MINIATURIZED HIGHLY-EFFICIENT DESIGNS FOR NEAR-FIELD POWER TRANSFER SYSTEM

• US 20170187422A1
• Filed: 09/19/2016
• 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 10,320,446 B2
• Time in Patent Office: Days
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• CPC Class Codes: H04B 5/75 for isolation purposes
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Near-field power transfer systems can include antenna elements that constructed or printed close to each other in a meandered arrangement, where neighboring antenna elements conduct currents that flow in opposite directions. This current flow entirely or almost entirely cancels out any far field RF radiation generated by the antennas or otherwise generated by the electromagnetic effects of the current flow. For a first current flowing in a first path, there may be a second current flowing in a second cancellation path, which cancels the far field radiation produced by the first current flowing in the first path. Therefore, there may be no radiation of power to the far field. Such cancellation, may not occur in a near-field active zone, where the transfer of power may occur between the transmitter and the receiver. A ground plane may block the leakage of power from the back of a transmitter and/or a receiver.

Claims

1. A near-field radio frequency (RF) power transfer system, comprising:

a first antenna element disposed on or below a first surface of a substrate and configured to carry a first current in a first direction during a first time period to generate a first RF radiation;

a second antenna element disposed on or below the first surface of the substrate and configured to carry a second current in a second direction opposite to the first direction during the first time period to generate a second RF radiation such that the far-field portion of the second RF radiation substantially cancels the far-field portion of the first RF radiation; and

a ground plane disposed on or below a second surface of the substrate, wherein the second surface is opposite to the first surface.

2. The near-field RF power transfer system of claim 1, further comprising:

a via passing through the ground plane, wherein the via contains a power feed line configured to supply the first and the second currents.

3. The near-field RF power transfer system of claim 1, further comprising:

a first via passing through the ground plane, wherein the first via contains a first power feed line configured to supply the first current; and

a second via passing through the ground, wherein the second via contains a second power feed line configured to supply the second current.

4. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are segments of a spiral antenna.

5. The near-field RF power transfer system of claim 1, wherein the first antenna element is a segment of a first pole of a dipole antenna, and the second antenna element is a segment of a second pole of the dipole antenna.

6. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are segments of a loop antenna.

7. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are segments of a loop antenna comprising concentric loops.

8. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are segments of a monopole antenna.

9. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are segments of a hybrid dipole antenna comprising two spiral poles.

10. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are segments of hierarchical spiral antenna.

11. The near-field RF power transfer system of claim 1, wherein the ground plane is constructed of a solid metal sheet of copper or a copper alloy.

12. The near-field RF power transfer system of claim 1, wherein the ground plane is constructed of metal strips arranged in shapes selected from the group consisting of a loop, a spiral, and a mesh.

13. The near-field RF power transfer system of claim 1, wherein the first and second antenna elements are constructed of copper or a copper alloy.

14. The near-field RF power transfer system of claim 1, wherein the far-field portion of the first RF radiation cancels out the far-field portion of a second RF radiation.

15. The near-field RF power transfer system of claim 1, wherein the ground plane is configured to reflect at least a portion of the RF radiation generated by the first and second antenna elements.

16. The near-field RF power transfer system of claim 1, wherein the ground plane is configured to cancel at least a portion of the RF radiation generated by the first and second antenna elements.

17. The near-field RF power transfer system of claim 1, wherein the power transfer system is configured as a power receiver.

18. The near-field RF power transfer system of claim 1, wherein the power transfer system is configured as a power transmitter.

19. The near-field RF power transfer system of claim 1, wherein the substrate comprises a metamaterial of a predetermined magnetic permeability or electrical permittivity.

20. A method of near-field RF power transfer, the method comprising:

supplying, through one or more vias through a ground plane, a first current to a first antenna element such that the first antenna generates a first RF radiation and a second current to a second antenna element such that the second antenna generates a second RF radiation,

wherein the first current is in a first direction and the second current is in a second direction opposite to the first direction such that the far-field portion of the second RF radiation substantially cancels the far field portion of the first RF radiation,

wherein the first and second antenna elements are disposed on or below a first surface of a substrate, and

wherein the ground plane is disposed on or below a second surface of the substrate opposite to the first surface.