Shielded antenna to reduce electromagnetic interference (EMI) and radio frequency (RF) interference in a wireless power transfer system

• US 10,068,704 B2
• Filed: 06/23/2016
• Issued: 09/04/2018
• Est. Priority Date: 06/23/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jeong, Seong Heon
• Primary Examiner(s): Tso, Edward
• Application Number:
  US15/190,346
• Publication Number:
  US 20170372836A1
• Time in Patent Office: 803 Days
• Field of Search: 320107, 320108, 320114, 320115, 320116, 307104
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/361 made of combinations of electrically conductive material and ferromagnetic material
• CPC Class Codes: H01F 27/363 made of electrically conductive material
• CPC Class Codes: H01F 27/366 made of ferromagnetic material
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/526 Electromagnetic shields
• CPC Class Codes: H01Q 7/06 with core of ferromagnetic material H01Q7/02 takes precedence
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/0044 specially adapted for holding portable devices containing batteries H02J7/0045 takes precedence

Abstract

An apparatus for wireless power transfer includes a transmit antenna configured to generate a wireless field to power or charge a load, a wireless charging area configured to receive a device to be wirelessly charged via the wireless field, the transmit antenna located outside of a periphery of the wireless charging area, and at least one shielding element overlapping the transmit antenna on a side of the transmit antenna from which the device is configured to be positioned within the wireless charging area, the at least one shielding element configured to diminish at least a portion of the wireless field such that the wireless field in the wireless charging area is stronger than the wireless field where the at least one shielding element overlaps the transmit antenna.

Claims

1. An apparatus for wireless power transfer, the apparatus comprising:

a transmit antenna configured to generate a wireless field to power or charge a load;

a wireless charging area configured to receive a device to be wirelessly charged via the wireless field, the transmit antenna located outside of a periphery of the wireless charging area;

at least one shielding element overlapping the transmit antenna on a side of the transmit antenna from which the device is configured to be positioned within the wireless charging area, the at least one shielding element configured to diminish at least a portion of the wireless field such that the wireless field in the wireless charging area is stronger than the wireless field where the at least one shielding element overlaps the transmit antenna; and

an additional transmit antenna associated with the wireless charging area, the additional transmit antenna configured to increase a strength of the wireless field in the wireless charging area while allowing a diminished wireless field to remain where the at least one shielding element overlaps the transmit antenna.

2. The apparatus of claim 1, wherein the transmit antenna comprises a single coil surrounding the wireless charging area.

3. The apparatus of claim 1, wherein the transmit antenna comprises two series-coupled coils spanning the wireless charging area.

4. The apparatus of claim 1, wherein the transmit antenna comprises two parallel-coupled coils spanning the wireless charging area.

5. The apparatus of claim 1, wherein the transmit antenna comprises a vertically oriented coil having windings that are stacked on top of each other in separate planes.

6. The apparatus of claim 1, wherein the at least one shielding element is located away from the wireless charging area.

7. The apparatus of claim 1, wherein the shielding element is a magnetic field shielding element.

8. The apparatus of claim 1, wherein the shielding element is an electric field shielding element.

9. The apparatus of claim 7, wherein the magnetic field shielding element comprises a ferrite material located one of above and below the transmit antenna.

10. The apparatus of claim 7, wherein the magnetic field shielding element comprises a ferrite material located above and below the transmit antenna.

11. The apparatus of claim 8, wherein the electric field shielding element comprises a metal material located adjacent the transmit antenna.

12. The apparatus of claim 8, wherein the electric field shielding element diminishes an electric field in the wireless charging area while allowing a magnetic field to remain undiminished in the wireless charging area.

13. A device for wireless power transfer, comprising:

means for generating a wireless field to power or charge a load in a wireless charging area;

means for receiving a device to be wirelessly charged via the wireless field;

means for diminishing at least a portion of the wireless field outside of the wireless charging area such that the wireless field in the wireless charging area is stronger than the wireless field outside of the wireless charging area; and

means for increasing a strength of the wireless field in the wireless charging area while allowing a diminished wireless field to remain outside of the wireless charging area.

14. The device of claim 13, wherein the means for diminishing at least a portion of the wireless field outside of the wireless charging area comprises means for diminishing a magnetic field.

15. The device of claim 13, wherein the means for diminishing at least a portion of the wireless field outside of the wireless charging area comprises means for diminishing an electric field.

16. The device of claim 13, wherein the means for diminishing at least a portion of the wireless field outside of the wireless charging area comprises means for diminishing an electric field and means for allowing a magnetic field to remain undiminished.

17. An apparatus for wireless power transfer, the apparatus comprising:

a transmit coil configured to generate a wireless field to power or charge a load;

a wireless charging area configured to receive a device to be wirelessly charged via the wireless field, the transmit coil located outside of a periphery of the wireless charging area;

at least one shielding element covering the transmit coil on at least one side of the transmit coil, the one side of the coil corresponding to a side from which receiver devices will be positioned within the wireless charging area; and

an additional transmit coil associated with the wireless charging area, the additional transmit coil configured to increase a strength of the wireless field in the wireless charging area while allowing a diminished wireless field to remain outside of the wireless charging area.

18. The apparatus of claim 17, wherein the at least one shielding element comprises a first ferrite element located above the transmit coil and a second ferrite element located below the transmit coil.

19. The apparatus of claim 17, wherein the at least one shielding element is configured to magnetically shield the transmit coil to diminish at least a portion of the wireless field outside of the wireless charging area such that the wireless field in the wireless charging area is stronger than the wireless field outside of the wireless charging area.