Low index metamaterial

• US 8,466,370 B2
• Filed: 09/22/2009
• Issued: 06/18/2013
• Est. Priority Date: 09/30/2008
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Lier, Erik
• Primary Examiner(s): Norris, Jeremy
• Assistant Examiner(s): Willis, Tremesha S
• Application Number:
  US12/564,847
• Publication Number:
  US 20100078203A1
• Time in Patent Office: 1,365 Days
• Field of Search: 174/258, 343772-773, 343/783, 343785-787
• US Class Current: 174/258
• CPC Class Codes: H01Q 13/02 Waveguide horns
• CPC Class Codes: H01Q 13/0275 Ridged horns slot-line radiating ends H01Q13/085
• CPC Class Codes: H01Q 15/0073 said selective devices having corrugations
• CPC Class Codes: H01Q 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials

Abstract

Various aspects of the disclosure provide low index metamaterials. The low index metamaterials may be used to form soft and/or hard electromagnetic (EM) boundaries to facilitate desired EM performance or propagation in applications including feed horns, spatial feed/combiners, isolation barriers between antennas or RF modules, and reduced radar cross-section applications. In one aspect, a low index metamaterial comprises a dielectric layer and a plurality of conductors on a surface of the dielectric layer, embedded in the dielectric layer or both, wherein the low index metamaterial appears as a medium having a dielectric constant less than one with respect to electromagnetic waves at predetermined frequencies and propagating at grazing angles with respect to a surface of the low index metamaterial.

Claims

1. A low index metamaterial, comprising:

a dielectric layer; and

a plurality of conductors on a surface of the dielectric layer, embedded in the dielectric layer or both, so as to form the low index metamaterial;

wherein the low index metamaterial appears as a medium having a dielectric constant greater than zero and less than one with respect to electromagnetic waves at predetermined frequencies, the electromagnetic waves propagating at grazing angles with respect to a surface of the low index metamaterial.

2. The low index metamaterial of claim 1, wherein the plurality of conductors comprises a plurality of vias embedded in the dielectric layer.

3. The low index metamaterial of claim 2, wherein the plurality of conductors comprises a plurality of strips on the surface of the dielectric layer.

4. The low index metamaterial of claim 2, wherein the plurality of conductors comprises a plurality of strips embedded in the dielectric layer.

5. The low index metamaterial of claim 4, wherein the plurality of strips are orientated parallel to the surface of the dielectric layer.

6. The low index metamaterial of claim 1, wherein the plurality of conductors comprises a plurality of strips on the surface of the dielectric layer.

7. The low index metamaterial of claim 1, wherein the plurality of conductors comprises a plurality of strips embedded in the dielectric layer.

8. The low index metamaterial of claim 7, wherein the plurality of strips are orientated parallel to the surface of the dielectric layer.

9. The low index metamaterial of claim 1, wherein the dielectric constant of the low index metamaterial varies along one or more directions.

10. A hard boundary liner, comprising:

a low index metamaterial, the low index metamaterial comprising;

a first dielectric layer; and

a plurality of conductors on a surface of the dielectric layer, embedded in the first dielectric layer or both;

wherein the low index metamaterial appears as a medium having a dielectric constant greater than zero and less than one with respect to electromagnetic waves at predetermined frequencies, the electromagnetic waves propagating at grazing angles with respect to a surface of the low index metamaterial; and

a second dielectric layer overlaying the low index metamaterial.

11. The hard boundary liner of claim 10, wherein the plurality of conductors comprises a plurality of vias embedded in the first dielectric layer.

12. The hard boundary liner of claim 11, wherein the plurality of conductors comprises a plurality of strips orientated parallel to the surface of the first dielectric layer.

13. The hard boundary liner of claim 10, wherein the plurality of conductors comprises a plurality of strips orientated parallel to the surface of the first dielectric layer.

14. The hard boundary liner of claim 10, wherein the second dielectric layer comprises a second metamaterial.

15. The hard boundary liner of claim 10, wherein the dielectric constant of the low index metamaterial varies alone one or more directions.

16. A low index metamaterial, comprising:

a plurality of interconnected wires forming a free-standing three-dimensional grid structure so as to form the low index metamaterial;

wherein the low index metamaterial appears as a medium having a dielectric constant greater than zero and less than one with respect to electromagnetic waves at predetermined frequencies, the electromagnetic waves propagating at grazing angles with respect to a surface of the low index metamaterial.

17. The low index metamaterial of claim 16, wherein the plurality of wires includes wires orientated along two orthogonal directions.

18. The low index metamaterial of claim 16, wherein the plurality of wires includes wires orientated along three orthogonal directions.

19. The low index metamaterial of claim 16, wherein the dielectric constant of the low index metamaterial varies along one or more directions.