摘要：采用溶胶-凝胶法制备NiFe₂O₄铁氧体, 采用X射线衍射仪、场发射扫描电镜、矢量网络分析仪对样品的结构、形貌、电磁参数和微波吸收性能进行测试分析;利用匹配解析图求得样品的最佳匹配厚度和频率, 利用传输线理论计算单层NiFe₂O₄吸波涂层与NiFe₂O₄-羰基铁双层复合吸波涂层的吸波效果。结果表明, 当煅烧温度为1 200℃时, 生成颗粒呈立方体结构纯净的NiFe₂O₄样品;NiFe₂O₄样品复介电常数和复磁导率的实部较小, 虚部较大, 具有较好的频率特性, 适合制作匹配层;单层NiFe₂O₄样品的最佳匹配频率为5.92 GHz, 最佳匹配厚度为6.48 mm, 最小反射率峰值为-21 dB, 反射率小于-10 dB的频宽为3.2 GHz;当NiFe₂O₄及羰基铁层的厚度分别为1.5、0.5 mm时, 涂层反射率小于-10 dB的频宽达7 GHz。

关键词：镍铁氧体;电磁参数;匹配厚度;吸波性能;吸波涂层

Abstract：NiFe₂O₄ferrite was prepared by sol-gel method. The microstructures, morphology, dielectric properties and electromagnetic properties were analyzed by XRD, FESEM and a vector network analyzer.Impedance matching solution maps were designed to obtain the matching frequency and matching thickness. Microwave absorption properties of the NiFe₂O₄single-layer absorber coating and double-layers composite ferrite absorbing coating were studied. The results show that a pure spinel structure of NiFe₂O₄is formed at 1 200 ℃. The NiFe₂O₄ samples have good frequency characteristics that both the real of permittivity and permeability is lower and the imaginary is larger, which are suitable for the production of matching layer. The minimum reflectance of the NiFe₂O₄single-layer absorber coating is-21 dB at 5.92 GHz. The bandwidth that reflectance lower than-10 dB reaches 3.2 GHz. The bandwidth of carbonyl iron-NiFe₂O₄double-layer composite coating reflectance lower than-10 dB reaches7 GHz when the thicknesses of NiFe₂O₄ and carbonyl iron are respectively 1.5 and 0.5 mm.

Keywords：NiFe₂O₄ ferrite; electromagnetic parameter; matching thickness; microwave absorbing property; absorber coating