Efficiency First: Outphasing Architectures for Power Amplification of High-PAPR Signals

``Efficiency first´´ approaches to linear-efficient microwave power amplification can be generalized as ones employing nonlinear but efficient amplifier classes in architectures that produce linear output control. Within this strategy, outphasing architectures can be particularly successful due to the wide operating range over which all branch PAs remain in saturation. Despite this potential, outphasing has historically seen limited success due to limitations of its conventional implementations. This work gives an overview of outphasing techniques and describes recently developed techniques addressing the drawbacks of conventional implementations.