Patent ID: 7680614
Filing Date: 2010-03-16
Classification: G01N

Abstract:
1. A method for determining the humidity and/or density of a dielectric material in a resonator filled with the material, the resonator including a sender and a receiver, the method comprising: emitting a signal by the sender; sweeping a resonance curve of the filled resonator; measuring appropriate signal strength values of the receiver signal at respective different frequencies; determining a resonant frequency and a bandwidth for the filled resonator from points corresponding to the signal strength values of the receiver signal at the respective different frequencies measured; and calculating at least one of humidity or density of the material by solving a second system of equations comprising the resonant frequencies and respective bandwidths of the empty and of the filled resonator and known calibration coefficients of the resonator, wherein, from the points for determining the bandwidth of the filled resonator, cut-off frequencies are determined and the resonant frequency and the bandwidth are calculated therefrom, and wherein the cut-off frequencies of the resonator are determined by: