Bandwidth-enhanced dual-band dual-layer polarization-independent ultra-thin metamaterial absorber

摘要

In this paper, a polarization-independent metamaterial absorber with enhanced bandwidth at two separate frequency bands is proposed over wide angle of incidence. The proposed structure consists of two layers of dielectric substrate. The unit cell is designed on the top. surfaces of both the layers of the dielectric by parametric optimization in such a way that bandwidth-enhanced absorptions occur in C and X bands. The proposed structure is fabricated, and experimental results are in good agreement with the simulated responses. This bandwidth-enhanced dual-band absorption nature is maintained for any angle of polarization under normal incidence, thus making the absorber polarization independent in nature. The structure also shows bandwidth-enhanced dual-band absorptions over wide angle of incidence up to 45° under TE polarization and 30° under TM polarization. Moreover, the proposed structure is ultra-thin, having total thickness of 3.2 mm, ～λ/14 and λ/10 with respect to the center frequencies of two absorption bands.