Multistatic antenna configuration for radio frequency identification (RFID) systems

• US 8,922,375 B2
• Filed: 12/28/2012
• Issued: 12/30/2014
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Align Technology Incorporated
• Inventors: Carrender, Curtis L., Price, John Michael
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US13/730,035
• Publication Number:
  US 20130113610A1
• Time in Patent Office: 732 Days
• Field of Search: 340/572.4, 340/572.7, 340/8.1, 340/10.1, 340/10.5, 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:

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; and

a timing circuit coupled with the receiver, wherein the timing circuit is configured to determine a plurality of signal propagation timing delays via the at least one RFID tag between a first one of the plurality of antennae and each of the plurality of antennae except the first one based on the backscattered modulated signals; and

a processor coupled with the timing circuit to determine a plurality of signal path lengths between the first one of the plurality of antennae and each of the plurality of antennae except the first one based on the plurality of signal propagation timing delays, the processor to determine a location of the at least one RFID tag based on the plurality of signal path lengths.

2. The RFID reader of claim 1, wherein the plurality of propagation timing delays comprises a first propagation timing delay which is on a first signal path from the first one of the antennae to the at least one RFID tag and then to a second one of the antennae, and a second signal propagation timing delay which is on a second signal path from the first one of the antennae to the at least one RFID tag and then to a third one of the antennae, wherein the first signal path is different from the second signal path.

3. The RFID reader of claim 1, wherein the processor coupled to the timing circuit is to calculate the location of the at least one RFID tag based on the plurality of signal propagation timing delays.

4. The RFID reader of claim 1, wherein the processor coupled with the timing circuit is to determine distance information of the at least one RFID tag by calculating the plurality of signal propagation timing delays.

5. The RFID reader of claim 1, wherein the plurality of signal path lengths comprise a first signal path length between the first one of the antennae and a second one of the antennae, and a second signal path length between the first one of the antennae and a fourth one of the antennae.

6. The RFID reader of claim 1, further comprising a low noise amplifier coupled with the receiver and a second one of the plurality of antennae for signal reception.

7. The RFID reader of claim 1, wherein the plurality of signal propagation timing delays are the timing delays of a first signal that is backscattered by the at least one RFID tag via each of the plurality of antennae except the first one.