Medical electrical measurements utilizing the dielectric properties of blood samples.

Reem Jamal Abbas
Dr. Abbas A. Al-Shalchi
Dr. Jabir S. Aziz

Abstract: The designing of blood glucose instrument needs to have a sensor that has a high sensitivity to variation in glucose level in blood, the instruments were designed and developed through years to implement a high accuracy and a harmless instruments that could be used by the patient without difficulties and gives a good reading for the amount of glucose concentration in blood. This work gives a new design for blood glucose instrument that depends in its work on the electrical properties of blood. In this instrument an electrical sensor is used, which is a capacitive transducer, this sensor or transducer is made of two parallel aluminum plates of dimension 3cm length, 1.6cm width, with a distance of 0.5cm between the plates. Th3 sensor senses the change that happens in dielectric constant when the glucose concentration in blood changes, this change is converted to a digital voltage by using an AC circuit, AC to DC converter and A/D converter, in order to convert it then to a readable value by using a microcontroller. The microcontroller gives the equivalent amount of glucose concentration in blood according to the amount of change in the dielectric constant that is measured by the transducer. From this work it’s found that the dielectric constant of blood is increased with increase in its glucose concentration and this increase is nonlinear. The nonlinearity problem is fixed by using least square technique. According to the results that could be obtained in this work one could say that the capacitive transducer has a good sensitivity to blood glucose concentration change and this proposed technique or instrument could be dependable, easy to use, and could be considered harmless and has low cost.