Design of High-Q Metasurfaces Using a Trapped Mode for High-Efficient Energy Harvesting

This paper proposes the design of a high-Q metasurface using a trapped mode to enhance the RF energy harvesting efficiency. The unit cell of the proposed design consists of two rectangular loops separated into four strips. The trapped mode is excited by breaking the symmetricity of the two loops, which enables a sharp resonance with a higher quality factor and strong electromagnetic fields around the metallic patterns. The feasibility of the proposed approach is verified by observing improvement of current and near-field distributions, multipole moments, and time-domain responses. A bias circuit is also designed to switch between ON and OFF states to electrically change symmetricity of the geometry. The results prove that the efficiency of RF energy harvesting can be improved by the proposed metasurface with the trapped mode.