A 60-GHz single-ended-to-differential vector sum phase shifter in CMOS for phased-array receiver

A 60-GHz vector sum phase shifter with single-ended-to-differential function for phased array receiver using 90-nm LP CMOS technology is presented. This phase shifter incorporates a four-way quadrature power divider as a vector generator with two variable gain amplifiers and a vector modulator to achieve full-360° phase synthesizing. For 4-bit operation (22.5° phase resolution) from 57-64 GHz, this phase shifter exhibits a gain error and a phase error for all the 16 states of within 2.5 dB and 11°, respectively. The RMS gain error at the two output ports are both under 1.2 dB, and the RMS phase error is under 10.5°. The RMS gain imbalance and phase imbalance between the differential outputs are under 0.8 dB and 5.2°, respectively. The average gain of one of the differential outputs at 60 GHz is -5.4 dB, and the input and output return losses are both over 10 dB. This chip consumes 34 mW from a 1.2-V supply. The chip size including all the pads is 0.96 × 0.69 mm².