RFID reader and active tag

• US 20060279458A1
• Filed: 06/14/2005
• Published: 12/14/2006
• Est. Priority Date: 06/03/2004
• Status: Active Grant

• Current Assignee: Farrokh Mohamadi
• Original Assignee: Farrokh Mohamadi
• Inventors: Mohamadi, Farrokh
• Granted Patent: US 7,432,855 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

In one embodiment, an RFID reader and active tag (RAT) includes: a first beam forming means for interrogating a plurality of RFID tags using at least a first set of two antennas coupled to a first fixed phase feed network, the beam forming means being configured to adjust gains in the first fixed phase feed network to scan with respect to the plurality of RFID tags; and a second beam forming means for uploading RFID data from the interrogated plurality of RFID tags to an external access point using at least a second set of two antennas coupled to a second fixed phase feed network, the beam forming means being configured to adjust gains in the second fixed phase feed network to direct its RF beam at the external access point.

Claims

1. An RFID reader and active tag (RAT), comprising:

a first plurality of antennas;

a first fixed phase variable gain beam forming interface coupled to the first plurality of antennas;

a wireless interface configured to communicate through the first fixed phase variable gain beam forming interface with an access point;

a second plurality of antennas;

a second fixed phase variable gain beam forming interface coupled to the second plurality of antennas; and

an RFID interface configured to interrogate RFID tags through the second fixed phase variable gain beam forming interface.

2. The RAT of claim 1, further comprising a logic engine to control the beam forming provided by the first and second beam forming interfaces.

3. The RAT of claim 1, wherein the wireless interface is an IEEE 802.11 interface.

4. The RAT of claim 1, wherein the second plurality of antennas are removably attached to the RFID reader and active tag.

5. The RAT of claim 4, wherein each antenna in the second plurality of antennas comprises a monopole antenna.

6. The RAT of claim 5, wherein each monopole antenna is contained with an insulating layer having an angular cross section such that the monopole antenna can engage an angular edge of a container.

7. The RAT of claim 6, wherein an outer edge of the insulating layer is covered by a conducting reflecting layer and wherein an inner edge of the insulating layer is covered by an adhesive layer.

8. The RAT of claim 7, wherein the conducting reflecting layer comprises aluminum foil and the adhesive layer comprises VELCRO adhesive.

9. The RAT of claim 1, wherein a fixed phase feed network coupling the second beam forming interface to the second plurality of antennas is configured to feed each antenna in the second plurality of antennas in phase with the remaining antennas.

10. The RAT of claim 1, wherein the first plurality of antennas comprises a first and a second antenna, and wherein a fixed phase feed network coupling the first beam forming interface to the first plurality of antennas is configured to feed the first antenna substantially ninety degrees out of phase with the remaining antennas.

11. The RAT of claim 1, further comprising a PCMCIA card, wherein the first plurality of antennas are integrated with the PCMCIA card.

12. A method, comprising:

beam forming to scan through a plurality of items to interrogate a corresponding plurality of RFID tags so as to obtain RFID data;

storing the RFID data in a memory; and

uploading the stored RFID data to an external access point.

13. The method of claim 12, wherein the beam forming comprises adjusting the channel gains of a fixed phase feed feeding a first plurality of antennas.

14. The method of claim 12, wherein the uploading of the stored RFID data is performed through a plurality of antennas using beam forming so as to direct an RF beam at the external access point.

15. The method of claim 14, wherein the external access point is an IEEE 802.11 access point.

16. An RFID reader and active tag (RAT), comprising:

a first beam forming means for interrogating a plurality of RFID tags using at least a first set of two antennas coupled to a first fixed phase feed network, the beam forming means being configured to adjust gains in the first fixed phase feed network to scan with respect to the plurality of RFID tags; and

a second beam forming means for uploading RFID data from the interrogated plurality of RFID tags to an external access point using at least a second set of two antennas coupled to a second fixed phase feed network, the beam forming means being configured to adjust gains in the second fixed phase feed network to direct its RF beam at the external access point.