Phased array line feed for a reflector antenna

Abstract

A phased array line feed for a reflector antenna, including a plurality of substantially parallel metallic rods and a phase/power switching matrix electrically connected to the metallic rods. The phase/power switching matrix may steer a beam of the reflector antenna by adjusting the phase and/or power difference between the metallic rods. The phased array line feed may also include a plurality of substantially parallel metallic disks. The metallic rods may extend through the metallic disks substantially perpendicular to the metallic discs. The metallic discs may be equally spaced and the diameter of the metallic disks may decrease along the length of the metallic rods. Alternatively, the diameters of the metallic discs may be equal and the distances between the metallic discs may decrease along the length of the metallic rods.

What is claimed is: 
     
         1 . A reflector antenna, comprising:
 a spherical reflective surface; and   a phased array line feed comprising:   a plurality of substantially parallel metallic rods configured to receive or emit electromagnetic waves reflected off the spherical reflective surface, and   a phase/power switching matrix electrically connected to the substantially parallel metallic rods.   
     
     
         2 . The reflector antenna of  claim 1 , wherein the phase/power switching matrix steers a beam of the reflector antenna by adjusting a phase difference between the substantially parallel metallic rods. 
     
     
         3 . The reflector antenna of  claim 1 , wherein the phase/power switching matrix controls the shape of the reflector antenna beam by adjusting a power difference between the substantially parallel metallic rods. 
     
     
         4 . The reflector antenna of  claim 1 , further comprising:
 a plurality of substantially parallel metallic disks,   wherein each of the substantially parallel metallic rods extends from a base of the phased array line feed through the substantially parallel metallic disks substantially perpendicular to the substantially parallel metallic disks to a vertex of the phased array line feed.   
     
     
         5 . The reflector antenna of  claim 4 , wherein the substantially parallel metallic disks are spaced apart by a distance of approximately ½ of a wavelength of interest of the reflector antenna. 
     
     
         6 . The reflector antenna of  claim 4 , wherein distances between the substantially parallel metallic disks decrease from a maximum at the base of the phased array line feed to a minimum at the vertex of the phased array line feed. 
     
     
         7 . The reflector antenna of  claim 4 , wherein diameters of the substantially parallel metallic disks decrease from a maximum at the base of the phased array line feed to a minimum at the vertex of the phased array line feed. 
     
     
         8 . The reflector antenna of  claim 1 , wherein:
 the substantially parallel metallic rods are spaced apart at a base of the phased array line feed by a distance of approximately N/4 of a wavelength of interest of the reflector antenna; and   N is an integer.   
     
     
         9 . The reflector antenna of  claim 1 , wherein distances between the substantially parallel metallic rods decrease from a base of the phased array line feed base to a vertex of the phased array line feed. 
     
     
         10 . The reflector antenna of  claim 1 , wherein the phased array line feed has a length of approximately 12 percent of the diameter of the reflector antenna. 
     
     
         11 . A method of making a reflector antenna having a wavelength of interest, the method comprising:
 providing a spherical reflective surface; and   providing a phased array line feed by:   providing a plurality of substantially parallel metallic rods configured to receive or emit electromagnetic waves reflected off the spherical reflective surface, and   electrically connecting a phase/power switching matrix to the substantially parallel metallic rods.   
     
     
         12 . The method of  claim 11 , wherein the phase/power switching matrix steers a beam of the reflector antenna by adjusting a phase difference between the substantially parallel metallic rods. 
     
     
         13 . The method of  claim 11 , wherein the phase/power switching matrix controls the shape of the reflector antenna beam by adjusting a power difference between the substantially parallel metallic rods. 
     
     
         14 . The method of  claim 11 , further comprising:
 providing a plurality of substantially parallel metallic disks,   wherein each of the substantially parallel metallic rods extends from a base of the phased array line feed through the substantially parallel metallic disks substantially perpendicular to the metallic disks to a vertex of the phased array line feed.   
     
     
         15 . The method of  claim 14 , wherein the substantially parallel metallic disks are spaced apart by a distance of approximately ½ the wavelength of interest. 
     
     
         16 . The method of  claim 14 , wherein distances between the substantially parallel metallic disks decrease from a maximum at the base of the phased array line feed to a minimum at the vertex of the phased array line feed. 
     
     
         17 . The method of  claim 14 , wherein diameters of the substantially parallel metallic disks decrease from a maximum at the base of the phased array line feed to a minimum at the vertex of the phased array line feed. 
     
     
         18 . The method of  claim 11 , wherein:
 the substantially parallel metallic rods are spaced apart by a distance of approximately N/4 the wavelength of interest at a base of the phased array line feed; and   N is an integer.   
     
     
         19 . The method of  claim 11 , wherein distances between the substantially parallel metallic rods decrease from a base of the phased array line feed base to a vertex of the phased array line feed. 
     
     
         20 . The method of  claim 11 , wherein the phased array line feed has a length of approximately 12 percent of the diameter of the reflector antenna.