Abstract
In this letter, we propose metasurface absorbers for energy harvesting that work on the principles of destructive interference and phase cancellation. The metasurface is designed by arranging four L-shaped resonant unit cells in a fourfold symmetrical geometry leading to a cross configuration. At resonance frequency, such a geometrical configuration results in destructive interference of the electromagnetic waves emanating from diagonal elements. When used in a reflection mode as a metasurface absorber, the reciprocity theorem necessitates the flow of helicoidal resonant currents that vectorially cancel each other to make the overall metasurface nonradiative that, therefore, produces a null in the backscattering direction. A 90% absorption in simulation is achieved without explicit consideration for a free-space impedance matching or using dissipative substrate. The absorbed RF energy is harvested at 2.25 GHz to practically demonstrate the conversion efficiency of over 55% from microwave to dc.