On Wafer Automatic Three Ports Measurement System for MMIC Circuits and Dual Gate FETs

Recent advances in monolithic design point out the need for accurate and repeatible "S" parameters measurements of three ports RF circuits such as dual gate FETs. This paper presents an automatic on wafer three ports system for frequencies up to 26.5 GHz consisting of a two ports Network Analyser and wafer probes, that is used to provide RF measurements of three ports devices and to extract the model of dual gate FETs. On wafer calibration method including the open short load and transmission technique with on GaAs standards is used, probe techniques for making the best possible on wafer measurements and a range of measurement applications are examined.