Analysis of a right isosceles triangular waveguide fed longitudinal slot antenna

A right isosceles triangular waveguide fed longitudinal slot has been analysed in this Letter by employing the method of moments. The internal admittance has been evaluated by using the image technique to simplify the problem from that of a slot in a triangular waveguide wall to that of two slots in a square waveguide, one each in an adjacent wall. A triangular waveguide has been fabricated and measurements have been taken on slots cut in one of the two equal sides of the triangular waveguide. It has been shown that the theoretical results agree well with the measured results. The theory is useful in the design of triangular waveguide fed slot arrays.