Investigation of a scatterer coupled to an aperture in a conducting screen

The paper presents an investigation of the general problem of determining the current induced on a scatterer located on one side of an aperture-perforated conducting screen caused by specified impressed sources. Coupled integrodifferential equations are derived in the paper for a general conducting scatterer and an aperture of arbitrary shape, under the usual assumption that quantities of interest vary harmonically with time and with full account taken of the coupling between the aperture and the scatterer. An alternative formulation of the above-mentioned equations is presented from a point of view which enables one to readily derive equations appropriate for the class of problems under consideration here by simple modifications of the usual aperture-in-a-screen (no scatterer) and scatterer-above-a-screen (no aperture present) equations. It is shown how, taking advantage of the known polarisabilities available in the literature for apertures of numerous shapes, one can greatly simplify the aperture/screen-scatterer equations. The general equations are particularised to aperture shapes and scatterers of interest, and these special-case equations are solved numerically. Data are presented for selected cases.