Microwave sensor for simultaneous and nondestructive determination of moisture content and bulk density of granular materials

A low-cost microwave sensor operating at a single frequency for instantaneous and nondestructive determination of moisture content and bulk density of granular and particulate materials was developed and tested. The sensor operates at a frequency of 5.8 GHz and uses the principle of free-space transmission measurement. Several algorithms were used to determine simultaneously moisture content and bulk density from measurement of attenuation and phase shift through the material and its dielectric properties.