【正文】 I 摘 要 快速發(fā)展的無(wú)線通信對(duì)微波射頻電路如低噪聲放大器提出更高的性能。低噪聲放大器 (LNA)廣泛應(yīng)用于微波接收系統(tǒng)中，是重要器件之一，它作為射頻接收機(jī)前端的主要部分，其主要作用是放大天線從空中接收到的微弱信號(hào)，降低噪聲干擾，以供系統(tǒng)解調(diào)出所需的信息數(shù)據(jù)。它的噪聲性能直接決定著整機(jī)的性能，進(jìn)而決定接收 機(jī)的靈敏度和動(dòng)態(tài)工作范圍。而近年來(lái)由于無(wú)線通信的迅猛發(fā)展也對(duì)其提出了新的要求，主要為：低噪聲、低功耗、低成本、高性能和高集成度。所以本論文針對(duì)這一需求，完成了一個(gè) 聲放大器的設(shè)計(jì)。 本文從偏置電路、噪聲優(yōu)化、線性增益及輸入阻抗匹配等角度分析了電路的設(shè)計(jì)方法， 借助 ADS 仿真軟件的強(qiáng)大功能對(duì)晶體管進(jìn)行建模仿真，在這個(gè)基礎(chǔ)上對(duì)晶體管的穩(wěn)定性進(jìn)行了分析，結(jié)合 Smith 圓圖，對(duì)輸入輸出阻抗匹配電路進(jìn)行了仿真優(yōu)化設(shè)計(jì) ，設(shè)計(jì)了一個(gè)中心頻率為 、帶寬為 100MHz、輸入輸出駐波比小于 、 噪聲系數(shù)小于 2dB和增益 大于 15dB的 低噪聲 放大器 。 關(guān)鍵詞： 微波 ； 低噪聲放大器 ； 噪聲系數(shù) ； 匹配電路 ； ADS 仿真 II ABSTRACT Rapid growth of wireless data munications has increased the demand for high performance RFamp。Microwave circuits, Such as Microwave Low Noise Amplifiers. The LNA is one of the most important and broad ponents in Microwave munication system receiver, as the main part of the RF frontend receiver, the function of the low noise amplifier is amplifying the faint signal which incepted from air by the antenna. It can reduce the noise jamming, so as to demodulate right information for the system. The noise performance of the LNA will affect the performance of the whole system directly, and then deciding the sensitivity and dynamic working scope of the receiver. From the aspect of bias circuit, noise optimization, linear gain, impedance match, and the design methodology for LNA is analyzed, This article carries on the modelling simulation with the aid of the ADS simulation software39。s powerful function to the transistor, has carried on the analysis in this foundation to transistor39。s stability, has used the Smith circle diagram, to input the output impedance match circuit to carry on the simulation optimization design. a radio frequency power amplifier is designed, which has a centre , bandwidth 100MHz, I/O VSWR less than , Noise coefficient less than 2dB and Wattandgain 15dB. Key Words： microwave。 lownoise amplifier。 noise figure。 matching circuit。 ADS simulation 目 錄 1 引 言 ............................................................................................................................ 1 課題研究背景 ........................................................................................................ 1 低噪聲放大器簡(jiǎn)介 ................................................................................................ 2 低噪聲放大器的發(fā)展現(xiàn)狀 .................................................................................... 2 本課題的研究方法及主要工作 ............................................................................ 3 2 低噪聲放大器理論綜述 ................................................................................................ 5 史密斯圓圖 ............................................................................................................ 5 S 參數(shù) ..................................................................................................................... 6 長(zhǎng)線的阻抗匹配 .................................................................................................... 7 微波源的共軛匹配 ....................................................................................... 7 負(fù)載的匹配 ................................................................................................... 8 匹配方法 ....................................................................................................... 8 微帶線簡(jiǎn)介 ............................................................................................................ 8 偏置電路 ................................................................................................................ 9 3 低噪聲放大器的基本指標(biāo) .......................................................................................... 10 工作頻帶 .............................................................................................................. 10 帶寬 ...................................................................................................................... 10 噪聲系數(shù) .............................................................................................................. 11 增益 ...................................................................................................................... 12 穩(wěn)定性 .................................................................................................................. 12 端口駐波比和反射損耗 ...................................................................................... 13 4 低噪聲放大器設(shè)計(jì)仿真及優(yōu)化 .................................................................................. 15 指標(biāo)目標(biāo)及設(shè)計(jì)流程 .......................................................................................... 15 選取晶體管并仿真晶體管參數(shù) .......................................................................... 15 晶體管 S 參數(shù)掃描 .............................................................................................. 17 放大器的穩(wěn)定性分析 .......................................................................................... 19 設(shè)計(jì)輸入匹配網(wǎng)絡(luò) .............................................................................................. 21 匹配原理 ......................................................................................................21 計(jì)算輸入阻抗 ..............................................................................................23 單支節(jié)匹配電路 ..........................................................................................23 設(shè)計(jì)并優(yōu)化輸入輸出匹配網(wǎng)絡(luò) .......................................................................... 25 結(jié) 論 ............................................................................................................................... 30 參考文獻(xiàn) ............................................................................................................................. 32 致 謝 ............................................................................................................................. 34 天津職業(yè)技術(shù)師范大學(xué) 2021 屆本科生畢業(yè)設(shè)計(jì) 1 1 引 言 課題研究背景