Measurement of grain moisture content using microwave attenuation at 10.5 GHz and moisture density

The dielectric properties of Korean short-grain rough rice, brown rice and barley with moisture content ranges of 11% to 27%, 11% to 18%, and 11 to 21%, wet basis, respectively, were characterized to develop a prototype grain moisture meter using microwave attenuation at 10.5 GHz and moisture density. A third-order polynomial regression model was proposed to describe the relationship between dielectric properties and moisture density. The prototype grain moisture meter consisted of a dielectric resonator type oscillator of 10.5 GHz, horn antenna, rectangular sample holder, load cell, temperature sensor, detector, and digital voltmeter. The calibration equation for measurement of grain moisture content was developed and estimated with Korean short-grain rough rice (12% to 26%). The coefficient of determination, standard error of prediction (SEP), and bias were 0.986, 0.52% moisture content and 0.07% moisture content, respectively.