Modeling of generalized coaxial probes in rectangular waveguides

A rigorous approach combining the orthogonal expansion method for modeling cylindrical posts in rectangular waveguides and the extension of the three short plane technique is introduced to obtain the S-matrix for a general coaxial probe in a rectangular waveguide. A cascading procedure is applied to solve the problem of a probe near a waveguide discontinuity and to obtain the response of a probe-excited band pass filter. The computed results are in excellent agreement with the measured results showing the usefulness of this method.