RF Tag having high dielectric constant material

• US 6,329,915 B1
• Filed: 04/24/1999
• Issued: 12/11/2001
• Est. Priority Date: 12/31/1997
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Inventors: Brady, Michael J., Field, Christopher A., Duncombe, Peter R., Afzali-ardakani, Ali, Moskowitz, Paul A., Duan, Dah-Weih
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): PHAM, TOAN NGOC
• Application Number:
  US09/296,193
• Time in Patent Office: 962 Days
• Field of Search: 340/572.1, 340/572.2, 340/572.4, 340/572.7, 340/572.8, 340/825.54, 343/785, 343/864, 343/873, 343/911.R, 343/700.MS
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• 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: G08B 13/2414 using inductive tags
• CPC Class Codes: G08B 13/2417 having a radio frequency identification chip
• CPC Class Codes: G08B 13/2431 Tag circuit details
• CPC Class Codes: G08B 13/2437 Tag layered structure, processes for making layered tags
• CPC Class Codes: G08B 13/2442 Tag materials and material properties thereof, e.g. magnetic material details
• CPC Class Codes: G08B 13/2462 Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00
• 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 13/02 Waveguide horns
• CPC Class Codes: H01Q 15/16 curved in two dimensions, e.g. paraboloidal
• CPC Class Codes: H01Q 19/106 using two or more intersecting plane surfaces, e.g. corner reflector antennas
• CPC Class Codes: H01Q 19/132 Horn reflector antennas; Off-set feeding
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 9/0414 in a stacked or folded configuration
• CPC Class Codes: H01Q 9/0428 radiating a circular polarised wave

Abstract

A radio frequency (RF) transponder (RF tag) is proposed, where a high dielectric constant material is used in operative cooperation with a tag antenna so that the distance of the tag antenna from conducting or absorbing surfaces may be reduced, and so the tag dimensions may be reduced.

Claims

1. A radio frequency transponder (RF tag), comprising:

an antenna for communicating RF signals between the RF tag and a base station, the RF signals having a wavelength in free space;

an apparatus connected to the antenna, the apparatus for modulating the backscattering from the antenna; and

a high dielectric constant material operatively cooperating with the antenna to reduce the RF tag dimensions for optimally communicating RF signals between the RF tag and the base station.

2. A radio frequency transponder (RF tag), comprising:

an antenna for communicating RF signals between the RF tag and a base station, the RF signals having a wavelength in free space;

at least one semiconductor device connected to the antenna, the semiconductor device having a rectification power stage for rectifying signals from the antenna and powering the semiconductor device, a non-volatile memory, and logic circuits for receiving and sending signals from and to the antenna and for reading and writing from and to the non-volatile memory; and

a high dielectric constant material operatively cooperating with the antenna to reduce the RF tag dimensions for optimally communicating RF signals between the RF tag and the base station.

3. The RF tag of claim 2, wherein the high dielectric constant material has a thickness of less than one-quarter of the wavelength of the RF signal in free space.

4. The RF tag of claim 3, wherein the high dielectric constant material has a thickness of less than one-eighth of the wavelength of the RF signal in free space.

5. The RF tag of claim 2, wherein the high dielectric constant material has a thickness of less than one-quarter of the wavelength of the RF signal in free space and is interposed between the antenna and an external electrically conducting surface.

6. The RF tag of claim 2, further comprising an electrically conducting material, wherein the high dielectric constant material has a thickness of less than one-quarter of the wavelength of the RF signal in free space and wherein the high dielectric constant material is interposed between the antenna and the electrically conducting material.

7. The RF tag of claim 2, wherein the maximum dimension of the antenna is less than the maximum dimension of the semiconductor device.

8. The RF tag of claim 7, wherein the antenna is connected to the semiconductor device before the semiconductor device is separated from a wafer used in the production of the semiconductor device.

9. The RF tag of claim 7, wherein the high dielectric constant material is applied to the semiconductor device before the semiconductor device is separated from a wafer used in the production of the semiconductor device.

10. The RF tag of claim 2, wherein the high dielectric constant material has dielectric constant greater than 20.

11. The RF tag of claim 10, wherein the high dielectric constant material has dielectric constant greater than 50.

12. The RF tag of claim 11, wherein the high dielectric constant material has dielectric constant greater than 100.

13. A semiconductor wafer, comprising:

at first large plurality of discrete semiconductor devices, each discrete semiconductor device having a rectification power stage for rectifying signals from an antenna and powering the semiconductor device, a non-volatile memory, and logic circuits for receiving and sending signals from and to the antenna and for reading and writing from and to the non-volatile memory;

a second large plurality of antennas, each of the antennas connected to one of the discrete semiconductor devices, and

a high dielectric constant material operatively cooperating with the antennas and semiconductor devices to form RF tags having dimensions for optimally communicating RF signals between the RF tag and a base station.

14. The semiconductor wafer of claim 13, wherein a high dielectric constant material is applied as a first layer to the semiconductor after the semiconductor devices have been fabricated, and wherein the antenna structures are fabricated on the first layer and connected to the semiconductor devices, and wherein a second layer of a high dielectric constant material is applied over the antenna structures.

15. The semiconductor wafer of claim 14, wherein the second layer has a thickness greater than one quarter the wavelength of the RF signals in the dielectric material of the second layer.

16. The semiconductor wafer of claim 15, wherein the second layer has a thickness greater than one half the wavelength of the RF signals in the dielectric material of the second layer.

17. The semiconductor wafer of claim 13, wherein the high dielectric constant material has a dielectric constant greater than 20.

18. The semiconductor wafer of claim 17, wherein the high dielectric constant material has a dielectric constant greater than 50.

19. The semiconductor wafer of claim 18, wherein the high dielectric constant material has a dielectric constant greater than 100.