Aperture field and circuit parameters of cavity-backed slot radiator

Abstract
The general problem of a cavity-backed aperture radiator is formulated for the tangential electric field in the aperture. The result is used to obtain an integro-differential equation for the special case of a narrow slot backed by a rectangular cavity resonator. This equation is then solved numerically by the method of moments with the proper choice of piecewise sinusoidal basis and testing functions to remove the differential operator in the integrand. Typical numerical results are presented to show the effect of various cavity and slot dimensions on quantities such as voltage distribution along the slot, input impedance, resonance frequency and bandwidth of the antenna.