新型高精度二维全向扫描天线的宽带、多波束并行工作方法研究

Aiming to the drawbacks of the current scanning antenna including the limited scanning range, slow scanning rate, and the degenerated gain as the output angle increasing, this project is proposed to achieve scanning antenna based on metamaterials with excellent performance. Via the preliminary research, proposer learns the way to design electric-controlled 2D omnidirectional scanning antenna with high precision, obtains the theoretical value of the minimal scanning angle about 5.7° and the feasible approach to reduce the value further. In this project, the principle and mechanism of broadening the operation bandwidth and realizing multi-beam parallel working are need to be further investigated on the premise that the omnidirectional scanning and the high precision are held. Impacts of configuration and arrangement of the unit cell and the excitation manner on the performance of the scanning antenna would be analyzed and investigated. The design and the fabrication of the scanning antenna and the feed network are put forward. Experiments would be carried out to demonstrate the antenna possessing the capability of broad bandwidth, rapidly, and accurately responded in 2D plane. This would provide a new route to achieve omnidirectional scanning in fields of communication, radar detection and so on.

针对现有扫描透镜天线存在的诸如扫描范围受限、扫描速率慢、增益随出射角衰减等问题，提出基于人工结构材料设计的高性能扫描透镜天线研究方法。通过前期研究，申请人掌握了电控高精度二维全向扫描透镜天线的设计方法，获得了5.7°最小扫描角的理论结果和进一步提高扫描精度的可行方法。本项目拟在此研究成果上，深入研究在保证高精度及全向扫描特性前提下，掌握透镜天线工作频段拓宽和多波束并行工作的理论原理和设计方法。理清单元结构、折射率分布及馈源激励方式等主要参数对透镜天线扫描特性的影响规律。提出扫描透镜天线的加工方案和馈电网络设计方法。通过实验验证该天线辐射特性，实现宽带、快速、精确、灵活多样的二维全向电磁波束扫描，为信息通讯、雷达探测等学科领域提供一种智能扫描天线的新方法和途径。

传统相控阵扫描天线重量和体积不利于集成和移动，基于人工电磁材料的扫描天线虽然可以克服这些缺点，但其本身也存在扫描角度有限、速率慢、增益随辐射角衰减严重等缺陷，不利于普及推广。本项目在前期基础上，经过深入研究，实现提升天线工作带宽和扫描效率的方法。主要研究内容包括：从原理上验证扫描透镜天线实现多波数并行工作方式，提高扫描效率；构建可用于实际加工的扫描透镜单元结构，通过外加偏压调节变容二极管电容值，实现单元结构等效折射率变化满足透镜设计所需范围；设计馈电网络，分析传输特性曲线，实现每个单元结构独立可调；通过调节变容二极管电容值为0.35pF，实现工作频段内单元结构反射率增强，表现出“人工电磁反射板”的效果，为进一步提高天线增益提供方法；调节“人工电磁反射板”位置和排布，实现扫描天线工作频率和增益调节；设置不同组电压排布，实现扫描天线工作频段拓展；分析天线扫描角影响因素，提出获得精细扫描角的方法；分析天线远场辐射图，理论上获得稳定高增益的二维全向扫描；从仿真和测试结果分析得出结论，影响天线增益主要因素是二极管封装电阻，并提出进一步降低天线损耗的方法。获得天线理论指标为：增益相比偶极子天线提高约9.8dB，单组电压排布天线工作频率约200MHz，360°扫描角，扫描过程中最大增益起伏小于3dB。本项研究设计实现宽带、快速、高精度、多波束并行工作的二维全向扫描天线，为信息通讯、雷达探测等学科领域提供一种新方法和途径。另外，研究有机-无机钙钛矿材料特性，以期其优秀光电性能可以用于微波天线设计。