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Updated: Jan 29, 2026

In Situ Soil Moisture Sensors in Undisturbed Soils
Published on: November 18, 2022
Novel Spiral and Embracing IDE Capacitive Sensors for In Situ Measurement of Soil Moisture
Yu Xu1, Yiqi He1, Xizheng Li1
1College of Physical and Electronic Engineering, Xingyang Normal University, Nan Hu Road 237, Xingyang 464099, China.
Abstract:
A novel capacitive interdigital electrode (IDE) sensor for the in-situ measurement of soil moisture is presented. Two planar electrode configurations, spiral and embracing, were designed and evaluated through modeling, simulation, fabrication, and experimental validation. Compared with conventional circular and square electrodes, the proposed structures exhibited higher sensitivity and greater electric field penetration, with the spiral configuration offering the advantage of easier fabrication. The experimental results demonstrated that the calibrated spiral IDE sensor achieved a coefficient of determination (R2) of 0.9976 and a mean squared error (MSE) of 0.859, indicating good stability and repeatability over the tested period. Furthermore, comparison with a commercial moisture sensor showed that the proposed sensor reached a higher R2 value of 0.9995, exhibiting closer agreement with gravimetric measurements. These findings confirm that the developed sensor holds strong potential for in situ monitoring of soil moisture and can provide valuable technical support for landslide monitoring and prevention.
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