Investiogation of linearity improvement with dynamic gate bias technique for flat gain or phase of an 10 W GaN HEMT power amplifier

Abstract

Possibility of linearity improvement using a dynamic gate biasing technique for flattening a gain or a phase of a 10 W GaN HEMT PA has been investigated. It is shown that a polynomial gate tracking function of acceptable order can be used for that purpose. Linearity improvement while maintaining efficiency by flattening the phase transfer of the PA with dynamic gate bias technique has been shown in a simulation. Results are showing 5 dB better ACPR compared to a reference static bias PA. Flattening the gain of the PA does not result in any linearity improvement due to a large phase transfer change of the PA caused by dynamic gate bias.