Outphasing Methods for Beyond-5G Millimeter-Wave Base Station Applications

This paper presents a review of various outphasing methods. Key performance indicators are formulated focusing on reliability, energy consumption and bandwidth and are used to compare state-of-the-art outphasing methods. Outphasing methods which show potential for beyond-5G base station applications are described and relevant advantages, disadvantages and literature gaps are pointed out. Specifically, the recent developments on using antenna elements to be co-designed with an outphasing system will be considered as a promising efficient solution. Findings in this paper show that a co-designed amplifier-antenna outphasing system achieves one of the highest peak power-added efficiencies at millimeter-wave frequencies compared to other PA topologies.