Backscattering and emission signatures of randomly rough surfaces based on IEM

The verification of backscattering signatures of randomly rough surfaces based on the IEM model was conducted through comparisons with 2D simulation by the moment method and 3D simulation by FD-TD and laboratory controlled experiments using a statistically known surface. It has been demonstrated that the standard Kirchhoff and small perturbation models are special cases of the IEM in the high and low frequency regions respectively. In this study the authors apply the IEM model to study the backscattering and emission characteristics of randomly rough surfaces. It is found that because the backscattering coefficient is defined in terms of the noncoherent scattering component of the surface, it is very sensitive to surface roughness. On the other hand surface emission is based on the total emitted power which includes both coherently and noncoherently emitted components. Hence, whenever the surface permittivity is less than 4, the coherent component is dominating and emission is not sensitive to horizontal surface roughness scale. Instead, it is strongly affected by the permittivity of the surface and its vertical scale roughness