Shielded flat-plate proximity/dielectric properties sensor

摘要

A shielded flat-plate proximity/dielectric properties sensor includes a dielectric substrate leaving a planar configuration and a pair of spaced sensing electrodes mounted on one surface of the substrate. A pair of shield electrodes limit the electric field produced by the sensing electrodes. A first shield electrode on the back of the substrate intercepts field lines behind the sensor to prevent detection of objects from behind the sensor. A second shield electrode co-planar with and between the sensing electrodes intercepts field lines very close to the sensor to prevent the dense electric field near the sensor from dominating measurements of objects within the field.