Design and 3-D electric field simulation of a calculable capacitor

A new calculable capacitor with an operating range of 0.1 pF is being developed at NIST. Reduced uncertainty for displacement measurements, enabled by employing tunable laser based Fabry-Perot interferometers, will allow a considerably more compact design, minimizing errors from mechanical sources. Using 3-D electric field simulations, we have also estimated errors resulting from mechanical imperfections.