Design and Simulation of Capacitive Sensors of Various Geometries for Drop based Quality Analysis of Beverages

Capacitive sensors are easy to fabricate, compact in size, economical, and quite efficient in the detection of impurities and adulteration in fluids (like milk, fruit, vegetable juices, etc.) and other consumable food items. The change in the dielectric constant of consumable fluids due to the mixing of adulterants and preservatives can be utilized to detect the extent of adulteration and hence its quality. The change in a dielectric property of a fluid can be reflected in terms of the change in capacitance values utilizing these highly economical and compact capacitive sensors. In this work, a simulation of parallel plate capacitive sensors of different sizes and configurations using copper material is done. Also, cross capacitive sensor with brass material is simulated in various shapes of electrodes with different dimensions. The shift in the base value of capacitances due to a milk sample drop is acquired for the sensors to comment on their sensitivity. It is found that for the cross-capacitive sensor if the dimension is close to the size of the drop the maximum change in capacitance is obtained. For the parallel plate sensor by changing the size of the electrodes the base value and sensitivity change to an extent till the optimum value of dimensions for which sensitivity is maximum.