Design, Fabrication, and Wireless Evaluation of a Passive 3D-printed Moisture Sensor on a Textile Substrate

This paper introduces the first steps of fabrication and the initial wireless performance evaluation of a passive ultra-high frequency (UHF) radiofrequency identification (RFID)-based moisture sensor on a textile substrate. The sensor antenna was embroidered on a stretchable fabric firstly, and then embedded inside a 3D-printed platform. This 3D-printed sensor material changes its properties permanently, after exposure to a high moisture environment. Thus, the sensor can detect the increased moisture in the environment. Based on our initial results, this information can be clearly read from the changed backscattered signal of the embedded passive RFID tag. The fabricated sensor has an initial peak read range of 6 meters. After being dipped into water for 2 hours, the read range of the sensor has a significant decrease, but it is still readable from 5 meters. Thus, this moisture sensor can be read wirelessly from a convenient distance, when considering practical use of moisture sensors.