Guest Editorial

The article in this special section provide a mix of practical and theoretical papers on the topic of power amplifiers (PAs) from radio frequency to millimeter-wave frequencies. Researchers present improvements to standard PAs and innovative PA systems that improve the efficiency using dynamic supply modulation, load modulation in the form of Doherty configured PAs, and outphasing PAs. A few of the papers examine intrinsic improvements in behavioral modeling and DPD, others address behavioral model issues associated with changes in impedance match (from antenna mismatch) or signals. Some of the signal changes are intentional, such as non-contiguous signals (on multiband PAs), or harmonic signal interference.