Method for determining the humidity and density of a dielectric material

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, the quantities resonant frequency, resonator quality and resonance maximum are determined and the bandwidth is calculated therefrom, and wherein the quantities resonant frequency, resonator quality, and resonance maximum of the resonator are determined by:
• at least one of arbitrarily or randomly selecting a set of the points for which a number is an integer multiple of three and is at least six, and splitting up the point set into three equally sized groups;
• for each combination of three points, wherein each point comes from a different one of the groups, solving a first system of equations to obtain resonant parameters, the system consisting of three equations of the analytic resonance curve valid for said three points;
• and
• for each of the resonant parameters, creating an average of values calculated at said combinations.