New electrode for measuring precise high-field dielectric properties of polymeric films

A novel electrode system in which the electric-field disturbance around the main electrode edge is minimized by using a guard film has been proposed. This novel electrode system for measuring the precise high-field dielectric properties of polymeric films was evaluated from measurements of capacity and electric-field analyses. The high field tan δ of LDPE (low-density polyethylene) was measured in the new electrode system. The electric field around the main electrode edge was simulated by the finite-element method. In the new electrode system, the disturbance of the electric field around the main electrode edge was significantly eliminated. Capacity was estimated from the results of the electric-field analyses according to Gauss´ theorem. Capacitance measured by the electrode systems indicated a 3% decrease of the edge effect in the new electrode system as compared to the conventional three-terminal electrode system