Numerical Study and Optimization of Post-Wall Waveguides and Filters for Millimeter Waves

Functional post-wall waveguides and waveguide based compact passive circuits - namely bandpass filters - that are formed by introducing additional metallic or dielectric posts inside the post-wall waveguide are analyzed. The propagation constant of a post-wall waveguide is experimentally measured and compared with the results obtained using the originally developed numerical method. A good agreement is observed in the whole frequency range. The S-parameters of the waveguide-based bandpass filters are calculated using the image theory combined with the lattice sums technique. The developed formulation is numerically fast, hence it can be considered as one of the best-suited approach for structural topological optimization. Finally, a breeder genetic algorithm is used as a global search heuristic in order to track down the optimal geometrical parameters for the introduced posts yielding a bandpass filter characteristic in the desired frequency bands.