A near field radio frequency communication system comprising a master RFID/USN device communicating with a slave RFID/USN device,wherein: the master RFID/USN device comprising a plurality of antennas (101, 102, 103, 104) for sequentially transmitting an energy signal, and means for dividing a coverage area of the master RFID/USN device into a plurality of areas (A, B, C, D) respectively corresponding to the antennas (101, 102, 103, 104); and the slave RFID/USN device comprising means for generating a first power using the transmitted energy signal, the slave RFID/USN device comprises means for detecting a power level of the first power of said energy signal, and means for transmitting an information created based on the power level to the master RFID/USN device, wherein the master RFID/USN device comprises means for receiving the information from the slave RFID/USN device, means for creating a first position information representing information related to a direction in one of the divided areas corresponding to the one of the antennas (101, 102, 103, 104), and means for creating a second position information related to a distance in the one of the divided areas representing whether the slave RFID/USN device is positioned in the one of the divided areas (A, B, C, D), and wherein a position of the slave RFID/USN device is determined by the first position information of the slave RFID/USN device and the second position information of the slave RFID/USN device, and a tag coordinate information of the slave RFID/USN device, characterized in that the information comprises a tag identification information and a tag information, or a waiting state information, and wherein the slave RFID/USN device is configured to operate in a wake-up mode by driving a power supply to transmit a tag identification information and a tag information when the power level of the first power exceeds a reference value, the slave RFID/USN device is configured to operate in a sleep mode to transmit a waiting state information when the power level of the first power is less than or equal to the reference value, wherein the master RFID/USN device is configured to create the second position information representing that the slave RFID/USN device is positioned in the one of the divided areas when the tag identification information and the tag information are received, and the master RFID/USN device comprises means to create the second position information representing that the slave RFID/USN device is positioned outside the one of the divided areas when the waiting state information is received, and wherein a management computer is configured to determine the position of the slave RFID/USN device by the first position information of the slave RFID/USN device, the second position information of the slave RFID/USN device and the tag coordinate information which is matched with a reader coordinate information which is a coordinate information of the master RFID/USN device. the master RFID/USN device comprising a plurality of antennas (101, 102, 103, 104) for sequentially transmitting an energy signal, and means for dividing a coverage area of the master RFID/USN device into a plurality of areas (A, B, C, D) respectively corresponding to the antennas (101, 102, 103, 104); and the slave RFID/USN device comprising means for generating a first power using the transmitted energy signal, the slave RFID/USN device comprises means for detecting a power level of the first power of said energy signal, and means for transmitting an information created based on the power level to the master RFID/USN device,