Frequency and temperature behavior of density-independent calibration functions for on-line moisture sensing in grain and seed

摘要

The frequency and temperature behavior of two density-independent permittivity-based calibration functions are discussed for a microwave moisture sensor operating on the principle of free-space permittivity measurement. Frequency selection and the need for temperature compensation for optimum use of the instrument capabilities are demonstrated through permittivity measurements on wheat and soybeans over wide ranges of frequency, temperature, bulk density and moisture content.