基于左手传输线的耦合线研究

发布时间：2018-10-08 20:25

【摘要】：左手传输线是指介电常数和磁导率同时为负值的人工合成传输线。电磁波在其传播时,波矢量(?)、电场(?)和磁场(?)之间的关系符合左手定律。由于左手传输线在低频阶段具有很大的慢波系数,因此可以利用左手传输线设计出小型化的微波器件,但是关于左手传输线和左手耦合线的研究还处于探索阶段,尤其在左手传输线和左手耦合线的模态萃取方面。本论文主要提出了基于散射参数的左手传输线周期解和左手耦合线的周期解。其利用周期Bloch-Floquet边界,精确的计算出对称型左手耦合线和非对称型左手耦合线的复数传播常数,并将上述方法用Mathematica程序实现。首先本论文设计了不同的串联电容和并联电感,利用本论文提出的基于散射参数的左手传输线周期解和左手耦合线的周期解,分析不同个数周期结构的左手传输线和左手耦合线的色散特性曲线。当周期结构达到一定个数时,左手传输线和左手耦合线的色散特性曲线收敛。传统的基于集总参数等效电路模型的方法计算的色散曲线与本论文一个周期结构的周期解基本一致,但是此时的色散曲线还没有收敛。通过设计不同的串联电容,可以改变合成左手耦合线的耦合带宽;设计不同的并联电感,可以改变合成左手耦合线的前向耦合量。另外本论文还提出了合成非对称型左手耦合线的方法。利用标准的130 nm CMOS工艺对本论文提出的对称型左手耦合线和非对称型左手耦合线进行下线与测试。论文设计了三种不同类型的定向耦合器,第一种是右手/左手高指向性的定向耦合器,该耦合器在实现3-dB耦合度的同时能够实现38dB的隔离度;第二种是对称型左手10-dB前向耦合器,该耦合器的长度只有0.108λg,远远小于传统右手的前向耦合器的长度;第三种是非对称型左手3-dB前向耦合器,该前向耦合器由于是靠电感耦合,与对称型左手耦合器相比,更能减小耦合器的尺寸。第二种和第三种前向耦合器利用标准的CMOS 130 nm 1P8M工艺下线并进行测试。另外由于实验室太赫兹平台只能测量两端口的微波器件,因此论文还推导了利用两端口的矢量网络分析仪测量四端口微波器件的方法。最后本论文利用缺陷地结构的对称型左手耦合线设计了一个小型化天线,天线操作在差分激励左手耦合线的辐射频段,与传统的利用单根左手传输线制作的天线相比,该种天线具有更大的辐射效率和最大增益,天线的尺寸只有165μm′90μm。
[Abstract]:Left-handed transmission line is a synthetic transmission line with negative permittivity and permeability. When the electromagnetic wave propagates, the wave vector (?) Electric field And magnetic field (?) The relationship between them obeys the law of left hand. Since left-handed transmission lines have large slow-wave coefficients at the low frequency stage, miniaturized microwave devices can be designed using left-handed transmission lines, but the research on left-handed transmission lines and left-handed coupling lines is still in the exploratory stage. Especially in the mode extraction of the left-handed transmission line and the left-handed coupling line. In this paper, the periodic solution of left-handed transmission line and the periodic solution of left-handed coupling line based on scattering parameters are presented. By using periodic Bloch-Floquet boundary, the complex propagation constants of symmetric left-handed coupling line and asymmetric left-handed coupling line are calculated accurately, and the above method is realized by Mathematica program. First of all, different series capacitors and parallel inductors are designed in this paper. The periodic solutions of left-handed transmission lines and left-handed coupling lines are proposed based on scattering parameters in this paper. The dispersion characteristic curves of left-handed transmission lines and left-handed coupling lines with different number of periodic structures are analyzed. When the periodic structure reaches a certain number, the dispersion characteristic curve of the left-handed transmission line and the left-handed coupling line converges. The dispersion curve calculated by the traditional method based on lumped parameter equivalent circuit model is basically consistent with the periodic solution of a periodic structure in this paper, but the dispersion curve does not converge at this time. By designing different series capacitors, the coupling bandwidth of the composite left-handed coupling line can be changed, and the forward coupling amount of the composite left-handed coupling line can be changed by designing different parallel inductors. In addition, a method of synthesizing asymmetric left-handed coupling wires is proposed. The symmetrical and asymmetric left-handed coupling lines proposed in this paper are tested by the standard 130 nm CMOS process. In this paper, three kinds of directional couplers are designed. The first is the high directivity of the right hand / left hand coupler. The coupler can realize the 3-dB coupling degree and the isolation degree of the 38dB at the same time. The second is a symmetric left-handed 10-dB forward coupler, which has a length of only 0.108 位 g, which is much smaller than that of the traditional right-handed forward coupler, and the third type of asymmetric left-handed 3-dB forward coupler, which is coupled by inductance. Compared with the symmetrical left hand coupler, the size of the coupler can be reduced more. The second and third forward couplers are offline and tested using the standard CMOS 130 nm 1P8M process. In addition, because the terahertz platform can only measure two-port microwave devices, the method of measuring four-port microwave devices using two-port vector network analyzer is also deduced in this paper. Finally, a miniaturized antenna is designed using the symmetric left-handed coupling line of the defective ground structure. The antenna operates in the radiation frequency band of the differential excitation left-handed coupling line, compared with the traditional antenna fabricated from the single left-handed transmission line. The antenna has higher radiation efficiency and maximum gain. The size of the antenna is only 165 渭 m ~ 90 渭 m.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN622

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