Wide incidence angle triple-band metamaterial EM wave absorber at X and Ku frequency band applications

This paper proposes a novel design for a metamaterial-based polarisation insensitive electromagnetic wave absorber for the X- and Ku-frequency bands. The Structure consists of FR4 substrates with modified split-ring resonators operating across three frequencies. Optimal design was achieved by varying the split gap and unit cell size. The proposed design has three absorption peaks (11.6, 14.04, and 16.56 GHz) with 99.88%, 99.72%, and 96.41% absorption efficiencies, respectively. A metamaterial unit cell prototype as well as an array of 13 x 13 unit cells, measuring 170 x 170 mm, were fabricated. Simulated and measured results have shown good agreement. The performance of the metamaterial absorber array is validated through measurement results. Because of its high efficiency and good quality factor, the proposed metamaterial absorber is suited for electromagnetic shielding and sensor applications. Furthermore, simulation results are used to analyse the scalability of the proposed structure.