A Digital Envelope Combiner for Switching Power Amplifier Linearization

A digital envelope combiner (DEC) technique that employs an open-loop transformer-based combination of a bank of two-level polar switching power amplifiers to generate wide-bandwidth modulated radio frequency signals with simultaneously high efficiency and good linearity is presented. The application of the DEC is illustrated by the design and simulation-based verification of a 2.4-GHz 0.13-¿m complementary metal-oxide-semiconductor power amplifier that achieves EVM < -25 dBc, ACPR < -40 dBc, and an average drain efficiency of 37% while generating a 16.25-MHz-bandwidth 8.9-dB-peak-to-average signal power ratio (PAR) 64-state quadrature amplitude modulation signal.