摘要低噪声放大器(Low-Noise Amplifier, LNA)是无线接收机的重要组成部分，它是接收机的第一个有源元件。低噪声放大器的主要作用是放大天线从天空中接收到的微弱信号，降低噪声干扰，以供系统解调出所需的信息数据。对低噪声放大器的基本要求是：噪声系数低、足够的功率增益、工作稳定可靠、足够的带宽和较大的动态范围等。60090

本文在线性二端口网络的理论基础上，总结了低噪声放大器设计中遇到的问题，包括放大器噪声系数的计算、提高晶体管稳定性方法及匹配电路的设计的方法等等问题。应用微波电路仿真软件 ADS 设计了频率范围为2.4GHz～2.5GHzISM频段的低噪声放大器，其性能指标为：噪声系数NF<0.7dB，增益Gain>15dB。该放大器采用Agilent公司的低噪声放大管进行了放大，在设计的过程中使用ADS软件对放大器的偏置电路，输入、输出匹配电路进行了设计优化。在稳定性的设计中引入了源级串联负反馈，提高了放大器的稳定性；输入输出端分别采用了最小噪声匹配和负载匹配到50Ω的方法对放大器进行了输入、输出匹配电路的设计，使低噪声放大器实现较小的噪声系数，仿真结果表明，放大器的噪声系数小于 0.7dB，带内增益在16dB左右，输入输出回波损耗均小于-10dB，低噪声放大器的性能良好。60090

关键词：低噪声放大器  噪声系数  增益  负反馈  匹配网络

毕业设计说明书（毕业论文）外文摘要

Title The design and simulation of low noise amplifier with ADS 

Abstract

Low Noise Amplifier is one of the key components of the wireless Receiver, it is the first active component in the system. The main effect of the LNA is to amplify the weak signals received from the antenna, reduce the noise interference, so that the required information can be demodulated. The basic requirements of the LNA include: low noise figure, enough power gain, reliable work stability, sufficient bandwidth and the wide dynamic range.

On the basis of the linear two-port network theory, several problems in development of the cascade amplifier which include the calculating of the noise coefficient, the designing of the matching circuit and the improving method of the stability of LNA, etc. are summarized in this paper. A low noise amplifier which has a frequency range of 2.4GHz to 2.5GHz was designed by using the microwave circuit simulation software Advanced Design System ,and the Performance Indexes are shown as follows: less than 0.7dB noise figure. This amplifier carries out one amplification the Agilent-company. In the design process, the input and output matching circuit of the amplifier and the bias circuit was designed and optimized by using ADS commercial software. The simulation result shows: the noise figures less than 0.7dB, the gain is about 16dB, the input and output VSWR is less than -10dB, the LNA have a good performance.

Keywords：low-noise amplifier（LNA）noise figure  gain  stability  negative feedback, Match Network.

目  录

1  引言 1

1.1  研究背景 1

1.2  低噪声放大器发展现状 3

1.3  本文的内容安排 4

2  低噪声放大器的主要性能指标 6

2.1  噪声系数NF 6

2.2  放大器增益G 6

2.3  増益、噪声和动态范围之间的关系 7

2.4  稳定性分析 7

2.5  低噪声放大器的设计方法