Provided herein is an RFID reader system and method for determining an RFID tag distance. The RFID reader receives a first backscattered signal from an RFID tag in response to transmission of a first RF interrogation signal, and determines a first phase angle of the first backscattered signal. A radio transceiver device receives a second backscattered signal in response to transmission of a second RF interrogation signal, and determines a second phase angle of the second backscattered signal. A main control unit determines a plurality of first distances and a second distance between the RFID reader and the RFID tag based on the first phase angle and the second phase angle, and select one of the plurality of first distances with respect to the determined second distance as a final distance.