Identification transponder for use when a vehicle passes a given point

摘要

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.