A Determination of the Electromagnetic Scattering from a Cavity-Backed Plane Surface

摘要

A determination is made of the electromagnetic scattering from an infinite plane surface backed by an infinitely long rectangular cavity. The cavity is coupled through the plane surface by a narrow, infinitely long aperture running parallel to the axis of the cavity. The structure is excited externally by a plane wave of arbitrary polarization and arbitrary angles of incidence. In the formulation given, a pair of singular integral equations governs the behavior of the tangential components of the electric field in the aperture (the aperture fields). The integral equations are solved using a standard perturbation technique under the assumption of a small aperture width in wavelengths. The fields scattered by the structure consist of the superposition of a field specularly reflected from the plane surface and a field reradiated by the induced aperture fields. The spatial distribution of aperture fields is numerically calculated for various cavity dimensions. A simple, approximate technique is outlined for obtaining the component of the aperture field perpendicular to the edge. The results of this technique are briefly compared with the more accurate results obtained from the integral equations. (Author)