Note on the Kirchhoff rough surface solution in backscattering

The purpose of this note is to demonstrate that an existing Kirchhoff solution by Beckmann and Spizzichino for the average backscattered power from a randomly rough surface correctly provides frequency dependence for a computer‐generated surface. In addition, it also approaches the geometrical optics solution in the high‐frequency limit. Results indicate that for backscattering near vertical incidence this solution is more general and useful for applications than the geometric optics solution (given by (5) in section 2).