Multispectrum Signal Transmitters: Advances in Broadband High-Efficiency Power Amplifiers for Carrier Aggregated Signals

This article described recent advances in Doherty power amplifiers (DPAs) with extended bandwidth for use in future radio transmitters intended to support carrier aggregation signal transmission. It provided a review of several configurations of two-way (using symmetrical and asymmetrical drain supply voltages) and three-way DPAs. Furthermore, it identified various approaches to ensure proper load modulation over extended bandwidth by incorporating novel combining networks. It also discussed the additional challenges associated with the linearizability of DPAs when driven with interband aggregated signals.