ADMITTANCE OF AN ISOLATED WAVE-GUIDE-FED SLOT RADIATING BETWEEN BAFFLES USING A SPECTRUM OF 2-DIMENSIONAL SOLUTIONS

This paper presents an efficient method of computing resonant length and admittance characteristics of an isolated broad-wall shunt slot, radiating between baffles of finite height. The outer three-dimensional (3-D) field problem associated with this geometry is reduced to a two-dimensional (2-D) one via a Fourier transformation with respect to the longitudinal z direction. For each value of the longitudinal wave number k(z) an integral equation is solved for the E field in the mouth of the plates using the method of moments. This procedure is repeated for several discrete values of k(z), to obtain a spectrum of 2-D solutions which are then inverse-transformed to construct the 3-D solution in the spatial domain for the exterior baffle region and the half space. The slot aperture field is determined by the conventional moment method solution to the integral equation that enforces the continuity of the H field across the slot. Scattering properties of the slot are then deduced. Numerical results for the resonant length and resonant conductance are presented. Computed results are found to be in good agreement with experimentally measured data.