Transparent Antenna with Circularly Polarized Reconfigurability for Wearable Applications

In this work, a dual-band and circularly polarized wearable antenna with polarization reconfigurability and low visual intrusiveness is investigated. The proposed coupled-feed antenna, consisting of optically transparent and flexible materials, operates in 2.45-GHz and 3.5-GHz bands. Diagonal coupling and mutual coupling are simultaneously adopted to achieve circular polarizations at dual frequencies. By manipulating the fluidity of the liquid metal-based feed network, two reconfigurable states, including left-fright-handed circular polarizations, are realized. Besides, the antenna has the compact dimensions of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$48\times 48\times 5.5$</tex> mm 3 (0.39 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\times 0.39\times 0.04\lambda 0^{3},\lambda_{0}$</tex> at 2.45 GHz), making it a good candidate for wearable applications.