高速磁浮列车毫米波车地通信系统要求其车载天线具有小型化、宽频带、圆极化和辐射扇形波束等特点.为更好地满足这些要求,设计一种中心馈电的小型化波导螺旋阵列天线.该天线馈电系统采用同轴波导中心馈电、4路矩形波导并馈的形式,通过改变馈电波导尺寸、耦合探针长度以及末端采用波导同轴转换器等形式,实现了所有单元的等幅馈电;天线单元由低剖面螺旋天线构成,采用顺序旋转技术改善天线的圆极化性能.利用全波电磁仿真软件设计了一款中心频率为38 GHz的28单元波导螺旋阵列天线,并进行了实验测试.测试结果表明:在37～39 GHz频带范围内,天线驻波比小于1.41,增益大于21.7 dB,轴比小于3.6 dB,俯仰面波瓣宽度为4.5°～4.7°,方位面波瓣宽度为29°～29.7°,满足毫米波车地通信系统车载天线的设计需求.

The maglev train is a kind of land transportation vehicle with a running speed of more than 600 km/h. In order to ensure the superior performance of the train during operation, this paper first analyzes the magnetic levitation vehicle-to-ground communication system. The high Doppler effect in high-speed environment leads to an increase in the system error rate. This paper designs a wireless network soft handover mechanism based on TDD system, including intra-partition handover and cross-partition handover, and designs the MAC layer frame structure. Finally, through simulation, it is concluded that the handoff success probability is 99.6% when the speed is 600 km/h, and the distance of the switching overlap area can be set to 264 m.

随着动车组的提速,牵引回流不断增大,导致车体-轴端电位也随之升高,车体-轴端电位的升高可能导致车底传感器判断失灵,危及列车行车安全.基于现场试验测试,通过测试正常工况下试验动车组的车体-轴端电位,分析车体-轴端电位的变化规律.结果表明:车体-轴端电压波形呈正弦工频周期变化,且各车车体-轴端电压波形变化规律基本一致,正常工况最大值为0.31V.所得结论为车体接地系统设计提供了试验基础.