基于电磁超介质的探地雷达阵列天线设计及工作机制研究

The traditional Ground Penetrating Radar (GPR) has some disadvantages, such as large volume, low radiating capacity and low detection efficiency and so forth. These disadvantages have restricted GPR's development and made them hard to meet the demands of miniaturization, high precision and high detection efficiency. To solve these problems, we propose a novel GPR antenna array architecture and working mechanism with metamaterials (MMs)-based antenna array in this project. The architecture is implemented by loading MMs into the traditional GPR antenna array. With MMs’ novel electromagnetic properties, antenna array’s performance can be enhanced significantly. Since MMs can control the propagation characteristics of electromagnetic wave, they can enhance antenna array’s radiation efficiency and achieve miniaturization. Firstly, we will study the MMs-based radiating model suited for the GPR antenna array and MMs, which can be used to design the miniaturized antenna array. Secondly, in order to improve the radiation efficiency, we will further study the method to load the MMs-based lens, cavity and isolator in GPR antenna array. Then, we will use the MMs-based antenna array to realize beamforming and scanning on the target area by the electric control. This method is beneficial to improve the detection depth and efficiency. Finally, we will conduct an experiment of MMs-based GPR antenna array with real scenarios. In a word, this project can achieve a compact antenna array and increase the GPR’s detection efficiency. Furthermore, the proposed MMs-based GPR antenna array will provide a new way to achieve GPR systems with higher efficiency and smaller size. It has important theoretical significance and application value.

针对目前探地雷达在天线体积、辐射能力、探测效率等方面的局限性，本项目提出基于电磁超介质的探地雷达阵列天线架构及波束扫描工作机制，以满足未来探地雷达的发展需求。该架构利用电磁超介质的新颖电磁特性来改进阵列天线的性能，兼顾阵列辐射能力和小型化；并利用波束扫描机制来提高阵列探测效率。项目首先研究工作于探地雷达频段的低频超介质，以及加载超介质的新型阵列天线，建立相应的耦合辐射模型，从减小阵元尺寸、降低阵元互耦及收发耦合等方面来实现阵列小型化。接着，针对阵列天线辐射能力受限的问题，加载结构紧凑的超介质聚焦透镜、背腔和隔离器，提高阵列辐射增益及接收信噪比。然后，基于所提出的新型阵列天线架构，研究探测范围和精度可调的快速波束扫描机制，以满足高效率探测的应用需求。最后，开展加载电磁超介质的探地雷达阵列天线的相关应用实验。本项目的研究成果将为提高探地雷达的辐射能力、探测效率及实现小型化提供理论与技术支撑。

项目背景：探地雷达广泛应用于道路病害、燃气泄漏、水利灾害等环境与工程地质灾害的防治，随着探测环境的多变和目标位置的加深，探地雷达在天线体积、辐射能力、探测效率等方面的局限性日益凸显。本项目重点基于电磁超介质的探地雷达阵列天线架构及波束扫描工作机制，以满足未来探地雷达的发展需求，同时推动了三维成像探地雷达研究的发展。.主要研究内容：1. 研究了探地雷达阵列小型化及去隔离，通过选用平面结构的渐变槽天线、辐射片刻蚀梳状结构等方式实现阵列小型化；并设计了平面及立体结构的电磁超介质隔离器，可在天线紧密排布的情况下减小阵列天线的互相耦合。2. 重点研究加载电磁透镜的探地雷达新型天线，电磁透镜包括一般结构透镜、渐变折射率透镜、渐变相位超表面透镜及加载阻抗匹配层的透镜，大幅度提高了天线增益及方向性，最大可在整个工作频段内平均提高天线增益9.56 dB。3. 研究了基于电磁超介质的探地雷达阵列天线的扫描机制，完成了蝶形天线二元阵的波束扫描功能，以及平面八木阵列透镜天线的波束扫描功能，分别可以实现在±30°和±25°内的波束扫描。4. 此外，进行了电磁引流器的设计及其在渐变槽天线的应用研究，最大可提高天线增益约6.0 dB。.主要研究结果：本项目研究并实现了应用于探地雷达的高性能阵列天线及波束扫描等关键技术。结合所研究的关键技术，本项目发表国际SCI期刊论文10篇，申请发明专利3项，授权实用新型专利1项。本项目的研究成果充实了电磁超介质模型，丰富了其在探地雷达天线系统中的应用，为提高探地雷达的辐射能力、探测效率及实现小型化提供理论与技术支撑。