【作者】 孙超；

【导师】 房晓勇；

【作者基本信息】 燕山大学 ， 无线电物理， 2016， 硕士

【摘要】 低噪声放大器是微波接收系统中较为重要的部件之一,处在系统的前端,主要功能是把接到的信号线性放大,并抑制其中的噪声。它的性能优劣会直接决定着整个接收系统的灵敏度以及噪声性能。随着现代卫星通讯、雷达、导航术的迅猛发展,性能更佳、实用性更强的低噪放研发受到了越来越广泛的关注。论文主要内容如下:首先,对低噪声放大器的研究背景、意义及现状进行简要介绍,并对设计中所使用的微带相关理论进行详细概括。通过微波传输线的简述,引出微带线的特性及参数计算等内容,并分析了带有微带线结构的匹配电路的设计。其次,对微波网络进行了简要的概述,对二端口网络、S参数和史密斯圆图的概念进行了解释。接着介绍了低噪放设计中涉及的性能指标,主要通过围绕噪声、稳定性、增益、驻波比的概念及意义进行详细的分析和阐述。最后,运用射频设计工具ADS2013,结合低噪放的偏置电路和稳定性,采用源极串联负反馈方法,选取AVAGO公司的晶体管VMMK-1218,使用微带线匹配电路以及两级级联结构。通过仿真,低噪放在8.7~9.3GHz频段范围内噪声系数小于0.2dB,增益大于26dB,驻波比均小于1.4,性能良好,满足了设计指标的需求。更多还原

【Abstract】 Low noise amplifier is one of the important parts in the microwave receiving system,and located in the front end of the receiving system. The main function of LNA is to amplify the received signal and restrain the noise. It’s performance will directly decide the quality of the whole receiving system’s sensitivity and noise performance. With the rapid development of the satellite communications, radar, navigation technology, people pay more and more attentions to the research and design of the better performance and skillful LNA. The main contents are as follows:Firstly, this paper make a general introduction through the research background,significance and the status of LNA. And then this paper make a detail summary about the theory of the micro-strip theory which are used in the thesis. We get the character of micro-strip line and the calculation of parameters by the brief introduction of microwave transmission line. We analyze the design of the matching circuit with micro-strip line structure.Secondly, The microwave network is briefly introduced in this paper, explaining the concepts of the two-port network, S-parameters and Smith chart. And then this paper introduce the performance index involved in the LNA design, Mainly through the detailed analysis and elaboration of the concept and significance of noise, stability, gain, VSWR.Finally, this paper combine with bias circuit and the stability of LNA, with source series negative feedback and RF design tool ADS 2013, the LNA which configures series of two stages cascaded transistors VMMK-1218 from AVAGO company, and the matching circuits is design with micro-strip line. By means of the simulation, the LNA exhibits operating with 8.7~9.3GHz, noise figure less than 0.2d B, gain more than 26 d B, all the two VSWR less than 1.4, and has a good performance, meets the needs of the design index.更多还原