Microwave application of high temperature superconductors

Since the discovery of a group of ceramic materials that become superconducting at liquid nitrogen temperatures, the development of materials. components and subsystems that exploit the low dissipative losses has progressed steadily to the point where they are no longer a laboratory curiosity but have become practical devices offering significant performance benefits. This review article outlines the work performed within the Marconi Research Centre on the development of RF components and subsystems that use these high temperature superconductors. A range of high performance components has been developed, including filters, oscillators and delay lines, Some of those have been integrated into subsystems, along with circuits using conventional conductors and semiconductors, to form switched filter banks. passive filter combiner; and frequency resolving multiplexors. The enabling and supporting technologies such as cryo-packaging and cooling have matured and commercial exploitation is emerging. Developments for military applications offering enhanced performance to radar and EW systems have reached an advanced stage. Similar commercial subsystems for telecommunications have been manufactured.