三叉树弧形分形偶极子天线的设计与实现

发布时间：2018-07-10 10:22

本文选题：标签天线 + 分形天线　；参考：《江西理工大学》2017年硕士论文

【摘要】：在RFID通信技术快速发展的今天,对系统中的标签和阅读器的精度要求越高,并且随着制造业能力的不断提高,对芯片中的硬件集成度也更高,这就要求设计出能够满足小型化的天线。本文通过对分形理论的理解,以及其在天线设计中所具有的特性进行分析之后,介绍了二叉树分形阅读器天线、矩形分形标签天线、树状结构分形天线等天线的情况,并在二叉树弧形分形结构的基础上设计了三叉树弧形分形结构的天线。所做的工作、创新点以及实现的结果主要有以下几点:(1)采用HFSS软件对三叉树弧形天线进行设计,首先设置驱动模式求解,再添加设计过程中所需要的变量,接下来对天线的结构进行建模,并且设置激励、辐射边界条件、2.45GHz工作频率以及扫频。设置完成之后,对天线进行仿真,并且对仿真结果进行分析是否满足天线特性参数的要求。此外对天线的巴伦结构、振子结构以及阻抗匹配结构的参数分别进行优化分析,设计出一个性能更好的三叉树弧形分形天线。(2)该天线主要是将二叉树的结构转为三叉树的结构,并且将三叉树中每个分支的弧形结构由90度增至180度,这两种结构相互结合,相对增加了贴片天线的面积,能够在一定程度上加强天线的辐射特性。利用这种特殊的结构,能够实现在同等面积的情况下,增加天线振子的长度,在一定程度上减小天线的尺寸。(3)所设计的三叉树弧形结构的天线采用采用相对介电常数4.4r?(28),介质损耗角正切tan?(28)0.035的环氧玻璃板为介质基片,利用简单的微带巴伦结构进行馈电,通过平行双线结构实现更优的阻抗匹配。软件HFSS电磁性能仿真分析结果表明,天线的谐振中心频率为2.45GHz,在中心频率出的S11参数的值为-36dB,阻抗匹配效果比较理想,在S11小于-10dB的频率范围为2.28GHz到2.49GHz,带宽为210MHz,相对带宽为8.5%,增益的大小为1.49dBi。对该天线进行实物加工与测试,它的输入反射系数S11和方向图实测结果与软件仿真非常吻合,天线的尺寸有所降低,满足天线小型化的要求,在未来RFID领域有更广阔的应用前景。
[Abstract]:With the rapid development of RFID communication technology, the higher the accuracy of tags and readers in the system, and with the continuous improvement of manufacturing capabilities, the higher the integration of the hardware in the chip. This requires the design of an antenna that can be miniaturized. Based on the understanding of fractal theory and its characteristics in antenna design, this paper introduces the antenna of binary tree fractal reader antenna, rectangular fractal tag antenna, tree structure fractal antenna and so on. Based on the arc fractal structure of binary tree, the antenna with arc fractal structure is designed. The main results of the work, innovation and implementation are as follows: (1) the tri-tree arc antenna is designed with HFSS software. First, the driving mode is set up, and then the variables needed in the design process are added. Then the structure of the antenna is modeled, and the excitation is set up, the operating frequency of 2.45GHz and the sweep frequency are obtained under the radiation boundary condition. After the setup is completed, the antenna is simulated, and the simulation results are analyzed whether it meets the requirements of antenna characteristic parameters. In addition, the parameters of the Barren structure, the dipole structure and the impedance matching structure of the antenna are optimized, and a better performance tri-tree arc fractal antenna is designed. (2) the structure of the binary tree is mainly changed into the structure of the tri-tree. The arc structure of each branch of the tree is increased from 90 degrees to 180 degrees. The combination of the two structures increases the area of the patch antenna and enhances the radiation characteristics of the antenna to a certain extent. With this special structure, the length of the antenna dipole can be increased under the same area. To some extent, the size of the antenna is reduced. (3) the designed tri-tree arc antenna is fed by a simple microstrip Barren structure with a relative dielectric constant of 4.4 r? (28) and an epoxy glass plate with dielectric loss angle tangent tan-( 28) 0.035. Better impedance matching is realized by parallel two-wire structure. The simulation results of the electromagnetic performance of HFSS show that the resonant center frequency of the antenna is 2.45 GHz, and the S11 parameter at the central frequency is -36 dB, and the impedance matching effect is satisfactory. The frequency range of S11 less than -10dB is 2.28GHz to 2.49GHz, the bandwidth is 210MHz, the relative bandwidth is 8.5, the gain is 1.49dBi. The antenna is processed and tested. The measured results of the input reflection coefficient S11 and the pattern are in good agreement with the software simulation. The size of the antenna is reduced to meet the requirement of antenna miniaturization. In the future RFID field has a broader application prospects.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN821.4;TP391.44

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