Waveguide for transmitting RF energy through an RF barrier

• US 6,388,630 B1
• Filed: 07/21/2000
• Issued: 05/14/2002
• Est. Priority Date: 07/22/1999
• Status: Expired due to Fees

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: Supersensor Limited
• Inventors: Pieterse, Herman, Fourle, Andries Petrus Cronje, Turner, Christopher Gordon Gervase, Kruger, Johan Dawid
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Clinger, James
• Application Number:
  US09/624,006
• Time in Patent Office: 662 Days
• Field of Search: 343/767, 343/853, 343/850, 343/771, 340/572.1, 340/10.2, 340/572.7, 340/693.1, 340/27, 246/194, 342/44
• US Class Current: 343/767
• CPC Class Codes: G06K 17/0022 arrangements or provisious for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06K 19/07796 arrangements on the record carrier to allow stacking of a plurality of similar record carriers, e.g. to avoid interference between the non-contact communication of the plurality of record carriers
• 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 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: H01P 3/122 Dielectric loaded (not air)

Abstract

A spacer for items includes a waveguide 28.1 for radio frequency signals and a crate 16.1 or pallet. When items 16.1 to 16.9 in an array are spaced with such waveguides, signals from an interrogator 12 of an RF electronic identification system 10 are guided via the waveguide to transponders 14.1 to 14.9 of the system mounted on the items. Response signals from the transponders are similarly guided in the reverse direction, so that the transponders may be read. The spacer, arrangement and methods according to the invention alleviate the problems presented by an RF barrier in prior art systems.

Claims

1. A spacer for spacing separate goods relative to one another, the spacer comprising a body comprising a first wall and a second wall spaced therefrom collectively to form an inlet slot and a waveguide for guiding incident radio frequency waves traveling through free space, the waveguide having a characteristic impedance, the space further comprising an impedance matching arrangement for matching an impedance of free space with said characteristic impedance.

2. A spacer as claimed in claim 1 wherein the body comprises a carrier for the goods.

3. A spacer as claimed in claim 1 wherein the body comprises a container for the goods.

4. A spacer as claimed in claim 3, wherein the container is a crate.

5. A spacer as claimed in claim 1 wherein the body comprises a pallet.

6. A spacer as claimed in claim 1 wherein the slot defined between the first wall and the second wall is a slot antenna having an antenna impedance.

7. A spacer as claimed in claim 6 wherein the characteristic impedance of the waveguide matches the antenna impedance.

8. A spacer as claimed in claim 6 wherein the first wall comprises a first transversely extending lip formation, wherein the second wall comprises a second transversely extending lip formation and wherein the slot antenna is defined between the first lip formation and the second lip formation.

9. A spacer as claimed in claim 8 wherein part of the body of the spacer is removably receivable by one of the first and second lip formations.

10. A spacer as claimed in claim 1 wherein the impedance matching arrangement comprises a quarter wavelength transformer comprising a dielectric material.

11. A spacer as claimed in claim 1 comprising a transponder of a radio frequency electronic identification system.

12. An arrangement of separate items, each of at least some of the items comprising a transponder of a radio frequency identification system, the arrangement including at least one waveguide for radio frequency waves extending at least partially through the arrangement, to guide incident radio frequency waves propagating through free space from a reader of the system which is remote from the arrangement to at least partially through the arrangement.

13. An arrangement as claimed in claim 12 wherein the items are arranged in an array having parallel rows and columns and wherein the waveguide is provided between one of adjacent rows and adjacent columns.

14. A method of arranging a plurality of items each including a transponder of a radio frequency electronic identification system, the method including the steps of:

arranging the items in an arrangement; and

forming a waveguide for radio frequency waves between adjacent items in the arrangement extending through at least part of the arrangement, to guide radio frequency waves in between the adjacent items in the arrangement.

15. A method of identifying a plurality of items each comprising a transponder of a radio frequency electronic identification system also including a reader for the transponders, the method including the steps of:

arranging the items in an arrangement;

causing an incident radio frequency signal transmitted by the reader which is remote from the arrangement to be guided by a waveguide extending through at least part of the arrangement to at least some of the transponders in the arrangement; and

causing response signals from the at least some of the transponders to be guided towards the reader via the waveguide.

16. A spacer for spacing first and second goods, the spacer comprising a body comprising a first wall and a second wall spaced from the first wall and facing the first wall collectively to form between mutually facing inner surfaces of the first wall and the second wall, an inlet for radio frequency waves and a waveguide for the radio frequency waves for guiding the radio frequency waves in between first goods adjacent an outer surface of the first wall and second goods adjacent an outer surface of the second wall.

17. A spacer as claimed in claim 16 wherein the waveguide has a characteristic impedance and wherein the spacer further comprises an impedance matching arrangement for matching an impedance of free space with said characteristic impedance.