Wireless power transfer using tunable metamaterial systems and methods

Patent metadata

Field	Value
Publication number	US-10063101-B2
Application number	US-201514986255-A
Country	US
Kind code	B2
Filing date	Dec 31, 2015
Priority date	Sep 4, 2015
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

The present disclosure provides system and methods for optimizing the tuning of impedance elements associate with sub-wavelength antenna elements to attain target radiation and/or field patterns. A scattering matrix (S-Matrix) of field amplitudes for each of a plurality of modeled lumped ports, N, may be determined that includes a plurality of lumped antenna ports, N a , with impedance values corresponding to the impedance values of associated impedance elements and at least one modeled external port, N e , located external to the antenna system at a specified radius vector. Impedance values may be identified through an optimization process, and the impedance elements may be tuned (dynamically or statically) to attain a specific target radiation pattern.

First claim

What is claimed is:

1. A wireless power transmitter, comprising:
a plurality of sub-wavelength antenna elements configured to scatter received electromagnetic fields;
a plurality of lumped impedance elements in communication with the plurality of sub-wavelength antenna elements;
a plurality of variable impedance control inputs configured to allow for the selection of an impedance value for each of the lumped impedance elements;
a computer-readable medium providing instructions accessible to a processor to cause the processor to perform operations for radiation patterning, comprising:
determining a scattering matrix (S-Matrix) of electromagnetic field amplitudes for each of a plurality of lumped ports, wherein the lumped ports include:
a plurality of lumped antenna ports with impedance values corresponding to the impedance values of each of the plurality of lumped impedance elements; and
at least one lumped external port corresponding to a wireless power receiver located physically external to the wireless power transmitter,
wherein the S-Matrix is expressible in terms of an impedance matrix, Z-Matrix, with impedance values of each of the plurality of lumped ports;

identifying a target electromagnetic radiation pattern of the wireless power transmitter defined in terms of target electromagnetic field amplitudes in the S-Matrix for the at least one lumped external port;
determining an optimized port impedance vector {z n } of impedance values for each of the lumped antenna ports that results in an S-Matrix element for the at least one lumped external port that approximates the target electromagnetic field amplitude for an operating frequency; and
adjusting at least one of the plurality of variable impedance control inputs to modify at least one of the impedance values of at least one of the plurality of variable lumped impedance elements based on the determined optimized {z n } of the impedance values for the lumped antenna ports.

2. The transmitter of claim 1 , wherein the plurality of sub-wavelength antenna elements is divided into at least two groups,
wherein sub-wavelength antenna elements within each group are separated from one another by no more than half of an operating wavelength, and
wherein each group of sub-wavelength antenna elements is spatially separated from each other group of sub-wavelength antenna elements by at least a distance exceeding that of half of an operating wavelength.

3. The transmitter of claim 2 , wherein the at least two groups of sub-wavelength antenna elements comprises a first group of sub-wavelength antenna elements that is not co-planar with a second group of sub-wavelength antenna elements.

4. The transmitter of claim 3 , wherein the target electromagnetic radiation pattern is selected to optimize a power transfer from the first group of sub-wavelength antenna elements to the second group of sub-wavelength antenna elements.

5. The transmitter of claim 4 , wherein optimizing the power transfer comprises maintaining the power transferred to another lumped external port below a threshold level.

6. The transmitter of claim 5 , wherein maintaining below the threshold level is a maintaining below a predetermined threshold to avoid overexposing objects, equipment, or living things.

7. The transmitter of claim 5 , wherein maintaining below the threshold is a specific limiting of power density within a dynamic exclusion zone.

8. The transmitter of claim 1 , wherein the impedance control input associated with at least one of the lumped impedance elements comprises a direct current (DC) voltage input, wherein the impedance value of the at least one lumped impedance element is based on the magnitude of the voltage supplied via the DC voltage input.

9. The transmitter of claim 1 , wherein the impedance control input associated with at least one of the lumped impedance elements can be varied to adjust the impedance value of the at least one lumped impedance element, wherein the impedance control input comprises one of: an electrical current input, a radiofrequency electromagnetic wave input, an optical radiation input, a thermal radiation input, a terahertz radiation input, an acoustic wave input, a phonon wave input, a thermal conduction input, a mechanical pressure input and a mechanical contact input.

10. The transmitter of claim 1 , wherein each of the lumped impedance elements is modeled as an encapsulated two-port structure connected to the terminals of a lumped port.

11. The transmitter of claim 1 , wherein at least one of the lumped impedance elements comprises at least one of a split ring resonator, an ELC resonator, a spiral resonator, a complementary split ring resonator, and a complementary ELC resonator.

12. The transmitter of claim 1 , wherein at least one of the lumped impedance elements is connected to and collocated with a tunable microelectronic circuit.

13. The transmitter of claim 1 , wherein at least some of the lumped impedance elements are connected to and collocated with tunable microelectronic circuits addressable using a row and column addressing scheme.

14. The transmitter of claim 1 , wherein at least one of the lumped impedance elements is connected to and collocated with a tunable microelectronic circuit located at the intersection of a word line and a bit line, and connected to both the word line and the bit line.

15. The transmitter of claim 1 , wherein the lumped impedance elements form a concentric-circular array with elements aligned along radial lines from a common center.

16. The transmitter of claim 1 , wherein the at least one lumped external port comprises a plurality of lumped external ports all located external to the wireless power transmitter, and wherein the target electromagnetic field amplitudes in the S-Matrix of each of the plurality of lumped external ports correspond to a target electromagnetic radiation pattern of the wireless power transmitter for at least the operating frequency.

17. The transmitter of claim 16 , wherein each of the sub-wavelength antenna elements comprises an antenna element with a maximum dimension that is less than half of a wavelength of the smallest frequency in an operating frequency range.

18. The transmitter of claim 16 , wherein the at least one lumped external port comprises a virtual external port.

19. The transmitter of claim 16 , wherein the at least one lumped external port comprises a receiving antenna associated with the wireless power receiver.

20. The transmitter of claim 1 , wherein determining the optimized {z n } comprises calculating the optimized {z n } by optimizing the values of impedance control inputs that are related to the impedance values for each of the lumped antenna ports through at least one nonlinear function.

21. The transmitter of claim 1 , wherein identifying the target electromagnetic radiation pattern of the wireless power transmitter in terms of the target electromagnetic field amplitude in the S-Matrix for the at least one lumped external port comprises:
identifying the target electromagnetic radiation pattern of the wireless power transmitter in terms of a target field amplitude for a single linear field polarization.

22. The transmitter of claim 1 , wherein the at least one lumped external port comprises a plurality of lumped external ports all located external to the wireless power transmitter, and
wherein identifying the target electromagnetic radiation pattern of the wireless power transmitter in terms of the target field amplitud

Assignees

• Elwha Llc

Inventors

• Black Eric J
• Deutsch Brian Mark
• Katko Alexander Remley
• Machado Melroy
• Mccandless Jay Howard
• Urzhumov Yaroslav A

Classifications

• H01Q15/0086 Primary

  said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials · CPC title

• H02J50/12 Primary

  of the resonant type · CPC title

• H02J50/90

  involving detection or optimisation of position, e.g. alignment · CPC title

• H01Q3/36

  with variable phase-shifters · CPC title

• H02J50/60

  responsive to the presence of foreign objects, e.g. detection of living beings · CPC title