FERRITE ANTENNAS FOR WIRELESS POWER TRANSFER

• US 20110095617A1
• Filed: 06/05/2009
• Published: 04/28/2011
• Est. Priority Date: 06/05/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Schwaninger, Peter, Widmer, Hanspeter, Sieber, Lukas, Cook, Nigel P.
• Granted Patent: US 8,253,278 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01Q 7/08 Ferrite rod or like elongated core
• CPC Class Codes: H02J 50/12 of the resonant type

Abstract

Ferrite core antenna used for transmitting or receiving wireless power. The antenna can move relative to the core.

Claims

1. A wireless power system, comprising:

a connection to a signal having a first frequency, said signal carrying a specified power level;

an inductive part, formed of a loop base, and a main inductive loop that has a first specified number of loop turns, and a coupling loop having a second number of loop turns, said coupling loop having fewer loop turns than said main loop, and said connection being electrically coupled to said coupling loop and not to said main inductive loop, said coupling loop and said main loop being physically coupled to one another and being movable relative to said loop base, such that both said main loop and said coupling loop move together on said loop base.

2. A system as in claim 1, further comprising a circuit that receives wireless power at a frequency that is resonant with said main inductive loop, and creates a power output, coupled to receive an output from said coupling loop.

3. A system as in claim 1, further comprising a circuit that creates a power output, at a frequency that is resonant with said main inductive loop, and couples said power output to said coupling loop to transmit wireless power.

4. A system as in claim 1, wherein said connection includes a plurality of flexible wires, that connect to the coupling loop, wherever it is moved on said loop base.

5. A system as in claim 1, wherein said inductive part is formed with a ferrite core.

6. A system as in claim 1, wherein a number of windings on the coupling loop is used to set an input impedance of the system.

7. A system as in claim 1, further comprising a capacitance, coupled across said main inductive loop.

8. A system as in claim 7, wherein said capacitance has a value such that an LC value of said inductance and capacitance together is resonant with a specified frequency.

9. A system as in claim eight, wherein said specified frequency is 135 kHz.

10. A method of transmitting wireless power, comprising:

optimizing a first coupling loop part of an antenna;

attaching a main inductive loop mechanically to the first coupling loop and keeping said main loop and said coupling loop electrically isolated from one another;

optimizing the main loop of the antenna separately from optimizing the coupling loop;

moving both the coupling loop and the main loop to different locations, to optimize their position relative to parameters of a circuit; and

using the coupling loop and main loop as attached to one another to transmit wireless power.

11. A method as in claim 10, wherein said coupling loop is optimized according to a desired input impedance of the antenna.

12. A method of as in claim 10, further comprising coupling a capacitor across the main loop, wherein said main loop and said capacitor collectively create an LC constant which is resonant with a specified frequency of said transmission of wireless power.

13. A method as in claim 12, wherein said specified frequency is 135 kHz.

14. A method as in claim 12, further comprising moving the connected coupling loop and main loop to different locations to optimize a characteristic of the coupling loop and main loop.

15. A method as in claim 14, further comprising winding the coupling loop and the main loop on a core, and wherein said moving is relative to said core.

16. A method as in claim 15, wherein said core is a ferrite core.

17. A method of receiving wireless power, comprising:

optimizing a first coupling loop part of an antenna;

attaching a main inductive loop mechanically to the first coupling loop and keeping said main loop and said coupling loop electrically isolated from one another;

optimizing the main loop of the antenna separately from optimizing the coupling loop;

moving both the coupling loop and the main loop to different locations, to optimize their position relative to parameters of a circuit that is to receive the wireless power and be powered thereby; and

using the coupling loop and main loop as attached to one another to receive wireless power.

18. A method as in claim 17, wherein said coupling loop is optimized according to a desired input impedance of the antenna.

19. A method of as in claim 17, further comprising coupling a capacitor across the main loop, wherein said main loop and said capacitor collectively create an LC constant which is resonant with a specified frequency of said transmission of wireless power.

20. A method as in claim 19, wherein said specified frequency is 135 kHz.

21. A method as in claim 19, further comprising moving the connected coupling loop and main loop to different locations to optimize a characteristic of the coupling loop and main loop.

22. A method as in claim 21, further comprising winding the coupling loop and the main loop on a core, and wherein said moving is relative to said core.

23. A method as in claim 17, wherein said core is a ferrite core.