MICROWAVE RESONATOR FOR SENSING MOISTURE-CONTENT AND MASS OF SINGLE WHEAT KERNELS

Principles for determining moisture content and mass of individual wheat kernels by microwave resonator measurements are discussed and data are presented showing the application of these principles. By measuring the shift in the resonant frequency and the change in the resonator transmission characteristics when a wheat kernel is inserted into the resonator, moisture content of the kernel may be determined independent of its mass and apparently independent of wheat variety. The same measurement can simultaneously determine the kernel mass. Moisture contents in the range from 10 to 21%, wet basis, were determined with an uncertainty of 0.8% moisture. Uncertainty in the mass determination was less than 1 mg.