A Broadband High-Gain Multi-beam Ambient Millimeter-Wave Energy Harvesting System

The rapid development and proliferation of Millimeter-wave networks have significantly boosted interest in wireless energy harvesting within this band. This paper delineates a novel broadband, high-gain, multibeam ambient millimeter-wave energy harvesting system. The system incorporates a modified Luneburg lens, a dualpolarized ME-dipole rectenna array, and a simple DC combiner to adeptly address the challenges associated with battery charging and replacement within the scope of industrial Internet of Things applications. The system leverages frequency, spatial, and polarization diversity to optimize millimeter-wave energy harvesting. The modified Luneburg lens realizes RF combination and multi-beam characteristics, while a simplified rectifier network allows for efficient energy conversion. The antenna array has twenty-nine antenna elements, each achieving 50 bandwidth covering 24-40 GHz. Beams have a gain of up to 27 dBi, providing 130 degrees of three-dimensional spatial coverage. The rectifier design has been validated for high RF-to-DC efficiency across the operating frequency. Our prototype shows the system can provide an output DC voltage of 3.5 V, an output DC power of 6 dBm, and an RF-to-DC efficiency of about 40% when two transmitters produce a power density of 0.15 mW/cm. © 2023 IEEE