A fully inkjet-printed chipless RFID gas and temperature sensor on paper

This paper studies the implementation of an RFID chipless sensor based on split ring resonators. It operates in the ISM band at 2.45GHz to detect a change of carbon dioxide, and a variation of temperature. The realization of this passive wireless sensor involves inkjet printing using several ink types so that a device that works can be realized from scratch in a few stages. The substrates used are flexible materials to allow for seamless integration on any object shapes. Several samples have been printed on polyimide substrate 50 μm thick to validate the design with the help of wireless measurements. Finally, another set of samples printed on an ordinary cardboard of 550 μm thickness is realized and measured, and the performance achieved are compared with those of the polyimide based sensors.