An X-band reflection-type phase shifter (RTPS) with full 360o continuous phase shift, low insertion loss, and low gain deviation using standard 0.15-μm HEMT process is demonstrated in this paper. Two circuit implementation techniques are employed: π-type reflection loads and folded Lange coupler. The π-type reflection loads and the folded Lange coupler are utilized in one stage reflection-type phase shifter to cover more than 180° phase tuning. Cascade of two stage RTPS is adopted to achieve 360° phase tuning. Measurements show signal losses of 6.4dB±1.4dB including pad loss, low gain deviation of 0.8 dB, and a 360° continuously tunable range across 11∼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(°/dB), among all reported 360° X-band CMOS phase shifters.