Broken-loop RFID reader antenna for near field and far field UHF RFID tags

Description

An article in which the design is embodied is an antenna for a Radio Frequency Identification (RFID) reader system, as it would be used for reading Ultra High Frequency (UHF) RFID tags.

The design includes one or more conductive loops, at least one of which is broken into segments. The segments can be electrically driven at feedpoints by an electrical signal alternating at the proper frequency, which can be around 900 MHz.

In the far field, an electromagnetic pattern is formed that is equivalent to, and sometimes indistinguishable from, that of a dipole. This way RFID tags can be read as known.

In the near field, each segment generates an individual magnetic field. Plus, the segments are so arranged that the individual magnetic fields are cumulated, to form an aggregate magnetic field that can be used for reading the UHF RFID tags. The magnetic field can read RFID tags better than an electromagnetic field, in some instances that involve fluids or metals with which the RFID tags can be associated.

Advantageously, the segments of the broken loop(s) are further arranged so that not all of them need be electrically driven. Only some need be driven; and the driving field couples also into the others. By proper geometry, dimensioning, and the like, the phase difference of each field propagating within a segment can be substantially matched to that of coupling to another segment, so that the generated individual magnetic fields are cumulated.

The FIGURE is a top plan view of a broken-loop RFID reader antenna for near field and far field UHF RFID tags showing my new design. It is understood that the broken line segments in the drawing form no part of the claimed design.

Claims

CLAIM The ornamental design for a broken-loop RFID reader antenna for near field and far field UHF RFID tags, as shown.

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Inventors:	Oliver; Ronald A. (Seattle, WA)
Assignee:	Impinj, Inc. (Seattle, WA)
Appl. No.:	D/303,663
Filed:	February 14, 2008

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Current U.S. Class:	D14/230; D14/233
Current International Class:	1403
Field of Search:	;D14/138,230-238,299,358 ;D12/42,43 ;343/700MS,700R-705,711-713,741,748,767,795,819,840,846,866,871-908 ;455/90.2,90.3,91,128,269,344,347,562.1

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References Cited [Referenced By]

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U.S. Patent Documents

2617033	November 1952	Posthumus
5973644	October 1999	Haneishi et al.
6445354	September 2002	Kunysz
6961023	November 2005	Fujii et al.
7079080	July 2006	Mizuno et al.
7106201	September 2006	Tuttle
7205947	April 2007	Parsche
D546820	July 2007	Oliver
D547306	July 2007	Oliver
D548225	August 2007	Oliver
2002/0067315	June 2002	Kunysz
2004/0125023	July 2004	Fujii et al.
2005/0259030	November 2005	Mizuno et al.

Primary Examiner: Zarfas; Louis S
Assistant Examiner: Windmuller; John
Attorney, Agent or Firm: Adorno & Yoss, LLC Turk; Carl K. Kavounas; Gregory T.