A 4-bit CMOS phase shifter for millimeter-wave phased arrays

A 4-bit active phase shifter for millimeter-wave phased arrays is presented in this brief. The proposed phase shifter has achieved a phase-shifting range of with a resolution over 40 to 50-GHz. Thanks to the careful dimension designs of digitally controlled gain stage in the programmable weighted combiner, the active phase shifter achieves root-mean-square phase and gain errors of and 1.25-dB at 45-GHz, respectively. The measurement results also show that the input and output return losses are better than 7-dB from 40 to 50-GHz. The whole chip dissipates only 10.7-mA from 1.2-V supply excluding output driven buffer.