High-Performance Electrically Tunable RF Phase Shifter With the Application of PZT and Permalloy Thin-Film Patterns

A fully electrically tunable RF phase shifter enabled with lead zirconate titanate (PZT) and Permalloy (Py) thin-film patterns based on the step impedance slow wave structure is well designed and fabricated. Tunable metal-insulator-metal structure capacitor enabled with the PZT thin film is integrated into the phase shifter so that the working frequency can be tuned by dc voltage, and the tuning voltage is significantly decreased compared with the previous research. The Py thin film is patterned and is deposited on the signal line of the proposed phase shifter that enables a tunable working frequency by dc current. Both inductive and capacitive tunability of phase shifter are achieved simultaneously. When 200 mA dc current is provided between two ports of phase shifter, the working frequency tuning range is 2% from 1.98 to 2.04 GHz. The tuning range is 5% from 1.98 to 2.08 GHz when 8 V dc voltage is added between the signal line and the ground. When both 8 V dc voltage and 200 mA dc current are applied, the working frequency of the proposed phase shifter is tunable from 1.98 to 2.12 GHz with a tunability of 7.1%.