矿井巷道中导行电磁波的传输特性分析

Analysis of transmission characteristic of guided electromagnetic waves in mine tunnels

文章采用表面阻抗法推导了矿井巷道中导行电磁波的单线波模和双线波模特征方程,根据镜像法求得了巷道中任一点的合成场分布,求解了圆形巷道中的单线波模衰减常数,并对分析结果进行了数值分析。仿真结果表明:导线的存在使低频单线波模的传输衰减随频率的增加而增大,当导线靠近巷道壁时,趋肤效应越严重,衰减越严重;当导线悬挂于巷道中央时,衰减变小。双线波模的场主要集中在双线之间和周围很小的区域,受双线之间的间距影响要强于线壁之间间距的影响,而单线波模的衰减是线壁间距越小,衰减越大。

The equations of both monofilar mode and bifilar mode of guided electromagnetic waves in mine tunnels are presented by using surface impedance method,and the distribution of synthesized electromagnetic field of a casual point in tunnels is given by utilizing image approach.The attenuation constant of monofilar mode in a circular tunnel is solved.The numerical simulation is carried out and the results show that the transmission attenuation of low frequency monofilar mode increases with the increasing frequency due to the existence of the cable.The skin effect and attenuation are more serious as the cable is closer to the tunnel wall,and the attenuation decreases when the cable is located at the center of tunnel.The field of bifilar mode concentrates in the space between double cable and surrounding area,and it is more affected by the space between double cable than by the space between double cable and tunnel wall,while the attenuation of monofilar mode increases with the decreasing space between the cable and tunnel wall.