Study of RF-circuit linearity performance of GaN HEMT technology using the MVSG compact device model

Abstract

This study is a first demonstration of the use of a physical compact model as a tool to identify technology bottlenecks to the linearity performance of emerging devices such as GaN HEMTs and to provide solutions to improve linearity both through device-design and circuit-design techniques. GaN-based HEMTs are emerging as key technology solutions in wireless communication systems that can address the increasing demand for highly efficient, linear amplification of digitally modulated information to cater to new applications such as personal communication, internet of things, 5G etc [1]. The primary advantage of GaN-HEMTs in terms of higher bandgap, carrier-mobility and charge-density can yield better output power (Pout), and power-added-efficiency (PAE) but the linearity behavior of GaN-based power amplifiers (PAs) that trades-off with the aforementioned figures of merit (FoMs) is still to be understood. Non-linearity results in adjacent channel interference, spectral regrowth, and degrading error vector magnitude (EVM) that impose bandwidth constraints and higher bit error rate (BER) for complex modulated signals.