A waveform engineered power amplifier design for envelope tracking

摘要

A novel load network design for limited harmonic manipulations to implement a transmission line waveform engineered radio frequency power amplifier for LTE applications is presented in this paper, with the target to achieve quasi-linear efficiency during power back-offs with harmonic iteration. The topology selection was based on accurate large signal modeling and simulation to obtain optimum microstrip line design controlling the 2nd and 3rd order harmonics at the transistor output terminal. The design was implemented using the Cree CGH40010F GaN HEMT at 2.14GHz. It provides a continuous wave (CW) drain efficiency of 73.7% at a saturated output power of 40.7dBm at a fixed 30V supply, but it was optimized for linearization with LTE 64QAM 20MHz modulated signal with a power-added efficiency (PAE) of 42.7% at an average output power of 34.9dBm with linearity meeting 3GPP specifications, as well as envelope tracking with almost 70% power added efficiency from the same PA.