Identification transponder for use when a vehicle passes a given point
First Claim
1. An identification transponder for use when a vehicle passes a given point, the transponder being constituted by a rectangular waveguide having a large face along a waveguide axis WW'"'"', said large face including regularly spaced-apart longitudinal slots along one of its longitudinal edges and having longitudinal axes extending substantially parallel to said waveguide axis and slot pairs, each slot pair constituted by two slots having axes extending perpendicularly to said waveguide axis and centered on said waveguide axis, each of said pairs being adjacent a longitudinal slot, with the pairs being disposed along said waveguide axis at a pitch of one pair for every n longitudinal slots, and with the presence of a pair corresponding to a bit of value 1 and the absence of the pair corresponding to a bit of value 0, the longitudinal slots successively receiving radiation of polarization Ey perpendicular to said waveguide axis, said radiation including a low frequency F1 and a high frequency F2, the longitudinal slots re-emitting radiation of polarization Ey at said high frequency F2, and said pairs reemitting radiation of polarization Ez parallel to said waveguide axis at said low frequency F1, said transponder being a passive transponder having no power supply.
1 Assignment
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Accused Products
Abstract
The transponder is constituted by a waveguide (1) having a large face (2) including longitudinal slots (3) and pairs of slots distributed along the axis (WW'"'"') of the large face at one pair per n longitudinal slots. Each pair is constituted by two transverse slots (4, 4'"'"') situated facing a longitudinal slot. The presence of a pair corresponds to a one value bit and the absence of a pair corresponds to a zero value bit. The longitudinal slots receive radiation from a transmit antenna (A1) including a low frequency and a high frequency. They radiate to a first receive antenna (A2) using radiation at the high frequency. The pairs radiate to a second receive antenna (A3) using radiation at the low frequency. The antennas are fixed relative to one another and they move relative to the transponder.
21 Citations
8 Claims
- 1. An identification transponder for use when a vehicle passes a given point, the transponder being constituted by a rectangular waveguide having a large face along a waveguide axis WW'"'"', said large face including regularly spaced-apart longitudinal slots along one of its longitudinal edges and having longitudinal axes extending substantially parallel to said waveguide axis and slot pairs, each slot pair constituted by two slots having axes extending perpendicularly to said waveguide axis and centered on said waveguide axis, each of said pairs being adjacent a longitudinal slot, with the pairs being disposed along said waveguide axis at a pitch of one pair for every n longitudinal slots, and with the presence of a pair corresponding to a bit of value 1 and the absence of the pair corresponding to a bit of value 0, the longitudinal slots successively receiving radiation of polarization Ey perpendicular to said waveguide axis, said radiation including a low frequency F1 and a high frequency F2, the longitudinal slots re-emitting radiation of polarization Ey at said high frequency F2, and said pairs reemitting radiation of polarization Ez parallel to said waveguide axis at said low frequency F1, said transponder being a passive transponder having no power supply.
Specification