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Effect of Beam Angle of the Transmitting Antenna on Radio Wave Coverage in the Region Containing Tunnel Entrance

Radio wave coverage in open-confined mixed space along the railway is studied in this paper. The space along the railway can be classified into three kinds of spaces, that are, open space, confined space and the open-confined mixed space. The open-confined mixed space locates between the open space and confined space. In order to reveal the radio wave coverage mechanism in the open-confined mixed space and find out the important influence factors, the influence of antenna gain, antenna position, tunnel cross-section shape, and beam angle on the radio wave coverage in the open-confined mixed space are studied. Considering the complexity of environment, the radio wave coverage is modeled by finite difference time domain method. The simulation results show that the radio wave coverage is sensitive to the beam angle of transmitting antenna. And the variation law of radio wave coverage with the beam angle shows a certain correlation with the transmitting antenna position and tunnel cross-section shape.