2. Measurement techniques

2.1 Measuring cell

In some cases, the electric field lines are not uniform at the edge of the sample (dielectric material). The curvature of these lines increases with dielectric thickness for a constant thickness of metal electrodes, while it decreases with decreasing metal electrode thickness for a constant dielectric thickness. When this situation arises, a specific capacitance is measured, which is the sum of the actual material capacitance and the edge effect capacitance (called edge capacitance, C _edge ).

Edge capacitance is additional capacitance caused by non-uniform stray electric field lines at the edge of the sample capacitance. It is therefore necessary to subtract the edge capacitance from the measured...