Reflection Phase Shifter for Phased Array Antennas with Digitally Tunable Capacitors

In this paper, a novel wideband reflection type phase shifter (RTPS) for phased array antenna is proposed for the first time using commercial digitally tunable CMOS capacitor. The maximum relative phase shift obtained was about 95 degrees for digital input 00000 to 11111 at 2.8 GHz. The insertion loss in the pass band from 1.5 GHz to 3 GHz is 0.5 dB and the return loss is greater than 20 dB.