METHOD FOR MEASURING MOISTURE WITH MICROWAVE

摘要

PURPOSE:To measure a moisture content without receiving the influence of the fluctuation in the transmission power of a microwave and reflected power by measuring the phase delay in the microwave propagation characteristics of two kinds of different frequencies. CONSTITUTION:The microwave of a frequency f1 from a microwave oscillator 1 is inputted to a phase comparator 4 and is supplied to a material 13 to be measured. The microwave transmitted through the material 13 is received by a receiver 11 and is inputted to a phase comparator 4, by which the phase delay theta1 thereof is detected. A phase dalay theta2 is similarly detected by a phase comparator 7 with respect to the microwave of a frequency f2 as well. The simultaneous equation (I) is solved with the moisture gamma1 in the material to be measured and the mass gamma2 of said material to determine the moisture gamma1 and the mass gamma2 and the moisture content of the material 13 is obtd. from gamma1/gamma2.