Polarization angle independent perfect multiband metamaterial absorber and energy harvesting application

A new kind of multi-band metamaterial absorber based on the concentric ring resonators is engineered to be used in various microwave applications including energy harvesting. Numerical investigations are carried out step by step for observation of the effect of each ring resonator. The results reveal that the structure almost perfectly absorbs the electromagnetic wave with polarization angle independency at multiple resonant frequencies in the microwave range. Additionally, the structure is characterized according to the dimension and geometry variations. For the harvesting application, three different efficiencies are suggested, discussed, and calculated in terms of their contribution to the conditional realization of the connection between the absorption characteristics of the material and its energy harvesting functionality. Also the multi-band absorption characteristics of no-load conditions are presented and compared with the loading conditions through the energy harvesting. As a result, 50 % of the incoming wave energy whose correspondence is 0.25 W is converted to real power through the resistive loads at 5.88 GHz.