Enhanced Humidity Sensing with Nafion-Based Chipless RFID Resonators

Chipless radio frequency identification (RFID) has recently been the focus of extensive research due to its efficiency and low-cost manufacturing process. In this article, a highly sensitive, rotation-independent chipless RFID sensor is presented that can be deployed for humidity sensing. Different RFID resonators are designed and simulated, and the results are compared. The proposed RFID resonator is based on an electric-field coupled (ELC) structure. Another part of the study is humidity sensing which is introduced by utilizing the dielectric change of Nafion 117, a material that is strongly interactive with water molecules. A comparative evaluation is done with the commonly used resonators. The response of the sensor is simulated for a variation in relative humidity (RH) ranging from 0%-90%. The results exhibit significant potential to be used in humidity-dependent applications.