RFID READER OUTPUT CONTROL APPARATUS AND METHOD

摘要

An apparatus and method is provided for determining if an object is within a maximum radius for reading an RFID marker from an RFID reader, and controlling the RF output power level of the RFID reader based upon the measured SWR of the transmitted RF signal. The RFID interrogation signal is transmitted at a preset output power level. A comparison is made between the forward and reflected RF signal to determine the SWR. The transmitter output power level of the RFID reader is then adjusted as a function of the SWR such that the output power level is set high when the SWR is high, and set low when the SWR is low.