His long run of successes was made possible thanks to a characterization method he developed at the lab using the principle of reflectometry and resonance elements. The result of this development is the creation of cheap, chipless ID tags that can be printed and recycled. Unlike barcodes, these tags can be read through opaque objects or from a distance. It’s also possible to implement new functionalities that couldn’t be used with barcodes. Finally, as this technology doesn’t use microchips or antennas, the printed tags are much cheaper than traditional RFID tags.
The only difference between chipless RFID and barcodes is their form and their use of conductive ink for printing. Each tag, which can be printed separately or directly onto a product, has a unique electromagnetic signature that provides specific information about the product. “Conductive ink interacts with the wave that is directed at the tag. The information in the signature sends back a specific wave that is received by the tag reader,” explains Etienne Perret. An important part of the process has been to create a method that enables the sizing and printing of tags according to the required information.
In addition to being cheap and easy to scan, these tags can be re-printed, which is quite different from barcodes. “This functionality is probably the most sought after one for printed paper tags.”
The tags can also be used as receptors, in particular for humidity or temperature. “You simply have to add a material to the ink that will be sensitive to humidity, which will then modify the wave in real-time, and therefore change the electromagnetic signature picked up by the tag reader.” Etienne Perret and his team have also used this technology to recognize movements, which means the paper tags could be used as an interface between a user and a machine, much like a remote control or joystick. “The only difference is that this version will require no electronic chips and will simply be printed like a barcode. By printing on packaging they offer opportunities for new functionalities and a simplicity of implementation.”