Noninvasive in vitro measurement of pig-blood d-glucose by using a microwave cavity sensor

We have developed an electromagnetic microwave cavity sensor based on the resonant frequency shift for real time measurement of the glycemia in pig blood. We could determine the concentration of d-glucose in pig blood in the range of 150–550 mg/dl at the resonance frequency near 4.75 GHz with a bandwidth of 300 MHz. The change in the d-glucose concentration in blood brings microwave reflection coefficient S11 changes of about 6.26 dB and resonance frequency shifts of about 11.25 MHz due to the electromagnetic interaction between the cavity resonator and the blood filled plastic tube inserted into the cavity. This proposed system provides a unique approach for real time noninvasive and contactless glucose monitoring.