Broadband metamaterial absorber based on magnetic substrate and resistance rings

A broadband metamaterial absorber was designed based on magnetic substrate and resistance rings. The absorber is composed of three layers coupling structures of resistance rings, magnetic absorbing layer and a metal plane. A full-wave electromagnetic simulation had been performed based on the finite-difference time-domain (FDTD) method. The optimized thickness of metamaterial absorber is 2 mm, two absorption picks at 7.58 GHz and 12.75 GHz are achieved. The absorption of this metamaterial absorber below −10 dB is from 6.76 GHz to 15.97 GHz. A strong electromagnetic resonance is excited by the resistance rings structure to improve the absorption in low-frequency. The absorption of MMA is originated from magnetic loss and dielectric loss in magnetic substrate. Finally, the sample of metamaterial absorber was fabricated and tested, the experimental results is basically consistent with the simulated results. The proposed metamaterial absorber has many advantages, such as thin thickness, broadband, and polarization insensitivity.