Compact wide-band ridge waveguide dual-band filters

A compact wide-band, dual-band filter realized in air filled metallic ridge waveguides is proposed. Dual-band filters replace doubly multiplexed filters, thus simplifying the system architecture considerably. The filter is realized in a canonical folded structure layout. Coupling sections that realize strong coupling values required for the wide-band characteristics are achieved by means of transversal sections of ridges connecting the main ridge waveguide resonators. The filter is efficiently modeled using rigorous mode matching method. The filter response is further verified using a commercially available Finite Element Method software. In addition a prototype was built and tested for verification.