New Calibration Algorithms for Dielectric-Based Microwave Moisture Sensors

New calibration algorithms for determining moisture content in granular and particulate materials from measurement of the dielectric properties at a single microwave frequency are proposed. The algorithms are based on identifying, empirically, correlations between the dielectric properties and the partial densities of water and dry matter of a given material. Both situations, where the bulk density is known or unknown, were considered. Validations of the performance of the new algorithms are presented for grain and seed samples for which the dielectric properties were measured by a free-space transmission technique at 10 GHz and 24 °C.