Characterization of fringing electric field soil moisture sensor to measure volumetric water content (VWC)

This project aims to research and analyze design of fringing electric field (FEF) soil moisture sensor. Fringing electric field (FEF) sensors are usually used to detect the presence of a material or estimate the concentration of a material. Regarding to their principle, fringing electric field (FEF) sensors can be used as a tool in agriculture field to monitor volumetric water content (VWC) of soil. There are no standard analytical models for FEF sensors. The design parameters such as sensor geometry affect the performance of fringing electric field (FEF) sensors. This research concentrate to the effect of the electrode width, number of electrode and whether there have or no ground. The FEF sensors are simulated using Finite Element Method Magnetic (FEMM). Based from the simulation results, selected design of the FEF soil moisture sensors have been fabricated using printed circuit board, PCB technology. The actual test is done by measure the capacitance value using LCR meter. Test results obtained are then compared with FEMM simulations. The comparison proves that the addition of shielding electrodes and ground electrode at the backplane can improve the penetration depth of FEF sensors. The increasing number electrode, small gaps between electrodes and small electrode width make the sensor more sensitive to presence moisture