The focus of this work was to drive the size and insertion loss of MEMS based phase shifters to an absolute minimum. The work is based on single pole, 4-throw (SP4T) MEMS switches. These novel switches were then applied on the development of low-loss, miniature 2-bit and 4-bit phase shifters. All designs are carried out on 8-mil thick GaAs substrates, a similar substrate typically used for X-band amplifier designs. Measurements indicate an insertion loss of -0.6 dB at 10 GHz for the 2-bit design, and excellent linear phase response and return loss from DC to 18 GHz. The chip area is 9.6 mm2, and is the smallest reported to-date. The 2-bit phase shifter performed well from DC-18 GHz, with -0.8dB insertion loss at 18 GHz and a return loss of -10.5 dB over DC-18 GHz. The 4-bit phase shifter based on SP4T switches resulted in a measured average insertion loss of -1.1 dB at 10 GHz, and a linear phase shift response from DC to 18 GHz. The chip area is 21 mm2. This is the highest performing 4-bit phase shifter to-date at X-band, using any technology.
