Wireless energy transfer with negative index material

• US 9,461,505 B2
• Filed: 12/03/2009
• Issued: 10/04/2016
• Est. Priority Date: 12/03/2009
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Teo, Koon Hoo, Huang, Da, Wang, Bingnan
• Primary Examiner(s): Amrany, Adi
• Application Number:
  US12/630,498
• Publication Number:
  US 20110133564A1
• Time in Patent Office: 2,497 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: B66B 7/00 Other common features of elevators
• 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 50/12 of the resonant type
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A system exchanges energy wirelessly and includes a structure configured to exchange the energy wirelessly via a coupling of evanescent waves. The structure is non-radiative, and generates an electromagnetic (EM) near-field in response to receiving the energy. A negative index material (NIM) is arranged within the EM near-field such that the coupling is enhanced.

Claims

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

a source structure and a sink structure exchanging the energy wirelessly via a coupling of evanescent waves, wherein the source structure and the sink structure are non-radiative and generate an electromagnetic (EM) near-field during the exchanging of the energy, wherein a strength of the coupling is represented by a coupling coefficient, and wherein the source structure and the sink structure are resonant structures, such that the system is a resonant system with a resonant frequency; and

a negative index material (NIM) arranged within the EM near-field to increase the coupling coefficient, wherein the NIM is a resonant structure and has negative electromagnetic properties at the resonant frequency.

2. The system of claim 1, further comprising:

a driver supplying the energy to the source structure.

3. The system of claim 1, further comprising:

a load receiving the energy from the sink structure.

4. The system of claim 1, wherein the energy has a frequency in a diapason from MHz to GHz.

5. The system of claim 1, wherein the NIM is arranged optimally based on a desired direction of the energy transfer.

6. The system of claim 1, wherein the NIM is arranged such as to enclose at least one of the source structure or the sink structure.

7. The system of claim 1, wherein a plurality of NIMs arranged on a path of an evanescent wave such that the evanescent wave travels through each NIM in the plurality of NIMs during the coupling.

8. The system of claim 1, wherein the NIM is arranged such that a distance between the NIM and at least one of the source structure or the sink structure is proportional to dimensions of the NIM.

9. A method for exchanging energy wirelessly via a coupling of evanescent waves, wherein a strength of the coupling is represented by a coupling coefficient, comprising:

providing a structure for exchanging the energy wirelessly via the coupling, wherein the Structure is non-radiative and resonant at a resonant frequency, and wherein the structure generates the evanescent waves in response to receiving the energy; and

increasing the coupling coefficient using a negative index material (NIM) arranged on a path of the coupled evanescent waves, wherein the NIM has negative electromagnetic properties at the resonant frequency.

10. The method of claim 9, wherein the structure is a source configured to transfer the energy to a sink, further comprising:

supplying the energy to the structure.

11. The method of claim 9, wherein the energy is supplied inductively.

12. The method of claim 9, wherein the structure is a sink configured to receive the energy wirelessly, further comprising:

supplying the energy to a load.

13. The method of claim 9, further comprising:

arranging a plurality of NIMs on the path of the coupled evanescent waves.

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

a source structure and a sink structure exchanging the energy wirelessly via a coupling of evanescent waves, wherein the source structure is an electromagnetic (EM) and a non-radiative; and

a negative index material (NIM) arranged on a path of the coupled evanescent waves, such that the NIM increases a coupling coefficient of the coupling, wherein the source structure is a resonant structure having a resonant frequency, and the NIM has a negative permittivity property and a negative permeability property within a bandwidth of about 5-10% of the resonant frequency.

15. The system of claim 14, wherein the NIM is arranged such as to enclose the source structure.