The invention applies to the processing of a microwave beam, corresponding to frequencies between 300 MHz and 300 GHz, length of typical waves of 1 mm to 1 m. Such frequencies are used in particular in the field:

- satellite communications from mobile platforms,

- reconfigurable data links for high-speed communications, or

- radars inexpensive to milimétriques waves.

Many applications require to be able to control the direction in which the beam is emitted and / or received. This property is called the score.

For the antenna pointing needs to be configured to emit

/ Receive a wave in a direction of the given space. For example, today in the field of telecommunications, it is increasingly required to have to redirect an antenna, following the updating of the coverage. For example, each antenna withdrawal is followed by a repositioning of neighboring antennas. Moreover, the coverage of the territory is constantly changing because it constantly seeks to improve coverage while optimizing costs thus minimizing the number of antennas. It also happens that some antennas are deleted or moved, which leads to a reorientation of neighboring antennas. It is therefore important to have intelligent, remote-controlled antennas, smart for their ability to s'

For the "tracking" or tracking, the antenna must be configured to follow a target such as a satellite.

For scanning, the beam should illuminate a defined portion of the space or scene for analysis.

In addition, increasingly seeks to steerable beam antennas, compact mass and reduced footprint, easy to use and integrate into a platform, and reduced cost.

Various known techniques enable an adjustable beam antenna, but have some drawbacks.

The Cassegrain dish is handicapped by shadowing effects due to the position of the source (more specifically by the secondary reflector) to the reflector. Also to maintain good efficiency, a large diameter ratio on wavelength is required. At low frequency, this antenna can not then be incorporated into a small volume.

In addition, conventional mechanical solutions for orienting the antenna use a gimbal mechanism in two axes. This scoring system requires significant mechanical movement since the volume occupied by the antenna varies depending on its orientation. Moreover, to avoid moving parts to active RF radiation, the transmit and receive signals must cross the microwave rotary joints that degrade performance and can be expensive and cumbersome when high power levels (several tens of Watts) are required.

To get rid of the moving parts, a known solution is to use an active antenna: profile remains flat regardless of the direction of orientation, which provides a major advantage when integration into a shroud. The orientation is controlled electrically. But this antenna has disadvantages in terms of price, power consumption (even in "off" position), complexity, heating temperature management and holding power.

A solution to realize a RF deflection system is to use two diffractive components being rotatable about a same axis, combined with a lens and an RF source. Such a system is described in the patent application WO 2014/128015. These diffractive components and the lens each have a plurality of MSs periodic wave sub-lengths microstructures formed in a dielectric material according to one of Risley scan pattern. As shown Figure 1, the component C1 diffractive structure can be manufactured on a face of the component, L the lens structure being formed on its other face. The aiming of the beam emitted by the source is provided by the independent rotations about a common axis of the double-network diffractive lens component L + C1 and C2 of the diffractive component. The advantage of such a deflection system is to be compact with a fixed power source S and guidance mechanical capabilities while ensuring a high efficiency. For example for application to 30 GHz (Ka band), using a dielectric material having a refractive index of 1 .5 (dielectric constant of 2.25), the thickness of the diffractive component is about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms. be compact with a fixed power source S and guidance mechanical capabilities while ensuring a high efficiency. For example for application to 30 GHz (Ka band), using a dielectric material having a refractive index of 1 .5 (dielectric constant of 2.25), the thickness of the diffractive component is about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms. be compact with a fixed power source S and guidance mechanical capabilities while ensuring a high efficiency. For example for application to 30 GHz (Ka band), using a dielectric material having a refractive index of 1 .5 (dielectric constant of 2.25), the thickness of the diffractive component is about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms. orientation while ensuring high efficiency. For example for application to 30 GHz (Ka band), using a dielectric material having a refractive index of 1 .5 (dielectric constant of 2.25), the thickness of the diffractive component is about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms. orientation while ensuring high efficiency. For example for application to 30 GHz (Ka band), using a dielectric material having a refractive index of 1 .5 (dielectric constant of 2.25), the thickness of the diffractive component is about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms. about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms. about 30 mm. The total thickness of the deflection system is therefore approximately 100 mm. For a source located in the object focal plane of the lens, approximately 200 mm thereof, the total thickness of the agile antenna is about 300 mm. But this thickness may still be too large for some embedded applications on mobile platforms.

In addition certain areas especially around and in the direction of the axis of rotation z of the components are difficult to point dynamically, particularly quickly. Indeed, in the same way as for the scoring systems Cardan ordered in azimuth and elevation, in this direction, the antenna pointing system has a singular area ( "keyhole" in English) which requires the use very high rotation speeds (even infinite) of the prisms to the passage of a pointed object near the axis of rotation.

Another solution based on a similar concept to that of a pair of dielectric prisms placed in front of a primary antenna, uses a phase shift area technology (or PSS acronym of the English expression "Phase Shifting Area"), described in the publication "using Rotatable phase shifting Planar Surfaces to Steer High Gain Beam" N. Gagnon and A. Petosa, 2013. the authors use a Fresnel zone plate corrected in phase by a PSS type of phase shift for generating a beam off axis, and a plate with a single linear phase progression. A phase shift surface as described in the publication of N. Gagnon and A. Petosa "Thin Transparent Microwave Quasi-Phase-Shifting Surface", 2010, is a thin self-supporting structure that introduces a phase shift in an electromagnetic wave propagating through this surface. Figures 2 is shown the configuration of a portion of PSS three metallization layers, made of conductive square elementary parts, with:

Fig 2a a sectional view (in a yz plane) showing the three conductive layers 1, 3, 5 h total thickness, separated by two dielectric layers 2, 4, permittivity ε gamma , the sides of the conductive parts for being a1 the outer layers 1 and 5 and a2 for the inner layer 3, and

Fig 2b a top view (in an xy plane) showing square cells (aside s) of the first conductive layer 1 each with a square conductive part a1 side placed on a dielectric layer 2.

The phase shift between the incident wave and the transmitted wave, and the transmission are controlled by adjusting the geometric parameters a1 and a2. This allows to obtain resonance in the structure and thus a maximum transmission for a desired phase shift. The best parameters allow to obtain phase shifts between 0 and 360 °. However, this solution has drawbacks:

a total transmission can not be obtained for all phase shifts and some configurations to achieve better than -2.2 dB (60%) of transmission. These values ​​obtained by calculation, are also optimistic because they do not consider the metal and dielectric losses.

These metallic and dielectric losses are accentuated for such an arrangement of resonant cells. To counter this effect, PCB circuits (acronym of the English expression Printed Circuit Board) low loss are required but are expensive especially with a multilayer implementation.

Furthermore, this configuration restricts the use of the concept at frequencies below about 30 GHz since metal and dielectric losses increase sharply beyond these frequencies.

Moreover, under high incidence (for angles greater scores at 30 °) the cell type can have very different transmission coefficients (phase and amplitude) for components of light polarized in the sagittal plane (s-polarization or TE) or in the perpendicular plane (p-polarized or TM) by

relative to the phase shifter surface. The result is a strong depolarization of the beam when it is pointed in the plans having no particular symmetry with the arrangement of the antenna components.

Finally, due to the configuration of resonator cells, the operating bandwidth is reduced due to operation outside the resonance due to the beam shaping which is controlled in terms of phase and not in terms of real compensation delay. A bandwidth of 7.4% (set at 1 dB maximum gain) was obtained for antennas lenses based on this concept which may be insufficient for some applications (including communications).

Accordingly, to this day remains a need for a steerable beam antenna simultaneously giving satisfaction to all of the above requirements, particularly in terms of mass and reduced footprint of use and ease of integration into a platform and reduced cost.

The approach according to the invention is based on the use of one or two dielectric components microstructures disposed in an arrangement determined by a holographic calculation.

More specifically the invention relates to a microwave antenna with steerable beam having a wavelength between 1 mm and 1 m which comprises:

a first dielectric component sub-wave length microstructures formed on a face of a dielectric substrate, a second dielectric component diffractive sub-wave length microstructures formed on a face of a dielectric substrate, configured to deflect a incident microwave beam.

It is mainly characterized in that the microstructures of the first dielectric component are located in a non-periodic arrangement to form a non-resonant holographic component dual function that is configured to collimate in the transmit mode and / or focusing in the receive mode and to deflect a beam microwave incident in that said nonresonant holographic component is associated with a first rotation mechanism about a first axis of rotation, and in that the second dielectric diffractive component is associated with a second rotation mechanism about a second rotation axis.

This antenna configuration provides a great compactness, low weight and good efficiency.

Unlike a Cassegrain dish which is penalized by shadowing effects due to the position of the source to the reflector, the antenna according to the invention operates in transmission, which allows to obtain a good efficiency and a low side lobe despite a small antenna diameter.

Furthermore, the antenna according to the invention no moving parts active RF radiation: all the electronics can be integrated closer to the source for a simpler integration, more efficient and less expensive.

As an active array antenna, the antenna profile according to the invention remains flat regardless of the direction of orientation, thus providing a decisive advantage when integration into the shroud.

Unlike the PSS antenna, the antenna according to the invention which is based on dielectric components, does not require a metal implant; it does not generate metal losses. In addition, this non-resonant configuration allows operation at wider band. For example, measured with such an antenna bandwidth (set to 1 dB of the maximum gain) as high as a 18% value, which is 240% larger than a PSS lens structure.

All these advantages lead to easier integration of a system and a platform, and this at reduced cost, particularly for small compact antennas operating on mobile platforms (truck, rail, aircraft, ...) at high frequencies between 300 MHz and 300 GHz.

According to one characteristic of the invention, the microstructures of the first and / or second component are formed on a 3D surface; when the microstructures of the second diffractive component are formed on a 3D surface, they are implemented in a non-periodic arrangement.

According to another characteristic of the invention, the microstructures of the holographic component are formed in a volume that is based on said face of the holographic component, and implanted at a non-periodic three-dimensional arrangement. Similarly to the microstructures of the second component.

The beam leaving the holographic component in transmission or in input mode of the holographic component in the receive mode, can be a plane wave with an incident angle corresponding to the orientation angle.

The first rotation mechanism is optionally associated with a first traversing mechanism of the holographic component in a plane perpendicular to the first axis of rotation.

The antenna includes means for transmitting and / or reception may be associated with a translation mechanism (designated second translation mechanism) in a plane perpendicular to the axis of rotation of the first rotation mechanism.

The microstructures of the holographic component and / or second diffractive component are advantageously implanted from a mesh bounded by iso-phase and phase gradient lines lines.

The mesh used for the holographic microstructures component may be different from the mesh used for the microstructures of the second diffractive component.

The microstructures are optionally consist of primary microstructures and coarse microstructures for performing an impedance matching layer (antireflection layer) for the weak and strong pointing angles and thus allowing not depolarize the wave passing through the component.

The steerable beam antenna preferably comprises a fairing in a microwave absorbing material, possibly with sub-wavelength microstructures, disposed within the fairing.

The invention also relates to a method for producing a steerable beam antenna as described, which comprises the following steps:

- manufacture of transmitting and / or receiving means,

- manufacturing of the holographic component and the second diffractive component in a dielectric material,

- manufacturing moving mechanisms of the holographic component and the second diffractive component,

characterized in that it comprises a step of fabricating a fairing in an absorbent material.

Other features and advantages of the invention will become apparent from reading the following detailed description, given by way of example and with reference to the accompanying drawings in which:

Figure 1 already described shows schematically in cross section an example of RF deflection system according to the prior art, based on a double component periodic microstructures with a lens on one side and a first diffraction grating on the other side, and a second periodic diffraction grating,

the already described Figures 2 show schematically cross-sectional view (Fig 2a) and top view (Fig 2b) a portion of metal plate 3 metallization layers of an example PSS type antenna,

Figures 3 show schematically sectional views of the non-periodic dielectric components of an exemplary antenna according to the invention with a single layer of microstructures (Fig 3a) and a detail of primary microstructures and microstructures second microstructures (fig 3b) ,

Figure 4 represents the phase of an exemplary diffractive lens off axis holographic according to the invention,

Figures 5a and 5b respectively represent the amplitude and phase of an output beam of an exemplary diffractive lens off axis holographic according to the invention, according to X and Y in mm, with the corresponding gain in function of the angles Θ and φ in degrees (fig 5c), and the gain pattern in the far field corresponding in function Θ (and for φ = 0 °) in degrees (fig 5d)

6a shows schematically in top view a first example of implementation of sub-wavelength microstructures constant section over the height according to a detailed Cartesian grid square to a larger scale Figure 6b, and in perspective view (Fig 6c) ,

Figure 7a shows schematically in top view a further example of implementation of sub-wavelength microstructures according to a mesh-iso-phase lines and lines to phase gradient, detailed in a larger scale in Figure 7b,

8 illustrates in perspective view an example of rotation mechanism of the second holographic component and rotation mechanism and translation of the first holographic component, with a receiver and a fixed source,

FIG 9 shows several curves of the gain pattern (in dBi) in the zOx plan based on Θ (and for φ = 0 °) in degrees, for different offsets in translation (along the x axis) of the first holographic component, with a horn stationary source,

Figures 10 illustrate the increase of the visible surface of an antenna for grazing angles of incidence between an antenna planes holographic components (surface 2D) (fig 10a) and antenna holographic components 3D surface (fig 10b) , sectional views, and exposed surfaces of curves Sa expressed in dBm 2 depending on the angle of view for different spherical surfaces of diameter D and height H and of apparent surface area of 1 m 2 at zero view angle (fig 10c )

Figure 1 1 a illustrates schematically the parasitic rays generating, Figure 1 1b shows diagrammatically in cross section an example of internal structure of the microstructures to fairing in the form of straight abutments, Figure 1 1 c another example of internal structure of fairing shaped microstructures of straight and inclined pyramids.

From one figure to another, the same elements are identified by the same references.

The antenna according to the invention comprises two dielectric components: a diffractive grating and a component dual-function lens and diffractive grating, these two dielectric components being capable of performing each rotation about an axis of rotation.

As shown in Figures 3a and 3b, the antenna comprises a single non-resonant dielectric component and on the same side thereof, the lens and the first diffraction grating and combining on the same face of the collimating lens functions and deflection of the diffraction grating (in transmission mode, and the deflection functions of the diffraction grating and the focusing lens in the receive mode). This reduces the number of components from three dielectric components (lens, the first and second diffractive grating), two dielectric components (a diffractive lens off-axis and the second diffractive grating) and thus reducing the complexity and weight of the antenna particularly in decreasing the number of rotation mechanisms associated with these components. This also reduces the overall thickness of the three components of about 33%. This results in a reduced dielectric absorption and therefore increased efficiency: 42 GHz for a material permittivity of 2.6 and a dissipation factor of 5.10"3 , improving the efficiency is 0.4 dB (10%), for example.

According to a first embodiment, this dual-function component, designated diffractive lens off-axis or first holographic component CH, comprises microstructures MS wave sub-length shown in Figure 3a, formed on one face thereof, and located in a non-periodic arrangement determined by a calculation of interference on said face, between the beam incident on this face and the desired output beam. The description is made by considering the emission mode of the antenna, the incident beam being then the beam emitted by the source; but of course the receiving mode is just as well, the output beam is then directed to the reception means. The phase of an example of first holographic component thus calculated is shown in figure 4.

It is recalled that the microstructures are characterized as subwavelength when the following condition for the cells (or meshes) which they are located, is fulfilled:

(Distance between adjacent cell centers) <λ 0 / η

with λ 0 the target wavelength selected from the wavelength range corresponding to microwaves, a wavelength typically between 1 mm and 1 m, and n the refractive index of the dielectric material wherein the microstructures are formed.

In the case where this first holographic component has a flat surface (2D space) as shown in Figures 3, 8 and 10a, it is a calculation of interference on this plane face between the incident beam emitted by the source and the output beam, in the case of a steerable beam antenna is a plane wave with an incident angle (output angle transmission mode / angle of incidence in the receive mode) corresponding to the angle beam steering. The height and size of each microstructure CH are determined experimentally or calculated so as to match the modulo 2π phase delay introduced locally by each microstructure, the conjugate of the phase hologram in the same point. It can be seen in Figures 5, an example of amplitude (Figure 5A) and phase (Fig 5b) of the output beam of a first circular holographic component 150 mm diameter operating at 42 GHz and placed at 75 mm from the source; there is obtained a deflection of 29 ° as shown in Figures 5c and 5d with the angle Θ.

The implementation of the sub-wave length microstructures on one side of the second diffractive C2 network (or second diffractive component) can also be determined by an interference computation on this side between the beam transmitted through the off-axis diffractive lens (first holographic component CH) and the desired output beam, but not necessarily. Indeed C2 microstructures may be determined as described in patent FR 3002 697. When the implementation of the microstructures is determined by the calculation of interference, this second component is designated second holographic component; this calculation is applicable to the calculation of interference applied to the first holographic component.

The sub-wavelength microstructures implementation of one and / or another dielectric component is made from a generally geometric mesh M based Cartesian, that is to say based

rectangular or square, as shown in the examples of Figures 6a, 6b and 6c. A hexagonal mesh or circular may also be considered. The meshes of the first (CH) and the second component (C2) may be the same but not necessarily. Within this network, the basis of a microstructure can of course exceed a mesh (or cell) of the mesh, but can not occupy partially. As can be seen in the example of Figure 6a, some stitches are empty, other fully occupied by the base of the microstructure and for still others, the base of the microstructure occupies only partly the corresponding mesh , determined according to the implementation. filling ratio by means the ratio between the surface of the microstructure at its base and the cell surface.

This simple implementation to realize however causes a phase error due to the resolution of the sampling and thus to a reduced efficiency of opening of the antenna. To solve this problem we choose a mesh base in a coordinate system adapted to adjust the phase at best. According to the invention achieves a geometric structure sub wavelength from a mesh M which coincides with iso-phase lines in one direction and with phase gradient lines in respective directions perpendicular to the lines iso- phases, as illustrated in FIGS 7a, 7b.

Continuing and orientation capabilities of the bundle are obtained by means of rotation of the diffractive lens out of CH and axis C2 of the diffractive component relative to another. In the case where the CH and C2 components were calculated for deflecting the beams with the same angle, a joint rotation of the two components enables azimuthal orientation while a-against rotation relative to each other allows an orientation in elevation. The zenith is then a singular point that can not be pointed that if the deflection angles of the two components are equal. In the case of an azimuth tracking, this imposes very high accelerations on the two components, which is very difficult. Stated otherwise the azimuthal tracking can not be performed that

To overcome this difficulty, the CH rotating mechanism is associated with a translation mechanism according to two axes, as shown

Figure 8. In this figure it is the rotation mechanism (indicated by a dashed circular arrow) of the first holographic component CH which is complemented by a translational mechanism 2-axis in a plane perpendicular to the first axis of rotation; the second component C2 is only equipped with a rotation mechanism (indicated by a circular arrow in solid line). This keeps fixed the receiver R and the source S of the antenna, while allowing an orientation of the beam according to two axes without additional singular point, and agility tracking near the zenith. The first and second rotational axes are no longer overlapped. CH component and the C2 component orientation mechanisms may be independent.

The source or more generally the means for transmitting and / or receiving may themselves be associated with a translation mechanism (designated second translation mechanism) in a plane perpendicular to the axis of rotation of the first rotation mechanism.

Furthermore these additional orienting capabilities can be used to generate an error signal used for controlling the tracking.

This ability to orientation has been calculated for a first circular holographic component 150 mm placed 75 mm above a 42 GHz horn source, designed to direct the beam at an angle of 28.5 °. As can be seen in Figure 9, a translation of this component between -10 and 10 mm, induces an additional deflection between -7.75 ° and + 8.5 ° with a reduction in gain of -1 dB in the worst case.

In order to improve the effectiveness of orientation for low elevation angles (high angle Θ), the microstructures of the first and / or second component may be formed on a non-planar surface that is to say on a surface 3D predetermined for each of the two components, such as a rotationally symmetric surface such as a cone, a sphere or any arbitrary 3D surface. The choice of the 3D surface is eg based on compromise performance at the zenith / grazing angles sought, or according to a desired footprint. A 3D surface makes it possible to increase the area of ​​the antenna Its apparent and therefore the gain for grazing angles of incidence as shown in Figures 10 showing

an increase in the visible surface (in dBm 2 ) Sa according to the viewing angle Θ for different 3D spherical surfaces having a diameter D and height H and of apparent surface area of 1 m 2 at zero view angle. H = 0xD configuration corresponds to a flat circular surface (10a), the surface H = 0.5xD corresponds to a hemispherical surface, and the surface H = 0.25xD (Figure 10b) to an intermediate configuration. As can be seen in the curves of Figure 10c, at 70 ° incidence, a hemispherical surface (H = 0.5 D) with respect to a flat circular surface (H = 0.0 D) changes of an apparent surface -4,7dBm of 2 to a visible surface of -1, 8dBm 2 an increase of the latter of 2.9 dB (approximately 95% increase).

In this case (= when the face of the second component is a 3D surface), the implementation of sub-wave length of the second component C2 microstructures is necessarily determined by calculation of interference indicated above; in other words the second component is necessarily a holographic component.

The microstructures are all formed in a dielectric material in a form determined a priori, is projecting in the form of pillars or recessed in the form of holes. A combination of holes and pillars is also possible. The microstructures are of any shape, preferably with axes of symmetry to make them independent of the polarization of the incident beam at normal incidence, enabling a behavior of the deflection system of the invention insensitive to polarization.

The microstructures have a square, hexagonal or circular, or a combination of different geometries, or a section according to the iso-phase lines and phase gradient lines. They may be of constant cross section over the height or variable as in the case of a pyramidal structure, conical, etc. The height of the microstructures MS is generally the same within a single component (as shown in Figure 3a), but not necessarily; it can also be identical from one component to another, but not necessarily. They can be perpendicular to the surface of the component or inclined, for example at 30 °. One can also have a variable inclination on the same component. The inclination is

determined experimentally, typically depending on the turning direction of or incidence of the beam.

According to a generalization of the previous embodiment, and always to perform the function of collimating and beam deflection, the first holographic component CH comprises overlays MS sub-wavelength microstructures layers formed in the volume of the -Cl, and implanted at a non-periodic three-dimensional arrangement determined by a calculation of interference on said volume between the beam emitted by the source incident in this volume and the desired output beam. This volume is based of course on the side of CH component on which the microstructures are formed; this volume is delimited in particular by this face. The calculation of the volume interference can be experimentally achieved by successive adjustments or by calculation, for example by transforming the volume of CH in a stack of K 2D surfaces, or 3D parallel to each other (with K a typically including integer between 2 and 100) on each of which a figure of 'interference surface is calculated. The stack of layers of microstructures is obtained for example by mapping for each calculation point of the volume, height microstructure reduced by a factor K and whose section is used to generate a local phase delay corresponding to the conjugate of the phase of the hologram in the same point of reduced a factor K. flux interference is calculated. The stack of layers of microstructures is obtained for example by mapping for each calculation point of the volume, height microstructure reduced by a factor K and whose section is used to generate a local phase delay corresponding to the conjugate of the phase of the hologram in the same point of reduced a factor K. flux interference is calculated. The stack of layers of microstructures is obtained for example by mapping for each calculation point of the volume, height microstructure reduced by a factor K and whose section is used to generate a local phase delay corresponding to the conjugate of the phase of the hologram in the same point of reduced a factor K.

Another mode to achieve the 3D microstructure distribution is based on the calculation of interference received on the side of CH component between the incident beam emitted by the source and output beam for projecting section of each of the microstructures in the volume component following the curves resulting from the intersection between the planes of isophase volume hologram and the planes containing the phase gradients. The height and the section of each microstructure CH are calculated so as to match the phase lag (modulo 2pi) introduced by each microstructure at the conjugate of the phase hologram calculated on the surface of CH.

Stated otherwise, the calculation of interference on said volume may be performed:

- discretely for different values ​​of z (dimension of the stack); it is somewhat of a reiteration for several implementation surfaces considered at different values ​​of z, the computing 2D interference previously described for a single implementation surface. The height and microstructures section is then to be fixed on each of these surfaces as indicated above, or

- continuously on z, the height and microstructures section then being determined by calculation itself.

In the case where C2 is a holographic component, this embodiment can also be applied to realize the deflecting function C2.

According to a second embodiment, the microstructures CH component and / or C2 are primary MSp microstructures and microstructures MSs side arranged in a second layer on the first layer of primary microstructures, as can be seen in Figure 3b. Their arrangement on primary microstructures and shape are determined by known means (parametric optimization algorithms) to maximize and equal transmission structure for both TE and TM polarizations and different angles of incidence of the beam, ie, is to say, to realize the impedance matching function.

Secondary microstructures are preferably pillars or holes or a combination thereof, and preferably have sections such as squares, hexagons or circles. They can also be located between the pillars of primary microstructures as shown in Figure 3b. They may be of constant or variable section over the height as in the case of a pyramidal structure, conical, etc. They can be perpendicular to the surface of the component or inclined, for example at 30 °. This addition of a layer of second microstructures (a CH and / or C2) adapts the impedance in order to obtain near transmission levels regardless of the incident polarization, and under strong under low incidence so as not not depolarize the wave incidence.

The use of secondary microstructures allows:

- to adjust more finely the desired value of the effective index so as to reduce the energy diffracted by the system in levels parasites other than the main beam, - to carry out an impedance matching layer (antireflection layer ), and

- not depolarize the wave emitted by the source, which is not the case of PSS.

Part emitted by the source and not collected ( "spillover" in English) for the CH and C2 devices may disturb the antenna radiation pattern. Indeed, the hologram component is mechanically held to the source, with a metallic or dielectric shroud. In both cases, these solutions lead to the creation of parasitic radiation or by reflection on these mechanical elements, either by transmission through the structure or 2 as shown in figure 1 1 a.

One of the obvious solutions, but suboptimal, is to coat the inside of the fairing with absorbent materials. However, given the diversity of angles of incidence to cover, control of reflections to the absorbent surface is delicate on all the surfaces to be covered.

The antenna preferably comprises a fairing in the form of microwave absorbing tube capable of maintaining the dielectric components CH and C2 in front of the horn source S, made of absorbent material to microwave (for example, organic materials loaded with absorbent materials such as metals, magnetic materials, carbon, or of weakly doped semiconductor materials) by dubbing of the structural material forming the shroud or directly. The external structure of the shroud is typically smooth while the internal structure of the tube is determined to absorb the microwave reflections that appear inside the tube when transmitting and receiving a signal. This structure can be done in two ways:

- either with the aid of a layer having microstructures wave sublongueur for the structure is locally adapted in height and thickness to present the equivalent effective index (as presented in patent FR 2,980,648), which allows to achieve an antireflection layer locally adapted to the incidence and frequency of the incident wave as shown in Figure 1 1b.

- by using a three-dimensional structure of pyramidal type for example, (see article by WH Southwell "Pyramid- array terrain-area structures Producing Antireflection index matching on optical surfaces", J. Opt Soc A., Vol 8, No.. 3, March

1991) to the interface by directing, for example, the sub-wave length microstructures according to the incidence of the beam as shown in Figure 1 1 c. This orientation is not essential, we can maintain a normal direction to the surface of the fairing. Depending on the operating wavelength of the device, the size of the microstructures is different. Achieving these structured surfaces can be made by machining, for additive manufacturing, or by chemical etching.

Manufacturing an antenna according to the invention comprises the following steps:

manufacturing means for transmitting (source) and / or reception, manufacture of the first holographic component and the second component (possibly holographic) in a dielectric substrate, optionally in a same step,

possible production of the fairing,

manufacturing moving mechanisms (rotation and eventually translation) of the first holographic component and the second component (possibly holographic),

- assembly of all these elements.

The manufacture of these components and / or the fairing to sub-wavelength microstructures can be achieved by standard molding or machining methods, using prohibitively expensive machines particularly difficult to absorb for a few

components to manufacture. As dielectric materials that can be used include: polyamide (PA), acrylonitrile butadiene styrene (ABS), polypropylene (PP), high density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyetherimide (PEI or ULTEM), polyetheretherketone (PEEK), polycarbonate (PC), cycloolefin copolymers (COC and COP), Polystyrene (PE or Rexolite), the polyphenylen sulfide (PPS and PPSF). Can also be made of ceramic materials, for example alumina (Al2O3), aluminum nitride (AlN), zirconia (ZrO2), Barium titanate (BaTiO3), titanium dioxide (ΤΊΟ2), silica, but also all composite materials to organic base and loaded with organic or inorganic dielectric material (ceramic type).

In the case where the microstructures are formed in the body of a substrate, the pillars and / or holes are formed directly in the substrate for example by the conventional manufacturing methods. But to obtain sections microstructures between 500 μηι and 2 mm with a width of the section / height of up to 20, a mold cost between 50 and 100 keuros keuros.

The dielectric components and / or the shroud are advantageously fabricated using additive manufacturing processes characterized by a high flexibility, a large-scale production and low cost manufacturing. Among these additive manufacturing processes include printing 3D modeling by depositing molten wire (or FDM acronym of the English expression Fused Deposition Modeling), stereolithography (SLA) or Selective Laser Sintering (or SLS acronym for Anglo-Saxon Selective Laser Sintering): the dielectric used are compatible with minimal absorption of the signal (estimated at -1 dB per component) and the required mechanical precision.

They can also be manufactured by a combination of these manufacturing processes.

While the invention has been described in connection with particular embodiments, it is obvious that it is not limited and it includes all the technical equivalents of the means described and their combinations if they within the scope of the invention.

CLAIMS

Microwave antenna steerable beam having a wavelength between 1 mm and 1 m, adjustable, which comprises:

a first dielectric component sub-wave length microstructures formed on a face of a dielectric substrate,

a second dielectric diffractive component (C2) to sub-wavelength microstructures formed on a face of a dielectric substrate, configured to deflect a microwave incident beam,

characterized in that the microstructures of the first dielectric component are located in a non-periodic arrangement to form a holographic component (CH) nonresonant dual function that is configured to collimate and / or focus and to deflect a microwave incident beam, in that this non-resonant holographic component is associated with a first rotation mechanism about a first axis of rotation, and in that the second dielectric diffractive component (C2) is associated with a second rotation mechanism about a second axis of rotation .

Antenna directional microwave beam according to the preceding claim, characterized in that the microstructures of the holographic component (CH) are formed on a 3D surface.

Antenna directional microwave beam according to one of the preceding claims, characterized in that the microstructures of the holographic component (CH) are formed in a volume that is based on said face of the holographic component, and implanted at a non-periodic three-dimensional arrangement.

Antenna directional microwave beam according to one of the preceding claims, characterized in that the microstructures of the second diffractive component (C2) are formed on a 3D surface, and located in a non-periodic arrangement.

Antenna directional microwave beam according to one of the preceding claims, characterized in that the microstructures of the second diffractive component (C2) are formed in a volume that is based on said face of the diffractive component, and implanted at a non-periodic three-dimensional arrangement .

directional microwave beam antenna according to one of the preceding claims, characterized in that the beam leaving the holographic component (CH) transmission or input of holographic component guide (CH) in the receive mode is a plane wave with an angle of incidence matching the angle of orientation.

7. Antenna directional microwave beam according to one of the preceding claims, characterized in that the first rotating mechanism is associated with a first traversing mechanism of the holographic component (CH) in a plane perpendicular to the first axis of rotation.

8. antenna directional microwave beam according to one of the preceding claims, characterized in that it comprises transmission means (S) and / or receiver associated with a translation mechanism in a plane perpendicular to the axis of rotation of the first rotation mechanism.

9. Antenna steerable microwave beam according to one of the preceding claims, characterized in that the microstructures of the holographic component and / or second diffractive component are implanted from a mesh (M) delimited iso phase lines and phase gradient lines.

10. Antenna steerable microwave beam according to the preceding claim, characterized in that the mesh to form the microstructures of the holographic component (CH) differs from

mesh to form the microstructures of the second diffractive component (C2).

January 1. Antenna directional microwave beam according to one of the preceding claims, characterized in that the microstructures of the holographic component and / or second diffractive component are primary microstructures (MSP) and of second microstructures (MSs).

12. Antenna steerable microwave beam according to one of the preceding claims, characterized in that it comprises a fairing in a microwave absorbing material.

13. Antenna steerable microwave beam according to the preceding claim, characterized in that the fairing includes sub-wavelength microstructures.

14. Antenna steerable microwave beam according to the preceding claim, characterized in that the shroud microstructures are within the shroud.

15. A method of manufacturing an antenna beam steerable microwave according to one of the preceding claims which comprises the steps of:

- manufacture of transmitting means (S) and / or reception,

- manufacturing of the holographic component (CH) in a dielectric substrate,

- manufacturing the second diffractive component (C2) in a dielectric substrate,

- manufacturing moving mechanisms of the holographic component and the second diffractive component,

characterized in that it comprises a step of fabricating a fairing in an absorbent material.

16. A method of making a steerable microwave beam antenna according to the preceding claim, characterized in that the holographic component (CH) and the second diffractive component (C2) are manufactured together.

17. A method of making a steerable microwave beam antenna according to one of claims 15 or 1 6, characterized in that the holographic component (CH) and the second diffractive component (C2) are produced by additive manufacturing and / or molding and / or machining and / or chemical etching and / or laser engraving.