Dielectric property measurement system at cryogenic temperature and microwave frequencies

A system based on the resonant cavity method has been developed to measure the permittivity and loss tangent at 12-18 GHz over the temperature range 80-300 K. Changes of permittivity as low as 0.01% in the range 1-30, 3x10/sup -6/ for loss tangent values below 10/sup -2/, can be measured without requiring temperature stability. The thermal expansion coefficient and resistivity factor of copper have been measured between 80 K and 300 K. The permittivity of sapphire and loss tangent of alumina of 99.9% purity in the same temperature range are presented.<
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