Multi-band wireless communication device and method

• US 7,899,425 B2
• Filed: 02/25/2009
• Issued: 03/01/2011
• Est. Priority Date: 10/03/2000
• Status: Expired due to Fees

• Current Assignee: Mineral Lassen LLC (Intellectual Ventures LLC)
• Original Assignee: Mineral Lassen LLC (Intellectual Ventures LLC)
• Inventors: Forster, Ian J.
• Primary Examiner(s): Yun; Eugene
• Application Number:
  US12/392,986
• Publication Number:
  US 20090153303A1
• Time in Patent Office: 734 Days
• Field of Search: 455/272, 455/101, 455/274, 455/275, 455/277.1, 455/277.2, 455/279.1, 455/562.1, 455/575.7, 455/269, 343/728, 343/729, 343/732, 343/737, 343/751, 343/764, 343/866, 343/853, 343/855
• US Class Current: 455/269
• CPC Class Codes: G06K 19/0724 the arrangement being a circuit for communicating at a plurality of frequencies, e.g. for managing time multiplexed communication over at least two antennas of different types
• 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 19/07767 the first and second communication means being two different antennas types, e.g. dipole and coil type, or two antennas of the same kind but operating at different frequencies
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole
• 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 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/45 Transponders
• CPC Class Codes: H04B 5/77 for interrogation
• CPC Class Codes: H04B 7/12 Frequency diversity

Abstract

The present invention relates to a wireless communication device, such as a transponder, that has a plurality of antennas for multi-frequency usage. The wireless communication device comprises a control system, communication electronics, memory, and the aforementioned antennas. A wireless communication device having a pole antenna may be used with one or more loop conductor antennas to achieve the desired operating frequencies. A wireless communication device having a dipole antenna may be coupled across a loop conductor antenna to provide different loop conductor configurations depending on the frequency.

Claims

1. A wireless communication device, comprising:

communication electronics connected to a pole antenna having at least one tab;

a first loop antenna positioned proximate to the pole antenna and capacitively coupled to the pole antenna at a first frequency, wherein the capacitive coupling forms a first resonant circuit between the communication electronics and the first loop antenna configured to operate at the first frequency; and

a second loop antenna positioned proximate to the pole antenna and capacitively coupled to the pole antenna at a second frequency, wherein the capacitive coupling forms a second resonant circuit between the communication electronics and the second loop antenna configured to operate at the second frequency;

wherein the communication electronics and the pole antenna form a third resonant circuit configured to operate at a third frequency that is different from the first and second frequencies.

2. The wireless communication device of claim 1, wherein the pole antenna is positioned between the first loop antenna and the second loop antenna, and wherein the first and second frequencies of the first and second resonant circuits are tuned according to the relative placement of the pole antenna between the first and second loop antennas.

3. The wireless communication device of claim 1, wherein the first loop antenna and the second loop antenna are formed of a microstrip.

4. The wireless communication device of claim 1, wherein the pole antenna is a dipole antenna having at least two tabs, and wherein the first and second loop antennas comprise tuned coils in which the tabs of the dipole antenna are placed across the coils to capacitively couple the tabs to the coils at the first and second frequencies.

5. The wireless communication device of claim 4, wherein the tabs are asymmetrically shaped to form an asymmetrical dipole antenna.

6. The wireless communication device of claim 4, wherein the first loop antenna and the second loop antenna form a pair of asymmetrical loop antennas in which the first loop antenna is smaller than the second loop antenna according to the position where the tabs of the dipole antenna are placed across the coils.

7. The wireless communication device of claim 1, wherein a slotted ground plane is positioned between the pole antenna and the first and second loop antennas.

8. The wireless communication device of claim 1, wherein at least one of the first loop antenna and the second loop antenna is formed of a first loop part and a second loop part that are both capacitively coupled to the pole antenna, and wherein the second loop part is nested within the first loop part.

9. The wireless communication device of claim 1, wherein the first loop antenna is formed to be electrically longer than the second loop antenna, and wherein the first frequency of the first resonant circuit is lower than the second frequency of the second resonant circuit.

10. The wireless communication device of claim 1, wherein a slotted ground plane is positioned between the pole antenna and the first and second loop antennas, and wherein the slotted ground plane comprises two plates positioned with a gap therebetween.

11. The wireless communication device of claim 10, wherein the first frequency of the first resonant circuit is UHF, the second frequency of the second resonant circuit is a low frequency, and the third frequency of the third resonant circuit is a microwave frequency.

12. The wireless communication device of claim 11, wherein the gap in the slotted ground plane has a low impedance at the third frequency.

13. A method of providing a wireless communication device, the method comprising:

providing a pole antenna having at least one tab;

connecting communication electronics to the pole antenna;

positioning a first loop antenna proximate to the pole antenna to capacitively couple the first loop antenna to the pole antenna at a first frequency such that the capacitive coupling forms a first resonant circuit between the communication electronics and the first loop antenna at the first frequency; and

positioning a second loop antenna proximate to the pole antenna to capacitively couple the second loop antenna to the pole antenna at a second frequency such that the capacitive coupling forms a second resonant circuit between the communication electronics and the second loop antenna at the second frequency;

wherein the communication electronics and the pole antenna form a third resonant circuit configured to operate at a third frequency that is different from the first and second frequencies.

14. The method of claim 13, further comprising positioning the pole antenna between the first loop antenna and the second loop antenna, wherein the first and second frequencies of the first and second resonant circuits are tuned according to the relative placement of the pole antenna between the first and second loop antennas.

15. The method of claim 13, wherein the first loop antenna and the second loop antenna are formed of a microstrip.

16. The method of claim 13, wherein the pole antenna is a dipole antenna having at least two tabs, and wherein the first and second loop antennas comprise tuned coils in which the tabs of the dipole antenna are placed across the coils to capacitively couple the tabs to the coils at the first and second frequencies.

17. The method of claim 16, wherein the tabs are asymmetrically-shaped to form an asymmetrical dipole antenna.

18. The method of claim 16, wherein the first loop antenna and the second loop antenna form a pair of asymmetrical loop antennas in which the first loop antenna is smaller than the second loop antenna according to the position where the tabs of the dipole antenna are placed across the coils.

19. The method of claim 13, further comprising positioning a slotted ground plane between the pole antenna and the first and second loop antennas.

20. The method of claim 13, wherein at least one of the first loop antenna and the second loop antenna is formed of a first loop part and a second loop part that are both capacitively coupled to the pole antenna, and wherein the second loop part is nested within the first loop part.

21. The method of claim 13, wherein the first loop antenna is formed to be electrically longer than the second loop antenna, and wherein the first frequency of the first resonant circuit is lower than the second frequency of the second resonant circuit.

22. The method of claim 13, further comprising positioning a slotted ground plane between the pole antenna and the first and second loop antennas, wherein the slotted ground plane comprises two plates positioned with a gap therebetween.

23. The method of claim 22, wherein the first frequency of the first resonant circuit is UHF, the second frequency of the second resonant circuit is a low frequency, and the third frequency of the third resonant circuit is a microwave frequency.

24. The method of claim 23, wherein the gap in the slotted ground plane has a low impedance at the third frequency.