A Compact Dual-Band Bandpass Superconducting Filter Using Microstrip/CPW Spiral Resonators

A compact eight-pole dual-band bandpass filter is designed using a combination of microstrip and coplanar waveguide spiral resonators. To implement a coupling matrix with both large and small elements, four coupling paths are used to apply coupling coefficients varying from 0.001 to 0.3. The fabricated superconducting filter exhibits high performance and excellent agreement with simulations.