Design of dual-band microwave duplexers

The design and implementation of dual-band duplexers is presented. The proposed method works well for duplexers with narrow bandwidths and it gives the designers the flexibility to achieve desired return loss levels at different frequency bands. To verify the design concept, dual-band duplexers based on cavity-type resonator topologies are designed, fabricated and tested. Good agreement is achieved between the theoretical synthesis results, the simulation results and the measurement results of the duplexer prototype.