Non-Destructive Liquid-Mixture Sensor Using Dual-Mushroom Resonator for Glucose Concentration Characterization

This paper presents the non-destructive liquid-mixture sensor for glucose concentration characterization using the dual-mushroom resonator technique. The resonator is designed by using Jerusalem patch for reducing the size of a resonator, operating at 5.76 GHz with a total size of 10 × 30 mm
²
(0.2λ
0
× 0.2λ
0
). In the experimental measurement setup, the Teflon tube channel is placed on the top of the resonator patch. The liquid under test is filled into the Teflon tube using the syringe. The volume of the liquid under test is 100 µl. The liquid under test is a controlled temperature of 25 degrees Celcius. Six solutions, e.g., DI-water, 0.04 g/mL, 0.08 g/mL, 0.12 g/mL, 0.16 g/mL and 0.20 g/mL of D-glucose in DI-water, are selected for calibrating the proposed sensor. From the measurement results, the proposed sensor can classify the difference between D-glucose in the DI-water in each of 0.04 g/mL. The sensitivity of D-glucose solution in terms of reflection coefficient, S
11
, is 18.74 dB/g/mL. The extracted equation shows the regression coefficient better than 0.995 based on the 2
^nd
order polynomial curve fitting technique. The non-destructive microwave liquid-mixture of D-glucose and DI-water offers advantage points, e.g., low-cost, long lifetime, no-additional chemical process, etc.