A simple radio frequency (RF) testing system that can be conveniently built and used for measuring radio propagation in tunnels is introduced. With the proposed testing system, RF power attenuation with distance in a train tunnel was measured at four frequencies (455, 915, 2450, and 5800 MHz) for both horizontal and vertical polarizations. Two analytical modeling methods—the ray tracing and modal methods—are applied to model RF propagation in the tunnel. The theoretical predictions based on both methods are compared to field measurements and find good agreement.

中文翻译：

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隧道环境中无线电传播的建模和测量

介绍了一种简单的射频（RF）测试系统，可以方便地构建并用于测量隧道中的无线电传播。使用建议的测试系统，在水平和垂直极化的四个频率（455、915、2450 和 5800 MHz）下测量了火车隧道中随距离变化的射频功率衰减。两种分析建模方法——射线追踪和模态方法——被应用于模拟隧道中的射频传播。将基于这两种方法的理论预测与现场测量进行了比较，发现了良好的一致性。