Method-of-Moments solution for the Probe-Excited cavity Problem

In order to solve the impedance matching problem encountered in the rectangular waveguide filter design, the corresponding modeling, parameter extracting and designing are presented. The moment method is introduced to analysis the input impedance of the probe located in an arbitrary position of the waveguide broad side, then, with the use of 3 cavities solution, a 2-port scattering matrix is derived. The computed result coincides well with Ji-Fuh Liang´s measured results. At last, an example for a dual-mode waveguide filter verifies the validity of the proposed design.