An ultra-thin triple band polarization-insensitive metamaterial absorber for C-band applications

An ultra-thin triple band polarization-insensitive metamaterial absorber has been presented in this paper. The unit cell of the proposed structure consists of three concentric rings in the top layer of metal-backed dielectric substrate. The simulated result shows that the proposed structure has triple band absorptivity response lying in C band. The structure exhibits polarization-insensitive behavior under normal incidence due to four-fold symmetry. It also shows high absorption under oblique incidence upto 60° for both TE polarization (above 75%) and TM polarization (above 90%), thus validating the wide angle characteristics. The absorption mechanism is explained through illustrating the electric and magnetic field along with the surface current distribution. The proposed structure has been fabricated and measured, which shows good agreement with simulated response, thus verifying the polarization-insensitivity and wide angle characteristics.