VHF 频段漏泄同轴电缆埋地传感器研究

为了获得漏泄同轴电缆作为一种埋地探测传感器的电气特性,研究适用于周界入侵探测系统的漏泄同轴电缆,设计了一种外导体为八字形开槽的漏泄同轴电缆。基于漏泄同轴电缆的理论分析和相关行业标准,利用商业电磁仿真软件Ansoft HFSS,建立了用于计算漏泄同轴电缆传输衰减和耦合损耗等重要电气特性的电磁仿真模型,作为一种工作在VHF 频段的埋地传感器,利用实验数据分析其VHF 频段工作特性,建立了用于分析耦合损耗特性的埋地传感器系统模型,分析了结构尺寸参数对耦合特性的影响,进一步计算了漏泄同轴电缆的多个电气性能参数及其变化规律。仿真结果表明:在VHF 频段,槽口缝隙的长度、倾角会对埋设双缆的接收特性产生影响,槽口越长倾角越大则接收效率越高,作为传感器单元的LCX 对比实验表明仿真与实测的结果具有良好的一致性。

Research on VHF Buried Sensor Using Leaky Coaxial Cable Techniques

To analyze the electrical characters of leaky coaxial cable (LCX) and the coupling characters of buried sensor which consists of two parallel LCX, a kind of LCX that has a zigzag slot external conductor is designed. Based on the theoretical analysis and industry standards of the leaky coaxial cable with the help of Ansoft HFSS, a commercial electromagnetic simulation software, several LCX working in VHF frequency band are introduced and analyzed by LCX wireless sensing techniques. Performance characteristics transmission attenuation, coupling loss and other important electrical characteristics of the cable are analyzed via experimental data, the simulation result indicates that the length and angle of the slot will influence the performance of buried sensor in the VHF band, the longer notch and the greater inclination angle mean higher receiving efficiency. The influence of the structure and dimension parameters on the coupling characteristics is analyzed. The electrical performance parameters of the leaky coaxial cable and its variation regularity are further calculated. The coupling loss in three position models are tested, comparative experiments show that both simulation and measured results are in good agreement and meet the design specifications.