宽带Doherty功放技术研究

发布时间：2018-10-23 20:23

【摘要】：Doherty功率放大器(DPA)是一类利用负载牵引技术提升输出功率回退区效率的功率放大器。自1936年提出以来,’DPA已被证实适用于采用高峰均比调制信号的现代通信系统。现今宽带／多频带的通信系统的研究越来越受到关注,因此如何提升Doherty功率放大器的带宽性能已成为研究热点。本文设计实现了一款基于Doherty的宽带功率放大器,提供了一种宽带Doherty功放的设计思路与方法。主要完成了以下工作：1)在Doherty结构中,分析了各个设计参数(功分比、偏置电压、功率合成网络)、功放管参数以及功放性能(输出功率、漏极效率、带宽)的内在联系,并在此基础上提出了一种Doherty设计参数计算方法。2)基于一款等分的宽带耦合器,使用ADS的优化控件对其进行优化设计,从而得到新型的不等分宽带耦合器,能够在1.5 GHz至2.2 GHz间实现2.5 dB-6 dB不等的功分比特性。3)设计了新型的补偿线网络以替代传统的单段补偿线,从而以牺牲一定匹配性能的代价使功率放大器获得约900 MHz的工作带宽。并且,该补偿网络在功放调试后期可作为主要的调试模块。4)仿真、加工调试并测试了所提出的宽带Doherty功率放大器的性能。测试结果表明,该宽带DPA实现了900 MHz的工作频带以及回退6 dB时大于30%的带内平均漏极效率,满足了设计指标要求。与同类型功放相比,该宽带DPA的相对带宽指标(51.4%)处于领先水平,由此证明了本文所提出的设计参数计算方法以及宽带DPA结构的可行性。
[Abstract]:Doherty power amplifier (DPA) is a kind of power amplifier which uses load traction technology to improve the efficiency of output power fallback region. Since its introduction in 1936, 'DPA has been proved to be suitable for modern communication systems using peak-to-average ratio modulation signals. Nowadays, more and more attention has been paid to the research of broadband / multi-band communication systems, so how to improve the bandwidth performance of Doherty power amplifiers has become a hot research topic. This paper designs and implements a wideband power amplifier based on Doherty, and provides a design idea and method of wideband Doherty power amplifier. The main works are as follows: 1) in the Doherty structure, the internal relations of the design parameters (power ratio, bias voltage, power synthesis network), power amplifier parameters and power amplifier performance (output power, drain efficiency, bandwidth) are analyzed. On this basis, a method for calculating the design parameters of Doherty is proposed. 2) based on an equally divided broadband coupler, a new type of unequal wideband coupler is obtained by using the optimization control of ADS. A novel compensation line network is designed to replace the traditional single-segment compensation line. The bandwidth of the power amplifier is about 900 MHz at the expense of matching performance. Moreover, the compensation network can be used as the main debugging module in the later stage of power amplifier debugging. 4) Simulation, processing, debugging and testing the performance of the proposed wideband Doherty power amplifier. The test results show that the wideband DPA achieves an operating band of 900 MHz and an average in-band drain efficiency of more than 30% at 6 dB, which meets the design requirements. Compared with the same type of power amplifier, the relative bandwidth index of the broadband DPA (51.4%) is in the leading level, which proves the design parameter calculation method proposed in this paper and the feasibility of the broadband DPA structure.
【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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