高温超导多通带滤波器的研究

发布时间：2018-04-21 22:20

本文选题：高温超导薄膜 + 多通带滤波器　；参考：《天津理工大学》2015年硕士论文

【摘要】：利用高温超导薄膜材料可以设计制作性能优异的微带滤波器,由于超导薄膜材料的表面电阻在微波射频频段,要比常规导体铜材料低1~3个数量级。因此可以用来设计制作高阶数的高温超导滤波器,其插入损耗可以保持很低的水平(通常可以控制在0.5d B以下)。高温超导滤波器因此具有极高的带外抑制,近乎为矩形的选频窗口,大幅度节省了过渡带宽。原有射频接收系统采用高温超导滤波器替换以后,明显提高了基站通信接收端的灵敏度,扩大了信号覆盖范围,增强了对干扰信号的抑制,消除了互调制响应,同时将滤波器放在接收机最前端,有效的保护了低噪声放大器,使其避免过强信号的冲击饱和,而不增加系统的整体噪声系数。所以高温超导滤波器在民用通信、警用集群通讯、军事抗干扰通讯、以及雷达精确制导、舰船飞行器精密导航等方面有着极强的应用潜力。由于所有的通信频段几乎都集中在射频微波频段,加之现有通讯协议频段的更新以及许多新的通讯协议提出,使频谱资源变得越来越紧张。而且同一协议的不同频段间又间隔着其它通讯设施的频段,而许多带通滤波器的组合将给通讯基站接收端设备带了沉重负担,不但增加了设备占地空间,还增加了系统后期解调难度。所以在一块芯片上同时实现对多个频段的同时通讯,可以有效减少系统接收设备的损耗,减小设备整体体积,实现设备的小型化,降低成本。本文主要结合频率资源日益紧张的问题以及高温超导材料在制作滤波器方面的优势,设计实现了两款多通带高温超导滤波器。首先设计了一款双通带高温超导滤波器,滤波器采用传统级联结构,分别按照指标要求对带通电路、带阻电路单独设计,将两种电路级联实现双通带特性,滤波器采用以铝酸镧为衬底的镝钡铜氧高温超导薄膜制作,测试环境为低温真空。其次设计了一款三通带高温超导滤波器,滤波器设计是在带通电路基础上,通过非邻近谐振器间引入强交叉耦合,将理论传输零点引入带内,设计出了两个阻带。在设计中给出了电路的理论耦合矩阵参数的优化方法,并详述了电磁场仿真软件搭建电路方法。本文最终利用高温超导薄膜材料实现了双通带与三通带滤波器,两款滤波器经仿真验证都显示出了良好的多通带特性,证实了基于以上理论实现多通带的可行性。制作出的双通带滤波器经过低温测试带内插损优于0.2d B,并在低频端产生了寄生的传输零点,增强了带外抑制。
[Abstract]:Microstrip filters with excellent properties can be designed and fabricated by using HTS thin film materials. Because the surface resistance of the superconducting thin films is in the microwave RF frequency band, it is 1 ~ 3 orders of magnitude lower than that of conventional conducting copper materials. Therefore, it can be used to design and fabricate high-order HTS filters, and the insertion loss can be kept at a very low level (usually controlled below 0.5 dB). As a result, HTS filters have extremely high out-of-band suppression and a rectangular frequency window, which greatly saves the transition bandwidth. After replacing the original RF receiver with HTS filter, the sensitivity of the base station communication receiver is obviously improved, the signal coverage is enlarged, the interference signal is suppressed, and the mutual modulation response is eliminated. At the same time, the filter is placed at the front of the receiver, which effectively protects the low noise amplifier from the shock saturation of the overstrong signal and does not increase the overall noise coefficient of the system. So HTS filter has great potential in civil communication, police trunking communication, military anti-jamming communication, radar precision guidance, ship aircraft precision navigation and so on. Since almost all the communication frequency bands are concentrated in the RF and microwave frequency band, together with the updating of the frequency band of the existing communication protocol and many new communication protocols, the spectrum resources become more and more tight. Moreover, the different frequency bands of the same protocol are spaced between the frequency bands of other communication facilities, and the combination of many bandpass filters will bring a heavy burden to the equipment at the receiving end of the communication base station, which not only increases the space occupied by the equipment, It also increases the difficulty of system demodulation. So the simultaneous communication of multiple frequency bands on a single chip can effectively reduce the loss of the system receiving equipment, reduce the overall volume of the equipment, realize the miniaturization of the equipment, and reduce the cost. In this paper, considering the shortage of frequency resources and the advantages of HTS materials in making filters, two kinds of multiband HTS filters are designed and implemented. First, a double-pass high-temperature superconducting filter is designed. The filter adopts the traditional cascade structure. The band-pass circuit and the band-stop circuit are designed separately according to the requirements of the index. The two circuits are cascaded to realize the double-pass-band characteristic. The filter is fabricated by dysprosium barium copper oxide high temperature superconducting thin film on the substrate of lanthanum aluminate. The test environment is low temperature vacuum. Secondly, a three-pass high-temperature superconducting filter is designed. Based on the bandpass circuit, a strong cross-coupling is introduced between the non-adjacent resonators, and the theoretical transmission zeros are introduced into the band, and two stopbands are designed. In the design, the optimization method of the theoretical coupling matrix parameters of the circuit is given, and the circuit method of the electromagnetic field simulation software is described in detail. In this paper, double pass band filter and three pass band filter are realized by using HTS thin film material. The simulation results show that the two filters have good multi pass band characteristics, which proves the feasibility of realizing multi pass band based on the above theory. The band insertion loss of the double pass band filter measured at low temperature is better than 0.2 dB, and the parasitic transmission zero is generated at the low frequency end, which enhances the out-of-band suppression.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN713.5

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