A 26-32GHz 6-bit Bidirectional Passive Phase Shifter with 14dBm IP1dB and 2.6° RMS Phase Error for Phased Array System in 40nm CMOS

This paper presents a 26-32GHz 6-bit bidirectional passive vector modulation phase shifter in 40nm CMOS for phased array systems. The passive phase shifter consists of a capacitor-free Lange-coupler based IQ generator and a differemtial power combiner. The symmetric design allows bidirectional signal propagation for flexible system configuration. Sizes of the passive switches are optimized to achieve the optimum trade-off between bandwidth and linearity. The overall phase shifter covers a range of 360° with 5.625° resolution and the RMS phase error is between 1.8° and 2.6°. It exhibits less than 0.22dB magnitude imbalance and <2.5° phase imbalance between forward and inverse propagation mode.