基于包络跟踪的LTE基站功放研究

发布时间：2018-02-02 22:39

  本文关键词： 包络跟踪 Doherty 线性度 效率　出处：《电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：LTE通信系统的下行信号是具有高峰均比的多载波信号,这种信号对基站功率放大器的线性度提出了更高的要求。同时,出于对环保节能的需要,基站功放也必须达到高效率的要求。基于上述的应用要求,本文研究了将包络跟踪技术应用到Doherty功率放大器中,以达到在保证基站功放高效率的同时,提升系统高功率输入状态下的线性度。本文的主要工作是在对Doherty放大器的研究基础上,提出利用包络跟踪信号控制Doherty放大器中峰值功放栅极电压的方法。通过这种方法,实现在小功率输入时降低栅压以获得高效率;在大功率输入时提升栅压,在牺牲小部分效率的情况下提升线性度。本文的研究主要包括:1.对功率放大器基本理论进行了研究,并分析了Doherty放大器的基本原理。2.对包络跟踪技术进行分析和研究,并对当前主流的包络跟踪电路结构进行了系统的总结。3.详细分析、研究了包络跟踪技术对Doherty放大器的电路性能的影响,并给出了分别控制载波、峰值功放栅压和漏压的结果比较。在此基础上,针对2.59GHz的LTE系统,提出了一种利用包络跟踪控制峰值功放栅压的电路结构,以改善Doherty放大器的线性性能。4.对包络跟踪的Doherty放大器进行了设计和制作,并在实验室条件下进行了测试。测试结果显示,在功率回退8d B内,包络跟踪的Doherty放大器相对于传统的Doherty放大器,三阶互调改善了约3~5d Bc,而效率仅恶化了2~4%左右。
[Abstract]:The downlink signal of LTE communication system is a multi-carrier signal with peak-to-average ratio, which requires higher linearity of the base station power amplifier. At the same time, it is necessary for environmental protection and energy saving. The base station power amplifier must also meet the requirements of high efficiency. Based on the above application requirements, this paper studies the application of envelope tracking technology to Doherty power amplifier. In order to ensure the high efficiency of the base station power amplifier at the same time to enhance the linearity of the system under the high power input state. The main work of this paper is based on the research of Doherty amplifier. An envelope tracking signal is proposed to control the peak gate voltage in the Doherty amplifier, by which the gate voltage can be reduced at low power input to achieve high efficiency. In the case of high power input, the grid voltage is raised, and the linearity is raised at the expense of a small part of efficiency. The research in this paper mainly includes: 1. The basic theory of power amplifier is studied. The basic principle of Doherty amplifier is analyzed. 2. The envelope tracking technology is analyzed and studied, and the structure of the current mainstream envelope tracking circuit is systematically summarized. 3. The influence of envelope tracking technology on the circuit performance of Doherty amplifier is studied, and the results of control carrier, peak power amplifier gate voltage and leakage voltage are compared. For the 2.59GHz LTE system, a circuit structure using envelope tracking to control the peak power amplifier gate voltage is proposed. In order to improve the linear performance of Doherty amplifier. 4. The envelope tracking Doherty amplifier is designed and fabricated, and tested in the laboratory. The test results show. Compared with the traditional Doherty amplifiers, the third-order intermodulation of the envelop tracking Doherty amplifiers is improved by about 3dBc in 8 dB power recoil. The efficiency only deteriorated by 2% or 4%.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN722.75;TN929.5
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本文编号：1485656