A Design of Metamaterial Inspired Resonator for Multifrequency Fluidic Sensors

This letter presents a multifrequency planar resonator fed by coplanar waveguide (CPW) for the determination of dispersive fluidic materials. By employing composite right-/left-handed transmission line (CRLH TL) in the resonator, the characteristic of multiresonance has been achieved in a compact size (0.17 <inline-formula> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 0.15<inline-formula> <tex-math notation="LaTeX">$\lambda_{0}^{2}$</tex-math> </inline-formula>), which can enhance the sensitivity of the resonator as a sensor at multiple frequencies. The substrate is integrated with a fluidic container made of polydimethylsiloxane (PDMS). The optimum design operates at 2.28, 2.95, and 10.6 GHz to cover both the lower and the higher frequency bands. Also, it shows very good sensitivity (0.98, 0.7, and 0.67) at each resonant frequency. Deionized water at different temperatures and water&#x2013;ethanol mixtures are used to verify the performance of the sensor in multiple frequency bands. The advantages of the proposed design, including compact size, multifrequency resonances, and high sensitivity, make it a competitive solution for detecting biological samples with similar electromagnetic properties in a single-frequency band.