Dielectric permittivity-water content relationships in woodchips: Particle size and temperature effects

A review of time domain reflectometry (TDR) applications in porous media

“…varying from 96 at -20 ℃ to 88 at 0 ℃ to 80 at 20 ℃) (Kaatze, 1989). Because εw is much greater than the permittivity of solids (e.g., εs varying from 5 to 10 for soil matrix (Robinson, 2004;Robinson and Friedman, 2003), and from 50 to 70 for meat (at temperatures between 15 ℃ and 65 ℃ at a frequency of 2.45GHz) (Nelson and Trabelsi, 2008;Sipahioglu et al, 2003;Tanaka et al, 2000), 1.3 to 4.5 for dry wood (with density between 0.1 and 1.5 g/cm 3 at a frequency of 0.1GHz) (Amato et al, 2019), 2.5 to 7 for dry concrete (McGraw Jr, 2015), air (εair =~1) and ice at high frequencies (εice = ~3.2) (Dirksen and Dasberg, 1993;Friedman, 1998;Miyamoto et al, 2005;Robinson and Friedman, 2003;Roth et al, 1990;Seyfried and Murdock, 1996), θv of a porous media can be estimated based on a calibration relationship between Ka of a porous medium and θv. Example waveforms and Ka values of selected materials are presented in Fig.…”