School of Electrical and Electronic Engineering, University of Manchester, Manchester, M13 9PL, UK.
BGT Materials Limited, Photon Science Institute, University of Manchester, Manchester, M13 9PL, UK.
Sci Rep. 2018 Jan 8;8(1):43. doi: 10.1038/s41598-017-16886-1.
In this work, the relative dielectric permittivity of graphene oxide (GO), both its real and imaginary parts, have been measured under various humidity conditions at GHz. It is demonstrated that the relative dielectric permittivity increases with increasing humidity due to water uptake. This finding is very different to that at a couple of MHz or lower frequency, where the relative dielectric permittivity increases with decreasing humidity. This GO electrical property was used to create a battery-free wireless radio-frequency identification (RFID) humidity sensor by coating printed graphene antenna with the GO layer. The resonance frequency as well as the backscattering phase of such GO/graphene antenna become sensitive to the surrounding humidity and can be detected by the RFID reader. This enables battery-free wireless monitoring of the local humidity with digital identification attached to any location or item and paves the way for low-cost efficient sensors for Internet of Things (IoTs) applications.
在这项工作中，测量了在不同湿度条件下 GHz 下氧化石墨烯（GO）的相对介电常数实部和虚部。结果表明，由于吸水，相对介电常数随湿度的增加而增加。这一发现与几兆赫或更低频率的情况非常不同，在几兆赫或更低频率的情况下，相对介电常数随湿度的降低而增加。GO 的这种电特性被用于通过在印刷石墨烯天线涂覆 GO 层来创建无电池无线射频识别（RFID）湿度传感器。GO/石墨烯天线的共振频率和反向散射相位对周围湿度变得敏感，并可通过 RFID 读取器检测到。这使得可以对任何位置或物品进行数字标识的本地湿度进行无电池无线监测，并为物联网（IoT）应用中的低成本高效传感器铺平了道路。
