基于激光微加工的薄膜型微波吸收材料研究

For metal patterned films, the surface cell size of them has a great influence on their permittivity. Based on the effective medium theory, the influence of cell size on the permittivity of patterned films is calculated with a normalized metal permittivity as the calculation parameter. Meanwhile, micromagnetic software based finite element principle is used to research the influence of cell size on the microwave magnetic properties. The samples for research will be prepared by a centripetal sputtering method on the flexible substrates. The diameter of all the samples is up to 8 inch, and excellent soft magnetic properties will be achieved with real part and imaginary part of complex permeability up to 200. The patterned films could be achieved by the micro-manufacture base on the excimer laser, and various film patterns could be finished by various micro-manufacture method. The permittivity of metal films could be tuned by this way and drop to an appropriate range to match with the incident microwave. The patterned films with various microwave properties could be superposed to form a film-type microwave absorption material to meet the application demand in the L freqency range. It is a promising material for microwave absorption applications in the future.

本项目基于重整化的金属介电常数，利用有效媒质理论来计算表面刻画薄膜微观单元尺寸大小对薄膜微波介电物性的影响规律；利用微磁有限元软件来模拟刻画薄膜单元尺寸对薄膜微波磁性影响规律。利用向心溅射的方式在软基底上制备面积达8英寸的高磁导率实部和虚部（2GHz时达到200以上）的软磁金属膜。并采用准分子激光微加工的方式在薄膜表面加工出微米量级的微观单元，实现对金属薄膜的介电调控，使其介电常数降到可以和入射电磁波匹配的范围。并通过将不同微波物性的金属膜进行复合，制备出满足L波段应用需求的薄膜型微波吸收材料，解决当前在军民两用方面极度缺乏的L波段轻质、薄层微波吸收材料问题，对促进我国微波吸收材料的大跨度进步具有积极意义。

对于图形化的金属膜，基于重整化的金属介电常数,使用有效媒质理论对图形化金属单元的介电常数进行模拟计算,结果表明当金属单元尺度小于10um的时候,金属膜的有效介电常数能够被充分降低。同时基于有限元计算进行模拟，模拟结果和有效媒质理论结果基本符合，证明了有效媒质理论研究不连续金属膜的有效性。使用微磁学方法对图形化磁性薄膜的磁性能进行仿真，结果表明，图形微结构的有序化会导致薄膜产生一个宏观的磁各向异性，使其可以在一定频率下产生自然共振。在此理论指导下，采用光刻技术制备图形化金属薄膜，并基于共面波导技术对薄膜介电常数和磁导率进行测量。初步结果表明，图形化薄膜的介电常数可以控制在阻抗可匹配的范围内，可以进一步基于此制备高性能微波吸收材料。