Sensor for Measuring the Moisture Content and the Mass Per Unit Area of Veneer

A sensor for measuring the moisture content and mass per unit area of some sheetlike material has been constructed. It is a stripline resonator with two center conductors. The sensor is designed for non-contact measurements and it tolerates moderate movements of the sheet perpendicularly to the plane of the sheet to be measured. It is also designed to have high sensitivity even for thin sheets. The sensor has been applied to measuring the moisture content and mass per unit area of veneer sheets, both undried (green veneer) and dried. The resonance frequency of the sensors used was about 350 MHz. Results obtained in the laboratory and in the factory are reported.