LINEAR ANTENNA ARRAY WITH AZIMUTH BEAM AUGMENTATION BY AXIAL ROTATION
An antenna array with azimuth beam width that can be continuously augmented through on-axis rotation of a single-column or a dual-column linear array is disclosed. Alternate radiating elements in the vertical direction are arranged on separate reflectors which are movable to change their angle in the azimuth to alter beam width.
1 . An antenna for a wireless network, comprising:
a first reflector having a first plurality of radiators coupled thereto; and
a second reflector having a second plurality of radiators coupled thereto;
wherein the first and second plurality of radiators are arranged in a generally vertical direction with alternate radiators alternately configured on said first and second reflectors,
wherein said first and second reflectors are rotatable in opposite angular directions in the azimuth to alter signal beam width.
2 . The antenna of claim 1 , wherein said first and second reflectors are partially overlapping with an interlocking comb shape and provide a generally rectangular shape in combination.
3 . The antenna of claim 2 , wherein alternate radiators are configured in notched portions of the opposite comb shaped reflector.
4 . The antenna of claim 1 , wherein the first and second plurality of radiators comprise patch antenna radiating elements.
5 . The antenna of claim 1 , wherein the first and second reflectors are generally planar.
6 . The antenna of claim 1 , wherein the first and second reflectors are movable through an angular range of between 0 degrees and about 40 degrees and wherein half power beam width is variable between about 36 and 120 degrees.
7 . The antenna of claim 1 , wherein the first and second plurality of radiators are offset from a center axis of the vertical arrangement in opposite directions by a total distance d in the azimuth when the reflectors are at a 0 degree relative angle.
8 . The antenna of claim 7 , wherein the first and second reflector are offset from a rotation axis by an amount Δd, wherein Δd is substantially smaller than d.
9 . The antenna of claim 8 , wherein Δd is substantially smaller than the operational wavelength of the antenna.
10 . The antenna of claim 1 , further comprising a shaft extending in the vertical direction and wherein said first and second reflectors are coupled to said shaft.
11 . An antenna array, comprising:
a first reflector structure having plural reflector panels spaced apart in a vertical direction;
a first plurality of radiators coupled to the plural reflector panels of the first reflector structure and configured in pairs on each panel, wherein the radiators in each pair are spaced apart in an azimuth direction;
a second reflector structure having plural reflector panels spaced apart in said vertical direction and alternating with the plural reflector panels of said first reflector structure; and
a second plurality of radiators coupled to the plural reflector panels of the second reflector structure and configured in pairs on each panel, wherein the radiators in each pair are spaced apart in said azimuth direction;
wherein the first and second plurality of radiators are arranged in two columns extending in the vertical direction when the plural panels of the first and second reflector structures are in a first generally aligned configuration, and
the first and second plurality of radiators are generally amplitude tapered in alternate fashion in the vertical direction;
wherein the plural panels of the first and second reflector structures are movable together in opposite angular directions in the azimuth to alter signal beam width of the antenna array.
12 . The antenna array of claim 11 , wherein the plural panels of the first and second reflector structures form a generally X shaped overall configuration when moved in opposite directions away from said aligned configuration.
13 . The antenna array of claim 11 , wherein the plural panels of the first and second reflector structures are planar and generally rectangular in shape.
14 . The antenna array of claim 11 , wherein the array has a relatively narrow beam width in said first generally aligned configuration and a beam width which increases with the angular separation of the first and second reflector structures in the azimuth.
15 . The antenna of claim 14 , wherein the first and second reflector structures are rotatable in opposite angular directions in the azimuth through a range of about 40 degrees and wherein the half power beam width ranges between about 36 and 102 degrees.
16 . The antenna array of claim 11 , further comprising a shaft extending in the vertical direction and wherein said plural panels of said first and second reflector structures are coupled to said shaft.
17 . The antenna array of claim 11 , wherein said two columns of radiators formed when the plural panels of the first and second reflector structures are in a first generally aligned configuration are spaced apart a distance d, wherein the first and second reflector panels are offset from a rotation axis by an amount Δd, and wherein Δd is substantially smaller than d.
18 . The antenna of claim 11 , wherein the first and second plurality of radiators comprise patch radiating elements.
19 . A method of adjusting signal beam width in a wireless antenna having a plurality of radiators configured on plural separate reflector panels, the method comprising:
providing the reflector panels in a first configuration to provide a first signal beam width; and rotating the panels in opposite angular directions in the azimuth to a second configuration to provide a second signal beam width.
20 . The method of claim 19 , wherein said plural panels comprise first and second groups of panels movable together and wherein plural radiators are configured on each panel.