A 0.384 mm2 Ka-Band 4-Bit True Time Delay Phase-Shifters using CMOS Integrated Phase Change Material Switches

This paper describes a CMOS integrated phase shifter using Phase Change Material switches. A 28 GHz, 4-bit 0-321° phase shifter is presented. The complete circuit surface is only 0.384 mm2, including 16 PCM switches, and 4 microstrip delay lines. Two versions of the circuit have been built, one using identical switches, another one using different switch geometries to balance the phase shifter loss. On an amplitude balanced version, the measured loss are between 7.4 and 8.5 dB, leading to a figure of merit of 43.4° per dB.