Surface scattering antennas

• US 20120194399A1
• Filed: 10/14/2011
• Published: 08/02/2012
• Est. Priority Date: 10/15/2010
• Status: Active Grant

• Current Assignee: The Invention Science Fund I, L.L.C. (Intellectual Ventures LLC)
• Original Assignee: The Invention Science Fund I, L.L.C. (Intellectual Ventures LLC)
• Inventors: Hannigan, Russell J., Kundtz, Nathan, Nash, David R., Bily, Adam, Boardman, Anna K., Hunt, John, Stevenson, Ryan Allan, Sullivan, Philip A.
• Granted Patent: US 9,450,310 B2
• Time in Patent Office: Days
• US Class Current: 343/772
• CPC Class Codes: H01Q 13/28 comprising elements constituting electric discontinuities and spaced in direction of wave propagation, e.g. dielectric elements or conductive elements forming artificial dielectric
• CPC Class Codes: H01Q 15/0006 Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices H01Q15/12, H01Q15/22, H01Q15/24 take precedence
• CPC Class Codes: H01Q 15/0066 said selective devices being reconfigurable, tunable or controllable, e.g. using switches
• CPC Class Codes: H01Q 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism
• CPC Class Codes: H01Q 15/10 comprising three-dimensional array of impedance discontinuities, e.g. holes in conductive surfaces or conductive discs forming artificial dielectric
• CPC Class Codes: H01Q 3/00 Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system means for positioning H01Q1/125

Abstract

Surface scattering antennas provide adjustable radiation fields by adjustably coupling scattering elements along a wave-propagating structure. In some approaches, the scattering elements are complementary metamaterial elements. In some approaches, the scattering elements are made adjustable by disposing an electrically adjustable material, such as a liquid crystal, in proximity to the scattering elements. Methods and systems provide control and adjustment of surface scattering antennas for various applications.

Claims

1. An antenna, comprising:

a wave-propagating structure; and

a plurality of scattering elements distributed along the wave-propagating structure with inter-element spacings substantially less than a free-space wavelength corresponding to an operating frequency of the antenna, where the plurality of scattering elements have a plurality of adjustable individual electromagnetic responses to a guided wave or surface wave mode of the wave-propagating structure, and the plurality of adjustable individual electromagnetic responses provide an adjustable radiation field of the antenna.

2. The antenna of claim 1, wherein the plurality of scattering elements is a plurality of substantially identical scattering elements.

3. The antenna of claim 1, wherein the plurality of adjustable individual electromagnetic responses provides an effective medium response for the guided wave or surface wave mode of the wave-propagating structure.

4. The antenna of claim 1, wherein the plurality of adjustable individual electromagnetic responses is a plurality of magnetic dipole radiation fields.

5. The antenna of claim 1, wherein the operating frequency is a microwave frequency.

6. The antenna of claim 5, wherein the microwave frequency is a Ka band frequency.

7. The antenna of claim 5, wherein the microwave frequency is a Ku band frequency.

8. The antenna of claim 5, wherein the microwave frequency is a Q band frequency.

9. The system of claim 1, wherein the inter-element spacing is less than one-fourth of the free space wavelength.

10. The system of claim 1, wherein the inter-element spacing is less than one-fifth of the free space wavelength.

11. The antenna of claim 1, wherein the wave-propagating structure includes one or more conducting surfaces and the plurality of scattering elements corresponds to a plurality of apertures within the one or more conducting surfaces.

12. The antenna of claim 11, wherein the wave-propagating structure is a substantially two-dimensional wave-propagating structure.

13. The antenna of claim 12, wherein the substantially two-dimensional wave-propagating structure is a parallel plate waveguide, and the one or more conducting surfaces are an upper conductor of the parallel plate waveguide.

14. The antenna of claim 11, wherein the wave-propagating structure includes one or more substantially one-dimensional wave-propagating structures.

15. The antenna of claim 14, wherein the one or more substantially one-dimensional wave-propagating structures are a plurality of substantially one-dimensional wave-propagating structures composing a substantially two-dimensional antenna area.

16. The antenna of claim 14, wherein the one or more substantially one-dimensional wave-propagating structures include one or more microstrips.

17. The antenna of claim 16, wherein the one or more conducting surfaces are one or more respective upper conductors of the one or more micro strips.

18. The antenna of claim 16, wherein the one or more conducting surfaces are one or more conducting strips positioned parallel to one or more upper conductors of the one or more microstrips.

19. The antenna of claim 14, wherein the one or more substantially one-dimensional wave-propagating structures include one or more coplanar waveguides.

20. The antenna of claim 19, wherein the one or more conducting surfaces are positioned above the one or more coplanar waveguides.

21. The antenna of claim 14, wherein the one or more substantially one-dimensional wave-propagating structures include one or more closed waveguides.

22. The antenna of claim 21, wherein the one or more closed waveguides include one or more rectangular waveguides.

23. The antenna of claim 22, wherein the one or more rectangular waveguides includes one or more double-ridged rectangular waveguides.

24. The antenna of claim 21, wherein the one or more conducting surfaces are one or more respective upper surfaces of the one or more closed waveguides.

25. The antenna of claim 21, wherein the one or more conducting surfaces are positioned above one or more respective upper surfaces of the one or more closed waveguides, and the one or more respective upper surfaces include a plurality of irises adjacent to the plurality of apertures within the one or more conducting surfaces

26. The antenna of claim 11, wherein the plurality of apertures defines a respective plurality of conducting islands that are electrically disconnected from the one or more conducting surfaces, and the antenna further comprises:

a plurality of bias voltage lines configured to provide respective bias voltages between the one or more conducting surfaces and the respective plurality of conducting islands; and

an electrically adjustable material disposed at least partially within respective vicinities of the plurality of apertures.

27. The antenna of claim 26, wherein the electrically adjustable material is a liquid crystal material.

28. The antenna of claim 27, wherein the liquid crystal material is a nematic liquid crystal.

29. The antenna of claim 27, wherein the liquid crystal material is a dual-frequency liquid crystal.

30. The antenna of claim 27, wherein the liquid crystal material is a polymer network liquid crystal.

31. The antenna of claim 27, wherein the liquid crystal material is a polymer dispersed liquid crystal.

32. The antenna of claim 11, wherein the plurality of apertures defines a respective plurality of conducting islands that are electrically disconnected from the one or more conducting surfaces, the plurality of apertures are arranged in rows and columns, and the antenna further comprises:

a plurality of biasing circuits configured to provide respective bias voltages between the one or more conducting surfaces and the respective plurality of conducting islands;

a set of row control lines each addressing a row of the plurality of biasing circuits;

a set of column control lines each addressing a column of the plurality of biasing circuits; and

an electrically adjustable material disposed at least partially within respective vicinities of the plurality of apertures.

33. The antenna of claim 32, wherein the plurality of biasing circuits are arranged in rows and columns respectively adjacent to the plurality of apertures.

34. The antenna of claim 11, wherein the plurality of apertures defines a plurality of complementary metamaterial elements having a plurality of magnetic dipole responses to a magnetic field of the guided wave or surface wave.

35. The antenna of claim 34, wherein the plurality of complementary metamaterial elements is a plurality of complementary electric LC metamaterial elements.

36. The antenna of claim 34, wherein the plurality of magnetic dipole responses is a plurality of in-plane magnetic dipole responses oriented parallel to the one or more conducting surfaces.

37. The antenna of claim 36, wherein the plurality of in-plane magnetic dipole responses includes a first plurality of in-plane magnetic dipole responses oriented in a first direction parallel to the one or more conducting surfaces and a second plurality of in-plane magnetic dipole responses oriented in a second direction perpendicular to the first direction and parallel to the one or more conducting surfaces

38. A method, comprising:

propagating a first guided wave or surface wave to deliver a first plurality of relative phases to a respective plurality of locations;

coupling to the first guided wave or surface wave at a first set of locations selected from the respective plurality of locations to produce a first plurality of electromagnetic oscillations at the first set of locations, the first plurality of electromagnetic oscillations producing a first radiation field;

propagating a second guided wave or surface wave to deliver a second plurality of relative phases to the respective plurality of locations, where the second plurality of relative phases is substantially equal to the first plurality of relative phases; and

coupling to the second guided wave or surface wave at a second set of locations selected from the respective plurality of locations to produce a second plurality of electromagnetic oscillations at the second set of locations, the second plurality of electromagnetic oscillations producing a second radiation field different from the first radiation field.

39. The method of claim 38, wherein:

the first guided wave or surface wave and the first radiation field define a first interference pattern, and the first set of locations selected from the respective plurality of locations corresponds to a set of locations within constructive interference regions of the first interference pattern; and

the second guided wave or surface wave and the second radiation field define a second interference pattern different from the first interference pattern, and the second set of locations selected from the respective plurality of locations corresponds to a set of locations within constructive interference regions of the second interference pattern.

40. A method, comprising:

receiving a first free-space wave at a plurality of locations;

coupling to the first free-space wave at a first set of locations selected from the plurality of locations to produce a first plurality of electromagnetic oscillations at the first set of locations, the first plurality of electromagnetic oscillations producing a first guided wave or surface wave having a first plurality of relative phases at the plurality of locations;

receiving a second free-space wave different from the first free-space wave at the plurality of locations;

coupling to the second free-space wave at a second set of locations selected from the plurality of locations to produce a second plurality of electromagnetic oscillations at the second set of locations, the second plurality of electromagnetic oscillations producing a second guided wave or surface wave having a second plurality of relative phases at the plurality of locations, where the second plurality of relative phases is substantially equal to the first plurality of relative phases.

41. The method of claim 40, wherein:

the first guided wave or surface wave and the first free-space wave define a first interference pattern, and the first set of locations selected from the respective plurality of locations corresponds to a set of locations within constructive interference regions of the first interference pattern; and

the second guided wave or surface wave and the second free-space wave define a second interference pattern different from the first interference pattern, and the second set of locations selected from the respective plurality of locations corresponds to a set of locations within constructive interference regions of the second interference pattern.

42-103. -103. (canceled)