ANTENNA COVER, USE OF AN ANTENNA COVER, ADAPTER FOR CONNECTING TWO ANTENNA COVERS AND METHOD FOR PRODUCING A LENS-SHAPED ANTENNA COVER

Abstract

An antenna cover is provided, including a first base body and at least two first fins arranged on the first base body, the first base body having a curved surface, the two first fins being arranged symmetrically to a longitudinal axis of symmetry of the antenna cover and extending substantially parallel to the longitudinal axis of symmetry, the at least two first fins having a width that tapers as a distance from the first base body increases, and the at least two first fins being arranged with a spacing that corresponds substantially to the width of the at least two fins. A method for producing a lens-shaped antenna cover is also provided.

Claims

1.-15. (canceled)

16. An antenna cover, comprising: a first base body having a curved surface; and at least two first fins arranged on the first base body, the at least two first fins being arranged symmetrically to a longitudinal axis of symmetry of the antenna cover and extending substantially parallel to the longitudinal axis of symmetry, the at least two first fins having a width that tapers as a distance from the first base body increases, the at least two first fins being arranged with a spacing that substantially corresponds to the width of the at least two first fins, each of the at least two first fins having a crown region that follows a virtual mirrored curved surface of the first base body and that is less than a thickness of the first base body, and the virtual mirrored curved surface of the first base body and the curved surface of the first base body having a mirror axis and/or a mirror plane, which runs perpendicular to the longitudinal axis of symmetry.

17. The antenna cover according to claim 16, wherein the curved surface has an aspherical curvature.

18. The antenna cover according to claim 16, further comprising an even number of the at least two first fins.

19. The antenna cover according to claim 16, wherein the longitudinal axis of symmetry lies in a plane of symmetry, and wherein the first base body and the at least two first fins are arranged in minor symmetry to the plane of symmetry.

20. The antenna cover according to claim 16, wherein the at least two first fins are arranged in a comb-like manner along another width of the first base body.

21. The antenna cover according to claim 16, wherein the spacing between the at least two first fins has a valley region, and wherein the valley region lies on a parallel surface to the curved surface of the first base body.

22. The antenna cover according to claim 16, further comprising: a second antenna cover, having a second base body and a plurality of second fins, a number of the plurality of second fins differs by a value of 1 from a number of the at least two first fins, the plurality of second fins having a width that substantially corresponds to the spacing between the at least two first fins and that tapers as a distance from the second base body increases, the plurality of second fins being arranged with the spacing that substantially corresponds to the width between the at least two first fins, and the plurality of second fins engages according to the number of the plurality of second fins in each case in the spacing.

23. The antenna cover according to claim 16, wherein the at least two first fins are arranged as concentric circles and/or as parallel fins.

24. The antenna cover according to claim 21, wherein the width of the at least two first fins substantially corresponds to the thickness of the first base body in an area of the valley region of the spacing.

25. The antenna cover according to claim 16, wherein the cover is in a shape of a lens.

26. An antenna for a measuring device, the antenna comprising an antenna cover, the antenna cover comprising: a first base body having a curved surface; and at least two first fins arranged on the first base body, the at least two first fins being arranged symmetrically to a longitudinal axis of symmetry of the antenna cover and extending substantially parallel to the longitudinal axis of symmetry, the at least two first fins having a width that tapers as a distance from the first base body increases, the at least two first fins being arranged with a spacing that substantially corresponds to the width of the at least two fins, each of the at least two first fins having a crown region that follows a virtual mirrored curved surface of the first base body and that is less than a thickness of the first base body, and the virtual mirrored curved surface of the first base body and the curved surface of the first base body having a mirror axis and/or a mirror plane, which runs perpendicular to the longitudinal axis of symmetry.

27. A method for producing a lens-shaped antenna cover, comprising: providing a first antenna cover, comprising a first base body having a curved surface; and at least two first fins arranged on the first base body, the at least two first fins being arranged symmetrically to a longitudinal axis of symmetry of the first antenna cover and extending substantially parallel to the longitudinal axis of symmetry, the at least two first fins having a width that tapers as a distance from the first base body increases, the at least two first fins being arranged with a spacing that substantially corresponds to the width of the at least two first fins, each of the at least two first fins having a crown region that follows a virtual mirrored curved surface of the first base body and that is less than a thickness of the first base body, the virtual mirrored curved surface of the first base body and the curved surface of the first base body having a mirror axis and/or a mirror plane, which runs perpendicular to the longitudinal axis of symmetry, and the first antenna cover having an even number of fins; providing a second antenna cover, comprising a second base body having the curved surface; and at least two second fins arranged on the second base body, the at least two second fins being arranged symmetrically to the longitudinal axis of symmetry of the second antenna cover and extending substantially parallel to the longitudinal axis of symmetry, the at least two second fins having a width that tapers as a distance from the second base body increases, the at least two second fins being arranged with a spacing that substantially corresponds to the width of the at least two second fins, each of the at least two second fins having a crown region that follows a virtual mirrored curved surface of the second base body and that is less than a thickness of the second base body, the virtual mirrored curved surface of the second base body and the curved surface of the second base body having a mirror axis and/or a mirror plane, which runs perpendicular to the longitudinal axis of symmetry, and the second antenna cover having an odd number of fins; and joining the first antenna cover and the second antenna cover so that the at least two first fins of the first antenna cover are disposed in spacings of the second antenna cover, and the at least two second fins of the second antenna cover are disposed in spacings of the second antenna cover.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Further exemplary embodiments of the present invention are described in the following with reference to the drawings.

[0048] FIG. 1 is a cross section through an antenna cover according to an exemplary embodiment of the present invention.

[0049] FIG. 2 is a cross section of a lens in a separated state according to an exemplary embodiment of the present invention.

[0050] FIG. 3 is a cross section of an assembled lens according to an exemplary embodiment of the present invention.

[0051] FIG. 4 is a cross section of an alternative lens according to an exemplary embodiment of the present invention.

[0052] FIG. 5 is a cross section of a lens that is prepared for the use of a horizontal seal according to an exemplary embodiment of the present invention.

[0053] FIG. 6 is a cross section of a lens installed in a horn antenna of a fill level measuring device according to an exemplary embodiment of the present invention.

[0054] FIG. 7 is a cross section of an adapter and two antenna covers according to an exemplary embodiment of the present invention.

[0055] FIG. 8 is a cross section of a further adapter according to an exemplary embodiment of the present invention.

[0056] FIG. 9 is a flow chart for a method for the production of a cover from two antenna cover halves according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0057] The drawings are schematic and are not to scale. In the following description of FIGS. 1 to 9, the same reference numerals are used for identical or corresponding elements.

[0058] FIG. 1 is a cross section through an antenna cover according to an exemplary embodiment of the present invention. The antenna cover 100 has a first base body 101 and an even number of at least two first fins 102a, 102b. The even number of at least two fins forms the joining contour 103, joining means 103 or the attachment means 103. The base body 101 has the curved surface 104, which in an assembled state is one of the refraction surfaces of the finished lens. The refraction surface 104 can ensure a deflection of radiation 110 which passes through the antenna cover 100. The base body 101 and fins 102a, 102b are formed in one piece or are monolithic, as they are produced by injection moulding and form a common body of the antenna cover 100.

[0059] In the example of FIG. 1, the curved surface 104 is formed convex and can have a single radius of curvature or a plurality of radii of curvature. In the case of a plurality of radii of curvature, it is an aspherically curved surface 104, which can have differently curved regions. The curved surface 104 can have convex and/or concave regions. The antenna cover 100 is formed symmetrically with reference to a longitudinal axis of symmetry 105. In the case of concentrically arranged fins, the antenna cover can be rotationally symmetrical with reference to the axis of symmetry. In the case of fins running in parallel, the antenna cover 100 is formed in mirror symmetry with reference to a mirror plane, in which the axis of symmetry 105 lies, and which projects from the drawing plane. The lens may extend accordingly into the drawing plane or out of the drawing plane.

[0060] In FIG. 1, an antenna cover having only a single radius of curvature is shown. The curvature of the curved surface 104 has a radius of curvature +r1. The centre point M1 of the radius of curvature +r1 lies on the longitudinal axis of symmetry 105. In the case of an optical lens, the longitudinal axis of symmetry 105 can also be described as the optical axis 105.

[0061] The at least two fins 102a, 102b are arranged symmetrically to the longitudinal axis of symmetry 105 and substantially have a width d or thickness d. In this case the width d designates the width in a valley region 106b, 106a, 106 of the slots 107, 107b, 107a, gaps 107, 107b, 107a or spacings 107, 107b, 107a. The slots 107, 107b, 107a have substantially a width a, wherein the width a corresponds substantially to the thickness d of the fins. The shape of the fins 102a, 102b is formed so that these fins substantially fit into the slots 107, 107a, 107b without air inclusions. The fins 102a, 102b thus form a comb-like joining contour. Compared with the longitudinal axis of symmetry 105 or compared with a parallel to the longitudinal axis of symmetry 105, the fins have a draft angle ε, which can be 0.5° for example, or can lie in the range between 0.5° and 10°. In one example, a smallest possible thickness D of the base body 101 may be selected in order to facilitate good cooling of the base body 101 in an injection process. A small thickness D of the base body 101 can be realised, as the volume of the full body lens to be created is provided by the fins, which enter into the spacings a, 107, 107a, 107b. The spacing a may be selected to be smaller than D. Likewise the width d of a fin may be selected to be smaller than D. On account of the draft angle ε, the width d of a fin in the valley region 106, 106a, 106b is wider than in a crown region 109a, 109b. The width d of the fins thus decreases as the distance from the curved surface 104 or from the base body 101 increases. The spacing a of two adjacent fins accordingly increases as the distance from the base body 101 or from the curved surface 104 increases.

[0062] The curved surface 104 has a normal vector n.sub.1, n.sub.2, which with a vector s.sub.1, s.sub.2, which is oriented in the direction of extension of the fins 102a, 102b, encloses an angle 130a, 130b.

[0063] The angle 130a, 130b between the normal vector n1, n2 and fin vector s1, s2 lies in the range ]−90°, +90°[. In FIG. 1, the angle 130b may be +178°, for example, while the angle 130a is −177°.

[0064] In the valley region 106, 106a, 106b, the spacings 107, 107a, 107b or the gaps 107, 107a, 107b reach closest to the surface of the curved surface 104 and thus specify the thickness D of the base body 101. In other words, the distance of the valley regions 106, 106a, 106b from the surface of the curved surface 104 is at its smallest.

[0065] The fins 102a, 102b have the crown regions 109a, 109b, which at least in part have the greatest distance in each case of a constituent of the integrally formed antenna cover from the curved surface 104.

[0066] Starting out from the centre point Ml, which likewise represents the centre point of the radius +r1 of the curved surface 104, the valley regions 106, 106a, 106b lie on the radius +r1′. The length or the amount of the radius +r1′ is smaller than the amount of the radius +r1. The difference between the radius +r1′, on which the valley regions 106, 106a, 106b of the spacings 107, 107a, 107b lie, and the radius +r1 of the curved surface 104 amounts substantially to the wall thickness of the base body D.

[0067] Starting out from the direction of propagation of electromagnetic radiation, which is shown by the arrow 110 in FIG. 1 and runs parallel to the longitudinal axis 105 and to a longitudinal axis of the fins 102a, 102b, the radiation first strikes the curved surface 104 and then the assumed centre point M1 of the radius of curvature. The curved surface 104 is therefore a convex surface and the radii +r1, +r1′ are assumed as positive values.

[0068] With a corresponding counterpart or a corresponding further antenna cover, a lens can be constructed by means of the antenna cover 100. A lens has two curved surfaces. However, since the antenna cover forms only a part of the lens, the progression of the curved surface of the further antenna cover is assumed as virtual line 111 or virtual curved surface 111. The curved surfaces 104 and 111 are arranged symmetrically to the axis of symmetry 112. With reference to the axis of symmetry 112, the mirror axis 112 or the mirror plane 112, which runs perpendicular to the axis of symmetry 105, a centre point M2 can be constructed, starting out from which a radius of curvature −r2 shapes the curve of the virtual curved second side 111 of the lens formed by the antenna cover 100. M1 and M2 are arranged in a mirror image to the axis of symmetry 112. In the case of an aspherically curved surface 104, the axis of symmetry 112 is the axis of symmetry of the aspherical curves. With regard to this virtual mirrored and curved surface 111, the crown regions 109a, 109b of the fins 102a, 102b run following this surface 111, less the wall thickness D of the further antenna cover, which corresponds to the wall thickness D of the base body of the antenna cover. The wall thickness of a second antenna cover (not shown in FIG. 1) is assumed as equal to the wall thickness D of the antenna cover 100. The curve of the crown regions 109a, 109b of the fins 102a, 102b is described by the radius −r2′, which has the same centre point M2 as the radius of curvature −r2. In the case of fins arranged in a circle, the fins 102a, 102b designated by index a and b belong respectively to the same fin 102a, 102b. In the case of fins with a linear progression, the fins 102a, 102b are different fins.

[0069] The valley regions 106, 106a, 106b can be understood as support points of an “enveloping surface” or “envelope curve”. The enveloping surface of the valley regions 106, 106a, 106 runs parallel to the curved surface 104 with a spacing of substantially D. With regard to the axis of symmetry 112 or plane of symmetry 112, the crown regions 109a, 109b run symmetrically on an enveloping surface that runs parallel to the virtual lens surface 111. The envelope curve or enveloping surface of the crown regions or apexes 109a, 109b runs symmetrically to the envelope curve of the valley regions 106, 106a, 106b. The envelope curve of the valley regions 106, 106a, 106b is described by the radius +r1′, while the envelope curve of the crown regions 109a, 109b is described by the radius −r2′. The same applies to an aspherically shaped curved surface 104, 111. In other words, the crown regions 109a, 109b form support points, which have a similar progression to the curved surface 104. In another example, the valley regions 106, 106a, 106b or the crown regions 109a, 109b can lie on circular radii −r1′, −r2′, while the curved surfaces 104, 111 are formed aspherically.

[0070] Going beyond the width B, the antenna cover 100 has the attachment means 113a, 113b, which are implemented as attachment flanges 113a, 113b or antenna fastenings 113a, 113b. The attachment regions 113a, 113b can be used to fit sealing rings or O-rings as well as for attachment of the antenna cover 100 to a horn antenna (not shown in FIG. 1) or to any other horn. The attachment means 113a, 113b can also be used to align the parts of the lens when assembling the lens. For example, a cup-shaped wall on the attachment means 213a, 213b can be used to serve as a guide for the attachment means 113a, 113b.

[0071] FIG. 2 is a cross section of a lens in the separated state according to an exemplary embodiment of the present invention. FIG. 2 shows the antenna cover 100 and the further antenna cover 200. The further antenna cover 200 has a second base body 201 as well as a joining means 202 or joining contour 202, which has an odd number of second fins 203, 203a, 203b. In contrast to the spacing 107 present in the antenna cover 100 with respect to the longitudinal axis of symmetry 105, the further antenna cover 200 has the corresponding fin 203 or central fin 203. The fin 203 can engage with the spacing 107 or the gap 107 when the lens parts 100, 200 are joined together. A full lens can thus be formed, the curved surfaces 104, 204 of which are formed by the curved surface 104 of the first base body 101 and by the curved surface 204, which is provided by the second base body 201 of the further antenna cover 200. The attachment means 113a, 113b can engage with corresponding attachment means 213a, 213b of the second base body 201 and be used for alignment of the lens parts with one another. Free spaces in which condensate could collect are closed as far as possible.

[0072] FIG. 3 is a cross section of the assembled lens 300 or full lens 300 according to an exemplary embodiment of the present invention. The lens 300 has been formed by joining an antenna cover 100′ to the base body 101′ and the further antenna cover 200′ to the base body 201′. The curved surfaces 104′, 204′ form the refraction surfaces of the lens 300. In FIG. 3, the antenna cover 100′ used has no additional attachment regions 113a, 113b. Thus the width B of the antenna cover 100′ is formed by the width of the fins and the spacings or gaps between the fins. The outermost fins 102a′, 102b′ are used for alignment and attachment. The outermost fins 102b′, 102a′ come to rest in the attachment means 213b′ and 213a′ of the further antenna cover 200′.

[0073] The further antenna cover 200′ has openings 301a′, 301b′ in the attachment means 213a′, 213b′, which openings can be used to connect a fan for cleaning the lens 300. By joining the fins 102a′, 102b′ to the fins 203′, 203a′, 203b′, a lens 300 is formed as a solid body. The joining interface 302, which runs substantially sinusoidally and is formed by the surfaces of the fins, may be substantially free of air inclusions following assembly, so that the lens has substantially the same properties as a lens produced in one piece. The joining interface 302 is formed from the surface of the attachment means 103, 202. To produce the lens in one piece, fins 102a, 102b, 201 of two corresponding lens halves are used as filling material. In FIG. 3, it can also be seen that the crown regions of the respective fins 102a′, 102b′, 203′, 203a′, 203b′ substantially follow the contour of the surfaces 104′, 204′. In one example, the crown regions follow spherical radii. The radii lie in the range of the wall thickness. The crown regions are designated 109a′, 109b′ and the valley regions are designated 106′, 106a′, 106b′. The crown regions of the fins correspond to the progression of the respective curved surface in each spatial region or in each spatial direction, that is to say both in the drawing plane and into the drawing plane or out of it. A good fit can thus be ensured when forming the full lens in all spatial directions.

[0074] FIG. 4 is a cross section of a further assembled lens according to an exemplary embodiment of the present invention. The lens 400 is formed in this case from the antenna cover 100″ and 200″. In contrast to the crown regions of the fins 203′, 203a′, 203b′ and the valley regions 106a′, 106b′ of the fins 203′, 203a′, 203b′, which are shown in FIG. 3 as rounded crown regions and valley regions, the fins 102a″, 102b″, 203″, 203b″, 203a″ substantially have surfaces that run parallel to the surfaces 104″, 204″ and thus follow the surfaces 104″, 204″. They follow the surfaces in all spatial regions or spatial directions to ensure as few air inclusions as possible. In one region, the crown regions 109a″, 109b″ and valley regions 106″, 106a″, 106b″ follow the radii +r1′, −r1′. The entire surface curve 109a″, 109b″ and the surface curve 106″, 106a″, 106b″consequently follow the radii +r1′, −r2′ and not only one crown region or one valley region. The same applies to the other lens half 200″. The fins 102a″, 102b″, 203′, 203a′, 203b′ taper as the spacing from the respective base body of the antenna covers 100″, 200″ increases.

[0075] FIG. 5 shows a lens 500′″, which is prepared for use by means of a horizontal seal, according to an exemplary embodiment of the present invention. Serving as basis for the construction of the lens 500′″ are the lens parts 100, 200, which are to be inferred from FIG. 2 as the antenna cover 100 and the further antenna cover 200. In the case of the lens 500′″, due to the interaction of the attachment means 113a′″, 113b′″, 213a′″, 213b′″ recesses 501, 502 are present, on which a horizontal O-Ring or a horizontal sealing ring can be fitted for sealing purposes if the lens 500′″ is installed in a horn antenna. The recesses 501, 502 are a single recess or groove, which is formed as a circumferential ring around the entire lens-shaped antenna cover 500′″. The recess is formed between the two antenna covers.

[0076] FIG. 6 is a cross section of a lens 600 installed in a horn antenna or lens antenna of a fill level measuring device according to an exemplary embodiment of the present invention. The lens 600 is a lens formed by assembly of the antenna cover 100 and the further antenna cover 200 from FIG. 2. The attachment devices 113a, 213a and 113b, 213b interact in such a way that recesses 601a, 601b and 602a and 602b are created, into which sealing rings can be inserted. The recesses 601a, 601b and 602a and 602b can also be circumferential.

[0077] The antenna 603 has the horn-shaped antenna opening 604 or the widened antenna region 604, which expands in the direction of the lens 600. The assembled lens 600 is fastened in the attachment means 605a, 605b of the antenna opening 604 with the aid of the attachment means 113a, 213a, 113b, 213b provided on the lens 600, so that the cavity 606 is protected from penetrating particles. The attachment means 605a, 605b of the antenna opening 604 is formed as a circumferential flange. The attachment means 113a, 213a, 113b, 213b of the lens is formed rectangular or square, in order to be able to attach the lens surface securely in the antenna opening 604. The arrow 110 indicates the direction of an electromagnetic wave propagating in the direction of a filling material, which wave has been generated by a high-frequency device (not shown in FIG. 6) and which is used to measure the distance of a fill level. The electromagnetic wave first strikes the surface 104 of the antenna cover, then passes the solid body of the lens 600 formed from the fins 102a, 102b of the antenna cover 100 and the fins 203, 203a, 203b of the further antenna cover 200. The electromagnetic wave exits the lens body via the curved surface of the further antenna cover 200. In FIG. 6, the progression of the joint 302′ can likewise be seen. The width of the opening 607 of the waveguide 603 substantially corresponds to the width B of the antenna cover 100, 200. The attachment devices 113a, 213a and 113b, 213b can be used to match the width of the lens 600 to the antenna exit opening 607 or aperture 607.

[0078] FIG. 7 is a cross section of an adapter 700 and two further antenna covers 200, 200″″ according to an exemplary embodiment of the present invention. The adapter 700 has a plurality of fins 102a″″, 102b″″, 102c″″, 102d″″, which are arranged on the base body 104″″. In one approach, the adapter 700 is two symmetrically joined antenna covers 100, so that the curve of the crown regions and of the valley regions of the adapter 700 substantially corresponds to the curves described in FIG. 1. The same applies to the dimensioning. The adapter 700 can be used to form a lens in assembled form by means of a further antenna cover 200, 200″″. The combination of the fins 102a″″, 102b″″, 102c″″, 102d″″ and 203″″, 203a″″, 203b″″ and 203c″″, 203d″″ and 203e″″ and the base body 104″″ form the solid body of the lens 700. To create good conditions for the injection process, the adapter is also formed with a wall thickness that is as constant as possible. Due to the uniform construction, a homogeneous body can be formed. The cuneiform progression of the base body of the adapter is possible if the granulate is injected from the side in the injection moulding process.

[0079] FIG. 8 is a cross section of a further adapter according to an exemplary embodiment of the present invention. In the adapter 800, the valley regions 106′″″, 106a′″″, 106b′″″, 106c′″″, 106d′″″, 106e′″″ do not run along a curved surface, but substantially on a plane. The crown regions of the fins, however, run likewise on curved envelope curves, which correspond to the curved surfaces of the lenses.

[0080] When producing a cover using an injection moulding process, an injection mould is provided at the beginning, which makes possible the production of the antenna cover device 100 and/or of an adapter 800, 700. An injection mould is a negative mould of the antenna cover and/or of the respective adapter. The granulate from which the antenna cover 100 and/or the adapter 700, 800 is to be produced is also provided. The granulate is melted and injected into the injection mould, whereby the antenna cover and/or the adapter is formed. Following cooling, the antenna cover and/or the adapter can be removed from the injection mould.

[0081] FIG. 9 is a flow chart for a production method for a full lens from lens halves. When producing the full lens from the lens parts 100, 200, a first antenna cover 100 with an even number of fins is provided in a step S900. In step S901, a second antenna cover 200 with an odd number of fins is provided. In step S902, the joining of the two antenna covers takes place in that the comb-shaped attachment means 103, 202 are applied to one another in such a way that the central fin 203 of the antenna half 200 with an odd number of fins enters into the spacing 107 of the antenna half 100 with an even number of fins. For a better hold and to avoid air inclusions, an adhesive can be used between the joining structures 103, 202.

[0082] In addition, it should be pointed out that “comprising” and “having” do not exclude any other elements or steps and “a” does not exclude a plurality. Furthermore, it should be pointed out that features or steps that have been described with reference to one of the above embodiments can also be used in combination with other features or steps of other embodiments described above. Reference numerals in the claims are not to be regarded as a limitation.