Flat antenna for satellite communication

Abstract

A flat antenna for satellite communication includes a radiating board. The radiating board includes at least one radiating line, and an adapter configured to modify the delay of the fields transmitted or received by the radiating line. The adapter includes a horn mobile in rotation between the two metal plates containing a sensor array. The horn is also mobile in rotation between at least one coaxial cable connected between at least one sensor of the network and the radiating line. The length of the coaxial cable is suitable for introducing a delay required to focus the wave radiated by the radiating line.

Claims

1. A flat antenna for satellite telecommunication, comprising: a radiating board comprising at least one radiating line; and an adapter configured to modify a delay of fields emitted or received by said at least one radiating line, the adapter comprises: a horn movable in rotation between two metallic plates comprising an array of sensors, and between at least one sensor of the array and said at least one radiating line; and a length of said at least one coaxial cable is configured to introduce a delay required to focus a wave radiated by said at least one radiating line.

2. The flat antenna as claimed in claim 1, wherein the horn transmits the wave between the two metallic plates, an electric field of the wave is perpendicular to the metallic plates.

3. The flat antenna as claimed in claim 2, wherein the adapter further comprises an array of sensor monopoles fixed on at least one metallic plate; and wherein said at least one coaxial cable is connected between the array of sensor monopoles and said at least one radiating line.

4. The flat antenna as claimed in claim 1, wherein the adapter further comprises an array of sensor monopoles fixed on at least one metallic plate; and wherein said at least one coaxial cable is connected between the array of sensor monopoles and said at least one radiating line.

5. The flat antenna as claimed in claim 4, wherein the array of sensor monopoles comprises a surface closed by a metallic reflector.

6. The flat antenna as claimed in claim 5, wherein the metallic reflector is positioned at of a wavelength from the array of sensor monopoles.

7. The flat antenna as claimed in claim 1, wherein the length of said at least one coaxial cable is configured to introduce an additional delay to obtain an initial fixed pointing such that a total pointing varies from 0 to 60 for a symmetric displacement of the horn.

8. The flat antenna as claimed in claim 1, wherein the two metallic plates are fixed on a plane parallel to a plane of the radiating board.

9. The flat antenna as claimed in claim 1, wherein the radiating board comprises a plurality of radiating lines spaced apart by a half of a wavelength.

10. The flat antenna as claimed in claim 1, wherein the radiating board comprises a plurality of radiating lines comprising an alignment of radiating elements.

11. The flat antenna as claimed in claim 10, wherein the radiating elements are dipoles, patches or slots.

12. The flat antenna as claimed in claim 10, wherein each radiating line comprises a distributor with one input and a plurality of outputs corresponding to a number of the radiating elements of said each radiating line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood with the aid of the description, given hereinafter purely by way of explanation, of the embodiments of the invention, with reference to the figures in which:

(2) FIG. 1 illustrates a flat and movable satellite telecommunications antenna according to the prior art;

(3) FIG. 2 illustrates a flat satellite telecommunications antenna according to an embodiment of the invention; and

(4) FIG. 3 illustrates the movable horn of the antenna of FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION

(5) FIG. 2 reveals a flat satellite telecommunications antenna 10 consisting of a radiating board 16 linked to an adaptation means 11 able to modify the delays of the fields emitted or received by the radiating board 16.

(6) The radiating board 16 extends in a plane xy and comprises several radiating lines 17 disposed along the axis y at a spacing of about half a wavelength along the axis x. Each radiating line 17 consists of an alignment of N radiating elements (not represented), for example dipoles, patches or slots disposed at a spacing of less than a wavelength along the y axis and fed by a distributor comprising one input and N outputs.

(7) The adaptation means 11 consists of a horn 12 movable in rotation between two metallic plates 13a and 13b parallel to the radiating board 16. The horn 12, represented in FIG. 3, is movable in rotation about the axis z (parallel to or coincident with the axis z) extending in a direction normal to the plane xy. The mobility of the horn 12 is ensured by a numerically controlled guide 20.

(8) The horn 12 radiates between the two metallic plates 13a, 13b a TEM (for transverse electric-magnetic) wave whose electric field is perpendicular to the metallic plates 13a, 13b. An array of monopoles 14 is fixed on the upper metallic plate 13a in order to capture the TEM wave. The rear of the array of monopoles 14 is closed by a metallic reflector 15 situated at about of a wavelength in order to close the adaptation means.

(9) Each monopole of the array 14 is connected to each radiating line 17 of the radiating board 16 by way of a coaxial cable 18. The coaxial cables 18 are all of different lengths and introduce the delay required for focusing wave radiated by the radiating board 16. They also introduce an additional delay making it possible to obtain an initial fixed pointing in such a way that the total pointing varies from 0 to 60 for a symmetric displacement of the horn.

(10) The invention thus makes it possible to point in all the directions contained in the cone of half-angle 60 centered on the axis z by rotating the horn 12 by around 30 about the axis z and by rotating the antenna assembly by 360 about the axis z. This antenna structure operates in a very broad band of frequencies since the movable horn 12 makes it possible to obtain frequency-independent pointing.