Two-dimensional Highly Sensitive Wireless Displacement Sensor with Bilayer Graphene-based Frequency Selective Surface

In this paper, a two-dimensional wireless displacement sensor with high sensitivity composed of a bilayer graphene-based frequency selective surface (FSS) is proposed. The lengths of the strip-type resonators on the top and bottom layers of the FSS are different and perpendicular to each other. Based on the resonance and polarization characteristics of the FSS, two-dimensional displacement sensing can be realized. It is well validated both in simulation and experiment that the direction of the displacement can be distinguished by the variation trend of the resonant frequencies of the top and bottom layers. In experiment, the measured results of the FSS based wireless displacement sensor in the dynamic range of 5mm show high sensitivity of 280 MHz/mm in x direction and 370 MHz/mm in y direction. Moreover, the excellent mechanical and chemical stability of the multi-layer graphene also makes it suitable for harsh environments, showing good prospects in application.