Spectral domain approach to electromagnetic coupling through apertures in planar conducting surfaces

A spectral domain approach to solving planar aperture type problems is described. The method is first formulated for an arbitrary aperture in a conducting plane separating two half-spaces, then applied to the case of a fin-line structure. The formulation is carried out in the spectral domain in terms of the aperture electric field instead of the electric current density on the plane. The TE-TM decomposition of the fields in the spectral domain is used in conjunction with the transmission-line equivalent model to construct the Green's functions associated with the problem.