Polarization insensitive and wide operating angle metamaterial absorber at X-band

This paper presents the design, simulation, and experimental result of single band circular ring metamaterial absorber at 10 GHz. The metamaterial absorber is polarization insensitive and work at wide operating angle of incident electromagnetic waves. The unit cell of the metamaterial consists of a circular ring copper structure printed on 0.8 mm thick FR4 substrate. The simulated result shows that the metamaterial absorber achieves high absorbance up to 70° of incident electromagnetic waves, which is more than 85%. The full width half maximum (FWHM) for normal incident waves is 4.9% and 6.13% for simulation and measurement respectively. The operating angles which the metamaterial structure can maintain 50% of the absorbance is 82° and 83° for TE mode and TM mode respectively.