Electromagnetic scattering from two-layer rough interfaces in the Kirchhoff approximation

Electromagnetic wave scattering from multilayers consisting of twotwo-layer Gaussian rough surfaces with lossless media isinvestigated in the Kirchhoff approximation (KA), with consideration ofthe shadowing effects. The tapered incident wave is introduced intothe classic KA, and the bistatic scattering coefficient isredetermined. The advantage of this method is that it is faster incomputation than the exact numerical methods. The numerical resultsshow that the bistatic scattering coefficient calculated in the KAis in good agreement with that obtained by using the method ofmoment (MOM) over a most angular range, which indicates the validityof the KA proposed in our paper. Finally, the effects of therelative permittivity, the root-mean-square (RMS) height, thecorrelative length, and the average height between the twointerfaces on the bistatic scattering coefficient are discussed indetail.