A phase and power difference detection technique using symmetric mixer with input level switching for millimeter-wave phased-array calibration

Methods for detecting phase and power difference by using a mixer configured with two symmetrically connected unit mixers with delay lines are proposed. The mixer having two detection curves achieves highly accurate phase detection for all phases, compared with a conventional mixer that has the stationary points 0 and π. The accuracy is demonstrated with a 77GHz 2-ch phased array in 65-nm CMOS. The mixer can also detect the power difference with input level switching in the reverse phase.