Coincident transmit-receive beams plus conical scanned monopulse receive beam

• US 6,680,711 B2
• Filed: 07/09/2002
• Issued: 01/20/2004
• Est. Priority Date: 01/08/2002
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Desargant, Glen J., Bien, Albert L.
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US10/191,820
• Publication Number:
  US 20030128169A1
• Time in Patent Office: 560 Days
• Field of Search: H01/Q 1.300, 343/781.CA, 343/781.P, 343/909, 343/781.R, 343/782, 343/761
• US Class Current: 343/781.0CA
• CPC Class Codes: H01Q 15/0013 said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
• CPC Class Codes: H01Q 19/19 comprising one main concave reflecting surface associated with an auxiliary reflecting surface
• CPC Class Codes: H01Q 19/195 wherein a reflecting surface acts also as a polarisation filter or a polarising device
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 3/10 to produce a conical or spiral scan
• CPC Class Codes: H01Q 3/20 wherein the primary active element is fixed and the reflecting device is movable
• CPC Class Codes: H01Q 5/40 Imbricated or interleaved structures; Combined or electromagnetically coupled arrangements, e.g. comprising two or more non-connected fed radiating elements

Abstract

An antenna system includes a feedhorn, main reflector, sub-reflector, and frequency selective member. The sub-reflector includes an axially symmetrical reflecting surface. The frequency selective member includes an axially non-symmetrical reflecting surface. The frequency selective member transmits signals having a first frequency from the feedhorn to the sub-reflector. These signals are symmetrically reflected by the sub-reflector to the main reflector. The frequency selective member reflects signals having a second frequency from the main reflector to the feedhorn. These signals are reflected at a small conical angle by the frequency selective member to the feedhorn. In this way, the present transmit/receive system provides coincident transmit and receive signals with only conically scanned receive signals.

Claims

1. An antenna comprising:

a main reflector;

a feedhorn proximate said main reflector;

a sub-reflector mounted in signal communicating relation relative to said main reflector and said feedhorn, said sub-reflector including a symmetrical reflecting surface; and

a frequency selective member mounted in signal communicating relation relative to said main reflector and said feedhorn, said frequency selective member including a non-symmetrical reflecting surface.

2. The antenna of claim 1 wherein said frequency selective member is rotatable about a line of sight axis of said main reflector.

3. The antenna of claim 1 wherein said feedhorn and main reflector are disposed on one side of said frequency selective member and said sub-reflector is disposed on another side of said frequency selective member, said frequency selective member being adapted to pass a first signal from said feedhorn to said sub-reflector and reflect a second signal from said main reflector to said feedhorn.

4. The antenna of claim 3 wherein said first signal has a frequency of about 14 to about 14.5 GHz.

5. The antenna of claim 3 wherein the second signal has a frequency of about 11.2 to about 12.7 GHz.

6. The antenna of claim 3 wherein said first signal has a frequency of about 14 to about 14.5 GHz and said second signal has a frequency of about 11.2 to about 12.7 GHz.

7. The antenna of claim 1 wherein said frequency selective member is mounted to said sub-reflector.

8. The antenna of claim 7 wherein said frequency selective member and said sub-reflector are rotatable.

9. An antenna system comprising:

a main reflector having an active surface;

a sub-reflector spaced apart from said main reflector, a reflecting surface of said sub-reflector being symmetrical relative to a line of sight axis of said active surface of said main reflector; and

a frequency selective member rotatably disposed between said active surface of said main reflector and said symmetrical reflecting surface of said sub-reflector, a reflecting surface of said frequency selective member being non-symmetrical relative to said line of sight axis and coaxially aligned with said symmetrical reflecting surface of said sub-reflector.

10. The antenna system of claim 9 wherein said frequency selective member is coupled to said sub-reflector.

11. The antenna system of claim 9 further comprising a motor rotatably coupled to said frequency selective member.

12. The antenna system of claim 9 further comprising a feed horn disposed in a signal transmitting and receiving relation relative to said frequency selective member and said sub-reflector.

13. The antenna system of claim 9 wherein said frequency selective member further comprises a diplexer.

14. The antenna system of claim 9 wherein said frequency selective member further comprises a material adapted to transmit a first signal to said symmetrical reflecting surface of said sub-reflector and to reflect a second signal from said non-symmetrical reflecting surface.

15. The antenna system of claim 14 wherein said first signal further comprises a transmit signal from a feed horn and said second signal further comprises a receive signal from a satellite.

16. An antenna system comprising:

a main reflector having a line of sight axis;

a feedhorn aligned along said axis;

a sub-reflector spaced apart from said feedhorn and said main reflector, said sub-reflector having a reflecting surface symmetrically aligned relative to said axis;

a frequency selective member coupled to said sub-reflector facing said main reflector and said feedhorn, said frequency selective member having a reflecting surface non-symmetrically aligned relative to said axis; and

a motor rotatably coupled to said sub-reflector and said frequency selective member.

17. The antenna system of claim 16 wherein said frequency selective member further comprises a material adapted to transmit a first signal to said symmetrical reflecting surface of said sub-reflector and to reflect a second signal from said non-symmetrical reflecting surface.

18. The antenna system of claim 17 wherein said first signal further comprises a transmit signal from said feed horn and said second signal further comprises a receive signal from said main reflector.

19. A method of transmitting and receiving signals in an antenna comprising:

a transmitting step including;

feeding a transmit signal from a feed horn to a frequency selective member having a rotating non-symmetric reflecting surface;

passing the transmit signal through the rotating non-symmetric reflecting surface of the frequency selective member to a sub-reflector having a symmetric reflecting surface;

reflecting the transmit signal from the symmetric reflecting surface of the sub-reflector to a main reflector; and

reflecting the transmit signal from the main reflector to a desired satellite; and

a receiving step including;

receiving a receive signal from the desired satellite at the main reflector;

reflecting the receive signal from the main reflector to the rotating non-symmetrical reflecting surface of the frequency selective member; and

reflecting the receive signal from the rotating non-symmetric reflecting surface of the frequency selective member to the feed horn.

20. The method of claim 19 further comprising rotating the sub-reflector with the rotating non-symmetric reflecting surface of the frequency selective member.