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

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> 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 <formula formulatype="inline"><tex>$(k = 2)$</tex></formula>. </para>