Low-cost diplexed multiple beam integrated antenna system for LEO satellite constellation

• US 9,698,492 B2
• Filed: 01/28/2015
• Issued: 07/04/2017
• Est. Priority Date: 01/28/2015
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Inventors: Rao, Sudhakar K., Roper, Daniel H., Bhattacharyya, Arun K.
• Primary Examiner(s): Levi, Dameon E
• Assistant Examiner(s): Alkassim, Jr., Ab Salam
• Application Number:
  US14/608,070
• Publication Number:
  US 20160218436A1
• Time in Patent Office: 888 Days
• Field of Search: 343779, 343786, 343835
• CPC Class Codes: H01P 1/173 using a conductive element
• CPC Class Codes: H01P 1/2131 with combining or separating polarisations
• CPC Class Codes: H01P 1/2138 using hollow waveguide filters H01P1/2131 takes precedence
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 13/02 Waveguide horns
• CPC Class Codes: H01Q 13/0241 radiating a circularly polarised wave H01Q13/0258 takes precedence; polarisation converters H01Q15/244, in a waveguide H01P1/17
• CPC Class Codes: H01Q 15/244 converting a linear polarised wave into a circular polarised wave guided wave H01P1/17
• CPC Class Codes: H01Q 21/064 using horn or slot aerials slotted waveguides arrays H01Q21/005
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system

Abstract

A multiple beam integrated antenna system for a satellite including a support structure having an alignment plate. The antenna system further includes a plurality of feed horns mounted to the alignment plate, where each feed horn includes a plurality of tapered sections that support propagation modes for both up-link signals and down-link signals. A septum polarizer is mounted to an input end of each feed horn that converts linearly polarized signals to circularly polarized signals for the up-link signals and converts circularly polarized signals to linearly polarized signals for the down-link signals. A Y-shaped waveguide is coupled to each of the polarizers and includes separate receive reject and transmit reject filters so as to keep the up-link signals and the down-link signals from interfering with each other. Flex waveguides couple the transmit leg and the receive leg of each Y-shaped waveguide to RF modules.

Claims

1. An integrated antenna system for a satellite, said antenna system comprising:

a support structure including a base plate and a strut assembly mounted to the base plate and defining an enclosure, said support structure further including an alignment plate mounted to the strut assembly opposite to the base plate;

a plurality of feed horns mounted to the alignment plate in a rigid manner so that each feed horn has a predetermined pointing direction, each feed horn including a plurality of tapered sections defining transitions therebetween that support propagation modes for both up-link signals and down-link signals, each feed horn further including an input end and an aperture end, wherein a down-link frequency band for the down-link signals is separated into four separate frequency channels and an up-link frequency band for the up-link signals is separated into two separate frequency channels, where a plurality of the plurality of feed horns operate at the frequency for a particular frequency channel and where the feed horns operating at the same down-link frequency channel are not adjacent to each other;

a plurality of septum polarizers where a separate septum polarizer is coupled to the input end of each feed horn, each septum polarizer converting circularly polarized signals to linearly polarized signals for the up-link signals received by the feed horn and converting linearly polarized signals to circularly polarized signals for the down-link signals to be transmitted by the feed horn;

a Y-shaped waveguide including a polarizer port, a transmit leg and a receive leg, said polarizer port being coupled to the septum polarizer opposite to the feed horn, wherein the receive leg includes a transmit reject filter for selectively passing the up-link signals and rejecting the down-link signals and the transmit leg includes a receive reject filter for selectively passing the down-link signals and rejecting the up-link signals;

an RF circuit board mounted on the base plate within the enclosure and including a plurality of RF modules for processing the up-link and down-link signals; and

a plurality of flex waveguides where a separate flex waveguide is coupled to the receive leg of each Y-shaped waveguide and one of the RF modules and coupled to the transmit leg of each Y-shaped waveguide and one of the RF modules to direct the down-link signals from the RF module to the transmit leg and direct the up-link signals from the receive leg to the RF module.

2. The antenna system according to claim 1 wherein the mechanical support structure is a die-cast aluminum structure.

3. The antenna system according to claim 1 wherein the feed horn and the septum polarizer are a single formed piece.

4. The antenna system according to claim 1 wherein the feed horn, the septum polarizer and the waveguide filter are a single formed piece.

5. The antenna system according to claim 1 wherein the plurality of feed horns is nineteen feed horns.

6. The antenna system according to claim 1 wherein the down-link frequency band is 10.7-12.7 GHz and a first down-link frequency channel is 10.7-11.2 GHz, a second down-link frequency channel is 11.2-11.7 GHz, a third down-link frequency channel is 11.7-12.2 GHz, and a fourth down-link frequency channel is 12.2-12.7 GHz.

7. The antenna system according to claim 6 wherein the up-link frequency band includes a first up-link frequency channel at 12.75-13.25 and a second up-link frequency channel at 14.00-14.50.

8. The antenna system according to claim 7 wherein the feed horns that operate at the first, second and third down-link frequency channels also operate at the first up-link frequency channel and the fourth down-link frequency channel operates at the second up-link frequency channel.

9. The antenna system according to claim 7 wherein the feed horns that operate at the first down-link frequency channel also operate at the first up-link frequency channel and the feed horns that operate at the second, third and fourth down-link frequency channels also operate at the second up-link frequency channel.

10. The antenna system according to claim 1 wherein the antenna system is mounted on a low Earth orbit satellite.

11. A diplexed multiple beam integrated antenna system comprising:

a plurality of feed horns mounted to an alignment plate so that each feed horn has a predetermined pointing direction, each feed horn including a plurality of tapered sections defining transitions therebetween that support multiple propagation modes, each feed horn further including an input end and an aperture end;

a plurality of polarizers where a separate polarizer is coupled to the input end of each feed horn, each polarizer converting circularly polarized signals to linearly polarized signals for receive signals received by the feed horn and converting linearly polarized signals to circularly polarized signals for transmit signals to be transmitted by the feed horn, wherein a transmit frequency band for the transmit signals is separated into four separate frequency channels and a receive frequency band for the receive signals is separated into two separate frequency channels, where a plurality of the plurality of feed horns operate at the frequency for a particular frequency channel and where the feed horns operating at the same transmit frequency channel are not adjacent to each other;

a filter waveguide including a polarizer port, a transmit leg and a receive leg, where the transmit leg and the receive leg are isolated by more than 20 dB, said polarizer port being coupled to the polarizer opposite to the feed horn, wherein the receive leg includes a transmit reject filter for selectively passing the receive signals and rejecting the transmit signals and the transmit leg includes a receive reject filter for selectively passing the transmit signals and rejecting the receive signals;

an RF circuit board including a plurality of RF modules for processing the receive and transmit signals;

a plurality of flex waveguides where a separate flex waveguide is coupled to the receive leg of each filter waveguide and one of the RF modules and the transmit leg of each filter waveguide and one of the RF modules to direct the transmit signals from the RF module to the transmit leg and direct the receive signals from the receive leg to the RF module; and

a combination of a septum polarizer with isolated ports and the filters providing the desired isolation between the up-link and down-link RF signals.

12. The antenna system according to claim 11 wherein the feed horn and the polarizer are a single formed piece.

13. The antenna system according to claim 11 wherein the feed horn, the polarizer and the waveguide filter are a single formed piece.

14. The antenna system according to claim 11 wherein the plurality of feed horns is nineteen feed horns.

15. The antenna system according to claim 11 wherein the antenna system is mounted on a low Earth orbit satellite.

16. An integrated antenna system for a low earth orbit (LEO) satellite, said antenna system comprising:

a support structure including a base plate and a strut assembly mounted to the base plate and defining an enclosure, said support structure further including an alignment plate mounted to the strut assembly opposite to the base plate;

nineteen feed horns mounted to the alignment plate in a rigid manner so that each feed horn has a predetermined pointing direction, each feed horn including a plurality of tapered sections defining transitions therebetween that support propagation modes for both up-link signals and down-link signals, each feed horn further including an input end and an aperture end, wherein a down-link frequency band for the down-link signals is separated into four separate frequency channels and an up-link frequency band for the up-link signals is separated into two separate frequency channels, where a plurality of the feed horns operate at the frequency for a particular frequency channel and where the feed horns operating at the same down-link frequency channel are not adjacent to each other;

a plurality of septum polarizers where a separate septum polarizer is coupled to the input end of each feed horn, each septum polarizer converting linearly polarized signals to circularly polarized signals for the up-link signals received by the feed horn and converting circularly polarized signals to linearly polarized signals for the down-link signals to be transmitted by the feed horn;

a Y-shaped waveguide including a polarizer port, a transmit leg and a receive leg, said polarizer port being coupled to the septum polarizer opposite to the feed horn, wherein the receive leg includes a transmit reject filter for selectively passing the up-link signals and rejecting the down-link signals and the transmit leg includes a receive reject filter for selectively passing the down-link signals and rejecting the up-link signals;

an RF circuit board mounted on the base plate within the enclosure and including a plurality of RF modules for processing the up-link and down-link signals; and

a plurality of flex waveguides where a separate flex waveguide is coupled to the receive leg of each Y-shaped waveguide and one of the RF modules and coupled to the transmit leg of each Y-shaped waveguide and one of the RF modules to direct the down-link signals from the RF module to the transmit leg and direct the up-link signals from the receive leg to the RF module.

17. The antenna system according to claim 16 wherein the down-link frequency band is 10.7-12.7 GHz and a first down-link frequency channel is 10.7-11.2 GHz, a second down-link frequency channel is 11.2-11.7 GHz, a third down-link frequency channel is 11.7-12.2 GHz, and a fourth down-link frequency channel is 12.2-12.7 GHz, and the up-link frequency band includes a first up-link frequency channel at 12.75-13.25 and a second up-link frequency channel at 14.00-14.50.

18. The antenna system according to claim 17 wherein the feed horns that operate at the first down-link frequency channel also operate at the first up-link frequency channel and the feed horns that operate at the second, third and fourth down-link frequency channels also operate at the second up-link frequency channel.