5 GHz HTS power filters with TM-mode microstrip-disk resonators

For RF wireless applications, high-temperature superconducting (HTS) microwave power filters are desired to satisfy the requirements of higher power handling capability, lower intermodulation distortion (IMD), and dimensions that are more compact. In this report, we propose a 5 GHz HTS band bandpass filter (BPF) that has 2 dual-mode resonators using TM₁₁-mode microstrip-disk (MD) resonators and waveguide line for electromagnetic (EM) coupling between the MDs. The BPF sample with YBCO films on both sides of an MgO (1 0 0) substrate was fabricated, and their RF characteristics of the S parameters, the power, and 3rd IMD (IMD3) were examined. The filter sample exhibited an IMD3 value less than -70 dBc at 10 W input power, and was estimated the half volume of a conventional 4-pole MD BPF