Analysis of Post-Wall Waveguides and Circuits Using a Model of Two-Dimensional Photonic Crystals

A semi-analytical method to analyze post-wall waveguides and circuits based on the model of two-dimensional photonic crystals formed by layered periodic arrays of circular cylinders is presented. The propagation constant of the fundamental TE mode, the attenuation constant due to the leakage loss and the effective width of an equivalent rectangular waveguide are calculated. Using the concept of the effective width, the original structure is replaced by an equivalent rectangular structure. When additional metallic posts are loaded in the rectangular waveguide, functional post-wall waveguide-based passive circuits are formed. The S-parameters of the post-wall circuits, which act as bandpass filters, are calculated using the image theory combined with the lattice sums technique.