| 摘要 |
PROBLEM TO BE SOLVED: To provide a power radiation level in a communication area, equal to or more than a conventional case, and to reduce interference with an adjacent lane by making radiation directivity in the direction of traveling vehicle into a pencil form and making radiation directivity in the direction of road width into a sector form. SOLUTION: A transmission antenna or a reception antenna is constituted by providing plural dipole antennas 13. A road machine is formed by the transmission antenna, the reception antenna and a transmitter. Antenna beams are formed by exciting the dipole antennas 13 by specified amplitude and phase. For forming the beams of complicated forms, it is necessary to increase the number of elements. Then, the number of the radiation elements in the direction of road width is increased, only the desired travel lane is radiated and the radiation directivity in the sector form with less interference to the adjacent lane is provided. The number of the radiation elements in the direction of vehicle travel is made smaller than the number of the radiation elements in the direction of road width, and radiation directivity in the communication area on the travel lane is set to be the radiation directivity of the pencil form.
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