Base station antennas with sector splitting in the elevation plane based on frequency band

Abstract

Base station antennas are provided that include a first array of radiating elements that is configured to form a first antenna beam that has a first downtilt angle in response to a first RF signal that is input at the first RF port and a second array of radiating elements that is configured to form a second antenna beam that has a second downtilt angle in response to a second RF signal that is input at the second RF port. The second downtilt angle is less than the first downtilt angle. The first antenna beam is configured to only provide coverage to users within a first portion of a coverage area of the base station antenna that is close to the base station antenna and the second antenna beam is configured to provide coverage to users within a second portion of the coverage area that extends farther from the base station antenna than does the first portion.

That which is claimed is: 
     
         1 . A base station antenna, comprising:
 a first radio frequency (“RF”) port;   a second RF port;   a first antenna array having a plurality of sub-arrays;   a feed network that couples the first and second RF ports to the first antenna array, the feed network including:
 a beamforming network that has a first input that is coupled to the first RF port, a second input that is coupled to the second RF port and a plurality of outputs; and 
 a plurality of RF transmission paths that connect each output of the beamforming network to a respective one of the sub-arrays, 
   wherein the feed network is configured to impart a phase taper to sub-components of first and second RF signals that are input at the respective first and second RF ports in order to electronically downtilt first and second antenna beams that are generated by the base station antenna in response to the first and second RF signals.   
     
     
         2 . The base station antenna of  claim 1 , wherein the first antenna beam is configured to only provide coverage to users within a first portion of a coverage area that is close to the base station antenna and the second antenna beam is configured to provide coverage to users within a second portion of the coverage area that extends farther from the base station antenna than does the first portion. 
     
     
         3 . The base station antenna of  claim 2 , wherein the second antenna beam provides coverage to users in less than all of the coverage area. 
     
     
         4 . The base station antenna of  claim 2 , wherein the first portion of the coverage area comprises a generally pie-shaped region having a point that extends outwardly from the base station antenna, and the second portion of the coverage area comprises a section of an annular region surrounding the base station that extends outwardly from the first portion of the coverage area. 
     
     
         5 . The base station antenna of  claim 1 , further comprising an adjustable phase shifter disposed along each of the RF transmission paths. 
     
     
         6 . The base station antenna of  claim 1 , wherein the first antenna beam and the second antenna beam split a sector covered by the base station antenna in an elevation plane of the base station antenna. 
     
     
         7 . The base station antenna of  claim 1 , wherein the first and second antenna beams have the same boresight pointing direction in the azimuth plane. 
     
     
         8 . The base station antenna of  claim 1 , wherein a half power beamwidth of the second antenna beam in an elevation plane of the base station antenna is less than a half power beamwidth of the first antenna beam in the elevation plane. 
     
     
         9 . The base station antenna of  claim 1 , wherein the first RF port is coupled to a radio configured to operate in a 3.55-3.70 GHz Citizen Broadband Radio Service (“CBRS”) frequency band and the second RF port is coupled to a radio configured to operate in a 3.70-3.98 GHz C-band frequency band. 
     
     
         10 . A base station antenna, comprising
 a multi-column array having a plurality of columns of radiating elements, the multi-column array configured to operate as a static sector antenna in a first frequency band and to operate as a beamforming antenna in a second frequency band,   wherein all of the columns in the multi-column array operate in the second frequency band while less than all of the columns in the multi-column array operate in the first frequency band.   
     
     
         11 . The base station antenna of  claim 10 , wherein the columns in the multi-column array operate in the first frequency band are non-adjacent columns. 
     
     
         12 . The base station antenna of  claim 10 , wherein a number of columns in the multi-column array that operate in the first frequency band may be half the number of columns half number of columns in the multi-column array. 
     
     
         13 . The base station antenna of  claim 10 , wherein the first frequency band is the 3.55-3.70 GHz CBRS frequency band and the second frequency band is the 3.70-3.98 GHz C-band frequency band. 
     
     
         14 . The base station antenna of  claim 10 , wherein a first antenna beam generated by the multi-column array in response to an RF signal in the first frequency band is configured to only provide coverage to users within a first portion of the coverage area that is close to the base station antenna and a second antenna beam generated by the multi-column array in response to an RF signal in the second frequency band is configured to provide coverage to users within a second portion of the coverage area that is farther from the base station antenna than the first portion. 
     
     
         15 . The base station antenna of  claim 14 , wherein the second antenna beam provides coverage to users in less than all of the coverage area. 
     
     
         16 . The base station antenna of  claim 15 , wherein the first portion of the coverage area comprises a generally pie-shaped region having a point that extends outwardly from the base station antenna, and the second portion of the coverage area comprises a section of an annular region surrounding the base station that extends outwardly from the first portion of the coverage area. 
     
     
         17 . The base station antenna of  claim 16 , wherein an outer portion of the first portion of the coverage area overlaps an inner portion of the second portion of the coverage area. 
     
     
         18 . A method of operating a base station antenna that has a predefined coverage area, the method comprising:
 forming a first antenna beam in response to a first radio frequency (“RF”) signal that provides coverage only to users within a first portion of the coverage area that is close to the base station antenna; and   forming a second antenna beam in response to a second RF signal that provides coverage to users within a second portion of the coverage area that extends outwardly beyond the first portion.   
     
     
         19 . The method of  claim 18 , wherein the second antenna beam provides coverage to users in less than all of the coverage area. 
     
     
         20 . The method of  claim 18 , wherein a half power beamwidth of the second antenna beam in an elevation plane of the base station antenna is less than a half power beamwidth of the first antenna beam in the elevation plane.