Modeling how electromagnetic waves scatter from a distribution of rough plates poses many applications. Certain systems may be easy to approximate with planar geometry, but use of numerical field solvers to determine the radiated fields could take a long time for nontrivial structures. We propose a new approach based on the Kirchhoff approximation. This method will consider the case of multiple rough, finite-sized rectangular plates. The solution was used for developing software to determine the scattering of waves off of a distribution of rough plates of arbitrary position and orientation between a transmitter and receiver. The method considers each plate individually, calculating the coherent and incoherent scattered fields. Provided that all plates and the transmitter and receiver are sufficiently spaced, we calculate the total fields by summing the result from each individual plate. For many practical situations, the distance from the plate to the receiver may not be much greater than the size of the plate. We will show that the common far-field approximation of the Green's function is not valid for these cases, and we will have to use a more accurate approximation of Green's function.
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