Patent ID: 7969313

Claim:
A radio frequency identification (RFID) system, comprising: a first RFID device to transmit wireless interrogation signals, wherein the first RFID device has a first antenna and a second antenna wherein the first antenna is adapted to transmit signals and the second antenna is adapted to receive signals; a second RFID device having a communication circuitry, a first loop antenna and a second antenna configured to operate at a plurality of frequencies, a first frequency of the frequencies being at least twice a second frequency of the frequencies, wherein in response to the interrogation signals, the second RFID device is to use one of the first loop antenna and the second antenna to provide identification signals, at a frequency transmitted by the first RFID device, that are modulated backscatter return signals, the identification signals identifying the second RFID device to the first RFID device; wherein the second RFID device comprises a transmitter configured to communicate with the first RFID device in one of a first communication mode and a second communication mode determined by the first RFID device, wherein in accordance with the first communication mode the transmitter modulates an RF field generated by the second RFID device and in accordance with the second communication mode the transmitter modulates an RF field generated by the first RFID device.