Frequency selective surface and method of manufacture

• US 6,995,733 B2
• Filed: 12/24/2002
• Issued: 02/07/2006
• Est. Priority Date: 12/24/2002
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Waltho, Alan E.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US10/328,479
• Publication Number:
  US 20040119658A1
• Time in Patent Office: 1,141 Days
• Field of Search: 343/909, 343/700.MS, 343/846, 343/895, 343/756
• US Class Current: 343/909
• CPC Class Codes: H01Q 1/243 with built-in antennas
• 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 19/021 Means for reducing undesirable effects

Abstract

Briefly, in accordance with an embodiment of the invention, a frequency selective surface (FSS) structure and a method is provided. The FSS structure may include a first conductive plate over a first surface of a substrate. The FSS structure may further include a first printed inductor over the first surface of the substrate and coupled to the first conductive plate. The method may include forming a frequency selective surface by patterning a first conductive material over a surface of a substrate to form a printed inductor.

Claims

1. An apparatus, comprising:

a frequency selective surface (FSS) structure that includes;

a first conductive plate over a first surface of a substrate; and

a first printed inductor over the first surface of the substrate and coupled to the first conductive plate;

a ground plane over a second surface of the substrate;

a first conductive via in the substrate and coupled to the ground plane and the first printed inductor; and

a second printed inductor over the second surface of the substrate.

2. The apparatus of claim 1, wherein the ground plane, the first conductive plate, the first printed inductor, the second printed inductor, and the first conductive via form a resonant circuit.

3. The apparatus of claim 2, wherein the first conductive via is serially coupled to the printed inductor to form an inductive element.

4. The apparatus of claim 2, wherein the first conductive plate and the ground plane form a capacitive element, and wherein the first conductive plate forms an upper plate of the capacitive element and the ground plane forms a lower plate of the capacitive element.

5. The apparatus of claim 1, wherein the first printed inductor is coupled between the first conductive plate and the first conductive via.

6. The apparatus of claim 1, wherein the first printed inductor is a substantially rectangular-shaped conductor having a length at least as long as that of the first conductive via.

7. The apparatus of claim 1, wherein the length of the first conductive via is less than about 62 mils (about 1.57 mm) and wherein the length of the first printed inductor is greater than about 62 mils (about 1.57 mm).

8. The apparatus of claim 1, wherein the second printed inductor is coupled between the first conductive via and the ground plane and wherein the second printed inductor is formed at a substantially right angle relative to the first printed inductor.

9. The apparatus of claim 1, wherein the FSS structure further includes:

a second conductive plate over the first surface of the substrate and separate from the first conductive plate;

a third printed inductor over the first surface of the substrate and coupled to the second conductive plate; and

a second conductive via in the substrate and coupled to the ground plane and the third printed inductor.

10. The apparatus of claim 1, wherein the first conductive plate is substantially square-shaped.

11. The apparatus of claim 1, wherein the first printed inductor has a spiral shape.

12. The apparatus of claim 1, wherein the first printed inductor is a coil having at least one turn.

13. The apparatus of claim 1, further comprising an antenna adjacent to the FSS structure.

14. The apparatus of claim 1, wherein the first printed inductor and the first conductive plate are formed by patterning a single layer of conductive material.

15. An apparatus, comprising:

a first conductive plate on a first surface of a substrate;

a first printed inductor on the first surface of the substrate and coupled to the first conductive plate;

a second conductive plate on a second surface of the substrate; and

a conductive via between the first and second surfaces of the substrate and coupled to the first printed inductor and the second conductive plate; and

a second printed inductor on the second surface of the substrate and coupled to the conductive via.

16. The apparatus of claim 15, wherein the first printed inductor and the first conductive plate are formed by patterning a single layer of conductive material.

17. An artificial magnetic conductor comprising:

a substrate;

a first patterned conductive material over a first surface of the substrate, wherein the first patterned conductive material includes a first inductive element and a first plate of a first capacitive element coupled to the first inductive element;

an electrically conductive material over a second surface of the substrate, wherein the electrically conductive material forms a second plate of the first capacitive element and includes a substantially rectangular-shaped conductor; and

a first conductive via between the first and second surfaces of the substrate and coupled to the first inductive element and the substantially rectangular-shaped conductor, wherein a length of the substantially rectangular-shaped conductor is at least as long as a length of the first conductive via.

18. The artificial magnetic conductor of claim 17, wherein the substrate is a dielectric substrate and wherein the electrically conductive material forms a ground plane of the artificial magnetic conductor.

19. The artificial magnetic conductor of claim 17, further comprising:

a second conductive via between the first and second surfaces of the substrate;

a second patterned conductive material over the first surface of the substrate;

wherein the second patterned conductive material includes a second inductive element and a first plate of a second capacitive element coupled to the second inductive element;

wherein the second inductive element is coupled between the second via and the first plate of the second capacitive element; and

wherein the electrically conductive material forms the second plate of the second capacitive element.

20. A system, comprising:

an antenna to communicate over a wireless local area network (WLAN); and

a frequency selective surface (FSS) structure coupled to the antenna, wherein the FSS includes;

a first conductive plate over a first surface of a substrate; and

a first printed inductor over the first surface of the substrate and coupled to the first conductive plate;

a ground plane over a second surface of the substrate;

a first conductive via in the substrate and coupled to the ground plane and the first printed inductor; and

a second printed inductor over the second surface of the substrate.

21. The apparatus of claim 20, wherein the second printed inductor is formed at a substantially right angle relative to the first printed inductor.

22. The system of claim 20, wherein the ground plane, the first conductive plate, the first printed inductor, the second printed inductor, and the first conductive via form a resonant circuit.

23. The system of claim 20, wherein the second printed inductor is coupled between the first conductive via and the ground plane and wherein the second printed inductor is formed at a substantially right angle relative to the first printed inductor.

24. A method, comprising:

forming a first substantially rectangular-shaped conductor as a first printed inductor over a first surface of a dielectric substrate;

patterning a ground plane over a second surface of the dielectric substrate of an artificial magnetic conductor to alter inductance of the artificial magnetic conductor;

forming a conductive via through the dielectric substrate; and

patterning a conductive material on a second surface of the artificial magnetic conductor to form a second printed inductor that is coupled to the conductive via, wherein the first substantially rectangular-shaped conductor is formed at a substantially right angle relative to the second substantially rectangular-shaped conductor and wherein a length of the first substantially rectangular-shaped conductor is at least as long a length of the conductive via.

25. The method of claim 24, wherein patterning the ground plane on a first surface of the artificial magnetic conductor to increase inductance of the artificial magnetic conductor by forming a first printed inductor on the first surface of the artificial magnetic conductor.

26. The method of claim 24, wherein patterning includes patterning the ground plane on a first surface of the artificial magnetic conductor to increase inductance of the artificial magnetic conductor by forming a first substantially rectangular-shaped conductor on the first surface of the artificial magnetic conductor.