Polarization-independent perfect metamaterial absorber for C, X and, Ku band applications

Abstract In this paper, a polarization-independent perfect absorber with near-zero index metamaterial (NZIM) property is proposed. Conventional FR4 substrate without any lumped or substrate-embedded elements has been used with a unique patch of the swastika-shaped capacitive gap along with inductive tails at 90-degree rotational symmetry. The simulation results for both the unit cell and the array for co-polarized waves at normal and oblique incidences up to 90° has shown near unity absorptions at 4.238, 7.836, 10.482, 11.014 and 13.352 GHz along with near zero values of permittivity, permeability, and refractive index. The cross-polarization analysis has proved its perfect absorption capability. The absorber has shown 14 GHz of near-zero refractive index at the entire operating frequency range. The equivalent circuit analysis and measurement of both the array and the unit cell were in good agreement with simulation results, which proved it as a perfect NZIM absorber to enhance antenna gain and directivity and other sensing applications at C, X and Ku band.