1.Graduate School of Agriculture,Kyoto University,Kyoto,Japan;2.NTT Microsystem Integration Laboratories,Atsugi,Japan;3.Graduate School of Engineering Science,Osaka University,Toyonaka,Japan
Abstract:
The attenuation coefficients of 100-GHz millimeter waves polarized linearly were measured for cross-cut, quarter-sawn, and
flat-sawn boards of hinoki (Chamaecyparis obtusa) that were 0.2–2.0 cm thick. This was done to examine the applicability of free-wave propagation theory for applying electromagnetic
waves to wood. It was found that the transmittance of a millimeter wave through the specimen boards was lower when the fiber
direction of a board was parallel to the direction of the electric field of the incident wave than when the fiber direction
was perpendicular to the electric field, and there was little difference in the transmittance between the tangential and radial
directions for the former case. These findings can be quantitatively explained by using propagation theory and the dielectric
properties of wood.