Antenna system and method for determining a transit of a movable object through a detection plane

Embodiments relate to a concept for determining a transit of a movable object (11) through a detection area within a detection plane (22), comprising providing, by means of at least one exciter antenna (9), an exciting electromagnetic field (12), wherein the exciting electromagnetic field (12) or at least one spatial component thereof has a field strength above a field strength threshold in the detection area, wherein the exciting electromagnetic field (12) is capable of exciting the movable object (11) to emit an electromagnetic response signal (44a, 44b) comprising information on a position of the movable object (11); and receiving, by means of at least one sensor antenna (4a-d) comprising a magnetic core (31), the electromagnetic response signal (44a, 44b), wherein the at least one magnetic core (31) is positioned in a region (27) of the exciting electromagnetic field (12) where the field strength of the exciting electromagnetic field or the at least one spatial component thereof is below the field strength threshold.