| 摘要 |
PROBLEM TO BE SOLVED: To provide a road-to-vehicle communication system, its base station, and a directional variable antenna particularly desirable as a base station antenna for the system by which further simple directional control as the base station antenna can be executed and further stable data communication can be realized regardless of distance of a parking slot. SOLUTION: A planar array antenna 110, in which horizontal arrays 111a-111p having a plurality of horizontally arrayed antenna elements 111 are vertically arranged in plural stages, is provided to the base station as the directional variable antenna 11a. Switching elements 112a-112p are provided to respective feeding lines of the horizontal arrays 111a-111p of the planar array antenna 110. A beam width in the vertical direction of a beam emitted from the directional variable antenna 11a is made variable through on/off control of the switching elements 112a-112p. COPYRIGHT: (C)2006,JPO&NCIPI
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