Efficiency and linearity enhancements with envelope shaping control in wideband envelope tracking GaAs PA

Memory models for behavioral modeling and digital predistortion of envelope tracking power amplifiers

“…An ET PA can be operated with a number of nuances in its operational mode according to the wanted trade-off between the overall optimization of transmitter efficiency and linearity. For example, an ET transmitter typically deploys a supply shaper which can be designed to improve system linearity, efficiency or a combination of them [14,15]. Each shaper can produce a different version of the envelope and operate the PA in different conditions that can affect its system level parameters.…”

Envelope tracking RF power amplifier with lead-lag modulator

“…DPD is often used to compensate for the RF PA's gain dependency on its supply voltage [8]. An envelope signal is generated and applied to the LA.…”

“…The remaining high frequency content is amplified by the LA, which often operates in the 20-30% efficiency area. Applying envelope shaping (ES) [8] can increase the low frequency content to 90%, therefore reducing the impact of a low LA efficiency. ES also prevents the envelope voltage from fully tracking the modulated RF carrier into the nulls.…”

A low-complexity memoryless model for envelope tracking RF power amplifiers

“…1. The baseband signal to be amplified is R x , the real envelope of R x is E and this is modified by an envelope shaping function [5] [6] in order to obtain S E . The supply signal S E is amplified by the envelope amplifier (EA) and then the resulting D E is used to feed the RF PA (usually a class A or AB topology).…”