Density-Independent Moisture Metering in Fibrous Materials Using a Double-Cutoff Gunn Oscillator

A new method of density-independent moisture determination with microwaves operating at one single frequeney is developed. It is based on the two-parameter measurement of the complex dielectric constant being composed to a density-independent calibration factor A(psi) which is a function of moisture content psi. As a first application, a double-cutoff Gunn osclllator was built, stabilized by adjacent modes of a single measuring cavity containing the moist fibrous specimen. The technique removes the need for density and sample-size corrections.