Complex dielectric properties of macroemulsions using microwave interferometric dielectrometer

Abstract This paper describes an open system microwave interference dielectrometer and emulsion measurements. Simplified algebraic expressions are used to convert sample attenuation and phase shift measurements to permitivity and loss factor values, respectively. The apparatus employs lens focused horns and is readily applicable to either online or laboratory measurements without resorting to cumbersome electric field transmission line analysis. Measurements of permittivity and loss factor for oil-in-water and water-in-oil macroemulsions were made at 23.5 GHz. The results verify and extend in frequency our earlier findings that a dielectric modulus, i.e., the ratio of sample emulsion loss tangent to pure water loss tangent, can be used to characterize both emulsion type and water content over a broad range of frequencies.