A High-Efficiency Transmission-Line GaN HEMT Class E Power Amplifier

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  • Author: Andrei Grebennikov
In modern wireless communication systems it is required that the power amplifier could operate with high efficiency, high linearity, and low harmonic output level simultaneously. To increase efficiency of the power amplifier, a switching-mode Class E mode technique can be applied. This kind of a power amplifier requires an operation in saturation mode resulting in a poor linearity, and therefore is not suitable to directly replace linear power amplifiers in conventional WCDMA or CDMA2000 transmitters with non-constant envelope signal. However, to obtain both high efficiency and good linearity, a nonlinear highefficiency power amplifier operating in a Class E mode can be used in advanced transmitter architectures such as Doherty, LINC (linear amplification using nonlinear components), or ET (envelope tracking) with digital predistortion. In this paper, a novel transmissionline load network for a Class-E power amplifer with simple design equations to define its load-network parameters is presented.