一种基于石墨烯的超宽带吸波器  

An ultra-wideband absorber based on graphene

作　　者：姜彦南[1,2,3] 王扬[2] 葛德彪[4] 李思敏 曹卫平[1,2] 高喜[1,2] 于新华[1,2,3] 

机构地区：[1]广西无线宽带通信与信号处理重点实验室,桂林541004 [2]桂林电子科技大学信息与通信学院,桂林541004 [3]桂林电子科技大学,广西信息科学实验中心,桂林541004 [4]西安电子科技大学物理与光电工程学院,西安710071

出　　处：《物理学报》2016年第5期75-82,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61361005,61461016,61161002,61561013);广西自然科学基金(批准号:2014GXNSFAA118283,2014GXNSFAA118366,2015GXNSFAA139305);桂林电子科技大学创新团队和认知无线电与信息处理省部共建教育部重点实验室(桂林电子科技大学)主任基金资助的课题~~

摘　　要：隐身技术对降低飞行器目标的雷达散射截面、提高飞行器目标的生存能力具有重要的意义和价值,而在飞行器目标上引入吸波器结构是一种重要的隐身手段.然而,目前已有吸波器的研究主要集中在单频或多频窄带方面.为了拓展吸波器工作频带,基于石墨烯材料提出了一种工作于S/C波段的新型超宽带吸波器模型单元,其中包含一个用石墨烯材料设计的方圆形双环周期结构.调节石墨烯的表面阻抗,使得吸收率超过90%的频带范围为2.1—9.0 GHz,相对带宽约为124%,实现了超宽带的吸波特性;鉴于模型的高度对称性,提出的吸波器模型表现出对入射波极化不敏感的吸波特性;在不改变模型结构情况下,调节石墨烯的静态偏置电场,亦可调控吸波器谐振在2.0—9.0 GHz频带范围内的任意频率点处,且达到超过99%的吸收效果.最后采用等效电路模型方法和波的干涉理论对其吸波机理进行深入研究与分析:从等效电路角度来讲,方形和圆形环分别引入高、低吸波谐振频率,二者优化叠加拓展了吸波带宽;从干涉理论方面来看,吸波器表面处的首次反射波与透射波的多次出射波形成较强的干涉相消现象,有效减少了吸波器的反射回波.Stealth technology is of great importance and significance in reducing the radar cross section and improving the survivability of the target aircraft. Absorber is one of the most important structures in stealth technology. However, the present investigations of absorbers mainly focus on the narrow band or multi-band. To extend the operation bandwidth,a graphene-based absorber structure is proposed in this paper. The proposed absorber has a periodic structure whose unit cell consists of a square and a circular graphene-based ring. The surface impedance of the periodic structure can be optimized to match the impedance of the free space in a very wide band by adjusting the electrostatic bias voltage.Then the operation band is significantly extended. By using the commercial software, CST Microwave Studio 2014, the performance of the proposed absorber is studied. The simulated results show that the proposed absorber can absorb electromagnetic（EM） waves in an ultra-wideband from 2.1 to 9.0 GHz, with an absorbing rate of up to 90%. Moreover,the proposed absorber is insensitive to the polarization of the incident wave due to the symmetry of the structure. We also find that the absorber can be tuned to work at any frequency in a range from 2.0 to 9.0 GHz for a fixed geometrical parameter. The equivalent circuit model（ECM） approach and interference theory（INF） are employed to investigate the physical mechanism of the proposed absorber. According to the ECM, we analyze the resonant characteristics of the square and circular graphene rings. Owing to the existence of two different graphene rings, two resonant frequencies are detected. By optimizing the structure parameters of the graphene rings, the two resonant frequencies are brought closer, resulting in the increase of the operation band. On the other hand, the real part of the input impedance of the equivalent circuit reaches up to about 300 Ω, and the imaginary part is close to 0 Ω, which provides good matching to the free space, leading to high absorption

关 键 词：超宽带吸波器 石墨烯 等效电路模型 干涉理论 

分 类 号：V218[航空宇航科学与技术—航空宇航推进理论与工程]