LAUSR

We designed transmit bandpass filters that have a four-pole cascaded quadruplet (CQ) structure with high-temperature superconducting (HTS) bulk disk resonators. We developed a trimming device that can change the electric-coupling coefficients simply by adjusting the height of a pair of copper rods. We analyzed the frequency response of the filters using an electromagnetic simulator and found that the trimming device can provide the targeted value for the coupling coefficient. In addition, from simulation of the filters, we obtained frequency responses with a center frequency of 5.04 GHz, a bandwidth of 124 MHz, and a skirt characteristic of 3.23 dB/5 MHz. To our knowledge, this is the first CQ filter structure yet developed using HTS disk resonators and a trimming system for electric coupling.