An Ultra-Thin, Bandwidth Enhanced Metamaterial Absorber for X-Band Applications

A simple metamaterial absorber with ultra-thin structure has been proposed for X-band applications with enhanced absorption bandwidth. The proposed structure comprises of circular rings embedded in L-shaped resonators. This ultra-thin structure (0.0420λ0 thick with respect to the center frequency of the operating bandwidth) exhibits wide absorption of 2.3 GHz above 90% absorptivity from 9.4 to 11.7 GHz. The designed structure was tested for different polarization for transverse electric mode under normal and oblique angles of electromagnetic wave incidence. It is polarization sensitive because of its asymmetrical design, and has diverse impacts on absorption at various incidence angles. The electromagnetic fields and surface current distributions were analysed to understand the high absorption of the presented metamaterial absorber. The proposed structure has been fabricated and the experimental responses were matched closely with the simulated responses. This metamaterial absorber will be suitable for applications like stealth technology in X-band frequencies.