A Preliminary Microwave Frequency Characterization of a Nafion-Based Chipless Sensor for Humidity Monitoring

A low-profile humidity sensor based on a frequency-domain chipless sensing technology is proposed in this study. The chipless microwave sensor is composed by a microstrip resonator gap-coupled with a 50Ω microstrip transmission line and loaded with a Nafion 117 sensitive material layer. The response of the sensor at fixed temperature (25°C) and for a relative humidity (RH) variation in the range 0% - 90% has been simulated and tested in experimental conditions. The preliminary results are promising and pave the way for a future in-depth characterization of the sensor and an analysis of the performance under real-world conditions.