Progress in Superconductivity

한국초전도학회 (The Korean Superconductivity Society)
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Two-Resonance Mode 방법용으로 제작된 고온초전도 평행판 사파이어 공진기의 마이크로파 특성

Microwave Properties of HTS Parallel-Plate Sapphire Resonators Designed for the Two-Resonance Mode Method

  • Jung, Ho-Sang (Department of Physics and Center for Wireless Transmission Technology, Konkuk University) ;
  • Yang, W.I. (Department of Physics and Center for Wireless Transmission Technology, Konkuk University) ;
  • Lee, J.H. (SuNAM Co., Ltd) ;
  • Lee, Sang-Young (Department of Physics and Center for Wireless Transmission Technology, Konkuk University)
  • 투고 : 2010.03.08
  • 심사 : 2010.04.14
  • 발행 : 2010.04.30
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초록

Sapphire resonators with $YBa_2Cu_3O_{7-\delta}$ (YBCO) endplates have provided a way to realize extremely high quality factor due to the extremely low dielectric loss of sapphire and conductive loss of YBCO films, which enables to measure the low surface resistance of superconductor films at microwave frequencies. We present microwave properties of HTS sapphire resonators designed for measuring the surface resistance of HTS films at millimeter-wave frequencies by using the two-resonance mode dielectric resonator method. Despite enhanced surface resistance ($R_S$) of YBCO films due to the quadratic frequency dependence of the $R_S$, the unloaded quality factor ($Q_0$) of the $TE_{021}$ mode sapphire resonator still appears to be well above $1\;{\times}\;10^6$ at a mm-wave frequency of 38 GHz at 10 K. However, it appears that the $TE_{012}$ mode $Q_0$ is unexpectedly low despite that the corresponding resonance peak looks uncoupled with parasitic modes. We discuss possible reasons for the unexpected results using the surface resistance at the $TE_{021}$, $TE_{012}$, and $TE_{011}$ mode frequencies.

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참고문헌

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