Highly sensitive quarter-mode spoof localized plasmonic resonator for dual-detection RF microfluidic chemical sensor

Abstract

In this paper, benefitting from the presence of an ultrathin corrugated metal–insulator–metal ring resonator, for the first time, we proposed a dual-detection microfluidic chemical sensor based on quarter-mode spoof localized surface plasmon (LSP) resonator with higher sensitivity among all the dual/multichannel microwave chemical sensors. First, we study full-mode spoof plasmonic resonator and we show that the resonance modes of the quarter-mode structure are exactly one-fourth of the full-mode structure. By placing two asymmetric microfluidic channels in the strongest E-field regions, the capability of detecting two aqueous solutions is feasible. By utilizing a 85070E performance probe connected to vector network analyzer, we determined the relative permittivity and loss tangent of fluids under test. Then, the fabricated prototype was tested, and our experimental results collaborate well our simulation predictions. Our proposed RF sensor exhibits 87% growth in sensitivity () compared with the most sensitive multichannel microwave chemical sensor that previously existed. Furthermore, we show that our elaborately designed sensor has the potential to detect chemicals with very close dielectric constant corresponding to 1,4-Dioxin, Cyclohexane, n-Hexane with the relative permittivity of 2.12, 2.012, 1.95, respectively.