Foldable RF Energy Harvesting System Based on Vertically Layered Metal Electrodes within a Single Sheet of Paper

Abstract

AbstractRadio frequency energy harvesting (RFEH) systems have emerged as a critical component for powering devices and replacing traditional batteries, with paper being one of the most promising substrates for use in flexible RFEH systems. However, previous paper‐based electronics with optimized porosity, surface roughness, and hygroscopicity still face limitations in terms of the development of integrated foldable RFEH systems within a single sheet of paper. In the present study, a novel wax‐printing control and water‐based solution process are used to realize an integrated foldable RFEH system within a single sheet of paper. The proposed paper‐based device includes vertically layered foldable metal electrodes, a via‐hole, and stable conductive patterns with a sheet resistance of less than 1 Ω sq−1. The proposed RFEH system exhibits an RF/DC conversion efficiency of 60% and an operating voltage of 2.1 V in 100 s at a distance of 50 mm and a transmitted power of 50 mW. The integrated RFEH system also demonstrates stable foldability, with RFEH performance maintained up to a folding angle of 150°. The single‐sheet paper‐based RFEH system thus has the potential for use in practical applications associated with the remote powering of wearable and Internet‐of‐Things devices and in paper electronics.