Direct design of Doherty and Chireix PAs using a nonlinear embedding device model

Abstract

Waveform engineering is commonly used to optimize the power efficiency, linearity and output power of power amplifiers (PA). In this search for the optimal waveforms, PA designers have become interested in knowing the internal mode of operation of the device at the current-source reference-planes. However given the huge search space for the input and output multi-harmonic terminations required to find the desired internal waveforms, it is much desirable to use a nonlinear embedding device model to readily obtain the required multi-harmonic voltage and current waveforms at the transistor measurement (package or extrinsic) reference-planes in order to realize the desired mode of operation at the current-source reference-planes. In this paper, examples of such designs for Doherty, Chireix and class-J amplifiers will be presented to demonstrate how this promising technique streamlines the design of such PAs.