Physical asymptotic model for a conducting patch and how this enables the inclusion of dielectric substrate in a free-space moment method code

The asymptotic field expression, in the spectral domain, of a conducting patch on a multilayer dielectric substrate is derived. It is shown that the corresponding field solution in the spatial domain is equal to that of a patch in a homogeneous region with an effective permittivity. This allows the infinite double integral of the asymptotic part of the method of moments matrix elements to be computed in a homogeneous spatial domain. As a result, the computation time can be reduced considerably. It is shown that a spatial domain MoM code for conducting patches and lines in homogeneous regions can easily be modified to include a multilayer dielectric substrate by adding a correction factor to the matrix elements.