Simple Instrument for Moisture Measurement in Grain by Free-Space Microwave Transmission
2006
Kim, K.B. | Kim, J.H. | Lee, C.J. | Noh, S.H. | Kim, M.S.
A simple microwave moisture meter for grain was introduced with reduction of the size and volume of the instrument by means of 2 x 2 microstrip patch array antennas. The attenuation and phase shift produced by Korean short-grain rough rice, brown rice, and barley were analyzed to estimate the relationships between moisture density in the grain and the attenuation and phase shift. Second- and third-order polynomial attenuation models were a better measure of moisture density than were phase shift models. A grain moisture meter using microwave attenuation in free-space was constructed. A prototype grain moisture meter consisting of a 10.5 GHz oscillator, patch array antennas, isolator, detector, and digital voltmeter provided a coefficient of determination, standard error of prediction (SEP), and bias of 0.975, 0.62% moisture content, and -0.05% moisture content, respectively.
显示更多 [+] 显示较少 [-]