Boosting magnetic loss and impedance matching based on laminated structure for balancing low-/high-frequency broadband microwave absorption

Balancing low-/high-frequency broadband absorption is significantly essential for realizing ultra-wideband microwave absorption but mains challenging. In this work, laminated dielectric@magnetic FePO4/CrPO4@FeSiCr flakes have been created using facile vertical ball milling technique and subsequent phosphate passivation process. The flaky morphology provides the strong magnetic loss ability for boosting a lower-frequency microwave absorption. The dielectric@magnetic structure contributes good impedance matching and sufficient double loss mechanism for ensuring a wideband higher-frequency microwave absorption. The unique laminated structure is benefit for multi-scattering and reflection, which can balance the low-/high-frequency broadband absorption. With 6 h ball milling, FePO4/CrPO4 hybrid layer covers FeSiCr flakes deliver effective absorption bandwidth (EAB) of 1.6 GHz covering 2.4–4.0 GHz (S-band) with 3.2 mm, EAB of 3.52 GHz covering 4.40–7.92 GHz (C-band) with 1.9 mm and EAB of 8.24 GHz covering 9.36–17.6 GHz (X+Ku band) with 1.1 mm. Generally, an easy pathway is provided in this work for developing ultra-wide microwave absorbers that balance low-/high- frequencies.