ES2784328T3 - Manufacturing process of a dielectric piece with meshes that form a solid three-dimensional network and a dielectric piece thus manufactured - Google Patents

Abstract

Manufacturing process of a dielectric part in which several dielectric materials are embedded, of which at least one is in a solid state, said dielectric materials having at least one relative electromagnetic constant εr, μr of different values, characterized by that: - said imbrication is carried out by selecting: - (15) an imbrication structure of said dielectric materials formed by a three-dimensional solid network constituted by a repetition in all directions of the mesh space (20, 30, 40, 50, 60, 70, 80, 90, 100) of at least one, in solid state, of said dielectric materials, and in which each homogeneous zone of one of said dielectric materials has in any direction of space a maximum dimension less than an amax value = α. λ0, in which α is a real number less than 10, and λ0 is a wavelength of electromagnetic radiation for which the dielectric part must be adapted, - and (12) dielectric materials adapted to allow a manufacture of the solid three-dimensional network by three-dimensional printing of each solid dielectric material, - the dielectric part is manufactured by three-dimensional printing of the solid three-dimensional network, so that the dielectric part has at least one tensor [εr], [μr] determined of at least one relative electromagnetic constant εr, μr.

Description

DESCRIPTION

Manufacturing process of a dielectric part with meshes that form a solid three-dimensional network and dielectric part thus manufactured

The invention relates to a method of manufacturing a solid dielectric part that has at least one tensor [er], [| Jr] determined from at least one relative electromagnetic constant er, jr, by imbrication of various dielectric materials of the which at least one is in a solid state. It extends to a solid dielectric part thus manufactured.

In some applications such as miniaturized antennas formed by metamaterials for transmissions in the field of hyperfrequencies (frequencies greater than 100 MHz), it is sought to use dielectric substrates that present certain electromagnetic characteristics so that the dielectric substrate present in turn a certain electrical and / or magnetic response to an electric and / or magnetic field.

It is known that it is possible to control the effective value of at least one relative electromagnetic constant (relative dielectric permissiveness and / or relative magnetic permeability) of a dielectric part by embedding of several dielectric materials that have different values for this relative electromagnetic constant. This type of nesting can be carried out according to different known procedures, in particular by chemical means; via sol gel; by engraving, drilling (micro machining); or by molding (for example see US 2014/0057072), etc.

Chemical or sol gel processes do not allow precise control of the interlocking structure of the materials, and therefore the effective value of an electromagnetic constant and its gradient and / or its anisotropy within the dielectric part. In particular, they do not allow obtaining values of an electromagnetic constant distributed according to a given tensor. Furthermore, the results obtained most frequently show a large dispersion, the accuracy of the effective value of the electromagnetic constant being able to be guaranteed only with an accuracy that is at most of the order of 10%. This low reliability prevents its use in the fields in which the manufacturing procedures and / or the dielectric parts must be able to be certified, for example in the space or aeronautical industry.

Some mechanical procedures (engraving, drilling, molding, etc.) make it possible to control the nesting structure. However, this control is not very precise, and requires long, complex and expensive steps, particularly when it is desired to obtain a significant gradient and / or a strong anisotropy within the part.

Furthermore, the inventor has determined that it could be advantageous, at least in certain applications, to incorporate and / or circulate at least one dielectric material in a fluid state (ie liquid and / or gaseous) in said dielectric part. For example, in space applications, when one of the dielectric materials is atmospheric air incorporated in cells of a solid dielectric material in the ground manufacture of the dielectric part, it is convenient to ensure either a total absence of degassing, or a degassing perfect of the whole of the dielectric piece, included in its nucleus, when the latter is placed in the space vacuum. Furthermore, the incorporation and / or circulation of a heat transfer fluid within the part can allow efficient and precise thermal control. However, such an incorporation needs to be able to simultaneously have great freedom in the geometry and dimensions of the nesting structure, and a very great precision in its practical implementation.

The publication "3D printing of anisotropic metamaterials" CR Garcia et al., Progress in electromagnetics research letters EMW Publishing, USA, vol. 34, 2012, pages 75-82, describes a method of manufacturing a dielectric part according to a uniaxial network in three dimensions exhibiting an effective dielectric permissiveness anisotropy by three-dimensional printing of polycarbonate. Such a uniaxial network offers only limited possibilities for variations in the dielectric permissiveness of the part. In particular, said uniaxial network does not produce a dielectric permittivity gradient simultaneously with an anisotropy, and does not allow the incorporation and / or circulation of a fluid within said dielectric piece to be controlled. Furthermore, it does not allow the other characteristics of the dielectric part to be optimized in good conditions, in particular the mechanical and / or thermal and / or optical characteristics.

The invention therefore aims to alleviate these drawbacks.

In particular, it envisages proposing a method of manufacturing a dielectric part that allows precise control of the value of at least one relative electromagnetic constant at any point on the dielectric part, and in particular with gradients and / or anisotropies of this value, that is, a tensor distribution of values of this electromagnetic constant in the volume of the dielectric part.

It thus envisages proposing a method of manufacturing a dielectric part that has at least one tensor [er], [Jr] determined from at least one relative electromagnetic constant er, jr (that is, it has a effective relative dielectric permittivity tensor [er], and / or an effective relative magnetic permeability tensor [ ^{| J} r]) whose values can be precisely determined. In this regard, it provides in particular to allow a certification of the manufacturing process and / or of the characteristics of the dielectric part compatible with the regulatory requirements, in particular in the fields of the space or aeronautical industry.

More particularly, it envisages proposing a method for manufacturing a dielectric part intended to be used in the field of hyperfrequencies, that is to say for frequencies above 100 MHz, and / or for wavelengths between 3 mm and 3 m.

It also envisages proposing a process for the manufacture of a dielectric part that allows to obtain an incorporation -in particular a uniform incorporation- and / or a circulation in said part of at least one dielectric material in a fluid state that can be selected from among numerous liquid compositions and / or soft drinks (including space vacuum).

It also envisages proposing a manufacturing process of this type that also allows other characteristics of the dielectric part to be controlled, in particular characteristics selected from the group of mechanical characteristics, thermal characteristics, optical characteristics, and the fluidic characteristics (incorporation and / or circulation of at least one fluid within the part).

Throughout the text, the following terminology is adopted:

- electromagnetic constant: dielectric permissiveness or magnetic permeability,

- fluid: liquid and / or gas (including space vacuum),

- mesh: any polyhedral geometric motif (that is, it has flat faces or of which at least a part of the faces may be warped) and / or polygonal (that is, it has sides or edges that are straight segments and which at least part of the sides or edges may be curved) of a finished part of a solid network,

- elementary mesh: any mesh that allows the generation of at least one area of a solid network by homothetic translation with a ratio equal to or not 1,

- peripheral meshes: meshes located on the periphery of a dielectric part,

- non-peripheral meshes: meshes other than peripheral meshes,

- curved polyhedral mesh: mesh that has the shape of a curved polyhedron, that is, it has at least one warped face and / or at least one curved edge,

- solid wall of a three-dimensional solid network: any solid portion of the network; It can be either a solid or open face, or a more or less thick edge.

The invention therefore relates to a method of manufacturing a dielectric part in which an imbrication of several dielectric materials is carried out, of which at least one is in a solid state, said dielectric materials having at least one relative electromagnetic constant er, jr of different values, characterized in that:

- this nesting is carried out by selecting:

◦ an interlocking structure of said dielectric materials formed by a three-dimensional solid network made up of a repetition in all directions of space -particularly in three orthogonal directions of space- of meshes of at least one, in solid state, of said materials dielectrics,

◦ and dielectric materials adapted to allow manufacturing of the three-dimensional solid network by three-dimensional printing of each solid dielectric material, in which each homogeneous zone of one of said dielectric materials has, in any direction of space, a maximum dimension less than one amax value = a. Ao, in which a is a real number less than 10 -in particular less than 1, in particular less than 0.1-, and Ao is a wavelength of an electromagnetic radiation for which the dielectric part must be adapted,

- the dielectric part is manufactured by three-dimensional printing of the three-dimensional solid network,

such that the dielectric part has at least one tensioner [er], [jr] determined from at least one relative electromagnetic constant er, jr.

The invention also extends to a dielectric part obtained by a process according to the invention. A dielectric part according to the invention is intended to be used in radiation of wavelength Ao.

The invention therefore relates to a dielectric part that comprises an imbrication of several dielectric materials of which at least one is in the solid state, and which has at least one relative electromagnetic constant er, jr of different values,

characterized in that said imbrication is carried out according to an imbrication structure of said dielectric materials formed by a solid three-dimensional network:

- consisting of a repetition in all directions of space - in particular in three orthogonal directions of space - of meshes of at least one, in solid state, of said dielectric materials,

- in which each homogeneous zone of one of said dielectric materials has, in any direction of space, a maximum dimension less than a value amax = a. Ao, in which a is a real number less than 10 -in particular less than 1, in particular less than 0.1-, and Ao is a wavelength of an electromagnetic radiation for which the dielectric part must be adapted,

- printed by three-dimensional printing, such that it has at least one tensor [Er], [jr] determined from at least one relative electromagnetic constant er, j r.

Thus, in a method and a piece according to the invention, the nesting structure is a solid three-dimensional mesh interlocked, that is, a three-dimensional paving of the space by said meshes and presents, like a solid crystalline network, in any direction of space, that is, in each of the three orthogonal x, y, z directions of any fixed orthogonal reference point with respect to said piece, a repetition of several adjacent meshes. In other words, in any direction of space, the part according to the invention has a number of adjacent meshes greater than 1.

The result of this is that it is possible to obtain a dielectric part that has at least one tensor [er], [jr] determined from at least one relative electromagnetic constant er, jr whose value at any point in the part, particularly in any mesh of the three-dimensional lattice, it can be precisely selected and controlled, including exhibiting at least one gradient and / or one anisotropy. Furthermore, it turns out that it is possible to confer on this dielectric part other characteristics, in particular characteristics selected from the group of mechanical characteristics, thermal characteristics, optical characteristics, and fluidic characteristics (incorporation and / or circulation of at least one fluid inside the part). The inventor has in effect determined that with said solid three-dimensional network, there are numerous different nesting structures that all have the same electromagnetic properties, that is to say at least the same [er], [jr] tensor, even some [er] tensors of identical dielectric permissiveness and [jr] of magnetic permeability, and that it is possible to select and size an nesting structure as a function of said other desired characteristics for the part according to the invention.

In particular, advantageously, a method according to the invention has the following successive steps: - a step in which at least one tensor [er], [jr] is selected from at least one relative electromagnetic constant er, jr,

- a stage in which at least one dielectric material in solid state and at least one dielectric material in fluid state are selected constituting the dielectric part to be manufactured, each dielectric having a known value e „, jri of at least a relative electromagnetic constant, the known values ^e „, jri being different for the different dielectric materials and selected so that each value of each tensor [Er], [jr] can be obtained from said at least one relative electromagnetic constant Er, jr by imbrication of the different dielectric materials,

- a stage in which said amax value is selected, and at least one three-dimensional solid network that presents proportions of the different dielectric materials that make up the dielectric part adapted to provide each value of each tensor [Er], [jr] of said at least one relative electromagnetic constant Er, jr,

- a stage in which other characteristics of the dielectric part are selected -in particular characteristics selected from the group of mechanical characteristics, thermal characteristics, optical characteristics and fluidic characteristics (incorporation and / or circulation of at least one fluid inside the part) -,

- a stage in which the geometry and topology of said three-dimensional solid network is selected that allows to obtain said other characteristics.

The dielectric part is then manufactured by three-dimensional printing of this three-dimensional solid network. A fluid can then be incorporated into said three-dimensional solid network.

On the other hand, advantageously and according to the invention, at least one of the dielectric materials is selected in a fluid state. The solid three-dimensional network incorporates each dielectric material in a fluid state in its meshes. The solid three-dimensional network and dielectric materials are selected to allow the incorporation of each fluid dielectric material into the meshes of the solid three-dimensional network. This incorporation can be carried out when three-dimensional printing takes place and / or in a later incorporation stage.

Advantageously and according to the invention, at least one of the dielectric materials is selected in a fluid state, and a three-dimensional solid network that has at least one mesh open in at least two different directions forming a non-zero angle different from 180 °. In this way, a non-linear circuit of fluid (s) can be created within the dielectric part. It has been found that the fact of providing openings in the meshes of a three-dimensional solid network according to at least two different non-collinear directions in space makes it possible to organize a flow of fluid within at least a part of this three-dimensional solid network. Said circulation makes it possible to incorporate one or more fluids within at least a part of the three-dimensional solid network, in a uniform manner, for the manufacture of the dielectric piece. It also makes it possible to provide a flow of fluid (s) through and / or within at least a part of the three-dimensional solid network when the part is used. It can be for example (non-limiting list) heat transfer fluids, conductive liquids, electrolytes, liquid crystals, ionized gases (plasmas), etc. It should be noted that the invention also makes it possible in particular to vary the properties of at least said fluid, and therefore of the dielectric part, over time.

In some embodiments, advantageously and according to the invention, at least one of the dielectric materials is selected in a fluid state, and a three-dimensional solid network of which all non-peripheral meshes are open in at least two different directions of space forming between them a non-zero angle different from 180 °.

In other embodiments, advantageously and according to the invention, only a part of the non-peripheral meshes of said three-dimensional solid network is open in at least two different non-collinear directions of space (forming a non-zero angle different from 180 ° ). Thus, for example, it is possible to define at least one internal circuit, looped or not, for circulating fluid in one piece according to the invention. An open face is polygonal in the sense defined above.

In some embodiments, advantageously and according to the invention, a solid three-dimensional network is selected from which all non-peripheral meshes have the same geometric pattern, even are identical (same geometric pattern and same dimensions), which corresponds to an elementary mesh of the three-dimensional solid network. This elementary mesh is in turn three-dimensional, that is, it is repeated by homothetic translation with a relation equal to or not 1 in each of the three dimensions of space, that is, in any direction of space, therefore in each of the three directions of any fixed orthogonal reference point with respect to the part. The solid three-dimensional network (and the piece according to the invention) therefore results from a three-dimensional paving of the space from an elementary mesh, which is therefore selected from the group of elementary meshes suitable to generate a three-dimensional paving of the space. space.

In other embodiments, advantageously and according to the invention, the non-peripheral meshes of said solid three-dimensional network are not all identical, or not all have the same geometric pattern. For example, the network can be formed by a plurality of juxtaposed sub-networks each formed by non-peripheral meshes of the same geometric pattern.

In some embodiments, advantageously and according to the invention, a solid three-dimensional network is selected from the group formed of networks that have meshes that have solid walls arranged included in faces of straight polyhedral meshes and networks that have walls solid elements arranged included in curved polyhedral mesh faces.

In particular, in some embodiments, advantageously and according to the invention, said solid three-dimensional network is selected from the group formed by the networks of regular hexahedral -in particular parallelepiped, in particular cubic- with open faces, by the networks of Hexahedral meshes -particularly parallelepipedic, in particular cubic- regular that have some closed faces, by hexahedral meshes -in particular parallelepipedic, in particular cubic- irregular with open faces, by hexahedron meshes -in particular parallelepipedic, in particular cubic-irregular that have some closed faces, by the networks of regular tetrahedral meshes with open faces, by the networks of irregular tetrahedral meshes that have some closed faces, by the networks of irregular tetrahedral meshes of open faces, by the irregular tetrahedral mesh networks that have some closed faces, by the open-faced regular octahedral mesh networks, by the regular octahedral mesh networks that have some closed faces, by the open-faced irregular octahedral mesh networks , by the networks of irregular octahedral meshes that have some closed faces, by the networks of regular hexahedral meshes with open faces, by the networks of regular hexahedral meshes that have some closed faces, by the networks of irregular hexahedral meshes with open faces, by the networks of irregular hexahedral meshes that have some closed faces, by the networks of regular dodecahedral meshes with open faces, by the networks of regular dodecahedral meshes that have some closed faces, by the networks of irregular dodecahedral meshes with open faces, by the networks of irregular dodecahedral meshes that have some closed faces, therefore the networks of regular icosahedral meshes with open faces, by the networks of regular isosahedral meshes that have certain closed faces, by the networks of irregular icosahedral meshes with open faces, by the networks of irregular icosahedral meshes that have some closed faces, by their variants curved and by their combinations. Other solid three-dimensional networks can be used.

On the other hand, in some embodiments, advantageously and according to the invention, the three-dimensional solid network comprises at least one mesh open in at least three different non-collinear directions - in particular three directions orthogonal to each other. In particular, in some embodiments, advantageously and according to the invention, each open mesh of said three-dimensional solid network is open in at least three different non-collinear directions - in particular three directions orthogonal to each other. In this way, at least one fluid can flow in these three directions through and / or within the part.

In some embodiments, advantageously and according to the invention, a solid three-dimensional network is selected from the group formed by the networks having meshes that have openings in each of the faces of the polyhedral meshes.

On the other hand, in some embodiments, advantageously and according to the invention, each opening of each face of a polyhedral mesh of the three-dimensional solid network presents an area greater than the total area of the face that incorporates it. Thus, the circulation of fluid through these openings is promoted. The solid walls are dimensioned to respect the minimum mechanical characteristics desired for the piece.

On the other hand, in some embodiments, advantageously and according to the invention, as dielectric materials, air and a solid dielectric material capable of being printed by three-dimensional printing according to said three-dimensional solid network are selected. The nesting structure thus comprises a solid three-dimensional network of a solid dielectric material capable of being printed by three-dimensional printing, the meshes of which incorporate air cells and are open in at least two different directions - in particular in three orthogonal directions and / or on each of the faces of these meshes-. Obviously, nothing prevents the provision of other dielectric materials, as a variant or in combination.

On the other hand, in some embodiments, advantageously and according to the invention, at least one of said solid-state dielectric materials is selected from the group formed by metal oxides, carbides, borides, nitrides , by fluorides, by silicides, by titanates, by sulfides, by synthetic polymers and their mixtures. Obviously, nothing prevents the provision of other dielectric materials, as a variant or in combination.

On the other hand, in some embodiments, advantageously and according to the invention, a three-dimensional printing selected from the group formed by additive manufacturing (AM), by additive layered manufacturing (ALM), by selective laser fusion is used. (SLM), by selective laser sintering (SLS), by selective hot sintering (SHS), by melt deposit molding (FDM or DIW), by multiple jet molding (MJM), by stereolithography (SLA ), by manufacturing laminated objects (LOM) and by film transfer imaging (FTI).

On the other hand, in some embodiments, advantageously and according to the invention, said nesting structure is arranged in such a way that each homogeneous zone of one of said dielectric materials has a maximum dimension less than a value amax = a in any direction of space. . Ao, in which a is a real number less than 10 -in particular less than 1, in particular less than 0.1-, and Ao is the wavelength of an electromagnetic radiation for which a dielectric part according to the invention is adapted. Furthermore, the dielectric part has a dimension in any direction of space that is greater than this value amax. In other words, for a predetermined mean frequency fo.

where n is the index of a medium in which the dielectric part is intended to be used, and C is the speed of light in vacuum.

In particular, in some embodiments, advantageously and according to the invention, Ao being between 3 mm and 3 m, amax is between 50 µm and 50 cm.

Thus, in some embodiments of a method according to the invention, an interlocking structure of the dielectric materials is selected according to a solid three-dimensional network:

- adapted to allow manufacturing of the dielectric part by three-dimensional printing,

- which forms a spatial distribution of dielectric materials adapted to obtain an effective relative dielectric permissiveness tensor [£ r] and / or an effective relative magnetic permeability tensor [jr], - in which each homogeneous zone of one of said materials Dielectrics have, for a predetermined wavelength Ao in any direction of space, a maximum dimension less than amax = a. Ao, where a is a real number less than 10, -in particular less than 1, in particular less than 0.1-.

Thus, the invention makes it possible to obtain a dielectric part that has an effective relative dielectric permissiveness tensor [£ r] and / or an effective relative magnetic permeability tensor [jr] that can be determined (s) and from which others characteristics, in particular characteristics selected from the group of mechanical characteristics, thermal characteristics, optical characteristics, and fluidic characteristics (incorporation and / or circulation of at least one fluid within the part) can be also precisely controlled and selected. The invention makes it possible in particular to obtain a dielectric part that incorporates at least one dielectric fluid in a precisely controlled manner, which can be uniform in at least one part of the part, which forms a circulation and / or enclosure circuit of each dielectric fluid, meanwhile.

A dielectric part according to the invention may, on the other hand, have completely closed and hermetic peripheral walls for each fluid dielectric material it contains; or, on the contrary, present peripheral walls at least partially open that allow the circulation of at least one fluid dielectric material through the dielectric piece; even have peripheral walls completely open. Each dielectric material in the fluid state can be incorporated into the three-dimensional solid network, in particular by suction, injection (in particular vacuum injection), pumping, etc.

The invention also makes it possible in particular to precisely control the mechanical characteristics and / or the thermal characteristics and / or the optical characteristics and / or the dielectric characteristics and / or the magnetic characteristics of a dielectric part.

The mechanical characteristics are determined by those of the three-dimensional solid network and the choice of each solid dielectric material.

The thermal characteristics are determined by that of each of the dielectric materials that make up the dielectric part according to the invention, and in particular by an appropriate choice of at least one dielectric material in a fluid state.

The optical characteristics are determined by the choice of the optical properties of each of the dielectric materials that make up the part according to the invention.

The effective dielectric characteristics are determined by the choice of the dielectric characteristics of each of the dielectric materials that make up the part according to the invention, and by the choice of the interlocking structure of these dielectric materials.

It should be noted in particular in this regard that the provision of large area openings in the nesting structure may imply that Maxwell Garnett's theory of effective heterogeneous materials does not provide a reliable evaluation of the effective relative dielectric permissivity tensor, if the conditions of application of this theory are not fulfilled. In this case, other evaluation techniques can be used, such as that described in "Electromagnetic parameter retrieval from inhomogeneous metamaterials", DR Smith et al., Phys. Rev. E 71, 036617, 2005.

The effective magnetic characteristics are determined by the choice of the magnetic permeability of each of the dielectric materials that make up the part according to the invention, by the choice of the interlocking structure of these dielectric materials.

A dielectric part according to the invention can serve as a transmitter and / or receiver of an electromagnetic and / or electrical and / or magnetic field. It can be used particularly advantageously in the field of hyperfrequencies (frequencies higher than 100 MHz, in particular between 1 GHz and 10 GHz), for example (non-limiting list) as:

- antenna substrate (this term also encompasses coating substrates called “superstrates”),

- dielectric lens,

- radome,

- substrate or insulator for hyperfrequency electrical circuit,

- dielectric resonator in a dielectric resonator filter.

The invention also relates to a manufacturing process and a dielectric part and their applications characterized in combination by all or part of the characteristics mentioned above or below.

Other objectives, characteristics, and advantages of the invention will appear upon reading the following description, given by way of non-limitation and referring to the attached figures in which:

- figure 1 is a synoptic diagram illustrating the main stages of a process according to the invention,

Figures 2 to 10 are perspective diagrams illustrating different examples of elemental mesh of a three-dimensional solid network of a dielectric piece according to the invention,

Figures 11 to 15 are perspective diagrams illustrating different embodiments of three-dimensional solid networks of a dielectric part according to the invention,

Figures 16 and 17 are front and profile diagrams of an example of a dielectric part according to the invention in general disk shape.

In a method according to the invention as represented in figure 1, in a first step 11, at least a desired value of at least one relative electromagnetic constant is selected for a dielectric part to be manufactured, and at least one frequency fo and / or at least one wavelength Ao of electromagnetic radiation for which the dielectric part must be adapted.

An effective desired value of at least one relative electromagnetic constant can be chosen, this effective desired value being the same at all points of said dielectric part according to the invention.

At each point M (x, y, z) of the volume of the dielectric part, at least a desired value of relative dielectric permissiveness £ r (x, y, z) and / or relative magnetic permeability | Jr ( x, y, z) appropriate for this point. Thus, a gradient of relative dielectric permittivity £ r (x, y, z) and / or relative magnetic permeability jr (x, y, z) can be defined.

Furthermore, the dielectric part can have an anisotropy for at least one relative electromagnetic constant. Thus, at each point M, at least one desired value of at least one relative electromagnetic constant can also be dependent on a direction of propagation and / or incidence of electromagnetic radiation, such that at least one vector (x , yz), (x, y, z) can be defined for at least one relative electromagnetic constant at this point M. The values of the components of this vector can be constant for all points of the volume of the dielectric part, or on the contrary, it varies in the volume of the dielectric piece forming a gradient for the corresponding relative electromagnetic constant.

Thus, a spatial distribution tensor of at least one relative electromagnetic constant (an effective dielectric permittivity tensor [£ r] and / or an effective relative magnetic permeability tensor [jr]) can be selected in the volume of the dielectric part .

In general, the radiation or electromagnetic and / or electric and / or magnetic field for which the dielectric part must be adapted is of hyperfrequency, that is, it has a frequency greater than 100 MHz.

In a second stage 12, at least one dielectric material in solid state and at least one dielectric material in fluid state (gaseous and / or liquid) constituting the dielectric part to be manufactured is selected. Each dielectric material has a known value £ „, jri of the relative electromagnetic constant (s), the known values £„, jri being different for the different dielectric materials and selected so that it can be obtaining each desired value - in particular each spatial distribution tensor of said at least one relative electromagnetic constant - by interweaving the different dielectric materials.

In particular, for each relative electromagnetic constant whose effective value it is desired to control at any point in the dielectric part, at least one first dielectric material is selected that has a known value of this relative electromagnetic constant that is lower than each desired value for this electromagnetic constant. relative, and at least one second dielectric material having a known value of this relative electromagnetic constant greater than each desired value for this relative electromagnetic constant. In some advantageous embodiments, a dielectric material in the fluid state is selected as the first dielectric material (that is, with a known value lower than each desired value), and a dielectric material in the solid state as the second dielectric material (that is, known value greater than each desired value). In most situations, it is possible to select only a single dielectric material in the solid state, and a single dielectric material in the fluid state, in particular in the gaseous state, in particular air. However, nothing prevents selecting a plurality of dielectric materials in the solid state and / or a plurality of dielectric materials in the fluid state, of similar or different natures, for example a dielectric material in the gaseous state and a dielectric material in the liquid state.

On the other hand, each solid-state dielectric material is selected so that it can be printed by three-dimensional printing according to a three-dimensional solid network constituted by meshes of said solid-state dielectric material. Said network formed by polyhedral and / or polygonal meshes (in the sense indicated above) printed by three-dimensional printing allows to control very precisely and very finely the effective value of at least one -in particular of each- relative electromagnetic constant at any point of dielectric part and in any direction.

Furthermore, advantageously, each dielectric material in solid state is selected in such a way that it can be printed by three-dimensional printing according to a three-dimensional solid network that has meshes open in at least two different non-collinear directions, that is to say that they form an angle not null different from 180 °. In this way, a fluid circulation (in open or closed circuit) can be obtained inside the dielectric part.

In some advantageous embodiments, at least one of said solid-state dielectric materials is selected from the group formed by inorganic ceramics (group of metal oxides, carbides, borides, nitrides, fluorides, silicides, titanates, sulphides and their mixtures), and by synthetic polymers (selected in particular from the group of thermoplastics (for example from the group of polyfluorocarbons such as PTFE, polyamides , FEP (Perfluoro ethylene propylene), PFA (perfluoroalkoxy), of polyolefins such as polyethylenes, PPO® (polyphenylene oxide), of hydrocarbon resins, of photopolymers), and their mixtures. On the other hand Advantageously and according to the invention, at least one of said dielectric materials in the fluid state is atmospheric air.

In some embodiments, a dielectric part according to the invention can be manufactured in such a way as to present a totally hermetic peripheral outer casing containing each dielectric material in a fluid state that remains incorporated within the dielectric part without being able to escape from it. Thus, at least one gaseous and / or liquid composition can be trapped inside a dielectric part according to the invention, within the three-dimensional solid network formed by each dielectric material in solid state. Said gaseous and / or liquid composition is selected for example from the group of heat transfer fluids, conductive liquids, electrolytes, liquid crystals, atmospheric gases, ionized gases. In some embodiments, a dielectric part according to the invention can be manufactured in such a way that it has peripheral passage openings for at least one gaseous and / or liquid composition that can circulate at least in part inside the dielectric part. through the solid three-dimensional network formed by each dielectric material in solid state. In particular, the three-dimensional solid network can be of the type that forms open meshes at the periphery of the dielectric piece, this three-dimensional solid network being arranged in a volume of gaseous and / or liquid composition that fills the interior of this three-dimensional solid network. For example, said volume of gaseous and / or liquid composition is the atmospheric environment that prevails around the dielectric part, for example the Earth's atmosphere or the space vacuum.

In some embodiments, at least one dielectric material in the fluid state is a composition in the liquid state, in particular selected from the group consisting of aqueous compositions, hydroalcoholic compositions, oils, solvents, and liquid crystals. In some embodiments, at least one dielectric material in the fluid state is a composition in the gaseous state, in particular selected from the group consisting of atmospheric gases and ionized gases (plasmas).

In a third stage 13, the characteristics of the nesting structure of the different dielectric materials are determined in order to obtain each desired value of at least one relative electromagnetic constant, that is, in particular the proportions of the different dielectric materials that make up the part. dielectric to be used to obtain each desired value of at least one relative electromagnetic constant. For this, one can use in particular a theory known per se such as the theory of effective means heterogeneous, for example Maxwell Garnett's theory (see for example http://en.wikipedia.org/wiki/Effective_medium_approximations) or any other theory possibly applicable to this case.

In this third stage 13, a maximum dimension amax of each homogeneous area of each dielectric material in any direction of space is also determined, according to the value of the wavelength Ao and / or the predetermined average value frequency fo,

where a is a real number less than 10 -in particular less than 1, in particular less than 0.1-, n is the index of a medium in which the dielectric part is intended to be used, and C is the speed of light in vacuum. Indeed, this maximum dimension amax allows in particular a sufficient application of the theory of heterogeneous effective media, so that the dielectric part effectively has effective values of at least one electromagnetic constant corresponding to the interlocking of the different dielectric materials . In other words, the dielectric part is equivalent to a homogeneous material in its effects against electromagnetic radiation.

In particular, in some embodiments, advantageously and according to the invention, Ao being between 3 mm and 3 m, amax is between 50 pm and 50 cm.

In the fourth stage 14, some additional mechanical characteristics and / or thermal characteristics and / or optical characteristics desired for the dielectric part to be manufactured are selected, taking into account however the mechanical and / or thermal and / or optical properties of the Dielectric materials selected above.

In the fifth stage 15, a nesting structure is selected that, on the one hand, corresponds to the proportions and the maximum amax dimension previously determined and, on the other hand, allows to obtain the previously selected mechanical and / or thermal and / or optical characteristics . In particular, the geometry and topology of said three-dimensional solid network is selected. This selection can be made with the aid of a computer-aided design program that allows simulating said mechanical and / or thermal and / or optical characteristics.

For example, said solid three-dimensional network is selected from the group formed by the hexahedral mesh networks, in particular parallelepipedic -particularly cubic- regular ones with open faces, by the hexahedral mesh networks -in particular parallelepipedic, in particular cubic- regular that have some closed faces, by the hexahedral mesh networks - in particular parallelepiped, in particular cubic - irregular with open faces, by the hexahedral mesh networks - in particular parallelepiped, in particular cubic - irregular that have some closed faces, by the open-sided regular tetrahedral mesh networks, by regular tetrahedral mesh networks that have some closed faces, by open-sided irregular tetrahedral mesh networks, by irregular tetrahedral mesh networks that have some closed faces, by regular octahedral open-sided meshes, by oc meshes regular tahedrons that have some closed faces, by open-faced irregular octahedral mesh networks, by irregular octahedral mesh networks that have some closed faces, by open-faced regular hexahedral mesh networks, by regular hexahedral mesh networks that have some closed faces, by open-faced irregular hexahedral mesh networks, by irregular hexahedral mesh networks that have some closed faces, by open-faced regular dodecahedral mesh networks, by regular dodecahedral mesh networks that have some closed faces, by open-faced irregular dodecahedral mesh networks, by irregular dodecahedral mesh networks that have some closed faces, by open-faced regular icosahedral mesh networks, by regular icosahedral mesh networks that have some faces closed, by the networks of irregular icosahedral meshes s with open faces, by the networks of irregular icosahedral meshes that have some closed faces, by their curved variants and by their combinations. Other solid three-dimensional networks can be used.

On the other hand, in some embodiments, the three-dimensional solid network comprises at least one mesh open in at least three different directions - in particular three directions orthogonal to each other. In particular, in some embodiments, advantageously and according to the invention, each open mesh of said three-dimensional solid network is open in at least three different directions - in particular three directions orthogonal to each other. In this way, at least one fluid can circulate in these three directions through and / or within the part.

In the sixth stage 16, the dielectric part thus determined is manufactured by three-dimensional printing. For this, any three-dimensional printing technology can be considered, depending on the nature of the selected dielectric materials and the three-dimensional solid network. For example, you can use a three-dimensional printing selected from the group (non-limiting list) formed by additive manufacturing (AM), by the Additive Layered Manufacturing (ALM), by selective laser melting (SLM), by selective laser sintering (SLS), by selective hot sintering (SHS), by melt deposit molding (FDM or DIW), by Multiple Jet Molding (MJM), by Stereolithography (SLA), by Laminate Object Fabrication (LOM) and by Film Transfer Imaging (FTI).

In an optional seventh step 17, it is possible to incorporate at least one dielectric material in a fluid state into the solid three-dimensional network, for example by suction or injection under pressure. It is also possible, depending on the applications, to seal all or part of the periphery of the dielectric part by a hermetic envelope, for example by a coating of a hermetic curable composition applied to the periphery of the three-dimensional solid network, in particular by tempering or deposit on the surface, afterwards being the object of a hardening stage.

Figure 2 is an example of a hexahedral elemental mesh 20 that can be used to form a uniform three-dimensional solid network by repeating this elemental mesh 20 formed by a solid dielectric material. The elementary mesh 20 is, in the example, a parallelepiped the six faces of which have rectangular openings, the opposite faces having openings of identical dimensions and the adjacent faces having openings whose dimensions along the common edges are also identical. This elementary parallelepipedic mesh 20 has a height a1, a length a2 and a width a3. The opening of the longitudinal vertical faces 21 has a height b1 and a length b2. The opening of the lateral vertical faces 22 has a width b3 and a height b4. The opening of the longitudinal horizontal faces 23 has a width b5 and a length b6. In the example shown, b4 = b1, b5 = b3, and b6 = b2. However, nothing prevents the provision of openings of different dimensions between the adjacent faces, that is to say b4 * b1 and / or b5 * b3 and / or b6 * b2.

Figure 11 is an example of a three-dimensional solid network that can be obtained from this elementary parallelepipedic mesh that, in the example, is cubic, a1 = a2 = a3 = a and b1 = b2 = b3 = b4 = b5 = b6 = b. Figure 12 is another example of a three-dimensional solid network, which differs from the previous one by the fact that the elementary mesh is offset by a / 2 between two adjacent XY planes of mesh of the network. Figures 13 and 15 are other examples of a three-dimensional solid network corresponding to the elementary mesh 20 of Figure 2 with different values of a1, a2, a3 and of b4 = b1, b5 = b3, and b6 = b2.

Figure 3 represents another example of hexahedral (cubic) elemental mesh 30 with truncated angles 34. Figure 4 represents another example of elementary mesh 40 similar to figure 3 inscribed in a cube but in which the faces of the cube have median edges 45 crossed in their center. Figure 5 represents another example of elementary mesh 50 inscribed in a cube whose faces have median edges 55 crossed in their center and angles 54 truncated to the centers of the main edges of the faces of the cube circumscribed in mesh 50, these being 54 truncated angles formed by solid walls. Figure 6 represents another example of elementary mesh 60 inscribed in a cube whose faces have two concentric circular edges 66, 67 joined by four median edges 65 that form radii.

Figure 7 represents a tetrahedral elemental mesh 70. Figure 8 represents an octahedral elemental mesh 80. Figure 9 depicts a dodecahedral elemental mesh 90. Figure 10 represents an elemental icosahedral mesh 100. These different elementary meshes can be used to generate solid three-dimensional networks, with some of their faces eventually solid, with openings of dimensions that can be variable or identical, with angles that can be truncated or not, etc.

These different geometric and topological variants make it possible to vary the mechanical and / or thermal and / or optical and / or dielectric and / or magnetic characteristics of the dielectric piece thus obtained. The nesting structures thus formed can be manufactured by three-dimensional printing.

The dielectric pieces obtained are formed by a solid three-dimensional network whose elemental meshes have open faces in at least two different non-collinear directions, which in particular allows fluid circulation inside the dielectric piece.

Figures 16 and 17 represent an example of a dielectric part according to the invention in the general shape of a disk formed by a network of the type shown in figure 13, the direction X of figure 13 being orthogonal to the main face 110 of the disk, the disk comprising three layers 111 of identical meshes with open rectangular faces, and therefore four levels 112 of rectangular faces oriented in the Y, Z directions of Figure 13. The piece comprises at the height of each level 112 of faces oriented in the Y, Z directions, a peripheral circular edge 113 to which the edges of the peripheral meshes are attached.

As a variant not represented, it is possible to form within said dielectric piece one or more circuits containing one or more dielectric fluids, sealing some of the faces of the mesh of the network. In particular, an open circuit can be formed which leads to the periphery of the dielectric part and / or on one of its main faces to form one or more inlet ports and / or one or more outlet ports. In particular, it is also possible to form several independent circuits isolated from one another.

Examples

The effective electromagnetic constants of mesh networks of dielectric pieces according to the invention are evaluated by the method described in the publication "Electromagnetic parameter retrieval from inhomogeneous metamaterials", DR Smith et al., Phys. Rev. E 71, 036617, 2005.

The working frequency fü is equal to 4 GHz.

Table 1 below provides the results obtained for the networks of Figures 11 and 13 with an open-face parallelepipedic mesh structure, with a ceramic (alumina) that has a relative permissiveness £ r = 10.6 and a relative permeability | Jr = 1 as a solid dielectric material, and air £ r = 1, | Jr = 1, as a fluid dielectric material.

Table 1

As can be seen in the example of figure 11, effective electromagnetic constant values are obtained that are the same in all directions, while the structure of the selected network is not isotropic and allows in particular to vary the mechanical characteristics and / or thermals of the dielectric part according to the invention in the different directions of space.

In the example of figure 13, it is observed that it is possible to obtain different values of the dielectric permissiveness in the different directions of space by selecting an appropriate structure of the network.

A manufacturing process according to the invention can be the subject of very numerous embodiment variants. In particular, it is possible to use several printed solid-state dielectric materials simultaneously, a first dielectric material forming a three-dimensional solid network the meshes of which are at least partially filled by another solid-state dielectric material. It is also possible to use only dielectric materials in solid state imbricated by three-dimensional printing, with at least one of the dielectric materials in solid state forming said solid three-dimensional network having meshes filled with at least one other dielectric material in solid state.

A dielectric part according to the invention can act as an emitter and / or receiver of an electromagnetic and / or electric and / or magnetic field and can also be the subject of numerous variant embodiments and various applications. In particular, it can be used advantageously in the field of hyperfrequencies (frequencies greater than 100 MHz, in particular between 1 GHz and 10 GHz), for example (non-limiting list) as:

- antenna substrate (this term also encompasses coating substrates called “superstrates”),

- dielectric lens,

- radome,

- substrate or insulator for hyperfrequency electrical circuit,

- dielectric resonator in a dielectric resonator filter.

Claims (18)

1. Manufacturing process of a dielectric part in which several dielectric materials are interwoven, of which at least one is in a solid state, said dielectric materials having at least one relative electromagnetic constant er, | Jr of different values , characterized by that: - this nesting is carried out by selecting: ◦ (15) an interlocking structure of said dielectric materials formed by a three-dimensional solid network constituted by a repetition in all directions of the mesh space (20, 30, 40, 50, 60, 70, 80, 90, 100) of at least one, in solid state, of said dielectric materials, and in which each homogeneous zone of one of said dielectric materials has in any direction of space a maximum dimension less than a value amax = a. Aü, in which a is a real number less than 1Ü, and A ^ü is a wavelength of electromagnetic radiation for which the dielectric part must be adapted, ◦ and (12) dielectric materials adapted to allow manufacture of the three-dimensional solid network by three-dimensional printing of each solid dielectric material, - the dielectric part is manufactured (16) by three-dimensional printing of the three-dimensional solid network, such that the dielectric part has at least one tensor [er], [jr] determined of at least one relative electromagnetic constant er, jr. 2. Process according to claim 1, characterized in that at least one of the dielectric materials is selected in the fluid state, and a three-dimensional solid network having at least one mesh (20, 30, 40, 50, 60, 70, 80, 90, 100) open in at least two different directions forming a non-zero angle different from 180 ° to each other. Method according to one of claims 1 or 2, characterized in that at least one of the dielectric materials is selected in the fluid state, and a solid three-dimensional network of which all the meshes (20, 30, 40, 50, 60 , 70, 80, 90, 100) non-peripheral are open in at least two different directions of space forming a non-zero angle different from 180 ° to each other. Method according to one of Claims 1 to 3, characterized in that a three-dimensional solid network is selected from which all non-peripheral meshes (20, 30, 40, 50, 60, 70, 80, 90, 100) have a same geometric motif. Method according to one of Claims 1 to 4, characterized in that a three-dimensional solid network is selected from the group formed by the networks having meshes (20, 30, 40, 50, 60, 70, 80, 90, 100 ) that have solid walls arranged included in faces of straight polyhedral meshes and by networks that have solid walls arranged included in faces of curved polyhedral meshes. 6. Method according to claim 5, characterized in that a three-dimensional solid network is selected from the group formed by the networks that have meshes (2Ü, 30, 40, 50, 60, 70, 80, 90, 100) that have some openings in each of the faces of polyhedral meshes. Method according to one of claims 1 to 6, characterized in that a solid three-dimensional network is selected from the group formed by the networks having meshes (20, 30, 40, 50, 60, 70, 80, 90, 100 ) that have solid walls arranged included in faces of polyhedral meshes and at least one opening in at least two different faces of the non-peripheral polyhedral meshes, and because each opening of each face of a polyhedral mesh of the solid network Three-dimensional presents an area greater than the total area of the face that incorporates it. Method according to one of claims 1 to 7, characterized in that air and a solid dielectric material capable of being printed by three-dimensional printing according to said three-dimensional solid network are selected as dielectric materials. 9. Process according to one of claims 1 to 8, characterized in that at least one of said dielectric materials in solid state is selected from the group consisting of metal oxides, carbides, borides, nitrides, fluorides, silicides, titanates, sulfides, synthetic polymers, and their mixtures. 10. Dielectric part comprising an imbrication of several dielectric materials of which one at least minus is in solid state, and having at least one relative electromagnetic constant er, | Jr of different values, characterized in that said nesting is made according to a nesting structure of said dielectric materials formed by a solid three-dimensional network: - constituted by a repetition in all directions of the mesh space (20, 30, 40, 50, 60, 70, 80, 90, 100) of at least one, in solid state, of said dielectric materials, - in which each homogeneous zone of one of said dielectric materials has, in any direction of space, a maximum dimension less than a value amax = a. Aü, in which a is a real number less than 10, and Aü is a wavelength of an electromagnetic radiation for which the dielectric part is adapted, - printed by three-dimensional printing, such that it has at least one tensor [er], [jr] determined from at least one relative electromagnetic constant er, jr. Piece according to claim 10, characterized in that at least one of the dielectric materials is in a fluid state, and at least one mesh (20, 30, 4ü, 50, 60, 70, 80, 90, 100) of said solid three-dimensional network is open in at least two different directions forming a non-zero angle different from 180 ° to each other. 12. Part according to one of claims 10 or 11, characterized in that at least one of the dielectric materials is in a fluid state, and all the meshes (20, 30, 40, 50, 60, 70, 80, 90, 100 ) non-peripheral of said solid three-dimensional network are open in at least two different directions of space that form a non-zero angle different from 180 ° to each other. Part according to one of claims 10 to 12, characterized in that all non-peripheral meshes (20, 30, 40, 50, 60, 70, 80, 90, 100) of said solid three-dimensional network have the same geometric pattern. Piece according to one of claims 10 to 13, characterized in that said three-dimensional solid network is selected from the group formed by the networks having meshes (20, 30, 40, 50, 60, 70, 80, 90, 100 ) having solid walls arranged included in faces of straight polyhedral meshes and by nets having meshes having solid walls arranged included in faces of curved polyhedral meshes. Piece according to claim 14, characterized in that said three-dimensional solid network is selected from the group formed by the networks that have polyhedral meshes (20, 30, 40, 50, 60, 70, 80, 90, 100) that have some openings on each of its faces. Part according to one of claims 10 to 15, characterized in that said three-dimensional solid network is selected from the group formed by the networks having meshes (20, 30, 40, 50, 60, 70, 80, 90, 100 ) that have solid walls arranged included in faces of polyhedral meshes and at least one opening in at least two different faces of the non-peripheral polyhedral meshes, and because each opening of each face of a polyhedral mesh of the solid network Three-dimensional presents an area greater than the total area of the face that incorporates it. Part according to one of Claims 10 to 16, characterized in that it comprises, as dielectric materials, air and a solid dielectric material printed by three-dimensional printing according to said three-dimensional solid network. 18. Part according to one of claims 10 to 17, characterized in that at least one of said dielectric materials in solid state is selected from the group formed by metal oxides, carbides, borides, nitrides, fluorides, silicides, titanates, sulfides, synthetic polymers, and their mixtures.