Non-Invasive Glucose Detection Using Novel Microwave Active Biosensor Based on Plasmonic Metamaterial

Painless, non-invasive, and continuous glucose monitoring is highly desired to improve the diabetes management. In this study, a novel reconfigurable dual-mode microwave active biosensor is proposed for continuous noninvasive glucose detecting. This plasmonic metamaterial-based biosensor is achieved by combing a controllable spoof surface plasmon polariton (SSPP) waveguide and a resonator based on spoof localized surface plasmon (SLSP). The SLSP-based resonator is excited by electromagnetic coupling with the SSPP waveguide, and two resonance modes of this biosensor are selected and used to realize glucose sensing. Furthermore, by dynamically tuning the capacitance of the varactor diodes integrated on the SSPP waveguide, the resonance frequencies can be flexibly adjusted. The characterization of glucose level is carried out by scrutinizing shifts in two resonance frequencies. To effectively combine the results obtained from different operating states of the biosensor, an integrated sensing method is implemented, which can effectively improve the sensitivity of the biosensor. Different concentrations of glucose aqueous solution are utilized to mimic the blood glucose levels. The measured results show that this biosensor provides a wide glucose concentration range of 0-800 mg/dL, which can fully meet the requirement of the diabetes management. And the biosensor achieves a high sensitivity of 3.34×10
^-2
and 6.51×10
^-2
MHz/(mg/dL) for two resonance modes.