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本文用一致性几何绕射理论（简称ＵＴＤ），预测了频率为９００ＭＨｚ、１８００ＭＨｚ的窄带和宽带天线电波在隧道中的传播特性，并讨论了隧道的分支、弯曲障碍物对传播特性的影响．其中，窄带和宽带传播特性是分别在空域和时域中研究的。结果表明：在空直隧道中，不同边界条件对窄带信号具有各不相同的传播衰减率；宽带信号具有宽的相关带宽。在弯曲和有分支空隧道中传播衰减较高。在有车辆等障碍物的隧道中接收信号具有宽的相关带宽。在弯曲和有分支空隧道中传播衰减较高。在有车辆等障碍物的隧道中接收信号会有较大起伏、较长的均方根延迟和较高的附加损耗。理论计算结果与实测值非常相符。
In this paper, the propagation characteristics of narrowband and broadband antenna with frequency of 900MHz and 1800MHz in tunnel are predicted by the theory of conformal geometry diffraction (UTD), and the influences of tunnel branches and bending obstacles on the propagation characteristics are discussed. Among them, the narrowband and broadband propagation characteristics are studied in airspace and time domain respectively. The results show that the different boundary conditions have different propagation attenuation rates for the narrowband signals in the air-to-empty tunnel. The wideband signals have a wide correlation bandwidth. In bending and branches of the tunnel propagation attenuation is higher. In a tunnel with obstacles such as a vehicle, the received signal has a wide correlation bandwidth. In bending and branches of the tunnel propagation attenuation is higher. Receiving signals in tunnels with obstacles such as vehicles can have large fluctuations, longer root mean square delays, and higher additional losses. The theoretical calculation results are in good agreement with the measured values.