Phase shifters with multiple independently controllable bands utilising frequency‐selective variable gain networks

Abstract

A dual-band vector-sum phase shifter with independent phase control of the 2.4 and 5 GHz Wi-Fi bands is presented. The network uses band-limited variable gain amplification, with a broadband hybrid coupler at the input and an in-phase recombiner at the output. The circuit is prototyped on RF printed circuit board and exhibits performance characteristics comparable to the state-of-the-art single band vector-sum phase shifters. The prototype achieved an average gain of 2.16 dB over the 2.4 GHz band, with less than 0.26 dB and 1.32° root-mean-square (RMS) gain and phase error across all 2.4 and 5 GHz band tuning states. In the 5 GHz band, an average gain of 0.17 dB is achieved, with less than 0.21 dB and 3.88° RMS gain and phase error. The network's ability to generate band-independent vector modulation over a 12 dB/90° tuning range is demonstrated as well, achieving less than 0.12 dB and 0.27° RMS gain and phase error in the 2.4 GHz band, and less than 0.27 dB and 2.94° gain and phase error in the 5 GHz band.