Development of X-band high temperature superconducting filters

A synthesized design method is proposed to design microstrip band-pass filters. The impact of the box structure to the filter per-formance is considered besides the structure of microstrip. An X-band high temperature superconducting (HTS) microstrip filter for deep space network is designed using this method. The six-pole microstrip band-pass filter at frequency of 9500 500 MHz is realized using TBCCO HTS thin film grown on 0.5 mm thick LaAlO₃ substrate. The filter shows very high rejection of 90 dB in the stopband and extremely low loss less than 0.2 dB. The measured results are close to the simulated results without any post-production tuning.