Mechanism of radar wave absorption and bandwidth for easy-plane Y<sub>2</sub>Co<sub>17 </sub>rare earth soft magnetic composites

Wave absorbing materials are widely used to prevent military equipment from being detected by radar wave and also serve as civil electromagnetic shielding. The absorbing properties of wave absorbing materials are determined by a combination of the electromagnetic parameters and the thickness of the composite material. In the actual case, the theoretically designed reflection loss peak intensity and the bandwidth of wave absorbing materials deviate from the engineered values. There are few reports on the mechanism about the variation of the intensity of the reflection loss absorption peak with thickness and the bandwidth of the reflection loss absorption peak. In this work, based on an interfacial reflection model, the reflective properties of radar wave at the air interface of the absorbing coating are investigated. The dependence of the matching impedance on the matching thickness of the absorbing material is determined, and the matching impedance parameters are further used to design the absorbing composites, which exhibit excellent microwave absorption properties, i.e. an average value of reflection loss is below –10 dB at 4–18 GHz in different thickness wave absorbing materials, and an average value of reflection loss is below –20 dB at 6–18 GHz in different thickness wave absorbing materials. The bandwidth of the reflection loss peak at the matched thickness is discussed in depth in principle based on the interface reflection model, and the theoretical calculations accord with the experimental results.