Low-loss compact MEMS phase shifter for phased array antennas

A compact and low-loss MEMS-based phase shifter is proposed for microwave/millimetre-wave phased array antenna systems. The proposed phase shifter is an alumina-based CPW line, loaded with a variable series capacitor. The phase shifter uses an electromagnetic MEMS actuator to change the capacitor value. A simple three-mask surface micromachining process has been developed for device fabrication. The measurements at 26 GHz show a phase shift of 20°. The overall size of the phase shifter (including the actuator) is 0.5 × 1.5 mm. The measured average insertion loss is 0.75 dB with a variation of 0.4 dB for different phase shifts across the band from 24.5 to 26.5 GHz.