取向吸波贴膜电磁性能研究

提高吸波材料的电磁性能,是新型电磁波吸收材料的重要研究内容。采用朗道-利夫希兹-吉尔伯特(LLG)方程、等效媒介理论和传输线理论,分别对随机取向和一致取向吸波贴膜的本征磁导率、等效磁导率和反射损耗进行了计算。计算结果表明当微波吸收剂一致取向时吸波材料的本征磁导率、等效磁导率和反射损耗均有显著提升。通过改变吸波贴膜内部吸收剂空间排布的方式,可以有效地提高吸波贴膜的电磁性能。针对流延法制备吸波贴膜的过程,对刮刀下流延浆料速度曲线和微波吸收剂取向之间的关系进行了分析,通过微波吸收剂的取向张量对吸波贴膜的取向程度进行了表征。通过改变流延过程中的物理参数,可以调控吸波贴膜的取向状态。

Electromagnetic properties of oriented microwave absorbing film

Improving the electromagnetic properties of microwave absorbing film is one of the most important approaches to develop the new generation electromagnetic wave absorbing materials.The intrinsic permeability,the effective permeability and the reflection loss of the microwave absorbing film with oriented or unoriented flake-shapes particles were calculated using the Landau-Lifshitz-Gilbert equation,Maxwell-Garnett’s effective medium theory and the Transmission Line Theory.The calculated results show that the oriented microwave adsorbing film has greater intrinsic permeability,effective permeability and reflection loss compared with the unoriented one.The electromagnetic properties of microwave absorbing film can be effectively improved by controlling the orientation of flake-shaped particles.Considering the tape casting process,the relationship between the velocity profiles of the slurry in the blade and the orientation of flake-shaped particles was analyzed,and the orientation condition of the microwave absorbing film was characterized by the orientation tensor of the flake-shaped particles.The orientation of flake-shaped particles can be controlled by changing the working parameters of the tape casting process.