基于导电塑料膜的角度不敏感宽带超材料吸波体设计及制备

Design and Preparation of Angle-Insensitive Broadband Metamaterial Absorber Based on Conductive Plastic Film

提出一种基于导电塑料膜谐振结构的超材料宽带吸波体。吸波体采用介质层膜单元阵列介质层的三层结构模型,其中上层介质兼具阻抗匹配和保护电阻膜谐振结构的作用。所采用的导电塑料膜片与基于导电墨水的电阻膜结构相比,不仅克服了加工过程中墨水厚度不均匀对方阻的影响,还可兼容激光刻蚀工艺,进而提高了谐振结构的加工精度。模拟结果表明,该吸波体在6.9~22.7 GHz的频率范围内,可以保持90%以上的入射波吸收率,相对吸收带宽为106.8%。此外,所提结构对入射波的极化特性不敏感,且对宽角入射的电磁波仍能在宽频带内实现高效吸收。更为重要的是,所提结构中的电阻膜谐振结构与介质基板可以独立加工,这种积木拼搭式的加工方案不仅节省了制备时间,还使得基底材料的选择不再受电阻膜加工的制约,为发展宽带超材料吸波体提供了新的思路。

A broadband metamaterial absorber based on a resonant structure made of conductive plastic film is proposed.The absorber adopts a threelayer structure model of dielectric layerfilm unit arraydielectric layer,in which the upper dielectric layer performs the functions of impedance matching and protection of the resistive film resonant structure.Compared with the resistive film structure based on conductive ink,the conductive plastic film adopted not only overcomes the influence of uneven ink thickness on sheet resistance during processing,but also is compatible with the laser etching process,resulting in higher processing accuracy of the resonant structure.The simulation results show that the proposed absorber can maintain an incident wave absorptivity of more than 90%in the frequency range of 6.9-22.7 GHz,with a relative absorption bandwidth of 106.8%.In addition,the proposed structure is insensitive to the polarization characteristics of incident waves,and it can still achieve efficient absorption of electromagnetic waves with wide incident angles in a wide frequency band.More importantly,its resistive film resonant structure and dielectric substrate can be processed independently.Not only saving preparation time,but also removing the restriction of resistive film processing on the choice of substrate material,such a building block type of processing scheme provides a new approach for the development of broadband metamaterial absorbers.