Analytical method for deriving consistent large-small-signal field-effect transistor model

Abstract

This article presents a detailed analytical method for deriving consistent large–small-signal field-effect transistor (FET) model. This resulted in a set of closed-form equations relating the large-signal model parameters to the small-signal model ones. An improved equivalent circuit is proposed for modeling the transistor under large-signal operation. In this circuit, RF nonlinear current sources are used to model the distributed effect of the gate–source and gate–drain junctions. The dispersion between DC and RF drain current characteristics is modeled using an improved back-gating technique. The predictive model capabilities are illustrated with measured and simulated S-parameters, output power at fundamental and harmonics frequencies of a commercial packaged GaAs FET device. The model is then fully validated by comparing measured and simulated results of output power, efficiency, and intermodulation distortion of a class AB amplifier designed at 1.9 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1001–1008, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27495