RFID-enabled ultrasensitive wireless sensors utilizing inkjet-printed antennas and carbon nanotubes for gas detection applications

This paper presents, for the first time, the integration of conformal paper-based RFID's with a single walled carbon nanotube (SW-CNT) composite for the development of a chipless RFID-enabled wireless sensor node for toxic gas detection and breathing-gas-content estimation. The electrical performance of the inkjet-printed SWCNT-based ultrasensitive sensor is reported up to 1GHz. The whole module is realized by inkjet-printing on a low-cost "green" paper-based substrate designed to operate in the European UHF RFID band. The electrical conductivity of the SWCNT film changes in the presence of ultra-small quantities of gases like ammonia and nitrogen dioxide, resulting in the variation of the backscattered power level which can be easily detected by the RFID reader to realize reliable early-warning toxic gas detection or breathing monitoring with potentially profound effects on ubiquitous lowcost "green" quality-of-life applications.