Parabolic reflector antennas having feeds with enhanced radiation pattern control
Parabolic reflector antennas advantageously utilize feed boom mounted dielectric lens structures to support enhanced radiation pattern control. A parabolic reflector antenna includes a dish reflector, a feed boom waveguide having a proximal end coupled to the dish reflector, a sub-reflector assembly and a dielectric lens. The sub-reflector assembly may include a dielectric block coupled to a distal end of the feed boom waveguide and a sub-reflector adjacent a distal end of the dielectric block. The dielectric lens may be provided on the feed boom waveguide at a location intermediate the proximal and distal ends of the feed boom waveguide.
1. A parabolic reflector antenna, comprising:
a dish reflector;
a feed boom waveguide having a proximal end coupled to said dish reflector, said feed boom waveguide comprising inner and outer waveguides in coaxial alignment;
a sub-reflector assembly comprising a dielectric block coupled to a distal end of said feed boom waveguide and a sub-reflector adjacent a distal end of the dielectric block; and
a dielectric lens on said feed boom waveguide at a location intermediate the proximal and distal ends thereof, said dielectric lens surrounding a portion of the inner waveguide, but not surrounding the outer waveguide.
2. The antenna of claim 1 , wherein said dielectric lens and said feed boom waveguide are in coaxial alignment.
3. The antenna of claim 1 , wherein said feed boom waveguide is a dual-band waveguide.
4. The antenna of claim 1 , wherein said dielectric lens is annular-shaped.
5. The antenna of claim 1 , wherein said dielectric lens comprises an alignment spacer, which extends between the inner and outer waveguides.
6. The antenna of claim 5 , wherein the alignment spacer is annular-shaped.
7. The antenna of claim 1 , wherein said dielectric lens comprises an annular-shaped alignment spacer, which extends between an outer surface of the inner waveguide and an inner surface of the outer waveguide.
8. The antenna of claim 7 , wherein a first portion of the dielectric block is matingly received within a distal end of the inner waveguide; and wherein said dielectric lens surrounds the first portion of the dielectric block.
9. The antenna of claim 1 , wherein said dielectric lens comprises a cross-linked polystyrene material.
10. The antenna of claim 1 , wherein the outer waveguide is cylindrically shaped and comprises an outwardly projecting and annular-shaped shoulder at its distal end.
11. A parabolic reflector antenna, comprising:
a dish reflector;
a feed boom waveguide having a proximal end coupled to said dish reflector;
a sub-reflector assembly comprising a dielectric block coupled to a distal end of said feed boom waveguide and a sub-reflector adjacent a distal end of the dielectric block; and
a dielectric lens on said feed boom waveguide at a location intermediate the proximal and distal ends thereof;
wherein said feed boom waveguide comprises inner and outer waveguides in coaxial alignment; and wherein said dielectric lens surrounds a portion of the inner waveguide.
12. A microwave antenna subassembly, comprising:
a dual-band waveguide;
a dielectric lens on a portion of said dual-band waveguide; and
a sub-reflector assembly coupled to a distal end of said dual-band waveguide;
wherein said dual-band waveguide comprises inner and outer waveguides in coaxial alignment; and wherein said dielectric lens surrounds a portion of the inner waveguide located adjacent the distal end.
13. The subassembly of claim 12 , wherein said dielectric lens and the inner waveguide are in coaxial alignment.
14. The subassembly of claim 12 , wherein said dielectric lens comprises an annular-shaped alignment spacer, which extends between the inner and outer waveguides.
15. The sub-assembly of claim 12 , wherein said sub-reflector assembly comprises a dielectric block coupled to the distal end of said dual-band waveguide and a sub-reflector adjacent a distal end of the dielectric block; and wherein a maximum outer diameter of said dielectric lens is greater than a maximum outer diameter of the dielectric block.
16. The sub-assembly of claim 15 , wherein a first portion of the dielectric block is matingly received within a distal end of the inner waveguide; and wherein said dielectric lens surrounds the first portion of the dielectric block.