Compact superconducting dual-log spiral resonator with high Q-factor and low power dependence

Hejazi, Z M and Excell, Peter S (2002) Compact superconducting dual-log spiral resonator with high Q-factor and low power dependence.


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A new dual-log spiral geometry is proposed for microstrip resonators, offering substantial advantages in performance and size reduction at subgigahertz frequencies when realized in superconducting materials. The spiral is logarithmic in line spacing and width such that the width of the spiral line increases smoothly with the increase of the current density, reaching its maximum where the current density is maximum (in its center for 2 resonators). Preliminary results of such a logarithmic ten-turn (2 5 turns) spiral, realized with double-sided YBCO thin film, showed a -factor seven times higher than that of a single ten-turn uniform spiral made of YBCO thin film and 64 times higher than a copper counterpart. The insertion loss of the YBCO dual log-spiral has a high degree of independence of the input power in comparison with a uniform Archimedian spiral, increasing by only 2.5% for a 30-dBm increase of the input power, compared with nearly 31% for the uniform spiral. A simple approximate method, developed for prediction of the resonant frequency of the new resonators, shows a good agreement with the test results.

Item Type: Article
Additional Information: Copyright © 2002 IEEE. Reprinted from the published proceedings of the IEEE Transactions on Applied Superconductivity, in June 2002.This material is posted here with permission of the IEEE and the author. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the products or services of Glyndwr University Wrexham. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to choosing to view this document, you agree to all provisions of the copyright laws protecting it.The definitive version is available at
Keywords: HTS microwave devices, HTS resonators, logarithmic spiral, spiral inductors, YBCO thin films.
Divisions: ?? GlyndwrUniversity ??
Depositing User: ULCC Admin
Date Deposited: 05 Oct 2011 09:14
Last Modified: 11 Dec 2017 20:06

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