Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
1999-07-19
2001-06-12
Le, Hoanganh (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S850000, C343S853000, C343S859000
Reexamination Certificate
active
06246379
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The invention relates to a quadrifilar helix antenna and is directed more particularly to such an antenna for use in satellite communications and for disposition on seagoing surface vessels.
(2) Description of the Prior Art
The antenna currently used onboard ship in satellite communications bands (about 240 MHz to 410 MHz) is a mechanically steered reflector backed dipole assembly which, because of its weight, must be mounted on deck.
There exists a need for a simple, rugged, relatively small and lightweight antenna which can be mounted on the mast of a surface vessel and be proficient in wideband satellite communications, including Demand Assigned Multiple Access (DAMA) UHF satellite communications functions in the range of 240-320 MHz, and for other satellite communications functions in the range of 320-410 MHz.
SUMMARY OF THE INVENTION
It is, therefore, an object of the invention to provide a relatively small, lightweight, antenna assembly capable of operation in the satellite communications band range of 240-410 MHz, and suitable for mounting on a ship's mast.
A further object of the invention is to provide such an antenna assembly as is strong, rugged, and relatively simple to construct.
A still further object of the invention is to provide such an antenna requiring no external components, such as matching networks, that require placement at critical locations on the antenna and that have to be protected.
With the above and other objects in view, as will hereinafter appear, a feature of the present invention is the provision of a helix antenna comprising a base portion for containing a phase quadrature feed network including a power input, a 90 degree power splitter in communication with the power input, and first and second 180 degree power splitters in communication with the 90 degree power splitter. A support tube is mounted on the base portion, and a plurality of disk separators are mounted on the tube and are spaced from each other and extend radially outwardly from the tube. Four elongated elements are wound around the support tube and are spaced therefrom by the disk separators, the elements being connected to end-most lower and upper ones of the disk separators, the elements extending toward a center feed point of the upper disk separator and comprising radial feed arm portions of the four elements. First and second radially opposite pairs of feed cables are wound about the support tube, attached to the inside middles of the elements and extend from the lower disk separator to the upper disk separator, and are in communication, respectively, with the first and second 180 degree power splitters.
The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of the invention may be employed in various and numerous embodiments without departing from the scope of the invention.
REFERENCES:
patent: 3702481 (1972-11-01), Koller et al.
patent: 5572172 (1996-11-01), Standke et al.
patent: 5793338 (1998-08-01), Standke et al.
patent: 5828348 (1998-10-01), Tassoudji et al.
patent: 5838285 (1998-11-01), Tay et al.
patent: 6011524 (2000-01-01), Jervis
Chen Shih-Chao
Gauthier Robert W.
Lall Prithvi C.
Le Hoang-anh
McGowan Michael J.
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