Design of E-plane and H-plane Waveguide Filters Using a Genetic Algorithm and Mode-Matching Method

In the conventional method for design of waveguide filters, equivalent circuits such as impedance or admittance inverters are used to model the waveguide discontinuities. These inverters are useful for design of filters with narrow bandwidth. In this paper using a genetic algorithm and mode-matching (MM) method, and without using the equivalent circuits, two E-plane and H-plane bandpass waveguide filters are designed. To verify the validity of MM method, the frequency response of filters is obtained by the PML-FDTD method. The two filters are also analyzed by the HFSS software. The results of MM method are in excellent agreement with the results provided by FDTD method and HFSS software. An important characteristic of a waveguide filter is the sensitivity of its frequency response to fabrication errors. In this paper, by using the Monte Carlo statistical method, sensitivity of the frequency response of E-plane and H-plane filters to fabrication errors are determined and compared with each other.