Commissariat a L'energie Atomique

François Vacherand

Elisabeth Crochon

Olivier Savry

Gilles Delapierre

Thierry Thomas

Sylvain Bacquet

Didier Bloch

A privacy protection method designed to prevent or authorize a communication between a reader and an RFID label situated in an efficiency zone. In the method a) there is permanent detection of possible variation of an ambient magnetic field in one or more frequency bands allocated to the RFID labels, and b) in the event of detection of an instantaneous variation of the local magnetic field and in the absence of inhibition, a parameter value of a magnetic circuit is modified so that the instantaneous value of the local magnetic field is modified.

Contactless privacy protection device

An antenna includes a central loop and four adjacent coplanar eccentric loops. The central loop creates a magnetic field that is essentially perpendicular to the antenna. The centres of gravity of the four eccentric loops are essentially located on the periphery of the central loop and the eccentric loops are supplied in such a way as to predominantly create a rotating field in a plane parallel to the plane of the antenna. The eccentric loops can be associated in pairs of non-adjacent loops in such a way as to generate electromagnetic fields of opposite phases in the respective pair. In this way, the two loops of a pair can be connected such that the same current flows through them in opposite trigonometric directions. A radiofrequency generator can supply first and second excitation signals alternately on two outputs, respectively to the central loop and to the eccentric loops.

Flat plate antenna with a rotating field, comprising a central loop and eccentric loops, and system for identification by radiofrequency

A method and apparatus of information exchange between an interrogator device and a plurality of transponder devices are disclosed. Each of the transponder devices is equipped with a different binary identification code and is located in the magnetic field of the interrogator device, consisting in modifying the duration of the signals and/or the waveform of the signals transmitted by each transponder device according to the ratio between the signal transmitted by the transponder device and the ambient electromagnetic noise.

Method and system of information exchange between an interrogator device and transponder devices that takes into account the level of ambient noise

This invention relates to a secure electronic device comprising:

Secure electronic device

This method of identification between an interrogation system () such as an arch and labels (E) placed on objects to be identified and called upon to pass through the interrogation field () functions by the sending of control signals from the interrogator () to the labels (E) so that the latter transmit their codes. The known interrogation mode in which the codes are supplied bit by bit and the labels responding simultaneously are inhibited in turn so that only one is active and identified at any one time, is preceded by an identification test during which all the labels send their code at one go all at the same time, which allows immediate identification if only one label is present. When a label has been identified, the interrogator () isolates it in order to exchange particular information with it.

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Le Pont de Claix, France

François Vacherand