Multistatic antenna configuration for radio frequency identification (RFID) systems

• US 7,554,451 B2
• Filed: 07/25/2007
• Issued: 06/30/2009
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Alien Technology Corporation
• Inventors: Price, John Michael, Carrender, Curtis L.
• Primary Examiner(s): Mullen; Thomas J
• Application Number:
  US11/828,322
• Publication Number:
  US 20070262872A1
• Time in Patent Office: 706 Days
• Field of Search: 340/572.1, 340/572.7, 340/514, 340/515, 340/10.1, 340/10.5, 340/825.49, 342/165, 342/169, 342/126, 342/127, 342/450, 342/465, 455/67.11, 455/78, 455/83
• US Class Current: 340/572.7
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H01Q 3/44 varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element

Abstract

Methods and apparatuses for configuring antennae of radio frequency identification reader systems. In one aspect of an embodiment, a radio frequency identification (RFID) reader system, includes: a receiver; a radio frequency (RF) source for signal transmission; and a switch matrix coupled with the receiver and the radio frequency sources to selectively couple the receiver and the radio frequency source to a plurality of non-collocated antennae. When in a first mode, the switch matrix connects the radio frequency source to a first one of the antennae for signal transmission and the receiver to a second one of the antennae for signal reception; and when in a second mode, the switch matrix connects the first one of the antennae for signal reception and, in one example, the second one or another one of the antennae to the RF source for signal transmission.

Claims

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

at least one antenna;

a radio frequency (RF) source for signal transmission;

a receiver to receive, during a first mode of the reader, a backscattered modulated signal from at least one RFID tag; and

a signal modulator to provide, during a second mode of the reader, a modulated signal emulating an RFID tag, the modulated signal communicating information to another RFID reader.

2. The RFID reader of claim 1, wherein the at least one antenna comprises a plurality of noncollated antennae.

3. The RFID reader of claim 2, further comprising a switch matrix coupled with the reader to selectively couple the receiver, the RF source, and the signal modulator to one of the plurality of non-collocated antennae.

4. The RFID reader of claim 3, wherein when in the first mode, the switch matrix connects a first one of the plurality of non-collated antennae to the RF source to transmit first signals to the at least one RFID tag, and connects a second one of the plurality of non-collated antennae to the receiver to receive the backscattered modulated signal from the at least one RFID tag.

5. The RFID reader of claim 4, wherein when in the second mode, the switch matrix connects a third one of the plurality of non-collated antennae to the signal modulator to modulate a reflection of the first signals and generate second signals that emulate backscatter signals from an RFID tag.

6. The RFID reader of claim 5, wherein when in the second mode, the switch matrix connects the first one of the plurality of non-collated antennae to the receiver to receive the backscattered modulated signal from the at least one RFID tag.

7. The RFID reader of claim 6, further comprising a processor coupled with the signal modulator to perform one or more tests based on the second signals received through the first and second ones of the plurality of non-collated antennae.

8. The RFID reader of claim 5, further comprising a low noise amplifier coupled with the receiver, wherein when in the first mode the switch matrix connects the low noise amplifier to the second one of the antennae for signal reception, and wherein when in the second mode the switch matrix connects the low noise amplifier to the first one of the antennae for signal reception.

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

a plurality of non-collocated antennae;

a radio frequency (RF) source for signal transmission;

a receiver to receive backscattered modulated signals from at least one RFID tag;

a timing circuit coupled with the receiver, wherein the timing circuit is configured to determine a signal propagation delay between at least two of the plurality of antennae; and

a switch matrix coupled with the reader to selectively couple the receiver and the RF source to the plurality of antennae.

10. The RFID reader of claim 9, wherein when in a first mode, the switch matrix connects a first one of the plurality of non-collated antennae to the RF source to transmit signals to the at least one RFID tag, and connects a second one of the plurality of non-collated antennae to the receiver to receive the backscattered modulated signals from the at least one RFID tag.

11. The RFID reader of claim 10, wherein when in a second mode, the switch matrix connects the first one of the plurality of non-collated antennae to the receiver to receive the backscattered modulated signals from the at least one RFID tag, and connects the second one of the plurality of non-collated antennae to the RF source to transmit signals to the at least one RFID tag.

12. The RFID reader of claim 9, further comprising a processor coupled with the timing circuit to determine location information of the at least one RFID tag by calculating a signal propagation delay from one of the plurality of non-collated antennae to another one of the plurality of non-collated antennae via the at least one RFID tag.

13. The RFID reader of claim 12, further comprising a low noise amplifier coupled with the receiver, wherein when in the first mode, the switch matrix connects the low noise amplifier to the one of the antennae for signal reception, and wherein when in the second mode, the switch matrix connects the low noise amplifier to the another one of the antennae for signal reception.