Method and apparatus for detecting end of response signal on radio frequency identifier tag

A method and a device for detecting EOS(End Of Signal) of a signal responded from an RFID(Radio Frequency IDentification) tag are provided to detect the EOS of a received response signal to transmit a next command signal within a time limit in case that the response signal is received from the RFID tag after a reader of an RFID system transmits the command signal to the RFID tag. An EOS detector(218) measures a variance value while moving a sliding window to the response signal received from the RFID tag, compares the variable value with a threshold, and outputs an EOS flag when count is over a predetermined number by counting that the variance value is smaller than the threshold. A controller(220) obtains the threshold from a section receiving no response signal from the RFID tag based on a continuous wave, provides the threshold to the EOS detector, and makes the next command signal transmitted to the RFID tag if the EOS flag is received from the EOS detector after the response signal is received from the RFID tag. The controller transmits the command signal to the RFID tag and starts a timer for counting a response time of the response signal.