Investigation of interdigital sensor geometry for oil quality measurement

The paper aims to optimize the geometry of an interdigital electrodes (IDE) used as a capacitive sensor for the quality evaluation of oils. The dielectric constant of an edible oil depends on its quality and composition, it is usually in the range between 2.9 and 3.1 and slightly changes if the composition or the quality changes. Since the change is very small it's very important to use a measurement setup which guarantees the detection of this small change. For the sensor geometry should be optimized to provide higher linearity and sensitivity to the change of the dielectric constant. The results show that the interdigital electrodes sensor can provide good sensitivity to the change of the dielectric constant, 6 pF capacitance change for a 0.1 dielectric constant change.