Power Amplifier Linearization and Efficiency Improvement Techniques for Commercial and Military Applications

This paper presents some recent developments in the area of power amplifier (PA) linearization and efficiency improvement techniques. Advanced digital pre-distortion (DPD) architectures implemented with digital signal processing (DSP) are discussed. Various results of improvements in intermodulation distortion (IMD) when applied to high power RF amplifiers are presented. Crest factor reduction (CFR) has been shown to substantially increase the power output, and hence the efficiency of PAs operating with high peak-to-average waveforms. The combination of DPD and CFR is shown to improve both efficiency and linearity to levels previously unachievable with analog technologies alone for commercial wireless applications. Independent of these signal processing techniques, polar transmitter circuit architectures have been proposed to improve PA efficiency. A combination of a polar transmitter architecture operating in combination with DPD and CFR is proposed in this paper to address more demanding military wireless communications applications.