Oblique incidence-insensitive metamaterial absorber using strong magnetic coupling resonance for low-frequency microwave absorption

In this work, we presented an oblique incidence-insensitive metamaterial absorber (MA) based on the strong magnetic coupling resonance using the printed circuit board process, and the spacer is produced by a typical magnetic absorber material (MAM). As for reflection loss (RL) at oblique angles, it can achieve high-efficiency absorption for both transverse-electric (TE) and transverse-magnetic (TM) polarizations with a wide angular range from 0° to 60° in the low frequency of 2.33 GHz to 3.44 GHz. In addition, the magnetic coupling mechanism of the metamaterial absorber was deeply analyzed. Comparing the results of the simulation and experiment, it displays excellent absorption performance of the proposed absorber in TE and TM modes under large oblique incidence angles.