Radio frequency identification devices with separated antennas

• US 7,786,871 B2
• Filed: 05/23/2007
• Issued: 08/31/2010
• Est. Priority Date: 05/23/2007
• Status: Expired due to Fees

• Current Assignee: Radiant RFID, LLC (Embrace Software, Inc.)
• Original Assignee: Radiant RFID, LLC (Embrace Software, Inc.)
• Inventors: Schwarze, Stephan, Ratton, Kenneth L., Rubio-Ratton, Cynthia C.
• Primary Examiner(s): TWEEL JR, JOHN ALEXANDER
• Application Number:
  US11/752,810
• Publication Number:
  US 20080291026A1
• Time in Patent Office: 1,196 Days
• Field of Search: 340/572.7, 340/572.1, 340/572.4, 340/572.5, 340/572.8, 340/10.1
• US Class Current: 340/572.7
• 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 19/07786 the antenna being of the HF type, such as a dipole
• 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

Abstract

An RFID apparatus includes at least two antennas that are positioned to increase the maximum effective range of the RFID device. The RFID apparatus includes an RFID device, and the RFID device includes an antenna connected to a circuit having a transmitter. The second antenna is positioned relative to the RFID device to increase the MER of the RFID apparatus relative to conventional RFID devices while remaining separated (i.e. no direct physical contact) from the RFID device. In at least one embodiment, the second antenna is separated from the RFID device and positioned relative to the RFID device to induce a coupling of a signal to the RFID device. In at least one embodiment, the second antenna is positioned to overlay at least a portion of the circuit of the RFID device. In at least one embodiment, the RFID device is a passive-type RFID device.

Claims

1. An apparatus comprising:

a first radio frequency identification (RFID) device having a first antenna and a first circuit coupled to the first antenna; and

a second RFID device having a second antenna and a second circuit coupled to the second antenna, wherein the second antenna is separated from both the first RFID device and the first antenna and positioned with respect to the first RFID device to induce a current in the first RFID device that can be detected by the first circuit upon receipt of an input signal.

2. The apparatus of claim 1 further comprising:

multiple, additional RFID devices, wherein each additional RFID device includes a separate antenna coupled to a circuit, and each of the antennas of at least a subset of the additional RFID devices is positioned with respect to another one of the RFID devices to induce a current in the RFID device that can be detected by the circuit of the RFID device upon receipt of an input signal.

3. The apparatus of claim 1 wherein the RFID devices are configured into a wristband.

4. The apparatus of claim 1 wherein the first RFID device and the second antenna are disposed in separate planes.

5. The apparatus of claim 1 wherein the first antenna is positioned with the respect to the second RFID device to induce a current in the second RFID device that can be detected the second circuit upon receipt of the input signal.

6. The apparatus of claim 1 wherein the first circuit comprises a processor, a memory, and a transmitter and the second circuit comprises a processor, a memory, and a transmitter.

7. The apparatus of claim 1 wherein the second antenna is positioned to increase a maximum effective range of the first RFID device.

8. The apparatus of claim 1 wherein the second antenna includes a primary surface overlaying at least a portion of the first circuit.

9. The apparatus of claim 8 wherein the primary surface of the second antenna is separated from the first RFID device by a gap distance X, and 0.002 inches≦

X≦

0.008 inches.

10. The apparatus of claim 8 wherein the primary surface of the second antenna overlays between 0% to, and including, 100% of the first circuit of the first RFID device.

11. The apparatus of claim 1 further comprising a medium fastened to the first RFID device and the second antenna.

12. The apparatus of claim 11 wherein the medium is a member of the group consisting of plastic and polyurethane.

13. The apparatus of claim 1 wherein the first and second RFID devices are passive.

34. The apparatus of claim 1 wherein the input signal is modulated to an ultrahigh frequency range.

35. The apparatus of claim 34 wherein the input signal is modulated to 864 MHz-928 MHz.

14. An apparatus comprising:

a first radio frequency identification (RFID) device having a first antenna and a first circuit coupled to the first antenna; and

a second RFID device having a second antenna and a second circuit coupled to the second antenna, wherein the second antenna is separated from both the first RFID device and the first antenna, and the second antenna includes a primary surface overlaying at least a portion of the first circuit.

15. The apparatus of claim 14 further comprising:

multiple, additional RFID devices, wherein each additional RFID device includes a separate antenna coupled to a circuit, and each of the antennas of at least a subset of the RFID devices include a primary surface that overlays at least a portion of another one of the RFID devices.

16. The apparatus of claim 15 wherein the RFID devices are configured into a wristband.

17. The apparatus of claim 15 wherein the first RFID device and the second antenna are disposed in separate planes.

18. The apparatus of claim 14 wherein the first antenna includes a primary surface overlaying at least a portion of the second circuit.

19. The apparatus of claim 14 wherein the first circuit comprises a processor, a memory, and a transmitter and the second circuit comprises a processor, a memory, and a transmitter.

20. The apparatus of claim 14 further comprising a medium disposed between the first RFID device and the second antenna.

21. The apparatus of claim 20 wherein the medium is a member of the group consisting of plastic and polyurethane.

22. The apparatus of claim 14 wherein the second antenna is positioned to increase a maximum effective range of the first RFID device.

23. The apparatus of claim 14 wherein the primary surface of the second antenna overlays between 0% to, and including, 100% of the first circuit of the first RFID device.

24. The apparatus of claim 14 wherein the first and second RFID devices are passive.

25. The apparatus of claim 14 wherein the primary surface of the second antenna is separated from the first RFID device by a gap distance X, and 0.002 inches≦

X≦

0.008 inches.

36. The apparatus of claim 14 wherein the first and second antennas are configured to receive an input signal modulated to an ultrahigh frequency range.

37. The apparatus of claim 36 wherein the input signal is modulated to 864 MHz-928 MHz.

26. A method comprising:

receiving an input signal with a first radio frequency identification (RFID) device, wherein the RFID device includes a first antenna and a first circuit coupled to the first antenna;

receiving the input signal with a second RFID device, wherein the second RFID device includes a second antenna and a second circuit coupled to the antenna, and the second antenna is separated from both the first RFID device and the first antenna;

inducing a current in the first RFID device with the second antenna upon receipt of the input signal by the second antenna.

27. The method of claim 26 further comprising:

receiving the input signal with at least one of multiple, additional RFID devices, wherein each additional RFID device includes a separate antenna coupled to a circuit, and each of the antennas of at least a subset of the RFID devices is positioned with respect to another one of the RFID devices to induce a current in the RFID device that can be detected by the circuit of the RFID device upon receipt of the input signal.

28. The method of claim 26 wherein the second antenna includes a primary surface overlaying at least a portion of the first circuit.

29. The method of claim 28 wherein the primary surface of the second antenna is separated from the first RFID device by a gap distance X, and 0.002 inches≦

X≦

0.008 inches.

30. The method of claim 28 wherein the primary surface of the second antenna overlays between 0% to, and including, 100% of the first circuit of the first RFID device.

31. The method of claim 26 wherein the first and second RFID devices are passive.

32. The method of claim 26 wherein the first antenna is positioned with the respect to the second RFID device to induce a current in the second RFID device that can be detected the second circuit upon receipt of the input signal.

33. The method of claim 27 wherein the first circuit comprises a processor, a memory, and a transmitter and the second circuit comprises a processor, a memory, and a transmitter.