MICROWAVE APPLICATIONS OF HIGH-TEMPERATURE SUPERCONDUCTORS

The major advance in the area of high temperature superconducting micr owave devices has been in the incorporation of high performance device s (based on planar transmission line structures or shielded dielectric resonators) into microwave receiver systems with performances equival ent or better than those of conventional systems. These systems includ e reliable closed-cycle coolers that can allow access to the low tempe ratures required for efficient operation (< 80K). Nonlinear effects at high powers have previously presented a drawback for these novel devi ces, but superconducting thin film disc resonators, operating in modes with radial current flow (in addition to compact, shielded dielectric resonators), do not suffer from the very high microwave edge current densities present in planar structures, and have demonstrated very enc ouraging microwave power handling capabilities.