A 57-to-64-GHz 0.094-mm25-bit Passive Phase Shifter in 65-nm CMOS

Abstract

This paper presents the design of a compact 60-GHz phase shifter that provides a 5-bit digital phase control and 360° phase range for beam-forming systems. The phase shifter is designed using the proposed cross-coupled bridged T-type topology and switched-varactor reflective-type topology. The topologies are analyzed using a small-signal equivalent circuit model. Furthermore, the design equations are derived and investigated. To validate the theoretical analysis, 60-GHz 5-bit 360° phase shifters are designed in a commercial 65-nm CMOS technology. The fabricated 360° phase shifter features good performance of 32 phase states from 57 to 64 GHz with an rms phase error of 4.4°, a total insertion loss of 14.3 ±2 dB, an rms gain error of 0.5 dB, $P_{\text {1 dB}}$ of better than 9.5 dBm, and the power consumption of almost zero. To the best of our knowledge, the designed 360° phase shifter with the size of 0.094 mm2 is the smallest 5-bit passive phase shifter at frequencies around 60 GHz.