Processing and microwave electrical properties of high-temperature superconductors

High-temperature superconductors exhibit finite resistance in alternating electromagnetic fields. Bulk processing techniques have been used to form high-temperature-superconducting materials into large and complex shapes and are particularly useful for resonant cavities and antenna elements. The surface resistance (R/sub s/) of polycrystalline YBCO (Y-Ba-Cu-O) was found to be significantly lower than that of copper below 1 GHz; however, degradation occurs with increasing magnetic field. Potential applications are discussed in terms of the electrical properties and the ability to fabricate materials into useful shapes.<>