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The microwave dielectric constants of ceramic dispersions in the polyethylene matrix are studied by five well-known mixture equations in this article. Three ceramic powders of fillers with various dielectric constants at 10 GHz are investigated. The experimental dielectric constant values of the mixtures are compared to the theoretical curves of the five mixing rules. The dielectric constants of pure ceramics are then estimated by these mixing laws from the dielectric constants of composites of various filler concentrations. The theoretical errors of estimations of rules are derived and analyzed. The most adequate mixture law(s) for measuring the dielectric constants of ceramic fillers will be recommended. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2481-2485, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26357 [ABSTRACT FROM AUTHOR]

Abstract: Powder mixture rules derived from the filler particles with the shapes of sphere, cylinder or rod, and lamella or disk with random distributions are studied in this paper. Three ceramic powders of fillers with dielectric constants of 10, 20, and 36, respectively, are adopted. The experimental dielectric constants of ceramic dispersions in the polyethylene matrix at microwave frequency are compared to those obtained by using different mixing laws. The mixing rules are also adopted to estimate the dielectric constants of pure ceramics from the measured dielectric constants of composites with various concentrations. The theory for the error of estimation is studied. In contrast to the traditional concept of obtaining the best curve fitting of mixture rule with the experimental data, this study conclude a very important concept on the powder mixture rule, that is, the most adequate mixture law for estimating the dielectric constants of pure ceramics requires both good curve fitting and potential of less error. [Copyright &y& Elsevier]