Wireless Energy Transfer with Anisotropic Metamaterials

• US 20120038219A1
• Filed: 02/15/2011
• Published: 02/16/2012
• Est. Priority Date: 03/25/2010
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Wang, Bingnan, Teo, Koon Hoo, Yerazunis, William
• Granted Patent: US 8,786,135 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B66B 7/00 Other common features of elevators
• CPC Class Codes: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Embodiments of the invention disclose a system configured to exchange energy wirelessly. The system includes a structure configured to exchange the energy wirelessly via a coupling of evanescent waves, wherein the structure is electromagnetic (EM) and non-radiative, and wherein the structure generates an EM near-field in response to receiving the energy; and an anisotropic metamaterial arranged within the EM near-field such that the coupling is enhanced.

Claims

1. A system configured to exchange energy wirelessly, comprising:

a structure configured to exchange the energy wirelessly via a coupling of evanescent waves, wherein the structure is electromagnetic (EM) and non-radiative, wherein the structure generates an EM near-field in response to receiving the energy; and

an anisotropic metamaterial arranged within the EM near-field such that an amplitude of the evanescent waves is increased.

2. The system of claim 1, wherein the structure is a source configured to transfer the energy to a sink, further comprising:

a driver configured to supply the energy to the structure.

3. The system of claim 1, wherein the structure is a sink configured to receive the energy wirelessly from a source, further comprising:

a load configured to receive the energy from the structure.

4. The system of claim 1, wherein dimensions of the structure are smaller than a wavelength of the evanescent waves.

5. The system of claim 1, wherein the structure is a resonant structure.

6. The system of claim 1, wherein the anisotropic metamaterial is arranged optimally based on a desired direction of the energy transfer.

7. The system of claim 1, wherein the structure is configured to exchange the energy wirelessly along a first direction, wherein the anisotropic metamaterial has a property of a metamaterial along a second direction, and wherein the anisotropic metamaterial is arranged such that the second direction is aligned with the first direction.

8. The system of claim 1, wherein a plurality of anisotropic metamaterials is arranged on a path of an evanescent wave, such that the evanescent wave travels through each anisotropic metamaterial in the plurality of anisotropic metamaterials during the coupling.

9. The system of claim 6, wherein the anisotropic metamaterial has a negative permittivity property and a positive permeability property along a particular direction aligned with the desired direction of the energy transfer.

10. The system of claim 6, wherein the anisotropic metamaterial has a positive permittivity property and a negative permeability property along a particular direction aligned with the desired direction of the energy transfer.

11. A method of transferring electromagnetic energy wirelessly via a coupling of evanescent waves, comprising steps of:

increasing amplitudes of the evanescent waves using an anisotropic metamaterial, such that the coupling is enhanced.

12. The method of claim 11, further comprising:

providing a first resonator structure having a first mode with a resonant frequency ω

₁, an intrinsic loss rate Γ

₁ and a first Q-factor Q₁=ω

₁/(2Γ

₁), wherein the first resonator structure is electromagnetic and designed so that Q₁>

100;

providing a second structure positioned distal from the first electromagnetic resonator structure and not electrically wired to the first resonator structure, the second resonator structure has a second mode with a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, a second Q-factor Q₂=ω

₂/(2Γ

₂), wherein the second resonator structure is electromagnetic and designed so that Q₂>

100;

arranging the anisotropic metamaterial between the first resonator structure and the second resonator structure, wherein the anisotropic metamaterial has a property of a metamaterial along a particular direction aligned with a desired direction of the energy transfer; and

transferring the electromagnetic energy from the first resonator structure through the anisotropic metamaterial to the second resonator structure over a distance D, wherein the distance D is smaller than each of the resonant wavelength λ

₁ and λ

₂ corresponding to the resonant frequencies ω

₁ and ω

₂ respectively.

13. The method of claim 11, wherein the anisotropic metamaterial has a positive permittivity property and a negative permeability property only along the particular direction.

14. The method of claim 11, wherein the anisotropic metamaterial has a negative permittivity property and a positive permeability property only along the particular direction.

15. The method of claim 11, wherein the anisotropic metamaterial has a negative permittivity property and a negative permeability property only along the particular direction.

16. The method of claim 11, wherein the anisotropic metamaterial is formed by inhomogeneities having dimensions smaller than a wavelength of the evanescent waves.

17. A system configured to exchange electromagnetic energy wirelessly, comprising:

a first resonator structure having a first mode with a resonant frequency ω

₁, an intrinsic loss rate Γ

₁ and a first Q-factor Q₁=ω

₁/(2Γ

₁), wherein the first resonator structure is electromagnetic and designed so that Q₁>

100;

a second structure positioned distal from the first electromagnetic resonator structure and not electrically wired to the first resonator structure, the second resonator structure has a second mode with a resonant frequency ω

₂, an intrinsic loss rate Γ

₂, a second Q-factor Q₂=ω

₂/(2Γ

₂), wherein the second resonator structure is electromagnetic and designed to have Q₂>

100; and

an anisotropic metamaterial arranged between the first resonator structure and the second resonator structure, wherein the first resonator structure transfer the electromagnetic energy through the anisotropic metamaterial to the second resonator structure over a distance D, wherein the distance D is smaller than each of the resonant wavelength λ

₁ and λ

₂ corresponding to the resonant frequencies ω

₁ and ω

₂ respectively.

18. The system of claim 17, wherein the first resonator structure transfer the electromagnetic energy via a coupling of evanescent waves, wherein dimensions of the structure are smaller than each of the resonant wavelength λ

₁ and λ

₂, and wherein the anisotropic metamaterial is a single-negative (SNG) metamaterial only along a direction of energy transfer.

19. The system of claim 18, wherein the anisotropic metamaterial is formed by planar sheets of two-dimensional array of inhomogeneities, wherein the planar sheets are arranged in parallel.

20. The system of claim 19, wherein the planar sheets are arranged such that the direction of the energy transfer is perpendicular to the planar sheets.