APPARATUS AND METHOD FOR OFFSETTING TRANSMISSION LEAKAGE SIGNAL OF RFID READER USING INJECTION LOCKED OSCILLATOR (ILO)

• US 20150097031A1
• Filed: 10/07/2014
• Published: 04/09/2015
• Est. Priority Date: 10/07/2013
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: YANG, Hoe Sung, MO, Sang Hyun
• Granted Patent: US 9,122,938 B2
• Time in Patent Office: Days
• US Class Current: 235/439
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: G06K 7/10198 setting parameters for the interrogator, e.g. programming parameters and operating modes
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A transmission leakage signal offset apparatus of a radio frequency identification (RFID) reader is disclosed. The transmission leakage signal offset apparatus may include a signal divider to divide a received signal of the RFID reader, the received signal including a transmission leakage signal, and to transmit the divided received signal to a signal combiner and an injection locked oscillator (ILO); a signal synchronizer to synchronize a phase of the ILO with a phase of the transmission leakage signal; a phase controller to control a phase difference between the received signal of the RFID reader and an output signal of the ILO; and a signal combiner to combine the received signal of the RFID reader and the output signal of the ILO, between which the phase difference is controlled.

Claims

1. A transmission leakage signal offset apparatus of a radio frequency identification (RFID) reader, the transmission leakage signal offset apparatus comprising:

a signal divider to divide a received signal of the RFID reader, the received signal including a transmission leakage signal, and to transmit the divided received signal to a signal combiner and an injection locked oscillator (ILO);

a signal synchronizer to synchronize a phase of the ILO with a phase of the transmission leakage signal;

a phase controller to control a phase difference between the received signal of the RFID reader and an output signal of the ILO; and

a signal combiner to combine the received signal of the RFID reader and the output signal of the ILO, between which the phase difference is controlled.

2. The transmission leakage signal offset apparatus of claim 1, wherein the signal divider divides the received signal of the RFID reader based on whether a phase shift is present with respect to the received signal of the RFID signal including the transmission leakage signal.

3. The transmission leakage signal offset apparatus of claim 1, wherein the phase controller controls a phase of the divided received signal of the RFID reader and a phase of the output signal of the ILO so that the phase difference the divided received signal and the output signal becomes approximately 180 degrees.

4. The transmission leakage signal offset apparatus of claim 1, wherein the phase controller controls a phase of the divided received signal of the RFID reader to be approximately 180 degrees and a phase of the output signal of the ILO to be approximately 0 degrees.

5. The transmission leakage signal offset apparatus of claim 1, wherein the phase controller controls a phase of the divided received signal of the RFID reader to be approximately 0 degrees and a phase of the output signal of the ILO to be approximately 180 degrees.

6. The transmission leakage signal offset apparatus of claim 1, wherein the phase controller controls a phase of the divided received signal of the RFID reader by approximately 90 degrees and a phase of the output signal of the ILO by approximately 90 degrees so that a phase difference between the divided received signal and the output signal becomes approximately 180 degrees.

7. The transmission leakage signal offset apparatus of claim 1, further comprising a power controller to control amplitude of the output signal of the ILO by controlling an output power level of the ILO according to a power level of the transmission leakage signal.

8. The transmission leakage signal offset apparatus of claim 7, wherein the power controller controls amplitude of the output signal of the ILO to be equal to amplitude of the transmission leakage signal.

9. The transmission leakage signal offset apparatus of claim 1, wherein the received signal of the RFID reader, including the transmission leakage signal, comprises a combined signal of the transmission leakage signal flown from a transmitter of the RFID reader and a tag signal received from a tag.

10. The transmission leakage signal offset apparatus of claim 1, wherein the signal divider receives and divides the received signal of the RFID reader including the transmission leakage signal with respect to a signal acquired by combining the received signal of the RFID reader and the output signal of the ILO.

11. A transmission leakage signal offset method of a radio frequency identification (RFID) reader, the transmission leakage signal offset method comprising:

dividing a received signal of the RFID reader, the received signal including a transmission leakage signal, and transmitting the divided received signal to a signal combiner and an injection locked oscillator (ILO);

synchronizing a phase of the ILO with a phase of the transmission leakage signal;

controlling a phase difference between the received signal of the RFID reader and an output signal of the ILO; and

combining the received signal of the RFID reader and the output signal of the ILO, between which the phase difference is controlled.

12. The transmission leakage signal offset method of claim 11, wherein the dividing comprises dividing the received signal of the RFID reader based on whether a phase shift is present with respect to the received signal of the RFID signal including the transmission leakage signal.

13. The transmission leakage signal offset method of claim 11, wherein the controlling comprises controlling a phase of the divided received signal of the RFID reader and a phase of the output signal of the ILO so that the phase difference the divided received signal and the output signal becomes approximately 180 degrees.

14. The transmission leakage signal offset method of claim 11, wherein the controlling comprises controlling a phase of the divided received signal of the RFID reader to be approximately 180 degrees and a phase of the output signal of the ILO to be approximately 0 degrees.

15. The transmission leakage signal offset method of claim 11, wherein the controlling comprises controlling a phase of the divided received signal of the RFID reader to be approximately 0 degrees and a phase of the output signal of the ILO to be approximately 180 degrees.

16. The transmission leakage signal offset method of claim 11, wherein the controlling comprises controlling a phase of the divided received signal of the RFID reader by approximately 90 degrees and a phase of the output signal of the ILO by approximately 90 degrees so that a phase difference between the divided received signal and the output signal becomes approximately 180 degrees.

17. The transmission leakage signal offset method of claim 11, further comprising controlling amplitude of the output signal of the ILO by controlling an output power level of the ILO according to a power level of the transmission leakage signal.

18. The transmission leakage signal offset method of claim 17, wherein the controlling comprises controlling amplitude of the output signal of the ILO to be equal to amplitude of the transmission leakage signal.

19. The transmission leakage signal offset method of claim 11, wherein the received signal of the RFID reader, including the transmission leakage signal, comprises a combined signal of the transmission leakage signal flown from a transmitter of the RFID reader and a tag signal received from a tag.

20. The transmission leakage signal offset method of claim 11, wherein the dividing comprises receiving and dividing the received signal of the RFID reader including the transmission leakage signal with respect to a signal acquired by combining the received signal of the RFID reader and the output signal of the ILO.