Design and Fabrication of Superconducting Double Spiral Filter

摘要

This paper reports the design and fabrication of a miniaturized superconducting microstrip line filter using YBCO film on MgO. The filter's resonators are shaped in a double spiral, and the size of the resonators is optimized from the standpoint of the unloaded Q-factor. The 15-pole bandpass filter that has the center frequency of 1.95 GHz and the bandwidth of 20 MHz is designed in the size of 9.7 x 44 mm. The simulated S-parameter characteristics of the filter is corresponding to the initial design parameters. We fabricated the filter on an MgO substrate with a diameter of 2 inches. The filter had very sharp cutoff and a very low insertion loss of 0.14dB.