ELECTROMAGNETIC SCATTERING FROM AND TRANSMISSION THROUGH ARBITRARY APERTURES IN CONDUCTING BODIES

The general 3-D aperture coupling problem is formulated in terms of an integral equation for the equivalent magnetic current in the aperture, which is numerically solved by the method of moments. The aperture is characterized by two aperture admittance matrices, one for the exterior region and the other for the interior region. These two admittance matrices are determined separately but in a similar manner if the pseudo-image method is used. Numerically workable expressions are developed for the two aperture admittance matrices by decomposing each of them into a halfspace admittance matrix and a supplementary admittance matrix. The halfspace admittance is relatively easy to compute and has been investigated in the literature. The supplementary admittance matrix is expressed in terms of the generalized impedance matrix of the completed conducting surface (aperture closed). Thus, by combining the existing numerical codes for an arbitrarily shaped scatterer and for an arbitrary aperture in a conducting plane, we obtain a code especially designed for an arbitrary aperture in a conducting surface of arbitrary shape. © 1990 IEEE