Textile-Based Batteryless Moisture Sensor

Abstract

In this paper, we established a new type of passive Ultra-High-Frequency (UHF) Radio Frequency Identification (RFID) technology-based sensor with a referenced readout for moisture. We introduced the sensor system, which consisted of a sensor tag and a reference tag. In a highly moist environment, the sensor tag, which was fabricated by embroidery and 3D printing, permanently changed its shape from flat to curved, which then influenced its wireless performance. By recording the backscattered powers of the sensor tag and the unaffected reference tag, the presence of moisture could be detected. Based on our preliminary results, when the mean value of $Delta$P% was higher than 80%, the sensor system indicated exposure to high moisture environment. Our moisture sensing system can provide cost-effective zero-energy monitoring of moisture exposure for versatile application fields.