Hybrid Envelope Elimination and Restoration Technique for Enhancing the Linearity of Switchmode Envelope Amplifiers

This letter shows a new technique for enhancing the linearity of switchmode envelope amplifiers used in Envelope Elimination and Restoration (EER) amplifiers. The proposed solution increases the linearity of EER amplifiers using switchmode converters as envelope amplifiers avoiding additional hardware for compensating their inherent distortion at low output voltage levels. This technique combines hybrid EER (H-EER) and drive modulation techniques applied to a radio frequency (RF) amplifier operating in mixed mode. It is illustrated by means of an L-Band suboptimum Class-E power amplifier using GaN HEMTs linearized by a multi-phase switchmode envelope amplifier.