铁道隧道中无线电波传播特性的研究

THEORY OF RADIO WAVE PROPAGATION IN RAIL WAY TUNNEL

本文首先给出了隧道中有列车通过时的简化模型——超大尺寸周期加载的不完全矩形波导模型，导出了这种结构中列车的表面阻抗。在此基础上，研究了无线电波在铁路隧道中的传播特性。得到了关于ＴＳＭｑ，ｍｏ模的传输模方程以及ＴＳＭ１，１０的衰减常数。研究结果表明：ＨＥＭ１１模和不同条件下的频率特性，以及车厢中旅客对传播特性的影响。

Research on radio wave propagation in tunnels has important application for mobile and personal communication.This paper first briefly reviews radio wave propagation in empty tunnels,and then concentrates on characterizing radio wave propagation in tunnels loaded with trains.For this purpose,an oversized imperfect periodically loaded rectangular waveguide is proposed,and surface impedance approximation is adopted to formulate the problem.The theoretical results show that HEM 11 and TSM q,mo modes can propagate.Meanwhile,why TSE q,mo modes can not exist is also proved.The closeform propagation constants for those important TSM q,mo modes are obtained.The numerical results for the propagation attenuation of the dominant TSM 1 10 are presented.The influence of passengers on propagation in discussed.