Impact of Moisture and Washing on the Performance of Embroidered UHF RFID Tags

Antennas can be seamlessly integrated into clothing by means of embroidery with conductive thread. In the real-life applications, wearable antennas are exposed to various environmental conditions. We studied the impact of moisture and washing on the performance of fully functional RFID tags based on embroidered antennas. The moisture absorbed in the tag structure can cause a temporary reduction in the tag read range. Repeated washing of the tag resulted in permanent reduction, which accumulated over the wash repetitions. Overall, the results indicated that protective coating is needed for sustained operation. Flexible, durable, and hydrophopic polymers, such as polydimethylsiloxane (PDMS), and polymer-ceramic composites are prominent candidates in terms of mechanical and electromagnetic properties.