Dual-frequency polarization-insensitive and wide-angle metasurface for electromagnetic energy harvesting

Recently, various metamaterial-based harvesters have been investigated for harvesting electromagnetic energy from the ambient environment. However, they suffer from narrow absorption bandwidths and low energy harvesting efficiency. In this paper, we propose a miniaturized dual-layer metasurface designed for harvesting ambient electromagnetic energy, featuring wide-angle responsivity and polarization-insensitivity. The metasurface comprises two metal rings and two layers of dielectric substrates. The results demonstrate that the harvester functions within the S- and C-bands, resonating at frequencies of 2.98 GHz and 4.32 GHz, respectively. These resonant frequencies induce electric dipole oscillations, facilitating strong absorption of electromagnetic waves. The harvesting efficiency can reach to 92.5 % and 93.4 % at the two frequencies. Moreover, the harvester performance over a wide range of incidence angles and various polarized angles of the incident wave is analyzed. The harvester can be used for harvesting the redundant electromagnetic energy of communications or radars in the future.