3mm接收机前端关键技术研究

发布时间：2018-04-25 05:13

本文选题：W波段 + 接收机前端　；参考：《电子科技大学》2014年硕士论文

【摘要】：3mm波段是毫米波波段中的一个重要频段,中心频率为94GHz的大气“窗口”就位于此频段内。随着现代通信技术和军事电子技术的发展,3mm频段越来越受到研究人员的重视,然而由于加工工艺以及较高的研发成本等因素影响,国内对3mm频段电路与系统进行的研究以及报道较少。本文就是基于3mm接收机前端及其关键技术的研究而展开。本论文在对几种常用的接收机结构进行理论分析的基础上,结合本教研室以前成功设计3mm组件的经验,确定了本课题3mm接收机前端的最终设计方案。课题要求该前端分两部分制作:接收变频模块以及位于接收变频模块前的保护性开关。本振信号由外部接入,无需再另行设计本振支路。最终设计的接收机前端由3mm单刀单掷开关、低噪放、3mm功放、混频器和中频功放组成。接下来论文对3mm单刀单掷开关进行了详细研究。首先分析了PIN二极管的原理,给出了其在正反偏压下的等效电路;然后对SPST开关的主要参数和隔离度提高方法进行了讨论;最终确定了开关的基本电路结构。选用在毫米波波段传输损耗较低的鳍线作为传输线,在其上并联PIN二极管的方式来设计该开关。之后,从PIN二极管的选择、鳍线缝宽的确定、波导至鳍线过渡结构的设计以及低通滤波器的设计、整体电路的仿真等几方面来完成SPST开关的设计。该开关中对波导鳍线夹缝处能量的泄漏,采取以下方法处理:对接地一侧的夹缝,采用金属化通孔的方式来抑制能量泄漏;对非接地一侧,采用滤波器法来抑制能量泄漏。之后完成了SPST开关的制作和测试,测试结果显示:在90~95GHz内,该开关的插入损耗小于1.9dB,隔离度优于24.9dB,达到了设计要求。根据课题要求,尤其对外形尺寸和接口位置的要求,完成了3mm接收机前端中射频电路板、供电电路板和腔体的制作。对于腔体,由于其很复杂,分上、中、下三层来制作,中间腔体的正反面分别放置射频电路板和供电电路板。之后对装配好的接收机前端进行了调试,并完成了最终的测试工作。最后,对3mm接收机前端和开关的测试结果进行了分析,总结了相关经验。
[Abstract]:3mm band is an important frequency band in millimeter wave band. The atmospheric "window" with center frequency of 94GHz is located in this band. With the development of modern communication technology and military electronic technology, researchers pay more and more attention to the 3mm frequency band. However, due to processing technology and high R & D costs and other factors, There are few researches and reports on 3mm band circuits and systems in China. This paper is based on the research of the front end of 3mm receiver and its key technology. Based on the theoretical analysis of several commonly used receiver structures and the experience of designing 3mm components successfully in our teaching and research department, the final design scheme of the front-end of the 3mm receiver is determined in this paper. The subject requires that the front end be made in two parts: the receiving frequency conversion module and the protective switch located in front of the receiving frequency conversion module. The local oscillator signal is connected from the outside without the need to design the local oscillator branch separately. The receiver front end is composed of 3mm single pole single throw switch, low noise amplifier 3 mm power amplifier, mixer and if power amplifier. Then the 3mm single throw switch is studied in detail. Firstly, the principle of PIN diode is analyzed, and the equivalent circuit under positive and negative bias voltage is given. Then, the main parameters of SPST switch and the method of improving isolation degree are discussed. Finally, the basic circuit structure of the switch is determined. The fin line with low transmission loss in millimeter wave band is chosen as transmission line, and the PIN diode is connected to it to design the switch. After that, the design of SPST switch is completed from the selection of PIN diode, the determination of finline slit width, the design of waveguide to finline transition structure, the design of low-pass filter and the simulation of the whole circuit. In this switch, the energy leakage at the slot of the fin-line of the waveguide is dealt with as follows: for the gap on the ground side, the metallized through hole is adopted to suppress the energy leakage; for the non-grounded side, the filter method is used to suppress the energy leakage. The test results show that the insertion loss of the switch is less than 1.9 dB and the isolation degree is better than 24.9 dB in 90~95GHz. The RF circuit board, power supply circuit board and cavity in the front end of the 3mm receiver are fabricated according to the requirements of the subject, especially for the size of the shape and the position of the interface. For the cavity, due to its complexity, the upper, middle and lower layers are made, and the front and back of the middle cavity are placed on the RF circuit board and the power supply circuit board respectively. After that, the assembled receiver front-end is debugged and the final test work is completed. Finally, the test results of front end and switch of 3mm receiver are analyzed, and relevant experiences are summarized.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN851

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