随着无线通信系统的发展,人们对数据和信息的需求在不断的增加。功率放大器作为通信系统中最重要的模块之一,功放的性能对整个系统性能的影响至关重要。面对高速增长的移动数据业务和频谱资源短缺的威胁,高峰均比(PAR)的调制方式不断出现,如OFDM调制方式,这就对功放的线性度提出了较高的要求。为了保证信号的线性度,一般采用功率回退的方法来实现。以NXP公司的140W晶体管为模型,在ADS仿真软件中设计对称Doherty仿真电路。设计完成的功放电路能够在6dB功率范围内保持高效率工作。
With the development of wireless communication systems,the demand for data and information is increased.Power amplifier as one of the most important modules whose performance is essential for the overall system.To overcome the threat of rapid growth of mobile data and services and the shortage of spectrum resources,and for the appearance of modulation modes of high PAR such as OFDM modulation,for which a high requirement on the linearity of PA is put forward.In order to ensure signal linearity,the power back off method is generally used.Doherty technology can make the amplifier maintain high efficiency in a wide rang of power output.