Low Power Superconducting Microwave Applications and Microwave Microscopy

We briefly review some non-accelerator high-frequency applications of superconductors. These include the use of high-T c superconductors in front-end band-pass filters in cellular telephone base stations, the High Temperature Superconductor Space Experiment, and high-speed digital electronics. We also present an overview of our work on a novel form of near-field scanning microscopy at microwave frequencies. This form of microscopy can be used to investigate the microwave properties of metals and dielectrics on length scales as small as 1 μ m. With this microscope we have demonstrated quantitative imaging of sheet resistance and topography at microwave frequencies. An examination of the local microwave response of the surface of a heattreated bulk Nb sample is also presented. I. Introduction The discovery of high temperature superconductivity in 1986 created the hope of finding many new applications for superconductors in the everyday world.[1] In this paper we discuss several applications which make use of the unique high frequency properties of superconductors. We also present an overview of our recent work on nea r-field microwave microscopy, and how these instruments can have an impact on superconducting microwave technology.