Analytical formulation of the scattering by a slightly rough dielectric boundary, covered with a homogenous dielectric layer

Characterization of the radar response of a multi-layer dielectric media with slightly rough interface has a number of applications, including remote sensing of snow non-destructive evaluation and quality control of multi-layered MMIC, etc. For the case of snow-pack remote sensing, the premise is to compare the scattered fields of the rough surface with snow with that on bare rough surface and then attribute the variation in the scattered power and coherence to the snow parameters. In this approach, first, the snow cover is modeled by a homogenous dielectric layer having a smooth top surface above a ground plane with a rough surface. In situations where the scattering from the rough surface become comparable to with the snow volumetric scattering, the volume scattering is added incoherently to the surface scattering, and then, the coherence is computed. In this paper, a small perturbation solution is developed to predict the bistatic scattering coefficients and the coherence of a slightly rough surface covered with homogenous dielectric layer.