矿井不规则巷道电磁波传播特性研究

Because of the particularity and complexity of the mine environment, the ground mature mobile communication system can't directly applied in underground coal mine. In order to construct the new mine mobile communication system and promote of the safety production in coal mine, it is essential and urgent to further research mine wireless theory and technology combining the actual underground coal mine environment. Previous studies mainly confined to the electromagnetic wave propagation of the ideal straight tunnels, such as rectangular and circular; taking the methods to simplify and approximate arch, semicircle arch, trapezoidal and other abnormal section tunnels, and bend, branch and other irregular tunnels, the model is relatively simple, and the calculation is not precise enough. This project will introduce the concept of rays density normalized, improve the classic rays optical method, construct the electromagnetic wave propagation models of irregular tunnels, research the electromagnetic wave propagation characteristics of bend and branch tunnels, electromagnetic signals attenuation vary with the factors of frequency, transmission distance, section size, antenna polarization mode, bend curvature radius, and wireless channel characteristics. Equivalent analysis method will be perfected and applied to research the abnormal section tunnels with the theory and models of circular and rectangular tunnels. Studying the electromagnetic wave propagation characteristics of irregular mine tunnels has great significance in promoting the development of mine wireless transmission theory and guiding the design of the mine mobile communication system.

由于煤矿井下环境的特殊性和复杂性，地面成熟的移动通信系统无法直接应用于煤矿井下通信。为构建新型矿井移动通信系统，促进煤矿安全生产，结合煤矿井下实际环境，进一步深入研究矿井无线传输理论和技术是必要而且迫切的。前人针对矩形、圆形等理想直巷道电磁波传播做了大量研究，对拱形、半圆拱形、梯形等异型截面巷道以及弯曲、分支等不规则巷道，采取近似、简化的方法，建立的模型比较简单，计算结果不够精确。本项目将引入射线密度归一化概念，改进经典射线光学法，建立不规则巷道电磁波传播模型，研究巷道弯曲、分支巷道电磁波信号衰减随传播频率、传播距离、截面尺寸、天线极化方式、弯曲巷道曲率半径等因素变化的特性以及不规则巷道无线信道特性；完善等效分析方法，利用圆形巷道或矩形巷道模型分析异型截面巷道电磁波传播特性。研究矿井不规则巷道电磁波传播特性，对促进矿井无线传输理论的发展，指导矿井移动通信系统的设计和研究具有十分重要的意义。

针对矿井巷道电磁波传播的特殊性，本项目研究了巷道电磁波混合模型的分界点问题，运用等效分析法研究异型巷道电磁波传播特性。通过研究得到以下结论：（1）巷道电磁波近场区采用自由空间模型、远场区采用波导模型，由此可以建立混合传播模型；（2）根据两种模型的场强值确定两种区域的分界点；（3）随巷道截面尺寸的增大和传播频率的增高，分界点与发射点之间的距离增大，分界点处波导模型所需考虑的模式增加；（4）结合不同截面形状巷道，定义了形状因子的概念；（5）巷道形状因子与巷道截面积的大小和电磁波的频率无关，与围岩电参数有关，随着围岩电参数的增大，巷道形状因子也增大；（6）矩形，椭圆形，拱形巷道中围岩介电常数相同时，电磁波水平极化衰减最小的形状因子也相同；（7）在面积和形状因子相同的情况下，拱形巷道电磁波的衰减最大，椭圆形巷道电磁波的衰减最小。上述研究成果对促进矿井无线传输理论的发展，指导矿井移动通信系统的设计有一定的意义。