Compact ultrathin polarization and incident angle insensitive dual band metamaterial microwave absorber

A double square loop based compact, ultrathin, polarization and incident angle insensitive metamaterial absorber has been presented in this manuscript. The unit cell of the proposed design comprises of double square loop on the top surface of a metal grounded dielectric substrate. The proposed design is compact with its unit cell size of 9.5 mm, i.e., λ₀/4.4 and ultrathin with the overall thickness of 0.038 λ₀ corresponding to the highest frequency of operation. The simulated results show dual absorption peaks at 3.99 and 7.15 GHz with absorptivity of 65.94% and 88.65%, respectively. The design is polarization and incident angle insensitive. The structure shows more than 90% absorptivity at both the absorption frequencies for the incidence angle of 60°. A prototype of the proposed absorber design has been fabricated and its performance has been experimentally verified for normal and oblique incidences for TE and TM polarization. The measured results are observed to be in agreement with the simulation response. The proposed design is a potential candidate for C band applications such as RCS reduction and electromagnetic compatibility etc. (author)