Design and performance of reconfigurable high temperature superconducting filters

Based on the high temperature superconducting (HTS) thin film material DyBCO and electrically tuning varactor, 5-pole reconfigurable superconducting band-pass filter and superconducting band-stop filter working in very high frequency (VHF) band have been designed and developed. The equivalent circuit, theoretical curve, layout design process of the two filters are presented by using the collaborative simulation method. Finally, the simulation results and the actual test curves of the reconfigurable superconducting filter are given. The results show that: (1) the adjustable frequency range of reconfigurable superconducting band-pass filter is 235~250 MHz, and the bandwidth is 0.7 MHz, out-of-band rejection is more than 70 dB; (2) the adjustable frequency range of the band-stop filter is 220~267 MHz, and the stopband width is 1.0 MHz, the passband loss is less than 0.1 dB.