ABSTRACT. Physically meaningful theoretical models for dielectric properties based on realistic ceramic microstructures are explored. Various concentrations of cupric oxide and alumina are prepared by physical (ball) mixing and chemical precipitation. The complex permittivity of these composites are accurately measured in a resonant cavity. An exact analytical solution to the TM_mno modes of a cylindrical cavity is used to accurately calculate the dielectric properties based on the resonant frequency and Q-factor of the resonant mode. Initial results found that chemically precipitated composites possess higher dielectric losses than the physically mixed composites. A fractal boundary model and other mixing laws are applied to understand complex permittivity dependence on composition and sample preparation.

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