Capacitive Fringing Field Sensor Design for Moisture Measurement

Abstract

The fringing field capacitive sensor is described for moisture measurement like soil, food application. Interdigitated electrode capacitive sensor has been utilized in numerous applications at low frequency. A sensor performance was evaluated by monitoring the output capacitance variation with and without moisture content. The variation in capacitance is directly measured by using interface circuit. Switched capacitor dual slope capacitor to digital converter has been utilized as an interface circuit. The interface circuit has been designed and simulated with variable capacitance by sensor performance. Printed circuit board technology is particularly advantageous for realizing this type of sensor by fabricating the interdigitated electrode structures in the patterned Cu foil instead of realizing these type of sensors in various technologies.