A Wideband Tunable Filtering Phase Shifter with Continuous Phase-Control

A wideband tunable filtering phase shifter (TFPS) is presented in this work. The proposed phase shifter uses parallel coupled line stepped impedance resonator (SIR) structure to form the wideband filtering path. The open-ended stub is loaded at the port to introduce a transmission zero (TZ). The tunable part of this work is realized by a tunable phase shift unit (TPSU), which is composed of several varactor diodes at the end of the coupled line. Through analyzing phase characteristics of TPSU and its effect on the circuit, it can be deduced that the phase shifter could control phase shifts continuously. For validation, a wideband TFPS has been designed with an operating frequency range from 1.12 GHz to 2.63 GHz, the simulated results show that this design can control phase shift continuously of more than 180° within wideband fractional bandwidth (FBW) of 80%