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.