Graphene oxide dielectric permittivity at GHz and its applications for wireless humidity sensing

TL;DR

This paper investigates the dielectric permittivity of graphene oxide at GHz frequencies under varying humidity levels and demonstrates its application in a battery-free wireless RFID humidity sensor for IoT use.

Contribution

It introduces a novel humidity sensor based on graphene oxide's dielectric properties, enabling batteryless wireless humidity monitoring.

Findings

Dielectric permittivity of graphene oxide increases with humidity.

The RFID sensor's resonance frequency and phase are humidity-sensitive.

The sensor enables low-cost, battery-free humidity detection for IoT.

Abstract

Graphene oxide relative dielectric permittivity, 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 electrical property of graphene oxide was used to create a battery-free wireless radio-frequency identification (RFID) humidity sensor by coating printed graphene antenna with the graphene oxide layer. The resonance frequency as well as the backscattering phase of such graphene oxide/graphene antenna become sensitive to the surrounding humidity and can be detected by the RFID reader. This enables batteryless 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 applications.