Wireless energy transfer with high-Q capacitively loaded conducting loops
Described herein are embodiments of a source resonant structure and a device resonant structure, the structures may be capable of performing wireless near-field energy transfer when separated a distance D from each other, where the absolute value of the difference of said angular frequencies w 1 and w 2 may be smaller than the magnitude of the coupling rate, k, and where at least one of the resonant structures comprises a high-Q capacitively-loaded conducting-wire loop.
1. A system, comprising:
a source resonant structure and a device resonant structure, the structures capable of performing wireless near-field energy transfer with a coupling rate κ when separated a variable distance D from each other,
said source resonant structure having a resonant frequency f 1 =ω 1 /2π, an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 ), where ω 1 is the angular frequency corresponding to the resonant frequency f 1 ,
said device resonant structure having a resonant frequency f 2 =ω 2 /2π, an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω2/(2Γ 2 ), where ω 2 is the angular frequency corresponding to the resonant frequency f 2 ,
wherein the absolute value of the difference of said angular frequencies ω 1 and ω 2 is smaller than the magnitude of the coupling rate, κ, and
wherein at least one of the resonant structures comprises a high-Q capacitively-loaded conducting-wire loop.
2. The system of claim 1 , wherein the Q-factor of at least one of the resonant structures is greater than 100.
3. The system of claim 1 , wherein √{square root over (Q 1 Q 2 )}>100.
4. The system of claim 1 , wherein Q 1 >100 and Q 2 >100.
5. The system of claim 1 , further comprising a power supply coupled to the source resonant structure and an energy drain coupled to the device resonant structure.
6. The system of claim 5 , wherein the energy drain comprises a robot, vehicle, computer, cell phone, or a portable electronic device.
7. The system of claim 1 , further comprising a third resonant structure, optionally coupled to an energy drain, located at a variable distance from the source resonant structure, and wherein the source resonant structure and the third resonant structure are coupled to wirelessly transfer electromagnetic energy from the source resonant structure to the third resonant structure.
8. The system of claim 1 , further comprising a third resonant structure, optionally coupled to a power supply, located at a variable distance from the device resonant structure, and wherein the third resonant structure and the device resonant structure are coupled to wirelessly transfer electromagnetic energy from the third resonant structure to the device resonant structure.
9. The system of claim 1 , wherein at least one of the resonant structures is tunable.
10. The system of claim 1 , further comprising a feedback mechanism coupled to at least one of the resonant structures to correct for detuning.
11. The system of claim 1 , wherein the resonant structures are movable relative to one another and wherein the wireless energy transfer occurs over a range of distances.
12. The system of claim 11 , wherein the range of distances includes 5 cm.
13. The system of claim 11 , wherein the range of distances includes 10 cm.
14. The system of claim 11 , wherein the range of distances includes 30 cm.
15. The system of claim 11 , wherein the efficiency of the wireless energy transfer is at least 20% over the range of distances.
16. The system of claim 11 , wherein κ/√{square root over (Γ 1 Γ 2 )}>0.2 over the range of distances, wherein κ is the wireless energy transfer rate.
17. The system of claim 11 , wherein κ/√{square root over (Γ 1 Γ 2 )}>0.5 over the range of distances.
18. The system of claim 11 , wherein κ/√{square root over (Γ 1 Γ 2 )}>1 over the range of distances.
19. The system of claim 11 , wherein the source resonant structure and the device resonant structure are configured to be adjustably tuned to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ between the source resonant structure and the device resonant structure over the range of distances.
20. The system of claim 1 , further comprising a power supply coupled to the source resonant structure and an energy drain coupled to the device resonant structure, and wherein the power supply and energy drain are configured to be driven to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ between the source resonant structure and the device resonant structure.
21. A method, comprising:
providing a source resonant structure and a device resonant structure, the structures capable of performing wireless near-field energy transfer with a coupling rate κ when separated a variable distance D from each other,
said source resonant structure having a resonant frequency f 1 =ω 1 /2π, an intrinsic loss rate Γ 1 , and a first Q-factor Q 1 =ω 1 /(2Γ 1 ), where ω 1 is the angular frequency corresponding to the resonant frequency f 1 ,
said device resonant structure having a resonant frequency f 2 =ω 2 /2π, an intrinsic loss rate Γ 2 , and a second Q-factor Q 2 =ω 2 /(2Γ 2 ), where ω 2 is the angular frequency corresponding to the resonant frequency f 2 ,
wherein the absolute value of the difference of said angular frequencies ω 1 and ω 2 is smaller than the magnitude of the coupling rate, κ, and
wherein at least one of the resonant structures comprises a high-Q capacitively-loaded conducting-wire loop.
22. The method of claim 21 , wherein the Q-factor of at least one of the resonant structures is greater than 100.
23. The method of claim 21 , wherein √{square root over (Q 1 Q 2 )}>100.
24. The method of claim 21 , wherein Q 1 >100 and Q 2 >100.
25. The method of claim 21 , wherein a power supply is coupled to the source resonant structure and an energy drain is coupled to the device resonant structure.
26. The method of claim 25 , wherein the energy drain comprises a robot, vehicle, computer, cell phone, or a portable electronic device.
27. The method of claim 21 , wherein a third resonant structure is coupled to an energy drain and located at a variable distance from the source resonant structure, and further comprising wirelessly transferring electromagnetic energy from the source resonant structure to the third resonant structure.
28. The method of claim 21 , wherein a third resonant structure is coupled to a power supply and located at a variable distance from the device resonant structure, and further comprising wirelessly transferring electromagnetic energy from the third resonant structure to the device resonant structure.
29. The method of claim 21 , wherein at least one of the resonant structures is tunable.
30. The method of claim 21 , wherein the resonant structures are movable relative to one another and wherein the wireless energy transfer occurs over a range of distances.
31. The method of claim 30 , wherein the range of distances includes 5 cm.
32. The method of claim 30 , wherein the range of distances includes 10 cm.
33. The method of claim 30 , wherein the range of distances includes 30 cm.
34. The method of claim 30 , wherein the efficiency of the wireless energy transfer is at least 20% over the range of distances.
35. The method of claim 30 , wherein κ/√{square root over (Γ 1 Γ 2 )}>0.2 over the range of distances, wherein κ is the wireless energy transfer rate.
36. The method of claim 30 , wherein κ/√{square root over (Γ 1 Γ 2 )}>0.5 over the range of distances.
37. The method of claim 30 , wherein κ/√{square root over (Γ 1 Γ 2 )}>1 over the range of distances.
38. The method of claim 30 , further comprising correcting at least one of the resonant structures to correct for detuning of the resonant structures over the range of distances.
39. The method of claim 30 , further comprising adjustably tuning at least one of the source and device resonant structures to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ between the source resonant structure and the device resonant structure over the range of distances.
40. The method of claim 21 , wherein a power supply is coupled to the source resonant structure and an energy drain is coupled to the device resonant structure, and wherein the power supply and energy drain are driven to increase the ratio of useful-to-lost power for varying wireless energy transfer rates κ between the source resonant structure and the device resonant structure.