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.