Current Status and Future Prospects in Sustainable Wireless Energy Transfer: A Comprehensive Review

Abstract

Wireless power transfer (WPT) and energy harvesting (EH) is a fundamental technology for supplying energy wireless powered devices which operate continuously without battery assistance. This survey summarizes RF-based WPT and ambient energy harvesting (EH) methods in the field of IoT sensor network. This paper reviews recent advances in hardware, including small antennas, low-power rectifiers, and metamaterial-analogous concepts that improve the reception and conversion of power. Near-field methods, including inductive and capacitive coupling will be compared to far-field RF and microwave techniques, where the former are limited to short distances whereas radiative techniques may allow for long-distance metrics at the expense of higher attenuation losses. Moreover, the paper sheds light on network-level approaches like Simultaneous Wireless Information and Power Transfer (SWIPT) and efficient scheduling. Despite these advancements, ambient RF power densities are quite low, and system integrations are still complex, which limits the maximum power that can be realized using this technology. This work reviews the trends in the background, their associated challenges, and the roadmap to achieve real self-powered IoT systems.