Dynamic measurements of moisture content using microwave signal and its verification

This paper describes a dynamic method to measure the moisture content of grains such as rice and wheat. The proposed method does not require the value of bulk density or mass of the grains. Instead, it uses the attenuation and phase shift of the microwave signal through a microstrip transmission line. The static and dynamic measurements were performed for rice samples having different moisture contents from 11 % to 19 %. The results of the dynamic measurement showed close agreement with those of the static measurement. In addition, the ratio of amplitude change and phase shift is linearly dependent on the moisture content of the rice for both static and dynamic measurements.