Antenna system for radio frequency identification

• US 6,985,122 B2
• Filed: 10/22/2004
• Issued: 01/10/2006
• Est. Priority Date: 10/22/2003
• Status: Active Grant

• Current Assignee: Fractal Antenna Systems Inc.
• Original Assignee: Nathan Cohen
• Inventors: Cohen, Nathan
• Primary Examiner(s): Lee, Wilson
• Assistant Examiner(s): AL NAZER, LEITH A
• Application Number:
  US10/971,815
• Publication Number:
  US 20050151697A1
• Time in Patent Office: 445 Days
• Field of Search: 343/700.MS, 343/702, 343/767, 343/770, 343/793, 343/795, 343/796, 343/895, 343/794, 343/802, 343/807, 343/808, 343/818, 343/819
• 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:

an electrically conductive portion defined substantially by a self-similar geometry present at multiple resolutions, wherein the electrically conductive portion includes two or more angular bends and is configured to radiate broadband electromagnetic energy, wherein the electrically conductive portion includes an element defined substantially by a V-shaped geometry, wherein the angular bends of the electrically conductive portion include vertices, each having an acute included angle; and

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

2. The antenna of claim 1, wherein the electrically conductive portion includes an element defined substantially by a rectangular geometry.

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

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

1 ratio frequency band.

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

1 ratio frequency band.

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

7. The antenna of claim 1, wherein the electrically conductive portion includes a ground plane.

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

9. A radio frequency identification system comprising:

an antenna including,

an electrically conductive portion defined substantially by a self-similar geometry present at multiple resolutions, wherein the electrically conductive portion includes two or more angular bends and is configured to radiate broadband electromagnetic energy, wherein the electrically conductive portion includes an element defined substantially by a V-shaped geometry, wherein the angular bends of the electrically conductive portion include vertices, each having an acute included angle, 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.

10. The radio frequency identification system of claim 9, wherein the broadband electromagnetic energy radiates within a 10:

1 ratio frequency band.

11. The radio frequency identification system of claim 9, wherein the broadband electromagnetic energy radiates within a 50:

1 ratio frequency band.

12. The radio frequency identification system of claim 9, wherein the antenna includes a dipole geometry.

13. The radio frequency identification system of claim 9, wherein the antenna includes a monopole geometry.

14. The radio frequency identification system of claim 9, wherein the antenna is surface mounted.

15. The radio frequency identification system of claim 9, wherein the electrically non-conductive portion includes a dielectric material.

16. The radio frequency identification system of claim 9, wherein the antenna is configured to provide a substantially constant output impedance across a broad frequency band.

17. The radio frequency identification system of claim 9 wherein the integrated circuit is configured to initiate transmitting of an electromagnetic signal at the antenna.