Power supply modulation for RF applications

Envelope tracking is a promising means to enhance radio frequency power amplifier efficiency for signals with non-constant envelope. The adaption of the power amplifier supply voltage is performed by a voltage modulator circuit, which is mainly based upon power electronics circuits, but requires bandwidths up to the MHz region. This paper introduces the benefits and challenges of envelope tracking and gives an overview of several voltage modulator architectures. Current measurement data of a class-G modulator is presented as well.