System for detecting radio-frequency identification tags

The present invention indicates the technology which detects a radio frequency discernment (RFID) tag. For example, the exit control system which detects unauthorized carrying out of the goods from a defense institution is indicated. A series of antennas are installed and a police-inspection passage is generated near the exit of a defense domain. The RFID tag is attached to the defense subject article. Each above-mentioned tag contains the information which identifies the goods attached uniquely, and the status information about whether goods carrying out from an institution is permitted. RF leader outputs an RF signal through an antenna, and generates an electromagnetic field in a police-inspection passage. RF leader outputs RF electric wave to two or more antennas by the distributor / coupler course from a single port. Thus, single RF leader only having one transceiver machine port examines two or more antennas simultaneously. And various kinds of technology in which the above-mentioned RF leader can detect carrying out of unauthorized goods is indicated.