磁性不锈钢409L合金吸波材料的电磁与吸波性能

Electromagnetic and Microwave Absorbing Properties of Stainless Steel 409L Alloy Microwave Absorbing Materials

针对现有磁性金属吸收剂耐腐蚀性能不足的问题，以不锈钢409L粉为吸收剂、硅胶为基体制备了不同吸收剂含量的吸波材料，采用HP8722ET矢量网络分析仪对其电磁与吸波性能进行了研究。实验结果表明，在2～18GHz范围内，随着频率的增高，磁性不锈钢409L/硅胶吸波材料的介电常数实部（ε′）基本保持不变；介电常数虚部（ε″）不断增大；而磁导率的实部（μ′）和虚部（μ″）不断减小。随着409L合金吸收剂含量的增大，ε′、ε″和μ″不断增大；μ′在低频时随着体积含量的增加而增大，在高频却相反；3mm厚吸波材料最小反射率先减小后变大，吸收峰由高频向低频移动，半高宽逐渐变窄。409L体积分数为20％时，最小反射率为-17．8dB，其对应的峰值频率为9．4GHz，有效带宽（≤-8dB）达到5．27GHz（7．03—12．3GHz）；体积分数为30％时，最小反射率为-24．1dB，其对应的峰值频率为6．3GHz，有效带宽（≤-8dB）达到4．5GHz（4．2—8．7GHz），在X和C波段具有较好的吸波性能。而且通过对材料进行二层设计，能够有效地进行宽频吸收，具有一定的应用前景。

In view of the poor corrosion resistance of existing magnetic metals absorbents, microwave absorbing materials were prepared by using silicon rubber as matrix and stainless steel 409L alloy with different volume content as absorbents. The electromagnetic and microwave absorbing properties of the samples were examined by HP8722ET network analyzer. The results indicated that with increasing frequency in 2-18GHz the real part of permittivity （ε′） of magnetic stainless steel 409L alloy/silicon rubber absorbing materials changes slightly, the imaginat：y part of permittivity （ε″） increases, and the complex permeability （μ′ andμ″） decrease; with the increase of FeCr alloy volume fraction, ε′、ε″ and μ″ increase, however μ′ increases in low frequency and decreases in high frequency. The minimum reflectivity of 3mm thick absorbing materials first decreases, then increases with increasing FeCr alloy volume fraction, with the absorption peak moveing from higher frequency to lower frequency, and the FWHM becoming narrow. The 3mm thick absorbing materials with 20vol% 409L alloy has the minimum reflectivity of -17.8dB at 9.4GHz, the reflectivity exceeds --8dB in 7.03 to 12.3GHz; when the volume content reaches 30%, the minimum reflectivity is -24.1dB at 6.3GHz, the reflectivity exceeds --8dB in 4.2 to 8.79GHz. The 409L alloy/ silicon rubber microwave absorbing materials possess good microwave absorbing properties in the X- and C-band, and by designing double-layer structure, the material can achieve broadband absorption, and has a broad application prospect.