Self-referenced radiating panel radio stimulation device

FIELD OF THE INVENTION

[001] The technical field of the invention is that of beam-forming antennas made in particular in solid state.

[002] The field of operation of the invention is that of testing and stimulating radio reception systems, in particular once installed on their carrier platform, such as, for example, radar detectors or communications interceptors.

BACKGROUND OF THE INVENTION - PRIOR ART

To stimulate a radio reception system once installed on its carrier platform without making any modification, one solution consists in resorting to a conventional generation of a radioelectric signal at a distance from said radio reception system. The distance then imposes a certain level of radiated power in the direction of said radio reception system, and solutions similar to those of operational transmitters for which said radio reception systems are made to receive the signals are naturally candidates.

For example, we fall back on radar architectures limited to transmission (reception having no interest here since only the transmitted signal is sought) and, in particular, on electronically scanned radar architectures, which present the The advantage of not requiring mechanical means to point the beam from the test antenna to the radio reception system to be tested.

[004] These architectures define generally compact devices. However, for certain applications, it is sometimes useful to be able to separate the part generating the stimulation signal with its phase law from the part which ensures its radiation, and this while retaining, as far as possible, for the latter a simple structure because , for the needs of certain applications, it can be multiplied.

[005] In this context, a technical problem consists in finding a hardware solution allowing the transport of the stimulation signal with its phase law so as to obtain the emission of the desired radio signal in the desired direction.

[006] Insofar as the existing stimulation devices are very generally compact, the state of the art does not provide a solution allowing the separation of the generation part of the stimulation signal from the radiating part.

[007] The known devices are in particular based on architectures such as those illustrated by Figures 1 and 2.

[008] FIG. 1 shows a conventional structure making it possible to generate a phase law by means of controlled phase shifters 11 connected to transmission modules 12.

[009] FIG. 2 represents a conventional structure making it possible to generate a phase law directly by means of waveform generators 21 also controlled in phase (MIMO structure for multiple inputs, multiple outputs) connected to transmission modules 12.

A solution to be able to separate the part generating the stimulation signal with its phase law, from the part which ensures the radiation consists, as illustrated in FIG. 3, in splitting the structure of the emission modules into two. which radiate the stimulation signal, at the output of the phase-shifted signals, just at the input of the power amplification stage.

This cut leads to physically group together, in a first signal generator assembly 31, the elements which produce all the phase-shifted signals which carry the phase law of the stimulation signal to be radiated, and to physically group together in a second assembly 32 , distant from the first, the elements which carry out the power amplification of the signals and their radiation. Such a solution, illustrated by FIG. 3, is, in particular, equally applicable to the structures illustrated by FIGS. 1 and 2.

However, the use of such a solution involves controlling the routing of the microwave signals produced by the first set 31, signals which can reach several tens of GHz, to the second

together 32, the two sets being able to be separated from each other by several tens of meters. This routing 33 must in fact be carried out without loss or alteration of the relative phases of the signals conveyed.

The routing of very high frequency signals from one device to another remote device by means of optical fiber links, being well known, a solution for routing the microwave signals produced by the first set 31 to the second set 32, naturally consists of the use of an offset 41 by optical fibers. Such a solution is illustrated in Figure 4.

Such a solution can be implemented according to different variants known from the state of the art. In particular, it is possible to use a number of optical fibers less than the number of signals to be routed. For this, several signals carried by laser waves of different wavelengths can be multiplexed on the same optical fiber; this wavelength multiplexing obviously involving demultiplexing on arrival.

However, the drawback of such a solution is to maintain despite everything a physical link between the two hardware units 31 and 32, which constitutes a difficulty for certain applications.

Another solution based on an optical offset between the two sets 31 and 32 consists, as illustrated in Figure 5, to route the signals produced by the set 31 through a composite laser beam each component s k , l (t) of the radiated stimulation signal being carried by a laser wave of distinct wavelength. The laser beam is directed towards a set of optoelectronic receivers arranged in a plane, a matrix of photodiodes for example, each laser wave being intended to be received by a dedicated optoelectronic receiver, connected to the emission module e i intended to radiate said component .

However, to be able to guarantee the maintenance of the desired phase law, such means must generally be accompanied by means making it possible to measure and correct the phase bias introduced by the distance and the direction of incidence (D, α , β) of the composite laser beam relative to the plane of the optoelectronic sensors, so as to transmit to each of the emission modules a signal having the required phase shift

to form the radiated signal. The addition of such means makes the implementation of such a solution more complex and reduces the advantages it provides in terms of eliminating the physical link between the assembly which generates the signals constituting the stimulation signal and the set that amplifies and radiates these signals.

PRESENTATION OF THE INVENTION

An object of the invention is to provide a solution making it possible to put into practice, in a simple manner, the principle of optical offset by a composite laser beam, of the signals making up the stimulation signals, from the sub-assembly responsible for generate these signals to the assembly responsible for amplifying and radiating these signals.

One aim of the invention consists, in particular, in the context of an optical offset solution consisting of a composite laser beam directed towards a set of optoelectronic sensors arranged in a plane, a matrix of photodiodes for example, in finding a solution making it possible to dispense with the need to set up a means for measuring and correcting the phase bias introduced, for each of the signals forming the stimulation signal, by the distance and the direction of incidence of the laser beam.

To this end, the invention relates to a device for radioelectric stimulation of an antenna comprising at least one transmission sub-assembly formed by an array of radiating elements each connected to a photoelectric receiver integrated into an array of photoelectric receivers; as well as an electrical signal generator configured to synthesize, for each radiating element, an electrical excitation signal having a determined amplitude and phase, depending on the position of the radiating element in the network, in accordance with a law of given amplitude-phase.

According to the invention, said electrical signals are transmitted to the emission sub-assembly in the form of a composite laser beam configured to illuminate the network of photoelectric receivers at a given incidence, said beam being obtained by multiplexing different modulated light waves. each by an electrical excitation signal. Eachof photoelectric receivers is configured to achieve reception of a given light wave

The array of photoelectric sensors and the array of radiating elements have substantially the same geometry with the same symmetry of distribution of the constituent elements in each array, each photoelectric receiver being connected to a radiating element occupying within its array a position identical to that that said receiver occupies within its own or a symmetrical position thereof.

According to one embodiment of the device according to the invention, the array of photodetectors and the array of radiating elements of the emission sub-assembly are carried by a same panel consisting of cells arranged in columns k and rows l, each cell comprising a photodetector and a radiating element which are substantially co-located and whose active surfaces are oriented in the same direction parallel to the axis (Oy). The signal generator sub-assembly is configured such that the emitted composite laser beam illuminates the photodetector array in a direction defined by two angles α and β in a reference frame (Οx, Οy, Οz), so that the direction according to which the radioelectric beam is radiated is determined by two defined angles α 'and β',

with a, b, c and d equal to - 1 or 1;

θ and ψ being the angles defining the deflection imposed on the radioelectric beam by the phase law generated by the signal generator subassembly.

According to a particular configuration of the device according to the invention considered in the preceding embodiment, the panel carrying the array of photodetectors and the array of radiating elements has two axes of symmetry intersecting at a center itself forming a center of symmetry . The array of photodetectors and the array of radiating elements are electrically linked by an interconnection structure connecting the output of each photodetector to the radiating element located in a

symmetrical cell of the cell in which it is located with respect to the center of symmetry or to one of the axes of symmetry.

According to a first embodiment of this configuration, the panel carrying the array of photodetectors and the array of radiating elements comprises a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel. The output of the photodetector of a cell C k, l delivers its electrical signal to the radiating element of cell C -k, -l symmetrical to cell C k, l with respect to the center of symmetry 0.

According to an alternative embodiment, the panel carrying the array of photodetectors and the array of radiating elements comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, of on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel. The output of the photodetector of a cell C k, l delivers its electrical signal to the radiating element of cell C k, -l symmetrical to cell C k, l with respect to the first axis of symmetry.

According to another alternative embodiment, the panel carrying the array of photodetectors and the array of radiating elements comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel. The output of the photodetector of a cell C k, l delivers its electrical signal to the radiating element of cell C_ k, l is symmetrical to cell C k, l with respect to the second axis of symmetry.

According to another particular configuration of the device according to the invention, the panel carrying the array of photodetectors and the array of radiating elements comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel. The output of the photodetector of a cell C k, l delivers its electrical signal to the radiating element belonging to the same cell C k, l .

According to another embodiment of the device according to the invention, the array of photodetectors and the array of radiating elements are carried by two separate panels made up of cells arranged in columns k and rows l, each cell of a first panel comprising a photodetector and each cell of a second panel comprising a radiating element. The signal generator sub-assembly is configured such that the emitted composite laser beam illuminates the array of photodetectors in a direction defined by two angles a and β in a reference frame (Ox, Oy, Oz), so that the direction according to which the radioelectric beam is radiated is determined by two angles α 'and β' defined, in a reference frame (Οx ', Oy', Oz ') homologous to the frame (Ox, Oy, Oz),

with a, b, c and d equal to - 1 or 1;

θ and ψ being the angles defining the deflection imposed on the radioelectric beam by the phase law generated by the signal generator subassembly.

According to another embodiment, the device according to the invention comprises a plurality of emission sub-assemblies and a signal generator sub-assembly, said signal generator being configured to produce a composite laser beam which can be directed onto the network. photodetectors of one or other of the emission sub-assemblies.

DESCRIPTION OF FIGURES

The characteristics and advantages of the invention will be better appreciated thanks to the following description, a description which is based on the appended figures which show:

FIGS. 1 and 2, schematic illustrations of two examples of architectures of conventional radio stimulation devices, forming part of the state of the art;

FIG. 3, a schematic illustration of the principle of physical separation of the waveform and radiation generation modules from one another;

FIG. 4, a schematic illustration of an exemplary known implementation of the principle of FIG. 3;

FIG. 5, a schematic illustration representing a stimulation device on which the principle of the invention can be applied;

FIGS. 6 and 7, diagrammatic representations of one form of implementation of the invention showing the essential characteristics of the latter;

FIG. 8, an illustration relating to a first exemplary embodiment of the embodiment of FIGS. 6 and 7;

FIGS. 9 and 10, two tables making it possible to define, for the example of implementation of FIG. 8, the angular domain of validity of the invention;

FIGS. 11 and 12, illustrations relating to a second and a third embodiment of the embodiment of FIGS. 6 and 7;

FIG. 13, an illustration relating to a fourth exemplary embodiment of the embodiment of FIGS. 6 and 7;

FIG. 14, a schematic representation of another embodiment of the invention in which the array of photodiodes and the array of radiating elements are on two independent supports;

FIG. 15, a schematic representation of another form of implementation of the invention in which the system comprises two transmission subsets.

It should be noted that, in the appended figures, the same functional or structural element preferably bears the same reference symbol.

DETAILED DESCRIPTION

[0020] FIG. 5 schematically represents the structure of a device for stimulating an antenna capable of being able to integrate the invention.

Such a device comprises, conventionally, a generator of electrical signals 51 and a transmission assembly 52 whose function is to radiate the signals produced by the generator 51 so as to form a radioelectric beam directed towards the antenna to be tested.

The transmission assembly 52 consists of N radiating elements 551 (antennas) forming a network 55, generally flat, each supplied by a power amplifier module 552.

The signal generator 51 is configured to produce N electrical signals 511 which are coherent with each other and each having, with respect to a reference signal, a phase (phase shift) determined by a phase law transmitted to the generator 51 moreover or stored in internal memory.

Each of the N signals produced is intended to supply one of the N radiating elements 551 (via its amplifier module 552). The recombination in space of the N signals 511, each radiated by an element 53, making it possible to form a beam in a given direction, a function of the phase law generated by the generator 51.

The phase of each electrical signal 511 produced by the generator 51 is determined as a function of the radiating element 551 for which it is intended and of the deflection that one wishes to impose on the beam formed with respect to a chosen reference axis , the axis perpendicular to the plane of the radiating elements for example.

The stimulation device considered here however comprises, in an original manner, the particularity of transmitting the electrical signals 511 produced by the signal generator 51 to the emission assembly 52 in the form of a composite laser beam 53 formed of N multiplexed light waves, of different wavelengths, each light wave being modulated by one of the N electrical signals produced. To do this, the signal generator 51 comprises N electro-optical modulators 512, an optical multiplexer 513 as well as an objective constituting a pointed optic 514.

The composite laser beam 53 is oriented towards the emission assembly 52 which comprises a set of N photodetectors 541. The photodetectors 541 are arranged in an arrangement forming a planar structure 54, illuminated by the laser beam 53 under an incidence given compared to the normal Oy with this structure.

Each photodetector 541 is also associated with a filter of light wavelengths 542, configured in such a way that it can only detect the light wave modulated by the electrical signal 511 which is intended for it.

According to the invention, the transmission sub-assembly 52 according to the invention has the advantageous characteristic that the arrangement of the photodetectors 541 on the network structure 54 has a geometry identical to the arrangement of the radiating elements 551 on the network structure 55. By identical geometry is meant here that the shape of the alignment of the elements on each of the structures 54 and 55 as well as the alignment pitches are identical. This identity of geometries constitutes the essential characteristic of the invention.

This structural feature is reflected in the fact that each photodetector 541 occupying a given position in the arrangement of the array 54 of the N photodetectors, corresponds to a radiating element 551 occupying an identical position in the arrangement of the array of the N elements radiating 551, these positions being for example defined by identical coordinates in the orthonormal references respectively attached to each of the arrangements.

This geometry identity has the advantageous result that the radioelectric beam formed by the arrangement of radiating elements 55 exhibits substantially, relative to the normal to the plane of the radiating elements, a deflection whose value is equal, by means of a term error, to the direction of deflection of the radioelectric beam determined by the phase law imposed by the generator 51 to which is added a direction directly linked to the direction of incidence of the composite laser beam on the arrangement 54 of photodetectors.

[0031] The direction of the radiated radioelectric beam is thus no longer referenced in absolute relative to a reference direction of the arrangement of the radiating elements, but in relative relative to the direction of incidence of the composite laser beam.

This advantageous result is more particularly obtained for

a direction of incidence of the laser beam included in a limited angular range and a direction of deflection of the radioelectric beam also included in a limited angular range, for which the error term remains acceptable for the application considered. Beyond these areas, the error term may take on a value considered as unacceptable for the application considered.

The remainder of the description presents exemplary embodiments implementing the invention in which the emission subassemblies comprise photodetectors 541 and radiating elements 551 arranged in respective arrangements having identical geometries.

Figures 6 and 7 show in schematic form a first example of a structure intended to constitute a transmission assembly 52 according to the invention. This structure is common to the various exemplary embodiments described in the remainder of the text exhibiting such a characteristic.

In this structure, the photedetectors 541, photodiodes for example, and the radiating elements 551 are arranged on a plane (xOz) 61 consisting of elementary cells 62, according to an orthogonal arrangement. Each cell 62 comprises a photodetector 541 and a radiating element 551 located in the vicinity of one another, the active zones of the two elements being oriented in the same direction. The photodetectors 541 fitted to the cells 62, photodiodes for example, are each provided with a specific optical filter 542 allowing only the wavelength λ k, l which is dedicated to it to pass.

The cells 62 are surfaces which can be rectangular, but they will be rather square in the general case. They are arranged in rows placed on either side of a first axis of symmetry, the axis (Ox), and in columns placed on either side of a second axis of symmetry, the axis (Oz ), according to a distribution having the point 0 of intersection of the two axes as the center of symmetry.

The arrangement of the antennas 551 and the photodiodes 541 at the level of the elementary cells 62 is moreover the same for each cell so that the two networks have the same geometry. They

are however slightly offset in one or the other direction of the plane (xOz).

Depending on the shape of the array of radiating elements (and consequently of the array of photodiodes), the number of cells in the rows and in the columns may be constant or vary from one column or from one row to the column or the next row.

Thus, if the two networks have a rectangular shape, the cells are, for example, arranged in 2L rows 63 on either side of a first axis of symmetry, the axis (Ox), and 2K columns 64 placed on either side of a second axis of symmetry, the axis (Oz), according to a distribution having the point O of intersection of the two axes as the center of symmetry.

In other words, the structure comprises, in this case, 4KL cells 62 arranged in K columns on either side of the axis (Ox) and in L rows on either side of the axis (Oy), of such that the
center of the cell situated in row k and column l is represented. This cell arrangement thus presents a double axial symmetry with respect to an axis Ox and an axis Oz, the point O constituting a center of symmetry.

[0039] Alternatively, if the two networks have a non-rectangular shape, a circular or elliptical shape for example, the cells 62 can also be arranged in an orthogonal arrangement. However, the number of cells 62 in a row or a column is then different depending on the position of the row or of the column with respect to the axes of symmetry, a column k or a row l comprising all the fewer cells 62 than it is further from an axis of symmetry.

In addition to electrical power supply and utility circuits, not shown in Figures 6 and 7, the transmission assembly 52 comprises a set of identical power amplifiers 552 in number identical to the number of elements radiants 551. Each power amplifier receives its input signal from a photodiode 541 of the photodiodes array 54 and delivers an amplified signal to an antenna of the radioelectric antenna array 55. The outputs of the photodiodes 541 are connected to the inputs of the amplifier modules 552 whose outputs are themselves connected to radiating sources 551.

Preferably, to minimize power losses, the power amplifiers 5524 are placed as close as possible to the radio antennas 551.

In a structure such as that illustrated in Figures 6 and 7, the elements of the arrays of radioelectric antennas (radiating elements 551) and photodetectors (photodiodes 541) belonging to the same cells 62, the radiation of the radioelectric beam and the The illumination of the array of photodiodes by the composite laser beam takes place in the same direction of space vis-à-vis the plane 61 of the arrays.

The photodiodes 541 and the antennas 551 are identified in the same way in their respective networks, by two indices k along the Ox axis and l along the Oz axis, which for reasons of symmetry each evolve positively from 1 to one. specific positive maximum value and negatively from -1 to a minimum value opposite to the specific positive maximum value.

Thus, the antenna 551 and the photodiode 541 with its filter 542 belonging to the same cell C k, l , of indices (k, l), are respectively called A k, l and P k, l .

It will be noted here that, if the networks 54 and 55 are full rectangular, the minimum and maximum values ​​are respectively -K and K in x and -L and L in z, K and L being positive integers. On the other hand, if the networks are elliptical or circular, the limits by rows or columns are expressed less simply because they depend respectively on the column or the row.

As illustrated in Figure 6, such a structure therefore receives the composite laser beam 53 transmitted by the generator 51 in a given incident direction 65 and radiates a radio beam in a given direction of emission 66.

Let α and β be the angles corresponding to the projection of the direction 65 of arrival of the laser beam 53 respectively on a plane (xOy), in which Oy represents the normal to the plane 61 passing through the center of symmetry 0 of the structure, and on the plane (xOz).

Also let α 'and β' be the angles corresponding to the projection of the direction 66 of emission of the radioelectric beam radiated by the emission sub-assembly 52, respectively in the same planes.

The values ​​of the angles α 'and β' are determined by the value of the phase law carried by the different light waves forming the composite laser beam to which are added the phase shifts affecting the waves received by the different photodiodes due to the direction incidence (α, β) of the composite laser beam 53.

In accordance with what has been said previously, because, characteristically, the networks that make up the transmission sub-assembly 52 have the same geometry, the direction 66 in which the radio beam is transmitted corresponds to the direction of deflection imposed by the phase law generated by generator 51 to which is added a direction directly linked to the direction 65 of arrival (α, β) of the laser beam.

More precisely, if the angles θ and ψ define this direction of deflection, which correspond to the projection of the direction of emission of the radioelectric beam radiated by the emission sub-assembly 52, respectively in the planes (xOy) and (xOz ), we can write :

with a, b, c and d equal to - 1 or 1.

According to the invention, the values, 1 or —1, of the coefficients a, b, c and d are determined by the interconnection links made between the photodiodes 541 and the electromagnetic antennas 551 for the application considered, each photodiode 541 being connected to a radiating element 551 by means of an amplifier element 552. In the remainder of the description, various wiring variants which can be produced within the framework of the structure of FIGS. 6 and 7 are described.

FIG. 8 illustrates a first exemplary embodiment in which a photodiode 541 P k, l belonging to a cell C k, l delivers itselectrical signal to the radiating element 551 A -k, -l belonging to the cell

C -k, -l occupying a symmetrical position in the structure of the cell C k, l

relative to the center 0.

Considering the structure illustrated by Figures 6 and 7, the formation of a radio beam in the direction (α ', β'), 67, by the network 55 of radio antennas, arranged with a pitch δ in x and in y, corresponds to the following phase law:

where respectively represent the phase shifts of

radio signals radiated by the radiating element situated in cell C -k, -l and by that situated in cell C k, l , λ being the radio wavelength in air.

The direction of arrival (α, β) of the composite laser beam 53 on the array of photodiodes 54 produced on the electrical signal carried the following phase law:

The composite laser beam 53 transmitted to the array of photodiodes 54 carries a phase law which, if it were applied directly and normally to the array 55 of radioelectric antennas would produce a radioelectric beam in the direction (θ, ψ), the angles θ and ψ being related to the previous phase law by the relations:

Furthermore, the connection of the electrical output of each photodiode P k, l to the input of amplifier 552 which delivers its power to the radio antenna A -k, -l , generates a radio beam whose direction is defined by the following phase law:

As a result, we deduce directly from what precedes the equation connecting the three directions (α ', β'), (α, β) and (θ, ψ):

The independence in k and in l leads, in view of the preceding equations, to the following solution:

Considering the preceding relations, it can be seen that if the direction given by the phase law (θ, ψ) carried by the composite laser beam is equal (θ, ψ) = (0,0) (equiphase distribution), we gets

(α ', β') = (α, β).

It is then observed that the transmission sub-assembly 52 has retrodirectivity properties similar to those of a Van Atta radiating network, known elsewhere, except that the device according to the invention is not not a fully radio-electric device but a hybrid optical-radio device.

The direction of emission 66 of the radioelectric beam is then unconditionally equal to the direction of arrival 65 of the composite laser beam 53, the directions of propagation being opposite to each other.

On the other hand, if the direction given by the phase law carried by the composite laser beam is (θ, ψ) ≠ (0,0), the relations [012] and [013] are no longer simplified as in the previous case.

However, it remains possible to express the angles α 'and β' defining the direction of the radioelectric beam formed, as follows:

Consequently, by considering the two functions ε Δβ (Ψ, B) and ε Δα (Θ, Ψ, A, B) defined by the following relations:

We can write by taking A = α, Β = β, Θ = θ and Ψ = -φ:

It is thus noted that, in the case of a phase law carried by any composite laser beam 53, corresponding to a direction (θ, ψ), the direction 66 of emission of the radioelectric beam then corresponds to the direction opposite (-θ, -ψ), carried by the direction of arrival 66 of the composite laser beam, with an error term which can be calculated from the values ​​of θ, ψ, α and β.

As a result, provided that the error terms ε Δβ (-φ, β) and

ε Δα (-θ, -ψ, α, β) can be neglected, we then have:

The interconnection structure illustrated by FIG. 8 therefore makes it possible to produce a radioelectric beam in the direction in the reference frame (O ', x', y ', z') of the

array of radiating elements merged here with the reference frame (O, x, y, z) of the array of photodiodes.

The identity of the geometry of the networks of photodiodes and radiating elements thus advantageously makes it possible to dispense with the need to calculate for each value of the phase law the correction term to be made in order to obtain a radioelectric beam on which the direction 66 does not depend. step of the direction 65 of incidence of the laser beam.

The error terms can be determined analytically from relations [016] and [017] for selected values ​​of the angles θ, ψ, α and β. It is thus possible to constitute a table giving the value of these error terms, as a function of the values ​​of the angles θ, ψ, α and β and thus to determine for a given application to determine the extents of the angular domains of the angles θ, ψ, α and β for which the error terms remain acceptable for

the application considered.

FIG. 9 shows, for the embodiment of FIG. 8, the table of values ​​of ε Δβ (—ψ, β) for ψ and β varying between + 45 ° and -45 °.

This table makes it possible to determine the angular values ​​of ψ and β defining a domain 91 in which ε Δβ (—ψ, β) remains between given limit values, between for example.

Similarly, Figure 10 shows, for the embodiment of Figure 8, the table of values ​​of ε Δα (-θ, -ψ, α, β) for a and θ varying between + 45 ° and -45 °. The table of figure 10 is given for ψ = 10 ° and β = 10 °. It makes it possible to determine the angular values ​​of a and θ defining a domain 101 in which ε Δα (-θ, -ψ, α, β) remains between given limit values, between ± 3 ° for example.

Thus, as illustrated in FIGS. 9 and 10, the angular range in which the invention more particularly shows its usefulness can be understood thanks to the two errors ε Δα and ε Δβ , previously calculated in the general two-dimensional case .

It should be noted that the error ε Δβ being only a function of two parameters, ψ and β, can be understood quite easily.

On the other hand, the error ε Δα which is a function of the four parameters θ, ψ, α and β, is less easily grasped.

However, a statistical study shows that, for example for the four parameters θ, ψ, α and β, evolving in ± 15 °, ε Δα varies between ± 5.8 ° with a standard deviation of 0.80 ° , while ε Δβ , varies between ± 1.2 ° with a standard deviation of 0.35 °. It can thus be concluded that an interval of ± 15 ° for each of the four parameters θ, ψ, α and β constitutes an angular range allowing the implementation of the invention, even with an opening of the radioelectric beam formed of approximately 6 ° in its two dimensions.

It should also be noted that the storytelling of FIG. 9 is also valid for the case of a one-dimensional system (networks consisting of photodiodes or radiating elements aligned along Ox for example). We conclude for example that, in such a case:

- for domains of a and θ, or β and ψ, of ± 25 °, ε Δα or respectively ε Δβ reaches extremes of ± 7.7 ° with a standard deviation of

1.36 °;

- for domains of a and θ, or β and ψ, of ± 20 °, ε Δα or respectively ε Δβ reaches extremes of ± 3.2 ° with a standard deviation of 0.63 °.

The detailed explanation of the principle of the invention which has been developed previously for the application example of FIG. 8, which presents a particular interconnection configuration for which the photodiode P k, l of cell C k, l delivers its electrical signal to the radio antenna A -k, -l of cell C -k, -l symmetrical to C k, l with respect to 0, can be naturally extended to other configurations of connections between the photodiodes 541 and the radiating elements 551.

In the remainder of the text, other embodiments showing other interconnection configurations are presented in a nonlimiting manner. For these other examples of implementation, one simply mentions the expression of the angles β 'and α' without repeating the details of the calculations leading to these results, calculations similar to those already developed.

FIG. 11 illustrates a second exemplary embodiment implementing the structure illustrated by FIGS. 6 and 7, in which a photodiode 541 P k, l belonging to a cell C k, l delivers its electrical signal to the element radiating 551 A_ k, l belonging to cell C_ k, l occupying in the structure a position symmetrical with cell C k, l with respect to the axis (Oz).

Calculations similar to those described above concerning the interconnection structure illustrated in FIG. 8, show that the direction of emission of the radioelectric beam is also referenced with respect to a reference direction given by the angles α and β . The direction of emission of the radioelectric beam is then defined by the angles β 'and α' corresponding to the relationships:

In other words, such an interconnection structure produces a radio beam in the direction (α ', β') “(-θ + α, ψ - β) in the reference frame (Ο ', x', y ', z ') of the array of radiating elements merged here with the reference frame (0, x, y, z) of the array of photodiodes.

We can therefore write, by introducing the terms ε Δβ and ε Δα :

the values ​​of the error terms being
calculated respectively by formulas [016] and [017], by taking A = α,

[0070] FIG. 12 illustrates a third exemplary embodiment implementing the structure illustrated by FIGS. 6 and 7, in which a

photodiode 541 P k, l belonging to a cell C k, l is connected to the radiating element 551 A k, -l belonging to the cell C k, -l occupying in the structure a position symmetrical with the cell C k, l with respect to the axis (Ox).

As for the previous example embodiment, calculations similar to those described above concerning the interconnection structure illustrated by FIG. 8, show that the direction of emission of the radioelectric beam is also referenced with respect to a direction of reference given by the angles α and β. The direction of emission of the radioelectric beam is then defined by the angles β 'and α' corresponding to the relationships:

In other words, such an interconnection structure produces a radio beam in the direction (α ', β') "(0 - α, —ψ + β) in the reference frame (Ο ', x', y ', z ') of the array of radiating elements merged here with the reference frame (0, x, y, z) of the array of photodiodes.

We can therefore write, by introducing the terms ε Δβ and ε Δα :

the values ​​of the error terms being
calculated respectively by formulas [016] and [017], by taking A = -α, B = β, Θ = θ and Ψ = -ψ.

FIG. 13 illustrates a fourth exemplary embodiment implementing the structure illustrated by FIGS. 6 and 7, in which a photodiode 541 P k, l belonging to a cell C k, l is connected to the radiating element 551 A k, l belonging to the same cell C k, l (absence of connection symmetry).

As for the previous exemplary embodiments, calculations similar to those described above concerning the interconnection structure illustrated by FIG. 8, show that the direction of emission of the radioelectric beam is also referenced with respect to

a reference direction given by the angles α and β. The direction of emission of the radioelectric beam is then defined by the angles β 'and α' corresponding to the relationships:

In other words, such an interconnection structure produces a radio beam in the direction (α ', β') "(θ - α, ψ - β) in the reference frame (Ο ', x', y ', z' ) of the array of radiating elements merged here with the reference frame (0, x, y, z) of the array of photodiodes.

We can therefore write, by introducing the terms ε Δβ and ε Δα :

the values ​​of the error terms
being calculated respectively by the formulas [016] and [017], taking A = -α, B = - β, Θ = θ and Ψ = ψ.

Figure 14 shows in schematic form a second embodiment of the transmission sub-assembly 52.

In this embodiment, the two arrays 54 (array of photodiodes 541) and 55 (array of radiating elements 551) forming the transmission sub-assembly 52 are carried by two distinct flat structures 141 and 142, oriented in the direction of one way or the other. However, they have identical geometries so that the two structures can be broken down into cells of shapes and sizes, which can be identified in an identical manner in homologous reference marks each forming a forward direction trihedron, for example. In this way, a cell C k, l of the network 54 containing a photodiode P k, l corresponds geometrically to a cell C k, l of the network 55 containing an antenna A k, l .

However, such a structure does not differ in any way, from a functional point of view, from the structure described above, except that the direction of arrival of the composite laser beam 53 on the network 54, defined by the angles α and β and the direction of emission of the radiated radioelectric beam, defined by the angles α 'and β', are referenced with respect to separate reference axes. However, insofar as the two networks have identical geometries, the angles α 'and β' always verify the relations established previously, so that the following results are retained:

with a, b, c and d equal to - 1 or 1, the values ​​of a, b, c and d being a function of the interconnection structure of the photodiodes 541 with the radiating elements 551.

The radiating panel architecture described in the preceding text thus makes it possible to design and produce radioelectric antenna test systems made up of two physically separate entities: a sub-assembly 51 generating a given phase law and an emission sub-assembly 52 radiating this phase law, the phase law being transmitted from the first to the second sub-assembly, without material support, via a composite laser beam.

The architecture according to the invention thus advantageously makes it possible to overcome the mutual orientation of the two sub-assemblies 51 and 52 and, in particular, the bias on the phase law caused by the direction of arrival of the composite laser beam, said bias being reflected in the direction of the radiated electromagnetic signal by an angular shift of constant value equal to the angular difference between the direction of arrival of the laser beam and the reference axis of the array of photodiodes 54 receiving this latest. A system for correcting, on generation, the phase law transmitted to the emission sub-assembly 52, to take into account the angle of incidence of the laser beam, is therefore advantageously not necessary.

FIG. 15 illustrates a variant of the structure of the test system according to the invention. In this variant, the system comprises a waveform generation sub-assembly 51 and several radiating sub-assemblies 52 placed at distinct locations, the waveform generation system 51 then comprising a pointed optic capable of directing the light. composite laser beam 53 in different directions, each under

emission assembly 52 being illuminated by laser beam 53 sequentially.

CLAIMS

1. Device for radioelectric stimulation of an antenna comprising at least one transmission sub-assembly (52) formed by an array (55) of radiating elements (551) each supplied by a signal from a photoelectric receiver (541) integrated with an array of photoelectric receivers (54); as well as a generator (51) of electrical signals (511) configured to synthesize, for each radiating element (551), an electrical excitation signal (511) having a determined amplitude and phase, depending on the position of the radiating element in the network (55), in accordance with a given amplitude-phase law, said electrical signals (511) being transmitted to the transmitting sub-assembly (52) in the form of a composite laser beam (53) configured to illuminate the array (54) of photoelectric receivers (541) at a given incidence, said beam being obtained by multiplexing different light waves (513) each modulated by an electrical excitation signal (511) ); the device being characterized in that each of the photoelectric receivers (541) is configured to perform reception of a given light wave (513) and in that the array (54) of photoelectric sensors (541) and the array of elements radiating elements (551) have substantially the same geometry with the same distribution symmetry of the constituent elements (541, 551) in each network,

2. Radio stimulation device according to claim 1, characterized in that the array (54) of photodetectors (541) and the array (55) of radiating elements (551) of the transmission sub-assembly (52) are carried by a single panel (61) consisting of cells (62) arranged in columns k and rows l, each cell (62) comprising a photodetector (541) and a

radiating element (551) substantially co-located and whose active surfaces are oriented in the same direction parallel to the axis (Oy); the signal generator sub-assembly (51) being configured such that the emitted composite laser beam (53) illuminates the photodetector array in a direction defined by two angles a and β in a reference frame (Ox, Oy, Oz) , so that the direction in which the radioelectric beam is radiated is determined by two angles α 'and β' defined, in the reference frame (Ox, Oy, Oz), by the relations:

with a, b, c and d equal to - 1 or 1;

θ and ψ being the angles defining the deflection imposed on the radioelectric beam by the phase law generated by the signal generating sub-assembly (51).

3. Radio stimulation device according to claim 2, characterized in that the panel (61) carrying the array of photodetectors (54) and the array (55) of radiating elements having two axes of symmetry intersecting at a center forming it - even a center of symmetry, the array of photodetectors (54) and the array of radiating elements (55) are electrically linked by an interconnection structure making it possible to orient the electrical output signal of each photodetector (541) towards a radiating element (551) located in a cell (62) symmetrical to the cell in which it is located with respect to the center of symmetry or to one of the axes of symmetry.

4. Radio stimulation device according to claim 3, characterized in that the panel (61) carrying the array of photodetectors (54) and the array of radiating elements (55) comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel (61), the output of the photodetector (541) of a cell C k, l delivers its electrical signal to the radiating element (551) of cell C -k, -l symmetrical to cell C k, l with respect to the center of symmetry 0.

5. Radio stimulation device according to claim 3, characterized in that the panel (61) carrying the array of photodetectors (54) and the array of radiating elements (55) comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel (61), the output of the photodetector (541) of a cell C k, l delivers its electrical signal to the radiating element (551) of the cell C k, -l symmetrical to the cell C k, l with respect to the first axis of symmetry.

6. Radio stimulation device according to claim 3, characterized in that the panel (61) carrying the array of photodetectors (54) and the array of radiating elements (55) comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 2L rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel (61), the output of the photodetector (541) of a cell C k, l delivers its electrical signal to the radiating element (551) of cell C -k, l symmetrical to cell C k, l with respect to the second axis of symmetry.

7. Radio stimulation device according to claim 3, characterized in that the panel (61) carrying the array of photodetectors (54) and the array of radiating elements (55) comprising a plurality of cells, arranged in 2K columns placed on either side of a first axis of symmetry and 21 rows, on either side of a second axis of symmetry perpendicular to the first axis of symmetry and intersecting the latter at a point 0 of the panel (61), the output of the photodetector (541) of a cell C k, l delivers its electrical signal to the radiating element (551) belonging to the same cell C k, l .

8. A radioelectric stimulation device according to claim 1, characterized in that the network (54) of photodetectors (541) and the network (55) of radiating elements (551) are carried by two separate panels (141, 142) formed of cells (143, 144) arranged in k columns and I rows, each cell (143) of a first panel (141) including a photodetector (541) and each cell (144) of a second panel (142) comprising a radiating element (551); the signal generator sub-assembly (51) being configured such that the emitted composite laser beam (56) illuminates the photodetector array (54) in a direction defined by two angles α and β in a reference frame (Ox, Oy , Oz),

with a, b, c and d equal to - 1 or 1;

θ and ψ being the angles defining the deflection imposed on the radioelectric beam by the phase law generated by the signal generating sub-assembly (51).

9. Device for radioelectric stimulation of an antenna according to claim 1, characterized in that it comprises a plurality of transmission sub-assemblies (52) and a signal generator sub-assembly (51), said signal generator. being configured to produce a composite laser beam capable of being directed onto the photodetector array (551) of either of the emission subassemblies.