Directional mobile antenna with polarization switching by displacement of radiating panels
An antenna with polarization switching comprises a support comprising at least two faces each supporting a plurality of waveguides fed with radiofrequency signals and pierced with apertures disposed so as to illuminate radiating elements placed some distance from the said apertures. For at least one given antenna pointing, the said support is able to toggle between at least two different configurations, the said support being configured so as to place, in the second configuration, the second face in a position identical to that taken by the first face in the first configuration, several radiating elements of the first face being, in the said position, oriented differently from radiating elements of the second face. It applies notably to the switching of antennas embedded onboard moving objects on the ground having to operate high-speed communications with a satellite, in particular a geostationary satellite.
1. A tracking antenna with polarization switching, comprising:
a support comprising at least two faces each supporting a plurality of waveguides fed with radiofrequency signals and pierced with apertures disposed so as to illuminate radiating elements placed some distance from the said apertures, wherein, for at least one given antenna pointing, said support is able to toggle between at least two different configurations, said support being configured so as to place, in the second configuration, the second face in a position identical to that taken by the first face in the first configuration, several radiating elements of the first face being, in said position, oriented differently from radiating elements of the second face.
2. The antenna with polarization switching according to claim 1 , in which the support is fixed on a swivel axis suitable for toggling between the two configurations by rotation.
3. The antenna with polarization switching according to claim 2 , in which the swivel axis is configured so that the respective positions of the first and of the second face of the support are mutually substituted after rotation of the support by half a revolution about the said axis.
4. The antenna with polarization switching according to claim 2 , in which the swivel axis is parallel to each of the faces.
5. The antenna with polarization switching according to claim 2 , in which the swivel axis, being the first swivel axis, is mounted on a second swivel axis orthogonal to the said first swivel axis.
6. The antenna with polarization switching according to claim 1 , in which the radiating elements are dipoles.
7. The antenna with polarization switching according to claim 6 , in which the dipoles of one and the same face are all oriented in the same direction.
8. The antenna with polarization switching according to claim 1 , in which the first face comprises a number of radiating elements equal to the number of radiating elements present on the second face, the radiating elements being disposed on each of the faces so that to each radiating element of the first face there corresponds a radiating element of the second face whose barycentre in the second configuration is identical to the barycentre of the corresponding radiating element of the first face when it is in the first configuration.
9. The antenna with polarization switching according to claim 1 , in which the waveguides are guides with rectangular cross-section, the apertures being distributed, for each of the waveguides, on a face of the said waveguide alternately on either side of its longitudinal median axis.
10. The antenna with polarization switching according to claim 1 , in which for two adjacent apertures of a waveguide, a radiating element is placed above each of the apertures.
11. A method of tracking a target using a tracking antenna with polarization switching, the antenna comprising:
a support including at least a first face and a second face that respectively support a plurality of waveguides fed with radiofrequency signals and are pierced with apertures disposed so as to illuminate radiating elements placed a distance from the apertures, wherein, for at least one antenna pointing, the support is configured to toggle between at least a first configuration and a second configuration, the support being configured so as to place, in the second configuration, the second face in a position that the first face is placed in the first configuration, several radiating elements of the first face being, in said position, oriented differently from radiating elements of the second face;
the method comprising:
pointing the first face toward a target, the support being in the first configuration;
tracking the target with the first face while maintaining the support in the first configuration;
toggling the support to be in the second configuration so that the second face takes the place of the first face; and
continuing tracking the target with the second face while maintaining the support in the second configuration.