Ferrite-based metamaterial microwave absorber with absorption frequency magnetically tunable in a wide range

Abstract

A metamaterial absorber with a near-perfect absorption peak, which is tunable magnetically in an ultra-wide frequency range from 0.2 to 7.6GHz, is proposed and fabricated by combining a ferrite with a metastructure. In our design strategy, the adjustable resonance frequency of the ferrite by external magnetic field provides the tunability, while the metastructure of periodic metal strips eliminates the polarization conversion brought by the ferrite and further enhances the absorption via diffraction and interference mechanisms. The measured absorption of the as-fabricated ferrite-based tunable MMA is in good accordance with the simulation results, validating the design method. Our results here illustrate that the ingenious integration of metamaterials with traditional ferrite materials promises a way to achieve a wide frequency tuning range of a strong absorption band, especially in low frequency bands.