Metamaterial absorber sensor design by incorporating swastika shaped resonator to determination of the liquid chemicals depending on electrical characteristics

In this work, sensor abilities of the metamaterial absorber based on swastika shaped resonator are developed both theoretically and experimentally at X-band frequency range. The structure is consisted of a swastika shaped resonator on the top of dielectric layer and have an air gap to fill chemicals liquids between the copper plate and backside resonator. In this study, a full-wave EM solver CST Microwave Studio (Computer Simulation Technology) based on finite integrate technique has been used to simulate and investigate the absorption of the metamaterial structure with chemicals liquids depending on the electrical properties. A vector network analyzer 85070E probe kit has been used to measure the relative dielectric constants and loss tangent of some chemical liquids (ethanol content, methanol content, acetone, methanol, ethanol, Polyethylene Glycol 300, water) in the related frequency range. Absorption value of the sensor structure for selected chemicals placed in the air gaphas been investigated. It is obtained that there is a significant difference in absorption ratios between each chemicals and overall resonance frequency shifts have been observed which provides information to accurately estimate density rate of the sensed liquids. The absorption mechanisms of the metamaterial has been explained by using electric field, magnetic field and surface current distributions. Furthermore, the resonance absorption properties of the metamaterial based absorber sensor can be modified and adjusted easily by varying the dimensions of the resonator. Experimental and simulated results demonstrate that the resonance frequency of the swastika metamaterial based sensor is linearly related to the permittivity of selected chemicals which creates an appropriate approach for multipurpose sensor devise and electrochemical sensor.