An Ultra-Low Loss 2 B Reconfigurable Superconducting Filter at P-Band

A superconducting resonator, consisting of a microstrip spiral and a 2 b interdigital capacitor array, is proposed. The resonator has a measured unloaded
Q
over 51 000 in all four states. A two-pole reconfigurable superconducting filter at P-band with a fractional bandwidth of 1% is designed with this resonator and fabricated. The measurements show that the tuning range of the center frequency is from 499.4 to 484.9 MHz with insertion losses of less than 0.1 dB in all four states, and are in good agreement with the simulations.