A Review of Memory Effects in AlGaN/GaN HEMT Based RF PAs

This work is an overview of the current understanding of memory effects arising from AlGaN/GaN HEMT based RF power amplifiers. It reviews the most widely accepted physical sources of those memory effects and their impact on the amplifier's linearizability, to then discuss corresponding circuit design approaches to minimize the phenomena. This is illustrated by results of a power amplifier whose short-term and long-term nonlinear memory is compensated by an analog assisted digital pre-distortion scheme.