METHOD AND APPARATUS FOR IMPROVING THE EFFICIENCY AND ACCURACY OF RFID SYSTEMS

• US 20090066481A1
• Filed: 11/13/2008
• Published: 03/12/2009
• Est. Priority Date: 03/05/2004
• Status: Abandoned Application

• Current Assignee: Seknion Incorporated
• Original Assignee: Seknion Incorporated
• Inventors: Hansen, Thorkild, Oristaglio, Michael L.
• Application Number:
  US12/270,045
• Publication Number:
  US 20090066481A1
• Time in Patent Office: Days
• US Class Current: 340/10.200
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: H04K 2203/20 for contactless carriers, e.g. RFID carriers record carriers with integrated circuit chips including means for preventing undesired reading or writing from or to record carriers by hindering electromagnetic reading or writing G06K19/07318; arrangements for sensing record carriers including arrangements for protecting the interrogation against piracy attacks G06K7/10257
• CPC Class Codes: H04K 2203/32 including a particular configuration of antennas
• CPC Class Codes: H04K 3/43 characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area
• CPC Class Codes: H04K 3/825 by jamming

Abstract

The present invention relates to a method and apparatus for transmitting a narrow signal beam that allows the precise location of RFID tags to be determined and reduces tag collisions. The present invention further relates to a method and apparatus for combing an RFID reader with an optical source to visualize the interrogation zone of the reader. The present invention also relates to a method and apparatus for improving the efficiency of RFID systems.

Claims

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27. A method for improving the efficiency of RFID systems having RFID readers and RFID tags, comprising the steps of:

employing an antenna array by an RFID reader,

broadcasting a data signal using said antenna array,

broadcasting a scramble signal using said antenna array, and

adjusting array excitation coefficients of said antenna array for said data signal and said scramble signal such that said scramble signal overshadows said data signal in all but selected regions.

28. The method of claim 27, wherein said antenna array employs patch antennas.

29. The method of claim 27, further comprising the step of employing three antenna elements by said RFID reader, wherein two antenna elements transmit said scramble signal and one antenna element interrogates RFID tags.

30. The method of claim 27, further comprising the step of adjusting the array excitation coefficients for said data signal and said scramble signal to create an interrogation beam that fits an opening in a container.

31. The method of claim 27, further comprising the step of employing an antenna, wherein said antenna transmits two or more interrogation beams and wherein any of said RFID tags in said interrogation zone receive sufficient power to operate from at least one of said two or more interrogation beams.

32. The method of claim 27, further comprising the step of employing two or more scramble signals, wherein said two or more scramble signals prevent leakage of said data signal.

33. The method of claim 32, wherein two or more scramble signals employ coefficients that are mirror images.

34. The method of claim 27, further comprising the step of transmitting said data signal and said scramble signal adjusted to create closely spaced disjoint interrogation zones.

35. The method of claim 27, wherein the position of said RFID reader is determined from the solution of an inverse source problem.

36. The method of claim 35, wherein the inverse source problem is solved with an iterative optimization scheme.

37. The method of claim 27, wherein the position of said RFID reader is determined from measurements.

38. The method of claim 27, wherein the array excitation coefficients are determined from the solution to an inverse source problem.

39. The method of claim 38, wherein the inverse source problem is solved with an iterative optimization scheme.

40. The method of claim 27, wherein the array excitation coefficients are determined from measurements.

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