Measurement of the moisture content with a cylindrical resonating cavity in TM/sub 010/ mode

A new resonating mode has been used in a cylindrical cavity to measure the moisture content and the specific mass of cigarettes. A simple theoretic calculation gives the relation between the sample complex permittivity and the characteristics of the cavity. A model is proposed to extract the moisture content and the specific mass from the complex permittivity. An experimental setup has been demonstrated. It uses a servo-controlled oscillator. This setup is ready to be tried on a production machine.