摘要现代电子科学与通信技术发展迅速，对微波射频电路的设计及性能指标的要求也日益提高。低噪声放大器作为微波射频电路中接收系统的关键组件，对于整个接收机的性能起决定性作用。性能良好的低噪声放大器应具有低噪声、高增益、高功率等特点，在设计时需选择合适的晶体管。

由于C波段在卫星通信系统、雷达系统中有较高的应用，所以论文在分析放大器的基本理论与工作原理的基础上着重研究了工作在C波段的低噪声放大器，使用ATF34143晶体管设计了一个两级级联的低噪声放大器并运用ADS平台对电路系统进行了仿真和优化。最终得到一个工作在3。8-4。2GHz频段，噪声系数小于1dB，增益大于24dB，驻波比小于2dB的低噪声放大器，很好的满足了卫星接收系统对于低噪声放大器的设计指标。78810

毕业论文关键词  卫星接收系统  C波段  低噪声放大器  级联

毕业设计说明书外文摘要

Title   The Design of Microwave Low Noise Amplifier                     

Abstract With the rapid development of modern electronic science and communication technology, the performance requirements of microwave RF circuits are also getting higher and higher。 Low noise amplifier, which is the key components of the receiving system, plays a decisive role in the performance of the entire receiving system。 The low noise amplifier with good performance should be with low noise, high gain, high power and so on。 And it is required to pay attention to the selection of the transistor。

As the C band is widely applied in the satellite communication system and radar system, the article not only studies the basic theory and working principle of amplifier, but also focuses on the LNA operating at C band。 A two stage cascade low noise amplifier is designed using ATF34143 transistor。 The circuit system is optimized by using ADS simulation software。 Finally we get an LNA which works in the 3。8-4。2GHz band, with a noise figure of 0。7dB, a gain greater than 24dB and standing wave ratio less than 2dB。 And it satisfies the design indexes of low noise amplifier for satellite receiving system

Keywords  satellite receiving system   C band   low noise amplifier   cascade

目   次

1  引言 2

1。1  放大器的分类及作用 3

1。2  低噪声放大器研究的意义 3

1。3  国内外发展现状 5

1。4  论文主要工作安排 6

2  低噪声放大器的基础理论 8

2。1  低噪声放大器的基本原理 8

2。2  放大器的特性指标 8

2。3  噪声系数 9

2。4  稳定性分析 10

2。4。1  稳定性圆判断 10

2。4。2  稳定性的改善方法 10

2。5  增益、驻波比和动态范围 11

2。5。1  放大器的功率增益及平坦度 11

2。5。2  输入输出驻波比