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« We’ve devised RFID chips with no electronics ! »

ENGLISH VERSION Hervé Aubert works in research at LAAS, where his team (*) has come up with a new concept for RFID chips using micro-sensors, which manufacturers are already eyeing with interest. With the first « RFID Congress » taking place in Toulouse on 14 – 15 September we take a look at this original idea.

What are the differences between traditional RFID chips and yours ?

We’ve stripped the micro-systems of all their electronics ! Normally, most RFID chips work using a small aerial, a little electronic circuit and so some form of power supply. Our take is totally different. We’ve made silicon-based micro-sensors that change their electromagnetic properties according to the actual physical size of the pressure, temperature, gas concentration, etc. being measured.

We then send quite a high frequency electromagnetic microwave flux from a little radar to the sensor, which sends back an echo whose signature basically depends on it’s electromagnetic state, and thus the physical size of the parameter being measured. This echo is analysed by the reader/detector.

Variations in temperature, pressure or just presence of a gas, can thus be monitored in real time, and this technology also allows carrier identification – object or person – which means they fulfil the original role of RFID chips.

What do these sensors and the detector look like ?

The pressure sensors that we’ve devised have got a silicon membrane which is deformed when a pressure is applied and they’re only a few square millimetres in size, The gas-detection sensors are no bigger than a one centime coin, and the reader that we use is a radar which sends out continuous, modulated waves.

What are the advantages of your approach ?

We can do without the microelectronics and especially the micro power supply system, meaning that the chip becomes a fully passive sensor unit. Compared to traditional RFID’s, the advantages are that our technology lasts longer, costs less, is easier to make … Plus, it performs really well in terms of range, because in the laboratory we have been able to detect our micro-sensors up to 40 metres away.

What applications do you envisage ? Are you working with manufacturers ?

Part of our study has already been financed under the auspices of the SACER project (stand alone communicating sensor networks in embedded systems) supported by the Aeronautics, Space and Embedded systems competitiveness cluster. This programme aims to develop networks of wireless sensors for temperature, pressure, vibration, etc., to be used in the avionics sector, because at present the sensors used are linked by electrical and IT wiring.

We are also part of a joint research programme lead by the French national radioactive waste management agency (ANDRA). This involves putting sensors in the alveoli situated within areas where nuclear waste is stored, whose role will be to detect any abnormal variations in temperature, which could indicate radioactive leakage.

Our research is also supported by the Midi-Pyrénées region under the aegis of the « RF Gaz » project which, as its name suggests, concerns detecting various gases using our technology.

In 2009 we have applied for a patent to protect our inventions, and this has now been extended internationally. And several manufacturers, including some small and medium sized businesses in our region, are ready and waiting to put the technology rapidly onto the market.

Interviewed by Frédéric Dessort, for KwantiK !

Translation : Adrian Pavely

(*) The members of the Micro and nanosystems communications research team at LAAS are : Hervé Aubert, who is also a professor at ENSEEIHT, Patrick Pons and Philippe Ménini, plus three PhD students, Hamida Hallil, Mehdi Jatlaoui and Franck Chébila.