弯曲矩形隧道电磁波衰减特性

Attenuation Characteristic of Guided EM Waves in Curved Rectangular Mine Tunnel

实际矿井隧道有许多弯曲段 ,为实现全矿井的无线移动通信 ,需要知道在弯曲隧道中电磁波的传播特性 .针对简化了的弯曲矩形隧道模型 ,在柱坐标系下推导出了弯曲矩形隧道中的电磁波模方程 ,利用 Airy函数与柱函数之间的近似关系式 ,采用抛物线法求解了波模方程 ,从而得到了在不同条件下的波模衰减系数 .由分析可知弯曲隧道的曲率半径越小 ,即拐弯越急 ,电磁波衰减越严重 ;且频率越高 。

There are many bends in mine tunnels, and it is necessary to know wave propagation characteristic in curved tunnels in order to realize wireless mobile communication of a whole mine. The transmission of electromagnetic waves in a curved mine tunnel was analyzed using a simplified model in a cylindrical geometry. The tunnel cross section was assumed to be rectangular. Mode equations were solved, and the computations of the modal characteristics were facilitated by using Airy function approximations of cylindrical functions. The results indicate that the less the curvature of tunnels and the higher the frequency of electromagnetic waves, the more is the attenuation of electromagnetic waves.