RFID vapor sensor: Beyond identification

Since RFID is wireless technology, it enables the identification from a distance, depending upon the read range of the tag. There is a vast requirement of RFID technology in security, military, health-care, airline, library, sports, farming and other applications, not only for identification but as a sensor to monitor different parameters related to these fields. RFID based environmental sensor can be designed with the integration of sensing material in a microstrip antenna. The properties of the sensing material are responsible for converting a passive tag as a sensor. Here, RFID based passive chemical vapor sensor is presented doped with the conducting polymer. A sensitive Polystyrene Sulfonate is used as sensing material to integrate in H-shaped slot of PIFA like tag. The designed tag working at 870 MHz is characterized by turn-on and back-scattered power measurements. The experimental results are also presented by considering known and unknown percentage of water vapor and the moisture levels.