Method of Moments Analysis of Electromagnetic Transmission Through an Arbitrarily Shaped 3D Cavity in a Thick Conducting Plane

The method of moments (MOM) with surface equivalence principle is used to numerically solve the problem of electromagnetic scattering from and transmission through an arbitrarily shaped 3D cavity in a thick conducting plane is considered. The conducting walls of the cavity inside the ground plane are of arbitrary shape. The apertures at both ends of the cavity are also of arbitrary shape. An equivalent surface magnetic current placed on the top aperture produces the scattered field in the region where the impressed sources are. The total field inside the cavity is produced by two surface equivalent magnetic currents on the apertures and an equivalent surface electric current residing on the walls of the cavity as well as on both apertures. The transmitted field on the opposite side of the impressed sources is computed by an equivalent surface magnetic current residing on the bottom aperture. Computed results are compared with results in the literature obtained by using other methods. Very good agreement is observed.