| During the process of production, processing, storage and transportation, there are strict requirements ongrain moisture content. Nowadays food security has become one of the important factor in a country’s stabledevelopment. The social and economical significance of the grain moisture content rapid determination is veryimportant. At present, the methods of measuring grain moisture content are wide varieties. Differentmeasurement method has its own advantage, limitation and applicability. This article is proceeded with thetheory of electromagnetic wave propagation mainly. Based on analysis of electromagnetic wave propagation’slaw in grain and find a new method for moisture measurement. This paper is mainly as follows:1. Electromagnetic wave propagation law in grain. The article explores the electromagnetic wavepropagation theory, analyzing the principle of electromagnetic wave propagation in lossy medium, thencombining with dielectric property of grain on high frequency situation. Finally, finding out the transmissioncharacteristics of electromagnetic wave in grain.2. The hardware design of measuring device. This part mainly includes high frequency electromagneticsignal generating circuit,cavity structure design and signal’s receiving and processing circuit. The measurementdevice could collect and analyze different grain water content data and detect the changes of the grain moisturecontent real-time.3. The design and data analysis of experiment. After the experiment equipment has been designed,moisture measuring experiment is carried out for5.0%to35.0%soybeans and corn moisture content. Writingdown the relevant grain moisture physical parameters. After dealing with the relevant data, the data has beenanalyzed with SPSS soft ware and build the model.The experimental results show that this method is fast detection and working state is stabilization. Whenthe moisture content is5.0%to10.0%, maximum error of measurement is0.4%,When the moisture content is10.0%to20.0%, maximum error of measurement is0.7%,When the moisture content is20.0%to30.0%,maximum error of measurement is1.5%,When the moisture content is30.0%to35.0%, maximum error ofmeasurement is2.5%,The lower the grain moisture content, the higher accuracy of measurement. This devicecan meets the needs of the on-line test of grain moisture content measurement. |
