ANTENNA ASSEMBLIES WITH TAPERED LOOP ANTENNA ELEMENTS AND REFLECTORS

• US 20090146899A1
• Filed: 02/29/2008
• Published: 06/11/2009
• Est. Priority Date: 12/05/2007
• Status: Active Grant

• Current Assignee: Antennas Direct, Inc.
• Original Assignee: Antennas Direct, Inc.
• Inventors: Ross, John Edwin III, Schneider, Richard E.
• Granted Patent: US 7,839,347 B2
• Time in Patent Office: Days
• US Class Current: 343/834
• CPC Class Codes: H01Q 19/10 using reflecting surfaces
• 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

According to various aspects, exemplary embodiments are provided of antenna assemblies. In one exemplary embodiment, an antenna assembly generally includes at least one antenna element having a generally annular shape with an opening. At least one reflector element is spaced-apart from the antenna element for reflecting electromagnetic waves generally towards the antenna element.

Claims

1. An antenna assembly comprising:

at least one tapered loop antenna element having a generally annular shape with an opening; and

at least one reflector element spaced-apart from the tapered loop antenna element for reflecting electromagnetic waves generally towards the tapered loop antenna element, the reflector element including;

a substantially planar surface that is substantially parallel and spaced-apart from the tapered loop antenna element; and

at least one sidewall portion extending outwardly relative to the substantially planar surface generally towards the tapered loop antenna element.

2. The antenna assembly of claim 1, wherein the tapered loop antenna element has spaced-apart end portions defining an open slot extending at least partially between the spaced-apart end portions, whereby the open slot is operable to provide a gap feed for use with a balanced transmission line.

3. The antenna assembly of claim 1, wherein the tapered loop antenna element includes generally circular inner and outer perimeter portions such that the tapered loop antenna element'"'"'s annular shape and opening are generally circular.

4. The antenna assembly of claim 3, wherein the generally circular outer perimeter portion has a diameter of about two hundred twenty millimeters.

5. The antenna assembly of claim 3, wherein the tapered loop antenna element is configured such that a diameter of the generally circular inner perimeter portion is offset from a diameter of the generally circular outer perimeter portion, and wherein the offset diameters provide the tapered loop antenna element with at least one portion wider than at least one other portion.

6. The antenna assembly of claim 5, wherein a midpoint of the diameter associated with the generally circular inner perimeter portion is below a midpoint of the diameter associated with the generally circular outer perimeter portion such that the tapered loop antenna element has a wider upper portion.

7. The antenna assembly of claim 1, wherein the tapered loop antenna element has spaced-apart end portions, and wherein the tapered loop antenna element increases in width from the spaced-apart end portions to a wider middle portion.

8. The antenna assembly of claim 7, further comprising a housing for the tapered loop antenna element and reflector element, and wherein the tapered loop antenna element is positioned with the housing in an orientation such that the wider middle portion is above the spaced-apart end portions.

9. The antenna assembly of claim 1, wherein the tapered loop antenna element includes:

a middle portion;

first and second end portions; and

first and second curved portions extending from the respective first and second end portions to the middle portion, the first and second curved portions each gradually increasing in width from the respective first and second end portions to the middle portion, such that the middle portion is wider than the first and second end portions.

10. The antenna assembly of claim 9, wherein the first curved portion is a mirror-image of the second curved portion.

11. The antenna assembly of claim 1, wherein the at least one sidewall portion of the reflector element includes sidewall portions along the perimeter edges of the reflector element and substantially perpendicular to the substantially planar surface of the reflector element, whereby the sidewall portions are operable for increasing the electrical size of the reflector and for improving impedance matching of the antenna element to which it is coupled.

12. The antenna assembly of claim 1, further comprising a balun.

13. The antenna assembly of claim 1, further comprising a printed circuit board having a balun.

14. The antenna assembly of claim 13, wherein the tapered loop antenna element includes spaced-apart end portions, and wherein the printed circuit board is attached to at least one of the spaced-apart end portions.

15. The antenna assembly of claim 1, further comprising a housing including first and second spaced-apart housing portions for respectively housing the tapered loop antenna element and the reflector element a spaced distance apart.

16. The antenna assembly of claim 15, wherein the housing further includes a middle portion extending between the first and second spaced-apart housing portions such that the middle portion and first and second spaced-apart housing portions cooperatively define a generally U-shaped profile for the housing.

17. The antenna assembly of claim 16, further comprising a digital tuner within the housing for converting digital signals received by the antenna assembly to analog signals.

18. The antenna assembly of claim 1, wherein the tapered loop antenna element is configured for operating within a bandwidth ranging from about 470 megahertz to about 690 megahertz.

19. The antenna assembly of claim 18, wherein the tapered loop antenna element is configured for operating within a second bandwidth ranging from about 174 megahertz to about 216 megahertz.

20. The antenna assembly of claim 1, further comprising a balun for converting between balanced and unbalanced signals and wherein the antenna assembly is configured to have a maximum gain of about 8 dBi (decibels referenced to isotropic gain) and an output with an impedance of about 75 Ohms.

21. The antenna assembly of claim 1, wherein the antenna assembly includes two or more of said tapered loop antenna elements.

22. The antenna assembly of claim 1, wherein the antenna assembly includes two of said tapered loop antenna elements positioned generally side-by-side in a generally figure eight configuration.

23. The antenna assembly of claim 1, wherein the tapered loop antenna element includes a generally circular outer perimeter portion and a generally circular inner perimeter portion offset from the generally circular outer perimeter portion such that a center of the circle generally defined by inner perimeter portion is about twenty millimeters below a center of the circle generally defined by the outer perimeter portion.

24. The antenna assembly of claim 1, wherein at least one sidewall portion of the reflector element is along at least one perimeter edge of the reflector element and substantially perpendicular to the substantially planar surface of the reflector element, and wherein the at least one sidewall has a height of about 2.54 centimeters.

25. The antenna assembly of claim 1, wherein the reflector element is spaced apart from the tapered loop antenna element by about 114.4 millimeters.

26. The antenna assembly of claim 1, wherein the antenna assembly is configured to have at least one operational parameter substantially as shown in FIG. 12.

27. An antenna assembly comprising:

at least one antenna element including;

first and second end portions;

a middle portion;

first and second curved portions extending from the respective first and second end portions to the middle portion such that the antenna element has a generally circular annular shape with a generally circular opening;

the first and second curved portions gradually increasing in width from the respective first and second end portions to the middle portion such that the middle portion is wider than the first and second end portions and such that an outer diameter of the antenna element is offset from an inner diameter of the generally circular opening;

at least one reflector element spaced-apart from the antenna element for reflecting electromagnetic waves generally towards the tapered loop antenna element, the reflector element including;

a substantially planar surface that is substantially parallel with and spaced-apart from the tapered loop antenna element; and

perimeter sidewall portions substantially perpendicular to the substantially planar surface of the reflector element, the perimeter sidewall portions operable as a baffle for deflecting electromagnetic wave energy.

28. The antenna assembly of claim 27, wherein the antenna assembly is tuned to at least one electrical resonant frequency for operating within a bandwidth ranging from about 470 megahertz to about 690 megahertz.

29. The antenna assembly of claim 28, wherein the antenna assembly is tuned to a second electrical resonant frequency for operating within a second bandwidth ranging from about 174 megahertz to about 216 megahertz.

30. The antenna assembly of claim 27, wherein the first and second end portions are spaced apart from each other.

31. The antenna assembly of claim 27, further comprising a housing for the antenna element and reflector element, and wherein the antenna element is positioned with the housing in an orientation such that the middle portion is above the end portions.

32. The antenna assembly of claim 27, wherein the first curved portion is a mirror-image of the second curved portion.

33. The antenna assembly of claim 27, wherein the at least one antenna element includes two or more of said antenna element.

34. An antenna element configured for operating within a bandwidth ranging from about 470 megahertz to about 690 megahertz, the antenna element comprising:

spaced-apart first and second end portions;

a middle portion;

first and second curved portions extending from the respective first and second end portions to the middle portion such that the antenna element has a generally circular annular shape with a generally circular opening;

the first and second curved portions gradually increasing in width from the respective first and second end portions to the middle portion such that the middle portion is wider than the first and second end portions and such that an outer diameter of the antenna element is offset from a diameter of the generally circular opening;

the first curved portion being a mirror image of the second curved portion.

35. The antenna element of claim 34, wherein the outer diameter of the antenna element is about two hundred twenty millimeters.

36. The antenna element of claim 34, wherein a midpoint of the diameter of the generally circular opening is spaced apart from a midpoint of the outer diameter of the antenna element by about twenty millimeters.

37. The antenna element of claim 34, wherein a center of the generally circular opening is offset from a center of the generally circular annular shape.

38. The antenna element of claim 34, wherein the antenna element is configured for operating within a second bandwidth ranging from about 174 megahertz to about 216 megahertz.

39. An antenna assembly including the antenna element of claim 34.

40. The antenna assembly of claim 39, further comprising a reflector element.

41. An antenna assembly operable for receiving high definition television signals having a frequency range of about 470 megahertz and about 690 megahertz, the antenna assembly comprising:

at least one antenna element having a generally annular shape with an opening, and configured for operating within a bandwidth ranging from about 470 megahertz to about 690 megahertz; and

at least one reflector element spaced-apart from the antenna element for reflecting electromagnetic waves generally towards the antenna element.

42. The antenna assembly of claim 41, wherein the antenna element includes:

spaced-apart first and second end portions;

a middle portion;

first and second curved portions extending from the respective first and second end portions to the middle portion such that the antenna element'"'"'s annular shape and opening are generally circular;

the first and second curved portions gradually increasing in width from the respective first and second end portions to the middle portion such that the middle portion is wider than the first and second end portions and such that an outer diameter of the antenna element is offset from a diameter of the generally circular opening.

43. The antenna assembly of claim 42, wherein the first curved portion is a mirror image of the second curved portion.

44. The antenna assembly of claim 42, wherein a center of the generally circular opening is offset from a center of the generally circular annular shape.

45. The antenna assembly of claim 41, wherein the reflector element includes a baffle for deflecting electromagnetic waves.

46. The antenna assembly of claim 45, wherein the baffle is located at least partially along at least one perimeter edge portion of the reflector element.

47. The antenna assembly of claim 41, wherein the reflector element includes:

a substantially planar surface that is substantially parallel with the antenna element; and

at least one sidewall portion extending outwardly relative to the substantially planar surface generally towards the tapered loop antenna element.

48. The antenna assembly of claim 41, wherein the reflector element includes:

a substantially planar surface that is substantially parallel with the antenna element; and

sidewall portions along perimeter edge portions of the reflector element and substantially perpendicular to the substantially planar surface of the reflector element, whereby the sidewall portions are operable as a baffle for deflecting electromagnetic wave energy.