Interference phenomena in scattering by rough interfaces in arbitrary plane-layered media

The authors consider electromagnetic (EM) wave scattering from a rough boundary of a stratified medium with arbitrary dependency of its parameters on a vertical coordinate that could allow refraction of scattered radiation back to the boundary. The roughness is assumed to be small and gentle enough for a small perturbation method to be applicable. Along with the model of layered medium with variations of dielectric permittivity ε(z) only, they also investigate the more general case that includes variations of magnetic permeability μ(z). In this case, the symmetry of the results with respect to electric E and magnetic H fields allows the authors to perform all derivations for one polarization state only. The results for the orthogonal polarization could be obtained by the replacement μ&rlhar2;ε, E→H and H→-E in the final formulae. The plane wave expansion method allows them to avoid cumbersome Green´s function method derivations and to obtain compact expressions for scattering amplitudes and appropriate cross sections not only in free space, but also in layered media such as ice, topsoil, snow, and the sand cover of arid regions