FR2677813A1 - LOW-DIMENSIONAL ACTIVE ANTENNA FOR WEATHER SATELLITE. - Google Patents

Abstract

The subject of the invention is an active antenna with a small footprint for a geostationary meteorological satellite. Space-saving meteorological antenna characterized by the fact that it is housed in a protection (1) of low absorption plastic, it includes one or more antennas (2, 3) directives of the QUAGI type correctly phased with a mechanical gain of more than 15 Dbd, said antennas (2, 3) are activated and amplified by means of a low noise preamplifier (4) arranged at the input of the plastic shield (1) so as to be able to place the receiver at n ' No matter what distance from the weather antenna, the preamplifier (4) is supplied with direct current by a coaxial cable (5) which connects the weather antenna to the receiver. Weather satellite antenna for mobile or maritime installation.

Description

The subject of the invention is a weak active antenna.

  congestion for meteorological satellite.

  At present, the state of the art can be defined by the following patents: FR-A-2 627 330: the present invention relates to a multifrequency antenna comprising a first printed antenna operating at one or more frequencies, and a second antenna arranged in front of the first antenna using the same surface

  radiating and operating at a different frequency.

  Application particularly to the field of space telecommunications.

  FR-A-2,625,327: the radar, of the quasi-modulation type,

  linearly of the frequency of the signal emitted during the pulse, comprises a transmission channel provided with a high frequency oscillator, a transmitting-receiving antenna and a reception channel provided with a pulse compression member. In the transmission chain, an Impatt diode of a diode combiner directly generates a synchronization signal of the oscillator (pulses modulated according to negative frequency ramps) at microwave frequency. For this purpose, a clock generator control in conduction, for each pulse to be emitted, a switch arranged in series on the driver

  substantially constant current supply of the Impatt diode.

  Application to cartography or meteorology.

  FR-A-2 587 548: reflector comprising carrying branches articulated on a support spaced from the latter approximately radially in the deployed state, carrying a reflective network

  and pivotable upward for folding.

  Between neighboring supporting branches are arranged folding elements substantially transverse to them and fixed at preselectable intervals to the reflector network, the folding being effected by successive shortening of

  intervals between the attachment points.

  The invention applies in particular to antenna reflectors

Astronautics.

  FR-A-2 643 511: the antenna system for direct broadcast satellite reception consists of a parabolic reflector associated with source means, the reflector being positioned and held by means of a support foot formed of a hollow tubular body fixed in its upper part to the rear central area of the reflector and articulated at its lower part on a base around a horizontal axis to define the elevation of the antenna. The base comprises a rotatable portion for defining the azimuth of the antenna The tubular body of the support leg has a section sufficient to contain all the circuits associated with the antenna. Application, in particular, to the reception of satellites whose

  Radiated powers are greater than 50 d BW.

  FR-A-2 584 872: the field of the invention is that of antennas intended to receive and / or radiate the electromagnetic waves in circular polarization, produced by the

printed circuit technology.

  The problem solved is to allow the realization of a low cost antenna, broadband frequency, with a good performance, and the possibility of being used alone or in network. According to the invention, the antenna consists of at least one wire conductor or micro-ribbon so as to form a continuous cruciform circuit arranged parallel to a conductive plate

  from which it is separated by a dielectric layer.

  The invention finds a preferential application for the equipment of mobile land terminals with connection of

satellite communication.

  At present meteorological satellites known as METEOSAT and GOES send at a continuous rate photographs of the earth intended for meteorology, seen at 36500 km high on two radio channels at 1.691 and 1.694 GHZ. The signal is of weak power, it can not to be received only by specific antennas

  dishes of 1.2 meters in diameter or more.

  These specific antennas are not a problem for fixed installations, eg for installations

military or scientific.

  For use on boats, it is necessary that they already have a large size to accommodate

  such antennas with such dimensions.

  Increasingly, the use of weather information on mobile installations or on small units is felt It is therefore necessary to have a specific portable antenna or at least small footprint. The antenna according to the invention tends to solve all these problems. The antenna targets two applications, according to two embodiments. One is a portable antenna, the other is an antenna for

  a mobile maritime job on small units.

  In addition, the antenna according to the invention reduces the cost of

manufacture of this type of antenna.

  For this purpose, the small space weather antenna according to the invention is housed in a low absorption plastic cover, it comprises one or more QUAGI-type directional antennas correctly phased with a mechanical gain of more than 15 Dbd. , said antennas are activated and amplified by means of a low-noise preamplifier arranged at the entrance of the plastic protection so as to be able to place the receiver at any distance from the weather antenna, the preamplifier is powered in direct current through a coaxial cable that connects the antenna

weather at the receiver.

  According to another preferred embodiment, in the case of a mobile maritime application, the weather antenna is provided with a three-dimensional self-stabilizing device actuated by three servomotors, said antenna is housed in a low-level plastic protection device. absorption in the form of a ball or cylinder of small diameter whose base has a truncated cone shape, said base is fixed to the superstructure of the boat and electrically connected by a cable to the protective ball and

to the electricity grid.

  Two servomotors regulate the antenna according to the geographical position of the boat and the third servomotor is controlled by

an electronic compass.

  The attached drawings are given as indicative and nonlimiting examples. They represent a preferred embodiment according to the invention.

easily understand the invention.

  FIG. 1 is a schematic view of a weather antenna viewed in perspective showing the

  different elements that constitute said antenna.

  FIG. 2 is a schematic view of a weather antenna adapted to a maritime employment highlighting

  the antennas and the self-stabilizing device.

  The embodiment shown in FIG. 1 is a weather antenna of small size, particularly

  intended to be set up on a mobile machine.

  The weather antenna shown in Figure 1, is housed in a protection 1 of low absorption plastic She

  has two directional antennas 2, 3 of the QUAGI type.

  The antennas QUAGI 2 and 3 are correctly phased with a mechanical gain of more than 15 Dbd. Said antennas 2, 3 are activated and amplified by means of a low-noise preamplifier 4 arranged with the plastic protector 1, and this so to be able to arrange the receiver not shown on the

  Figure 1, at any distance from the weather antenna.

  The preamplifier 4 is continuously fed by a cable coaxial which connects the weather antenna to the receiver. In the embodiment shown in FIG. 2, and which is particularly intended for a mobile maritime application of the antenna, said weather antenna is provided with a three-dimensional self-stabilizing device, actuated by

three servomotors.

  Said antenna 6 is housed in a protection 7 with low absorption in the form of a small diameter ball or cylinder,

  for example 53 centimeters in diameter.

  The base of this plastic protection 7 has a trunk shape

of cone.

  Said base is attached to the superstructure of the boat and electrically connected by a cable, not shown on the

  figures, protection 7 and the electrical network.

  In this embodiment, there are four antennas 8, 9, 10 and 11 These antennas are activated in the same way by

  a preamplification device not shown in the figure.

  The antennas 8, 9, 10, 11 are provided with a three-dimensional self-stabilizing device actuated by three

servomotors 12, 13 and 14.

  All antennas are in solidarity with a first

  fork 15 supporting the four antennas 8, 9, 10 and 11.

  This first fork supports the antennas 8, 9, 10, 11 at the periphery of a disk 16 or a cross plate mounted in

  rotation on the basis of the range 15.

  This first fork 15 is rotated to rotate the disc 16 or plate cross by a servomotor or gear motor 12 which controls the rotation around the axis of

  polarization E, F of O at 360 degrees.

  Said first fork 15 is also hinged at its ends to a second fork 17 disposed in a perpendicular plane and whose rotation is actuated by the geared motor 13 controlling the elevation axis A-B of O at 90 degrees. This second fork 17 is also controlled by a

  another geared motor 14 which regulates the rotation of the azimuth axis C-

  D. This azimuth axis C-D is located at the base of the second

fork 17.

REFERENCES

  1 Mobile antenna plastic protection 2, 3 QUAGI antennas 4 Preamplifier 5 Coaxial cable 6 Maritime mobile antenna 7 Plastic protection maritime mobile antenna 8, 9, 10, 11 Antennas 12, 13, 14 Servomotors or geared motors 15 First fork 16 Disc or plate in cross 17 Second fork AB Elevation axis C- D Azimuth axis EF Polarization axis

Claims (4)

  1 Small size weather antenna characterized in that it is housed in a protection (1) of low absorption plastic, it comprises one or more antennas (2, 3) QUAGI type correctly aligned with a mechanical gain of more than 15 Dbd, said antennas (2, 3) are activated and amplified by means of a low-noise preamplifier (4) arranged at the entrance of the plastic protection (1) so as to be able to place the receiver at n any distance from the weather antenna, the preamplifier (4) is supplied with direct current by a coaxial cable (5) which connects   the weather antenna to the receiver.   Meteorological antenna of small size according to Claim 1, characterized in that, in the case of a mobile maritime application, the weather antenna is provided with a three-dimensional self-stabilizing device actuated by three servomotors (12, 13, 14), said antenna (6) is housed in a small ball-shaped or small-diameter low absorbency plastic cover (7) whose base has a truncated cone shape, said base is fixed to the superstructure of the boat and electrically connected   by a cable to the protection ball and to the electrical network.   Meteorological antenna of small size according to claim 2, characterized in that two servomotors (12, 13) regulate the antenna according to the geographical position of the boat and the third servomotor   (14) is slaved to an electronic compass.   Meteorological antenna of small size according to claim 1, characterized in that the weather antenna is housed in a protection (1) of low absorption plastic; it comprises two directional antennas (2, 3) of the QUAGI type; the QUAGI antennas (2) and (3) are correctly phased with a mechanical gain of more than 15 Dbd; said antennas (2, 3) are activated and amplified by means of a low-noise preamplifier (4) provided with the plastic protection (1) so as to be able to arrange the receiver at any distance from the weather antenna. Space weather antenna according to Claim 4, characterized in that the pre-amplification device (4) is continuously supplied with a coaxial cable (5) which connects the weather antenna to the receiver. Meteorological antenna of small size according to claim 2, characterized in that the antennas (8, 9, 10, 11) are provided with a three-dimensional self-stabilizing device actuated by three servomotors (12, 13 and 14); the set of antennas is integral with a first fork (15) supporting the four antennas (8, 9, 10 and 11); this first fork supports (the antennas 8, 9, 10, 11) at the periphery of a disk (16) or a plate cross; this first fork (15) is rotated to rotate the disk (16) or plate cross by a servomotor or gear motor (12) which controls the rotation about the polarization axis (E-F) from 0 to 360 degrees; said first fork (15) is also hinged at its ends to a second fork (17) arranged in a perpendicular plane and whose rotation is actuated by a geared motor (13) controlling the elevation axis (AB) from O to 90 degrees; this second fork (17) is also controlled by another geared motor (14) which sets the rotation of the azimuth axis (C-D) of O to 360 degrees; this axis of azimuth (C-D) is   located at the base of the second fork (17).