Use of Coplanar Quarter-Wave Resonators for Glucose Sensing in Aqueous Solutions

A quarter-wave coplanar resonator in reflection configuration is presented as a novel glucose concentration sensor for aqueous solutions. This configuration allows for size reduction compared to half-wave approaches, while maintaining good sensitivities. The sensing magnitude is the unloaded quality factor, that is more sensitive to glucose changes than the resonant frequency in the 1-10 GHz range. The effects in the sensitivity of a coplanar capacitance placed in the open end are studied by simulations and measurements. The effect of the temperature on the sensitivity is also studied by experimental measurements, and discussion for more accurate sensing is offered.