An RF Sensor for Monitoring the Moisture Content of Bean Grains

Aiming to monitor the moisture content of bean grains, this paper presents an RF sensor, based on the variation of the resonance frequency of a DGS-matryoshka. The design equations are described, and a prototype was manufactured and used to measure the moisture content of four bean grain samples. Sample preparation and measurement procedure are detailed. The results achieved are discussed, obtaining a rate of -16.88 MHz/ΔU%. By utilizing a low-cost portable VNA, the proposed sensor is suitable for both laboratory and field applications. While a more rigorous statistical analysis is necessary, including a larger number of samples, the initial results are promising and support the continuation of this research.