K波段四次谐波低中频混频器研究

发布时间：2018-04-21 07:46

本文选题：四次谐波混频器 + 变频损耗　；参考：《电子科技大学》2015年硕士论文

【摘要】：在高频系统尤其是毫米波系统中,高频本振源的研制难度较大,要获得高性能系统,变频部分的一种可行方案是采用谐波混频技术。谐波混频技术可以有效降低本振源的研制难度,因而在实际工程中得到广泛应用。由于混频器的变频损耗、镜频抑制度、噪声系数等指标直接影响系统的整体性能,因此,对混频器的研究具有重要意义。本文通过分析近年来国内外高次谐波混频器的研究进展,并结合课题要求,研制工作在K波段的四次谐波低中频混频器。射频(RF)频率为24.07 GHz,本振(LO)频率为6.0 GHz。本课题的最终目标是研制低变频损耗的小型化四次谐波混频电路,具体内容有:1)混频方案、元部件的选取以及电路总体布局研究:包括比较并确定混频类型和采用的混频器件等。2)过耦合器的研究:为使RF与LO之间的隔离度高而且RF与LO信号有效加载至混频元件,文中采用了一种具有特定功能的耦合线过耦合器分别作为RF与LO信号的输入,同时实现LO与RF端口之间的良好隔离。3)闲置频率信号的处理:对四次谐波混频,为提高能量利用效率,减小混频器变频损耗,应对未参与混频的RF、LO以及二次闲频信号合理处置。4)中频(IF)信号的提取方案:为有效提取出IF信号并使IF输出端口与本振、射频端口隔离度高,需对IF滤波网络进行研究和设计。5)本振与射频回路以及输入匹配网络:根据电路布局需要,设计了一种变形扇形枝节来实现本振与射频回路,匹配网络部分则采用了平衡短截线实现电路的匹配。6)四次谐波混频器电路仿真得到的变频损耗最低仅6.3 dB,变中频工作与固定中频工作时变频损耗10 dB以下带宽分别可达1.2 GHz与2.7 GHz,且各端口之间有着较高隔离特性同时电路整体尺寸也进一步减小。7)作为本硕士论文的进一步拓展,通过在0-dB耦合器射频直通端口加载λ/4@4fLO开路枝节和PIN开关以及相应的直流偏置网络,通过控制开关的通断状态,可设计成一种具有多种工作状态的谐波混频器。
[Abstract]:In the high frequency system, especially in the millimeter wave system, the development of the high frequency local oscillator is difficult. To obtain the high performance system, a feasible scheme of the frequency conversion part is to adopt the harmonic mixing technology. Harmonic mixing technology can effectively reduce the difficulty of local oscillator development, so it is widely used in practical engineering. Because the frequency conversion loss, mirror frequency rejection and noise coefficient of mixer directly affect the overall performance of the system, it is of great significance to study the mixer. By analyzing the research progress of high order harmonic mixers at home and abroad in recent years, and combining with the requirements of the subject, the fourth harmonic low if frequency mixer working in K band is developed in this paper. The RF frequency is 24.07 GHz and the local oscillator frequency is 6.0 GHz. The ultimate goal of this project is to develop a miniaturized fourth harmonic frequency mixing circuit with low frequency conversion loss. The selection of components and the study of the overall layout of the circuit: including the study of comparing and determining the type of mixing and the unit of mixer etc. 2) over coupler: in order to make the isolation between RF and Lo high and the RF and Lo signals loaded into the mixing element effectively, In this paper, a coupling line over-coupler with special function is used as the input of RF and Lo signals respectively, and the good isolation of idle frequency signals between Lo and RF ports is realized at the same time. In order to improve the efficiency of energy utilization and reduce the frequency conversion loss of mixer, we should deal with the extraction scheme of RFLO and if (4) if signal without mixing: in order to extract if signal and make if output port and local oscillator effectively, RF port isolation is high, we need to study and design if filter network. 5) Local oscillator, RF loop and input matching network: according to the layout of the circuit, a deformed sector branch is designed to realize the local oscillator and RF loop. In the part of matching network, the balanced truncation line is used to realize the matching of circuit. 6) the fourth harmonic mixer circuit has the lowest frequency conversion loss of 6.3 dB, and the frequency conversion loss is less than 10 dB bandwidth when variable intermediate frequency operation and fixed intermediate frequency operation. It can reach 1.2 GHz and 2.7 GHz, with higher isolation between ports and a further decrease in overall circuit size (.7) as a further development of the Master's thesis. By loading 位 / 4FLO open branch and PIN switch and the corresponding DC bias network at the RF through port of the 0-dB coupler, a harmonic mixer with multiple working states can be designed by controlling the on-off state of the switch.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN773

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