Rfid System, Gate Arrangement with Rfid System and Method of Detecting Transponders

• US 20080252420A1
• Filed: 02/01/2006
• Published: 10/16/2008
• Est. Priority Date: 02/07/2005
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: NXP B.V. (NXP Semiconductors NV)
• Inventors: Scherabon, Christian
• Granted Patent: US 8,212,678 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• 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 5/77 for interrogation
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

With an RFID system for communicating between reading units (R1, R2) and transponders (T1, T2) in at least two different scan areas (S1, S2), wherein at least one reading unit (R1, R2) and at least one antenna (A1-A4, B1-B4) communicating with the reading unit are allocated to each scan area (S1, S2) for the radiation of electromagnetic signals (EA1-EA4, EB1-EB4) in the scan area (S1, S2), the antennas (A1-A4, B1-B4) are designed in such a way that at least one antenna (A1, A3) of a scan area (S1) has a different polarization and/or a different polarization rotation direction relative to at least one antenna (B2, B4) of another scan area (S2).

Claims

1. An RFID system for communicating between reading units and transponders in at least two different scan areas, wherein at least one reading unit and at least one antenna communicating with the reading unit are allocated to each scan area for the radiation of electromagnetic signals to the scan, wherein the antennas are so designed that at least one antenna of one scan area has a different polarization and/or different polarization rotation direction relative to at least one antenna of another scan area.

2. An RFID system as claimed in claim 1, wherein at least one antenna of one scan area has a different polarization and/or different polarization rotation direction relative to at least one antenna of one or several scan areas adjacent to said scan area.

3. An RFID system as claimed in claim 1, wherein antennas of different scan areas, whose main radiating directions are turned to each other, have different polarizations and/or different polarization rotation directions.

4. An RFID system as claimed in claim 1, wherein the different polarizations and/or polarization rotation directions of the antennas are selected from circular polarization of different rotation direction;

elliptical polarization in different position of the ellipse main axis, optionally with different polarization rotation direction;

circular polarization and elliptical polarization, optional with different polarization rotation direction.

5. An RFID system as claimed in claim 1, wherein the antennas are designed as patch antennas.

6. A gate arrangement comprising at least two gates, wherein each gate has a scan area through which items provided with transponders can be moved, wherein the gate arrangement has an RFID system as claimed in claim 1.

7. A method of detecting transponders in at least two different scan areas, wherein at least one reading unit communicating with the transponders and at least one antenna communicating with the reading unit are allocated to each scan area for the radiation of electromagnetic signals to the scan area wherein electromagnetic signals radiated to a scan area have a different polarization and/or a different polarization rotation direction relative to electromagnetic signals radiated to another scan area.

8. A method as claimed in claim 7, wherein electromagnetic signals radiated to one scan area have a different polarization and/or a different polarization rotation direction relative to electromagnetic signals radiated to one or several scan areas adjacent to the said scan area.

9. A method as claimed in claim 7, wherein the electromagnetic signals radiated over antennas of different scan areas whose main radiating directions are turned to each other, have different polarizations and/or different polarization rotation directions.

10. A method as claimed in claim 7, wherein the different polarizations or polarization rotation directions respectively of radiated electromagnetic signals are selected from circular polarization of different rotation direction;

elliptical polarization in different position of the ellipse main axis, optionally with different polarization rotation direction;

or circular polarization and elliptical polarization, optionally with different polarization rotation direction.