177 / 2019-03-24 22:37:15

Design of Small Capacitance Standards Based on Analytical and Simulation Approaches

Small Capacitance Standard,Schwarz-Christoffel Transformation,Fringe Effect,Finite Element Analysis

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In the paper, analytical model and simulation are adopted to design of small capacitance standards based on fused silica. The small capacitance standards is designed with Kelvin equipotential protection structure. The stray capacitance introduced by the air gap between the capacitance eletrode and the Kelvin equipotential protection electrode(guard electrode) will affect the small capacitance value. The analytical model of the capacitor is established and the Schwarz-Christoffel transformation is used to analyze the stray capacitance. By adjusting the size of the air gap between the central electrode and the guard electrode, the electric field line collected by the guard electrode is controllable and usable to predict the final capacitance. The finite element analysis software Ansoft is used to simulate the small capacitance under different air gaps with limited ranges, and the appropriate air gap is recomended for implementing of small capacitance standards.