Microwave sensing of quality attributes of agricultural and food products

Highly automated and computerized processes in agricultural and food industries require the development of sensors for continuous measurement and monitoring of quality attributes of agricultural and food products. Microwave dielectric-based sensors are well suited to fulfill such needs because water is a common component of these products, and water has a strong interaction with the electric field at microwave frequencies. Recent advances in calibration methods and availability of reliable and inexpensive microwave components offer an opportunity for the development of a new generation of low-cost microwave sensors for process monitoring and control that will result in significant labor and cost savings in addition to maintaining the desired quality and complying with safety regulations. This is even more relevant in a social and economic environment where consumer awareness is high and new rules and guidelines for labeling and safety standards are put in place. This paper discusses both the development of calibration methods for indirect determination of bulk density and moisture content from measurement of the dielectric properties at a single microwave frequency and development of inexpensive microwave meters for routine characterization of grain, seed, and in-shell peanuts in static and dynamic situations. Accuracy and savings associated with the use of such devices are also covered. © 1998-2012 IEEE.