It is possible to determine properties of wood using microwave scanning techniques. The purpose of this study was
to verify the measured values from a microwave imaging sensor. Attenuation and phase shift of an electromagnetic
wave transmitted through birch wood were measured and compared with theoretical calculated values. A test piece with
varying thickness was measured with a scanner based on a microwave sensor (Satimo 9.375 GHz) at different temperatures
and moisture contents. The density distribution of the test piece was determined by computer tomography scanning.
The result showed good correspondence between measured and theoretical values. The proportion of noise was
higher at low moisture content due to lower attenuation. There is more noise in attenuation measurement than in measurement
of phase shift. A reason for this could be that wood is an inhomogeneous material in which reflections and
scattering affect attenuation more than phase shift. The microwave scanner has to be calibrated to a known dielectric to
quantify the error in the measurement.
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