基于通信的列车控制(CBTC)系统采用漏泄波导作为无线传输媒介,从而实现大容量、高可信度的车地双向通信.本文基于行波天线的理论,定义宽边周期性横缝结构漏泄波导的辐射常数,并给出计算方法,定量分析漏泄波导的辐射能力,通过仿真软件HFSS对其合理性进行验证.将漏泄波导上方33 cm处的电场分布仿真结果与北京地铁亦庄线的实际测试结果进行对比,总结漏泄波导的电场辐射特性.根据对于瑞利信道和漏泄波导的仿真以及两种传播媒介的数据传输速率实验结果,与自由空间相比,漏泄波导能够支持更稳定的信号分布以及数据传速率,更能满足CBTC对数据业务的要求.%Leaky waveguide has been adopted as the wireless propagation medium in some communication based train control (CBTC) systems in order to ensure high-capacity and high-dependability bidirectional train-ground communication. In this paper, on the basis of the theory of travelling wave antenna, the concept of radiation constant of leaky waveguide was defined and the theoretical method to calculate the parameter was proposed. Then rationality of this method was verified by HFSS, which was the industry-standard simulation tool for 3D full-wave electromagnetic field simulation. According to the engineering requirements, the signal strength distributions 33cm above the leaky waveguide were simulated through HFSS and verified by comparison with the field test results of the Beijing Metro Yizhuang Line, and then the characteristics of leaky waveguide were summarized. Both the simulation results of the characteristics of the Rayleigh fading channel and leaky waveguide channel and the data transmission rates in field tests show that leaky waveguide can support more stable signal distributions and data transmission rates in CBTC systems.
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