基于倒置变换器的柔性共面波导微波滤波器的研究

发布时间：2019-04-28 08:10

【摘要】：共面波导结构(Coplanar Waveguide)因其具有寄生参量小、电路集成密度大、色散性好等优点,在现代无线通信的滤波器设计中得到了广泛的应用。倒置变换器可以对集总电路中的电容电感进行倒置变换使其便于微波结构实现,在微波滤波器设计中至关重要。随着柔性电子技术的快速发展,柔性介质逐渐应用于例如滤波器、天线等微波器件的设计中,具有柔软性和薄膜性等特点。因此,关于弯曲对器件性能影响的研究是十分必要的。本论文首先研究倒置变换器在平直状态与弯曲状态下的设计方法,利用微波网络中传输矩阵级联特性,分别得到倒置变换器两端传输线的传输矩阵和整个倒置变换器结构的传输矩阵,借助Matlab编程间接求出倒置变换器的JK值和负长度随频率的变化关系。并基于柔性介质设计了六种倒置变换器结构,包括缝隙电容J变换器、十字电感K变换器、1/4波长高低阻抗倒置变换器、交指电容J变换器、高低阻抗十字K变换器,详细分析了倒置变换器弯曲程度对其性能的影响,加以归纳总结。根据微波滤波器设计理论,利用提出的几种倒置变换器结构设计了三种基于柔性介质的共面波导微波滤波器,分析了共面波导微波滤波器弯曲程度对其中心频率、相对带宽、插入损耗等性能的影响。最后加工出一种共面波导微波滤波器实物,分别在平直状态与弯曲状态下对滤波器进行测试,并与仿真结果进行对比分析,发现弯曲程度不同会造成滤波器中心频率少量偏移,中心频率的偏移量在6%以内,而对回波损耗和插入损耗几乎无影响。
[Abstract]:Coplanar waveguide structure (Coplanar Waveguide) has been widely used in the filter design of modern wireless communication because of its advantages such as small parasitic parameters large integrated circuit density good dispersion and so on. The invert converter can invert the capacitance inductor in lumped circuit to make it easy to realize microwave structure, which is very important in the design of microwave filter. With the rapid development of flexible electronic technology, flexible media are gradually used in the design of microwave devices such as filters and antennas, which have the characteristics of flexibility and thin film. Therefore, it is necessary to study the effect of bending on device performance. In this paper, firstly, the design method of inverted converter in flat state and bending state is studied, and the cascading characteristics of transmission matrix in microwave network are used. The transmission matrix of the two ends of the inverted converter and the transmission matrix of the whole inverted converter structure are obtained, and the relationship between the JK value and the negative length of the inverted converter with frequency is obtained indirectly by means of Matlab programming. Six inverters are designed based on flexible medium, including slot capacitor J converter, cross inductance K converter, 1? 4 wavelength high and low impedance invert converter, AC finger capacitor J converter and high impedance cross K converter. The influence of bending degree of inverted converter on its performance is analyzed in detail and summarized. According to the theory of microwave filter design, three kinds of coplanar waveguide microwave filters based on flexible medium are designed by using several invert converter structures proposed. The bending degree of the microwave filters with coplanar waveguides is analyzed with respect to their central frequency and relative bandwidth. Insertion loss and other effects of performance. Finally, a kind of coplanar waveguide microwave filter is fabricated. The filter is tested in the flat state and the bending state, and compared with the simulation results. It is found that the different bending degree will result in a small deviation of the center frequency of the filter. The offset of center frequency is less than 6%, but has little effect on echo loss and insertion loss.
【学位授予单位】：南京邮电大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN713

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