A radio frequency identification (RFID) system includes a plurality of
RFID tags each having adjustable tag resonant frequency, and an RFID
reader configured to transmit interrogation and change frequency RF
signals. The interrogation and change frequency RF signals are
transmitted at the current tag resonant frequency. The plurality of RFID
tags modify the tag resonant frequency to a new tag resonant frequency in
response to the change frequency RF signals. RFID tag identification
rates may be enhanced by interrogating the plurality of RFID tags at the
tag resonant frequency for a dwell time, receiving response RF signals,
determining a new tag resonant frequency, and transmitting a change
frequency RF signal that causes the RFID tags to change the tag resonant
frequency to the new tag resonant frequency. The new resonant frequency
may be based on the number of received responses.