Direct magnetic imaging apparatus and method

• US 20110204891A1
• Filed: 11/24/2010
• Published: 08/25/2011
• Est. Priority Date: 06/25/2009
• Status: Abandoned Application

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Drake, Christina, Baleine, Clara R.
• Application Number:
  US12/926,560
• Publication Number:
  US 20110204891A1
• Time in Patent Office: Days
• US Class Current: 324/309
• CPC Class Codes: G01N 24/084 Detection of potentially hazardous samples, e.g. toxic samples, explosives, drugs, firearms, weapons
• CPC Class Codes: G01R 33/34046 Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/36 Electrical details, e.g. matching or coupling of the coil to the receiver
• 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

Abstract

Methods and apparatuses of the present invention perform imaging using a metamaterial lens structure. The apparatus according to one embodiment comprises: a field source capable of generating an electromagnetic field directed to an area in an object or target; a field detector arranged downstream from the field source, the field detector being capable of detecting a field signature associated with the area in the object or target; and a metamaterial lens structure arranged downstream from the field source, the metamaterial lens structure concentrating the electromagnetic field produced by the field source to the area in the object or target, or concentrating the field signature from the area in the object or target to the field detector.

Claims

1. An imager, said imager comprising:

a field source capable of generating an electromagnetic field directed to an area in an object or target;

a field detector arranged downstream from said field source, said field detector being capable of detecting a field signature associated with said area in said object or target; and

a metamaterial lens structure arranged downstream from said field source, said metamaterial lens structure concentrating said electromagnetic field produced by said field source to said area in said object or target, or concentrating said field signature from said area in said object or target to said field detector.

2. The imager according to claim 1, wherein

said metamaterial lens structure includes one or more metamaterial lenses and/or arrays of metamaterial lenses,

each of said metamaterial lenses includes multiple unit cells, each unit cell including at least one ring with lumped capacitors and/or inductors, and

for each metamaterial lens the magnetic permeability is equal to minus one, or the electric permittivity is equal to minus one, or the refractive index is equal to minus one.

3. The imager according to claim 1, wherein said metamaterial lens structure is an engineered device with a refractive index equal to minus one, or with a magnetic permeability equal to minus one, or with an electric permittivity equal to minus one.

4. The imager according to claim 1, wherein said electromagnetic field is a magnetic field and said field detector is a magnetic field detector.

5. The imager according to claim 1, wherein said electromagnetic field is an electric field and said field detector detects electric fields.

6. The imager according to claim 1, wherein said metamaterial lens structure is refocused in one or more dimensions.

7. The imager according to claim 1, wherein said imager performs direct magnetic imaging by which a magnetic field is focused by said metamaterial lens structure into said object/target and/or into said field detector, by refocusing said metamaterial lens structure in one or more dimensions.

8. The imager according to claim 1, wherein said electromagnetic field includes an RF signal, and said metamaterial lens structure performs focusing of said RF signal by encoding said RF signal in multiple spatial dimensions.

9. The imager according to claim 1, wherein said electromagnetic field is an AC magnetic field at a frequency characteristic to said object/target, and said metamaterial lens structure focuses said AC magnetic field into said object/target and also focuses said field signature to said field detector.

10. The imager according to claim 1, wherein said electromagnetic field is an AC magnetic field at a frequency characteristic to the object or target and said metamaterial lens structure focuses said AC magnetic field into said object/target, and

said imager further comprises a second metamaterial lens structure which focuses said field signature to said field detector.

11. The imager according to claim 1, wherein said imager is an MRI imager comprising gradient coils, said field detector is an RF receiver, and said metamaterial lens structure concentrates an RF field to an anatomical area of said object and/or concentrates a magnetic field signature from said anatomical area to said RF receiver.

12. The imager according to claim 1, wherein said field detector is a tunable magnetometer, and said metamaterial lens structure is tuned to one or more collecting frequencies of said magnetometer while concentrating a magnetic field signature into said field detector.

13. The imager according to claim 1, wherein said metamaterial lens structure concentrates said field signature from said area in said object/target to said field detector, and said metamaterial lens is tuned to specific frequencies in conjunction with frequencies detected by said field detector.

14. The imager according to claim 1, wherein said imager is an MRI or an NMR imager which has been modified to include said metamaterial lens structure.

15. The imager according to claim 1, wherein said field detector detects said field signature using one or more of a super quantum interference detector, a magnetometer detector, an antenna, an RF coil, and a MEMS device.

16. An imaging method, said method comprising:

generating an electromagnetic field directed to an area in an object or target;

detecting a field signature associated with said area in said object or target; and

concentrating, using a metamaterial lens structure, said electromagnetic field to said area in said object or target, and/or concentrating said field signature from said area in said object or target before said detecting step.

17. The method according to claim 16, wherein

said concentrating step is performed by one or more metamaterial lenses having a magnetic permeability equal to minus one, or an electric permittivity equal to minus one, or a refractive index equal to minus one, and

each of said metamaterial lenses includes multiple unit cells, each unit cell including at least one ring with lumped capacitors and/or inductors.

18. The method according to claim 16, wherein said concentrating step is performed by one or more metamaterial lenses with a refractive index equal to minus one, or with a magnetic permeability equal to minus one, or with an electric permittivity equal to minus one.

19. The method according to claim 16, wherein said electromagnetic field is a magnetic field.

20. The method according to claim 16, wherein said electromagnetic field is an electric field.

21. The method according to claim 16, said concentrating step comprising refocusing said metamaterial lens structure in one or more dimensions.

22. The method according to claim 16, wherein said method performs direct magnetic imaging by which a magnetic field is focused by said metamaterial lens structure into said object/target and/or into said field detector, by refocusing said metamaterial lens structure in one or more dimensions.

23. The method according to claim 16, wherein said electromagnetic field is an RF signal, and said concentrating step comprises focusing said RF signal by said metamaterial lens structure, by encoding said RF signal in multiple spatial dimensions.

24. The method according to claim 16, wherein

said electromagnetic field is an AC magnetic field at a frequency characteristic to said object/target, and

said concentrating step comprises

focusing said AC magnetic field by said metamaterial lens structure into said object/target, and

focusing said field signature from said object/target, by said metamaterial lens structure, before said detecting step.

25. The method according to claim 16, wherein

said electromagnetic field is an AC magnetic field at a frequency characteristic to said object or target, and

said concentrating step comprises

focusing said AC magnetic field by said metamaterial lens structure into said object/target, and

focusing said field signature from said object/target, by a second metamaterial lens structure, before said detecting step.

26. The method according to claim 16, wherein said method is a method for magnetic resonance imaging, and

said concentrating step

concentrates an RF field by said metamaterial lens structure to an anatomical area, and

concentrates a magnetic field signature from said anatomical area to an RF receiver by another metamaterial lens structure.

27. The method according to claim 16, further comprising:

tuning said metamaterial lens structure to one or more detecting frequencies used in said detecting step, while concentrating said field signature which is a magnetic field signature.

28. The method according to claim 16, wherein said method is a method for nuclear magnetic imaging.

29. The method according to claim 16, wherein said concentrating step and said detecting step comprise tuning at one or more detecting frequencies.

30. A metamaterial lens, said lens comprising:

multiple unit cells, each unit cell including at least one ring with lumped capacitors and/or inductors.

31. The metamaterial lens according to claim 30, wherein each of said unit cells is a parallelepiped including said capacitors and inductors along a plurality of sides of said parallelepiped.

32. The metamaterial lens according to claim 30, wherein said lens is an isotropic lens in which said unit cells are arranged in an array.

33. The metamaterial lens according to claim 30, wherein rings in said unit cells include only lumped capacitors.

34. The metamaterial lens according to claim 30, wherein said at least one ring includes

capacitors, and

meander line inductors.

35. The metamaterial lens according to claim 30, wherein each of said unit cells includes at least one split ring with lumped capacitors and inductors.

36. The metamaterial lens according to claim 35, wherein said at least one split ring is a split ring resonator element including a metal strip and a gap, wherein said split ring acts as the unit cell and said gap is filled with a capacitor or inductor.

37. The metamaterial lens according to claim 30, wherein said lens includes a magnetic material.

38. The metamaterial lens according to claim 30, wherein said lens includes a magnetic material in inductors in said unit cells.