A Novel Filtering Phase Shifter with a 180-Degree Phase Shift Using Switchable Electric/Magnetic Coupling

This paper demonstrates a novel filtering phase shifter that utilizes a reconfigurable filter to achieve a 180-degree differential phase shift. The phase shift is electronically controlled by changing the equivalent physical geometry, which enables switching between electric- and magnetic-coupling. The design is verified using a 4.15 GHz bandpass filter made with split-ring resonators. Simulated results show a differential phase shift of 180-degrees with a phase variation span of 11.7-degrees over a 0.5 dB ripple bandwidth of 260 MHz (6.3 % fractional bandwidth) with 1.41 dB of insertion loss.