A sensor for measuring the dielectric constant of a test object

摘要

The invention disclosed enables sensing of the electrical permittivity of an object. A sensor is provided that includes a dielectric layer that presents a surface defining the base of a volume in which a test object may be placed and an electrically active layer beneath the dielectric layer, comprising a first set of electrodes that extend in a first direction and a second set of electrodes that extend in a second direction that is perpendicular to the first direction. By applying a signal to a first electrode in said first set of electrodes, an electric field is generated that extends outside of the sensor. An output signal is then produced in a second electrode by capacitive coupling between the first electrode and the second electrode. The electrical permittivity of the volume above the first receiver electrode is then determined based on the output signal in said second electrode.