Superconducting linear phase shifter for the phased array antenna

We propose a continuous variable phase shifter as a new use of a tunable filter. To obtain a large phase shift, the filter is designed using the ideal transform function of the generalized Chebyshev function with real zero. The generalized Chebyshev function with real zero is realized by 4 resonators and jump coupling between resonators. The phase shifter tunes the center frequency by 4 dielectric rods with a piezoelectric actuator. The resonator uses a step-impedance hairpin microstrip line resonator. The phase shifter uses high-Tc superconducting material, YBCO. Therefore, this tunable filter has a low insertion loss of 0.3dB and constant magnitude. In addition, it showed linear phase change continuously. A maximum tuning phase was 372 degrees in condition of a maximum tuning speed of 2.66 msec.