Measuring Glucose Content in Aqueous Solutions by means of Split Ring Resonator (SRR) Loaded Transmission Lines

It is shown in this paper that a pair of uncoupled microstrip lines each one loaded with a split ring resonator (SRR) in a symmetric configuration is useful to measure the solute content in very diluted solutions. The principle of operation of this microwave sensor is symmetry disruption, achieved by loading one of the SRRs with the solvent (reference liquid) and the other one with the solution (liquid under test -LUT). To this end, the structure is equipped with a pair of fluidic channels. The output variable of this sensor is the cross-mode insertion loss (in linear form), very sensitive to small perturbations between the reference liquid and the liquid under test. The structure, applied to the measurement of glucose concentration in deionized (DI) water, is able to resolve glucose concentrations of 2.5g/L and the maximum sensitivity is 0.0036 (g/L)
^-1
.