W-band piezoelectric transducer-controlled low insertion loss variable phase shifter

A low-cost and low-loss piezoelectric transducer-controlled phase shifter for millimetre-wave/sub-terahertz applications is presented. The proposed idea is based on reducing the propagation constant of a high-resistivity silicon image guide by a high dielectric constant slab loading. The proposed phase shifter has a measured insertion loss of <;-2 dB across the range from 87 to 94 GHz. A phase shift of 85° at 90 GHz is obtained by a device length of 4 mm. The proposed phase shifter has an insertion loss variation of <; 0.2 dB for 85° of phase shift at 90 GHz. Measurement results are in good agreement with the simulations.