The Effects of Added Clothing Layers on the Performance of Wearable Electro-Textile UHF RFID Tags

In this paper, we study the effects of added clothing layers on the performance of wearable electro-textile passive UHF RFID tags. The electro-textile tag antennas were ironed on the upper back of cotton T-shirts with hot-melt glue and coated with a stretchable protective encapsulant. The wireless performance of the tags was evaluated on-body in office conditions. We tested the effects of wearing two types of winter coats on top of the T-shirts. Based on our measurement results, adding a thick coat on top of the T-shirt does not stop the tag from working but reduces the peak read range from 7 meters to 5 meters. The fabricated electro-textile tags remained readable from distances of 2-5 meters, throughout the global UHF RFID frequency band, even when a thick winter coat was worn on top of the T-shirt.