METHODS AND APPARATUS FOR RFID TAG PLACEMENT

• US 20080018327A1
• Filed: 07/24/2006
• Published: 01/24/2008
• Est. Priority Date: 07/24/2006
• Status: Active Grant

• Current Assignee: Novanta Corporation (Novanta Inc.)
• Original Assignee: ThingMagic, Inc. (Novanta Inc.)
• Inventors: Reynolds, Matthew S.
• Granted Patent: US 7,683,780 B2
• Time in Patent Office: Days
• US Class Current: 324/200
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G01R 33/10 Plotting field distribution ; Measuring field distribution
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

Systems and methods for placing RFID tags on objects are shown and described. The method includes scanning an object and analyzing one or more reflected signals from the to determine a suggested location for placement of an RFID tag. The scan can be accomplished using a scanning device having an antenna that operates in the near field of the object to measure at least one RF property of the reflected signal from the object.

Claims

1. A method of determining a location to place an RFID tag on a object, the method comprising:

scanning an object, with a scanning device having an antenna in the near field of the object, to measure at least one RF property of the reflected signal from the object; and

analyzing the reflected signal to determine a suggested location for placement of an RFID tag.

2. The method of claim 1 wherein the scanning comprises scanning the object in the near field of the object to measure the permeability of the object at one or more locations on a surface of the object.

3. The method of claim 1 wherein the scanning comprises scanning the object in the near field of the object to measure the permittivity of the object at one or more locations on a surface of the object.

4. The method of claim 1 wherein the scanning comprises scanning the object in the near field of the object to measure the loss tangent of the object at one or more locations on a surface of the object.

5. The method of claim 1 wherein the scanning comprises electrically scanning the object with an antenna.

12. The method of claim 1 wherein the scanning comprises mechanically scanning the object.

13. The method of claim 1 wherein the analyzing comprises estimating the far-field radiation pattern of an antenna on the object based on the measured at least one property.

14. The method of claim 1 wherein the analyzing comprises analyzing the magnitude of the reflected signal.

15. The method of claim 1 wherein the analyzing comprises analyzing the phase of the reflected signal.

16. The method of claim 1 wherein the analyzing comprises analyzing the reflected signal for nonlinear behavior.

17. The method of claim 1 further comprising calibrating the scanning device prior to scanning the object.

18. The method of claim 17 wherein the calibrating comprises reading calibration data stored with an antenna element that is part of the scanning device.

19. The method of claim 17 wherein the calibrating comprises executing a free-space calibration routine.

20. The method of claim 18 wherein the analyzing comprising generating a ratio of the reflected signal to the calibration signal.

21. The method of claim 18 wherein the analyzing comprises generating a figure of merit of location quality.

22. The method of claim 1 further comprising indicating a result of the analysis to the end-user of the scanning device.

23. The method of claim 22 wherein the indicating comprises displaying a suggested location for placing the RFID tag.

24. The method of claim 21 wherein the indicating comprises providing an audio alert to the end-user of the scanning device.

25. The method of claim 21 wherein the indicating comprises marking the object in the location suggested for tag placement.

7. The method of claim 7 wherein the scanning comprises scanning the object in the near field of the object to measure the complex return loss of the antenna when influenced by the object.

6. The method of claim 7 wherein the scanning comprises scanning the object in the near field of the object to measure the impedance of the antenna when influenced by the object at one or more locations on a surface of the object.

8. The method of claim 7 wherein the antenna is an array of antenna elements.

9. The method of claim 8 wherein at least one antenna of the array is selected from the group consisting of a dipole antenna, a resonant coil antenna, an non-resonant coil antenna, a microstrip antenna, a patch antenna, a slot antenna, a spiral antenna, and a logarithmic antenna.

10. The method of claim 7 wherein the scanning comprises electrically scanning the object with an interchangeable antenna.

11. The method of claim 7 wherein the antenna is selected to substantially mimic an RFID tag antenna.

26. An apparatus for scanning an object in the near field, the apparatus comprising:

a housing that encloses an RF source, a transmitter in communication with the RF source, an antenna in communication with the transmitter, and a receiver; and

a controller in communication with at least the RF source and the receiver, the controller generating a scan signal that results in irradiation of an object, receiving a reflection signal of the irradiated object, and analyzing at least one property of the reflection signal to determine a suggested location for placement of an RFID tag.

27. The apparatus of claim 26 wherein the antenna is interchangeable.

28. The apparatus of claim 26 wherein the antenna comprises an array of antenna elements.

29. The apparatus of claim 26 wherein the antenna is selected from the group consisting of a dipole antenna, a resonant coil antenna, a non-resonant coil antenna, a microstrip antenna, a patch antenna, a slot antenna, a spiral antenna, and a logarithmic antenna.

30. The apparatus of claim 26 wherein the controller analyzes the reflected signal to measure the permeability of the object at one or more locations on a surface of the object.

31. The apparatus of claim 26 wherein the controller analyzes the reflected signal to measure the permittivity of the object at one or more locations on a surface of the object.

32. The apparatus of claim 26 wherein the controller analyzes the reflected signal to measure the loss tangent of the object at one or more locations on a surface of the object.

33. The apparatus of claim 26 wherein the controller analyzes the reflected signal to measure the impedance of the antenna when influenced by the object.

34. The apparatus of claim 26 wherein the controller analyzes the reflected signal to measure the complex return loss of the antenna when influenced by the object.

35. The apparatus of claim 26 wherein the controller analyzes the reflected signal by at least estimating the far-field electromagnetic properties of the RFID tag.

36. The apparatus of claim 26 wherein the controller analyzes the reflected signal for nonlinear behavior.

37. The apparatus of claim 26 wherein the controller analyzes the magnitude of the reflected signal.

38. The apparatus of claim 26 wherein the controller analyzes the phase of the reflected signal.

39. The apparatus of claim 26 further comprising a display in communication with the controller, the display indicating a suggested location for placing the RFID tag.

40. The apparatus of claim 26 further comprising an audio transducer in communication with the controller, the audio transducer providing an audio alert to the end-user of the scanning device.

41. The apparatus of claim 26 further comprising a marking apparatus in communication with the controller, the marking apparatus marking the object in the location suggested for tag placement.

42. The apparatus of claim 26 wherein the end-user causes the execution of a calibration routine to calibrate the scanning device prior to scanning the object.

43. The apparatus of claim 42 wherein the calibration routine comprises a free-space calibration routine.

44. The apparatus of claim 42 wherein the controller analyzes the reflected signal and the calibration signal to generate a ratio of the reflected signal to the calibration signal.

45. The apparatus of claim 26 wherein the controller reads calibration data stored with the antenna.

46. The apparatus of claim 26 wherein the housing comprises a hand-held form factor.