Nature-inspired Electro-textile Antennas for Passive UHF RFID

Antennas are usually hidden from sight. However, it is possible to design antennas that look visually appealing and socially accepted, while also have the same wireless performance as traditional antenna designs. Literature shows versatile nature-inspired antennas that have leaves and plants as design models. Most of such antennas are used in wideband, broadband, ultra-wideband, wireless local area networks, as well as 4G and 5G networks. The existing implementations do not employ ultra-high frequency (UHF) radio frequency identification (RFID), which, however, is a versatile technology that has taken a growing role for example in the areas of the Internet of Things, wearables, and e-health. Passive UHF RFID-based communication is challenging due to noisy and unstable signals, which sets high requirements on antenna designs. This paper aims to design and fabricate (from electro-textiles) nature-inspired passive UHF RFID tag antennas and evaluate their wireless performance. Each antenna is made in two sizes, a small and a big version. In wireless evaluation, all the nature-inspired antennas show read ranges and radiation patterns suitable for practical use, while the bigger size antennas perform better than the smaller counterparts in terms of read range. In addition to their traditional wireless functionality, these antennas can also have an ornamental function in clothing and can be designed in such a way that enhances the aesthetics and fashionability of wearables or smart clothing.