Recent Trends in Ambient RF Energy Harvesting

RF energy harvesting has emerged as a promising solution for powering low-power IoT nodes, wireless sensors, and portable electronics, offering an alternative to conventional batteries. This review provides a concise overview of rectenna-based RF harvesting systems, outlining their operating principles and summarizing recent advancements in wideband, multi-band, flexible, and wearable designs. Developments in rectenna arrays and metasurface-based architectures are also discussed, with emphasis on strategies to enhance harvested power. Key challenges and future research directions are highlighted, focusing on efficiency improvements and scalable integration.