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前言实现地铁无线通信的关键在于解决电波在隧道中的传播问题。为此,一般都不采用空间波辐射方式,而是采用波导线导波方式。波导线是一种开放型传输线。它兼有传输线和天线两种功能。导波方式,就是将波导线沿隧道敷设,其末端接匹配负载,始端通过转换器和同轴电缆馈线与固定台相接。这样,当移动台位于波导线附近时,由于波导线和移动台之间相互交换电磁能,从而能够实现固定台和移动台之间的无线通信;而固定台和调度中心之
Preface The key to achieving wireless communication in metro stations is to solve the problem of the propagation of radio waves in tunnels. To this end, generally do not use the space wave radiation, but the use of waveguide guided wave way. Wave wire is an open type transmission line. It combines both transmission line and antenna functions. The guided wave method is to lay the wave conductor along the tunnel and connect the end with the matched load. The beginning end is connected with the fixed station through the converter and the coaxial cable feeder. In this way, when the mobile station is located in the vicinity of the waveguide, the wireless communication between the fixed station and the mobile station can be realized due to the mutual exchange of electromagnetic energy between the waveguide and the mobile station; and the fixed station and the dispatch center