Determination of the liquid chemicals depending on the electrical characteristics by using metamaterial absorber based sensor

Abstract

In this paper, the metamaterial absorber based chemical sensor has been designed and measured experimentally. The proposed structure composed of gammadion copper resonator on the top of the FR4 substrate. There is an air gap between the copper plate and backside resonators to place the chemicals. Finite Integration Technique based high-frequency electromagnetic CST microwave studio has been used to simulate and observe the absorption changes of the chemicals depending on the electrical characteristics. The study has been carried out at the X-band frequency range (8-12 GHz). In the first stage, the relative dielectric constants of chemical liquids (acetonitrile, acetone, methanol, ethyl alcohol and benzene) have been measured by using vector network analyzer 85070E probe kit in the related frequency range, the absorption value of the sensor structure is observed for each chemical placed in the air gap region. It is obtained that there is a significant absorption difference between each chemical. Mechanisms of absorption have been presented through the surface current and electric field on gammadion resonator. Furthermore, the effect of the variation dimensions of the resonator on absorption value has also been investigated. The measured values are in good agreement with the simulation ones. In this perspective, the proposed structure is a good candidate for a future electrochemical sensor with instantaneous response.