Transponder with selective antenna beam using shared antenna feed elements

• US 4,956,643 A
• Filed: 05/02/1989
• Issued: 09/11/1990
• Est. Priority Date: 05/02/1989
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: HAC
• Inventors: Hahn, Carl J. III, Berman, Arnold L.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Hellner, Mark
• Application Number:
  US07/346,105
• Time in Patent Office: 497 Days
• Field of Search: 342/368, 342/51, 455/12, 455/13
• US Class Current: 342/51
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

A transponder that selectively provides both global and spot beam antenna coverage. The transponder comprises a channel amplifier and an antenna feed network that includes coupler means for coupling energy into a plurality of power distribution networks that feed a plurality of antenna radiating elements that form a beam that illuminates the desired coverage area. A variable power divider is coupled to the amplifier that variably couples power along two channel output paths. Each output path includes a matched bandpass filter and the second output path includes a phase delay circuit. Selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the total power provided by the channel amplifier to either the full set, or a selected subset of the antenna elements which generates global and spot beams, respectively. A more complex version is described which additionally incorporates an N-channel multiplexer. The present invention may also be employed as an interface circuit that may be interposed between a transponder channel amplifier and an antenna feed network to retrofit existing transponders to provide for selectable beam coverage.

Claims

1. A transponder comprising:

amplifier means for amplifying signal energy;

a variable power divider coupled to the amplifier means for variably coupling power along two output paths;

phase delay means disposed in one output path; and

an antenna feed network comprising an energy distribution network and a plurality of antenna elements and coupler means coupled to the two output paths for selectively coupling energy to the plurality of antenna elements and to a selected subset of the plurality of antenna elements;

whereby selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the power provided by the transponder to either the plurality of antenna elements or the selected subset of antenna elements, which selective coupling generates first and second predetermined beams radiated by the selected antenna elements.

2. The transponder of claim 1 further comprising:

first and second matched bandpass filters disposed in the first and second output paths, respectively.

3. The transponder of claim 1 further comprising:

at least one nonselectable transponder channel comprising amplifier means for amplifying signal energy within a predetermined energy band; and

a multiplexer coupled to the selectable and nonselectable transponder channels for coupling power provided thereby to the antenna feed network along the first output path.

4. The transponder of claim 3 further comprising:

a bandpass filter disposed in the nonselectable transponder channel.

5. The transponder of claim 1 further comprising:

a plurality of nonselectable transponder channels, each transponder channel comprising amplifier means for amplifying signal energy within a predetermined energy band; and

a multiplexer coupled to each of the transponder channels and to the selectable transponder channel for coupling power provided thereby to the antenna feed network along the first output path.

6. A transponder comprising:

transponder amplifier means for amplifying signal energy within a predetermined energy band;

an antenna feed network comprising coupler means coupled to a plurality of power distribution networks that feed a plurality of antenna element arrays;

a variable power divider coupled to the transponder amplifier means for variably coupling power along two transponder output paths;

a bandpass filter disposed in the first output path and coupled between a first output of the variable power divider and a first input port of the coupler means of the antenna network;

a phase delay circuit and a bandpass filter disposed in the second output path and coupled between a second output of the variable power divider and a second input port of the coupler means of the antenna network;

whereby selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the power provided by the transponder to either one, or both, of the input ports, which selective coupling generates first and second predetermined beams provided by selected subsets of antenna elements of the antenna network.

7. The transponder of claim 6 further comprising:

a plurality of nonselectable transponder channels, each transponder channel comprising amplifier means for amplifying signal energy within a predetermined energy band; and

a multiplexer coupled to each of the transponder channels and to the selectable transponder channel for coupling power provided thereby to a first input port of the coupler means.

8. A circuit that interfaces between a single channel transponder amplifier and an antenna network, said circuit comprising:

a variable power divider device adapted to receive input power from the transponder amplifier;

a first output path coupled between a first output of the variable power divider and a first input port of coupler means to the antenna network;

a second output path comprising a phase delay circuit coupled between a second output of the variable power divider and a second input port of the coupler means to the antenna network;

whereby selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the total power provided by the transponder amplifier to all of the antenna elements or a selected subset thereof, which selective coupling generates global and spot beams, respectively.

9. A circuit that interfaces between a channel amplifier of a multi-channel transponder and an antenna network, said circuit comprising:

a variable power divider device adapted to receive input power from the channel amplifier;

a first output path coupling a first output of the variable power divider to an input of a selected channel filter of an output multiplexer that is coupled to a first input of coupler means to the antenna network;

a second output path comprising a phase delay circuit and a matching bandpass filter coupled between a second output of the variable power divider and a second input port of the coupler means to the antenna network;

whereby selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the power provided by the transponder channel amplifier to either one, or both, of the input ports of the coupler means to the antenna network, which selective coupling generates first and second predetermined beams provided by selected sets of antenna elements of the antenna network.

10. A circuit that selectively distributes power to a set of antenna elements of an antenna network and a selected subset of antenna elements thereof, said circuit comprising:

a variable power divider adapted to receive input power from a channel amplifier of a transponder;

a first output path comprising a bandpass filter coupled between a first output of the variable power divider and a first input port of coupler means to the antenna network;

a second output path comprising a phase delay circuit and a matching bandpass filter coupled between a second output of the variable power divider and a second input port of the coupler means to the antenna network;

whereby selective control of the ratio of the power coupled to the respective output paths, and the phase delay provided by the phase delay circuit, provides for selective coupling of the power provided by the channel amplifier to either the set of antenna elements or the selected subset of antenna elements, which selective coupling provides for first and second predetermined beams provided by respective ones of the selected sets of antenna elements.