Wireless power transmission system
Various aspects of the subject technology include a wireless power transmission design based on extended range near-field resonance coupling induction, where magnetic near-field range may be extended by several orders of magnitude. One element that may help to accomplish the near-field extension, in one aspect, is the addition of a transformational magnetic lens to the transmitter. The magnetic lens may be made of metamaterials with refractive index of for example, −1. It may recover and collimate the near-field evanescent, magnetic flux, effectively extending the near-field coupling distance by several orders of magnitude.
1. A system for wireless power transmission, the system comprising:
a source coil configured to convert power provided by a power source into a magnetic field;
a metamaterial magnetic lens comprising a plurality of unit cell structures arranged in a superlattice, each unit cell structure of the plurality of unit cell structures comprising a split-ring resonator; and
at least one transmit coil, coupled to the source coil, configured to transmit the magnetic field through the metamaterial magnetic lens, wherein the magnetic field exhibits a magnetic flux,
wherein the metamaterial magnetic lens is configured to collimate the magnetic flux of the magnetic field transmitted by the at least one transmit coil towards a receiver of a load.
2. The system of claim 1 , wherein the metamaterial magnetic lens has a refractive index of −1.
3. The system of claim 1 , wherein the split-ring resonator is configured to have a magnetic permeability of −1.
4. The system of claim 1 , wherein each unit cell structure comprises a cross-wire structure comprising two slits.
5. The system of claim 4 , wherein the cross-wire structure is configured to have a dielectric permittivity of −1.
6. The system of claim 1 , wherein the source coil comprises at least one microelectromechanical (MEM) switchable resistor configured to provide impedance matching between the power source and a load.
7. The system of claim 1 , wherein each of the at least one transmit coil comprises at least one microelectromechanical (MEM) varactor configured to tune a resonance frequency of at least one transmit coil to match that of at least one receive coil.
8. The system of claim 1 , wherein the at least one transmit coil and the metamaterial magnetic lens are implemented on a printed circuit board (PCB) substrate.
9. The system of claim 1 , wherein the system is configured to operate with a receiver comprising at least one receive coil coupled with a load coil to convert the magnetic field back to electrical power to be used by the load, wherein the magnetic field transmitted by the at least one transmit coil is able to wirelessly induce a current in the at least one receiver coil.
10. A method for wirelessly transmitting power, the method comprising:
transmitting power from a source through a source coil configured to convert the power provided by the power source into a magnetic field;
converting, at the source coil, the power into a magnetic field; and
using a transmit coil to transmit the magnetic field through a metamaterial magnetic lens comprising a plurality of unit cell structures arranged in a superlattice, each unit cell structure of the plurality of unit cell structures comprising a split-ring resonator,
wherein the magnetic field is transmitted at a resonance frequency of the transmit coil and the resonance frequency of the transmit coil is configured to correspond to that of a receive coil, and
wherein the metamaterial magnetic lens is configured to collimate the magnetic field transmitted by the transmit coil towards the receiver coil.
11. The method of claim 10 , wherein the metamaterial magnetic lens has a refractive index of −1.
12. The method of claim 10 , further comprising using a receive coil to receive the magnetic field, wherein the receive coil is coupled to a load coil to convert magnetic energy of the magnetic field to electrical power.
13. A system for wireless power transmission, the system comprising:
a source coil configured to convert the electrical energy into a magnetic field;
a transmit coil, coupled to the source coil, configured to transmit the magnetic field wherein the magnetic field exhibits a magnetic flux; and
a metamaterial magnetic lens comprising a plurality of unit cell structures arranged in a superlattice, each unit cell structure of the plurality of unit cell structures comprising a split-ring resonator, wherein the metamaterial magnetic lens is configured to collimate the magnetic flux of the magnetic field transmitted by the transmit coil.
14. The system of claim 13 , further comprising:
a power source configured to provide the electrical energy,
wherein the system is configured to operate with a receiver a receive coil coupled to a load coil, the receive coil configured to receive the magnetic flux and convert the magnetic energy back to electrical energy, and
wherein the receive coil and the load coil are implemented on a printed circuit board (PCB) substrate.
15. The system of claim 13 , wherein the metamaterial magnetic lens has a refractive index of −1.
16. The system of claim 13 , wherein each split-ring resonator has a magnetic permeability of −1 and a cross-wire structure having a dielectric permittivity of −1.
17. The system of claim 16 , wherein the split-ring resonator and the cross-wire structure are made of copper, and wherein the split-ring resonator is square shaped.
18. The system of claim 13 , wherein the source coil, the transmit coil, and the metamaterial magnetic lens are implemented on a printed circuit board (PCB) substrate.