal radii of curvature at the specular point, rather than the product of the average value of the number of specular points and the average value of the radii of curvature. When the correct expression for the average value of the product is inserted in the expression for the scattering cross section, the result is in total agreement with the answers obtained when the averaging and stationary phase processes are interchanged. This analysis explicitly accounts for shadowing.