Multistatic Antenna Configuration For Radio Frequencey Identification (RFID) Systems

• US 20090231105A1
• Filed: 05/29/2009
• Published: 09/17/2009
• Est. Priority Date: 03/01/2005
• Status: Active Grant

• Current Assignee: RUIZHANG TECHNOLOGY LIMITED COMPANY
• Original Assignee: Curtis L. Carrender, John Michael Price
• Inventors: Carrender, Curtis L., Price, John Michael
• Granted Patent: US 8,350,701 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• 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 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 signal propagation delay between at least two of the plurality of antennae.

2. The RFID reader of claim 1, wherein the plurality of antennae are non-collated antennae.

3. The RFID reader of claim 2, 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 noncollated antennae to another one of the plurality of non-collated antennae via the at least one RFID tag.

4. The RFID reader of claim 2, further comprising a processor coupled with the timing circuit to determine distance information of the at least one RFID tag by calculating a signal propagation delay from one of the plurality of noncollated antennae to another one of the plurality of non-collated antennae via the at least one RFID tag.

5. The RFID reader of claim 2, further comprising a processor coupled with the timing circuit to determine a length of the signal path of the at least one RFID tag by calculating a signal propagation delay from one of the plurality of noncollated antennae to another one of the plurality of non-collated antennae via the at least one RFID tag.

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

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

a plurality of antennae;

a radio frequency (RF) source for signal transmission;

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

a phase comparison circuit coupled with the receiver, wherein the phase comparison circuit is configured to compare relative phases of backscatter received from at least two of the plurality of antennae.

8. The RFID reader of claim 7, wherein the plurality of antennae are non-collated antennae.

9. The RFID reader of claim 8, further comprising a processor coupled with the phase comparison circuit to determine location information of the at least one RFID tag from the comparison of relative phases of backscatter received from at least two of the plurality of antennae.

10. The RFID reader of claim 8, further comprising a processor coupled with the phase comparison circuit to determine distance information of the at least one RFID tag from the comparison of relative phases of backscatter received from at least two of the plurality of antennae.

11. The RFID reader of claim 8, further comprising a processor coupled with the phase comparison circuit to determine a length of the signal path of the at least one RFID tag from the comparison of relative phases of backscatter received from at least two of the plurality of antennae.

12. The RFID reader of claim 7, further comprising a low noise amplifier coupled with the receiver and one of the plurality of antennae for signal reception.