Thin wideband infrared metamaterial absorber with coplanar metallic patches of different sizes

Infrared absorber concept is a vibrant research topic because of the importance of real world applications such as infrared detectors, thermal coolers and energy harvesters. In this paper, we propose and numerically analyze thin metamaterial structures designed to operate in Long Wave Infrared Region, one of the regions that atmosphere shows transparent behavior. It is demonstrated that one of the proposed structures attains absorptance values higher than 80 percent in the wavelength region from 8.14 μm to 11.59 μm. The absorber is thin with a thickness of about 700nm, excluding any additional substrate layer that might be needed for mechanical support. The absorber design approach used in study can be further improved to achieve even flatter absorption spectrum over the LWIR band optimizing the design parameters.