High-Bandwidth Flexible Inkjet-Printed Antenna Design for Microwave Power Transfer Applications

This letter demonstrates an inkjet-printed antenna flexible harvester for microwave wireless power transmission (MWPT). The substrate and radiator are separately based on Polyimide and EGaIn(Eutectic gallium indium alloy, in which the mass fraction of Ga and In are 75.5% and 24.5%, respectively). Based on metal etching, secondary etching is carried out on the substrate to reduce the dielectric constant, the antenna's quality factor has been reduced, altering the coupling of the patch, thereby increasing the antenna's bandwidth. Simulation results indicate that at a working frequency of 5.8GHz, after the etching operation, the bandwidth is 5.19-5.92GHz. Simultaneously, within the bandwidth range, the total efficiency has significantly improved, and there is a notable enhancement in gain within the frequency range of 5.3-5.8 GHz. The measurement results indicate that the antenna has a bandwidth of 5.17-5.83 GHz. The maximum captured power is 35.4 mW at 5.7 GHZ, and it can maintain a captured power of over 22 mW under multi-angle incident waves. Under different conformal curvatures, the antenna can still maintain a captured power of over 28 mW. The results indicate that the antenna can be applied to energy reception under flexible conformal conditions, meeting the requirements of future flexible, wideband energy reception applications. This contributes to the field of wireless power transmission to a certain extent.