Design, realization, and experimental characterization of an admittance cell for low-frequency dielectric permittivity measurements on liquids

In this work, 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 be easily connected to any LCR meter (even a two-terminal one) employing traditional test fixtures for axial/radial devices. Additionally, 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 non-ionic liquid materials. The results show that the accuracy is comparable with the typical measurement accuracy achievable, at much higher costs, when using commercial solutions.