Droplet Detection with Interdigitated Capacitor Sensor

The capacitive sensor designed based on interdigitated capacitor is studied as one of the methods to detect size and speed of droplets, which can be further applied in Lab-on-a-chipl microfluidic systems. The interdigitated capacitors in millimeter regime are studied, analyzed, designed, implemented and measured. The results of both simulation and measurement showed similar capacitance values. Then, the micrometer-scaled sensor is designed for further implementation with the silicon process. The Capsense evaluation board with capacitance to digital reader are used to monitor the capacitance from interdigitated capacitor. The principle to calculate speed and size of the droplets are also provided.