Antenna assemblies with antenna elements and reflectors
According to various aspects, exemplary embodiments are provided of antenna assemblies. In an exemplary embodiment, an antenna assembly generally includes at least one tapered loop antenna element having a generally annular shape with an opening. An antenna assembly may also include a rotatably convertible support including a base and an upper portion coupled to a tapered loop antenna element in some embodiments. The upper portion is rotatable relative to the base between a first configuration for supporting the tapered loop antenna element on a horizontal surface and a second configuration for supporting the tapered loop antenna element from a vertical surface.
1. An antenna assembly comprising:
a tapered loop antenna element having a generally annular shape with an opening; and
a rotatably convertible support including a base and an upper portion coupled to the tapered loop antenna element, the upper portion rotatable relative to the base between a first configuration for supporting the tapered loop antenna element on a horizontal surface and a second configuration for supporting the tapered loop antenna element from a vertical surface;
wherein the rotatably convertible support is configured such that:
rotation of the upper portion relative to the base in a first direction converts the rotatably convertible support from the first configuration to the second configuration; and
rotation of the upper portion relative to the base in a second direction opposite the first direction converts the rotatably convertible support from the second configuration to the first configuration.
2. The antenna assembly of claim 1 , configured for operating within a bandwidth ranging from about 470 megahertz to about 690 megahertz, the tapered loop antenna element comprising:
spaced-apart first and second end portions;
a middle portion; and
first and second curved portions extending from the respective first and second end portions to the middle portion such that the tapered loop 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 tapered loop 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.
3. The antenna assembly of claim 2 , wherein the outer diameter of the tapered loop antenna element is about two hundred twenty millimeters.
4. The antenna assembly of claim 2 , wherein a midpoint of the diameter of the generally circular opening is spaced apart from a midpoint of the outer diameter of the tapered loop antenna element by about twenty millimeters.
5. The antenna assembly of claim 2 , wherein a center of the generally circular opening is offset from a center of the generally circular annular shape.
6. The antenna assembly of claim 2 , configured for operating within a second bandwidth ranging from about 174 megahertz to about 216 megahertz.
7. The antenna assembly of claim 1 , further comprising a reflector element spaced-apart from the tapered loop antenna element and including a baffle for reflecting electromagnetic waves generally towards the tapered loop antenna element.
8. The antenna assembly of claim 1 , wherein the rotatably convertible support includes a threaded stem portion and a threaded opening for receiving the threaded stem portion.
9. The antenna assembly of claim 8 , wherein:
the threaded stem portion extends upwardly from the base; and
the threaded opening is defined by the upper portion.
10. The antenna assembly of claim 1 , further comprising one or more stops for retaining the rotatably convertible support in the first configuration and/or second configuration.
11. The antenna assembly of claim 1 configured for operating within a bandwidth ranging from about 470 megahertz to about 690 megahertz, the tapered loop antenna element including:
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; and
generally circular inner and outer perimeter portions such that the tapered loop antenna element's annular shape and opening are generally circular.
12. The antenna assembly of claim 11 , wherein:
the generally circular outer perimeter portion has a diameter of about two hundred twenty millimeters; and/or
a center of the circle generally defined by the inner perimeter portion is about twenty millimeters below a center of the circle generally defined by the outer perimeter portion.
13. The antenna assembly of claim 11 , 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
the offset diameters provide the tapered loop antenna element with at least one portion wider than at least one other portion.
14. The antenna assembly of claim 13 , 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.
15. The antenna assembly of claim 11 , wherein:
the tapered loop antenna element increases in width from the spaced-apart end portions to a wider middle portion; and
the tapered loop antenna element is positioned in an orientation such that the wider middle portion is above the spaced-apart end portions and rotatably convertible support when supported from the vertical surface in the second configuration.
16. The antenna assembly of claim 11 , further comprising a printed circuit board having a balun, and wherein the printed circuit board is attached to at least one of the spaced-apart end portions of the tapered loop antenna element.
17. The antenna assembly of claim 1 , further comprising a digital tuner for converting digital signals received by the antenna assembly to analog signals.
18. The antenna assembly of claim 1 , wherein the antenna assembly is tuned to a first electrical resonant frequency for operating within a first bandwidth ranging from about 470 megahertz to about 690 megahertz and is tuned to a second electrical resonant frequency for operating within a second bandwidth ranging from about 174 megahertz to about 216 megahertz.
19. 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.
20. The antenna assembly of claim 1 , further comprising a reflector element spaced-apart from the tapered loop antenna element for reflecting electromagnetic waves generally towards the tapered loop antenna element.
21. An antenna assembly comprising:
a tapered loop antenna element having a generally annular shape with an opening;
a rotatably convertible support including a base and an upper portion coupled to the tapered loop antenna element, the upper portion rotatable relative to the base between a first configuration for supporting the tapered loop antenna element on a horizontal surface and a second configuration for supporting the tapered loop antenna element from a vertical surface;
one or more stops for retaining the rotatably convertible support in the first configuration and/or second configuration;
wherein:
the one or more stops include first and second stops configured to be engagingly received within first and second openings, respectively, for retaining the rotatably convertible support in the corresponding first or second configuration;
the engagement of the first stop within the first opening inhibits relative rotation of the upper portion and the base thus helping retain the rotatably convertible support in the first configuration; and
the engagement of the second stop within the second opening inhibits relative rotation of the upper portion and the base thus helping retain the rotatably convertible support in the second configuration.
22. The antenna assembly of claim 21 , wherein:
the upper portion includes the first and second stops; and
the base includes the first and second openings.
23. The antenna assembly of claim 21 , wherein the first and second stops includes one or more of a projection, nub, protrusion, and/or protuberance.
24. The antenna assembly of claim 21 , wherein the one or more stops are configured to provide a tactile and/or audible indication to a user to stop rotating the upper portion relative to the base when the first and second stop is engaged into the corresponding first or second opening.