A Review of PA-Antenna Co-design: Direct Matching, Harmonic Tuning and Power Combining

This article reviews the current state-of-the-art of active-integrated antennas co-designed with power amplifiers (PAs). Three strategies to improve output power and power-added efficiency are described using examples, namely direct matching between PA and antenna, tuning of harmonic reflections in the antenna, and in antenna power combining from multiple PAs. An outlook is given on the challenges to be faced in the application of these strategies in wide-scanning phased arrays