Cavity-backed artificial magnetic conductor

• US 9,705,201 B2
• Filed: 02/20/2015
• Issued: 07/11/2017
• Est. Priority Date: 02/24/2014
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Gregoire, Daniel J., White, Carson R.
• Primary Examiner(s): Levi, Dameon E
• Assistant Examiner(s): Hu, Jennifer F
• Application Number:
  US14/628,076
• Publication Number:
  US 20150263432A1
• Time in Patent Office: 872 Days
• Field of Search: 343913
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
• CPC Class Codes: H01Q 15/002 said selective devices being reconfigurable or tunable, e.g. using switches or diodes
• CPC Class Codes: H01Q 15/0066 said selective devices being reconfigurable, tunable or controllable, e.g. using switches
• CPC Class Codes: H01Q 15/008 said selective devices having Sievenpipers' mushroom elements
• CPC Class Codes: H01Q 15/142 using insulating material for supporting the reflecting surface
• CPC Class Codes: H01Q 15/148 with means for varying the reflecting properties H01Q15/147 takes precedence
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2203/08 Treatments involving gases
• CPC Class Codes: H05K 2203/162 Testing a finished product, e.g. heat cycle testing of solder joints patterns for electrical inspection or testing H05K1/0268

Abstract

An active artificial magnetic conductor includes an array of unit cells, each unit cell including a top face, at least one wall coupled to the top face, a base coupled to the at least one wall, and a crossed slot in the top face. The top face, the at least one wall, and the base form a cavity and are conductive.

Claims

1. An active artificial magnetic conductor (AAMC) comprising:

an array of unit cells, each unit cell comprising;

a top face;

at least one wall coupled to the top face;

a base coupled to the at least one wall; and

a crossed slot in the top face, wherein the crossed slot extends to the at least one wall dividing the top face into four patches;

wherein the at least one wall is a continuous wall between the top face and the base;

wherein the top face, the at least one wall, and the base form a cavity inside the top face, the at least one wall, and the base; and

wherein the four patches, the at least one wall, and the base are conductive.

2. The AAMC of claim 1 wherein:

the top face has first, second, third and fourth edges; and

the at least one wall comprises;

a first wall coupled to the first edge of the top face;

a second wall coupled to the second edge of the top face;

a third wall coupled to the third edge of the top face; and

a fourth wall coupled to the fourth edge of the top face.

3. The AAMC of claim 2 wherein the crossed slot extends to each of the first, second, third and fourth edges of the top face.

4. The AAMC of claim 1 further comprising:

a material filling the cavity, the material comprising air, a dielectric material, or a magnetic material.

5. The AAMC of claim 1 wherein:

each unit cell is symmetric about an x-z and about a y-z axis; and

the top face is planar.

6. The AAMC of claim 2 wherein:

the cavity has a square cross section of size slightly less than a period of repetition of the unit cells in the array of unit cells.

7. The AAMC of claim 1 further comprising:

at least one reactive tuning element coupled across the crossed slot.

8. The AAMC of claim 7 wherein the at least one reactive tuning element comprises a Non-Foster circuit.

9. The AAMC of claim 8 wherein the Non-Foster circuit comprises a negative inductance or a negative capacitance.

10. The AAMC of claim 1 wherein the cavity and the crossed slot provide a dual-polarized response.

11. The AAMC of claim 2 further comprising:

at least two reactive tuning elements coupled across the crossed slot.

12. The AAMC of claim 11 wherein:

the crossed slot divides the top face into first, second, third, and fourth patches; and

the at least two reactive elements comprise;

a first reactive element connected across the crossed slot between the first patch and the second patch;

a second reactive element connected across the crossed slot between the third patch and the fourth patch;

a third reactive element connected across the crossed slot between the first patch and the third patch; and

a fourth reactive element connected across the crossed slot between the second patch and the fourth patch;

wherein the first and second reactive elements are across the crossed slot in an X axis; and

wherein the third and fourth reactive elements are across the crossed slot in a y axis.

13. The AAMC of claim 12 wherein the first, second, third and fourth reactive tuning elements are Non-Foster circuits.

14. The AAMC of claim 13 wherein each Non-Foster circuit comprises a negative inductance or a negative capacitance.

15. The AAMC of claim 11 wherein:

the crossed slot divides the top face into a first, second, third, and fourth patches, each patch having a corner near a junction of the crossed slot; and

the at least two reactive elements comprise;

a first terminal of a first reactive element connected near the corner of the first patch;

a first terminal of a second reactive element connected near the corner of the second patch;

a first terminal of a third reactive element connected near the corner of the third patch; and

a first terminal of a fourth reactive element connected near the corner of the fourth patch; and

wherein a second terminal of each of the first, second, third and fourth reactive elements are connected together.

16. The AAMC of claim 15 wherein the first, second, third and fourth reactive tuning elements are Non-Foster circuits.

17. The AAMC of claim 16 wherein each Non-Foster circuit comprises a negative inductance or a negative capacitance.

18. The AAMC of claim 11 wherein:

the crossed slot divides the top face into a first, second, third, and fourth patches, each patch having a corner near a junction of the crossed slot; and

the at least two reactive elements comprise;

a first terminal of a first reactive element connected near the corner of the first patch;

a second terminal of the first reactive element connected near the corner of the fourth patch;

a first terminal of a second reactive element connected near the corner of the second patch;

a second terminal of the second reactive element connected near the corner of the third patch;

wherein the corner of the first patch is diagonally across the junction of the crossed slot from the corner of the fourth patch; and

wherein the corner of the second patch is diagonally across the junction of the crossed slot from the corner of the third patch.

19. The AAMC of claim 18 wherein the first and second reactive tuning elements are Non-Foster circuits.

20. The AAMC of claim 19 wherein each Non-Foster circuit comprises a negative inductance or a negative capacitance.

21. An active artificial magnetic conductor (AAMC) comprising:

an array of unit cells, each unit cell comprising;

a square top face having first, second, third and fourth edges;

a first wall coupled to the first edge of the top face;

a second wall coupled to the second edge of the top face;

a third wall coupled to the third edge of the top face;

a fourth wall coupled to the fourth edge of the top face;

a base coupled to the first, second, third and fourth walls; and

a crossed slot in the top face, the crossed slot extending to each of the four edges of the top face dividing the top face into four patches;

wherein the first wall, the second wall, the third wall and the fourth wall are each a continuous wall between the top face and the base;

wherein the top face, the first, second, third and fourth walls, and the base form a cavity inside the top face, the first, second, third and fourth walls; and

wherein the four patches, the first, second, third and fourth walls, and the base are conductive.

22. The AAMC of claim 21 further comprising:

a material filling the cavity, the material comprising air, a dielectric material, or a magnetic material.

23. The AAMC of claim 21:

wherein the crossed slot divides the top face into first, second, third, and fourth patches; and

wherein the AAMC further comprises;

a first reactive element connected across the crossed slot between the first patch and the second patch;

a second reactive element connected across the crossed slot between the third patch and the fourth patch;

a third reactive element connected across the crossed slot between the first patch and the third patch; and

a fourth reactive element connected across the crossed slot between the second patch and the fourth patch;

wherein the first and second reactive elements are across the crossed slot in an X axis; and

wherein the third and fourth reactive elements are across the crossed slot in a y axis.

24. The AAMC of claim 21:

wherein the crossed slot divides the top face into a first, second, third, and fourth patches, each patch having a corner near a junction of the crossed slot; and

the AAMC further comprises;

a first terminal of a first reactive element connected near the corner of the first patch;

a first terminal of a second reactive element connected near the corner of the second patch;

a first terminal of a third reactive element connected near the corner of the third patch; and

a first terminal of a fourth reactive element connected near the corner of the fourth patch; and

wherein a second terminal of each of the first, second, third and fourth reactive elements are connected together.

25. The AAMC of claim 21:

wherein the crossed slot divides the top face into a first, second, third, and fourth patches, each patch having a corner near a junction of the crossed slot; and

the AAMC further comprises;

a first terminal of a first reactive element connected near the corner of the first patch;

a second terminal of the first reactive element connected near the corner of the fourth patch;

a first terminal of a second reactive element connected near the corner of the second patch;

a second terminal of the second reactive element connected near the corner of the third patch;

wherein the corner of the first patch is diagonally across a junction of the crossed slot from the corner of the fourth patch; and

wherein the corner of the second patch is diagonally across a junction of the crossed slot from the corner of the third patch.

26. The AAMC of claim 21 wherein:

each unit cell is symmetric about an x-z and about a y-z axis; and

the top face is planar.

27. The AAMC of claim 21 wherein:

the cavity has a square cross section of size slightly less than a period of repetition of the unit cells in the array of unit cells.