Antenna system for radio frequency identification

• US 7,345,642 B2
• Filed: 01/09/2006
• Issued: 03/18/2008
• Est. Priority Date: 10/22/2003
• Status: Expired due to Fees

• Current Assignee: Fractal Antenna Systems Inc.
• Original Assignee: Fractal Antenna Systems Inc.
• Inventors: Cohen, Nathan
• Primary Examiner(s): Dinh; Trinh Vo
• Application Number:
  US11/327,982
• Publication Number:
  US 20060119520A1
• Time in Patent Office: 799 Days
• Field of Search: 343/793, 343/795, 343/700.MS, 343/895, 343/767, 343/770
• US Class Current: 343/793
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 15/0093 having a fractal shape
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/26 with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

An antenna including an electrically conductive portion defined substantially by a self-similar geometry present at multiple resolutions. The electrically conductive portion includes two or more angular bends and is configured to radiate broadband electromagnetic energy. The antenna further includes an electrically non-conductive portion that structurally supports the electrically conductive portion.

Claims

1. An antenna comprising:

first and second electrically conductive portions defined substantially by a self-similar geometry present at multiple resolutions, each electrically conductive portions include first and second portions, wherein the first and second portions of each electrically conductive portion are substantially mirror images of the first and second portions of the other electrically conductive portion, wherein each of the first and second portions consists of a trace and has two and more angular bends, and each bend has a distal end and a proximal end, wherein in each electrically conductive portion, the proximal ends are connected to the trace, and the distal ends of the first electrically conductive portion abut the distal ends of second electrically conductive portion along a line dividing the first and second electrically conductive portions, and wherein the distal ends of the first and second electrically conductive portions are offset from one another along the line by a distance substantially equal to the thickness of the corresponding angular bend, forming a closed pattern, wherein the electrically conductive portions are configured to radiate broadband electromagnetic energy; and

an electrically non-conductive portion that structurally supports the electrically conductive portion.

2. The antenna of claim 1, wherein the electrically conductive portions include an element defined substantially by a V-shaped geometry.

3. The antenna of claim 1, wherein the electrically conductive portions include an element defined substantially by a rectangular geometry.

4. The antenna of claim 1, wherein the geometry of self-similarity at multiple resolutions includes a deterministic fractal.

5. The antenna of claim 1, wherein the broadband electromagnetic energy radiates substantially within a 10:

1 ratio frequency band.

6. The antenna of claim 1, wherein the broadband electromagnetic energy radiates substantially within a 50:

1 ratio frequency band.

7. The antenna of claim 1, wherein the broadband electromagnetic energy radiates between 400 MHz and 6000 MHz.

8. The antenna of claim 1, wherein the electrically conductive portions include a ground plane.

9. The antenna of claim 1, wherein the conductive material is metallic.

10. A radio frequency identification system comprising:

an antenna including,

first and second electrically conductive portions defined substantially by a self-similar geometry present at multiple resolutions, each electrically conductive portions include first and second portions, wherein the first and second portions of each electrically conductive portion are substantially mirror images of the first and second portions of the other electrically conductive portion, wherein each of the first and second portions consists of a trace and has two and more angular bends, and each bend has a distal end and a proximal end;

wherein in each electrically conductive portion, the proximal ends are connected to the trace, and the distal ends of the first electrically conductive portion abut the distal ends of second electrically conductive portion along a line dividing the first and second electrically conductive portions, and wherein the distal ends of the first and second electrically conductive portions are offset from one another along the line by a distance substantially equal to the thickness of the corresponding angular bend, forming a closed pattern, wherein the electrically conductive portions are configured to radiate broadband electromagnetic energy, and an electrically non-conductive portion that structurally supports the electrically conductive portion; and

an integrated circuit in communication with the antenna, wherein the integrated circuit is configured to respond to an electromagnetic signal received by the antenna.

11. The radio frequency identification system of claim 10, wherein the broadband electromagnetic energy radiates within a 10:

1 ratio frequency band.

12. The radio frequency identification system of claim 10, wherein the broadband electromagnetic energy radiates within a 50:

1 ratio frequency band.

13. The radio frequency identification system of claim 10, wherein the antenna includes a dipole geometry.

14. The radio frequency identification system of claim 10, wherein the antenna includes a monopole geometry.

15. The radio frequency identification system of claim 10, wherein the antenna is surface mounted.

16. The radio frequency identification system of claim 10, wherein the electrically non-conductive portions include a dielectric material.

17. The radio frequency identification system of claim 10, wherein the antenna is configured to provide a substantially constant output impedance across a broad frequency band.

18. The radio frequency identification system of claim 10 wherein the integrated circuit is configured to initiate transmitting of an electromagnetic signal at the antenna.