RFID reader and active tag

• US 7,432,855 B2
• Filed: 06/14/2005
• Issued: 10/07/2008
• Est. Priority Date: 06/03/2004
• Status: Expired due to Fees

• Current Assignee: Farrokh Mohamadi
• Original Assignee: Farrokh Mohamadi
• Inventors: Mohamadi, Farrokh
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/153,019
• Publication Number:
  US 20060279458A1
• Time in Patent Office: 1,211 Days
• Field of Search: 322/2, 342/10, 342/2, 342/368, 342/372
• 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) for a pallet of goods, comprising:

a first antenna aligned with a first edge of the pallet;

a second antenna aligned with a second edge of the pallet, the second antenna being orthogonally aligned with the first antenna;

an RFID interface operable to generate RF transmissions to interrogate RFID tags;

a first fixed phase variable gain beam forming interface coupled to the first antenna and the second antenna and to the RFID interface, the first fixed variable gain interface being operable to independently adjust a set of gains for the RF transmissions from the RFID interface to the antennas so as to steer an interrogating RF transmission throughout the pallet to obtain RFID data from RFID tags within the pallet;

a third antenna; and

a wireless interface configured to communicate through the third antenna with an access point, the wireless interface being operable to transmit the RFID data to the access point.

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

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

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

5. The RAT of claim 4, wherein the first and second antennas are monopole antennas.

6. The RAT of claim 5, wherein each monopole antenna is contained within 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, further comprising a PCMCIA card, wherein the third antenna is integrated with the PCMCIA card.