Broadband Omnidirectional Rectenna with Integrated Solar Cell for Hybrid Energy Harvesting

This paper presents a broadband omnidirectional rectenna combined with a solar cell for hybrid energy harvesting, addressing the daytime-only limitation of solar cells via complementary RF energy harvesting. To avoid mutual interaction in integration, the solar cell is placed above the antenna to receive light/EM waves from different directions. A broadband discone antenna ensures omnidirectional RF reception from 1.56 to 6.63 GHz, while a single-stub matching circuit and voltage doubler enable rectifier operation from 1.4 to 3.6 GHz, with over 50% power conversion efficiency at 5 dBm. The measurement demonstrates that the hybrid system can yield 20.25 mW from combined RF/solar power. This broadband hybrid energy harvesting system shows potential for powering sensors throughout the day by integrating two complementary energy sources with minimal interaction.