Realization of an ultra-thin absorber based on magnetic metamaterial working at L-band

In this paper, at the L-band, we design and verify an ultra-thin easy-realized absorber (LUTA) based on metasurface and magnetic material. The absorptivity achieves over 90% at 1-2.51 GHz (86.04% fractional bandwidth), covering the whole L-band (1-2 GHz) and the partial S-band (2-4 GHz). The total thickness of the LUTA is as low as 3.7 mm, corresponding to 0.012 lambda(0) at the lowest operating frequency, which greatly breaks through the Rozanov limit. The excellent performance is achieved through analyzing the transmission line model of a basic absorber and then designing the metasurface layer with required impedance characteristics to make the impedance of the LUTA match with the air at the designed frequency band. The simulated absorption, power loss density, and the surface current distributions of the LUTA verify the design method, while the measured results demonstrate that the LUTA has the superiority of easy-fabrication, polarization independent, wide angle incidence, and high absorption at the whole L-band. The LUTA has great application potentials in the fields of L-band electromagnetic stealth and radar cross section reduction.