Design and fabrication of low-cost capacitive sensors for salinity level detection in water

Abstract

The salinity of water has a negative impact on both climate change as well as human health. Therefore, the in situ monitoring of water salinity is important. Numerous approaches, including electromagnetic inductive sensing, remote sensing, methods based on optical fiber sensors, conductive sensing (capacitive or resistive), can be used to measure the salinity of the water. This work focuses mainly on the design and fabrication of low-cost co-planar interdigitated (IDT) sensors with sensitive fringing field measurement capabilities. IDT sensors with configurations 1-1-1, 1-3-1, 1-7-1, and 1-15-1 were designed and fabricated in this work. The capacitance values for all four configurations decrease proportionally with water salinity, demonstrating a negative linear response in sensors that utilize water salinity levels as the dielectric media.