High Resolution Microwave Glucose Sensing System Based on Active Fano Resonator Using Injection‐Locked Oscillation

Self‐monitoring of blood glucose is a critical component of diabetes mellitus treatment. Microwave‐based noninvasive blood glucose detection offers advantages such as reduced risk of infection, high accuracy, and lower cost. To address the demand for miniaturized systems in noninvasive continuous glucose monitoring (NCGM), this study proposes a compact microwave sensing system based on active Fano resonance, utilizing injection‐locked oscillation (ILO). The microwave sensing system integrates spoof localized surface plasmons (LSPs) resonators and an active gain‐assistant circuit to compensate for losses, where Fano resonance is generated through the coupled resonators and further enhanced by ILO phase tuning. The size of the sensing detection system is 60 × 60 mm. Consequently, the quality factor (Q‐factor) increases substantially from 51 to 115 397 and the resonance intensity rises from 19 to 68 dB. Experiments demonstrate that, within a glucose concentration range of 100–400 mg dL −1 , the sensing system achieves a resolution of 10 mg dL −1 . In both the glucose solution concentration sensing experiment and the real‐time in vitro continuous glucose monitoring (CGM) sensing validation, the system demonstrates outstanding detection performance. This study offers a robust, precise, and real‐time solution for NCGM.