NEAR FIELD TRANSMITTERS FOR WIRELESS POWER CHARGING

• US 20170187224A1
• Filed: 02/17/2016
• Published: 06/29/2017
• Est. Priority Date: 12/24/2015
• Status: Active Grant

• Current Assignee: Energous Corporation
• Original Assignee: Energous Corporation
• Inventors: HOSSEINI, Alister, LEABMAN, Michael A.
• Granted Patent: US 10,277,054 B2
• Time in Patent Office: Days
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals

Abstract

Disclosed is a system including RF circuitry configured to generate an RF signal; a plurality of unit cells configured to receive the RF signal and to cause an RF energy signal having a center frequency to be present within the unit cells; and receiver circuitry configured to charge an electronic device in response to an antenna of the electronic device receiving the RF energy signal when the antenna is tuned to the center frequency and positioned in a near-field distance from one or more of the unit cells.

Claims

1. A method for charging an electronic device, the method comprising:

receiving a signal indicative of a request for charging the electronic device;

generating, in response to receiving the signal, an RF signal;

applying the RF signal to a plurality of unit cells of a charging surface to cause an RF energy signal to be present in the unit cells of the charging surface for charging the electronic device; and

leaking the RF energy signal from the unit cells of the charging surface to an antenna of the electronic device when the antenna is positioned in a near-field distance to at least one of the unit cells.

2. The method of claim 1, wherein the signal indicative of the request for charging the electronic device is received using a wireless communication protocol including at least one of Bluetooth®

, Wi-Fi®

, Zigbee®

, or FM radio signal.

3. The method of claim 1, wherein the unit cells include a metamaterial.

4. The method of claim 1, wherein the near-field distance is less than about 4 mm.

5. The method of claim 1, wherein receiving the signal indicative of the request for charging the electronic device includes receiving a power limit of the electronic device.

6. The method of claim 5, wherein the RF energy signal is configured to produce a power conforming with the power limit.

7. The method of claim 1, wherein the RF energy signal operates at a center frequency and the unit cells of the charging surface are configured to leak the RF energy signal to the antenna of the electronic device when the antenna is tuned to the center frequency.

8. A charging surface device comprising:

control circuitry configured to receive a signal indicative of a request for charging an electronic device;

a plurality of patch antennas each configured to generate an RF energy signal; and

a plurality of unit cells configured to leak the RF energy signal from the unit cells when an antenna of the electronic device is tuned to the center frequency and positioned in a near-field distance from at least one of the unit cells.

9. The device of claim 8, wherein the control circuitry is further configured to cause at least one of the plurality of patch antennas to generate the RF energy signal in response to receiving the signal indicative of the request for charging the electronic device.

10. The device of claim 8, wherein the RF energy signal operates at a center frequency and the unit cells are configured to leak the RF energy signal to the antenna of the electronic device when the antenna is tuned to the center frequency.

11. The device of claim 8, wherein the near-field distance is less than about 4 mm.

12. The device of claim 8, wherein the unit cells include a metamaterial.

13. The device of claim 8, wherein the signal indicative of the request for charging the electronic device is received by the control circuitry using a wireless communication protocol including at least one of Bluetooth, Wi-Fi, Zigbee, or FM radio signal.

14. The device of claim 8, wherein the signal indicative of the request for charging the electronic device includes a power limit of the electronic device.

15. The device of claim 14, wherein the RF energy signal is configured to produce a power conforming with the power limit.

16. A method for charging an electronic device, the method comprising:

producing a low-power RF energy signal in a unit cell of a charging surface;

leaking the low-power RF energy signal from the unit cell of the charging surface to an antenna of the electronic device when the antenna is positioned in a near-field distance from the unit cell;

sensing the low-power RF energy signal in the unit cell of the charging surface;

comparing the low-power RF energy signal in the unit cell of the charging surface to a threshold level; and

producing, if the low-power RF energy signal is below the threshold level, a subsequent low-power RF energy signal in the unit cell of the charging surface.

17. The method of claim 16, wherein the low-power RF energy signal operates at a center frequency and the unit cell of the charging surface is configured to leak the low-power RF energy signal to the antenna of the electronic device when the antenna is tuned to the center frequency.

18. The method of claim 16, wherein sensing the low-power RF energy signal in the unit cell of the charging surface comprises utilizing an RF coupler to sense a power level of the low-power RF energy signal.

19. The method of claim 16, wherein the low-power RF energy signal is less than about 0.5 W.

20. The method of claim 16, wherein the near-field distance is less than about 4 mm.

21. The method of claim 16, further comprising:

detecting a signal indicative of a request for charging the electronic device, the signal indicating a power limit;

producing, in response to the signal, an RF energy signal in the unit cell of the charging surface, the RF energy signal configured to produce a power conforming with the power limit; and

leaking the RF energy signal from the unit cell of the charging surface to the antenna of the electronic device when the antenna is positioned in the near-field distance to the unit cell of the charging surface.

22. The method of claim 21, wherein the RF energy signal operates at a center frequency and the unit cell of the charging surface is configured to leak the RF energy signal to the antenna of the electronic device when the antenna is tuned to the center frequency.

23. A charging surface device comprising:

a patch antenna configured to produce a low-power RF energy signal;

a unit cell inclusive of the patch antenna, the unit cell configured to retain the low-power RF energy signal when an antenna of an electronic device is not positioned in a near-field distance from the unit cell, and configured to leak the low-power RF energy signal when the antenna of the electronic device is positioned in the near-field distance from the unit cell; and

control circuitry configured to sense the low-power RF energy signal in the unit cell, compare the low-power RF energy signal to a threshold, and to cause, if the low-power RF energy signal is below the threshold, the patch antenna to produce a subsequent low-power RF energy signal stored in the unit cell.

24. The device of claim 23, wherein the low-power RF energy signal is less than about 0.5 W.

25. The device of claim 23, wherein the near-field distance is less than about 4 mm.

26. The device of claim 23, wherein the low-power RF energy signal operates at a center frequency and the unit cell is configured to leak the low-power RF energy signal when the antenna of the electronic device is tuned to the center frequency and positioned in the near-field distance from the unit cell.

27. The device of claim 23, wherein the subsequent low-power RF energy signal operates at a center frequency and the unit cell is configured to leak the subsequent low-power RF energy signal when the antenna of the electronic device is tuned to the center frequency and positioned in the near-field distance from the unit cell.

28. The device of claim 23, wherein the control circuitry is further configured to receive a signal indicative of a request for charging the electronic device.

29. The device of claim 28, wherein the signal indicates a power limit and the control circuitry is further configured to cause the patch antenna to produce an RF energy signal in the unit cell, the RF energy signal configured to produce a power conforming with the power limit.

30. The device of claim 29, wherein RF energy signal operates at a center frequency and the unit cell is configured to leak the RF energy signal when the antenna of the electronic device is tuned to the center frequency and positioned in the near-field distance from the unit cell.