为了满足日益增长的移动通信流量需求，5G网络一方面应用多种宽带通信技术增加调制信号的带宽，另一方面应用Massive MIMO技术探索信道在空间的复用。信号带宽的不断增加要求功率放大器支持宽带多信道传输，而Massive MIMO技术则要求发射机中使用多路放大器，这些新的需求急剧增加了应用数字预失真技术进行功放线性化时的附加成本和功耗。针对这些问题，本项目拟研发新的负载调制型放大器技术，在不牺牲效率的前提下，提升放大器在传输宽带、多通带调制信号的线性度，去除发射机系统对于高成本数字预失真技术的依赖。通过分析国内外最新的研究成果并基于申请人在功放设计领域的研究成果，本项目将探索负载调制型功放在回退区的非线性特性的产生机制和主要来源，在此基础之上，研发可用于放大器后端的非线性失真的补偿网络，并进一步研发能够拓展该补偿网络工作带宽的谐波波形控制技术，最终完成对放大器的带宽和线性度等关键指标的提升

Driven by the ever-increasing demand in mobile data throughput, the 5th generation mobile communication system adopts wideband modulated signal formats as well as exploiting space multiplexing by using the Massive MIMO technique. While the increase in signal bandwidth demands the power amplifier (PA) to support broadband and multiband transmission, the Massive MIMO technique demands a new transmitter architecture where a large scale array of PAs are employed in parallel to driven an antenna array with the same size. These new applications of PA significantly increase the cost and power consumption associated with linearization if using digital pre-distortion techniques to sample and linearize each PA element in the Massive MIMO transmitter. Concerning this problem, this proposal aims at investigating a new load-modulated PA technique to improve the PA linearity under wideband communication signals without sacrificing its efficiency. Ultimately, this helps with eliminating the needs of the expensive digital pre-distortion technique. Based on the newest domestic and international research outcomes as well as the related high-performance PA researches done by the applicant, the proposal will investigate and analyze mechanisms that generate nonlinearities in the power back-off region of the high efficiency load-modulated PA. These analyses then guide the development of new linearization methods that utilize the nonlinearity of a deliberately designed combiner network to compensate for the main PA nonlinearity, consequently improving the linearity of the overall PA. Furthermore, we also target developing new waveform engineering techniques that helps to expand the bandwidth over which the enhanced linearity can be maintained. The application of these new techniques, together with the novel linearization methods, ultimately produces wideband and high linearity load-modulated amplifier designs that help to knock down the cost, complexity and power consumption of 5G Massive MIMO transmitter.