Microwave applications of high-temperature superconductors

For at least eight of the first ten years of high-temperature superconductivity it has been clear that one of the earliest areas of application and commercialization of these materials is as passive devices for microwave electronics. At the time of writing the first prototype products are entering service in the mobile communications industry and a wide range of other devices are at a relatively advanced stage of development. In the further future one can see a cryogenic integrated technology based on HTS materials and the related functional materials which have emerged within the last ten years.