Antenna arrangement with resonance element

Abstract

The invention refers to a radome (1) for a base station antenna and a method for manufacturing the radome (1). The radome (1) comprises a multiwall-sheet (2), wherein the multiwall-sheet (2) comprises an outer wall (3) and an inner wall (4), the outer wall (3) being parallel to the inner wall (4), wherein the outer wall is connected to the inner wall (4) by multiple connecting walls (5), wherein the multiple connecting walls (5) are aligned to be parallel with respect to each other. Each one of the multiple connecting walls (5) is extending in a first direction (y) and a second direction (z) in a corresponding cross-sectional plane of the radome (1); wherein the multiwall sheet (2) is bent to have a first curved section (6); and wherein each one of the connecting walls (5) follows a curvature of the first curved section (6) in its corresponding cross-sectional plane of the radome (1).

Description

[0001] Antenna arrangement with resonance element

[0002] Technical field

[0003] The invention refers to the technical field of base station antennas and radomes for base station antennas.

[0004] Background

[0005] Most base station antennas according to the art comprise radomes that are manufactured from one stiff peace in fibreglass radome technology. To reduce costs, it is desirable that other materials are used. However, it has shown that some materials that might lead to cost improvements do not fulfil the requirements in respect to a required stiffness, which has lead to additional efforts in respect to supporting structures that have to be provide to keep the radome in shape in harsh weather conditions.

[0006] A radome for a base station antenna according to the invention comprises a multiwall-sheet. The multiwall-sheet comprises an outer wall and an inner wall, the outer wall being parallel to the inner wall, wherein the outer wall is connected to the inner wall by multiple connecting walls wherein the multiple connecting walls are aligned to be parallel with respect to each other. Each one of the multiple connecting walls is extending in a first direction and a second direction in a corresponding cross-sectional plane of the radome. The multiwall sheet is bent to have a first curved section, wherein each one of the connecting walls follows a curvature of the first curved section in its corresponding cross-sectional plane of the radome.

[0007] It is important for a radome of base station antennas that the beam characteristic of the corresponding base station antenna are not influenced in a negative way. Therefore, it is to be avoided that any surfaces that are covering the radiating components of the base station antenna comprise structures that might lead to a distortion of emitted radio beams. One might expect that bending the multiwall-sheet to have the first curved section would lead to a undesirable deformation, in particular to wrinkles, on the inner wall, the outer wall and / or the multiple connecting walls. However, practical tests have shown that no or at least only neglectable deformations occur when forming the curvature of the first curved section. At the same time, the curvature of the multiwall-sheet leads to an increased stability of a radome or radome segment that is formed from the multiwall-sheet.

[0008] 1

[0009] P112534Multiwall-sheets are commercially available for low costs and have shown to be resistant to environmental influences. However, the stiffness of the multiwall-sheets, which is lower than the stiffness of other materials that are typically used for radomes, made it necessary to provide support structures that were able to keep the multiwall-sheet in shape and position. According to the invention, the connecting walls of the multiwall-sheet are bent in a specific way that allows the connecting walls to form parallel bridges over an interior of the base station antenna. This leads to a high stability of the radome that allows the use of the multiwall-sheet as radome component, even without any supporting structure.

[0010] A method for manufacturing a radome according to the invention comprises providing a plateshaped multiwall-sheet, wherein the multiwall-sheet comprises an outer wall and an inner wall, the outer wall being parallel to the inner wall, wherein the outer wall is connected to the inner wall by multiple connecting walls, wherein the multiple connecting walls are aligned to be parallel with respect to each other, and applying heat to the plate-shaped multiwall-sheet and bending the multiwall-sheet for applying a curvature under the influence of the applied heat, wherein the multiwall sheet is curved after the bending such that each one of the multiple connecting walls is extending in a first direction and a second direction in a corresponding cross-sectional plane of the radome, wherein the multiwall sheet is bent to have a first curved section, wherein each one of the connecting walls follows a curvature of the first curved section in its corresponding cross-sectional plane of the radome. The method according to the invention is suitable to manufacture the radome according to the invention.

[0011] A base station according to the invention comprises a radome according to the invention.

[0012] The dependent claims define advantageous embodiments of the invention.

[0013] In particular, the multiwall-sheet is of a thermoplastic material and the curvature of the curved section is a thermoplastic deformation of the multiwall-sheet. Even though it might be expected that a thermoplastic deformation of the multiwall-sheet leads to wrinkles in surfaces of the multi-wall-sheet, which would have a negative impact on the damping characteristics of the radome, it has shown that potential wrinkles are only very small, not having any relevant negative impact on the damping characteristics of the radome.

[0014] In particular, the corresponding cross-sectional plane is perpendicular to the outer wall and / or the inner wall of the multiwall-sheet.

[0015] 2

[0016] P112534In particular, the multiwall sheet is bent to have a second curved section, wherein each one of the connecting walls follows a curvature of the second curved section in its corresponding cross-sectional plane of the radome.

[0017] In particular, the multiwall-sheet is forming a U-shaped radome segment.

[0018] In particular, the base station antenna comprises the radome, wherein the multiwall-sheet is mounted on a first side of the multiwall-sheet and a second side of the multiwall-sheet, wherein the first side and the second side of the multiwall-sheet are opposing ends of the multiwallsheet, wherein the outer wall and the inner wall are both connecting the first side to the second side, and wherein each one of the connecting walls is connecting the first side to the second side.

[0019] In particular, the base station antenna comprises the radome, wherein the curved multiwallsheet is unsupported in between the first side and the second side.

[0020] In particular, the base station antenna comprises the radome, wherein the multiwall-sheet is forming a U-shaped radome segment, wherein radiating elements of the base station antenna are aligned to be covered from at least two sides by the U-shaped radome segment.

[0021] P112534Brief description of the drawings

[0022] Fig. 1 shows an exemplary multiwall-sheet that can be used as a multiwall-sheet in a radome according to embodiments of the invention;

[0023] fig. 2 shows two different views of a radome according to embodiments of the invention;

[0024] fig. 3 shows a base station antenna according to embodiments of the invention;

[0025] fig. 4 shows a three-dimensional illustration of a radome according to embodiments of the invention; and

[0026] fig. 5 shows a flowchart of a method for manufacturing a radome according to embodiments of the invention.

[0027] Detailed description

[0028] Figure 1 shows an exemplary multiwall-sheet 2 that can be used as a multiwall-sheet 2 in a radome 1 according to embodiments of the invention.

[0029] The multiwall-sheet 2 comprises an outer wall 3 and an inner wall 4. In figure 1, the outer wall 3 is forming a top surface of the multiwall-sheet 2 and the inner wall 4 is forming a bottom surface of the multiwall-sheet 2. The outer wall 3 is extending parallel to the inner wall 4. The outer wall 3 and the inner wall 4 are plate shaped and are both flatly extending in a xz-plane. It is to be noted that the multiwall-sheet of figure 1 is to be bent along the z-direction for forming the radome 1 or a segment of the radome 1. After bending, the outer wall 3 and the inner wall 4 will no longer be flatly extending in the xz-plane.

[0030] The outer wall 3 is connected to the inner wall 5 by multiple connecting walls 5. Each one of the multiple connecting walls 5 is aligned to be parallel to the other connecting walls 5. Thus, the multiple connecting walls 5 are aligned to be parallel with respect to each other. Each one of the connecting walls 5 is aligned to perpendicular to the outer wall 3. Each one of the connecting walls 5 is aligned to perpendicular to the inner wall 4. Each one of the multiple connecting walls 5 is plate shaped is flatly extending in a yz-plane. It is to be noted that each connecting wall 5 of figure 1 will still extend flatly in the yz-plane after bending the multiwall-sheet 2 for forming the radome 1 or segment of the radome 1. After bending, the outer wall 3 and the inner wall 4 will follow a curvature along the z-direction.

[0031] 4

[0032] P112534The x-direction, y-direction and z-direction are perpendicular to each other. The yz-plane is extending in the y-direction and z-direction. The xz-plane is extending in the x-direction and z-di-rection. A xy-plane is extending in the x-direction and y-direction.

[0033] Figure 2 shows two different views of a radome 1 according to embodiments of the invention The radome 1 is formed from the multiwall-sheet 2 that is described in view of Figure 1. The radome has been bent to have a first curved section 6 and a second curved section 7. The first curved section 6 and a second curved section 7 lead to a U-shape of the radome 1.

[0034] The upper view of Figure 2 shows a top-view of the radome 1 in the xz-plane. The top surface of the multiwall-sheet 2 can be seen. The multiple connecting walls 5 are indicated, even though they are covered by the outer wall 3 in this view. This is to show the alignment of the multiple connecting walls 5 in respect to a curvature of the multiwall-sheet 2.

[0035] The lower view of Figure 2 shows a cross-sectional view of the radome 1 along a cross-sectional plane 10 in the yz-plane. The multiwall-sheet 2 is bent downwards in the y-direction on opposing ends to form the first curved section 6 and the second curved section 7. The outer wall 3 is no longer flatly extending in the xz-plane but is curved after bending. Also, the inner wall 4 is no longer flatly extending in the xz-plane but is curved after bending. Each one of the multiple connecting walls 5 is extending in the y-direction and the z-direction, that is in the yz-plane, in the corresponding cross-sectional plane of the radome 1.

[0036] The lower view of Figure 2 shows a cross-sectional plane of the radome 1 that corresponds to an exemplary connecting wall 5a. The exemplary connecting wall 5a is flatly extending in the y-direction and the z-direction, that is in the yz-plane, in its corresponding cross-sectional plane 10 of the radome 1. Same applies for each one of the multiple connecting walls 5. Therefore, the multiple connecting walls 5 are extending in a first direction, that is the y-direction, and a second direction, that is the z-direction, in a corresponding cross-sectional plane of the radome 1. As the multiple connecting walls 5 do extend in the yz-plane but the multiwall-sheet 2 is bent to have the first curved section 6 and the second curved section 7, each one of the connecting walls 5 follows a curvature of the first curved section 6 in its corresponding cross-sectional plane of the radome 1 and each one of the connecting walls 5 follows a curvature of the second curved section 7 in its corresponding cross-sectional plane of the radome 1.

[0037] The multiwall-sheet 2 is bent to have the first curved section 6 and the second curved section 7. In preferable embodiments, the multiwall-sheet 2 is of a thermoplastic material and the curvature of the curved section 6 is a thermoplastic deformation of the multiwall-sheet 2. In particular,

[0038] 5

[0039] P112534the multiwall-sheet 2 has been heated up to be in a temperature range that allows the thermoplastic deformation and a force has been applied to bend the multiwall-sheet 2 to have the first curved section 6 and the second curved section 7. Each one of the multiple connecting walls 5 maintains in the yz-plane before and after the thermoplastic deformation, that is before and after bending the multiwall-sheet 2 to have the first curved section 6 and the second curved section 7.

[0040] The first curved section 6 and the second curved section 7 give a U-shape to the multiwallsheet 2 that allows to arrange radiating elements of a base station antenna underneath the curved multiwall-sheet 2. The curvature leads to a very stable structure of the radome 1, which optionally allows to omit any further supporting structure for the radome 1.

[0041] Preferably, the multiwall-sheet 2 of the radome 1 is longer in x-direction than in z-direction.

[0042] As described, the curved multiwall-sheet 2 can be used as the radome 1. Optionally, the curved multiwall-sheet 2 can be a part of a radome. That is, the curved multiwall-sheet 2 can be a radome segment, in particular a U-shaped radome segment. Optionally, two curved multiwallsheets 2, each one of the curved multiwall-sheets 2 comprising one, two or more curved sections can be combined to form a radome.

[0043] Figure 3 shows a base station antenna 20 according to embodiments of the invention. In an example, the base station antenna 20 is an antenna of a macro-cell base station. The base station comprises the radome 1. Preferably, the radome 1 is aligned such that the x-direction is a vertical direction and that the z-direction is a horizontal direction.

[0044] The base station antenna 20 comprises a base plate 24. A reflector 23 is mounted on the base plate 24. Radiating elements 21 , 22 of the base station antenna 20 are mounted in front of the reflector 23, that is between the reflector 23 and the radome 1.

[0045] The multiwall-sheet 2 is mounted on a first side 8 of the multiwall-sheet 2 and a second side 9 of the multiwall-sheet 2. In this embodiment, the first side 8 of the multiwall-sheet 2 and the second side 9 of the multiwall-sheet 2 is mounted to the base plate 24. In other embodiments, the first side 8 of the multiwall-sheet 2 and the second side 9 of the multiwall-sheet 2 can be mounted to other entities of the base station antenna 20, in particular to further components of the radome 1. The first side 8 and the second side 9 of the multiwall-sheet 2 are opposing ends of the multiwall-sheet 2 in z-direction. the outer wall 3 and the inner wall 4 are both connecting the first side 8 to the second side 9. In addition, each one of the connecting walls 5 is connecting the first side 8 to the second side 9.

[0046] 6

[0047] P112534Due to the stiff structure that is achieved by bending the multiwall-sheet such that the multiple connecting walls 5 follow the curvature of the first curved section 6 and the second curved section 6, it is not necessary to provide supporting elements to support the radome 1. Therefore, the curved multiwall-sheet 2 is unsupported in between the first side 8 and the second side 9.

[0048] The multiwall-sheet 2 is forming the U-shaped radome segment, wherein the radiating elements 21, 22 of the base station antenna 20 are aligned to be covered from at least two sides, in this example from three sides, by the U-shaped radome segment.

[0049] Figure 4 shows a three-dimensional illustration of a radome 1 according to embodiments of the invention. The radome 1 comprises two multiwall-sheets 2a, 2b, which correspond to the multi-wall-sheet 2 of the preceding embodiments. Both of the multiwall-sheets 2a, 2b are U-shaped. Instead of being mounted of a base plate, the U-shaped multiwall-sheets 2a, 2b are mounted to each other to define a inner space that allows a protected placement of the components of the base station antenna 20. For this, the first side 8a of a first multiwall-sheet 2a is connected to the second side 9b of a second multiwall-sheet 2b. The second side 9a of the first multiwallsheet 2a is connected to the first side 8b of a second multiwall-sheet 2b.

[0050] Figure 5 shows a flowchart of a method 100 for manufacturing a radome according to embodiments of the invention. The method can be used in manufacturing the radome 1 according to any of the above-described embodiments.

[0051] A first step 101 comprises providing a plate-shaped multiwall-sheet 2, wherein the multiwallsheet 2 comprises an outer wall 3 and an inner wall 4, the outer wall 3 being parallel to the inner wall 4, wherein the outer wall 3 is connected to the inner wall 4 by multiple connecting walls 5, wherein the multiple connecting walls 5 are aligned to be parallel with respect to each other.

[0052] A second step 102 comprises applying heat to the plate-shaped multiwall-sheet 2 and bending the multiwall-sheet 2 for applying a curvature under the influence of the applied heat, wherein the multiwall-sheet 2 is curved after the bending such that each one of the multiple connecting walls 5 is extending in a first direction, for example the z-direction, and a second direction, for example the y-direction, in a corresponding cross-sectional plane of the radome 1. The multiwall sheet 2 is bent to have a first curved section 6 and preferably a second curved section 7, wherein each one of the connecting walls 5 follows a curvature of the first curved section 6 in its corresponding cross-sectional plane of the radome 1.

[0053] 7

[0054] P112534

Claims

Claims1. A radome (1) for a base station antenna, comprising a multiwall-sheet (2);wherein the multiwall-sheet (2) comprises an outer wall (3) and an inner wall (4), the outer wall (3) being parallel to the inner wall (4), wherein the outer wall is connected to the inner wall (4) by multiple connecting walls (5) wherein the multiple connecting walls (5) are aligned to be parallel with respect to each other;wherein each one of the multiple connecting walls (5) is extending in a first direction (y) and a second direction (z) in a corresponding cross-sectional plane of the radome (1); wherein the multiwall sheet (2) is bent to have a first curved section (6); andwherein each one of the connecting walls (5) follows a curvature of the first curved section (6) in its corresponding cross-sectional plane of the radome (1).

2. The radome (1) according to claim 1 , wherein the multiwall-sheet (2) is of a thermoplastic material and the curvature of the first curved section (6) is a thermoplastic deformation of the multiwall-sheet (2).

3. The radome (1) according to any one of claims 1 or 2, wherein the corresponding cross- sectional plane is perpendicular to the outer wall (3) and / or the inner wall (4) of the multi- wall-sheet (2).

4. The radome (1) according to any one of claims 1 to 3, wherein the multiwall sheet (2) is bent to have a second curved section (7), wherein each one of the connecting walls (5) follows a curvature of the second curved section (7) in its corresponding cross-sectional plane of the radome (1).

5. The radome (1) according to any one of claims 1 to 3, wherein the multiwall-sheet (2) is forming a U-shaped radome segment6. A base station antenna (20) comprising the radome (1) according to any one of claims 1 to 5.

7. The base station antenna (20) according to claim 6,8P112534wherein the multiwall-sheet (2) is mounted on a first side (8) of the multiwall-sheet (2) and a second side (9) of the multiwall-sheet (2), wherein the first side (8) and the second side (9) of the multiwall-sheet are opposing ends of the multiwall-sheet (2);wherein the outer wall (3) and the inner wall (4) are both connecting the first side (8) to the second side (9); andwherein each one of the connecting walls (5) is connecting the first side (8) to the second side (9).

8. The base station antenna (20) according to claim 7, wherein the curved multiwall-sheet (2) is unsupported in between the first side (8) and the second side (9).

9. The base station antenna (20) according to any one of claims 6 to 8, wherein the multi- wall-sheet (2) is forming a U-shaped radome segment, wherein radiating elements (10) of the base station antenna (20) are aligned to be covered from at least two sides by the U- shaped radome segment.

10. A method (100) for manufacturing a radome (1), the method comprising:providing (101) a plate-shaped multiwall-sheet (2), wherein the multiwall-sheet (2) comprises an outer wall (3) and an inner wall (4), the outer wall (3) being parallel to the inner wall (4), wherein the outer wall (3) is connected to the inner wall (4) by multiple connecting walls (5), wherein the multiple connecting walls (5) are aligned to be parallel with respect to each other; andapplying heat (102) to the plate-shaped multiwall-sheet (2) and bending the multiwall-sheet (2) for applying a curvature under the influence of the applied heat, wherein the multiwallsheet (2) is curved after the bending such that each one of the multiple connecting walls (5) is extending in a first direction (y) and a second direction (z) in a corresponding cross- sectional plane of the radome (1); wherein the multiwall sheet (2) is bent to have a first curved section (6); wherein each one of the connecting walls (5) follows a curvature of the first curved section (6) in its corresponding cross-sectional plane of the radome (1).P112534

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