A 110 GHz Continuous 220° Phase Shifter Using Passive Feedback Circuit in 40‐nm CMOS Technology

ABSTRACT The circuit mechanism of the feedback phase shifter is clearly analyzed based on microwave network analysis, and then an intuitive design approach is proposed. First, the phase shifting concept beyond the addressed design will be analyzed in terms of Y ‐parameters, and the dependency of the phase on the feedback admittance Y f will accordingly be concluded. A feedback circuit was therefore designed based on an intuitive phase‐magnitude graph, such that the locus of admittance Y f will cross over various phase lines on the plane when tuning the varactor at the feedback. To demonstrate the approach, a phase shifter was designed, which consists of two successive shifter stages for coarse and fine‐tuning that provide 177° and 46° for each stage, respectively, at 110 GHz. The module is adopted in a 1.16 mm 2 size and shows a total DC power consumption of 92 mW.