Bilkent University, Department of Physics, 06800 Ankara, Turkey.
Nat Commun. 2015 Mar 20;6:6628. doi: 10.1038/ncomms7628.
Radar-absorbing materials are used in stealth technologies for concealment of an object from radar detection. Resistive and/or magnetic composite materials are used to reduce the backscattered microwave signals. Inability to control electrical properties of these materials, however, hinders the realization of active camouflage systems. Here, using large-area graphene electrodes, we demonstrate active surfaces that enable electrical control of reflection, transmission and absorption of microwaves. Instead of tuning bulk material property, our strategy relies on electrostatic tuning of the charge density on an atomically thin electrode, which operates as a tunable metal in microwave frequencies. Notably, we report large-area adaptive radar-absorbing surfaces with tunable reflection suppression ratio up to 50 dB with operation voltages <5 V. Using the developed surfaces, we demonstrate various device architectures including pixelated and curved surfaces. Our results provide a significant step in realization of active camouflage systems in microwave frequencies.
雷达吸波材料用于隐身技术，可使物体从雷达探测中隐藏起来。电阻和/或磁性复合材料用于减少反向散射的微波信号。然而，这些材料的电性能无法控制，这阻碍了主动伪装系统的实现。在这里，我们使用大面积的石墨烯电极，展示了能够实现微波反射、传输和吸收的电控制的有源表面。我们的策略不是调整体材料的性质，而是依赖于在原子薄电极上静电调整电荷密度，该电极在微波频率下作为可调谐金属工作。值得注意的是，我们报告了具有大尺寸的自适应雷达吸波表面，其可调反射抑制比高达 50 dB，工作电压 <5 V。使用所开发的表面，我们展示了各种器件架构，包括像素化和曲面。我们的结果在微波频率下实现主动伪装系统方面迈出了重要的一步。
