Two-layered rough surfaces modeling based on the physical optics in terahertz gap

In this paper, an approximation iterative model based and a semi-empirical approximation model based on equivalence principle in the terahertz gap are described for predicting the bistatic normalized radar cross section of a homogeneous layer made up of two rough interfaces which have the same profiles. The model of two interfaces can be substituted with one interface by replacing the Fresnel reflection coefficients to equivalent reflection coefficients to get the efficiency improved. This model is valid for thin layer and low incidence angles. Results are presented to validate the model by comparison with iterative physical optics.