Beamforming antennas with omnidirectional coverage in the azimuth plane
A base station antenna includes a plurality of pairs of RF ports, a tubular reflector, a plurality of columns of first frequency band radiating elements that are mounted to extend outwardly from the tubular reflector, the columns extending around a periphery of the tubular reflector and grouped into a plurality of column groups, where each column group includes at least three columns, and a plurality of feed networks, where each feed network connects one of the pairs of RF ports to a respective one of the column groups.
1 . A base station antenna, comprising:
a plurality of pairs of radio frequency (“RF”) ports;
a tubular reflector;
a plurality of columns of first frequency band radiating elements that are mounted to extend outwardly from the tubular reflector, the columns extending around a periphery of the tubular reflector and grouped into a plurality of column groups, where each column group includes at least two columns;
a first feed network that connects both of the RF ports in a first of the plurality of pairs of RF ports to each column in a first of the column groups; and
a second feed network that connects both of the RF ports in a second of the plurality of pairs of RF ports to each column in a second of the column groups;
wherein the plurality of column groups are configured to generate sector antenna beams that provide coverage to respective ones of a plurality of sectors.
2 . The base station antenna of claim 1 , wherein the tubular reflector includes a plurality of flat faces.
3 . The base station antenna of claim 2 , wherein each pair of adjacent flat faces define a respective angle within an interior of the tubular reflector, and the sum of the angles defined by the pairs of adjacent faces is equal to 360°.
4 . The base station antenna of claim 1 , wherein the column groups are arranged in pairs, and each pair of column groups is configured to be coupled to a respective one of a plurality of four-port radios.
5 . The base station antenna of claim 4 , wherein the first column group of each pair of column groups is configured to be coupled to first and second ports of the respective one of the four-port radios, and the second column group of each pair of column groups is configured to be coupled to third and fourth ports of the respective one of the four-port radios.
6 . The base station antenna of claim 4 in combination with the plurality of four-port radios, wherein each four-port radio is configured to support four-input-four-output multi-input-multi-output (“MIMO”) communications through a respective pair of adjacent column groups.
7 . The base station antenna of claim 1 , wherein the plurality of columns of first frequency band radiating elements comprises at least twelve columns of first frequency band radiating elements.
8 . The base station antenna of claim 1 , wherein the plurality of columns of first frequency band radiating elements comprises eighteen columns of first frequency band radiating elements that are divided into six column groups having three columns of first frequency band radiating elements each, wherein each column group is configured to provide coverage to a 60° sector in an azimuth plane.
9 . The base station antenna of claim 1 , further comprising a plurality of radios that are mounted within a center of the tubular reflector.
10 . The base station antenna of claim 9 , wherein each radio includes a plurality of inwardly extending heat fins that are configured to contact a pole on which the base station antenna is mounted.
11 . The base station antenna of claim 1 , wherein each feed network includes first and second phase shifters for each column of first frequency band radiating elements, and wherein a single respective remote electronic tilt actuator is provided to adjust the phase shifters associated with the columns of first frequency band radiating elements included in each column group.
12 . The base station antenna of claim 1 , wherein the tubular reflector has a substantially circular cross-section.
13 . The base station antenna of claim 1 , wherein the plurality of columns of first frequency band radiating elements comprises twenty-four columns of first frequency band radiating elements that are divided into eight column groups having three columns of first frequency band radiating elements each, wherein each column group is configured to provide coverage to a 45° sector in an azimuth plane.
14 . The base station antenna of claim 1 , wherein adjacent columns are spaced apart by less than 0.6 of a wavelength that corresponds to a center frequency of the first frequency band.