Dynamically reconfigurable antennas for RFID label encoders/readers

• US 7,724,141 B2
• Filed: 11/03/2005
• Issued: 05/25/2010
• Est. Priority Date: 08/19/2005
• Status: Active Grant

• Current Assignee: Novanta Corporation (Novanta Inc.)
• Original Assignee: ThingMagic, Inc. (Novanta Inc.)
• Inventors: Reynolds, Matthew Stephen
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US11/265,477
• Publication Number:
  US 20070040689A1
• Time in Patent Office: 1,664 Days
• Field of Search: 340/572.1, 340/572.7, 343/853, 343/876
• US Class Current: 340/572.7
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• 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: H04B 7/0602 using antenna switching H04B7/0686 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/0802 using antenna selection H04B7/0868 takes precedence; antenna beam directivity switching H01Q3/24
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity

Abstract

A dynamically reconfigurable antenna system for an RFID (Radio Frequency Identification) reader/encoder includes a plurality of antenna elements; and a mechanism constructed and adapted to dynamically and selectively configure said plurality of antenna elements during operation thereof. The antenna elements may be arranged in a pattern of conductive areas, and each antenna element is switchably connectable to ground or to a transmission line connectable to the RFID reader/encoder. Each antenna element may be square, rectangle, circular, or diamond shaped. The antenna elements may located on an inner layer of the multi-layer printed circuit and wherein regions above the antenna elements are a dielectric layer or a slot aperture. The antenna system may be incorporated into an RFID encoder/reader.

Claims

1. A dynamically reconfigurable antenna system for an RFID (Radio Frequency Identification) reader/encoder, the antenna system comprising:

a plurality of antenna elements; and

a configuring mechanism constructed and adapted to dynamically and selectively configure said plurality of antenna elements, wherein more than one antenna element is simultaneously connected to the RFID reader/encoder, and

wherein the plurality of antenna elements are arranged in a pattern of conductive areas , and wherein each antenna element is selectively and dynamically connectable via a switch to ground or to a transmission line connectable to the RFID reader/encoder.

2. An antenna system as in claim 1 wherein each antenna element is selectively and dynamically switchable to one of:

ground, a terminating impedance, or one of two transmission lines carrying excitation signals of differing phases.

3. An antenna system as in claim 1 wherein the pattern is a regular repeating pattern.

4. An antenna system as in claim 3 wherein the antenna elements are arranged in a grid.

5. An antenna system as in claim 3 wherein the antenna elements are arranged as a grid of square-shaped elements.

6. An antenna system as in claim 1 wherein each antenna element has a shape selected from the group comprising:

squares, rectangles, circles, and diamond shape.

7. An antenna system as in claim 1 comprising sixteen square antenna elements arranged in a grid.

8. An antenna system as in claim 1 comprising:

four separate rectangular antenna elements arranged in a cross shape on a rectangular region of a layer of an antenna substrate; and

four switches, each connectable to the RFID encoder/reader, and each operable to switch a corresponding one of the antenna elements between ground and the RFID encoder/reader.

9. An antenna system as in claim 1 wherein the antenna elements are formed as isolated conductive areas on a layer of a substrate.

10. An antenna system as in claim 9 wherein the layer is a top layer of the substrate.

11. An antenna system as in claim 9 wherein the antenna elements are located on an inner layer of the multi-layer printed circuit and wherein regions above the antenna elements comprise a dielectric layer or a slot aperture.

12. An antenna system as in claim 1 wherein the antenna elements are formed as isolated conductive areas on a layer of a multi-layer printed circuit (PC).

13. A dynamically reconfigurable antenna system for an RFID Radio Frequency Identification reader/encoder, the antenna system comprising:

a plurality of antenna elements; and

a configuring mechanism constructed and adapted to dynamically and selectively configure said plurality of antenna elements, wherein more than one antenna element is simultaneously connected to the RFID reader/encoder, and wherein the configuring mechanism comprises;

a plurality of switches for selectively switching at least some of said antenna elements to a transmission line or to ground.

14. An antenna system as in claim 13 each of said switches is selectively switchable to one of:

ground, a terminating impedance, and one of two transmission lines carrying signals of differing phases.

15. An antenna system as in claim 13 wherein there are N antenna elements and N switches.

16. An antenna system as in claim 15 wherein N is 2, 3 or 4.

17. An antenna system as in claim 13 wherein the antenna elements are formed as isolated conductive areas on a layer of a substrate.

18. An antenna system as in claim 17 wherein the layer is a top layer of the substrate.

19. An antenna system as in claim 17 wherein the antenna elements are located on an inner layer of the multi-layer printed circuit and wherein regions above the antenna elements comprise a dielectric layer or a slot aperture.

20. An antenna system as in claim 13 wherein the antenna elements are formed as isolated conductive areas on a layer of a multi-layer printed circuit (PC).

21. An antenna system as in claim 13 comprising sixteen square antenna elements arranged in a grid.

22. A method of operating an RFID reader/encoder, the method comprising:

(A) providing a dynamically reconfigurable antenna system comprising;

(a1) a plurality of antenna elements; and

(a2) a configuring mechanism constructed and adapted to dynamically and selectively configure said plurality of antenna elements; and

(B) dynamically configuring the antenna system by selectively configuring at least some of the antenna elements prior to or during operation of the RFID reader/encoder,

wherein more than one antenna element is simultaneously connected to the RFID reader/encoder, and

wherein the plurality of antenna elements are arranged in a regular repeating pattern of conductive areas, and wherein each antenna element is connectable via a switch to ground or to a transmission line connectable to the RFID reader/encoder.

23. A method as in claim 22 wherein the antenna elements are arranged in an N×

N grid of square-shaped elements formed as isolated conductive areas on a layer of a substrate.

24. A method as in claim 23 where the value of N is 2, 3 or 4.

25. A method of operating an RFID reader/encoder, the method comprising:

(A) providing a dynamically reconfigurable antenna system comprising;

(a1) a plurality of antenna elements; and

(a2) a configuring mechanism constructed and adapted to dynamically and selectively configure said plurality of antenna elements and

(B) dynamically configuring the antenna system by selectively configuring at least some of the antenna elements prior to or during operation of the RFID reader/encoder,

wherein more than one antenna element is simultaneously connected to the RFID reader/encoder, and

wherein there are four rectangular antenna elements arranged in a cross shape on a region of a layer of an antenna substrate, and wherein the configuring mechanism comprises four switches configured to switch corresponding ones of said antenna elements between ground and a transmission line connectable to the RFID reader/encoder.

26. A method as in claim 25 wherein the antenna elements are arranged in an N×

N grid of square-shaped elements formed as isolated conductive areas on a layer of a substrate.

27. A method as in claim 26 where the value of N is 2, 3 or 4.