Quasi Pinch-Off GaAs FET Linearizer for Microwave SSPAs

A new microwave linearizer is hereafter presented. The linearization exploits the principle that in a GaAs FET device biased near the pinch-off region the drain current and the power gain grow when the input power increases (AM/AM compensation). At the same time, placing a bias resistance on the drain, the variation of the drain voltage may be used to drive a varactor phase-shifter achieving a compensation for the AM/PM distortion. By taking due advantages of the MIC and MMIC technology the linearizer may be easily built and inserted in the SSPA line-up with high performance, compactness and low cost.