RFID READER COMPENSATING LEAKAGE SIGNAL AND COMPENSATING METHOD THEREOF

• US 20090068957A1
• Filed: 09/05/2008
• Published: 03/12/2009
• Est. Priority Date: 09/07/2007
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: KOO, JI-HUN, Nam, Kuang-Woo, Kim, In-Hyuk, Min, Young-Hoon, Koo, Si-Gyoung, Tikhov, Yuri, Song, Il-Jong
• Application Number:
  US12/205,401
• Publication Number:
  US 20090068957A1
• Time in Patent Office: Days
• US Class Current: 455/67.140
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H04B 5/0031 for data transfer
• CPC Class Codes: H04B 5/0062 in RFID [Radio Frequency Identification] Systems
• CPC Class Codes: H04B 5/02 using transceiver
• CPC Class Codes: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/72 for local intradevice communication
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

A radio frequency identification (RFID) reader includes a transmitter generating a transmission signal for transmission to a tag, a receiver receiving a response signal from the tag, a leakage compensator compensating a leakage signal leaked from the transmitter to the receiver in response to a leakage control signal, and a control unit performing a leakage test operation by applying a test signal to the transmitter, and calculating and storing a leakage parameter for generating the leakage control signal using a level difference of the test signal and a level difference of a test leakage signal leaked to the receiver.

Claims

1. A radio frequency identification (RFID) reader, comprising:

a transmitter generating a transmission signal for transmission to a tag;

a receiver receiving a response signal from the tag;

a control unit applying a test signal to the transmitter to generate a test leakage signal, and generating a leakage control signal based on a difference of the test signal and the test leakage signal; and

a leakage compensator compensating signal leakage from the transmitter in response to the leakage control signal.

2. The RFID reader of claim 1, wherein the control unit further generates and stores a leakage parameter.

3. The RFID reader of claim 1, wherein the test signal is a square wave in which a cycle has a high-level section and a low-level section, the high-level section being higher than a reference level, and the low-level section being lower than the reference level.

4. The RFID reader of claim 3, wherein the test signal includes a plurality of cycles.

5. The RFID reader of claim 4, wherein the control unit calculates the leakage parameter using a mean value of a level difference of each cycle of the test leakage signal and a mean value of a level difference of each cycle of the test signal.

6. The RFID reader of claim 1, wherein the transmitter and the receiver are connected to a common antenna through a directional coupler.

7. The RFID reader of claim 1, wherein the transmitter comprises a transmitting antenna, and the receiver comprises a receiving antenna.

8. The RFID reader of claim 1, wherein the leakage compensator changes an amplitude and a phase of the transmission signal, and compensates the leakage signal using the changed transmission signal.

9. The RFID reader of claim 8, wherein the leakage parameter indicates an amplitude ratio between the transmission signal and the leakage signal, and a phase difference between the transmission signal and the leakage signal.

10. The RFID reader of claim 8, wherein the leakage compensator further comprises a variable amplitude controller controlling an amplitude of the transmission signal, and a variable phase shifter phase-shifting a phase of the transmission signal.

11. A method for compensating a leakage signal of an RFID reader including a transmitter generating a transmission signal for transmission to a tag, a receiver receiving a response signal from the tag, and a leakage compensator compensating a leakage signal leaked from the transmitter to the receiver,

the method comprising:

applying a test signal to the transmitter, and calculating and storing a leakage parameter using a level difference of the test signal and a level difference of a test leakage signal leaked to the receiver; and

compensating the leakage signal using the leakage parameter.

12. The method of claim 11, wherein the leakage parameter is stored in a register.

13. The method of claim 11, wherein the test signal is a square wave in which a cycle has a high-level section and a low-level section, the high-level section being higher than a reference level, and the low-level section being lower than the reference level.

14. The method of claim 13, wherein the test signal includes a plurality of cycles.

15. The method of claim 14, wherein the leakage parameter is calculated using a mean value of a level difference of each cycle of the test leakage signal and a mean value of a level difference of each cycle of the test signal.

16. The method of claim 11, wherein the leakage compensator changes an amplitude and a phase of the transmission signal, and compensates the leakage signal using the changed transmission signal.

17. The method of claim 16, wherein the leakage parameter indicates an amplitude ratio between the transmission signal and the leakage signal, and a phase difference between the transmission signal and the leakage signal.

18. A method of compensating a leakage signal of an RFID reader,

the RFID reader comprising:

a transmitter selecting one of a plurality of channels, and transmitting a transmission signal to a tag through an antenna using the selected channel;

a receiver receiving a response signal corresponding to the transmission signal from the tag;

a leakage compensator responding to a leakage control signal to compensate the leakage signal reflected from the antenna and leaked to the receiver,

the method comprising;

applying a test signal corresponding to a frequency of each of the plurality of channels to the antenna, receiving a test leakage signal reflected from the antenna, measuring a return loss using the test signal and the test leakage signal, and calculating and storing leakage parameters corresponding to each of the plurality of channels using the return loss; and

generating the leakage control signal using the leakage parameters.

19. The method of claim 18, wherein the leakage parameters are stored in a register.

20. The method of claim 18, wherein the generating of the leakage control signal comprises:

transmitting the transmission signal using the selected channel;

receiving the response signal from the tag; and

generating the leakage control signal using the leakage parameter corresponding to the selected channel.