Analysis of a solid variable-length cylindrical post in a rectangular waveguide

The problem of a solid cylindrical post in a rectangular waveguide is analysed by an approach in which the electric field off the end of the post is represented as a Gegenbauer polynomial series whose coefficients are determined from the solution of an integral equation by a Chebyshev polynomial approximation process. Numerical results for the fields in the gap region, and the induced current distributions on the surfaces of the post are presented. A comparison between the current distributions of solid and hollow posts is made, and a length-adjustment factor, relating these two posts, is developed. Results for the reactance are shown to be in excellent agreement with experimental measurements