High temperature superconductor films and devices for the microwave communication industry

High temperature superconductor (HTS) thin films can be used to construct microwave devices such as filters and antennas with superior performance. We show how the films can be manufactured using a sol–gel method which has the advantage of being able to produce large area films quickly, at low cost on simple equipment. We have developed a sol–gel precursor which has the additional benefits of using commonly available non-toxic reagents, and which can be prepared quickly. High Tc and high Jc films have been made with this precursor. These films can be patterned to make microwave filters with better sensitivity and selectivity than conventional filters. A design for a microstrip layout of a quasi-elliptic bandpass filter which can be implemented on a 10 mm × 10 mm film is described. Simulated results comparing filter implementations with metal and superconductor films operating at 77 K are given.