用于闭域空间（矿井与隧道等）无线通信系统及泄漏同轴电缆的特性
用于闭域空间（矿井与隧道等）无线通信系统及泄漏同轴电缆的特性研究
摘 要
泄漏同轴电缆以其良好的电波覆盖性能在矿山、地铁、隧道或建筑物等闭域空间内的无线通信中得到了广泛的应用，对其电气特性的研究日益成为研究的热点。本文探讨了矿井无线通信的频率特性和系统模型，提出今后技术发展的方向。以及在研究了井下地质条件和生产环境对通信频率的影响因素基础上,确定了井下无线通信传输的较佳频段,并提供了井下蜂窝通信基站的布置方案。最后就泄漏同轴通信电缆的既能传输电磁波信号,又可发射电磁波信号的独特性能进行了分析;对其特殊性能的应用进行研究.并探讨其应用和发展前景.并且从泄漏同轴电缆(简称漏缆)的结构出发，介绍了漏缆的几何参数和物理参数，然后由结构进行辐射原理的探讨，分析了其辐射模式，并且运用柱面傅里叶变换由外导体上的开槽处的场分布得到漏缆在自由空间的辐射场，进一步分析了存在反射的非自由空间内辐射场的求解，讨论了漏缆的位置对辐射场的影响。然后，提出了泄漏同轴电缆的几个重要的电气特性指标，探讨在设计漏缆的频带、驻波比、祸合损耗、传输衰减等重要指标时的基础理论和相关问题，接着对漏缆的电气特性指标进行了综合设计。最后分别介绍了漏缆在地铁、公路隧道、建筑物等闭域空间中的具体应用，比较了天线辐射和漏缆辐射的覆盖性能差异，提出了利用漏缆实现无线通信
关键词 泄漏电缆；无线通信；辐射场; 频带; 耦合损耗;Abstract
Leak coaxial cable with good radio coverage performance in mining, the MTR, tunnels or buildings closed space within the domain of wireless communication has been widely used, its electrical characteristics of increasingly become a hot spot. This paper explores the mine wireless communication frequency and system model, the future direction of technical development. And the study of the underground geological conditions and the production environment on the frequency communications on the basis of factors, identified underground wireless communications transmission band better, and provided a cellular communications Underground station layout program. Finally leakage coaxial cable transmission of electromagnetic signals can, electromagnetic signals can launch of the unique properties of the analysis; its special properties of research. and explore its applications and development prospects. and leakage from the coaxial cable (cable leakage ) structure, introduced the cable missed the geometric parameters and physical parameters, then the structure of radiation theory, analysis of the radiation pattern and the use of Fourier transform cylindrical outer conductor from the slot on the distribution cable to be leak free space in the radiation field, further analysis of the non-existence of reflection free space within the radiation field solution discussion of the location of cable leakage of radiation field. Then, a leak of several important coaxial cable to the electrical characteristics of indicators, designed to explore the frequency leakage cable, VSWR, coupling loss, attenuation, and other important indicators of the basic theory and related issues, Then the electrical cable leakage characteristic indicators of the overall design. Finally introduced in the MTR missed cable, highway tunnels, buildings and closed space domain specific applications, Comparison of the antenna radiation and radiation leakage cable coverage performance differences, the use of leak cable wireless communication options.
Key words: leaky coaxial cable, wireless communication radiated field, frequency band, coupling loss,
第一章 绪论
1.1矿井及隧道无线通信系统探讨
40 年来, 国内外作了多次井下无线通信试验, 研制了部分矿井无线通信的设备。90 年代以后,随着通信技术的发展,矿井无线通信逐渐进入实用阶段。由于矿井情况复杂,理论研究相当困难,因此矿井中的无线通信主要以实验为基础缓慢发展。试验表明, 在中短波频段, 矿井隧道对电波衰减最大, 通信距离最近。这可以认为是隧道尺寸与波长比拟产生谐振吸收或电波在有限空间内多次反射能量消耗的结果。在超短波,通信距离随着频率升高而增加,电波传播衰减逐渐减小。这种单调的反比变化是由于隧道对更高频率的电波渐呈波导作用引起的,因而传播条件逐渐改善,通信距离加大。在微波频段,随着频率升高衰减变得很小,因此隧道可认为是微波通信的波导型通道。这是由于隧道直径远远大于波长,微波信号在隧道中获得了相对较大的自由传播空间形成的。上述实验表明,隧道断面尺寸决定了截止频率。断面大,截止频率低,通信效果就好;断面小,截止频率高,则必须选择更高的信号频率才能实现井下无线通信。
1.2 矿井隧道无线通信方式
矿井隧道通信的特点是封闭于地下的局部环境中, 与地面通信无相互干扰, 因此可以根据需要进行开发, 但应符合通信的发展,进行统