Design, Construction, and Performance Evaluation of a Cryogenic 7-mm Coaxial Noise Standard

摘要

A cryogenic 7-mm coaxial noise standard at 77.35 K has been designed and constructed. A ferrite composite-matched termination was used as a thermal noise source in the frequency range of 4.5–18 GHz. The noise temperature of the noise standard has been determined by measuring the temperature distribution and attenuation constant of a thermally isolated coaxial line and the attenuation of the output connector. The effective noise temperature has been evaluated to be 84.07–92.21 K with an uncertainty of 1.26–1.67 K $(k = 2)$.