毫米波双极化微带天线的设计方法研究

发布时间：2018-01-27 14:31

本文关键词： 毫米波双极化微带天线共面波导缝隙耦合遗传算法　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着毫米波技术的不断发展，毫米波系统的应用也越来越广泛。由于双极化的毫米波雷达系统可以充分利用信号的极化信息，，所以双极化雷达系统成为研究热点。本文为满足现代毫米波雷达系统的发展要求，设计了工作于毫米波段的双极化天线。大多数的毫米波系统要求天线具有低剖面、低成本、体积小等特性，所以在本文中针对微带天线展开研究，并设计了两类不同馈电方式的天线单元及阵列：共面波导馈电、缝隙耦合馈电。首先，设计了结构较简单的共面波导馈电双极化天线单元，通过表面电流分布分析了天线隔离度性能差的原因，并针对隔离度问题，本文对天线单元做出改进，加入两条平行微带线及三个小尺寸矩形槽，使单元的端口隔离度达到-20dB。由于交叉极化的问题，再次对天线结构做出改进，提出用短截线换掉平行微带的方法，使得天线的交叉极化达到-20dB。同时，将缺陷接地结构应用到共面波导结构中进行阻抗调配，设计出了符合要求的毫米波天线单元。其次，本文采用缝隙耦合馈电与埋藏式馈电相结合的方式，设计了三个天线单元及一个2×2子阵天线。最先设计的仍然是结构较简单的天线单元，单元的相对带宽为7%。然后分别采用共面寄生贴片和空间平行寄生贴片将天线单元的阻抗带宽展宽为12%和20.53%。采用成对反相馈电技术设计了2×2的子阵天线，天线阵列的相对带宽为6.13%，阻抗带宽小于-10dB范围内隔离度小于-30dB，交叉极化达到-23.6dB，增益为11.5dB，天线的测试结果与仿真结果基本吻合，是各项指标都符合要求的毫米波双极化天线。最后，本文通过VBS脚本将遗传算法与Ansoft HFSS连接起来，采用“开窗”方式及子贴片覆盖技术对结构简单的缝隙耦合馈电天线单元进行了优化设计，将天线的阻抗带宽从2.64GHz展宽到3.99GHz，证明了方法的可行性。
[Abstract]:With the development of millimeter wave technology, the application of millimeter wave system is more and more extensive, because the dual polarization millimeter wave radar system can make full use of the polarization information of the signal. Therefore, dual-polarization radar system has become a research hotspot. In order to meet the requirements of the development of modern millimeter-wave radar system. A dual-polarization antenna working in millimeter band is designed. Most millimeter-wave systems require the antenna to have low profile, low cost and small size, so the microstrip antenna is studied in this paper. Two kinds of antenna elements and arrays with different feeding modes are designed: coplanar waveguide feed and slot coupling feed. Firstly, a simple coplanar waveguide fed dual polarization antenna unit is designed. The reason of the poor isolation is analyzed through the surface current distribution, and the isolation problem is analyzed. In this paper, the antenna element is improved by adding two parallel microstrip lines and three small rectangular grooves, so that the isolation degree of the unit can reach -20dB. due to the problem of cross-polarization, the antenna structure is improved again. A method of replacing parallel microstrip with short cut line is proposed to make the cross-polarization of antenna reach -20 dB. At the same time, the defect grounding structure is applied to the coplanar waveguide structure to adjust the impedance. The millimeter wave antenna unit is designed. Secondly, three antenna elements and a 2 脳 2 subarray antenna are designed by the combination of slot coupling feed and buried feed. The first design is still simple antenna element. The relative bandwidth of the unit is 7. Then the impedance bandwidth of the antenna unit is widened to 12% and 20.53 by using the coplanar parasitic patch and the spatial parallel parasitic patch respectively. X 2 subarray antenna. The relative bandwidth of the antenna array is 6.13, the impedance bandwidth is less than -10dB, the isolation degree is less than -30dB, the cross-polarization is -23.6dB, and the gain is 11.5dB. The test results of the antenna are in good agreement with the simulation results. It is a millimeter-wave dual-polarization antenna which meets the requirements of every index. Finally, the genetic algorithm is connected to Ansoft HFSS by VBS script. The slot coupling feed antenna unit with simple structure is optimized by using "window opening" mode and subpatch coverage technique. The impedance bandwidth of the antenna is broadened from 2.64GHz to 3.99GHz. The feasibility of the method is proved.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN822

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