Microwave measurement of wood anisotropy

This paper reports the findings of an experimental study on wood anisotropy measured using a free space horn/lens antenna system. A brief theoretical overview of the plane wave propagation through an anisotropic material introduces the parameters which are measured in this study. Measured data are presented and analyzed for a wide range of samples, introducing a categorization with attempt to simplify the problem posed by the great variability in material structure. We aim to demonstrate that the microwave signal transmitted through the wood is very `information rich´ and that different polarizations as well as angles of observations may provide us with better insight in the wood structure and its properties of interest for nondestructive industrial inspection.