Design and Performance of Superconducting Bulk Coil for RF Applications

We have designed the first superconducting bulk coil for radio frequency (RF) applications. We investigated the effect of the line gap and line width of the coil by simulating the quality factor of the coil for each gap and width. We investigated several supporting dielectric materials and identified one that negligibly affects the quality factor and thus maintains the coil configuration. To investigate the potential for obtaining a high quality factor for the superconducting bulk coil, we measured a frequency response and quality factor of a test sample of superconducting bulk coil with an unoptimized line gap and line width. Despite the non-optimized structure, the quality factor of the coil was three times that of a copper coil. Since there have been no reports on the conductivity of superconducting bulk in the MHz range, we determined an effective conductivity on basis of the measured quality factor. When the superconducting bulk coil was redesigned on the basis of the assumed effective conductivity, the simulated quality factor of an optimized superconducting bulk coil was 19 times that of a copper coil.