Compact Tunable Reflectionless Phase Shifter With Wide Bandwidth and Low Phase Deviation

A novel tunable reflectionless phase shifter (TRPS) utilizing the wideband reflectionless structure and two phase compensation techniques is firstly proposed, which offers a wide operational bandwidth, low phase deviation, and absorbed reflections. The operational bandwidth of the reflectionless structure is extended by incorporating independently-controlled resonant poles and low/high cut-off frequencies in the capacitor-loaded coupled structure and inductive absorptive networks, respectively. Furthermore, two phase compensation techniques are employed, including an AC grounded coupled line adopted in the tunable loads for impedance compensation and the inductive absorptive network reused to introduce additional phase, both contributing to low phase deviation. Measurement results indicate that the proposed TRPS features a fractional bandwidth of 116%, a continuously-tunable phase with deviation less than +/- 6.5 degrees, and a continuous reflection absorptivity from DC to 12 GHz.