双通带独立可调微带滤波器的设计

发布时间：2018-02-28 09:50

本文关键词： 微带滤波器可调谐双频段变容二极管　出处：《华中科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前无线通信领域飞速发展,多种通信标准共存,这就要求通信设备朝着多频化方向发展,特别地,频率可调谐的多频微波滤波器能根据实际需要调谐到所需的频段,单个多频可调滤波器就可以工作在更多的通信信道,减少了通信设备中的滤波器数量,减小了设备整体的体积和复杂性,因而受到了越来越多的关注。本文分别重点研究了2种微带型谐振器结构及其谐振特性,并通过在它们两端加载变容二极管制作了两款双通带独立可调谐的微带滤波器。主要内容如下:一、介绍了电调谐滤波器的耦合结构设计方法,通过探究滤波器的外部品质因数和耦合系数,确定结构尺寸的初值。二、讨论了一种新型的非对称的λ/4谐振器对及其谐振特性,非对称的λ/4谐振器对具有两个相互独立的谐振频率,利用它设计制作一款双通带独立可调的滤波器,最后的测试结果是第一通带的中心频率在0.88GHz-1.12GHz范围调谐,3dB的相对带宽在5.1%-6.4%范围内变化。第二通带的中心频率在1.5GHz-1.81GHz范围调谐,3dB的相对带宽在5.4%-6.4%范围内变化。三、研究了中间短路支节加载型谐振器结构及其奇偶模谐振特性。研究发现当中间短路支节的长度很小时,奇偶模频率近似相等,相互耦合形成单一谐振频率。将两个尺寸不同的中间短路支节加载谐振器用相同的输入输出馈线馈电,可以很方便的引入源与负载耦合,并在通带两端产生传输零点,在此基础上设计一款带外抑制良好的双通带独立可调的滤波器,实物测试结果如下:第一通带的中心频率在0.81GHz-0.95GHz范围调谐,3dB的相对带宽在4.2%-5%范围内变化。第二通带的中心频率在1.51GHz-1.79GHz范围调谐,3dB的相对带宽在6.8%-8%范围内变化。在调谐过程中,通带两端的传输零点随中心频率同步变化。在上述设计基础上,分别在输入输出馈线引入不同大小的DGS结构,成功抑制滤波器的高次模频率,同时引入的DGS结构对双通带性能的影响不大。
[Abstract]:At present, with the rapid development of wireless communication field and the coexistence of many communication standards, communication equipment is required to develop in the direction of multi-frequency. In particular, the frequency tunable multi-frequency microwave filter can be tuned to the required frequency band according to the actual needs. A single multi-frequency tunable filter can work in more communication channels, reducing the number of filters in the communication device and reducing the overall volume and complexity of the device. Therefore, more and more attention has been paid to it. In this paper, two kinds of microstrip resonator structures and their resonant characteristics are studied. Two microstrip filters with independent tunable double pass band are fabricated by loading varactor diodes at both ends. The main contents are as follows: first, the coupling structure design method of electrically tuned filter is introduced. By exploring the external quality factor and coupling coefficient of the filter, the initial value of the structure size is determined. Secondly, a new type of asymmetric 位 / 4 resonator pair and its resonance characteristics are discussed. The asymmetrical 位 / 4 resonator pair has two independent resonant frequencies, which are used to design and fabricate a double-pass band independently adjustable filter. The results show that the center frequency of the first pass band varies in the range of 0.88 GHz to 1.12 GHz, and the relative bandwidth of the tunable band varies from 5.1% to 6.4%. The center frequency of the second pass band varies in the range of 1.5 GHz to 1.81 GHz, and the relative bandwidth of the tunable band varies in the range of 5.4-6.4%. The structure and odd-even mode resonance characteristics of the intermediate short-circuit branch loaded resonator are studied. It is found that when the length of the intermediate short-circuit branch is very small, the odd-even mode frequency is approximately equal. Mutual coupling forms a single resonant frequency. The loading resonator with two intermediate short circuit branches of different sizes can be fed with the same input and output feeders, which can be easily introduced into the source and coupled with the load, and can transmit 00:00 at both ends of the passband. On this basis, a double-pass band independent tunable filter with good out-of-band suppression is designed. The results are as follows: the center frequency of the first pass band varies in the range of 0.81GHz to 0.95GHz and the relative bandwidth of 3dB varies in the range of 4.2% -5%. The center frequency of the second pass band varies in the range of 1.51GHz to 1.79GHz, and the relative bandwidth of 3dB varies in the range of 6.8-8%. The 00:00 transmission at both ends of the passband changes synchronously with the central frequency. On the basis of the above design, different sizes of DGS structures are introduced into the input and output feeders respectively, and the high order mode frequency of the filter is successfully suppressed. At the same time, the DGS structure introduced has little effect on the performance of double pass band.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN713

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