Broadband microwave absorption property of a thin metamaterial containing patterned magnetic sheet

A new type of thin and broadband metamaterial absorbers containing patterned magnetic sheet as the middle layer in the tri-layer structure are presented in this article. Those absorbers with more than 12GHz absorption bandwidth which reflectivity is below -10dB in the measured frequency 2-18GHz were designed and experimentally realized by the thickness only in 1.8mm. Design and experiment results display a huge expanded absorption bandwidth comparing to tri-layer absorber with complete sheet (not patterned sheet) as middle layer. By analysing the electric field distribution, it is found that the scattering effect caused by the patterned magnetic sheet plays a vital role in the feature of expanded bandwidth. Our results demonstrate that the great practicable method of broadening the absorption bandwidth and achieving lower total weight of thin magnetic absorber can be realized by the incorporation of patterned magnetic sheet.