Efficiency and linearity enhancements with envelope shaping control in dual-band envelope tracking GaAs PA

In this paper we present the efficiency and linearity trade-off of a dual band power amplifier (PA) for envelope tracking (ET) operation. The paper discusses the impact of envelope shaping i.e. the mapping of the drain modulated waveform to the RF output power, on system linearity and efficiency performance, for a given signal statistic. The technique was applied to a dual-band ET PA designed around a GaAs HEMT at 940 and 1940 MHz. Analytical treatment of the design technique along with characterization at device and system level are also presented in the paper.