Systems and methods for reduced control inputs in tunable meta-devices

Patent metadata

Field	Value
Publication number	US-10249950-B1
Application number	US-201715706697-A
Country	US
Kind code	B1
Filing date	Sep 16, 2017
Priority date	Sep 16, 2017
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

In some embodiments, an antenna system includes antenna elements for transmitting and/or receiving electromagnetic radiation. The antenna elements may be connected to a feed via a plurality of tunable impedance elements. At least some of the tunable impedance elements may have nonlinear responses to impedance tuning that can be numerically approximated by nonlinear impedance-tuning parameter curves with a cumulative number of selectable nonlinear coefficients. Control inputs to nonlinearly vary impedance values of the tunable impedance elements allow for the selection of distinct impedance patterns that correspond to distinct field patterns attainable by the antenna system. The number of field patterns attainable is a function of the number of control inputs and a cumulative number of selectable nonlinear coefficients. Thus, a selection of tunable impedance elements and control inputs may be made to attain a target number of field patterns to serve a desired coverage area.

First claim

What is claimed is:

1. An antenna system, comprising:
a plurality of antenna elements;
a feed to convey an electromagnetic (EM) signal;
a tunable port network coupling the feed to the plurality of antenna elements, wherein the tunable port network comprises a plurality of tunable impedance elements that each have a nonlinear response to impedance tuning,
wherein the plurality of tunable impedance elements can be numerically approximated by nonlinear impedance-tuning parameter curves with a cumulative number of selectable nonlinear coefficients; and

a plurality of control inputs to nonlinearly vary impedance values of the tunable impedance elements with nonlinear responses to impedance tuning to allow for selection of each of a plurality of distinct impedance patterns of the tunable port network,
wherein each of the plurality of distinct impedance patterns of the tunable port network corresponds to one of a plurality of distinct field patterns attainable by the antenna system, and
wherein the number of distinct field patterns attainable is a function of the number of control inputs and the cumulative number of selectable nonlinear coefficients associated with the plurality of tunable impedance elements.

2. The system of claim 1 , wherein at least some of the cumulative number of selectable nonlinear coefficients are selected from a range of values by selecting an internal structure of at least some of the tunable impedance elements.

3. The system of claim 1 , wherein an impedance of each of the tunable impedance elements is numerically approximated by a nonlinear impedance-tuning curve with at least two unique selectable nonlinear coefficients, such that the cumulative number of selectable nonlinear coefficients is at least twice the number of tunable impedance elements.

4. The system of claim 1 , wherein the number of tunable elements is selected to satisfy the expression

N
p

=

N
tun

×

(

N
tun

2

+

N
NL

)

,

where N p is the number of distinct field patterns, N tun is the number of tunable elements, and N NL is the cumulative number of selectable nonlinear coefficients.

5. The system of claim 1 , wherein the number of tunable elements is selected to be equal to the number of distinct field patterns attainable divided by the cumulative number of selectable nonlinear coefficients, such that N tun =N P /N NL , where N tun is the number of tunable elements, N p is the number of distinct field patterns, and N NL is the cumulative number of selectable nonlinear coefficients.

6. The system of claim 1 , wherein at least one of the tunable impedance elements is tunable via direct current (DC) input and has a nonlinear impedance response to changes in a voltage magnitude of the DC input.

7. The system of claim 1 , wherein at least one of the tunable impedance elements is tunable via an alternating current (AC) input and has a nonlinear impedance response to changes in a voltage magnitude of the AC input.

8. The system of claim 1 , wherein at least one of the tunable impedance elements is tunable via mechanical inputs and has a nonlinear impedance response to changes in a mechanical configuration provided by the mechanical input.

9. The system of claim 1 , wherein some of the tunable impedance elements are tunable via mechanical inputs and have a nonlinear impedance response to changes in a mechanical configuration provided by the mechanical input.

10. The system of claim 1 , wherein the number of control inputs is fewer than the number of tunable impedance elements.

11. The system of claim 10 , wherein at least some of the tunable impedance elements are coupled to a single microstrip control line input.

12. The system of claim 10 , wherein at least some of the tunable impedance elements are patterned on a waveguide as a plurality of resonant elements.

13. The system of claim 1 , wherein the number of control inputs is selected based on a number of distinct field patterns corresponding to a target coverage area of the antenna system scaled by the cumulative number of selectable nonlinear coefficients.

14. The system of claim 1 , wherein each of the tunable impedance elements exhibits mutual coupling with at least two neighboring tunable impedance elements, such that a coordination number, N co , associated with the plurality of tunable impedance elements is at least two.

15. The system of claim 1 , wherein the number of control inputs is less than the number of tunable impedance elements, and wherein at least one of the control inputs affects the impedance tuning of multiple tunable impedance elements.

16. The system of claim 15 , wherein at least one of the control inputs is connected in series to at least two of the tunable impedance elements.

17. The system of claim 15 , wherein at least some of the antenna elements comprise resonant antenna elements.

18. The system of claim 17 , wherein the at least one resonant antenna element and at least one tunable impedance element form a tunable resonant element, and wherein the antenna system comprises a waveguide patterned with tunable resonant elements.

19. The system of claim 17 , wherein the at least one resonant antenna element and at least one tunable impedance element form a tunable resonant element, and wherein the antenna system comprises a multimode resonant cavity patterned with tunable resonant elements.

20. The system of claim 19 , wherein the multimode resonant cavity comprises walls formed from effective impedance metasurface materials with target effective impedance for an operational bandwidth.

21. The system of claim 19 , wherein the multimode resonant cavity is configured with geometric parameter corresponding to a target resonance property.

22. The system of claim 1 , further comprising a control system in communication with the plurality of control inputs to control radiation patterning of the antenna system based on a scattering matrix (S-Matrix) of electromagnetic field amplitudes for each of a plurality of lumped ports, wherein the plurality of lumped ports includes:
a plurality of lumped antenna ports with impedance values corresponding to the impedance values of each of the tunable impedance elements; and
at least one external port located physically external to the antenna device.

23. The system of claim 22 , wherein the control system is configured to control radiation patterning of the antenna system based on the S-Matrix by:
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 external port;
determining an optimized port impedance vector {z n } of impedance values

Assignees

• Searete Llc

Inventors

• Arnitz Daniel
• Hagerty Joseph
• Hannigan Russell J
• Lipworth Guy S
• Reynolds Matthew S
• Urzhumov Yaroslav A

Classifications

• H01Q15/0086

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

• H01Q3/446 Primary

  the radiating element being at the centre of one or more rings of auxiliary elements · CPC title

• H01Q5/22

  RF wavebands combined with non-RF wavebands, e.g. infrared or optical · CPC title

• H01Q25/007

  using two or more primary active elements in the focal region of a focusing device (for operation on different wavebands H01Q5/22) · CPC title

• H01Q21/061

  Two dimensional planar arrays · CPC title