Edge Correction in Calculation of Dielectric Constant

When relative permittivity (relative dielectric constant) is calculated based on capacitance data from an unshielded, two-electrode fixture, edge capacitance corrections should be used. Corrections are given in ASTM D150-98 for the case of thin electrodes (such as foil) in several configurations. The ASTM formulas are based on multiple linear regression analysis of data from Scott and Curtis. In this study, a finite-element model of the original measurement setup is developed, and the model is verified against the original data. The model is used to do additional numerical experiments, and these new data are used to extend the range of the original regression formulas.