Sensor for depth-selective locating of dielectric materials and method of operating such a sensor

The invention relates to a sensor for locating dielectric objects (104), in particular a beam detector to search dielectric objects (104) behind the surface (103) of building materials, comprising a plurality of electrodes (401, 402, 403, 404; 601, 602, 603, 604) having a transmitting electrode system (401, 402, 403; form 602, 603, 604, 605) and a receiving electrode system (404, 601). According to the invention it is proposed that the relative distance of the electrodes (401, 402, 403, 404; 601, 602, 603, 604, 605) is dimensioned in a direction perpendicular to the measurement direction of the sensor so that the capacitive coupling of the coupling paths between the transmitting electrode system and receiving electrode system having different dependencies on the distance of an object to be detected (104) to the sensor. Furthermore, the invention provides methods for operating such a sensor is concerned.