天线互耦表征及去耦方法的研究

发布时间：2018-04-24 11:14

本文选题：天线互耦 + 电流分布　；参考：《东南大学》2016年博士论文

【摘要】：一直以来,天线互耦作为天线领域的重要研究内容,备受研究人员的关注。互耦对各种无线通信和探测系统性能的影响不容小觑。例如,互耦会恶化收发隔离度、降低系统容量、引入扫描盲点以及影响系统的设计精度。因此开展天线互耦问题的研究和探索解决措施具有重要意义和应用价值。本文从天线互耦表征和去耦方法两方面展开研究,提出了一种基于天线电流分布表征互耦的电流失真参数,并研究设计了基于多种方法的去耦结构。主要工作和研究成果如下：(1)提出了一种表征天线互耦的参数一电流失真参数。该参数给出了有无互耦情况下天线电流分布的相对差异,从而表征了互耦对电流分布的影响。通常使用散射参数表征天线互耦,然而该参数只反映了天线端口的特性,而且端口特性不能完全描述互耦对天线的影响,这样就有必要研究表征互耦的其他参数。由于天线的电流分布同时决定了其辐射和端口特性,因此电流失真参数可以评估互耦对天线特性的影响。利用偶极子天线间、微带天线间、缝隙天线间的互耦以及偶极子天线与金属棒间的耦合等多种计算实例,展示了电流失真参数的特点。它与散射参数一样,均可描述天线间互耦的强弱和评价去耦结构的性能,但侧重点不同。散射参数侧重于互耦对天线端口的作用,而电流失真参数侧重于互耦对天线整体电流的影响。在某些情况下,从端口特性看天线互耦较弱,但实际上互耦对天线的影响很大,甚至会导致方向图有大的畸变。这样这些情况下的电流失真参数可更为准确地表征互耦的影响。同时电流失真参数还可以表征天线对非自由空间环境的敏感度。因此电流失真参数可作为散射参数的一种补充,用于天线互耦问题的研究。(2)设计了多种基于场对消方法的去耦结构,重点解决小间距的微带天线间的互耦间题。这些对消型去耦结构能够在天线间施加一种间接耦合场,并使之与原有直接耦合场相对消,从而实现互耦的抑制。设计了一种结构简单的微带线去祸结构。实验结果表明在天线边到边间距仅为0.023λ0时,隔离度改善了16.7 dB～22.8 dB。设计了一种非对称共面条带去耦结构,该结构不仅有效地抑制了紧密摆放微带天线间的互耦,而且解决了去耦结构影响天线辐射性能的间题。还设计了一种含开路槽的金属墙结构,此结构在实现场对消的同时,其所具有的金属墙也可以抑制部分耦合,因此它具有一种混合去耦能力。最后,以微带线去耦结构为例展示了对消型结构可用于多元阵列的去耦。(3)设计了两种基于带阻滤波方法的去耦结构。这两种带阻滤波型去耦结构均能够在微带天线间的耦合路径上进行滤波,可适用于多种间距的天线间的去耦。所设计的半波地槽结构在微带天线间构建了带阻地平面,以滤除地电流的耦合。该结构的带阻特性仅由地槽自身的谐振决定。仿真和测试均表明,该结构能够满足多种天线间距下的去耦要求,并且适量地增加地槽数可以展宽去耦带宽。设计了一种半波地槽的小型化结构一加载过孔墙的阶跃阻抗地槽,该结构有效地缩短了半波地槽的物理长度,同时较之传统阶跃阻抗结构,该种加载结构占用较小的空间,并取得了更好的去耦效果。以上设计的半波地槽及其小型化结构均可方便地用于多元阵列的去耦。(4)提出了一种模式变换去耦方法,并设计了此方法的实现结构。不同于场对消和带阻滤波方法,模式变换方法并不直接阻断微带天线间的耦合,而是将耦合到邻近天线单元上的模式变换为该天线工作模式的正交模式,并且该天线无法有效地工作于此正交模式,从而增强了微带天线间的隔离度。基于此方法,设计了一种微带交指线去耦结构。仿真分析验证了微带交指线结构的模式变换作用。测试表明在天线边到边间距仅为0.07λ0时,隔离度改善了15.2 dB～24.7 dB。另外,该种结构能够方便地实现多元阵列的去耦。在本文工作中,所提出的电流失真参数提供了一种从电流分布角度表征天线互耦的方法,适用于各类互耦问题的研究,其中包括了天线间的互耦以及天线与非自由空间环境间的耦合；所研究设计的几种类型去耦结构不仅可用于双天线间的去耦,而且还为多天线阵列的隔离度问题提供了解决方案。
[Abstract]:The mutual coupling of antennas has always been an important research content in the field of antenna, which has attracted much attention from researchers. Mutual coupling can not be underestimated for the performance of various wireless communication and detection systems. For example, mutual coupling will deteriorate the transmission isolation, reduce the system capacity, introduce the scanning blind point and influence the design accuracy of the system. The research and exploration of the solution are of great significance and application value. In this paper, two aspects of antenna mutual coupling characterization and decoupling method are studied, and a current distortion parameter based on antenna current distribution characterizing mutual coupling is proposed, and the decoupling structure based on various methods is designed. The main work and research results are as follows: (1) A parameter of current distortion is presented to characterize the mutual coupling of the antenna. This parameter gives the relative difference between the current distribution of the antenna without mutual coupling, thus characterizing the influence of the mutual coupling on the current distribution. It is necessary to study the influence of mutual coupling on the antenna, so it is necessary to study other parameters that characterize mutual coupling. Because the current distribution of the antenna determines its radiation and port characteristics, the current distortion parameters can evaluate the effect of mutual coupling on the antenna characteristics. A variety of calculation examples, such as the coupling between the sub antenna and the metal rod, show the characteristics of the current distortion parameters, which can describe the strength of the mutual coupling between the antennas and evaluate the performance of the decoupling structure as the scattering parameters, but the focus is different. The scattering parameters focus on the interaction of the mutual coupling on the antenna ports, and the current distortion parameters focus on mutual coupling to the sky. In some cases, in some cases, the mutual coupling of the antenna is weak, but in fact, the mutual coupling has a great influence on the antenna, and even leads to the large distortion of the direction map. In this case, the current distortion parameters can more accurately characterize the influence of mutual coupling. The sensitivity of the free space environment. Therefore, the current distortion parameters can be used as a supplement to the scattering parameters. (2) a variety of decoupling structures based on field cancellation are designed, focusing on the mutual coupling between microstrip antennas with small spacing. These pairs of decoupling structures can apply a kind of indirect indirection between the antennas. The coupling field is eliminated with the original direct coupling field, and the mutual coupling is suppressed. A simple structure of microstrip mischief is designed. The experimental results show that the isolation degree is improved by 16.7 dB to 22.8 dB. when the edge distance of the antenna is only 0.023 lambda 0, and the structure is not only effective. To suppress the mutual coupling between microstrip antennas and to solve the interlock between the decoupling structure and the radiation performance of the antenna, a metal wall structure with open channels is designed. The structure is eliminated and the metal wall of the structure can suppress the partial coupling. The decoupling structure of the microstrip line shows the decoupling of the canceling structure for multiple arrays. (3) two decoupling structures based on the band resistance filter method are designed. These two band resistance filter decoupling structures can be filtered on the coupling path between microstrip antennas, which can be applied to the decoupling of multiple spaced antennas. The designed half wave is designed. The geosyncline structure is built between the microstrip antennas and the ground plane is constructed to decouple the ground current. The band resistance characteristic of the structure is only determined by the resonance of the geosyncline itself. The simulation and test show that the structure can meet the decoupling requirements under a variety of antenna spacing, and a proper number of geosyncline numbers can be used to widen the decoupling bandwidth. The miniaturized structure of the wave geosyncline loaded the step impedance geosyncline of a perforated wall, which effectively shortened the physical length of the half wave geosyncline and compared with the traditional step impedance structure. This kind of loading structure takes up a small space and achieves better decoupling effect. The above designed semi wave geosyncline and its miniaturized structure can be easily used. (4) a mode transformation decoupling method is proposed, and the realization structure of this method is designed. The method is different from field cancellation and band stop filtering. The mode transformation method does not directly block the coupling between microstrip antennas, but the mode of coupling to the adjacent antenna unit is transformed into the orthogonal mode of the antenna mode. And the antenna can not work effectively in this orthogonal mode, thus enhancing the isolation between microstrip antennas. Based on this method, a microstrip interdigital decoupling structure is designed. The simulation analysis proves the mode transformation of the microstrip interdigital structure. The test shows that the isolation degree is improved by 15.2 d when the edge to side distance of the antenna is only 0.07 lambda 0. In this paper, the current distortion parameters provide a method to characterize the mutual coupling of antennas from the angle of current distribution, which is suitable for the study of various mutual coupling problems, including the mutual coupling between antennas and between the antenna and the non free space environment, in this paper, the current distortion parameters presented in this paper provide a method to characterize the mutual coupling of antennas from the angle of current distribution. Coupling, several types of decoupling structures designed to be designed can be used not only for decoupling between two antennas, but also for the isolation of multiple antenna arrays.

【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TN820

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