For the first time, we designed and experimentally showed that electromagnetic -EM- energy harvesting can be obtained with a flexible ultra-thin commercially substrate metasurface. The use of cylindrical metasurface EM harvester would be desirable for ambient EM energy harvesting since it can absorb the EM energy with maximum efficiency. The harvester is fabricated by an 11×11 unit-cell metasurface with a flexible substrate to demonstrate the isotropic harvesting; as a small slice of cylinder. We propose a sub-wavelength - ̴ 0.13λ0- complimentary quad split ring resonator -CQSRR- unit-cell which is loaded with a lump resistor mounted on the metal-backed substrate. The full-wave simulation shows that the efficiency of the flat metasurface energy harvester with thickness of 0.004λ0 at 5.33 GHz -WiFi- is up to 0.86 for normal radiation. It is 0.72 and 0.62 for 70o oblique angle of incidence from H- and E-plane. The experimental results show that there is a good agreement with the results of full-wave simulation. Due to non-uniform mutual coupling between the cells in the finite array of the fabricated energy harvester and efficiency definition for the central cell as a metric of evaluating the device performance; an effective area for the central cell has been obtained experimentally which is 4.3 times greater than the physical area of a single unit-cell in an infinite array.

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