EFFICIENT MOMENT METHOD ANALYSIS OF RADIATING SLOTS IN A THICK-WALLED RECTANGULAR WAVE-GUIDE

A narrow slot in the broad wall of a rectangular waveguide is analyzed using a moment method which takes account of both the waveguide wall thickness and the influence of side walls. The method of moments is used to solve a pair of coupled-integral equations, derived from the electromagnetic boundary conditions using Green's function techniques, to find the tangential electric fields on the upper and lower surfaces of the slot. These fields are represented by a sinusoidal Fourier set of basis functions. It is shown that only a few terms are required to cause the series to converge. The necessity of inverting large, full matrices, which can be a disadvantage of this method, is thus avoided. Theoretical results are presented for the scattering parameters of slots and these are compared with experiment. A computed curve showing the functional form of the tangential electric field in the slot is compared with earlier calculated and trial slot-field distributions.