Systematic Design of a Broadband Reflective-Type Phase Shifter with Minimal Loss Variation and High Phase Accuracy

This paper presents a systematic design method of a broadband reflective phase shifter (RTPS) with low phase error and minimal loss variation. In general, RTPS consists of the quadrature coupler and reflective loads. The effect of imperfect quadrature coupler and reflective loads is analyzed in this paper. To verify this theoretical analysis, a RTPS including transformer-based coupler with high coupling coefficient and capacitive reflective loads is designed. This RTPS was implemented in 40nm CMOS technology, that demonstrated the phase shifting range of 61.875°, low RMS phase error of 2° and ultralow loss variation of ±0.14dB from 20GHz to 34GHz. With the advantages of compact chip size (0.028 mm2) and ultralow loss variation, this proposed 61. 875° RTPS can be easily extended to a larger phase shifting range by cascading multiple stages.