Measuring Microwave Shielding Effectiveness in Liquid-Nitrogen

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TR Number
Date
1994-04-01
Journal Title
Journal ISSN
Volume Title
Publisher
AIP Publishing
Abstract

A technique to distinguish between materials that can and cannot shield microwaves in liquid nitrogen was developed. The samples are placed in a modified X-band waveguide, which operates by the same ''insertion loss'' principle as a coaxial device used to measure shielding effectiveness from 300 to 1000 MHz. Verification of the waveguide fixture was accomplished by measuring the shielding effectiveness of a good conductor, coppper; a nonconductor, Teflon; and two intermediate conductors, steel and a carbon-filled elastomer. After verification, the waveguide fixture was used at liquid nitrogen temperatures to compare the shielding effectiveness of YBa2Cu3O7-x, a high temperature superconductor, with copper, a known shielding material.

Description
Keywords
Copper, High temperature superconductors, Microwaves, Polymer waveguides, Elastomeric polymers, Microwave spectroscopy, Superconductors
Citation
Namboodri, S. L.; Davis, W. A.; Kander, R. G., "measuring microwave shielding effectiveness in liquid-nitrogen," Rev. Sci. Instrum. 65, 1002 (1994); http://dx.doi.org/10.1063/1.1145103