Design of a Filtering Non-reciprocal Phase Shifter with Tunable Center Frequency and Independently Bidirectional Phase Tuning Capability

This paper proposes a reconfigurable filtering non-reciprocal phase shifter with tunable center frequency and independently bidirectional phase shifting capability. It has two input/output ports, where the forward and backward amplitude responses are identical, but the phase response differ. The design primarily comprises two co-designed magnet-less filtering circulators integrated with phase control capabilities at its each output ports, connected in a loop via two cables. For proof-of-concept, a circuit prototype is designed, fabricated, and measured, validating the design methodology and demonstrating a continuous phase tuning range of 300° for each transmission direction.