Measurement of the refracting index of wood for microwave radiation

Energy Transfer from Electromagnetic Fields to Materials

“…The dielectric constant ε' affects the wave impedance of the space occupied by the dielectric material [14] and causes reflections at the inter-facial boundary between materials due to changes in the wave impedance of the space occupied by the material. These changes in wave impedance also cause a change in the wavelength of the electromagnetic fields inside the dielectric material, compared with the wavelength in air or vacuum [15]. This change in wavelength affects the propagation velocity of the wave within the material.…”

Refraction and absorption of microwaves in wood

“…For each wooden plate with different fibre orientation, the birefringence and the absorption coefficients are determined by the least-squares fit of the transmitted microwave amplitude dependence on the receiver orientation. Although the dielectric properties of wood depend strongly on the moisture content [9] and density of the wood, the experiment is still relevant, as it serves for demonstration rather than for accurate laboratory results. If the plates and the wedge are cut from the same piece of wood, then the results are in good agreement with the theoretical expressions.…”

Drying Stress Relaxation of Wood Subjected to Microwave Radiation

“…Microwave technology has already been widely applied throughout wood industry for over half century. Examples include the technique of wood bending after microwave heating, lumber drying via microwave heating, and pressing systems that use microwave heating (Antti 1992;Antti and Perre 1999;Montoro and Manrique 1999;Wang and Xue 2002;Tu 2007;Prasad and Pandey 2012). And some research has focused on wood structure and water transfer in wood under the microwave heating (Daian 2011;Gašparik and Gaff 2013;Grinchik et al 2015).…”