【作者】 徐蕾；

【导师】 郭伟；

【作者基本信息】 华中科技大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 近年来,随着微波技术的进步,微波接收机也在飞速地发展。而接收机射频前端的设计往往对整个系统的非线性指标、噪声系数、稳定度、灵敏度、增益等重要特征起着决定性的作用。因此,对接收机射频前端系统的研究有着重要的实际意义。本课题的任务是设计制作一套接收机射频前端系统,其中带通滤波器、低噪声放大器及锁相环频率源等三个关键模块是本论文关注的重点。论文详细的介绍了接收机射频前端系统中三个关键模块的原理和设计方法,并给出了本课题的设计实例和测试结果。首先,本文简要说明了课题背景及论文的主要工作。其次,简述了接收机的主要参数及几种常见的接收机系统结构。然后,分析了发夹型微带带通滤波器的电磁耦合特性及设计方法,给出了中心频率为900MHz的带通滤波器的设计过程及仿真测试数据;详细阐述了平衡式放大器的工作原理及其匹配、功率增益、稳定性及噪声性能,给出了采用该电路形式的低噪声放大器的仿真设计过程及测试结果;概述了频率合成技术,分析了锁相环的基本工作原理、稳定性及噪声性能,给出了采用Si4133芯片设计的830MHz锁相环频率合成器的设计电路及测试数据;最后,总结了本人完成的工作并提出了改进方向。在设计过程中,发夹型微带带通滤波器主要考虑其通带平坦性及过渡带陡峭程度,低噪声放大器以增益、输入输出驻波比、噪声系数为优化指标,频率源主要从输出频率及其功率、相位噪声来考察设计效果。测试结果表明,在误差范围内,模块均满足设计要求。更多还原

【Abstract】 With the progress of microwave techniques,the receiver are developing fast recently. The RF front-end of receiver is a decisive factor producing an effect on important properties such as nonlinearity,noise factor,stability,sensitivity,gain.Therefore,research on the RF front-end of receiver have important practical meanings.Our project is to design and manufacture a RF front-end system of receiver.This thesis is focus on the three key modules which are radio frequency bandpass filter,low noise amplifier,PLL synthesizer.The fundamental theories and design approaches of the three key units in receiver RF front-end are introduced in this thesis. Moreover, the design examples and testing results of all three modules are given. First,the technical background of the project and main contents of this thesis are explained briefly. Second,major parameters and common organizations of receiver are recommendated. Third,the general theories about microstrip filter and the electromagnetic coupling characteristics and design methods of microstrip hairpin-resonator bandpass filter are suggested,the design process,simulation and testing outcomes of the hairpin filter module working on 900MHz is shown. Then,basic principles of balanced amplifier are analyzed in great detail,containing impedance matching, gain, stability and noise performance, the LNA adopted balanced structure is stated including its design procedures and testing results. Finally,frequency synthetic technique and the theory of PLL is elaborated, the circuit and testing results of the PLL synthesizer applying Si4133 is demonstrated.In the course of the design, we mainly considered passband platness and abrupt transition band of hairpin bandpass filter; taken gain,input/output VSWR,noise factor of LNA as optimization goals; checked frequency and power of output,phase noise of PLL synthesizer. All the testing results of the three modules meet design requirements within the range of allowable error.更多还原