Wideband and Load-Insensitive Metasurface Absorber for Radio Frequency Energy Harvesting

This paper presents a new design of a metasurface absorber for radio frequency (RF) energy harvesting. The proposed absorber has a planar structure composing of 4×4 metamaterial unit cells with an absorption bandwidth spanning a frequency range between 6.7-8.25 GHz. The electrical size of each unit cell is 0.3λ x 0.3λ x 0.07λ at 6.7 GHz. The proposed metasurface absorber demonstrates promising ability to absorb the energy of the incident RF wave with near-unity efficiency under varying resistive loads between 100–500 Ω. Results from full-wave simulation show that the proposed absorber can achieve an absorptivity > 99% within the considered frequency range.