Patent ID: 8742898

Claim:
An apparatus for removing a transmission leakage signal in an RFID system including a reader controller that sends a transmission signal to an RFID tag and receives a receiving signal from the RFID tag in order to read tag information, the apparatus comprising: a leakage signal canceller that: receives a portion of the transmission signal; receives the receiving signal including a transmission leakage signal; and performs an adjustment task of generating a cancellation signal according to an adjustment value and the portion of the transmission signal in order to remove the transmission leakage signal from the receiving signal; a controller that: continuously determines whether there is a change of an RF environment in which the RFID tag is installed by using an intensity of the receiving signal, the receiving signal directly received from the leakage signal canceller; controls an operation of the leakage signal canceller by detecting the adjustment value that makes the intensity of the receiving signal less than a reference value, the adjustment detected according to the change of the RF environment; transfers the adjustment value to the leakage signal canceller when it is determined that there is a change in the RF environment; and controls an operation time of the leakage signal canceller according to an on or off control signal input via the reader controller, wherein the leakage signal canceller comprises: a first leakage signal canceller that performs a first instance of the adjustment task to generate the cancellation signal according to the adjustment value and cancels the transmission leakage signal included in the receiving signal; and a second leakage signal canceller that performs a second instance of the adjustment task and outputs the receiving signal without the transmission leakage signal to the controller after the second instance of the adjustment task is performed.