Horn antenna with corrugated grating

Patent metadata

Field	Value
Publication number	US-9484637-B2
Application number	US-201313871195-A
Country	US
Kind code	B2
Filing date	Apr 26, 2013
Priority date	Apr 27, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A horn that radiates a radioelectric wave coming from an input waveguide, comprises a grating placed over the aperture of the horn. The waveguide comprises a horn-shaped segment, an entrance, an aperture, and a grating placed next to the aperture. It makes it possible for at least one linearly polarised electromagnetic wave to propagate between the entrance and the aperture along a first axis. The grating comprises a frame and a set of plates extending longitudinally and continuously from a first short side of the frame to a second short side of the frame, so as to form a linear polarising filter for any electromagnetic wave the electric field of which is not polarised along a second axis orthogonal to the first axis. The grating of the waveguide comprises corrugations to reinforce the filtering of the electromagnetic wave the electric field of which is not polarised along the second axis.

First claim

The invention claimed is:

1. A waveguide, comprising:
a horn-shaped segment,
an entrance,
an aperture, and
a grating placed next to the aperture, wherein the waveguide is configured to transmit at least one linearly polarised electromagnetic wave for propagation between the entrance and the aperture of the waveguide along a first axis, the grating comprising a frame encircling a set of plates extending longitudinally and continuously from a first short side of the frame to a second short side of the frame, to form a linear polarising filter attenuating a cross-polarisation component of the electric field of the electromagnetic wave, said cross-polarisation component being orthogonal to a second axis orthogonal to the first axis, each plate of the set of plates includes corrugations, depths of respective corrugations and intervals between adjacent corrugations along a direction in which the set of plates longitudinally extend being dimensioned and positioned to reinforce the attenuating of said cross-polarisation component,
wherein the corrugations are slits cut in a side opposite the entrance of the waveguide, each corrugation having a depth along the first axis and a width along the direction in which the set of plates longitudinally extend from the first short side to the second short side, the depths of respective corrugations and the intervals between respective adjacent corrugations along the direction in which the set of plates longitudinally extend being defined to reinforce the attenuating of said cross-polarisation component, widths of said respective corrugations being smaller relative to the intervals between the adjacent corrugations and relative to depths of said respective corrugations.

2. The waveguide according to claim 1 , in which the corrugations are rectangular slits cut in the side opposite the entrance of the waveguide.

3. The waveguide according to claim 1 , in which the corrugations have dimensions that vary depending on their position in the direction in which the plates extend longitudinally between the first and second short sides of the frame, as a function of the frequency of the electric field of the electromagnetic wave having locally the largest amplitude at the respective corrugations.

4. The waveguide according claim 2 , in which the depth of the slits is substantially equal to a quarter of the wavelength corresponding to the frequency of the electric field having locally the largest amplitude at the respective slits, and being essentially oriented along the second axis.

5. The waveguide-according to claim 2 , in which the depth of the slits is substantially equal to a quarter of the wavelength corresponding to a frequency of an operating frequency band of the waveguide, the electromagnetic wave emitted in said operating frequency band having an electric field essentially oriented along the second axis.

6. The waveguide according to claim 3 , in which the higher the frequency having locally the largest amplitude, the smaller the width of the slits.

7. The waveguide according to claim 1 , in which the interval between two adjacent corrugations in the direction in which the plates extend longitudinally is substantially equal to a quarter of the wavelength corresponding to the frequency of the electric field of the electromagnetic wave having locally the largest amplitude at the respective slits.

8. The waveguide according to claim 1 , in which the interval between two adjacent corrugations in the direction in which the plates extend longitudinally is substantially equal to a quarter of the wavelength corresponding to a frequency of an operating frequency band of the waveguide, the electromagnetic wave emitted in said operating frequency band having an electric field essentially oriented along the second axis.

9. The waveguide-according to claim 1 , in which the frame comprises corrugations.

10. The waveguide-according to claim 9 , in which the frame comprises corrugations extending right through the thickness of at least one side of the frame in a direction perpendicular to the first axis.

11. The waveguide according to claim 10 , in which the frame comprises corrugations extending right through the thickness of at least one side of the frame along the second axis and/or corrugations extending right through the thickness of at least one side of the frame along a third axis orthogonal to the first axis and to the second axis.

12. The waveguide according to claim 1 , in which the corrugations are aligned in sets along the second axis, the corrugations of a given set having identical dimensions.

13. The waveguide according to claim 1 , in which the plates extend longitudinally in a direction substantially parallel to a third axis orthogonal to the second axis and orthogonal to the first axis.

14. The waveguide according to claim 1 , in which the plates extend longitudinally in a direction making, with a third axis orthogonal to the second axis and orthogonal to the first axis, an angle between 0.05° and 5° about the first axis.

15. The waveguide according to claim 1 , in which the waveguide is designed to operate in an operating frequency band, the plates having a height along the z-axis substantially equal to half a wavelength corresponding to a frequency in the operating frequency band of the waveguide.

16. The waveguide according to claim 1 , in which the grating is placed at a non-zero distance away from the aperture of the waveguide along the first axis.

17. The waveguide according to claim 1 , comprising at least one additional grating, the gratings being spaced apart pairwise along the first axis by a distance ranging from the wavelength corresponding substantially to a central frequency of an operating frequency band of the waveguide, to one eighth of this wavelength.

18. The waveguide-according to claim 17 , in which one or more additional gratings are placed parallel to the grating placed next to the aperture.

19. The waveguide according to claim 17 , in which one or more additional gratings each comprise corrugations.

20. The waveguide-according to claim 17 , in which each additional grating is substantially identical to the grating placed next to the aperture.

21. A satellite antenna comprising a waveguide according to claim 1 .

22. The waveguide according to claim 1 , in which the interval between two adjacent corrugations in the direction in which the plates extend longitudinally is substantially equal to a half of the wavelength corresponding to the frequency of the electric field of the electromagnetic wave having locally the largest amplitude at the respective slits.

23. The waveguide according to claim 1 , in which the interval between two adjacent corrugations in the direction in which the plates extend longitudinally is substantially equal to a half of the wavelength corresponding to a frequency of an operating frequency band of the waveguide, the electromagnetic wave emitted in said operating frequency band having an electric field essentially oriented along the second axis.

24. The waveguide according to claim 1 , wherein heights of respective plates, intervals between respective adjacent plates and intervals between external plates and the internal edge of the frame are defined to form a linear polarising filter attenuating the cross-polarisation component of an electric field of the electromagnetic wave.

Assignees

• Thales Sa

Inventors

• Jardin Michael
• Labourdette Claude
• Judasz Thierry
• Benoist Bruno
• Martin Olivier

Classifications

• H01Q19/028

  for reducing the cross polarisation · CPC title

• H01Q13/02 Primary

  Waveguide horns · CPC title

• H01Q15/242 Primary

  Polarisation converters · CPC title

• H01Q15/24

  Polarising devices; Polarisation filters  (H01Q15/12, H01Q15/22 take precedence) · CPC title