A novel “green” fully-integrated ultrasensitive RFID-enabled gas sensor utilizing inkjet-printed antennas and carbon nanotubes

In this paper, the integration of a flexible RFID tag with an inkjet-printed Single Walled Carbon Nanotube (SWCNT) film in a chipless sensor node for toxic gas detection was introduced for the first time. The whole module is realized on a "green" low-cost paper substrate. Carbon nanotube composites change their electric properties (e.g. resistance, dielectric properties) in the presence of very small quantities of toxic gases like ammonia and nitrogen oxide. The RFID tag is designed for the 868 MHz UHF band. When NO
_x
gas is present, the resistance of the SWCNT film will drop, resulting in the decrease of the backscattered power which will be detected by the RFID reader to realize the reliable toxic gas detection in a non-invasive way.