Method and device for measuring grammage (basis weight, mass per unit area) and moisture of a sheet, for example of paper, using dielectric resonators

摘要

A grammage measuring apparatus includes a dielectric resonator (1) which is arranged only at one surface side of a sample (10); a shielding container (4) with which the dielectric resonator (1) is substantially covered except for a sample measuring surface; a microwave excitation device (6,2a) which causes the dielectric resonator (1) to generate an electric field vector; a detection device (8,2b) which detects transmission energy or reflection energy by the dielectric resonator (1); a storage device (12) in which a calibration curve indicating a resonance frequency shift amount for a grammage is stored; and a data processing device (14) which calculates the grammage of a measuring sample from the calibration curve and measurement result of the resonance frequency shift amount of the measuring sample.