TRIPLE-BAND POLARIZATION-INDEPENDENT ULTRATHIN METAMATERIAL ABSORBER

A novel triple-band ultrathin metamaterial absorber (MA) with polarization independence is designed, characterized and realized in this study. The designed absorber consists of three layers. The top metallic patch is patterned in an ultrathin dielectric substrate that is backed with a ground metallic plate. The numerical simulation results show that the presented metamaterial absorber exhibits three distinct absorption peaks of 99.95%, 99.28% and 96.36% under normal incidence at frequencies of 8.115, 11.4 and 15.12 GHz, respectively. Due to its fourfold symmetry, the absorbing properties are independent of the polarization of the incident radiation angle. Moreover, in the cases of TE and TM polarization modes, the proposed absorber displays an outstanding absorption response over a wide range of incident angles up to 60◦. The physical mechanism of the absorption performance is explained by investigating the normalized input impedance, surface current and field distributions at three distinct absorption peaks. Furthermore, the presented absorber is practically validated by the excellent agreement observed between the experimental and simulated results. The designed absorber has an ultrathin thickness of 1mm, which is 0.027λ0 with respect to the lowest peak absorption frequency, and can be useful for several potential applications, such as electromagnetic compatibility, stealth technology and super lenses.