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Communication Dans Un Congrès Année : 2011

RFID tags : From Identification to Sensing

Résumé

The design of compatible antennas with the awaited applications in the field of the traceability arises much interest in the academic and industrial sectors. The miniaturized antennas, low cost, relatively broad band, represent at the present time an important issue in the field of UHF RFID technology. In practice, UHF RFID tags have to operate whatever the environment of use. Indeed, whatever the itemwe want to identify or whatever where the label isattached, a same tag (and not different tags families) must be able to be used for economical reasons. The environmental parameters are usually application dependantand a priori unknown at the time of the tag design phase. Unfortunately, they have an extremely important impact on the global RFID system performance and anyway they must be taken into account when designing UHF RFID tag antennas. Indeed, the strong constraints which currently weigh on RFID have a direct impact on the current antennas design methods. For several reasons, the RFID antenna design approach is very specific to this field. One can evoke the impedance matching which iscarried out for none purely resistive loads and this while exploiting only the geometry of the antenna. There is also the fact that we don’t know the support on which the label will be used. From there, the design approaches must also be specific and in order to make it possible to obtain robust tags as regards various environments. Lastly, the economical constraints impose low-size and broad band frequencies of operation at the same time. Investigations in this field are numerous. The final goal is to obtain a “universal” tag, i.e. a tag which is still not realistic at that time. One of the major trends in RFID technology lies in its ability to achieve sensing. Indeed, due to its very largely spread and established standards, the temptation is important to try to re-use this technology so as to add functionalities without significantly changing it. In this case, the RFID can be seen as a standard communication system where other functions (not only the identification one) can be implemented. Indeed, rather than looking for a very robust tag to the surrounding environment which will fit with standard RFID applications, it is possible to make the quite tag sensitive to a physical parameter so as to be able to sense it. Any physical parameters which will modify the chip antenna matching, and thus the modulation of the backscattering signal, can be considered. For instance, it was demonstrated that it is possible to measure or monitor the level of a liquid inside a plastic container or the distance between a tag and a metal plate. The interest of this approach lies in the fact that no significant changes of the RFID system have to be done. Thus one obtains a sensor function associated with a unique ID, the whole resting on a communication system already largely spread and standardised. In order to optimize the tag sensitivity, it is possible to design a specific tag antenna for a specific application according to a given chip. For example, it is possible to tune the tag Delta RCS so as to increase the measurementdynamics of the required physical quantity.The development of approaches based on computer aided design taking into account lot of constraints seems to be the essential tool to put RFID to work. In this communication, we will present different design approaches which are specific to UHF RFID tags including sensing capabilities RFID tags.
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Dates et versions

hal-02895241 , version 1 (09-07-2020)

Identifiants

  • HAL Id : hal-02895241 , version 1

Citer

Etienne Perret, Smail Tedjini. RFID tags : From Identification to Sensing. 11th Mediterranean Microwave Symposium MMS’2011, 2011, Hammamet, Tunisia. ⟨hal-02895241⟩

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