A cryogenic PAF system with hundreds of LNAs requires a test system that can measure many LNAs simultaneously. An existing test system will be presented, with which the S-parameters of six temperature cycled LNAs can be measured automatically over a long timescale. As part of a partnership with the IAF, a project has been started to develop cryogenic LNAs - called "Cryo mHEMT Project". Results of completed LNA designs and measurements will be presented. Within the Cryo mHEMT Project a on-wafer prober station was developed at the MPIfR to enable large volume semi-automated cryogenic measurement of noise and S-parameters at cryogenic temperatures. The developed system is capable of characterizing several 100 MMICs and Transistors on-wafer during a single cooling cycle at a temperature of ~12K. The setup of the system and the procedure of the MMIC measurements with the on-wafer prober will be shown.