Cryogenic Noise Parameter Measurements of Microwave Devices

Ilona Rolfes, Thomas Musch, Burkhard Schiek

IEEE Transactions on Instrumentation and Measurement, Vol. 50, No. 2, pp. 373-376, April 2001


A robust measurement technique, the seven-state method, which is well suited to noise parameter measurements at cryogenic temperatures is presented. In contrast to existing concepts, the seven-state method makes it possible to determine the minimum noise figure Fmin and the equivalent noise resistance Rn except for a constant term m with the help of noise power measurements with a noise source operated at ambient temperature only. The optimum generator admittance Y opt and the input admittance Yin of the device under test are completely calculable from cold noise power measurements. An additional measurement of Yin with a network analyser as needed for other techniques is not necessary. In order to determine the unknown factor m, one further noise power measurement with a hot noise source has to be performed. A measurement system as well as measurements which were performed on AlGaAs/InGaAs HEMT transistors at ambient and cryogenic temperatures are presented

[IEEE Library]

Tags: cryogenic temperatures, Noise