Free Space Transmission Technique for Microwave Detection of Wheat Moisture Content

Moisture content is an essential indicator for assessing wheat quality, which determines the safety of wheat storage. A measurement system based on the principle of microwave transmission method is designed for a fast and non-destructive grain moisture content determination. The detection system mainly consists of the Agilent PNA-X Series Microwave Network Analyzer, the transmitting and receiving horn antennas, the slide rail, and the sample groove. The key idea of this research is to verify the linear relationship between the scattering parameter and the moisture content in a specific frequency range of 2.6-4.0 GHz. The correlation coefficient and root mean square error are used to evaluate the fitting degree of the linear model. The experimental results might provide a new reference for online real-time detection of wheat quality.