Toward the use of graphene oxide-based planar inductors as a transducer for gas sensing applications

In this paper, we investigate the use of a graphene oxide (GO)-coated planar inductor as a transducer for gas sensing applications in alternating current (AC) mode. The GO is synthesized using the Hummers method and coated as a functional layer on a square-shaped planar inductor with an area of 16 x 16 mm(2) printed on a circuit board (PCB). Preliminary finite element analysis showed that the magnetic field around the inductor was tightened and amplified due to the presence of the GO layer. This result was confirmed by electrical measurements using a vector network analyzer (VNA), revealing that the GO led to an increase in the self-inductance due to its paramagnetic character. In fact, for a frequency of 1 MHz, the series resistance increased significantly by 32% compared to the initial value obtained without GO, while the inductance increased only by 0.18%. After CO2 injection, a frequency screen ranging from 1 MHz to 200 MHz demonstrated that the effect of CO2 is more relevant at low frequencies. Hence, measurements show that for 1 MHz, the series inductance and resistance decrease by about 9.33% and 31%, respectively, from their values measured after GO coating. Accordingly, this work highlights the relevance of the GO-coated inductor as a transducer for CO2 detection working in AC regime.