JPH03110905A - Multiple beam antenna through which direction is convertible by low level switch - Google Patents

Abstract

PURPOSE: To markedly enhance overall efficiency of a sub-system, consisting of antenna and amplifiers by forming a coverage with (m) spot beams and making each spot beam correspond to a prescribed number of active element sources and providing an electronic circuit with at least one low level switch which connects the input to one of the outputs. CONSTITUTION: The electronic circuit for the antenna consists of a low level switch C1, which connects an input E1 to one of radiator assemblies corresponding to spot beams Spi, and an amplifying stage 16 which has (m) inputs and (m) outputs and includes first and second general couplers 17 and 18, arranged on both sides of (m) parallel amplifiers 19 and has (m) filter 20 connected to outputs of amplifiers 19. If the amplifying stage has 16 inputs and 16 outputs (m=16), the first and second general couplers 17 and 18 included in the amplification stage 16 consist of assemblies of hybride couplers 21, arranged on both sides of plural amplifiers 19 corresponding to filters 20 respectively. Thus respective inputs of the first general coupler 17 are distributed among a plurality of amplifiers 19 and is consequently distributed among all the outputs of hybrid couplers of the first general coupler 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-beam antenna that can change direction by low-level switching.

First j1 branch! I-Spontomo - M in 1982 as part of the Telecommunications Science and Technology Series.
“TI! lecommuni” published by asson
cationsSpaLiales (Space Communications)'', more specifically Volume 1 thereof, pages 92-94 and 259.
Pages 1 to 261 describe a method of combining multiple antennas that simultaneously receive from the same transmitter into one aggregate via a power divider and a phase shifter. The radiation characteristics of this assembly depend on the diagram of each antenna and the power distribution in terms of amplitude and phase. This property can be exploited to obtain diagrams that cannot be obtained with a single source. By changing the characteristics of the power divider and phase shifter by electronic means, the diagram can be changed almost instantaneously. The simplest source collection is an array in which all the sources are of the same type and differ from each other only in position (translational displacement). In this case, linear or planar arrays can be formed.

The document also describes the use of reflector antennas to generate multiple moving beams.

This antenna uses an optimized amplification stage and has the advantage of low mass. The reflector illumination system is usually eccentric with respect to the reflector to avoid blocking the emission aperture and to facilitate placement on the platform when used on a satellite. The main reflecting mirror has, for example, a paraboloid. The moving beam consists of a combination of elementary beams obtained by placing a set of illumination sources close to the focal point. Each radiation source corresponds to one fundamental beam.

The illumination source cannot be placed exactly at the focal point, so the illumination is geometrically imperfect and thus phase aberrations occur. This phase aberration degrades the radiation performance somewhat, so the gain is less than what would be obtained when the source was in focus. These reductions increase as the defocus and mirror curvature increase. Therefore, the reflecting mirror must be made as "flat" as possible.

In other words, the ratio of focal length to aperture must be increased.
However, in that case, the size of the structure increases;
Mechanical strength and precision problems arise.

When used in satellite communications, which require electronic deflection of external waves over a wide field of view, some angular deviations of the beamwidth occur.

Therefore, it is essential to be able to accurately control the shape of the antenna diagram.

The placement of these large antennas must also consider various system factors, such as:

Satellite size limitations in view of the need for simultaneous transmitting and receiving antennas; compatibility with simple mechanical layouts on the platform and on the launch vehicle before and during operations; adequate temperature control; , multifunctional possibilities according to different users.

It is an object of the present invention to solve the aforementioned problems and to enable the antenna+amplifier subsystem to operate with extremely high overall efficiency regardless of the number of users (which can be as small as, for example, 5 or less). Another object of the present invention is to provide an antenna that can change direction with low-level switching.

1. Field of the Invention The present invention relates to a multi-beam antenna that can change direction by low-level switching. The antenna includes an energy-focusing reflective input and an electronic circuit having an amplification stage with m outputs, the coverage being formed by r spot beams, each spot beam having a predetermined number of active element sources. , characterized in that said electronic circuit has at least one low-level switch for connecting an input to one of the outputs.

Compared to mechanical approaches, the invention has the advantage that there is no need to move the radiation source or reflector. With the present invention, short focal lengths (small antennas) can be used and multiple links can be obtained simultaneously.

The present invention has the following advantages over methods using direct emitting arrays.

Antenna performance is not directly related to the overall size of the array.

It does not necessarily have to be installed on the side of the satellite facing the earth.

The antenna of the present invention has the following advantages over using a single reflector image array.

The overall size of the array is small.

High antenna efficiency.

Also, the compactness of the antenna of the present invention is evident when compared to the use of a double reflector image array.

The features and advantages of the invention will become clearer from the following description of non-limiting examples based on the accompanying drawings.

■My friend! The antenna of the present invention shown in FIG.
0, this reflector receives a beam from a planar array 11 of radiation sources placed in the vicinity of its focal point F. Array 12 is a virtual source array corresponding to array 11.

FIG. 2 shows two directions Ox at the level of the radiation source array 11.
and various amplitude distributions when moved according to OY.

The diameters of the circles shown in FIG. 2 represent the amplitudes of the signals received by the various sources of the array.

If the sensor has a fixed distribution law, the efficiency of capturing these various energy distributions cannot be optimal, and the same is true for the phase distribution.

Virtually displacing the radiation source with respect to the focal point of the reflector therefore reduces the efficiency of the antenna.

When a specific coverage is formed by multiple spot beams, the directivity performance of the antenna is determined by the degree of overlap of these spot beams.

The antenna of the invention is designed to use m spot beams, each spot beam being associated with a predetermined number of radiators or sources. All radiators corresponding to a given spot beam do not move at the same time.The electronic circuit for this type of antenna of the invention, in the embodiment shown in FIG. 3, includes the following components:

A low level switch CI connecting the input E1 to one of the radiator assemblies corresponding to the spot beam SPi.

m parallel amplifiers 1 with m inputs and m outputs
first and second general-purpose couplers 1 arranged on both sides of 9, respectively;
The output of the 16° amplifier 19 includes m
filters 20 are connected.

As shown in FIG. 4, in an embodiment having 16 inputs and 16 outputs (m = 16), the first general-purpose coupler 1
A first universal coupler 17 included in the amplification stage 16 such that each input of the first universal coupler 17 is distributed between all amplifiers 19 and thus between all outputs of the hybrid coupler of the first universal coupler 17. and the second general-purpose coupler 18, respectively,
It is composed of a hybrid coupler 21 assembly arranged with a plurality of amplifiers 19, one each corresponding to a filter 20, sandwiched therebetween. In this way, the amplifier 19 has a constant input power and can therefore operate at its nominal capacity.

In this amplification stage 16, for example, a signal applied to the first input is amplified and sent out from the first output.For example, when a signal is applied to the input of rank i, this signal is amplified by all the amplifiers. is sent to the corresponding output (rank i), and no signal is given to the other outputs. A signal applied to one of the input ports of a general-purpose coupler has n outputs of equal amplitude if and only if no signal coherent with respect to this signal is applied to any other input. divided into components.

Addressing a source or a set of sources corresponding to a spot beam from input E creates an energy route between them. A correspondence occurs between the spot beam and the input E at a predetermined time, and in this way various spot beams SPI to Sl'n are designated in sequence.

If there are multiple users, at least one second switch C1 may be used to duplicate the inputs, as in the example shown in FIG. In that case, the combination of the signals is effected via couplers (not shown) well known to those skilled in the art.
It will be carried out in

In the antenna of the present invention, the coverage to be formed is divided into m regions. For each of these m regions, a set of radiation sources in the primary array of antennas radiates a beam SPi.

In principle, each radiation source is used for the radiation of a single beam SPi. The degree of overlap between the beams, determined at the boundaries of the regions, is relevant to the optimization of the excitation coefficient of the radiation source.

In practical operation, the coefficients are determined in amplitude and phase by a fixed distribution device Ri.

This antenna establishes a correspondence between a given coverage arrangement and m independent bauds. Therefore,
An amplification stage containing a general-purpose coupler with m inputs/outputs allows an optimal tuning (constant input load) of m amplifiers 19, independent of the Subop I-beam SPi in question.

To send a signal in any direction of coverage, one need only address the input signal of the amplifier stage 16 that corresponds to the area containing that direction.

The ratings of the m amplifiers 19 are determined so that the required radiant energy can be obtained. Expansion to multi-user operation (number of users = p>) is achieved by connecting one connection circuit Ci.

This connection is made using low-level techniques, in which case the amplifier is rated according to the sum of energy to be radiated.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited thereto, and various modifications can be made, for example, by replacing the constituent members with other equivalent members.

[Brief explanation of drawings]

FIG. 1 is a simplified explanatory diagram of the scanning antenna of the present invention, FIG. 2 is an explanatory diagram of the operation of the antenna of the present invention, and FIG. 3 is an explanatory diagram showing a first embodiment of the electronic circuit of the antenna of the present invention. FIG. 4 is an explanatory diagram showing one of the stages of the electronic circuit of FIG. 3, and FIG. 5 is an explanatory diagram showing a second embodiment of the electronic circuit of the antenna of the present invention. C1...Low level switch, 17.18...
...General purpose coupler, 19...Amplifier, 20.
·····filter. FIG.1

Claims (3)

[Claims] (1) A multi-beam antenna whose direction can be changed by a low-level switch, including a reflector that focuses energy and an element source that is placed in the focal region of the reflector and combines electromagnetic fields within the focal region. and an electronic circuit having an amplification stage with m inputs and m outputs, the coverage being formed by m spot beams, each spot beam corresponding to a predetermined number of active element sources. , a multi-beam antenna capable of changing direction by means of a low-level switch, characterized in that said electronic circuit has at least one low-level switch for connecting an input to one of the outputs. (2) Claim 1 characterized in that the amplification stage includes first and second general-purpose couplers respectively placed on both sides of m parallel amplifiers, and a filter is connected in series to each of the amplifiers.
Antenna described in. (3) the first and second general purpose couplers are arranged such that each input of the first coupler is distributed between all the amplifiers and thus between all the outputs of the hybrid couplers of the first general coupler; , each consisting of one hybrid coupler assembly, the second universal coupler having an opposite structure to the first universal coupler.