Fabrication of HTS hairpin type filter with the center frequency of 22 GHz

In order to investigate the possibility of the fabrication of millimeterwave HTS devices, we have designed and fabricated hairpin type filters with the center frequency higher than 20 GHz using YBCO superconducting thin films. The use of high-temperature superconducting (HTS) films in microwave applications provides a realization of high performance planar filters with narrow passband and low insertion loss. We have designed and fabricated 3-pole HTS hairpin type bandpass filters with the center frequency of 22 GHz. In order to reduce the filter size, filter was designed consisting of hairpin type coupled lines. Epitaxial YBCO films were grown on a MgO substrate by pulsed laser deposition (PLD). The film thicknesses were about 500 nm. Superconducting transition temperatures have shown to be about 89 K. Filter shows the insertion loss of 2.8 dB and the bandwidth of about 3 GHz at 77 K. Also the performance of superconducting bandpass filter will be compared with the simulation result.