Comparative Study of IDC Sensor’s Geometrical Effect, Performance, and Frequency Behaviour with Water Level Detection

Fringe field capacitive sensors with interdigitated electrodes allow non-invasive measurements. The design of the fringing electric field and analytical characteristics of four different geometrical shaped capacitive sensors for water level measurement have been covered in this work. The work aims to explore the effect of the geometrical shape of IDC sensors, compare the performance of all the designed sensors, characterize their frequency behaviour and establish the best suitable sensor for water level measurement. All statistical calculations were undertaken for the goodness of fit for the proposed sensor’s model. The experiments were performed in the laboratory by immersing the sensor inside the container containing still tap water. The result obtained was promising since the measurement of all the proposed sensors fitted the experimental data for a measured frequency range with a satisfactory determination of the coefficient of the R-square value. Archimedean spiral sensor performance is found to be best at all statistical criteria (R-square > 0.99, percent NRMSE < 1.56, standard deviation, and uniformity) for the level measurement. The experimental report shows that the sensitivity of the spiral sensor is 0.0533 to 0.055 nF/cm .