An X-Band Full-360° Reflection Type Phase Shifter with Low Insertion Loss

An X-band reflection-type phase shifter (RTPS) with full 360 degrees continuous phase shift, low insertion loss, and low gain deviation using standard 0.15-mu m HEMT process is demonstrated in this paper. Two circuit implementation techniques are employed: pi-type reflection loads and folded Lange coupler. The pi-type reflection loads and the folded Lange coupler are utilized in one stage reflection-type phase shifter to cover more than 180 degrees phase tuning. Cascade of two stage RTPS is adopted to achieve 360 degrees phase tuning. Measurements show signal losses of 6.4dB +/- 1.4dB including pad loss, low gain deviation of 0.8 dB, and a 360 degrees continuously tunable range across 11 similar to 13 GHz with 0-mW dc power consumption. To the best of our knowledge, the proposed phase shifter has the highest FOM of 46.2(degrees/dB), among all reported 360 degrees X-band CMOS phase shifters.