| 摘要 |
PROBLEM TO BE SOLVED: To realize stable communication between vehicles without instantaneous interruption and break owning to the drop of reception power by installing plural antennas so that heights from ground differ at the time of installing them in an on-vehicle transmitter/receiver and removing the influence of reception power caused by road reflection as a result. SOLUTION: Transmission signals from the other vehicle are received by the antennas 101 and 102 of a reception vehicle. The heights of them installed in the vehicle differ. When the antennas are installed in a vertical direction, a phase differenceΦbetween a direct wave and a reflected wave in the antennas 101 and 102 approximately becomesΦ=4πHt(Hr+ΔHr)/(λD), where Ht is the height of the transmission antenna, Hr is the height of the reception antenna,λis the wavelength of a carrier and D is vehicular gap. The change in antenna heightΔHr consequently generates the phase differenceΦ. When the phase differenceΦis odd times as much asπ, the phases of the direct wave and the reflected wave, which are reversed in the antenna 101, become in-phase and they are mutually strengthened Then, the attenuation of large reception power is removed.
|
