Artificial dielectric material and focusing lens made thereof

Abstract

Provided herein is an artificial dielectric material comprising a plurality of sheets of dielectric material and a plurality of conductive elements disposed in holes formed in the sheets of dielectric material, wherein each conductive element is a three-dimensional object consisting of a plurality of side panels connected to a central support and configured to form a conductor surface surrounding an empty space. Also provided are conductive elements and focusing lenses comprising artificial dielectric materials and conductive elements, as well as methods of making these materials and methods of using them. Artificial dielectric materials, lenses, and their manufacture can provide desirable dielectric and radio wave focusing properties compared to known materials and manufacturing advantages.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority from New Zealand Patent Application No. 760969 filed on 17 January 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to artificial dielectric materials containing conductive elements and focusing lenses for electromagnetic waves made therefrom. Background Art

[0004] The modern mobile communication market requires multi-beam antennas that produce narrow beams and operate in different frequency bands. Focusing dielectric lenses are the main part of the most efficient multi-beam antennas. The diameter of the focusing lens must be several wavelengths of the electromagnetic wave propagating through the lens to produce a narrow beam, so some lenses of multi-beam antennas used for mobile communications have a diameter greater than 1m. This lens made of commonly used dielectric materials is too heavy, so a lot of research has been done to make a lightweight and low-loss lens that provides ideal focusing lens performance.

[0005] The best-known lightweight artificial dielectric materials are made of a mixture of randomly oriented conductive parts and non-conductive parts made of lightweight dielectric materials. It is very difficult to make a uniform material with the desired dielectric properties by randomly mixing conductive and non-conductive parts, so the focusing lens is the most expensive component of a multi-beam antenna. People have been developing such materials to improve the performance of the focusing lens and reduce its cost.

[0006] US Patent 8518537 B2 describes a lightweight artificial dielectric material comprising a plurality of randomly oriented small elements of lightweight dielectric material, such as polyethylene foam, each element containing conductive fibers within.

[0007] Patent application US 2018 / 0034160 A1 describes a lightweight artificial dielectric material comprising a plurality of randomly oriented small multilayer elements of lightweight dielectric material containing thin conductive patches between the layers. The document describes such multilayer elements as providing a dielectric constant greater than that provided by elements containing conductive fibers.

[0008] Patent application US 2018 / 0279202 A1 describes other types of lightweight artificial dielectric materials, including a plurality of randomly oriented small elements. One described material includes small multilayer elements of lightweight dielectric material that contain thin conductive sheets between the layers.

[0009] All of the lightweight artificial dielectric materials mentioned above are made of a random mix of small components. The material includes many stages and is expensive because of the need to eliminate metal-to-metal contacts within the material that can cause passive intermodulation distortion.

[0010] Random mixing provides isotropic properties of the final material composed of small elements, but some applications require dielectric materials with anisotropic properties. For example, a cylindrical lens made of anisotropic dielectric materials can reduce the depolarization of electromagnetic waves passing through the cylindrical lens and improve the cross-polarization ratio of multi-beam antennas (US Patent 9819094 B2). A cylindrical lens made of isotropic artificial dielectric materials produces depolarization of electromagnetic waves passing through such a lens, so an antenna including such a lens may suffer from high cross-polarization levels.

[0011] New Zealand patent application 752904 filed on 25 April 2019 describes a lightweight artificial dielectric material that provides anisotropic properties and is suitable for making cylindrical lenses. The material consists of short conductive tubes having thin walls and placed inside a lightweight dielectric material. The tubes are placed in layers. One layer comprises a sheet of lightweight dielectric material containing a plurality of holes. The lightweight dielectric material may be a foamed polymer. The tubes are placed in holes made of lightweight dielectric material, containing air inside. The layers containing the tubes are separated by layers of lightweight dielectric material that do not contain tubes. The axes of all the conductive tubes are perpendicular to the layers.

[0012] For electromagnetic waves propagating along the axis of the tube, the dielectric constant (ε) of such a structure can be up to 2.5, but for electromagnetic waves propagating in the perpendicular direction, ε is much smaller. It is known that this undesirable property of artificial dielectric materials arises due to the anisotropic properties of the tube.

[0013] There is a need to provide an improved lightweight artificial dielectric material for use in making devices such as focusing lenses and antennas for radio communications. The provided material must be easy to manufacture and have repeatable properties. Summary of the invention

[0014] In a first aspect of the present invention, an artificial dielectric material is provided, comprising a plurality of sheets of dielectric material and a plurality of conductive elements arranged in holes formed in the sheets of dielectric material, wherein each conductive element is a three-dimensional object consisting of side panels connected to a central support and arranged to form a conductive surface surrounding a blank space.

[0015] The side panels may be arranged to be perpendicular or non-perpendicular to the support member.

[0016] The artificial dielectric material may have at least one surface of the conductive element covered by a dielectric film. Alternatively, at least one surface of the conductive element is covered by a conductive film.

[0017] The artificial dielectric material may have holes in the dielectric material, the holes containing protrusions, the protrusions being disposed in the gaps separating the outer portions of the conductive elements.

[0018] The artificial dielectric material may have cross-shaped slots or holes in the central support and / or the one or more side plates.

[0019] The axes of the conductive elements of the artificial dielectric material are preferably oriented in at least two different directions, preferably in at least two orthogonal directions.

[0020] The conductive elements of the artificial dielectric material may have at least two different shapes.

[0021] The conductive element may have the shape of half of a hollow sphere including grooves cut through the surface of the sphere to provide side plates.

[0022] The dielectric material is preferably a foamed polymer, most preferably polyethylene, polystyrene, polypropylene, polyurethane, silicon or polytetrafluoroethylene.

[0023] The conductive elements arranged in one layer may form a square lattice, providing equal distances between adjacent tubes arranged in the same row or column. Alternatively, the conductive elements arranged in one layer may form a honeycomb (hexagonal) lattice, providing equal distances between any adjacent elements.

[0024] The axes of the conductive elements arranged in one layer may point in the same direction. Such axes of the conductive elements arranged in one layer may be perpendicular to the layer. Such axes of the conductive elements arranged in one layer may be parallel to the layer.

[0025] The axes of some conductive elements disposed in a layer may be perpendicular to the layer, while the axes of other conductive elements may be parallel to the layer. The axes of conductive elements parallel to the layer may point in different directions.

[0026] According to another aspect of the present invention, there is provided a focusing lens comprising an artificial dielectric material comprising an electrically conductive element according to the present invention.

[0027] The focusing lens may include multiple layers, wherein the conductive elements of each layer form a sunflower (radial circle) lattice. The focusing lens may include at least one circle of a layer containing conductive elements, the axis of which is parallel to the layer and parallel to the circle. The focusing lens may include at least one circle of a layer containing conductive elements, the axis of which is parallel to the layer and perpendicular to the circle.

[0028] The focusing lens may include a layer having conductive elements whose axes are only perpendicular to the layer; and a layer having conductive elements whose axes are only parallel to the layer.

[0029] The focusing lens may include a layer containing conductive elements whose axes are parallel only to the layer, the layer being oriented perpendicular to the axes of conductive elements of another layer whose axes are parallel to the layer.

[0030] The focusing lens may include each layer comprising a conductive element wherein the axis of the conductive element is perpendicular to the layer, and a conductive element wherein the axis of the conductive element is parallel to the layer.

[0031] The focusing lens may include a conductive element having an axis parallel to the layers and displaced on the even layers, the even layers being perpendicular to the axis of the conductive element, and having an axis parallel to the layers and displaced on the odd layers.

[0032] The focusing lens may include each layer comprising a circle of conductive elements, wherein the circle has an axis perpendicular to the layer, and a circle of conductive elements, wherein the circle has an axis parallel to the layer.

[0033] The focusing lens may include a dielectric rod positioned along a longitudinal axis of the focusing lens.

[0034] The focusing lens may be cylindrical or may be spherical.

[0035] Another aspect of the invention provides a method for manufacturing an artificial dielectric material according to the invention, the method comprising placing conductive elements in a plurality of sheets of dielectric material and stacking the sheets together, wherein the axes of the conductive elements are oriented in at least two different directions.

[0036] In this method, the conductive elements may be placed in pre-existing holes in a sheet of dielectric material.

[0037] In the method, sheets of dielectric material containing conductive elements may be separated from sheets of dielectric material without conductive elements.

[0038] A sheet of dielectric material containing conductive elements may include holes that do not extend through the thickness of the sheet.

[0039] The method may include the step of bending the outer portion of the conductive element as it is placed into the sheet of dielectric material.

[0040] Another aspect of the invention provides a conductive element for an artificial dielectric material, the element comprising side plates connected to a central support and arranged to form a conductive surface surrounding a void space.

[0041] The side panels may be arranged perpendicularly or non-perpendicularly to the support portion.

[0042] The side panels may be connected to the outer regions of the central support member.

[0043] Another aspect of the present invention provides a method of focusing radio waves using a focusing lens according to an embodiment of the present invention.

[0044] By providing the above-described artificial dielectric material, the present invention overcomes at least in some way the disadvantages of known lightweight artificial dielectric materials and provides a lightweight artificial dielectric material that is less dependent on the direction and polarization of electromagnetic waves propagating through the material.

[0045] Electromagnetic waves propagating through artificial dielectric materials containing conductive elements excite circular currents flowing on the conductive elements, so the magnetic permeability of such materials is less than 1. This effect was described many years ago (WEKock Metallic delay lenses. / / Bell System Technical Journal, v.27, pp.58-82, January 1948.) When electromagnetic waves propagate to a square or hexagonal lattice of conductive tubes in the direction of the tube axis, the delay factor (n) does not depend on the polarization, because any polarization will excite the same circular current. When electromagnetic waves propagate to a square or hexagonal lattice of conductive tubes in a perpendicular direction, the axis n of the tube does depend on the polarization. When the magnetic field of the electromagnetic wave is oriented parallel to the axis of the conductive tube, the largest circular current flows on the wall of the conductive tube in a direction perpendicular to the axis of the conductive tube. Therefore, the magnetic permeability of this polarization is significantly smaller than that of other polarizations, and the delay factor n is also smaller than that of other polarizations. The delay factor n of this polarization can be increased by reducing the distance between the tubes arranged in a layer. Increasing the capacity between the tubes arranged in a layer increases the dielectric constant of the artificial dielectric material. Thus, known artificial dielectric materials can provide very small differences between n for any polarization of an electromagnetic wave propagating in a direction perpendicular to the axis of the conducting tube, but cannot provide the same n for other directions of the electromagnetic wave.

[0046] Since n depends on the angle between the direction of the electromagnetic wave passing through the material and the tube axis, such artificial dielectric materials are not suitable for many applications that require an isotropic dielectric material that provides the same value of n for any direction and polarization of the electromagnetic wave. For example, a spherical Luneburg lens must be made of an isotropic dielectric material that has the same n for any direction and polarization of the electromagnetic wave in order to preserve the polarization of the electromagnetic wave passing through the spherical lens. Therefore, it is necessary to create an artificial dielectric material whose n is less dependent on the direction and polarization of the electromagnetic wave passing through the material than the known materials described in NZ752904. At the same time, the manufacture of such a material must be simpler than the manufacture of known lightweight artificial materials, which are made by randomly mixing small elements containing conductive elements isolated from each other.

[0047] The focusing properties of artificial dielectric materials such as tubes depend on the retardation coefficient, where μ is the magnetic permeability. When an electromagnetic wave passes through a known lightweight artificial dielectric material, this induces a current in the conductive material, for which μ is less than 1. The largest circular current flows in a conductive material, such as the wall of a tube, in a direction perpendicular to the axis of the conductive tube when the magnetic field of the electromagnetic wave is parallel to the axis of the conductive tube. Therefore, μ for this polarization is smaller than for the other polarizations, and the delay factor n is also smaller than for the other polarizations. Artificial dielectric materials containing short tubes are subject to this effect, so it is necessary to find other shapes of conductive elements to increase μ and the delay factor n.

[0048] The artificial dielectric material according to the invention provides a lightweight artificial dielectric material that is less dependent on the direction and polarization of electromagnetic waves propagating through the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In further describing the present invention, reference is made, by way of example only, to the accompanying drawings, in which:

[0050] Figure 1a-1c shows a perspective view of a short conductive tube according to the prior art;

[0051] Figure 2a-2c shows a perspective view of a conductive element according to an embodiment of the present invention;

[0052] Figure 3a-3d shows perspective views of conductive elements according to various embodiments of the present invention;

[0053] Figure 3e and 3f A top view and a cross-sectional view of a conductive element according to an embodiment of the present invention are respectively shown;

[0054] Figure 4a and 4b shows a perspective view of a conductive element according to an embodiment of the present invention;

[0055] Figure 5 shows a top view of a conductive element disposed in a hole formed in a dielectric foam sheet according to an embodiment of the present invention;

[0056] Figure 6a-6h A series of top views of an embodiment of the present invention are shown, wherein Figure 3b The conductive elements shown are arranged in a layer and form different structures;

[0057] Figure 7a-7c The top views of the first layer, the second layer and the third layer of the cylindrical lens according to the present invention are respectively shown;

[0058] Figure 7d shows a cross section of a cylindrical lens according to the present invention, the cylindrical lens comprising a lens corresponding to Figure 7a-7c Six floors;

[0059] Figure 8a shows a cross-sectional view of a cylindrical lens according to an embodiment of the present invention;

[0060] Figure 8b shows a cross-sectional view of a cylindrical lens according to an embodiment of the present invention;

[0061] Figure 9a A top view of a first layer of cylindrical lenses according to an embodiment of the present invention is shown;

[0062] Figure 9b shows a cross-sectional view of a cylindrical lens according to an embodiment of the present invention;

[0063] Fig.9c shows a top view of a second layer of cylindrical lenses according to an embodiment of the present invention;

[0064] Fig.10a A top view of a first layer of cylindrical lenses according to an embodiment of the present invention is shown;

[0065] Fig.10b shows a cross-sectional view of a cylindrical lens according to an embodiment of the present invention;

[0066] Fig.10c Shown according to Fig.10b A top view of the second layer of the cylindrical lens of the embodiment of the present invention shown;

[0067] Fig.10d Shown according to Fig.10b A top view of the third layer of the cylindrical lens of the embodiment of the present invention shown;

[0068] Fig.11a A top view of a first layer of cylindrical lenses according to an embodiment of the present invention is shown;

[0069] Fig.11b shows a cross-sectional view of a cylindrical lens according to an embodiment of the present invention;

[0070] Fig.11c Shown according to Fig.11b A top view of the second layer of the cylindrical lens of the embodiment of the present invention shown;

[0071] Fig.12a A top view of a first layer of cylindrical lenses including a central rod according to an embodiment of the present invention is shown;

[0072] Figure 12b shows a cross-sectional view of a cylindrical lens including a central rod according to an embodiment of the present invention;

[0073] Fig.12c Shown according to Figure 12bA top view of a second layer of cylindrical lenses including a central rod according to an embodiment of the present invention shown;

[0074] Fig.13a A top view of a first layer of cylindrical lenses according to an embodiment of the present invention is shown;

[0075] Fig.13b shows a cross-sectional view of a cylindrical lens according to an embodiment of the present invention;

[0076] Fig.14a shows a top view of a spherical lens according to an embodiment of the present invention;

[0077] Fig.14b shows a cross-sectional view of a spherical lens according to an embodiment of the present invention;

[0078] In all the drawings, section line AA is used to indicate a section in the same set of corresponding drawings. Fig.10a The part indicated in Fig.10b The first layer in . DETAILED DESCRIPTION

[0079] As described and shown in the accompanying drawings, the artificial dielectric material includes a plurality of conductive particles, described herein as conductive elements, which are disposed in holes formed in a sheet of lightweight dielectric material. Each conductive element is a three-dimensional object consisting of thin parts (described herein as side plates) directly connected to an intermediate part (described herein as a central support) and forming the outer contour of the conductive element, which surrounds the empty space formed in the interior of the conductive element. Typically, the conductive element is made of a piece of suitable conductive metal, such as aluminum, which is bent into the desired shape. The metal can also be copper, nickel, silver or gold.

[0080] Alternatively, a thin sheet of lightweight, resilient dielectric material formed into the desired shape may be coated with a thin layer of conductive material to form the conductive element.

[0081] Some embodiments of the conductive element include a central support member and side panels disposed at a horizontal plane, the side panels being connected to an outer contour or region of the central support member and disposed at other planes, the other planes being rotated, for example, 30-90 degrees from the horizontal plane. Thus, the relationship between the central support member and the side panels may be vertical or non-vertical. The outer contour of the central support member may be a polygon, such as a triangle, square, hexagon, or octagon. The central support member may include a hole. In the examples shown in the figures, the outer contour is generally shown as a hexagon only as an example.

[0082] Other embodiments of the conductive element may include side panels that are not flat and are more solid than conductive elements with flat side panels. For example, the conductive element may be half of a hollow sphere, such as Figure 5As shown in Figs. 5a and 5b, it has a groove arranged on its diameter. Therefore, this conductive element has an arcuate conductive element. The conductive material may have at least one surface of the conductive element covered by a dielectric film.

[0083] The conductive elements are placed in layers. One layer comprises a sheet of lightweight dielectric material containing a plurality of holes filled with the conductive elements. The lightweight dielectric material may be a foamed polymer. The foamed polymer is preferably made of a material selected from the group consisting of polyethylene, polystyrene, polypropylene, polyurethane, silicon and polytetrafluoroethylene. The layers containing the conductive elements are separated by layers of dielectric material without conductive elements. The separation layer may be a foamed polymer or a thin dielectric film. The separation layer may also comprise a plurality of holes having a diameter smaller than the diameter of the holes for the conductive material to provide air circulation through the lightweight dielectric material.

[0084] Two samples of artificial dielectric materials were fabricated to compare the properties of the proposed material with known materials. The first sample was made of a known material containing Figure 1a The second sample consisted of a short conductive tube containing Figures 2a to 2c The conductive element shown is made of a suggested material and comprises: a flat middle part or central support 1, which is arranged in a horizontal plane, and four side plate parts 2, which are connected to the outer contour of the central support and are arranged in a plane rotated 90 degrees from the horizontal plane, as shown in FIG. Figure 2a The two artificial dielectric material samples have the same size and contain the same number of conductive elements. Compared with the known artificial dielectric material containing a short conductive tube, when the magnetic field of the electromagnetic wave is parallel to the axis of the conductive tube, Figure 2a The magnetic measurements of the artificial dielectric material shown containing the conducting elements do show an increase in μ. The measured sample of the known artificial dielectric material has μ = 0.69. Figure 1b shows a circular current flowing on the wall of a conductive tube when the magnetic field of an electromagnetic wave is parallel to the axis of the tube.

[0085] The measured sample of the artificial dielectric material according to the present invention has μ = 0.85, because the circular current cannot flow on the side plates 2 separated by the gap when the magnetic field of the electromagnetic wave is parallel to the axis of the conductive element and flows only on the central support 1, as Figure 2b shown.

[0086] When the magnetic field of the electromagnetic wave is perpendicular to the axis of the conductive tube and the conductive element, the performance difference is smaller. It is known that the measured sample of artificial dielectric material has μ = 0.83. Figure 1c It shows a circular current flowing on the wall of the conductive tube when the magnetic field of the electromagnetic wave is perpendicular to the axis of the conductive tube.The measured sample of the artificial dielectric material according to the present invention has μ = 0.86. Figure 2c It shows circular currents flowing on the side plates 2 of the conductive element when the magnetic field of the electromagnetic wave is parallel to the substrate. The separation of the side plates 2 from each other reduces such circular currents, but does not eliminate them.

[0087] Both materials have almost the same ε, so the artificial dielectric material according to the present invention has a larger retardation coefficient n, which is less dependent on the polarization of the electromagnetic wave.

[0088] Another embodiment of the present invention is Figure 3a , in which a cross groove 3 is formed in the central support 11 of the conductive element. Such a groove limits the circular current to flow in the central area of ​​the central support, so that the circular current can only flow along the outer contour of the central support 11.

[0089] Figure 3b Another embodiment of the present invention is shown in FIG. 1 , in which the conductive element has a central support 5 and six side plate portions 6 in a hexagonal shape. Figure 2a to Figure 2c The side plate 2 is narrow, so when the magnetic field of the electromagnetic wave is parallel to the central support 5, the circular current flowing on the side plate 6 is smaller than that on the Figures 2a to 2c The current flowing on the side plate 2 of the corresponding material is shown.

[0090] Another embodiment of the present invention is Figure 3c The conductive element has a rectangular planar central support 7 arranged in a horizontal plane and two side plate portions 8 connected to the outer contour of the central support and arranged at 90 degrees relative to the horizontal plane of the central support.

[0091] Another embodiment of the present invention is Figure 3d The conductive element has a square planar central support 9 arranged in a horizontal plane and four side plate portions 10 connected to the outer contour of the central support and arranged at an angle of 60 degrees relative to the horizontal plane of the central support 9.

[0092] Another embodiment of the present invention is respectively Figure 3e and 3f The conductive element is half of a hollow sphere, as shown in Figure 1. Figure 3e As shown, grooves are provided on its diameter, which divide the hemisphere into side plate parts 12. The central support 11 and the four side plates 12 are not flat, so this element is more Figure 3a and 3b The components shown are more robust.

[0093] Another embodiment of the present invention is Figure 4a, in which a thin sheet of lightweight elastic dielectric material 13 formed into the desired shape is coated with a thin layer or film of conductive material 14 to form a conductive element comprising a central support 15 and two side plates 16. This coating can be carried out by electrodeposition or rolling of the film. The thickness of the conductive element made in this way is only a few microns, so that such an element is very light. Such an element can be stamped from a sheet of dielectric film, coated with a conductive layer and bent into the desired shape after stamping. The bending can be carried out during the installation of the conductive element into the hole.

[0094] Another embodiment of the present invention is Figure 4b , wherein a sheet 17 of lightweight elastic dielectric material formed into a desired shape is coated with a thin layer of conductive material 18 to form a conductive element comprising a central support 19 and four side plates 20. A cross slot 21 is formed on the side plates 20 of the conductive element.

[0095] Alternatively, the conductive material may be similarly coated with a film or layer of dielectric material to form a structure with Figure 4a and Figure 4b The conductive elements shown are similar conductive elements but are made by a different process, where the dielectric is provided by deposition or rolling.

[0096] Another embodiment of the present invention is Figure 5 As shown in Figure 3d The conductive element is arranged in a hole 22 made of a sheet of lightweight dielectric material 23. The hole 22 contains protrusions 24 that fix the position of the side plates of the conductive element.

[0097] The conductive elements placed in adjacent layers may be placed one on top of the other on the same axis. The adjacent layers may be shifted relative to each other so that the conductive elements placed in the adjacent layers have different axes.

[0098] The conductive elements can be arranged with different axis directions. The axes of some conductive elements are perpendicular to the layers, while the axes of other conductive elements are parallel to the layers. The conductive elements with axes parallel to the layers can have their axes arranged perpendicular to each other. Thus, the axes of the conductive elements can have three orthogonal directions. Therefore, the dielectric properties of the artificial dielectric material according to the present invention are less dependent on the direction and polarization of the electromagnetic waves passing through the material.

[0099] Conductive elements placed in a layer may have the same axial orientation or different orientations. Layers containing conductive elements placed on top of each other may have the same structure or different structures. Different layers may include conductive elements with different spacings in each layer. For example, adjacent layers or sheets of the same size may have different numbers of radial circles with conductive elements arranged in radial circles to increase the distance between the circles. Similarly, for a honeycomb lattice arrangement, the distance between adjacent conductive elements in the same layer may vary.

[0100] The properties of the provided artificial dielectric material depend on the orientation of the conductive elements and the distances between the conductive elements and between the layers. Thus, the provided artificial dielectric material comprises conductive elements with different axis orientations in the layers and layers with different structures, providing an opportunity to achieve desired dielectric properties compared to known materials. For example, the dependence of the delay coefficient n on the orientation and polarization of the electromagnetic wave passing through the provided artificial dielectric material can be reduced. Thus, the provided artificial dielectric material can be used to manufacture a variety of focusing lenses and antennas.

[0101] Several embodiments of the present invention are shown in Figure 6a-6h Among them Figure 3b The conductive elements shown are arranged in one layer to form different layer structures.

[0102] Figure 6a A top view of a layer comprising conductive elements placed row by row is shown, wherein the axes of the conductive elements are perpendicular to the layer and the distances between adjacent rows of conductive elements and the distances between adjacent conductive elements of a row are equal.

[0103] Figure 6b A top view of a layer comprising conductive elements placed in rows with their axes perpendicular to the layer is shown. The rows are shifted by half the distance between adjacent conductive elements placed in a row, and the distance between any adjacent conductive elements is equal.

[0104] Figure 6c A top view of a layer comprising conductive elements placed in rows is shown, wherein the axes of all conductive elements are parallel to the layer and to each other.

[0105] Figure 6d A top view of a layer comprising conductive elements placed in rows with their axes parallel to the layer and to each other is shown. The rows are shifted by half the distance between adjacent conductive elements placed in a row.

[0106] Figure 6e A top view of a layer comprising rows of conductive elements is shown, wherein the axes of the conductive elements are arranged alternately, wherein half of the conductive elements are perpendicular to the layer and the axes of the other half of the conductive elements are parallel to the layer. Each row comprises conductive elements with axes perpendicular to the layer and conductive elements with axes parallel to the layer.

[0107] Figure 6f A top view of a layer comprising conductive elements arranged in rows is shown, wherein the axes of the conductive elements are arranged alternately, wherein half of the conductive elements have axes perpendicular to the layer and the other half have axes parallel to the layer. Each row comprises conductive elements with axes perpendicular to the layer and conductive elements with axes parallel to the layer. Adjacent rows are shifted by half the distance between adjacent rows.

[0108] Figure 6g A top view of a layer comprising conductive elements arranged in rows is shown, wherein one third of the conductive elements have axes perpendicular to the layer and the other conductive elements have axes parallel to the layer. Of the conductive elements with axes parallel to the layer, half of these conductive elements have axes perpendicular to the axes of the other half of the conductive elements having axes parallel to the axis of the layer.

[0109] Figure 6h A top view of a layer comprising conductive elements arranged in rows is shown, wherein one third of the conductive elements have axes perpendicular to the layer and the other conductive elements have axes parallel to the layer. Of the conductive elements having axes parallel to the layer, half of these conductive elements have axes perpendicular to the axes of the other half of the conductive elements having axes parallel to the axis of the layer. Adjacent rows are shifted by half the distance between adjacent rows.

[0110] like Figure 2a-5 Conductive elements in other shapes as shown in b may also be Figure 6a-6h Set up as shown.

[0111] Several embodiments of cylindrical lenses and layers formed of artificial dielectric materials according to the present invention that can form cylindrical lenses are described below.

[0112] The conductive elements placed in a layer can form various lattices of conductive elements in order to adopt suitable properties. These lattices include square structures (lattices) providing equal distances between adjacent conductive elements arranged in the same row or column, such as Figure 6a and 6c Alternatively, the conductive elements placed in a layer form a honeycomb or hexagonal structure (lattice) to provide equal distances between any adjacent conductive elements, such as Figure 7a-7c Alternatively, the conductive elements placed in a layer form a sunflower structure lattice consisting of radial circles, such as Fig.10a shown.

[0113] Figure 7a A top view of the first layer of cylindrical lenses is shown, wherein Figure 3b The conductive elements shown in FIG. 1 are placed in rows and the axes of the conductive elements are perpendicular to the layer. The distances between adjacent conductive elements are equal.

[0114] Figure 7b A top view of the second layer of cylindrical lenses is shown, wherein Figure 3b The conductive elements shown in FIG. 1 are placed in rows and the axes of the conductive elements are parallel to the layer and oriented along the rows. The distances between adjacent conductive elements are equal.

[0115] Figure 7c A top view of the third layer of cylindrical lenses is shown, wherein Figure 3bThe conductive elements shown in FIG. 1 are placed in rows and the axes of the conductive elements are parallel to the layer and perpendicular to the rows. The distances between adjacent conductive elements are equal.

[0116] Figure 7d A cross section of a cylindrical lens comprising six layers of sheet material is shown, the sheet comprising Figure 3b . The first and fourth layers are equal. The second and fifth layers are equal. The third and sixth layers are equal. Thus, this lens is assembled from three different layers. The conductive elements are arranged in holes made in the foam dielectric sheets 31-33. The sheets 31-33 containing conductive elements are separated by a sheet 34 without conductive elements.

[0117] Figure 8a A cross section of a cylindrical lens comprising six layers of sheet material is shown, the sheet comprising Figure 3b The conductive element shown in FIG. 1 , wherein the hole shape made in the foam dielectric sheets 35-37 is formed on one surface so as not to penetrate the foam dielectric on the other side, thereby providing additional support for the conductive element. The first layer and the fourth layer are equal. The second layer and the fifth layer are equal. The third layer and the sixth layer are equal. Therefore, this lens is assembled from three different layers.

[0118] Figure 8b Another embodiment of a cross section of a cylindrical lens is shown, the cylindrical lens comprising six layers of sheets including Figure 3b The conductive elements shown in FIG. Figure 8a Additional holes 25 are formed in the dielectric foam sheet 35-37, penetrating the other side of the dielectric foam to provide air circulation through the lens.

[0119] Furthermore, holes can be formed in the dielectric material so that the conductive elements can penetrate both sides of the layer. In this case, the sheets containing the conductive elements are separated by an intermediate sheet of dielectric material that does not contain the conductive elements.

[0120] For other applications and end-use requirements, the conductive elements placed in the layers may form other structures, and the lens may include other numbers and a variety of different layers.

[0121] Another embodiment of the present invention is Figure 9a-9c , where each layer of a cylindrical lens comprises a plurality of conductive elements arranged in a circle around the center of a cylinder. Each circle contains conductive elements that are oriented identically, with axes that are either parallel or perpendicular to the layer, but the circles alternate between two orthogonal orientations, such as Figure 9a and 9c shown.

[0122] Figure 9aA top view of the first layer is shown. The axes of the conductive elements placed on the first circle of the outer contour of the layer closest to the lens are parallel to the layer and perpendicular to the tangent of the circle. The axes of the conductive elements placed on the second circle from the outer contour of the lens are perpendicular to the layer.

[0123] Fig.9c A top view of the second layer is shown. The axis of the conductive element placed on the first circle of the outer contour of the layer from the lens is parallel to the layer and parallel to the tangent of the circle. The axis of the conductive element placed on the second circle of the outer contour of the layer from the lens is perpendicular to the layer.

[0124] Figure 9b A cross section of a cylindrical lens comprising four layers of conductive elements is shown. The first and second layers have conductive elements of different orientations placed on alternating circles. The first and third layers are equal. The second and fourth layers are equal. Thus, this lens is assembled from two different layers.

[0125] Another embodiment of the present invention is Figures 10a to 10d , where each layer of the cylindrical lens includes a plurality of conductive elements arranged in a circle.

[0126] Fig.10a A top view of the first layer of a cylindrical lens is shown, where the conductive elements are arranged in a circle and the axis of the elements is perpendicular to the layer. A top view of the second layer is shown Fig.10c As shown in FIG. 1 , the conductive elements are arranged in a circle, and the axis of the element is parallel to the layer and perpendicular to the tangent of the circle. The top view of the third layer is shown in FIG. Fig.10d As shown, in which the conductive elements are arranged in a circle, the axis of the element is parallel to the layer and parallel to the tangent of the circle.

[0127] Fig.10b A cross section of a cylindrical lens comprising six layers of conductive elements is shown. The first and fourth layers are equal and correspond to Fig.10a The second and fifth layers are equal and correspond to Fig.10c The third and sixth layers are equal and correspond to Fig.10d . Therefore, this lens is assembled from three different layers.

[0128] Another embodiment of the present invention is Figures 11a to 11c , where each layer of the cylindrical lenses comprises a plurality of conductive elements arranged in a circle and where the conductive elements have two orthogonal directions of their axes.

[0129] Fig.11a shows a top view of a first layer of a cylindrical lens, wherein the conductive elements are arranged in radial circles, with alternating conductive elements positioned orthogonally, similar to Figure 6e and 6fThe conductive elements are arranged in circles, each circle containing conductive elements with axes perpendicular to the layer and conductive elements with axes parallel to the layer and parallel to the tangent of the circle.

[0130] Fig.11c shows a top view of the second layer of a cylindrical lens, where the conductive elements are arranged in radial circles, with alternating conductive elements positioned orthogonally, similar to Figure 6e and 6f The conductive elements are arranged in circles, each circle containing conductive elements with axes perpendicular to the layer and conductive elements with axes parallel to the layer and perpendicular to the tangent of the circle.

[0131] Fig.11b A cross section of a cylindrical lens comprising four layers of conductive elements is shown. The conductive elements of the first layer, where the axis is parallel to the layers, are also parallel to the tangent of the circle in which the conductive elements are placed. The conductive elements of the second layer, where the axis is parallel to the layers, are also parallel to the tangent of the circle in which the conductive elements are placed. The first and third layers are equal. The second and fourth layers are equal. Thus, this lens is assembled from two different layers.

[0132] Another embodiment of the present invention is Figures 12a to 12c , wherein a cylindrical lens made of a provided artificial dielectric material includes a central rod 26 made of dielectric material and placed in the middle (central axis) of the cylindrical lens. This rod increases the retardation factor n in the middle of the cylindrical lens and provides mechanical support for the lightweight dielectric sheet forming the lens. Fig.12a and 12c The structure of the layers of the cylindrical lens shown in Fig.11a and 11c The structure of the layers of the cylindrical lenses shown in FIG.

[0133] Another embodiment of the present invention is Fig.13a and 13b , where each layer of the cylindrical lens comprises a plurality of conductive elements arranged in a circle and having three orthogonal directions of their axes.

[0134] Fig.13aA top view of a layer of such cylindrical lenses is shown. The axes of the conductive elements placed in the first circle from the outer contour of the lens layer are parallel to the layer and parallel to or aligned with the tangent of the circle. The axes of the conductive elements placed in the second circle from the outer contour of the lens are parallel to the layer and perpendicular to the tangent of the circle. The axes of the conductive elements placed in the third circle from the outer contour of the lens layer are perpendicular to the layer. The axes of the conductive elements forming the first, fourth and seventh circles are parallel to or aligned with the tangent of the respective circles. The axes of the conductive elements forming the second, fifth and eighth circles are perpendicular to the tangent of the respective circles. The axes of the conductive elements forming the third, sixth and ninth circles are perpendicular to the layer and are shorter than the other conductive elements forming the layer.

[0135] Fig.13b Shown is the inclusion Fig.13a Cross section of a cylindrical lens of four equal layers shown in . Thus, this lens is assembled from only one type of layer. However, in addition to the three variations of the orientation of the conductive material in the single layer, different layers can also be used.

[0136] The cylindrical lens includes Figure 3b The conductive elements shown are only for the purpose of simplifying the drawing. Other figures, e.g. Figure 2a-4b The conductive elements shown in , as well as other configurations not depicted, can be used in any of the above-described cylindrical lenses and artificial dielectric material layers that constitute the cylindrical lenses.

[0137] A group of focusing lenses that can be made of the provided artificial dielectric material is not limited to the above embodiments. The focusing lens layer can also be formed by other structures. For example, by Figure 6g and 6h The structure shown, wherein the axes of the conductive elements forming each row point in three orthogonal directions. If the conductive elements forming a layer of cylindrical lenses are placed in radial circles, each circle may contain conductive elements with axes in three orthogonal directions. Such a lens can be assembled from only one layer. The conductive elements forming the layers may be the same or have different sizes. The distances between the conductive elements forming the layers may be equal and form a structure that provides a permanent delay coefficient n along the layer. The distances between the conductive elements forming the layers may increase continuously towards the outer contour of the lens. The distances between the conductive elements forming the layers may be unequal and form multiple areas that provide different delay coefficients n along the layer. New Zealand patent application 752904 Figure 5Such a layer as shown in -8 is formed by a tube having an axis perpendicular to the layer. Since the retardation coefficient n depends on the angle between the direction of the electromagnetic wave passing through the material and the axis of the tube, such an artificial dielectric material is not suitable for many applications requiring an isotropic dielectric material to provide the same value of the retardation coefficient n for any direction and polarization of the electromagnetic wave. The provided artificial dielectric material comprising a conductive element having axes in three orthogonal directions is suitable for the manufacture of a spherical Luneburg lens which must be made of an isotropic dielectric material having the same retardation coefficient n for any direction and polarization of the electromagnetic wave.

[0138] Fig.14a A top view of a spherical lens according to an embodiment of the present invention is shown. The lens is assembled from circular foam dielectric sheets containing conductive elements. Foam dielectric sheets 41-47 with different diameters are stacked together and form an outer profile of the lens that is generally similar to a sphere shape.

[0139] Fig.14b FIG. 4 is a cross-sectional view of a spherical lens according to an embodiment of the present invention. The central portion of the spherical lens comprises a foam dielectric sheet 41, which comprises a dielectric foam sheet 41. Fig.13a The conductive elements are arranged as shown. The sheets 42-47 have a gradually decreasing diameter and fewer conductive elements than the sheet 41, however, the configuration of the particles of the layers is similar to Fig.14b Same as depicted in .

[0140] Such a spherical lens can effectively form a beam with a half-power beam width of 20-40 degrees. A large spherical lens forming a narrower beam increases the distance between the conductive elements toward the outer contour of the sphere.

[0141] The invention also relates to a method for manufacturing an artificial dielectric material, which in turn can be used to produce a lens consisting of multiple layers of artificial dielectric material. The method comprises placing conductive elements in holes in a plurality of sheets of dielectric material and stacking the sheets together, wherein the sheets of dielectric material containing conductive elements are separated by sheets of dielectric material not containing conductive elements, and wherein the axes of the conductive elements are oriented in at least two different directions. As an alternative, the sheets not containing dielectric material can be omitted, and the sheets containing conductive elements can have holes that do not pass through the thickness of the sheets. In this way, the conductive elements of each layer can be kept separate as desired.

[0142] The conductive element may be placed in a pre-existing hole in the sheet of dielectric material. Furthermore, the manufacturing process may require bending the outer portion of the conductive element as it is placed into the pre-existing hole in the sheet of dielectric material. Alternatively, the conductive element may be placed into the hole already pre-formed into its desired shape at the time of assembly.

[0143] The invention also relates to a method for focusing radio waves using a focusing lens according to the invention. Such a lens may be spherical or cylindrical, or may have another geometric shape. The use of such a focusing lens comprising an artificial dielectric material according to the invention and a conductive element allows focusing radio waves with less dependence on the direction and polarization of the electromagnetic waves.

[0144] Although some preferred aspects of the present invention have been described by way of example, it should be appreciated that modifications and / or improvements may be made without departing from the scope of the invention as claimed in this specification.

[0145] The terms include or comprise if and when used herein should be interpreted as being non-exclusive, ie the expression “consists of or includes”.

[0146] It should be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms part of the common general knowledge in the art in New Zealand or any other country.

Claims

1. An artificial dielectric material comprising a plurality of sheets of foamed polymer dielectric material and a plurality of conductive elements arranged in holes made in the plurality of sheets of foamed polymer dielectric material, wherein the plurality of sheets of foamed polymer dielectric material form multiple layers, each conductive element being a three-dimensional object, the three-dimensional object being composed of a plurality of side panels connected to a central support member but separated from each other and arranged to form a conductive surface surrounding an empty space.

2. The artificial dielectric material according to claim 1, characterized in that The side panels are arranged to be perpendicular or non-perpendicular to the central support member.

3. The artificial dielectric material according to claim 1, characterized in that At least one surface of the conductive element is covered by a dielectric film.

4. The artificial dielectric material according to claim 1, characterized in that At least one surface of the conductive element is covered by a conductive film.

5. The artificial dielectric material according to claim 1, characterized in that The holes in the plurality of sheets of foamed polymer dielectric material include protrusions disposed in gaps separating exterior portions of the conductive elements.

6. The artificial dielectric material according to claim 1, characterized in that The central support of the conductive element includes a cross slot or hole.

7. The artificial dielectric material according to claim 1, characterized in that The axes of the conductive elements are oriented in at least two different directions.

8. The artificial dielectric material according to claim 7, characterized in that The at least two different directions are orthogonal directions.

9. The artificial dielectric material according to claim 1, characterized in that The conductive element has at least two different shapes.

10. The artificial dielectric material according to claim 1, characterized in that The conductive element has the shape of a half hollow sphere having grooves cut through the surface of the sphere to provide side plates.

11. The artificial dielectric material according to claim 1, characterized in that The plurality of foamed polymer dielectric material sheets are made of a material selected from the group consisting of polyethylene, polystyrene, polypropylene, polyurethane, silicon and polytetrafluoroethylene.

12. The artificial dielectric material according to claim 1, characterized in that The conductive elements arranged in a layer form a square lattice, providing equal distances between adjacent conductive elements arranged in the same row or column.

13. The artificial dielectric material according to claim 1, characterized in that The conductive elements arranged in a layer form a hexagonal lattice, providing equal distance between any adjacent elements.

14. The artificial dielectric material according to claim 1, characterized in that The axes of the conductive elements arranged in one layer point in the same direction.

15. The artificial dielectric material according to claim 1, characterized in that The axes of the conductive elements arranged in a layer are perpendicular to the layer.

16. The artificial dielectric material according to claim 1, characterized in that The axes of the conductive elements arranged in a layer are parallel to the layer.

17. The artificial dielectric material according to claim 1, characterized in that Some of the conductive elements arranged in a layer have axes perpendicular to the layer, while other conductive elements have axes parallel to the layer.

18. The artificial dielectric material according to claim 17, characterized in that The axes of the conductive elements parallel to the layers point in different directions.

19. A focusing lens comprising the artificial dielectric material according to any one of claims 1 to 18.

20. The focusing lens according to claim 19, characterized in that The conductive elements of each layer form a lattice of radial circles.

21. The focusing lens according to claim 19, characterized in that Included are layers having conductive elements with axes only perpendicular to the layer, and layers having conductive elements with axes only parallel to the layer.

22. The focusing lens according to claim 19, characterized in that The axes of the conductive elements of the layer, wherein the layer contains conductive elements with axes parallel only to the layer, are perpendicular to the axes of the conductive elements of another layer, wherein the other layer contains conductive elements with axes parallel to the layer.

23. The focusing lens according to claim 19, characterized in that Each layer contains: conductive elements having an axis perpendicular to the layer, and conductive elements having an axis parallel to the layer.

24. The focusing lens according to claim 19, wherein: The axes of the conductive elements parallel to the layers and displaced at the even-numbered layers are perpendicular to the axes of the conductive elements parallel to the layers and displaced at the odd-numbered layers.

25. The focusing lens according to claim 20, characterized in that Each layer contains radial circles of conductive elements perpendicular to the axis of the layer, and radial circles of conductive elements parallel to the axis of the layer.

26. The focusing lens according to claim 20, characterized in that At least one radial circle contains a conductive element whose axis is parallel to the layer and parallel to the radial circle.

27. The focusing lens according to claim 20, characterized in that At least one radial circle contains a conductive element having an axis parallel to the layer and perpendicular to the radial circle.

28. The focusing lens according to any one of claims 19 to 27, characterized in that The dielectric rod is placed along the longitudinal axis of the focusing lens.

29. The focusing lens according to any one of claims 19 to 27, characterized in that The lens is cylindrical.

30. The focusing lens according to any one of claims 19 to 27, characterized in that The lens is spherical.

31. A method for manufacturing the artificial dielectric material according to claim 1, characterized in that: The method includes placing a conductive element in a plurality of sheets of foamed polymer dielectric material and stacking the plurality of sheets of foamed polymer dielectric material together, wherein axes of the conductive element are oriented in at least two different directions.

32. The method according to claim 31, characterized in that The conductive elements are placed in pre-existing holes in the plurality of sheets of foamed polymer dielectric material.

33. The method according to claim 31 or 32, characterized in that The plurality of sheets of foamed polymer dielectric material containing the conductive elements are separated by sheets of foamed polymer dielectric material that do not contain conductive elements.

34. The method according to claim 31 or 32, characterized in that The plurality of sheets of foamed polymer dielectric material comprising the conductive elements include holes that do not extend through a thickness of the plurality of sheets of foamed polymer dielectric material.

35. The method according to claim 31 or 32, characterized in that The outer portion of the conductive element is bent while being placed into the plurality of sheets of foamed polymer dielectric material.

36. A conductive element for use in the artificial dielectric material of claim 1, the element comprising a plurality of side panels connected to a central support and arranged to form a conductive surface surrounding a void space.

37. The conductive element according to claim 36, characterized in that The side panels are arranged to be perpendicular or non-perpendicular to the central support member.

38. The conductive element according to claim 36 or 37, characterized in that: The side panels are connected to the outer regions of the central support member.

39. A method of focusing radio waves using the focusing lens as claimed in any one of claims 19 to 30.

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