Wideband low profile spiral-shaped transmission line antenna

• US 20030156065A1
• Filed: 12/27/2002
• Published: 08/21/2003
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: SkyCross Co., Ltd.
• Original Assignee: SkyCross, Inc.
• Inventors: Kim, Young-Ki, Jo, Young-Min, Kralovec, Jay A., Sullivan, Sean F., Han, Kyu-Young
• Granted Patent: US 6,842,158 B2
• Time in Patent Office: Days
• US Class Current: 343/700MS
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 9/27 Spiral antennas
• CPC Class Codes: H01Q 9/285 Planar dipole H01Q9/065 takes precedence; patch antenna H01Q9/0407

Abstract

An antenna incorporating slow wave structures. The antenna comprises at least two conductive serpentine structures disposed on a dielectric substrate and further comprising an oppositely disposed conductive top plate electrically connected to the conductive serpentine structures and farther electromagnetically connected thereto. In one embodiment the antenna further comprises a ground plane below the dielectric substrate.

Claims

1. An antenna comprising:

a dielectric substrate;

a slow wave structure disposed on a first surface of the dielectric substrate;

a top conductor disposed on a second surface, opposing the first surface of the dielectric substrate; and

a conductive via extending through the dielectric substrate for connecting the slow wave structure to the top conductor.

2. The antenna of claim 1 wherein the slow wave structure comprises at least one conductor having a spiral shape.

3. The antenna of claim 1 comprising a first and a second conductive via disposed within the dielectric substrate and electrically connected to the top conductor, wherein the slow wave structure comprises a first and a second conductor each having a serpentine shape, and wherein a first end of the first conductor is connected to the first conductive via, and wherein a first end of the second conductor is connected to the second conductive via, and wherein a second end of the first conductor is a ground terminal for the antenna, and wherein a second end of the second conductor is a signal terminal for the antenna.

4. The antenna of claim 3 wherein the serpentine shape is selected from among a spiral comprising linear arms, a spiral comprising curved arms, a meandering shape, a sawtooth wave shape and a square wave shape.

5. The antenna of claim 3 wherein the top conductor comprises an elongated segment having a first and a second arm extending in the same direction therefrom, and wherein the first conductive via is positioned at an end of the first arm and the second conductive via is positioned at the end of the second arm.

6. The antenna of claim 3 wherein the serpentine shape comprises a spiral-shape, and wherein the current flow is in the same direction through radially adjacent spiral arms of the first conductor, and wherein the current flow is in the same direction through radially adjacent spiral arms of the second conductor.

7. The antenna of claim 6 wherein the first and the second conductors comprise opposingly wound spirals.

8. The antenna of claim 7 wherein the magnetic fields produced by the current flow through the first and the second conductors add constructively in the far field.

9. The antenna of claim 8 wherein a first electric field is produced by the sum of the magnetic fields, and wherein a current flow through the top conductor produces a second electric field, and wherein the first and the second electric fields add constructively in the far field.

10. The antenna of claim 1 wherein the top conductor comprises an elongated segment having two parallel arms extending from a first side thereof, and wherein the slow wave structure comprises a ground terminal and a feed terminal disposed along an edge of the dielectric substrate, and wherein the elongated segment is disposed approximately above the edge.

11. The antenna of claim 1 wherein the top conductor comprises an elongated segment having two parallel arms extending from a first side thereof, and wherein the slow wave structure comprises a ground terminal and a feed terminal disposed along a first edge of the dielectric substrate, and wherein the elongated segment is disposed above a second edge of the dielectric substrate spaced apart from and parallel to the first edge.

12. The antenna of claim 1 wherein the slow wave structure comprises two differently sized spiral-shaped conductive elements.

13. The antenna of claim 1 wherein the slow wave structure comprises three spiral-shaped conductive elements.

14. The antenna of claim 1 wherein the slow wave structure comprises one spiral-shaped conductive element.

15. The antenna of claim 1 wherein the slow wave structure comprises two serpentine conductors.

16. The antenna of claim 1 further comprising an L-shaped conductive element disposed proximate the slow wave structure for connecting to ground.

17. An antenna comprising:

a dielectric substrate;

a slow wave structure disposed on a first surface of the dielectric substrate and further comprising a feed terminal and a ground terminal;

a top conductor disposed on a second surface, opposing the first surface of the dielectric substrate;

a conductive via extending through the dielectric substrate for connecting the slow wave structure to the top conductor; and

a ground plane facing and spaced apart from the first surface and electrically connected to the ground terminal.

18. The antenna of claim 17 wherein the slow wave structure has a physical length, and wherein the effective electrical length of the slow wave structure is greater than the physical length.

19. The antenna of claim 17 wherein an angle formed by the plane of the dielectric substrate and the ground plane is adjustable.

20. The antenna of claim 19 wherein the operating characteristics of the antenna are a function of the angle.

21. The antenna of claim 17 wherein the slow wave structure comprises a first and a second serpentine conductor, and wherein an end of the first serpentine conductor comprises the feed terminal, and wherein an end of the second serpentine conductor comprises the ground terminal.

22. The antenna of claim 21 wherein the first and the second serpentine conductors each comprise a spiral-shaped conductor.

23. The antenna of claim 21 wherein the first and the second serpentine conductors are positioned in a side by side orientation.

24. An antenna comprising:

a dielectric substrate having first and second opposing surfaces;

a conductive region disposed on the first surface;

a first slow wave structure disposed on the second surface and electrically connected to the conductive region;

a second slow wave structure disposed on the second surface and electrically connected to the conductive region;

wherein a region of the first slow wave structure forms an antenna ground terminal;

wherein a region of the second slow wave structure forms an antenna feed terminal; and

a ground plane spaced apart from the dielectric substrate, wherein the second surface is oriented in facing relation to the ground plane.

25. The antenna of claim 24 wherein the first and the second slow wave structures each comprise a serpentine conductor.

26. The antenna of claim 24 wherein the first and the second slow wave structures are electrically connected to the conductive region through a first and a second conductive via, respectively, extending through the dielectric substrate.

27. An antenna for connecting to a communications device, comprising:

a dielectric substrate having first and second opposing surfaces;

a conductive region disposed on the first surface;

a first slow wave structure disposed on the second surface and electrically connected to conductive region;

a second slow wave structure disposed on the second surface and electrically connected to the conductive region;

wherein a region of the first slow wave structure forms an antenna ground terminal;

wherein a region of the second slow wave structure forms an antenna feed terminal;

a ground plane spaced apart from the dielectric substrate, wherein the second surface is oriented in facing relation to the ground plane; and

a feed line extending from the feed terminal for connection to the communications device, wherein the feed line extends over and is spaced-apart from the ground plane a predetermined distance as determined by the desired performance characteristics of the antenna.

28. The antenna of claim 27 wherein the feed line comprises a conductive plate having a predetermined width as determined by the desired performance characteristics of the antenna.

30. The antenna of claim 28 wherein the feed line comprises a first segment extending from the feed terminal toward the ground plane, a second segment electrically connected to a printed circuit board trace of the communications device, and a third substantially horizontal segment connecting the first and the third segments, wherein the third segment has a predetermined width and distance to the ground plane so as to achieve the desired antenna performance parameters.

31. An antenna for connecting to a signal terminal of a communications device, comprising:

a radiating element;

a feed terminal connected to the radiating element;

a ground plane underlying and spaced apart from the radiating element; and

a feed line comprising a first segment downwardly directed from the feed terminal toward the ground plane, a second segment electrically connected to the signal terminal, and a third substantially horizontal segment connecting the first and the third segments, wherein the third segment comprises a conductive plate having a predetermined width and distance to the ground plane so as to achieve the desired antenna performance parameters.