Perspectives of superconducting MgB2 for microwave applications
  We discuss the temperature, frequency, and power-dependent surface resistance of the boride superconductor MgB2 in relation to possible applications for passive microwave devices. The data available in the literature are compared with results for polycrystalline Nb3Sn and epitaxial YBa2Cu3O7-x, which are representative of the classical and cuprate superconductors. MgB2 displays all specific features that make superconductors attractive for high-performance devices, even though the fabrication technology is not yet mature. We attempt to identify promising areas of applications, as well as material requirements, which could further promote the attractiveness of the new superconductor in this field. 
Matthias A. Hein