Superconducting microstrip hairpin filter with BaTiO3 patches

A high temperature superconducting microstrip line hairpin filter with BaTiO₃ has been designed and fabricated. The design and the filter simulation were done using Genesys software from Eagleware. In order to maximize the quality factor of the filter, the microstrip lines were made of superconducting YBa₂Cu₃O₇. A YBa₂Cu₃O₇ thin film was deposited on a LaAlO₃ single crystal substrate using pulsed laser deposition. The microstrip line hairpin filter was then patterned and tested at cryogenic temperatures. A BaTiO₃ thin film was then deposited and patterned to form patches between the resonators. Microwave tests of the filter with and without the BaTiO₃ patches were performed at low temperatures. The filter has measured center frequency of 1.65 GHz with a bandwidth of 20 MHz. The results show the effect of using BaTiO₃ patches on top of YBa₂Cu₃O₇. The most current results on the performance of the filter will be presented.