J. Molla et al., DIELECTRIC PROPERTY MEASUREMENT SYSTEM AT CRYOGENIC TEMPERATURES AND MICROWAVE-FREQUENCIES, IEEE transactions on instrumentation and measurement, 42(4), 1993, pp. 817-821
A system based on the resonant cavity method has been developed to mea
sure the permittivity and loss tangent at 12-18 GHz over the temperatu
re range 80 K-300 K. Changes of permittivity as low as 0.01% in the ra
nge 1-30, 3 X 10(-6) for loss tangent values below 10(-2), can be meas
ured without requiring temperature stability. The thermal expansion co
efficient and resistivity factor of copper have been measured between
80 K and 300 K. The permittivity of sapphire and loss tangent of alumi
na of 99.9% purity in the same temperature range are presented.