Progress, properties and prospects of passive high-temperature superconductive microwave devices in Europe

The technology of high-temperature superconductors has become mature. Various methods to analyse and optimize the temperature and microwave field dependent surface impedance have been developed. Promising applications of passive microwave devices have been identified between 0.01 and 10 GHz. This progress profits from improved design and simulation tools, aimed at miniaturizing the circuits at optimum performance and integrating them into realistic systems. Important facets of these developments are sketched in terms of their physical basis and illustrated with selected examples of filters, stable oscillators and MRI antennas.