Electromagnetic-based ethanol chemical sensor using metamaterial absorber

We proposed a novel electromagnetic-based chemical sensor that is realized by using a metamaterial absorber. The metamaterial absorber comprises a split-ring-cross resonator (SRCR) and a microfluidic channel. The SRCR can generate LC resonance that is very sensitive to changes in the effective dielectric constant around the capacitive gap. In addition, microfluidic channels can change the effective dielectric constant of the dielectric substrate by using an infinitesimal quantity of a liquid on the order of microliters. The proposed chemical sensor can detect the electrical properties of any unidentified liquids injected into the channels, as well as concentration changes in the liquids. The performance of the proposed sensor is demonstrated using the absorption measurements of a fabricated prototype sample with waveguides. In addition, the relationship between the absorption frequency and chemical concentration is demonstrated.