Dielectrics of Glucose Solutions by Broadband Transmission Line Method

A Transmission line-based microwave method is utilized to characterize the dielectrics of glucose aqueous solutions in this work. An N-type adapter pair is accurately modelized to determine the complex dielectric of the aqueous solution filled inside the chamber. Dielectric parameters of a modified two-term Debye dispersion model of the aqueous solution are retrieved from the 10MHz-18GHz spectroscopic measurements. It was demonstrated that two-term relaxation model is suitable for the selected frequency range. The dependency of the dielectric properties on various glucose concentrations in the range 50-30,000 mg/dL was evaluated. The comparison between the predicted and the measured reflection and transmission coefficient indicates this model-based transmission line method can accurately characterize the complex dielectric of various glucose aqueous solutions and can be utilized in non-invasive biomedical sensing study.