Coupled sectorial loop antenna for ultra-wideband applications

• US 7,268,741 B2
• Filed: 08/22/2005
• Issued: 09/11/2007
• Est. Priority Date: 09/13/2004
• Status: Expired due to Fees

• Current Assignee: EMAG Technologies, Inc.
• Original Assignee: EMAG Technologies, Inc.
• Inventors: Sarabandi, Kamal, Behdad, Nader
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US11/208,700
• Publication Number:
  US 20060055619A1
• Time in Patent Office: 750 Days
• Field of Search: 343/866, 343/867, 343/700.MS, 343/846, 343/795, 343/830, 343/873, 343/844
• US Class Current: 343/866
• CPC Class Codes: H01Q 5/28 Arrangements for establishing polarisation or beam width over two or more different wavebands
• CPC Class Codes: H01Q 5/357 using a single feed point
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A single-element antenna system that provides a wide bandwidth and consistent polarization over the frequency range to which the antenna is impedance matched. In one embodiment, the wideband antenna system includes two parallel coupled sectorial loop antennas (CSLA) that are coupled along an axis of symmetry. In another embodiment, half of the coupled sectorial loop antenna is electrically coupled to a ground plane, where the antenna includes one pie-slice shaped sector and two arches. In alternate embodiments, sections of the sector can be removed to reduce the weight of the antenna system.

Claims

1. A sectorial loop antenna comprising:

a ground plane;

a pie-slice shaped sector having a point positioned adjacent to the ground plane;

a first arch coupled to the ground plane and one side of the sector opposite to the point;

a second arch coupled to the ground plane and an opposite side of the sector opposite to the point; and

a feed electrically coupled to the point of the sector and electrically isolated from the ground plane.

2. The antenna according to claim 1 wherein the sector has an arc angle of about 120°

.

3. The antenna according to claim 1 wherein an input impedance of the feed is a function of R_in, R_out and α

of the sector, where R_in is the inner radius of the arches, R_out is the outer radius of the arches and α

is the arc angle in degrees of half of the sector.

4. The antenna according to claim 3 wherein R_in=27.8 mm, R_out=28 mm and α

=60.

5. The antenna according to claim 3 wherein the thickness of the first and second arches is about 0.4 mm.

6. The antenna according to claim 1 wherein the first arch, the second arch and the sector define an elliptical configuration.

7. The antenna according to claim 1 wherein the first arch, the second arch and the sector define a circular configuration.

8. The antenna according to claim 1 wherein the coupled sectorial loop antenna has an 8.5:

1 impedance bandwidth.

9. The antenna according to claim 1 wherein the feed includes a coaxial connector, wherein an inner conductor of the coaxial connector is coupled to the point of the sector and an outer conductor of the coaxial connector is coupled to the ground plane.

10. A coupled sectorial loop antenna comprising:

a ground plane;

a first pie-slice shaped sector and a second pie-slice shaped sector each having a point positioned adjacent to the ground plane and defining a pie-sliced shaped open portion therebetween;

a first arch electrically coupled to the ground plane and an end of the first sector opposite to the point of the first sector;

a second arch electrically coupled to the ground plane and an end of the second sector opposite to the point of the second sector; and

a feed electrically coupled to both points of the first and second sectors and electrically isolated from the ground plane.

11. The antenna according to claim 10 wherein the open portion is between −

30° and

+30°

relative to a radius that bisects the open portion.

12. The antenna according to claim 10 wherein the first and second sectors have an arc angle of 30°

.

13. The antenna according to claim 10 wherein a portion of the first and second sectors is removed.

14. The antenna according to claim 13 wherein the removed portions of the sectors are between 40°

and 50°

of the first sector and −

40° and

−

50°

of the second sector relative to a radius that bisects the open portion.

15. The antenna according to claim 10 wherein an input impedance of the feed is a function of R_in, R_out and α

of the first and second sectors, where R_in is the inner radius of the arches, R_out is the outer radius of the arches and α

is an arc angle in degrees.

16. The antenna according to claim 15 wherein R_in=27.8 mm, R_out=28 mm and α

=60°

.

17. The antenna according to claim 10 wherein the thickness of the arches is about 0.4 mm.

18. The antenna according to claim 10 wherein the first arch, the second arch and the sector define an elliptical configuration.

19. The antenna according to claim 10 wherein the first arch, the second arch and the sector define a circular configuration.

20. The antenna according to claim 10 wherein the coupled sectorial loop antenna has an 8.5:

1 impedance bandwidth.

21. The antenna according to claim 10 wherein the feed includes a coaxial connector, wherein an inner conductor of the coaxial connector is coupled to the point of the sectors and an outer conductor of the coaxial connector is coupled to the ground plane.

22. A sectorial loop antenna comprising:

a ground plane;

a pie-slice shaped sector having a point positioned adjacent to the ground plane, said pie-slice shaped sector including at least one pie-slice shaped portion being removed therefrom;

a first arch coupled to the ground plane and one side of the sector opposite to the point;

a second arch coupled to the ground plane and an opposite side of the sector opposite to the point; and

a feed electrically coupled to the point of the sector and electrically isolated from the ground plane.

23. The antenna according to claim 22 wherein the at least one removed portion from the sector is a single removed portion centrally located within the sector.

24. The antenna according to claim 23 wherein the removed portion from the sector is between −

30° and

+30°

relative to a radius that bisects the sector.

25. The antenna according to claim 22 wherein the removed portion of the sector is three removed portions.

26. The antenna according to claim 25 wherein the removed portions of the sector include a center removed portion between −

30° and

+30°

relative to a radius that bisects the sector, a first side removed portion between 40° and

50°

relative to the radius on one side of the center removed portion and a second side removed portion between −

40° and

−

50°

relative to the radius on the other side of the center removed portion.

27. The antenna according to claim 22 where the sector has an arch angle of about 120°

.

28. The antenna according to claim 22 wherein the first arch, the second arch and the sector define an elliptical configuration.

29. The antenna according to claim 22 wherein the first arch, the second arch and the sector define a circular configuration.

30. The antenna according to claim 22 wherein the feed includes a coaxial connector, wherein an inner conductor of the coaxial connector is coupled to the point of the sector and an outer conductor of the coaxial connector is coupled to the ground plane.