High rejection filters for 5 GHz concurrent dual-radio WiFi

This paper deals with the design of a high rejection microwave notch filters using a low cost planar technology. Thanks to these filters, it is possible to use concurrently in the same device two radios both operating in the 5 GHz WiFi band. The proposed filter topology, based on properly cascading embedded open-circuited stub resonators, shows a good behavior in terms of steepness and out of band response in spite of its relative compactness. Measured performances of a realized diplexer using the designed filters showed interesting results in agreement with simulations.