Beam waveguide including Mizuguchi condition reflector sets

• US 7,786,945 B2
• Filed: 02/26/2007
• Issued: 08/31/2010
• Est. Priority Date: 02/26/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Werntz, Paul C., Hikido, Tom M., Tzelepis, Christ P., Baldauf, John E.
• Primary Examiner(s): Nguyen; Hoang V
• Assistant Examiner(s): Karacsony; Robert
• Application Number:
  US11/678,651
• Publication Number:
  US 20080204341A1
• Time in Patent Office: 1,282 Days
• Field of Search: 343/878, 343/879, 343/880, 343/882, 343/772, 343/781.R, 343/781.P, 343/781.CA, 343/757, 343/761, 343/762, 342/359
• US Class Current: 343/781.00P
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 19/191 wherein the primary active element uses one or more deflecting surfaces, e.g. beam waveguide feeds
• CPC Class Codes: H01Q 3/20 wherein the primary active element is fixed and the reflecting device is movable

Abstract

A beam waveguide may include a first set of dual offset reflectors and a second set of dual offset reflectors. The first set of dual offset reflectors and the second set of dual offset reflectors may each include reflector geometries to produce a radiation pattern that is symmetric about a first axis between the first and second set of dual offset reflectors and to produce an axi-symmetric beam from the second set of dual offset reflectors that is unaffected by any rotation of the first and second set of dual offset reflectors relative to one another about the first axis.

Claims

1. A beam waveguide, comprising:

a first set of dual offset reflectors;

a second set of dual offset reflectors, wherein the first set of dual offset reflectors and the second set of dual offset reflectors each include reflector geometries to produce a radiation pattern that is symmetric about a first axis between the first and second set of dual offset reflectors and to produce an axi-symmetric beam from the second set of dual offset reflectors that is unaffected by any rotation of the first and second set of dual offset reflectors relative to one another about the first axis;

a waveguide structure containing the first and second set of dual offset reflectors;

a first reflector to transmit or receive a beam along a second axis from the second set of dual offset reflectors, wherein the first flat reflector is rotatable relative to the second set of dual offset reflectors about the second axis;

a second reflector to transmit or receive the beam from the first reflector along a third axis and wherein the second reflector is rotatable relative to the first reflector about a third axis;

a first gimbal associated with the first axis for rotating the second set of dual offset reflectors to any angle relative to the first set of dual offset reflectors;

a second gimbal associated with the second axis for rotating the first reflector to any angle relative to the second set of dual offset reflectors; and

a third gimbal associated with the third axis to rotate the second reflector to any angle relative to the first reflector, the first gimbal, the second gimbal and the third gimbal being able to rotate the associated reflectors to any angle about the first axis, the second axis and the third axis to prevent any keyhole condition and to avoid any interference with the waveguide structure.

2. The beam waveguide of claim 1, wherein the first set of dual offset reflectors comprises:

one of a hyperboloid reflector or an ellipsoid reflector to receive a spherical wave; and

a paraboloid reflector to transmit a axi-symmetric collimated wave, that is axi-symmetrical about the first axis, to the second set of dual offset reflectors along the first axis, the first set of dual offset reflectors converting the received spherical wave to the axi-symmetric collimated wave, and wherein the second set of dual offset reflectors comprises;

a paraboloid reflector to receive the axi-symmetric collimated wave from the paraboloid reflector of the first set of dual offset reflectors, the first axis extending between the paraboloid of the first set of dual offset reflectors and the paraboloid of the second set of dual offset reflectors; and

one of a hyperboloid reflector or an ellipsoid reflector to produce an axi-symmetric spherical wave converted from the axi-symmetric collimated wave by the second set of dual offset reflectors.

3. The beam waveguide of claim 1, wherein the first set of dual offset reflectors and the second set of dual offset reflectors are rotatable relative to one another about the first axis without causing distortion to the axi-symmetrical spherical wave from the second set of dual offset reflectors.

4. The beam waveguide of claim 1, wherein the first set of dual offset reflectors and the second set of dual offset reflectors satisfy a Mizuguchi condition.

5. The beam waveguide of claim 1, wherein the reflector geometries of the first set of dual offset reflectors and the second set of dual offset reflectors are adapted to permit rotation of the first and second dual offset reflectors relative to one another about the first axis without causing distortion of an output beam and loss in antenna efficiency.

6. The beam waveguide of claim 1, wherein the first and second set of dual offset reflectors each comprise a different focal characteristic.

7. The beam waveguide of claim 1, wherein the first and second set of dual offset reflectors and the at least one reflector are adapted to produce a collimated beam from an aperture of an axi-symmetric Cassegrain reflector set that remains unchanged in response to any combination of rotational positions of the reflectors about the first, second and third axes to provide an unobstructed field of regard.

8. The beam waveguide of claim 1, wherein the first gimbal rotates the second gimbal, the third gimbal, the second set of dual offset reflectors and the first and second flat reflectors, and the second gimbal rotates the third gimbal and the first and second flat reflectors.

24. The beam waveguide of claim 8, further comprising a feed, wherein the feed and a first and second reflector of the first set of dual offset reflectors are fixedly mounted relative to one another.

9. A beam waveguide, comprising:

a first set of reflectors for receiving a spherical wave and collimating the wave axi-symmetrically about a first axis;

a second set of reflectors for receiving the axi-symmetric collimated wave transmitted along the first axis from the first set of reflectors, the second set of reflectors being adapted to convert the collimated wave back to an axi-symmetric spherical wave axi-symmetric about a second axis;

a waveguide structure containing the first and second set of reflectors;

a first reflector to transmit or receive a beam along a second axis from the second set of reflectors, wherein the first reflector is rotatable relative to the second set of reflectors about the second axis;

a second reflector to transmit or receive the beam from the first reflector along a third axis and wherein the second reflector is rotatable relative to the first reflector about a third axis;

a first gimbal associated with the first axis for rotating the second set of reflectors to any angle relative to the first set of dual reflectors;

a second gimbal associated with the second axis for rotating the first reflector to any angle relative to the second set of reflectors; and

a third gimbal associated with the third axis to rotate the second flat reflector to any angle relative to the first reflector, the first gimbal, the second gimbal and the third gimbal being able to rotate the associated reflectors to any angle about the first axis, the second axis and the third axis to prevent any keyhole condition and to avoid any interference with the waveguide structure.

10. The beam waveguide of claim 9, wherein one of the first set of reflectors and the second set of reflectors comprises reflector component geometries that permit the first and second set of reflectors to be rotated relative to one another about the first axis without affecting the axi-symmetric spherical wave.

11. The beam waveguide of claim 9, wherein the first set of reflectors comprises:

one of a hyperboloid reflector or an ellipsoid reflector to receive the spherical wave; and

a paraboloid reflector to transmit the axi-symmetric collimated wave along the first axis to the second set of dual offset reflectors, and wherein the second set of reflectors comprises;

a paraboloid reflector to receive the axi-symmetric collimated wave from the paraboloid of the first set of dual offset reflectors; and

one of a hyperboloid reflector or an ellipsoid reflector to transmit the axi symmetric spherical wave to the at least one reflector.

12. The beam waveguide of claim 9, wherein the third reflector is rotatable about a third axis and wherein the first and second set of reflectors and the first reflector are rotatable to any angular position about the first, second and third axes without affecting the axi-symmetrical spherical wave directed to the antenna.

13. The beam waveguide of claim 9, wherein the first set of reflectors and the second set of reflectors each comprise a dual offset reflector set that satisfy a Mizuguchi condition.

14. An antenna system, further comprising:

an antenna for transmitting an output wave;

a feed horn;

a first set of reflectors for receiving and converting a spherical wave from the feed horn to a collimated wave;

a second set of reflectors for receiving the collimated wave along a first axis from the first set of reflectors and converting the collimated wave to another spherical wave for transmission to the antenna, wherein at least one of the first and second set of reflectors are rotatable about the first axis and include reflector components to permit rotation about the first axis without affecting the output wave from the antenna;

a waveguide structure containing the first and second set of reflectors;

a first reflector to transmit or receive a beam along a second axis from the second set of reflectors, wherein the first reflector is rotatable relative to the second set of reflectors about the second axis;

a second reflector to transmit or receive the beam from the first reflector along a third axis and wherein the second reflector is rotatable relative to the first reflector about a third axis;

a first gimbal associated with the first axis for rotating the second set of reflectors to any angle relative to the first set of reflectors;

a second gimbal associated with the second axis for rotating the first reflector to any angle relative to the second set of reflectors; and

a third gimbal associated with the third axis to rotated the second reflector to any angle relative to the first reflector, the first gimbal, the second gimbal and the third gimbal being able to rotate the associated reflectors to any angle about the first axis, the second axis and the third axis to prevent any keyhole condition and to avoid any interference with the waveguide structure.

15. The antenna system of claim 14, wherein the first set of reflectors comprises a first set of dual offset reflectors for receiving and converting the spherical wave to an axi-symmetric collimated wave axi-symmetrical about the first axis, and the second set of reflectors comprises a second set of dual offset reflectors for receiving and converting the axi-symmetric collimated wave to an axi-symmetric spherical wave axi-symmetrical about the second axis.

16. The antenna system of claim 14, wherein the first and second set of reflectors satisfy a Mizuguchi condition.

17. The antenna system of claim 14, wherein the first set of reflectors comprises:

one of a hyperboloid reflector or an ellipsoid reflector to receive the spherical wave; and

a paraboloid reflector to transmit an axi-symmetric collimated wave along the first axis to the second set of reflectors, and wherein the second set of reflectors comprises;

a paraboloid reflector to receive the axi-symmetric collimated wave from the paraboloid of the first set of dual offset reflectors; and

one of a hyperboloid reflector or an ellipsoid reflector to transmit an axi-symmetric spherical wave converted from the axi-symmetric collimated wave to the antenna, wherein the axi-symmetric spherical wave is symmetric about a second axis.

18. The antenna system of claim 14, wherein the first and second set of reflectors and the first and second reflectors are configured to produce a beam from the antenna that is unchanged in response to any combination of rotational positions of the reflectors about the first, second and third axes to provide an unobstructed field of regard.

19. The antenna system of claim 14, wherein the antenna comprise an axi-symmetric Cassegrain reflector set and wherein the first and second set of reflectors comprise reflector elements to produce a collimated axi-symmetric beam from an aperture of the antenna that remains unchanged and undistorted in response to any rotation about the first axis.

20. The antenna system of claim 14, further comprising a waveguide, wherein at least the first and second set of reflectors are mounted in the waveguide, and wherein the waveguide, feed horn and antenna are mountable to a vehicle.

21. The antenna system of claim 14, wherein the antenna is adapted to receive a wave and the first and second set of reflectors are adapted to transmit the wave to the feed horn without affecting the wave regardless of a rotated position of the first and second set of reflectors about the first axis.

22. A method to provide a substantially complete field of regard in a beam waveguide without distortion in an output beam, comprising:

producing a collimated wave from a spherical wave for transmission along a first axis, within a waveguide structure, wherein the collimated wave is axi-symmetric to the first axis; and

producing an axi-symmetric spherical wave from the collimated axi-symmetric wave for transmission along a second axis within the waveguide structure, wherein the collimated wave remains axi-symmetrical and distortionless regardless of any rotation of reflector elements about the first and second axis; and

providing a third axis of rotation to provide the substantially complete field of regard, wherein the axi-symmetrical spherical wave remains unchanged and distortionless in response to the beam waveguide being any rotation position about the first, second and third axes to prevent any keyhole condition and to avoid any interference with the waveguide structure.

23. The method of claim 22, wherein producing the collimated wave from the spherical wave-and producing the axi-symmetrical spherical wave from the collimated axi-symmetric wave comprising providing a pair of Mizuguchi condition dual offset reflector sets.