Volume optimization of liquids for dielectric permittivity measurements at microwave frequencies

An estimation of an optimum cylindrical volume of some liquids for their accurate dielectric permittivity characterization using an open-ended coaxial probe is presented in this paper. The analysis is based on the simulated electric E-field distribution within the liquids. A criteria is proposed, where the dispersed E-field inside the sample drops to 5% of the maximum power supplied by the coaxial probe. The analysis is carried out at frequency points that lie within the most commonly used range following this technique. Comparisons with suggested values in literature are carried out, showing the differences and accuracy of the results.