摘要
BaTiO_3介电材料在微波频段具有良好的介电频散特性,可通过在羰基铁粉吸收剂中掺杂 BaTiO_3改良其频散特性。采用固相合成法在不同温度下制备了 BaTiO_3粉体,测试表明,制备的 BaTiO_3粉体形成了单一的四方相晶体结构,具有很高的纯度和结晶度、较好的频散特性。在羰基铁粉中掺杂不同含量的 BaTiO_3粉体,使用同轴线方法测试了复合粉体在2～18 GHz 频段范围内的介电常数和磁导率,基于传输线理论计算获得了复合粉体的反射系数,对比结果显示:BaTiO_3粉体的掺入,明显改进了羰基铁粉介电常数的频散特性,有效地提高了低频波段(2～5 GHz)的吸收性能,含有4%BaTiO_3(质量分数)的样品在3 GHz 处的反射系数达到-8 dB。适当比例 BaTiO_3和羰基铁的混合粉体有望成为性能优越的低频波段吸波材料。
Because of the good frequency dependence characteristic of BaTiO3 in the microwave band, it could be used to improve the absorbing properties of carbonyl iron powder by mixing. BaTiO3 powder was prepared by solid-phase synthesis method under different temperatures, X-ray diffraction and other tests show that the powder has a single tetragonal crystal structure with high purity, crystallinity and good frequency dependence characteristics. The complex permittivity and permeability of carbonyl iron powder doped with different contents of the BaTiO3 powder were measured using coaxial line method. Meanwhile, reflection loss was calculated based on transmission line theory. Results show that remarkable improvements were found in frequency dependence characteristic of permittivity and absorbing performance in 2-5 GHz. The reflection coefficient of the sample containing 4wt% BaTiO3 powder is up to -8dB. The carbonyl iron powder doped with appropriate amount of the BaTiO3 powder can be good absorbing materials in low-frequency-band.
关键词
微波吸收材料
羰基铁
钛酸钡
介电常数
反射系数
microwave absorbing material
carbonyl iron powder
BaTiO3
permittivity
reflection coefficient
