Guide element for an antenna and method for producing such guide element

Abstract

The invention relates to a guide element for an antenna for a fill level meter, wherein the guide element is composed of a dielectric material and is used for forming, guiding and emitting electromagnetic radiation. The guide element has a permittivity course that changes over the spatial expansion of the guide element for specifically forming the electromagnetic radiation, the course being implemented by a spatial distribution of the material density of the dielectric material, wherein the material density is defined as one portion of dielectric material per elementary cell of a given size. Furthermore, the invention relates to a method for producing a guide element.

Claims

1. A guide element for an antenna for a fill level meter, wherein the guide element as a whole has a one-piece construction formed of a single dielectric material and is used for forming, guiding and emitting electromagnetic radiation, wherein the guide element has a variation in permittivity over a spatial expansion of the guide element for specifically forming the electromagnetic radiation, variations in material density of the single dielectric material producing said variation in permittivity, wherein the material density is defined as one portion of the dielectric material per elementary cell of a given size.

2. The guide element according to claim 1, wherein the dielectric material is arranged in an irregular structure or in a regular structure at least in a part of the elementary cells.

3. The guide element according to claim 2, wherein the permittivity is steady or unsteady at least over a part of the spatial expansion of the guide element.

4. The guide element according to claim 3, wherein the irregular structure or the regular structure is a Voronoi tessellation or a Delaunay tessellation of a space of the elementary cells.

5. The guide element according to claim 4, wherein the spatial distribution of the material density of the dielectric material is implemented by varying a wall thickness of the cells, of which the Voronoi tessellation or the Delaunay tessellation of the elementary cells consist.

6. The guide element according to claim 4, wherein the spatial distribution of the material density of the dielectric material is implemented by varying a density of the cells, of which the Voronoi tessellation or the Delaunay tessellation of the elementary cells are formed, while retaining a wall thickness of cells.

7. The guide element according to claim 2, wherein the irregular structure and the regular structure are formed by adjacent structure cells, wherein the size of the structure cells is variable in dependence on the size of the elementary cell in which the respective structure cells are located.

8. The guide element according to claim 1, wherein the guide element is produced using a generative manufacturing method.

9. The guide element according to claim 1, wherein the size of the elementary cell in one volume range is dependent on a gradient of the permittivity in the one volume range.

10. The guide element according to claim 9, wherein at least one of: the size of the elementary cell is a smallest for a volume range that has a largest gradient of the permittivity; and the size of the elementary cell is a largest for a volume range that has a smallest gradient of the permittivity.

11. The guide element according to claim 9, wherein: the size of the elementary cell, in the statistical mean, averaged over the volume of the guide element, is larger where the gradient of the permittivity is smaller; and the size of the elementary cell, in the statistical mean, averaged over the volume of the guide element, is smaller where the gradient of the permittivity is larger.

12. The guide element according to claim 7, wherein, in the statistical mean, the structure cells in larger elementary cells are greater than the structure cells in smaller elementary cells.

13. The guide element according to claim 9, wherein the size of the elementary cell in the one volume range is dependent on a maximum gradient of the permittivity in the one volume range.

14. A method for producing a guide element for an antenna for a fill level meter, wherein the guide element as a whole has a one-piece construction that is formed of a single dielectric material and forms, forwards, and emits a supplied electromagnetic radiation, the method comprising: first, specifying a permittivity variation in a spatial expansion of the guide element that is attuned to use of the guide element for an antenna for a fill level meter, then, specifying a corresponding variation of material density of the single dielectric material for producing the specified permittivity variation, then, determining a structure that implements the c of the single dielectric material, and then, producing the structure determined using a generative manufacturing method so as to have said one-piece construction formed of the single dielectric material having the specified permittivity variation.

15. The method according to claim 14, wherein the specifying the structure that implements the material density distribution comprises dividing the guide element into elementary cells, wherein the size of adjacent ones of the elementary cells can vary among one another.

16. The method according to claim 15, wherein the size of the elementary cell in one volume range is dependent on a gradient of the permittivity in the one volume range.

17. The method according to claim 16, wherein at least one of: the size of the elementary cells is chosen as a smallest for a volume range that has a largest gradient of the permittivity variation; and the size of the elementary cells is chosen as a largest for a volume range that has a smallest gradient of the permittivity variation.

18. The method according to claim 16, wherein: the size of an elementary cell, in the statistical mean, averaged over the volume of the guide element is larger where the gradient of the permittivity is smaller; and the size of an elementary cell, in the statistical mean, averaged over the volume of the guide element is smaller where the gradient of the permittivity is larger.

19. The method according to claim 18, wherein the size of the elementary cells are chosen so that the maximum permittivity or the maximum spatial permittivity gradient is translated into a proportional spatial point density, and the points are used as development points for a three-dimensional Voronoi partitioning of the volume of the guide element.

20. The method according to claim 16, wherein the size of the elementary cell in the one volume range is dependent on the maximum gradient of the permittivity in the one volume range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a guide element according to the invention in the form of an elliptical lens in accordance with aspects of the invention,

(2) FIG. 2a is a first example of an elementary cell, in which the material is arranged in an irregular structure in accordance with aspects of the invention,

(3) FIG. 2b is a second example of an elementary cell, in which the material is arranged in an irregular structure in accordance with aspects of the invention,

(4) FIG. 2c is a first example of an elementary cell, in which the material is arranged in a regular structure in accordance with aspects of the invention,

(5) FIG. 2d is a second example of an elementary cell, in which the material is arranged in a regular structure in accordance with aspects of the invention,

(6) FIG. 2e is a third example of an elementary cell, in which the material is arranged in a regular structure in accordance with aspects of the invention,

(7) FIG. 3 is a cross section through a lens for demonstrating a steady permittivity course in sections of the lens in accordance with aspects of the invention,

(8) FIG. 4 is a flow chart of the method according to aspects of the invention,

(9) FIGS. 5a and 5b show an embodiment with varying elementary cell size in dependence on the gradient of the permittivity course in accordance with aspects of the invention, and

(10) FIGS. 6a and 6b show an embodiment with structure cells that, in the statistical mean, are greater in larger elementary cells than in smaller elementary cells in accordance with aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

(11) A guide element 1 according to the invention in the form of an elliptical lens 2 of an antenna is illustrated in FIG. 1. The lens 2 is impinged with electromagnetic radiation by a supply element 3, the radiation then being emitted via the lens surface 4. The lens 2 is produced of a dielectric material. There are areas 6, 7 located in the lens 2, in which the material density differs from the material density of the rest of the lens 2. The lens 2 has a spatial distribution of the material density over its spatial expansion. The permittivity of the dielectric material is dependent on the material density, so that the lens has a changing permittivity course over its spatial expansion. The material density is defined by one portion of material 5 per elementary cell 8 of a given size.

(12) The material can be arranged differently in the elementary cells. In FIG. 2a to FIG. 2e, cross sections through elementary cells, having a rectangular cross section, are illustrated. The cross section of the elementary cell does not have to be rectangular, moreover, the choice of the shape of the elementary cell is arbitrary.

(13) FIG. 2a shows a first example of an elementary cell 8, in which the material 5 is arranged in an irregular structure. The material 5 hereby has a closed porosity, i.e., has hollow spaces 9 that are not connected to one another. The hollow spaces 9 have different sizes and are randomly arranged in the material 5.

(14) FIG. 2b shows a further example of an elementary cell 8, in which the material 5 is arranged in an irregular structure. Here, worm-like hollow spaces 10 are implemented in the material 5. The hollow spaces 10 are also randomly arranged in the material 5, so that no higher organized structure is created by the hollow spaces 10.

(15) As a first example for an arrangement of the material 5 in a regular structure, the material 5 in FIG. 2c is arranged in the form of honeycombs 11. In a regular structure, it is taken into account that the structures are implemented in one size, which does not lead to an undesired structurally caused influence of the electromagnetic radiation.

(16) FIGS. 2d and 2c show the cross section of an elementary cell 8, in which the material 5 is arranged in the form of a sequence built of cubes 12 and thus has a regular structure. The material density can, for example, be influenced by the thickness d of the cube walls. In this manner, the chosen structure in the elementary cells is the same in FIGS. 2d and 2e, however, the elementary cells in FIG. 2e have a higher material density than the elementary cells in FIG. 2d.

(17) The illustrated structures can be implemented in a particularly suitable manner using a generative manufacturing method. The choice of the manufacturing method is hereby dependent on the choice of material and the chosen structure.

(18) A cross section 13 of a lens 2 is illustrated in FIG. 3. The illustration is schematic and is used for demonstrating the permittivity course P in the lens. For this, the lens is divided into squares over the cross section. The numbers in the squares stand for a permittivity value, wherein the number 10 represents the highest possible permittivity and the number 1 represents the lowest possible permittivity. In the middle, at the bottom, the lens 2 has an area of high as possible permittivity, the squares are marked with a 10. The permittivity decreases to the upper edge of the lens 2 in the figure. Hereby, the permittivity in this area chronicles a linear course from the lower middle up to the upper edge of the lens. This distribution of the permittivity is an example of a continuous, steady permittivity course in parts of the spatial expansion of the lens 2.

(19) Areas are also shown, which are characterized by steps in the permittivity. The permittivity in the right, lower area of the lens 2 shown in the figure decreases from a permittivity value of 10 directly to a permittivity value of 2. The course is only shown in an exemplary manner in a two-dimensional cross section. Seen over the entire lens, the permittivity course P can take on any arbitrary course.

(20) A few elementary cells 8 are further illustrated in FIG. 3. The elementary cells 8 are shown with bold outlines. It can be seen that the elementary cells 8 have different sizes. The size of the respective elementary cell 8 is hereby chosen in dependence on the gradient of the permittivity course P.

(21) The elementary cell 8.sub.1 is the largest illustrated elementary cell. Within the elementary cell 8.sub.1, the permittivity varies between 3 and 2, thus the gradient is very small, so that a large elementary cell can be chosen. The elementary cell 8.sub.2 has a smaller size. Within the elementary cell 8.sub.2, the permittivity varies between 6 and 4, so that the gradient within the elementary cell 8.sub.2 is also small. However, this elementary cell 8.sub.2 is surrounded on its upper side by areas of a permittivity of 10. Here, the larger gradient exists, so that the area of the permittivity of 10 is not included in the unit cell 8.sub.2. The elementary cell 8.sub.2 has a permittivity of 7 at the right edge of the lens 2. In the surroundings, however, the permittivity is much smaller with values of 1 and 2, so that a large gradient exists. The size of the elementary cell 8.sub.3 is accordingly chosen to be very small.

(22) FIGS. 5a and 6a show an identical permittivity course P in a guide element that is not illustrated in detail, the course being independent on only one location coordinate x. The permittivity () initially starts on a low plateau for small x-values, then increases steeply in a middle area and reaches a plateau for large x-values at a high permittivity value. The course belonging to the permittivity course P of the gradient G of the permittivity course P is also shown in a qualitative manner.

(23) The embodiment shown in FIGS. 5a, 5b, 6a, and 6b is used for explaining the formation principle for an implemented irregular structure S.sub.U within elementary cells 8 of different sizes.

(24) It can be seen in FIG. 5b, that the size of the elementary cells 8 in one volume range, of which only the two-dimensional extension over the x- and y-axes is shown, is dependent on the gradient G of the permittivity course P in the volume range. The gradient G is also sketched in FIGS. 5a and 6a for a better understanding of the principle, these are not mathematically exact curves.

(25) FIG. 5b shows that the size of the elementary cells 8 is chosen to be the smallest for the volume range that has the largest gradient G of the permittivity course P (average x-values) and that the size of the elementary cells 8 is chosen to the be the largest for the volume range that has the smallest gradient G of the permittivity course P (small and large x-values). In this manner, it is sensibly ensured that large local changes of the permittivity course are tapped, finely graduated, and implemented in the guide element.

(26) FIG. 6b shows the structural implementation of the spatial distribution of the material density corresponding to the permittivity course in that an irregular structure S.sub.U is implemented by a spatial Voronoi tessellation of the elementary cells 8. Here, the spatial distribution of the material density of the dielectric material 5 is implemented by varying the density of the structure cells 18, of which the Voronoi tessellation of the elementary cells 8 consist, while retaining the wall thickness of the structure cells. The coordinates of the centers of the Voronoi cells shown by points can be given by a numerical random process. In this manner, corresponding predetermined density distribution of stochastic point clouds can be generated.

(27) In the present case, the irregular structure S.sub.U is formed by adjacent structure cells 18, these being Voronoi cells. The size of the structure cells 18 changes in dependence on the size of the elementary cells 8, in which the respective structure cells 18 are located. The structure cells 18, in statistical mean, are larger in large elementary cells 8 than the structure cells 18 in small elementary cells 8.

(28) A flow chart of a method according to the invention is illustrated in FIG. 4, with which the guide element 1 according to the invention can be produced. In a first step 100, a permittivity distribution is provided in the spatial expansion of the guide element. The permittivity distribution is attuned to the use of the guide element here.

(29) In a further step 110, a corresponding material density distribution corresponding to the given permittivity course P is then specified. In order to be able to implement the material density distribution, a structure is specified that implements the material density distribution in a further step 120.

(30) For specifying the structure, the guide element 1 is previously divided into elementary cells.

(31) In the last step 130, the structure is then produced using a generative manufacturing method. It is preferred in specifying the structure to take into account that no higher-level structures are created that could unintentionally influence the electromagnetic radiation, since formation of the radiation is only to take place by varying the material density and, thus, varying the effective permittivity.