Unifying approach to multilayer metamaterials absorber for bandwidth enhancement

Abstract In this work, we theoretically investigate the multilayer absorber with metal/ dielectric/metal functional layers. The model is tested by the numerical simulations, yielding agreeable results with analytical calculations for the number of layers up to 40. From that model, an approach to achieve wideband absorption is deduced: by either adding more layer or arranging adjacent unit cells close to each other. The validity of this method is verified with simulations in which a 40-layer structure obtains near perfect absorption at 0.69 THz and maintain its absorption strength higher than 90% in a 0.12-THz bandwidth. Compared to common pyramid-like multilayer absorbers, our proposal can also achieve a bandwidth enhancement while having clear advantages in fabrication simplicity.