高效率逆F类Doherty射频功率放大器研究

发布时间：2018-05-24 20:49

本文选题：Doherty功率放大器 + 逆F类　；参考：《宁波大学》2015年硕士论文

【摘要】：功率放大器作为发射机系统的重要组成,其性能直接决定了发射机输出信号的质量与传输距离。同时,功率放大器也是通信系统中能耗最高的单元,其高效性设计不仅可以减少电力消耗,而且能够降低系统对散热装置及电源的设计要求,提高系统工作的稳定性。LTE系统通过采用OFDM技术,在显著提高数据传输速率和频谱利用率的同时,也导致信号具有很高的峰均比(PAPR)。如何实现对高峰均比信号的高效线性放大,成为了4G系统中功放设计的关键技术。本文重点围绕逆F类Doherty功放的效率增强问题展开研究,主要工作包括以下4部分:(一):对功放的主要性能指标进行了综述,根据射频放大器设计中对增益、功率和噪声系数三个不同的性能需求,对应分析了双共轭匹配、功率匹配和噪声匹配三种不同的设计原则。(二):主要围绕Doherty结构的高效率回退性能展开研究。根据有源负载牵引理论,分析了Doherty结构中两路功放在不同工作状态下输出电压与电流、负载阻抗及效率等参数的变化,给出整体效率回退曲线,肯定了Doherty结构对高峰均比信号的处理能力。(三):主要围绕F类/逆F类、逆F类Doherty功放的效率增强技术展开研究。首先,介绍了F类/逆F类功放的工作原理,讨论了晶体管寄生参数对其开关性能的影响。接着,给出了几种包含寄生参数补偿的逆F类输出端谐波抑制网络结构,并对各结构进行了理论分析与参数计算。最后,将逆F类功放与Doherty结构进行了有机结合,提出了一种高效率的逆F类Doherty功放结构,对其工作过程中两路功放的基波和谐波阻抗的变化进行了分析,并对载波功放和峰值功放补偿线的作用和长度选取进行了详细的研究。(四):完成了高效率逆F类Doherty功放的仿真设计、PCB的制作与调试及数字预失真线性化等工作。单音测试结果显示,在930MHz处,功放回退7.5d B时漏极效率仍高达64.2%。910-950MHz频带内,功放回退8d B时漏极效率均保持在50%以上,输出功率均大于42.5d Bm。选用3载波WCDMA信号作为测试信号,经数字预失真线性化后,输出信号的上下边带ACPR分别为-35.39d Bc和-35.9d Bc。
[Abstract]:Power amplifier as an important component of transmitter system, its performance directly determines the quality of transmitter output signal and transmission distance. At the same time, the power amplifier is also the unit with the highest energy consumption in the communication system. Its high efficiency design can not only reduce the power consumption, but also reduce the design requirements of the heat dissipation device and the power supply. To improve the stability of the system. By using OFDM technology, the data transmission rate and spectral efficiency are significantly improved, and the signal has a high peak to average ratio (PAPR). How to realize efficient linear amplification of peak-to-average ratio (APR) signals has become a key technology in the design of power amplifier in 4G systems. This paper focuses on the efficiency enhancement of inverse F-type Doherty amplifier. The main work includes the following four parts: (1) the main performance indexes of the amplifier are summarized, according to the gain of RF amplifier design, There are three different performance requirements for power and noise coefficient. Three different design principles are analyzed: double conjugate matching, power matching and noise matching. (II) study on the high efficiency fallback performance of Doherty structure. According to the active load traction theory, the variation of output voltage and current, load impedance and efficiency of two power amplifiers in Doherty structure under different working conditions are analyzed, and the overall efficiency regression curve is given. The processing ability of Doherty structure to peak-to-average ratio (PAPR) signal is confirmed. (III) study on efficiency enhancement of F / inverse F, inverse F Doherty power amplifiers. Firstly, the working principle of class F / inverse F power amplifier is introduced, and the effect of transistor parasitic parameters on its switching performance is discussed. Then, several kinds of inverse F-output harmonic suppression network structure including parasitic parameter compensation are given, and the theoretical analysis and parameter calculation of each structure are carried out. Finally, the inverse F type power amplifier is combined with the Doherty structure, and a high efficiency inverse F type Doherty power amplifier structure is proposed. The changes of fundamental wave and harmonic impedance of the two power amplifiers are analyzed. The function and length selection of carrier power amplifier and peak power amplifier compensation line are studied in detail. (4) the simulation design of high efficiency inverse class F Doherty power amplifier and its fabrication and debugging as well as digital predistortion linearization are completed. The results of single-tone test show that at 930MHz, the drain efficiency is still higher than that in the 64.2%.910-950MHz band at 7.5 dB, and the drain efficiency is above 50% at 8 dB, and the output power is more than 42.5 dB. After digital predistortion linearization, the upper and lower sideband ACPR of the output signal are -35.39dBc and -35.9dBc, respectively.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN722.75

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