All-resonator-based waveguide diplexer with cross-couplings

An investigation into new diplexer topologies, based on all-resonator structures with cross-couplings between common resonators (shared by both channels) and branch resonators is reported. This all-resonator structure eliminates the need for separate frequency distribution networks and uses resonators to achieve this functionality. For diplexers based on such all-resonator structures, cross-couplings can be added between the common resonators and branch resonators to achieve some desired specification (e.g. improved isolation). Two diplexer topologies with such cross-couplings are presented. The first topology is implemented at the X-band using waveguide technology. Excellent measurement results verified the proposed topology as well as the design procedure.