Loss tangent effect on the accurate design of microwave sensors for blood glucose monitoring

The effect of loss tangent variation is properly faced in this work for the accurate design of microwave sensors to be applied in the non-invasive monitoring of blood glucose. Bio-antenna optimization is performed by accurately considering the complex permittivity variation of the biological radiation medium. At this purpose, preliminary dielectric data are experimentally collected by using a standard open-ended coaxial probe. Then, the above complex dispersive data are exploited to optimize the antenna dimensions. Return loss measurements on water-glucose solutions with different concentrations are reported to prove the strong enhancement in the prediction of the resonant shift due to the variation of glucose level, when properly considering the loss tangent variation. Preliminary simulation results on blood are also reported.