Two Novel Structures of Broadband Wireless Communication for High-speed Flying Train in Vacuum Tube

The high-speed flying train in vacuum tube is a brand new mode of transportation proposed in recent years. Unlike the traditional high-speed railways, the ultra high speed of high-speed flying train results in severe Doppler effect, exerting an adverse impact on the vehicle-to-ground communication. In this paper, two structures are proposed mainly to solve the Doppler effect problem. The purpose of first structure is to control the angle between movement direction and antenna radiation direction as small as possible by helical distribution of directional antennas so as to keep the Doppler shift vary within narrow range. The second structure aims to keep the angle as close to 90° as possible by the helical distribution of slots based on the leakage waveguide. The simulation result shows that both two proposed structures present good performance of reducing the Doppler shift caused by high speed dramatically.