A compact chipless RFID tag with environment sensing capability

This paper presents a chipless RFID tag having both identification and sensing capability. It is based on 5 resonant scatterers that behave as signal processing antennas in the band from 2.5 to 7.5 GHz. Only one scatterer is used to monitor a physical parameter variation, while the four others allow identifying the remote sensor with 13 bits. To make a resonator sensitive to the temperature or humidity, a material based on Silicon Nanowire is deposited on the tag surface using a very simple process. The tag needs only one conductive layer so that it can be directly printed on product making by the way a unit cost potentially very low. Measurements done using a bi static radar configuration in the frequency domain validate this new concept.