Assessment of performance of fringing electric field sensor arrays

Model-based multi-wavelength interdigital dielectrometry parameter estimation algorithms require a good agreement between theory and measurements. Research data indicate that the agreement is high for measurement of the properties of fluid dielectrics or the sensor substrate. However, the non-ideality of the surface contact between the sensor and solid materials creates significant differences between the idealized model and experimental results. One solution to this problem is to evaluate surface contact conditions for every measurement and account for them in software. Two alternative sensor designs are compared in this paper in their ability to provide reliable measurement data that can be used by parameter estimation algorithms. Measurement of dielectric and conduction properties of both fluids and solid dielectrics are considered. It is shown that the distribution of the electric field excitation over the entire multi-wavelength sensor head, as opposed to using separate electrode wavelengths, leads to reduction of errors in parameter estimation.