This study proposes a new sensor that detects the glucose concentration of an aqueous solution with increased resolution. It is aimed at the realization of a wearable non-invasive glucose sensor for diabetes patients in future. A modified complementary split-ring resonator (CSRR) is used to determine the concentration by exploiting the change in frequency when an aqueous solution is applied. The Q-value enhancement circuit technique at several GHz is applied to the CSRR to cancel out the loss of a lossy aqueous solution. A prototype of the sensor is developed. The Q-value increases from 30 to over 500 at 5.2 GHz for a glucose solution with a concentration of 100 mg/dl. The measured sensitivity is 69 MHz/% for aqueous glucose solutions with concentrations ranging from 0-10 wt%.