基于模拟预失真的高效率功率放大器的设计与实现

发布时间：2018-04-06 22:16

本文选题：射频功率放大器　切入点：Doherty功放　出处：《北京邮电大学》2015年硕士论文

【摘要】：随着科学技术的快速发展,无线带宽异常紧张现象日益严重,促使现代无线通信系统基站子系统朝着高带宽、快速率、高效率方向发展,而在无线通信系统基站子系统中,射频功率放大器作为发射机的末端,它的功能主要是将直流功率转换为射频发射信号,因此射频功率放大器是整个系统最大的耗能器件,在很大程度上决定了基站的耗电量、输出功率的大小以及发射机整体的线性度。本文以提高功放效率和功放线性度为目的,分别对Doherty技术和线性化技术进行了研究与分析。本文采用经典两级Doherty结构来提高功放效率,预失真技术提升功放线性度。 Doherty功放的设计采用了飞思卡尔(Freescale)公司的MRF6V3090N芯片,主要工作如下： (1)对Doherty放大器理论进行了分析研究,同时对设计时的注意要点,特别是阻抗变换和Offset-line微带线理论做出了重点分析。 (2)根据有源负载牵引理论,主要设计了一款中心频率为400MHz,工作带宽为30MHz,功率回退-6dB时工作效率不低于40%的Doherty功率放大器。模拟预失真器的设计采用了Scintera公司的SC1894芯片,根据芯片手册搭建外围电路。由于需要将功放输出功率耦合一部分信号出来反馈给SC1894,以使模拟预失真器达到最佳性能,提高功放的线性度。其中耦合器为平行微带耦合器。
[Abstract]:With the rapid development of science and technology, the phenomenon of abnormal shortage of wireless bandwidth is becoming more and more serious, which makes the base station subsystem of modern wireless communication system develop towards the direction of high bandwidth, fast rate and high efficiency, while in the base station subsystem of wireless communication system,As the end of transmitter, the function of RF power amplifier is mainly to convert DC power into RF transmitting signal, so RF power amplifier is the biggest energy dissipation device in the whole system, which determines the power consumption of base station to a great extent.The output power and the overall linearity of the transmitter.In order to improve the efficiency and linearity of power amplifier, Doherty and linearization techniques are studied and analyzed respectively in this paper.In this paper, the classical two-stage Doherty structure is used to improve the efficiency of power amplifier, and the predistortion technique is used to improve the linearity of the amplifier.The design of Doherty power amplifier adopts the MRF6V3090N chip of Freescale of Freescale, the main work is as follows:1) the theory of Doherty amplifier is analyzed, and the key points of design, especially impedance transform and Offset-line microstrip line theory, are analyzed.The analog predistorter is designed with Scintera SC1894 chip, and the peripheral circuit is built according to the chip manual.Due to the need to feedback a part of the output power coupling signal to SC1894, the analog predistorter can achieve the optimal performance and improve the linearity of the amplifier.The coupler is a parallel microstrip coupler.
【学位授予单位】：北京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722.75

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