RFID tags made of plastics electronics offer specific advantages over silicon (Si)-based identification devices. They can be affixed to curved packaging, incorporated seamlessly in every-day objects and accommodate inexpensive manufacturing. Typical applications include item-level identification, smart food packaging, brand protection and badge security. RFID tags need to be scanned by a dedicated RFID reader which is typically within two centimeters of the tag.

To fully exploit the benefits of plastic electronics, the antenna in both the tag and the reader should be flexible as well. Screen-printed antennas have already been successfully implemented on top of RFID tags, but the read-out systems typically use rigid PCB-based antennas. This is mainly due to a poor resistance and Q-factor of the printed antenna.

Imec, Quad Industries and Agfa have, for the first time, integrated a screen-printed antenna in both the RFID tag and the read-out system. This allows for an optimal integration of both devices on a variety of surfaces. The antennas have been screen-printed by Quad Industries, using printing inks from Agfa.

The partners have demonstrated the new technology in a badge security application. The access badge combines the credit-card size printed antenna with a plastic 12-bit RFID chip, integrated on a flexible plastic substrate. The RFID tag is manufactured in imec’s metal-oxide thin-film transistor (TFT) technology. This technology uses large-area manufacturing processes that allow for inexpensive production in large quantities. The 12-bit RFID developed for this demonstration contains 438 TFTs.

The read-out system contains innovative printed functionality at different levels. Firstly, an RFID read-out antenna is screen-printed on a plastic film, allowing optimal integration on flat, curved or even 3D shaped reader surfaces. Secondly, between the cover lens and the display, a fully printed touchscreen interface with numerical keypad has been added to allow users without a badge to access the building by entering a numerical code. The printed touchscreen was printed using highly transparent screen-printed inks.

The prototype system is demonstrated at the SIM User Forum in Antwerp, Belgium. The work on printed conductive structures is carried out as part of the Flemish Met@link project. The work on transparent touch screens is carried out by Quad Industries under the framework of the European project INREP which received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement n° 641864. The work on flexible RFID technologies is performed in Holst Centre, an open innovation initiative set up by imec and TNO.