Communications: directive radio wave systems and devices (e.g. – Directive – Including a steerable array
Reexamination Certificate
1999-10-29
2001-07-31
Blum, Theodore M. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a steerable array
C342S157000, C455S282000, C343S758000
Reexamination Certificate
active
06268827
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to antenna systems and, more particularly, to antenna systems which are deployed in space.
BACKGROUND OF THE INVENTION
A communications satellite is an artificial satellite placed into orbit around earth to, among other things, facilitate communications on earth. Communications satellites normally include antenna systems, which typically receive information from and transmit information to various locations on earth.
Phased-array antenna systems, which are well-known, are one type of antenna system that has been used with communications satellites. A phased-array antenna system is comprised of a plurality of antenna elements which are suitably spaced relative to one another. The antenna system generates a radiation pattern having a shape and direction that is determined by the combination of the relative phases and amplitudes of the signals applied to the antenna elements. By varying the relative phases of the signals applied to the antenna elements, the antenna's direction of radiation may be steered.
Conventional phased-array antenna systems typically include a driver stage, a plurality of transmit/receive modules (“T/R modules”) and an RF feed network comprised of RF transmission lines. In addition, such antenna systems include a DC power wire harness having a plurality of DC power signal conductors and a digital command/telemetry signal wire harness having a plurality of command/telemetry signal conductors.
Thus, typically, in conventional phased-array antenna systems, each T/R module is electrically connected to the driver stage via (
1
) an RF transmission line, (
2
) a DC power signal conductor from the DC power wire harness and (
3
) a command/telemetry signal conductor from the digital command/telemetry signal wire harness. Both the DC power signal conductors and the command/telemetry signal conductors are typically several meters (or more) in length and require shielding, sheathing, connectors and connector back shells. Furthermore, both the DC power wire harness and the digital command/telemetry signal wire harness require mounting hardware. Thus, when a phased-array antenna system includes hundreds or more TIR modules, the complexity and weight of the system increases dramatically due to the presence of the DC power wire harness, digital command/telemetry signal wire harness and their respective conductors.
When communications satellites are deployed into space, costs associated with delivering spacecraft payloads into the earth's orbit are based on the payload's weight. Thus, there is a need to reduce the weight of antenna systems associated with communications satellites. In addition, because antenna deployment is one of the highest risk components of a space-based satellite mission, there is a need to reduce antenna deployment risks. Finally, there is a need to reduce antenna costs, including costs related to procurement, testing and installation.
SUMMARY OF THE INVENTION
The present invention is designed to overcome the aforementioned problems and meet the aforementioned, and other, needs.
It is an object of the present invention to reduce the weight of antenna systems associated with communications satellites.
It is another object of the invention to reduce antenna deployment risks.
It is yet another object of the invention to reduce antenna costs, including costs related to procurement, testing and installation.
In accordance with the objects of the invention, the present invention advantageously reduces the number of electrical connections made to each T/R module. More specifically, the present invention eliminates both the DC power wire harness and the digital command/telemetry wire harness (and their respective conductors), while still providing their associated signals from the driver stage to each T/R module. Even more specifically, when the antenna is in a first mode, DC power, command information and RF signals (
1
) are multiplexed via a multiplexer, (
2
) propagate along the RF transmission line and (
3
) are appropriately demultiplexed by a demultiplexer associated with each T/R module. Similarly, when the antenna is in a second mode, telemetry or operations-related data (including, e.g., status information) and RF signals (
1
) are multiplexed via a multiplexer, (
2
) propagate along the RF transmission line and (
3
) are appropriately demultiplexed by a demultiplexer at the driver stage.
By using the RF transmission lines associated with each T/R module to deliver (
1
) DC power, (
2
) command data and (
3
) RF signals in a first mode and to deliver (
1
) telemetry data and (
2
) RF signals in a second mode, the DC power and command/telemetry wire harnesses (and their respective conductors) may be eliminated. Thus, the overall weight of the antenna system may be reduced. Furthermore, deployment risks may be reduced since, in conventional systems, both the DC power wire harness and command/telemetry wire harness (and their respective conductors) may inhibit deployment mechanisms. Finally, the overall cost of the antenna system may be reduced since the components required to implement the multiplexer/demultiplexer circuits can be realized in inexpensive, silicon integrated circuits (or alternatively in discrete form) placed in each T/R module and in the driver stage. In contrast, there is relatively greater expense in procuring, testing and installing conventional wire harnesses and connecting them from the driver stage to each T/R module via DC power signal conductors and command/telemetry signal conductors.
Other objects, features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.
REFERENCES:
patent: 3150374 (1964-09-01), Sunstein et al.
patent: 4881222 (1989-11-01), Goeckler et al.
patent: 4901310 (1990-02-01), Ichiyoshi
patent: 5220557 (1993-06-01), Kelley
patent: 5276920 (1994-01-01), Kuisma
patent: 5553079 (1996-09-01), Niki et al.
patent: 5634191 (1997-05-01), Beasley
patent: 5657358 (1997-08-01), Panech et al.
patent: 5687194 (1997-11-01), Paneth et al.
patent: 5751700 (1998-05-01), Imaeda
patent: 5821901 (1998-10-01), Zagrodnick et al.
patent: 5987060 (1999-11-01), Grenon et al.
Becker Dan
Burlingame Paul
Paschen Dean
Rait Gary
Ball Aerospace & Technologies Corp.
Blum Theodore M.
Ross P.C. Sheridan
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