Adjustable length antenna system for RF transponders

• US 6,535,175 B2
• Filed: 01/19/2001
• Issued: 03/18/2003
• Est. Priority Date: 06/01/2000
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Friedman, Daniel J., Duan, Dah-Weih, Murphy, Philip, Brady, Michael John, Cofino, Thomas Anthony, Kodukula, Venkata S. R., Scott, Dale Larry, Pinch, Michael Louis, Madrid, Michael Brent, Heinrich, Harley Kent, Moskowitz, Paul Andrew
• Primary Examiner(s): Ho, Tan
• Application Number:
  US09/765,800
• Publication Number:
  US 20020003496A1
• Time in Patent Office: 788 Days
• Field of Search: 343/703, 343/815, 343/817, 343/818, 343/745, 343/749, 343/795, 340/572.1, 340/572.7
• US Class Current: 343/795
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• 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 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• 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 9/14 Length of element or elements adjustable telescopic elements H01Q1/10
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00
• CPC Class Codes: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407

Abstract

The present invention provides an RF tag having an antenna that can be selectively tuned to achieve optimal performance. The RF tag comprises an RF transponder integrated circuit and an antenna connected to the RF transponder integrated circuit. The antenna includes components such as tuning stubs and loading bars that are physically alterable to selectively vary the performance characteristics of the antenna. The tuning stub and loading bar may each further comprising a variably selectable length having elements that may be removed by punching, cutting, etching, laser trimming or other process. The antenna may further comprise a leadframe or a flexible substrate.

Claims

1. An RF transponder, comprising:

an RF transponder integrated circuit; and

an antenna connected to said RF transponder integrated circuit, said antenna having components that are physically alterable to change dimensions of said antenna to selectively vary performance characteristics of said antenna.

2. The RF transponder of claim 1, wherein said components comprise tuning stubs having removable elements.

3. The RF transponder of claim 1, wherein said antenna components comprise loading bars having removable elements.

4. The RF transponder of claim 1, wherein said antenna further comprises a leadframe.

5. The RF transponder of claim 1, wherein said antenna further comprises a flexible substrate.

6. An RF transponder, comprising:

an RF transponder integrated circuit; and

a dipole antenna connected to said RF transponder integrated circuit, said antenna having a tuning stub coupled to a dipole element of said dipole antenna and a loading bar spaced from said dipole antenna, said tuning stub and said loading bar each further comprising a variably selectable length;

wherein, an impedance characteristic of said dipole antenna is defined in part of said variably selectable lengths of said tuning stub and said loading bar.

7. The RF transponder of claim 6, wherein said tuning stub further comprises plural removable elements defining respective lengths of said tuning stub.

8. The RF transponder of claim 7, wherein said tuning stub is further adaptable to provide one of an open-circuit and a closed-circuit configuration.

9. The RF transponder of claim 6, wherein said loading bar further comprises plural removable elements defining respective lengths of said loading bar.

10. The RF transponder of claim 6, wherein said dipole antenna further comprises a leadframe.

11. The RF transponder of claim 6, wherein said dipole antenna further comprises a flexible substrate.

12. A method of tuning an antenna for an RF transponder, comprising:

sending a test signal to an antenna of an initial size and dimension;

measuring the strength of a radiated signal received from the antenna;

adjusting at least one physical characteristic of the antenna; and

repeating said measuring and adjusting steps until optimum strength of the radiated signal is obtained.

13. A method of tuning an antenna for an RF transponder, comprising:

sending a test signal to an antenna of an initial size and dimension;

measuring the strength of a radiated signal received from the antenna;

adjusting at least one physical characteristic of the antenna; and

repeating said measuring and adjusting steps until optimum strength of the radiated signal is obtained;

wherein said antenna further comprises components that are physically alterable to selectively vary performance characteristics of said antenna, and said adjusting step further comprises adjusting dimensions of said physically alterable components.

14. A method of tuning an antenna for an RF transponder, comprising:

sending a test signal to an antenna of an initial size and dimension;

measuring the strength of a radiated signal received from the antenna;

adjusting at least one physical characteristic of the antenna; and

repeating said measuring and adjusting steps until optimum strength of the radiated signal is obtained;

wherein said adjusting step further comprises removing a portion of a tuning stub of said antenna in order to alter impedance of said antenna.

15. A method of tuning an antenna for an RF transponder, comprising:

sending a test signal to an antenna of an initial size and dimension;

measuring the strength of a radiated signal received from the antenna;

adjusting at least one physical characteristic of the antenna; and

repeating said measuring and adjusting steps until optimum strength of the radiated signal is obtained;

wherein said adjusting step further comprises removing a portion of a loading bar of said antenna in order to alter impedance of said antenna.

16. An apparatus for tuning RF transponders, comprising:

a transport mechanism including a supply reel and a take-up reel adapted to transport a tape along a transport path extending therebetween, said tape having a plurality of RF transponder antennas formed thereon, said antennas further comprising respective components that are physically alterable to selectively vary an impedance characteristic of said antennas; and

a punching tool disposed on said path between said supply reel and said take-up reel, said punching tool being selectively movable laterally with respect to said tape to execute a punching operation in a portion of said tape corresponding with one of said physically alterable components;

wherein each of said RF transponder antennas of said tape can be adapted to have unique impedance characteristics.

17. The apparatus of claim 16, further comprising means for measuring impedance of said antennas.

18. The apparatus of claim 16, further comprising means for determining the placement of said punching tool with respect to said tape.

19. The apparatus of claim 16, further comprising means for controlling the movement of said punching tool to execute said punching operation.