A scalable baseband phase shifter with 12 GHz I/Q Mixers in 40-nm CMOS for 60 GHz applications

This paper presents a scalable baseband phase shifter implemented in a 40-nm CMOS technology for phased array applications. The baseband phase shifter makes use of the quadrature signals available from the I/Q mixers. By using a resistor chain at the load of the mixer, uniform levels of I and Q signals can be selected by means of gm-cells that can be enabled individually for realizing different phase and amplitude combinations. The proposed phase shifter architecture is scalable in resolution without increasing power consumption. The whole circuit provides 6.6 dB conversion gain, with a total power consumption of 14.7 mW. It achieves in total 225 constellation points for phase and amplitude tuning. It is suitable for accurate beamforming in phased arrays.