Highly Efficient Polarization-Insensitive EM Energy Harvester

The main challenge to converting electromagnetic waves into DC output is providing enough energy for non-linear rectification devices. This paper presents a highly efficient metamaterial perfect absorber (MPA) with stable absorption characteristics facing waves with different polarization and incident angles. Six cells have been channeled to increase the available energy at rectification sections. The final structure comprises six vertical and six horizontal channels with 12 rectifiers. The <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6× 6</tex> structure shows almost 99% electromagnetic signal absorption efficiency. The absorbed signal is transferred to the lumped element with 88% efficiency. Finally, the proposed structure has been fabricated. A strong correlation between simulation and measurement results validates the design procedure.