基于耦合矩阵的滤波天线研究

发布时间：2018-05-13 15:15

本文选题：耦合矩阵 + 滤波天线综合　；参考：《电子科技大学》2016年硕士论文

【摘要】：随着通信信道的越来越拥挤,为了减少信道之间的干扰所以对系统的带外抑制提出了越来越高的要求。由于系统中的非线性器件使得系统的带外抑制变差,在部分系统之中即使在系统中部加入滤波器也难以满足要求,因此需要在前端天线连接处加入滤波器增强带外抑制能力。通常通信系统之中,天线和滤波器被当作独立的器件单独设计,然后简单直接连接在一起。这样的设计方案,容易使整体的通带边缘的选择性恶化,尤其是在天线带宽与天线带宽相当时。因此,对于滤波天线的研究越来越受关注。现今大多数滤波天线设计,主要利用天线替换滤波器的最后一阶谐振器,然后仿真优化得到最终结果。这种设计方式需要耗费大量的时间在电磁仿真中,而优化的最终结果的最优性也缺乏理论的支持。本文利用耦合矩阵理论和滤波器诊断技术综合设计滤波天线,有助于滤波天线的快速设计优化,并且能够判断优化结果与理想目标之间的差异程度。天线和滤波器被当作一个整体来综合设计,整体的性能得到最优化。同时,当确定好天线谐振器后,整个滤波天线的通带性能可以通过调节后面级联的谐振器之间的耦合系数而改善,从而分离辐射方向特性设计和通道选择性设计。本文基于耦合矩阵的滤波天线的滤波天线研究,主要是把耦合矩阵理论应用到滤波天线的综合设计中,为滤波天线的设计提供理论指导。主要的研究内容如下:(1)基于耦合矩阵分析与综合滤波器的理论,研究滤波天线和滤波器综合的异同之处。提出类似于滤波器耦合矩阵综合的一种级联型滤波天线综合方法。具体研究天线谐振特性模型,研究其物理尺寸对天线谐振器的辐射耦合强度与辐射方向性的关系。(2)结合耦合矩阵理论和滤波器诊断技术综合出一款单频带滤波天线。研究类共振器级联型滤波器等效电路进行耦合矩阵参数提取的方法。通过比较提取出的实际物理模型的耦合矩阵与目标耦合矩阵的差异,研究耦合强度与物理尺寸的映射关系,实践基于耦合矩阵参数提取的滤波天线优化方法。(3)对耦合矩阵理论综合设计滤波天线的方法进行延伸扩展,使耦合矩阵理论应用到双频带滤波天线的设计中。利用常见双模谐振器的双频段的响应特点,推演出适合双频带滤波天线的双频辐射单元。分析其在不同谐振频率时谐振器上的电流分布差异,找到能够到相对独立调节两个频段的耦合系数的方法。最终利用基于参数提取的优化,研制出双通带级联型滤波天线。
[Abstract]:As the communication channels become more and more crowded, in order to reduce the interference between channels, the out-of-band suppression of the system is required more and more. Because the nonlinear devices in the system make the out-of-band suppression of the system worse, it is difficult to meet the requirement of adding a filter even in the middle of the system in some systems, so it is necessary to add a filter to the front-end antenna connection to enhance the out-of-band suppression ability. In communication systems, antennas and filters are designed as separate devices and then simply connected directly together. This scheme can easily worsen the selectivity of the overall passband edge, especially when the antenna bandwidth is equal to the antenna bandwidth. Therefore, more and more attention has been paid to the research of filter antenna. Nowadays, most of the filter antennas are designed to replace the last order resonator of the filter by antenna, and then the final results are obtained by simulation and optimization. This design method needs to spend a lot of time in electromagnetic simulation, and the optimality of the final result of optimization is lack of theoretical support. In this paper, the coupling matrix theory and filter diagnosis technique are used to design the filter antenna synthetically, which is helpful to the fast design and optimization of the filter antenna, and can judge the difference between the optimal result and the ideal target. Antennas and filters are designed as a whole, and the overall performance is optimized. At the same time, when the antenna resonator is determined, the passband performance of the whole filter antenna can be improved by adjusting the coupling coefficient between the latter cascaded resonators, so as to separate the radiation direction characteristic design and the channel selectivity design. In this paper, the filter antenna based on coupling matrix is studied, which mainly applies the coupling matrix theory to the integrated design of the filter antenna, and provides theoretical guidance for the design of the filter antenna. The main research contents are as follows: (1) based on the theory of coupling matrix analysis and synthetic filter, the similarities and differences between filter antenna and filter synthesis are studied. A cascade filter antenna synthesis method similar to filter coupling matrix synthesis is proposed. The resonant characteristic model of antenna is studied in detail, and the relationship between physical size and radiation coupling intensity and radiation directivity of antenna resonator is studied. A single band filter antenna is synthesized by combining coupling matrix theory and filter diagnosis technique. The method of extracting coupling matrix parameters by equivalent circuit of cascaded filter of resonator is studied. By comparing the difference between the actual physical model coupling matrix and the target coupling matrix, the mapping relationship between the coupling strength and the physical size is studied. The optimization method of filter antenna based on the parameter extraction of coupling matrix is applied to extend the method of synthetically designing filter antenna based on coupling matrix theory, and the coupling matrix theory is applied to the design of dual-band filter antenna. Based on the response characteristics of common dual-mode resonators, a dual-frequency radiation unit suitable for dual-band filter antenna is derived. The difference of the current distribution on the resonator at different resonant frequencies is analyzed, and a method to adjust the coupling coefficient of the two frequency bands is found. Finally, a double pass band cascade filter antenna is developed by using the parameter extraction optimization.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN713;TN827

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