The Novel Flexible Fresnel Lens on PET Substrate

In this paper, the authors present the first design of a Fresnel Zone Lens (FZL) on a flexible dielectric substrate, namely Polyethylene terephthalate (PET), operating at 28 GHz. Notably, the FZL exhibits broadband performance across the range of 25-30 GHz. The far-field radiation patterns of the horn antenna are plotted both without the lens and with the FZL, bent at various central bending angles (θ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</inf> ). The FZL demonstrates stable performance, with the realized gain of the horn antenna decreasing by an average of 0.13 dBi and 0.93 dBi for θ <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</inf> =50° and 120°, respectively. This discovery suggests potential applications in fields such as vehicle communication and biomedical applications, where conformal surfaces are prevalent, enabling efficient wireless power transfer.