Single Crystal Piezoelectric Actuators for Tunable HTS Filters

This paper presents cryogenic actuators for high‐temperature superconducting (HTS) tunable filters. The designated piezo‐tuned‐HTS concept will enable a broad range of civilian and military applications that require precise band selectivity over a broad frequency range. In this paper, low profile flextensional single crystal actuators were developed with 150‐μm stroke at 77 K. This actuator was then used for Superconducting Technologies, Inc. (STI) HTS resonator tuning in liquid nitrogen. A fine tuning using the same actuator shows more than 3% tunability and less than 1‐dB insertion loss variation and the Q is about a few thousands.