Calibration techniques for microwave moisture meters

Microwave moisture meters are used for fast measurement of the water content in organic and inorganic bulk materials like grain, sand, and animal feed. The operating principle is based on the very high relative dielectric permittivity and loss factor of water, so the effective electromagnetic parameters of the tested sample depend highly on the water content. The density of the test sample also influences the measurement results, therefore it should be taken into account in device calibration. This work presents several solutions for correction of the influence of the density on the moisture measurement data.