Bistatic radar cross section of two-dimensional random rough layers in the high-frequency limit

Few fast asymptotic models have been developed on stacks of rough interfaces. Nevertheless, the specific case of very rough surfaces comparatively to the incident wavelength has not been treated before, which is the context of this paper. The model starts from the iteration of the Kirchhoff approximation to calculate the fields scattered by a rough layer, and is reduced to the high-frequency limit in order to fast obtain numerical results. The shadowing effect, important under grazing angles, is taken into account. The model can be applied to any given slope statistics. It is validated by comparison with a reference numerical method based on the method of moments, in the high-frequency limit for lossless and lossy inner media separating ID surfaces. Then, the model is extended to 2D surfaces.