Radar cross section from a stack of two one-dimensional rough interfaces in the high-frequency limit

The problem of electromagnetic wave scattering from a rough interface is a non-trivial but rather well-known subject, through the advances made over the last years. The study focuses here on a stack of two rough interfaces (a layer): the objective is to dispose of a fast analytical method which can predict the bistatic radar cross section from a rough layer. The approach used here, which has not been treated before, is the case of very rough surfaces comparatively to the incident wavelength. In this model, the Kirchhoff approximation is used to calculate the field scattered by a rough layer. The first reflection inside the layer is taken into account, in order to determine its contribution comparatively to the field scattered by the upper interface. The shadowing effect, which occurs for grazing angles, is also considered. This model is reduced to the high-frequency limit so as to get numerical results, which are compared with a reference method based on the method of moments