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Roadside beacon system with polarized beams

  • US 4,983,984 A
  • Filed: 11/25/1987
  • Issued: 01/08/1991
  • Est. Priority Date: 11/27/1986
  • Status: Expired due to Fees
First Claim
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1. A roadside beacon system comprising a plurality of roadside radio-wave antennas for transmitting signals and installed along roads and a plurality of mobile radio-wave antennas mounted on respective vehicles traveling on said roads for receiving said signals,wherein at least one roadside antenna, at a position where a structure is extended over a road, is mounted on a lower portion of said structure to transmit and receive in a downward direction a radio wave polarized in a widthwise direction of said road, and at least one roadside antenna is installed near said road to transmit and receive a vertically polarized radio wave in an obliquely downward direction, andwherein each mobile antenna mounted on a vehicle transmits and receives a horizontally polarized radio wave in a direction of travel of said vehicle, a vertically polarized radio wave in a direction perpendicular to the direction of travel of said vehicle, and a radio wave polarized in the widthwise direction of said vehicle in an upward direction of said vehicle.

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