High Precision Capacitive Moisture Sensor for Polymers: Modeling and Experiments

In this work a high precision capacitive moisture sensor for polymers was designed and fabricated. The device is part of a compact, fast, and economic moisture analyzer capable of reaching a similar precision than commercial moisture analyzers based on the Karl Fischer method. The design considerations are described in detail and simulation results are presented showing the relationship between the sensor's geometrical parameters and the sensor's performance. Numerical and analytical works were also carried out to support the capacitor optimization. The designed capacitive moisture sensor satisfies all constrains on sensitivity, sensing volume and reliability of the measurements due to its inherent conformal features. The experimental results of the prototype obtained during laboratory tests are also reported in this paper.