A microwave method for on-line determination of bulk density and moisture content of particulate materials

A new method for simultaneous and independent on-line determination of bulk density and moisture content in particulate materials by measurements of the relative complex permittivity is proposed. The bulk density is determined, based on a representation in the complex plane of relative complex permittivity normalized to bulk density. For moisture content determination, a new density-independent function, exclusively dependent on the dielectric properties, is used. Results obtained from measurements on wheat over broad ranges of microwave frequencies, temperatures, densities, and moisture contents are presented.