基于石墨烯光电特性的超宽带可调超材料吸波体设计

利用石墨烯的电导率可调特性设计了一种超宽带可调超材料吸波体。模拟计算了不同石墨烯费米能级时吸波体的吸收率，结果表明，当石墨烯费米能级为0.7 eV时，吸波体在1.74 GHz ~10.44 GHz 的吸收率保持在90%以上，实现了电磁波的超宽带吸收；当改变外加电压使石墨烯的费米能级从0.7 eV逐渐减少到0 eV时，吸波体在1.74 GHz~10.44 GHz的吸收率逐渐下降，其调制深度可达53.8%，实现了吸收率可调的功能；通过对表面电流分布进行仿真与分析，阐述了其电磁波宽带吸收及吸收率可调的机理；模拟分析了石墨烯费米能级为0.7 eV时，入射波极化状态和入射角度对吸波体吸收特性的影响，结果表明，由于结构单元的旋转对称性，吸波体的吸收特性具有极化不敏感的特点；随着电磁波入射角度的增大，其吸收率逐渐降低。

Design of ultra-wideband tunable metamaterial absorber based-on electro-optic properties of graphene

This paper proposed an ultra-wideband tunable metamaterial absorber based on conductivity tunable property of graphene. At first, we simulated the absorption of absorber under different Fermi level of graphene. The results showed that the absorption was above 90% from 1.74 GHz to 10.44 GHz when the Fermi Level was 0.7 eV; it achieved the property of ultra-wideband absorption. When the Fermi level of graphene decreased from 0.7 eV to 0 eV by changing the applied voltage, the absorption between 1.74 GHz and 10.44 GHz gradually decreased, the maximum modulation depth could reach 53.8%, it achieved the property of tunable absorption. Secondly, we studied the distribution of surface current to explore the physical mechanism of ultra-wideband absorption and absorption adjustment. Finally, we simulated and analyzed the influence of polarization and incident angle on the absorption property when the Fermi level of graphene was 0.7 eV. The results showed that the absorption was insensitive to polarization due to the rotational symmetry of structure unit, but the absorption gradually decreased with the increase of incident angle.