Frequency Dependence Measurements of Surface Resistance of Superconductors Using Four Modes in a Sapphire Rod Resonator

Toru HASHIMOTO  Yoshio KOBAYASHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.8   pp.1721-1728
Publication Date: 2003/08/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter Wave Technology)
Category: 
Keyword: 
high-Tc superconductors,  microwave,  surface resistance,  frequency dependence,  

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Summary: 
The frequency dependence of surface resistance Rs of high temperature superconductor (HTS) films are measured by a novel measurement method using four TE0mp modes in a sapphire rod resonator. At first, a loss tangent tan δ of the sapphire rod and Rs of the HTS films are evaluated separately from the results measured for the TE021 and TE012 modes with close resonant frequencies. Secondly, Rs values at two different resonant frequencies for the TE011 and TE022 modes are measured using a well-known relation for sapphire tan δ/f = constant, where f is a frequency. Rs values of HoBa2Cu3O7-x thin films were measured in the frequency range of 10 to 43 GHz by using four sapphire rod resonators with different sizes. As a result, it is found that these measured results of Rs have a characteristic of frequency square.