US Patent 9921246 Capacitive electric-field sensor and method of making same

A capacitive sensor to sense an electric field has a shield tube that extends axially along its own axis and has a first open end, an electric field sensor positioned within the shield tube, a source electrode, and a mass of dielectric insulating material positioned within the shield tube and around the shield tube. The shield tube is formed by a jacket having a plurality of first through openings that each have an area comprised between a minimum of 0.1 mm2 and a maximum of 3 mm2.