Co-located multi-band antenna
View Patent ↗A multi-band reflector antenna having a main reflector, a sub reflector, a first feed and a second feed. The first feed, the sub reflector and the main reflector positioned in a Gregorian optic configuration wherein an output of the first feed is directed to the sub reflector, from the sub reflector to the main reflector and from the main reflector into a first beam. The sub reflector may be shaped to distribute the output of the first feed reflecting off the sub reflector onto the main reflector whereby a central area of the main reflector has a lower illumination than a surrounding outer area of the main reflector and or elongated vertically. The second feed projecting from a hole in the sub reflector is oriented whereby an output of the second feed is directed to the main reflector and from the main reflector into a second beam.
1. A multi-band reflector antenna, comprising:
a main reflector;
a sub reflector;
a first feed; and
a second feed projecting from a hole in the sub reflector;
the first feed, the sub reflector and the main reflector positioned in a Gregorian optic configuration wherein an output of the first feed is directed to the sub reflector, from the sub reflector to the main reflector and from the main reflector into a first beam;
the sub reflector shaped to distribute the output of the first feed reflecting off the sub reflector onto the main reflector, whereby a central area of the main reflector has a lower illumination than a surrounding outer area of the main reflector;
the second feed oriented whereby an output of the second feed is directed to the main reflector and from the main reflector into a second beam.
2. The antenna of claim 1 , wherein a phase center of the second feed is positioned proximate a focal region of the main reflector.
3. The antenna of claim 1 , wherein the second feed is disposed within the hole.
4. The antenna of claim 1 , wherein the second feed extends through the hole into a focal region of the main reflector.
5. The antenna of claim 1 , wherein the sub reflector is in an offset configuration with respect to the main reflector.
6. The antenna of claim 1 , wherein a reflective surface of the sub reflector is not frequency selective.
7. The antenna of claim 1 , wherein the second feed is one of a horn antenna, a polyrod antenna, a helix antenna and an antenna array.
8. The antenna of claim 1 , further including a primary third feed proximate the sub reflector.
9. The antenna of claim 8 , wherein the primary third feed has a minimum scan of greater than 3 degrees.
10. The antenna of claim 8 , wherein the primary third feed is positioned within a notch formed in the sub reflector.
11. The antenna of claim 10 , wherein the notch is configured via one of a numerically tabulated and an analytic function that varies a rim feed angle of the sub reflector.
12. The antenna of claim 8 , further including a secondary third feed adjacent the sub reflector on a side of the sub reflector opposite from the primary third feed.
13. The antenna of claim 8 , further including a secondary third feed adjacent the primary third feed.
14. The antenna of claim 1 , further including a third feed disposed in a second hole in the sub reflector, adjacent the second feed.
15. The antenna of claim 14 , wherein the third feed and the second feed are scanned apart by between 2 and 8 degrees.
16. The antenna of claim 1 , wherein the first beam and the second beam are nominally coincident with each other.
17. The antenna of claim 1 , wherein the first beam and the second beam are scanned apart by at least 2 degrees.
18. The antenna of claim 1 , wherein the second feed has a gain of 14 dBi or less.
19. The antenna of claim 1 , wherein the sub reflector is dimensioned to be at least 8 wavelengths of a midband frequency of the first feed.
20. The antenna of claim 1 , wherein the second feed is configured to simultaneously operate at two different frequency bands.
21. The antenna of claim 1 , further including a third feed disposed proximate the first feed.
22. The antenna of claim 21 , wherein the third feed is scanned away from the first feed between 2 and 8 degrees.
23. A multi-band reflector antenna, comprising:
a main reflector;
a sub reflector;
a first feed; and
a second feed projecting from a hole in the sub reflector;
the first feed, the sub reflector and the main reflector positioned in a Gregorian optic configuration wherein an output of the first feed is directed to the sub reflector, from the sub reflector to the main reflector and from the main reflector into a first beam;
the second feed oriented whereby an output of the second feed is directed to the main reflector and from the main reflector into a second beam;
the sub reflector shaped to have an elevation dimension that is greater than an azimuth dimension.
24. The antenna of claim 23 , wherein the second feed has a gain of more than 14 dBi.
25. The antenna of claim 23 , wherein the sub reflector is dimensioned to be less than 8 wavelengths of a midband frequency of the second radio frequency feed.
26. The antenna of claim 23 , wherein a phase center of the second feed is positioned proximate a focal region of the main reflector.
27. The antenna of claim 23 , wherein the second feed is disposed within the hole.
28. The antenna of claim 23 , wherein the second feed extends through the hole into a focal region of the main reflector.
29. The antenna of claim 23 , wherein the sub reflector is in an offset configuration with respect to the main reflector.
30. The antenna of claim 23 , wherein a reflective surface of the sub reflector is not frequency selective.
31. The antenna of claim 23 , wherein the second feed is one of a horn antenna, a polyrod antenna, a helix antenna and an antenna array.
32. The antenna of claim 23 , further including a primary third feed proximate the sub reflector.
33. The antenna of claim 32 , wherein the primary third feed has a scan of greater than 4 degrees.
34. The antenna of claim 32 , wherein the primary third feed is positioned within a notch formed in the sub reflector.
35. The antenna of claim 34 , wherein the notch is configured via one of a numerically tabulated and an analytic function that varies a rim feed angle of the sub reflector.
36. The antenna of claim 34 , further including a secondary third feed adjacent the sub reflector on a side of the sub reflector opposite from the primary third feed.
37. The antenna of claim 34 , further including a secondary third feed adjacent the primary third feed.
38. The antenna of claim 23 , further including a third feed disposed in the hole, adjacent the second feed.
39. The antenna of claim 23 , wherein the first beam and the second beam are nominally coincident with each other.
40. The antenna of claim 23 , wherein the first beam and the second beam are scanned apart by at least 2 degrees.
41. The antenna of claim 23 , wherein the second feed is configured to simultaneously operate at two different frequency bands.