This paper presents a miniature double-stub resonant-biosensor and associated technique to quantify the glucose concentrations of two aqueous solutions localized over the sensing area of each stub. A specific procedure and the behavior of the sensor have been developed, calibrated and validated experimentally. Seven blind filling configurations have been characterized for glucose concentrations ranging from 15 to 80 mg/L and our technique predicts the glucose concentration in each channel with a root-mean-square error of 3.2 g/L. Such a level of accuracy is the tolerance range for commercial glucometer, which outlines that the microwave technique can be used for accurate glucose analysis of multiple aqueous solutions.