A Method for the Dielectric Characterization of Liquids Combining Power Laws of Absorbent-Liquid Mixtures

This contribution proposes a method for determining the dielectric properties of a liquid under test (LUT) from the S-Parameters measurements of a microstrip transmission line (TL). The TL is mounted on an absorbent substrate that can be filled with different LUTs. The proposed method uses the TL method for measuring the dielectric properties of the combination of the absorbent substrate and the LUT. The LUT complex permittivity is estimated by combining two mixing rules: one describing the relationship of the absorbent and a known fluid (air) with the union of both, and the other one describing the relationship of the absorbent and the LUT with the union of both. Results show that the proposed method enables the dielectric characterization of liquids achieving an average error of 12.38% and 40.36% in the estimation of the LUT relative permittivity and the loss tangent, respectively, compared to the values found in the literature.