A Narrow-Band Superconducting Filter Using Spirals with a Reversal in Winding Direction

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A resonator consisting of a microstrip spiral, with a reversal in winding direction, is used for a narrowband superconducting filter. The fields are tightly confined, leading to the required small coupling coefficients, without a large separation between resonators. Nevertheless, tunability and power-handling capacity are better than some other resonators with localized fields. A quality factor exceeding a million was achieved. A 148 MHz, 0.1% bandwidth sixth-order quasi-elliptic filter is demonstrated.


Original languageEnglish
Pages (from-to)3954-3959
Number of pages6
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number11
Publication statusPublished - 1 Nov 2006


  • narrowhand, spiral, superconducting, filters