Measurement of moisture content of Malaysian timber using a free-space technique / Sanadi Zainol

From dielectric constant and loss tangent data, characteristics of timbers such as moisture content and slope of the grain can be measured. Microwave nondestructive testing was used in this experiment to obtain the dielectric constants and loss tangents. Malaysian timbers: Light red meranti, Yellow meranti and keruing were used. Wiltron Vector Network Analyzer, a pair of spot-focusing horn lens antenna, coaxial cables, transitions and a printer were the equipment used in this experiment. A free-space microwave measurement system was used for reflection coefficient measurements of metal-backed specimens in frequency range of 7.5 GHz to 14 GHz. The dielectric constant and loss tangent were calculated when the grain angle of the sample was parallel and perpendicular to the polarization of electric field intensity, E. From the result of dielectric constant, moisture content of the wood can be calculated, by using dielectric mixture theory.