Broadband Absorber with High Angular Stability Based on Magnetic Material

This paper proposes a broadband absorber that exhibits excellent angular stability. A unit cell is formed by stacking a modified magnetic material layer, an air spacer layer and a grounded magnetic material layer. An equivalent circuit model (ECM) is established for the absorber. Studying the surface impedance and the conditions in which the absorption rate surpasses 90% at various incidence angles. Furthermore, a prototype is fabricated, assembled, and measured to confirm the operation feasibility of the absorber. The experimental results demonstrate a stable absorption band (| S ₁₁ |≤–10dB) between 2.4GHz and 7.3GHz under normal incidence, with a fractional bandwidth (FBW) of 101% and a relative thickness of 0.099λ _L . When the incident angle θ reaches 60°, the absorption performances remain same for TE- and TM-polarized oblique incidences. The measured results demonstrate that the absorber attains an absorption rate of over 80% within the ±70° airspace range.