Extension of the scalar Kirchhoff approximation for calculating the coherent scattering from multi-layers with random rough interfaces
Résumé
This paper deals with the electromagnetic wave scattering
from multi-layered media, containing random rough interfaces.
It presents an extension of a basic asymptotic model
called the Kirchhoff-tangent plane approximation (KA) to
multi-layers. In order to be able to derive a simple expression
of the scattered intensity, further approximations must
be made. Here, we focus on calculating only the coherent
contribution to the total scattered intensity and apply the socalled
scalar Kirchhoff approximation that makes it possible
to simplify the mathematical expressions. Last, the random
rough interfaces are assumed to be uncorrelated, so that a
fully analytical expression of the (coherent) scattered intensity
is obtained. Previous work validated this approach; this
paper focuses on analysing the hypothesis of taking only one
reflection inside each layer into account.