【作者】 刘鹏；

【导师】 李家林；

【作者基本信息】 电子科技大学 ， 无线电物理， 2017， 硕士

【摘要】 随着无线通信技术的快速发展,高性能的射频微波器件获得广泛关注。作为发射机前端的核心部件,功率放大器的带宽、输出功率、效率、线性度等性能对通信系统的性能起着决定性作用。近年来,运行在不同的通信标准与频段的通信系统越来越多,而每个通信标准都需要发射机以足够的功率向天线馈送能量,多个射频功率放大器同时工作时不仅会增加功耗,还会增加建设成本。因此,能够将工作在不同频段的功率放大器集成于同一平台,并在此平台上实现相互协作已成为当前一个重要的研究课题,因而双频/多频段高效射频功率放大器的研究具有重要价值。同时,随着GaN半导体技术的逐渐成熟,基于GaN HEMT的功率放大器已成为研究热点。本文首先介绍了功率放大器的高效率技术和线性化技术以及多频功率放大器国内外研究历史和现状,然后介绍了功率放大器的基本性能指标,并从理论方面对平衡式放大器进行了分析。其次,基于双频平衡式功率放大器,对其中的关键部件:双频功率放大器、双频分支线耦合器、双频45°移相功分器进行了理论分析和设计。最后,通过有机集成上述各部分工作,设计2.4/5.2 GHz双频平衡式功率放大器并给出了全波仿真和实测结果。本文工作和成果主要体现在以下几个方面:(1)首次提出双频宽带45°移相功分器,基于ABCD矩阵推导了π型移相网络并重点分析了其相位变化率特性,实现了双频相位补偿,提高了相位带宽。(2)提出一种新型双频四分之一波长阻抗变换器,并基于该阻抗变换器设计实现了双频分支线耦合器。(3)设计了双频功率放大器。结合双频无源技术设计双频匹配电路、双频偏置电路、双频隔直电路等结构,并给出了完整的双频功率放大器设计步骤。(4)研制出一台2.4/5.2 GHz双频平衡式功率放大器样机,并给出完整的全波仿真和测试结果。本文设计的双频带移相功分器、双频带分支线耦合器、双频带平衡式功率放大器结构新颖、性能良好,具有重要的应用价值。更多还原

【Abstract】 With the continuous development of wireless communication technology,high-performance RF microwave devices have been paid great attentions.As a key component in a transmitter,the bandwidth,output power,efficiency and linearity of a power amplifier play critical roles in communication systems.In recent years,communication systems operate in different communication standards and different frequency bands,where transmitters require sufficient power to feed antenna.Several power amplifiers operated simultaneously not only result in high power consumption,but also increase the cost.Therefore,it is of great significance to study power amplifiers integrated at different frequency bands.Meanwhile,with the advance of GaN semiconductor technology,design of GaN HEMT based power amplifier has become a hot topic.This thesis first introduces the history and latest development about the efficiency and linearization techniques as well as the multiple frequency technology of power amplifiers.Then we introduce the basic performance parameters of the power amplifier,and analyze the balanced amplifier theoretically.The key components for dual-frequency balanced power amplifier,for instance,dual-band power amplifier,dual-band branch line coupler,dual-band 45° phase shift power splitter,are respectively discussed.Finally,the 2.4 and 5.2GHz balanced power amplifier,by integrating the above components,are developed.Both full-wave simulations and measurements are presented.Contributions of this work include(1).A dual-frequency broadband power splitter with 45? phase shifts is studied in depth.The architecture is based on the ?-type network to realize the flat phase compensation at the two bands.(2).A dual-frequency quarter-wavelength transformer is discussed and further integrated into the branch-line coupler to implement the dual-band responses.(3).A dual-band power amplifier centered at 2.4 and 5.2 GHz is developed,and further,(4).Balanced power amplifier for dual-band application is developed and confirmed by EM simulations and measurements.In general,the dual-band phase shift power divider,3dB branch-line coupler and balanced power amplifier studied in this paper feature novel structure and good performance,making it potential in engineering applications.更多还原