Design, Realization, and Experimental Characterization of an Admittance Cell for Low-Frequency Dielectric Permittivity Measurements on Liquids

Abstract

In this paper, the design, the realization, and the experimental characterization of a parallel-plate admittance cell with no guard ring, to be used for low-frequency dielectric permittivity measurements of liquids, are presented. In contrast to guarded-terminal cells, the proposed admittance cell can easily be connected to any LCR meter (even a two-terminal one) employing traditional test fixtures for axial/radial devices. In addition, the fringing effect is compensated for through a correction factor ( $\alpha $ ) obtained from electromagnetic simulations of the structure, rather than through time-consuming experiments on a number of reference liquids or adopting approximated theoretical formulations. Finally, to verify the suitability of the fabricated admittance cell for low-frequency dielectric spectroscopy and to assess its metrological performance, a set of measurements was carried out on six reference nonionic liquid materials. The results show that the accuracy is comparable with the typical measurement accuracy achievable, at much higher costs, when using commercial solutions.