Complex permittivities and dielectric relaxation of granular activated carbons at microwave frequencies between 0.2 and 26 GHz

Carbonaceous materials are amenable to microwave heating to varying degrees. The primary indicator of susceptibility is the complex permittivity (e*), of which the real component correlates with polarization and the imaginary term represents dielectric loss. For a given material, the complex permittivity is dependent upon both frequency and temperature. Here we report the complex permittivities of three activated carbons of diverse origin over the frequency range from 0.2 to 26 GHz. Dielectric polarization-relaxation phenomena for these materials are also characterized. Measurements were made using a coaxial dielectric probe and vector network analyzer based system across the temperature region between 22 and 190 8C.  2003 Elsevier Science Ltd. All rights reserved.

[1]  B. Nøst,et al.  Dielectric dispersion of composite material , 1992 .

[2]  A. C. Metaxas,et al.  Industrial Microwave Heating , 1988 .

[3]  R. Cole,et al.  Dielectric Relaxation in Glycerol, Propylene Glycol, and n‐Propanol , 1951 .

[4]  D. D. Yue,et al.  Theory of Electric Polarization , 1974 .

[5]  J. Atwater.  Complex permittivities of cyclomaltooligosaccharides (cyclodextrins) over microwave frequencies to 26 GHz. , 2000, Carbohydrate research.

[6]  D. Polder,et al.  The effective permeability of mixtures of solids , 1946 .

[7]  L. Taylor,et al.  Dielectric properties of mixtures , 1965 .

[8]  A. Hippel,et al.  Dielectric Materials and Applications , 1995 .

[9]  R. R. Wheeler,et al.  Microwave Regenerable Air Purification Device , 1996 .

[10]  A. Jonscher.  Dielectric relaxation in solids , 1983 .

[11]  T. Ohgushi,et al.  Dielectric properties of dehydrated NaA zeolite, analyses and calculation of dielectric spectra , 2001 .

[12]  D. A. Dunnett.  Classical Electrodynamics , 2020, Nature.

[13]  A. Stogryn.  The bilocal approximation for the effective dielectric constant of an isotropic random medium , 1984 .

[14]  J. Kong,et al.  Scattering of electromagnetic waves from random media with strong permittivity fluctuations. [with application to atmospheric turbulence effects on microwave remote sensing] , 1981 .

[15]  K. Cole,et al.  Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics , 1941 .

[16]  A. Hippel,et al.  Dielectrics and Waves , 1966 .

[17]  V. Gaiduk.  Dielectric Relaxation and Dynamics of Polar Molecules , 1999 .