A radio frequency identification (RFID) system is described that utilizes a substantially-contiguous conductive shield to shape an electromagnetic field formed by an antenna for communication with RFID tags. The antenna and the conductive shield have substantially planar forms, and may be mounted to a surface of a check-in/check-out area. The conductive shield is positioned around the antenna and within a plane parallel to the antenna, e.g., within the same plane. The conductive shield shapes the electromagnetic field to extend substantially in a direction perpendicular to the antenna, and prevents the electromagnetic field from forming substantially over the conductive shield.