Cryogenic noise parameter measurements of microwave devices

A robust measurement technique, the seven-state-method, which is well suited for noise parameter measurements at cryogenic temperatures is presented. The optimum generator admittance Y/sub opt /and the input admittance Y/sub in/ of the device under test are calculable from noise power measurements with a noise source operated at ambient temperature. Therefore the measurement of Y/sub in/ with a network analyser as needed for other techniques is not necessary.