Perfect absorber with separated ‘dielectric–metal–ground’ metamaterial structure

Abstract

A metamaterial perfect absorber whose effective thickness is less than one thousandth of the operating wavelength is proposed. Different from the traditional "metal-dielectric-ground" type metamaterial absorber, it adopts a novel "dielectric-metal-ground" structure, and the "dielectric-metal" structure is separated from the "ground". By this design, the effective thickness of the absorber is reduced to about 1/2200 wavelength. It will make the absorber suitable for the applications of imaging and sensing. Next, a bi-material cantilver absorber based on the proposed structure is designed and fabricatied to demonstrated the high absorption properties in the case of ultra-thin thickness. In addition, a reflective spectroscopy system based on the vector network analyzer is built to test the absorption performance. The measured results show it has an absorptivity of close to 97% at 94GHz and are in good agreement with simulations.