Virginia TechNamboodri, S. L.Davis, William A.Kander, R. G.2014-04-092014-04-091994-04-01Namboodri, 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/10.1063/1.11451030034-6748http://hdl.handle.net/10919/47059A 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.application/pdfenIn CopyrightCopperHigh temperature superconductorsMicrowavesPolymer waveguidesElastomeric polymersMicrowave spectroscopySuperconductorsArticle - Refereedhttp://scitation.aip.org/content/aip/journal/rsi/65/4/10.1063/1.1145103https://doi.org/10.1063/1.1145103