WO2013033894A1

WO2013033894A1 - Antenna assembly

Info

Publication number: WO2013033894A1
Application number: PCT/CN2011/079398
Authority: WO
Inventors: Stephen Haworth
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2011-09-07
Filing date: 2011-09-07
Publication date: 2013-03-14

Abstract

The present invention relates to an antenna assembly for wireless communication systems, comprising an antenna part and an antenna signal processing part together forming an integrated antenna assembly; said antenna part comprising at least one antenna element adapted for receiving/transmitting wireless communication signals, and said antenna signal processing part comprising at least one processing unit adapted for signal processing communication signals to and/or from said at least one antenna element; said antenna part and said antenna signal processing part being attached to each other in a common plane (P); wherein said antenna signal processing part has a first groove part (Gr1) and said antenna part has a complementary second groove part (Gr2) together forming at least one common groove (CGr) which extends between said antenna part and said antenna signal processing part and is adapted for receiving at least one sealing gasket (G) for sealing said antenna assembly, and wherein said common groove (CGr) has at least one wall section perpendicular to said common plane (P), and said sealing gasket (G) has at least one compressible sealing means acting on said wall section in a direction parallel to said common plane (P). Furthermore, the invention also relates to a sealing gasket (G).

Description

ANTENNA ASSEMBLY

Technical Field

The present invention relates to an antenna assembly for wireless communication systems, and more especially to an integrated antenna assembly. Furthermore, the invention also relates to a sealing gasket for sealing such an integrated antenna assembly.

Background of the Invention

Traditionally, an antenna is a passive component in a wireless communication system. Communication cables from the antenna feed radio frequency signals to a Remote Radio Unit (RRU) which is located a distance from the antenna. The further the RRU from the antenna the larger the loss in the signal reception and transmission due to e.g. resistance in the communication cables. Typical functionalities of a RRU is e.g. filtering and converting of analogue radio frequency signals to digital signals, baseband processing of incoming data, signal processing, and signal strength boosting of transmission signals, etc. Figure 1 schematically shows a traditional antenna system with a passive antenna unit connected to a RRU via a communication cable.

Therefore, to reduce mentioned signal loss and improve overall performance and power consumption so called active antenna systems has been proposed. An active antenna system integrates one or more of the functionalities of a RRU with the passive antenna and allows for other performance enhancements. In this respect, the RRU comprises active electronics, such as power amplifiers, signal processing devices, AD converters, high speed fibre optic devices and power supply. However, the inclusion of active electronics within the integrated antenna requires that the antenna housing has the same environmental protection classification required as for the RRU.

In prior art passive antenna designs, the housing simply encases the antenna array from the outdoor environment, since the antenna is a passive part of the network and does not house active electronics. Passive antennas require a level of outdoor environmental protection to prevent corrosion of elements and contacts, but it does not need to be fully sealed against water or dust ingress as there are no active electrical components in a passive antenna. However, active antennas having active electronics have to be sealed against water and dust ingress.

Furthermore, the introduction of active electronics into the antenna also require cooling of the electronics, which adds a further level of complexity to the antenna design, including the incorporation of a heat sink which is exposed to the air to allow for natural convection cooling of the active components of the antenna. The height of such antenna array is often over 1 meter in height and manufacturing tolerances of long heat sinks increase the risk that gaps will appear between the cover (radome) and the heat sink leading to water and dust ingress that cannot be solved by traditional antenna construction techniques. This additional level of complexity to the antenna design requires a higher level of environmental protection from dust and water ingress.

Summary of the Invention

The object of the present invention is to provide an antenna assembly which mitigates and/or solves the disadvantages of prior art solutions. The invention especially aims to solve the problem of sealing integrated active antennas.

According to an aspect of the invention, the objects are achieved with an antenna assembly for wireless communication systems, comprising an antenna part and an antenna signal processing part together forming an integrated antenna assembly;

- said antenna part comprising at least one antenna element adapted for receiving/transmitting wireless communication signals, and

- said antenna signal processing part comprising at least one processing unit adapted for signal processing communication signals to and/or from said at least one antenna element;

- said antenna part and said antenna signal processing part being attached to each other in a common plane; wherein

- said antenna signal processing part has a first groove part and said antenna part has a complementary second groove part together forming at least one common groove which extends between said antenna part and said antenna signal processing part and is adapted for receiving at least one sealing gasket for sealing said antenna assembly,

- and wherein said common groove has at least one wall section perpendicular to said common plane, and said sealing gasket has at least one compressible sealing means acting on said wall section in a direction parallel to said common plane. Different embodiments of the antenna assembly are disclosed in the appended dependent claims.

According to another aspect of the invention, the objects are also achieved with a sealing gasket for sealing an antenna assembly, said antenna assembly comprising an antenna part and an antenna signal processing part together forming an integrated antenna assembly, said antenna part comprising at least one antenna element adapted for receiving/transmitting wireless communication signals, and said antenna signal processing part comprising at least one processing unit adapted for signal processing communication signals to and/or from said at least one antenna element, said antenna part and said antenna signal processing part being attached to each other in a common plane; wherein said sealing gasket has at least one compressible sealing means acting on a wall section of a common groove of said antenna assembly in a direction parallel to said common plane.

Different embodiments of the sealing gasket are disclosed in the appended dependent claims.

The present invention provides a water tight seal which protects the internal electronics built into integrated antennas from being damaged by moisture or dust ingress into the antenna unit. The seal provides protection against moisture and dust ingress to sensitive electronics and allows for an embodiment with a heat sink to aid with the cooling of the aforementioned electronics. Furthermore, the use of gasket seals according to the invention allows for maintenance operations to be performed by being easier to separate the parts of the antenna for repair, upgrade and for recycling when the antenna reaches the end of its useable life.

Yet another advantage of the invention is that the present sealing solution reduces the number of fastening means, such as screw fittings, needed to maintain a satisfactory seal allowing for tolerance variations in the manufacturing process of other parts. This is due to the present sealing arrangement which also improves the attachment of the antenna part and the signal processing part. The reduced number of fasteners allows for reduced assembly time and production cost. Further applications and advantageous of the invention will be apparent from the following detailed description.

Brief Description of the Drawings

The appended drawings are intended to clarify and explain different embodiments of the present invention in which:

Figure 1 schematically shows a traditional antenna system with a passive antenna unit connected to a RRU;

Figure 2 schematically illustrates a common plane P in which the antenna part and the antenna signal processing are attached to each other to form an integrated antenna assembly;

Figure 3 schematically shows when the antenna part and the antenna signal processing part are separated, and when mentioned parts are assembled;

Figure 4 schematically shows a sealing gasket to be used in an antenna assembly according to the invention; and

Figure 5 schematically shows an antenna assembly according to the invention viewed from above.

Detailed Description of the Invention

As aforementioned, with the introduction of active antennas in wireless communication systems there is a need for proper environmental protection of such antennas.

Therefore, the present invention relates to an integrated antenna assembly comprising a passive antenna part and an active antenna signal processing part. The former part comprising at least one antenna element (but often an array of antenna elements for antenna beam control in cellular communication systems) for receiving/transmitting wireless communication signals, and the latter part comprising one or more signal processing units or any other active component for processing wireless communication signals. The two parts are in communication with each other by means of one or more communication interfaces, such as communication cables or other means. It should be understood that a processing unit in this disclosure should have a wide interpretation and may incorporate such as Digital Signal Processor (DSP), power amplifier, AD or DA converters, etc. The antenna part and the antenna signal processing part are attached to each other in a common plane P, and such common plane P is illustrated in figure 2. Further, the antenna signal processing part has a first groove part Grl and the antenna apart has a second groove part Gr2 which is complementary to the first groove part Grl. In this way a common groove CGr is formed by the two groove parts Grl, Gr2 which extends between the antenna signal processing part and antenna part parallel to the common plane P. The common groove CGr, which has at least one wall section perpendicular to the common plane P, is arranged to receive a sealing gasket G for sealing the antenna assembly. The sealing gasket G according to the invention comprises at least one compressible sealing means which acts on the wall section in a direction parallel to the common plane P. Thereby, a sealing is provided which protects the antenna assembly and its active components from water and dust ingress. At the same time, due to the compression of the compressible sealing on the wall section/sections in the direction parallel to the common plane P, a reduced number of fasteners is needed for the attachment of the antenna signal processing part and the antenna part thereby securing the antenna assembly as an integrated antenna.

Figure 3 shows a further embodiment of the invention, where the upper drawing shows when the antenna signal processing part and the antenna part are separated, while lower drawing shows when the two parts are assembled. The antenna signal processing part comprises a first groove part Grl. The complementary second groove part Gr2 is located on the antenna part and in this example in the (plastic) radome R. As seen in the figure 3, a sealing gasket G is placed in the second groove part Gr2.

When assembling the antenna a common groove CGr is formed of mentioned two groove parts Grl, Gr2, and the common groove CGr has in this embodiment two opposite positioned wall sections which are arranged perpendicular to the common plane P, therefore rendering the common groove CGr at least one part which is U-shaped. When the antenna is assembled, the sealing gasket G fits tight into the common groove CGr and the compressible sealing means act on the respective wall sections in two opposite directions illustrated with arrows in figure 3 according to this embodiment. It should be noted that the two opposite directions both are parallel to the common plane P so as to achieve suitable compression on the respective wall sections. Hence, the invention allows an antenna to be integrated with a radio processing unit (such as a RRU) and at the same time providing a water and dust proof seal which complies with the environmental protection standard qualification required for this type of antennas.

Regarding the compressible sealing means, these are according to an embodiment protrusions comprised in the sealing gasket G, and preferably the protrusions have the shape of vanes or ribs or any other suitable shapes with corresponding function. The compressible sealing means provide multiple points of contact improving the quality of the seal and reducing the possibility of liquid or dust entering the antenna assembly. The invention also relates to a sealing gasket G for sealing an integrated antenna assembly with active components. The present sealing gasket G has at least one compressible sealing means acting on a wall section of a common groove CGr of the antenna assembly in a direction parallel to the common plane P. The sealing gasket G is preferably made of a compressible material, such as silicon rubber or any other suitable material with the compression and sealing properties. Figure 4 shows a preferred embodiment of a sealing gasket G according to the invention, where the upper left drawing shows the sealing gasket G in cross section and the lower right drawing shows a perspective view of the sealing gasket G arranged to run in a common groove CGr extending along the circumference of the antenna assembly, which is illustrated in figure 5.

This particular sealing gasket G in figure 4 comprises, in use, a first part which is arranged perpendicular to the common plane P, the first part having one or more compressible sealing means such as vanes or ribs. Further, the sealing gasket G comprises, in use, at least one second part which is parallel to the common plane P. Thus, a substantially L-shaped sealing gasket is provided which fits into the common groove CGr. However a T-shaped sealing gasket G would also work well in a suitable common groove CGr. The second part secures the sealing gasket in the radome R. According to the embodiment in figure 4, the sealing gasket G may have at least one dimple located in the first parts of the sealing gasket G and being oriented perpendicular to the common plane P. The dimple is arranged to receive at least one protrusion of the antenna part and/or the antenna signal processing part so that the first part of the sealing gasket G is expanded in the common groove CGr in a radial direction relative to the axis of the dimple thereby increasing the force acting on the wall section/sections perpendicular to the common plane P for a tighter fit in the common groove CGr. It has been mentioned that with the integration of active circuits in an antenna assembly, proper cooling is need. An effective and reasonable priced solution is the use of heat sinks HS made of aluminum. The drawback is however that these heat sinks HS have to be of considerable size if the cooling should be effective. With the size there is a risk that gaps appear between the heat sink HS and the other part of the antenna assembly which destroys the sealing.

The embodiment in figure 3 comprises a heat sink HS (of which only a part is shown) made of aluminum having one or more cooling flanges (not shown). The heat sink HS also functions as a cover for the antenna signal processing part in this embodiment therefore covering the whole antenna signal processing part. The antenna assembly in figure 3 further comprises a (plastic) radome R protecting the antenna part. In this preferred embodiment, the first groove part Grl is located in the heat sink HS, while the second groove part Gr2 is located in the radome R. The antenna assembly is preferably used as base station antenna in cellular wireless communication systems and therefore adapted for radio frequencies in such systems. Examples of such systems are: GSM, UMTS, LTE, and LTE-Advanced. However, the present invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claim.

Claims

1. Antenna assembly for wireless communication systems, comprising an antenna part and an antenna signal processing part together forming an integrated antenna assembly; - said antenna part comprising at least one antenna element adapted for receiving/transmitting wireless communication signals, and

- said antenna part and said antenna signal processing part being attached to each other in a common plane (P); characterised in that

- said antenna signal processing part has a first groove part (Grl) and said antenna part has a complementary second groove part (Gr2) together forming at least one common groove (CGr) which extends between said antenna part and said antenna signal processing part and is adapted for receiving at least one sealing gasket (G) for sealing said antenna assembly, - wherein said common groove (CGr) has at least one wall section perpendicular to said common plane (P), and said sealing gasket (G) has at least one compressible sealing means acting on said wall section in a direction parallel to said common plane (P).

2. Antenna assembly according to claim 1, wherein said common groove (CGr) has at least two opposite located wall sections perpendicular to said common plane (P).

3. Antenna assembly according to claim 2, wherein said common groove (CGr) has at least one U-shaped part comprising said two opposite located wall sections.

4. Antenna assembly according to claim 2, wherein said sealing gasket (G) has a plurality of compressible sealing means acting on said two opposite located wall sections.

5. Antenna assembly according to claim 1, wherein said compressible sealing means comprises protrusions on said sealing gasket (G).

6. Antenna assembly according to claim 5, wherein said protrusions have the shape of vanes or ribs.

7. Antenna assembly according to claim 1, wherein said antenna signal processing part further comprises at least one heat sink (HS).

8. Antenna assembly according to claim 7, wherein said heat sink (HS) further function as a cover for said antenna signal processing part.

9. Antenna assembly according to claim 7, wherein said heat sink (HS) has one or more cooling flanges and/or is made of metal, such as aluminium.

10. Antenna assembly according to claim 7, wherein said antenna processing part and said antenna part cover a surface area of substantially equal size.

11. Antenna assembly according to claim 10, wherein said heat sink (HS) covers the whole of said antenna signal processing part.

12. Antenna assembly according to claim 7, wherein said first groove part (Grl) is at least partly located in said heat sink (HS).

13. Antenna assembly according to claim 1, wherein said antenna part further comprises a radome (R) covering said antenna part, and said second groove part (Gr2) is at least partly located in said radome (R).

14. Antenna assembly according to claim 1, wherein said common groove (CGr) extends along the circumference of said antenna assembly.

15. Antenna assembly according to claim 1, wherein said sealing gasket (G) is made of a compressible sealing material, such as silicon rubber.

16. Antenna assembly according to claim 15, wherein said sealing gasket (G) has a shape equal to a part of the shape of said common groove (CGr).

17. Antenna assembly according to claim 1, wherein said antenna part and said antenna signal processing part are attached to each other by means of one or more fastening means, such as screws, bolts, rivets and adhesives.

18. Antenna assembly according to claim 1, wherein said common plane (P) is perpendicular to a main radiation direction of said antenna assembly.

19. Antenna assembly according to claim 1, wherein said antenna assembly is adapted for cellular wireless communication systems, such as GSM, UMTS, LTE and LTE advanced.

20. Antenna assembly according to claim 1, wherein said antenna assembly is a base station antenna.

21. Sealing gasket for sealing an antenna assembly, said antenna assembly comprising an antenna part and an antenna signal processing part together forming an integrated antenna assembly, said antenna part comprising at least one antenna element adapted for receiving/transmitting wireless communication signals, and said antenna signal processing part comprising at least one processing unit adapted for signal processing communication signals to and/or from said at least one antenna element, said antenna part and said antenna signal processing part being attached to each other in a common plane (P); characterised in that said sealing gasket (G) has at least one compressible sealing means adapted to act on a wall section of a common groove (CGr) of said antenna assembly in a direction parallel to said common plane (P).

22. Sealing gasket according to claim 21, wherein said compressible sealing means comprises protrusions on said sealing gasket (G).

23. Sealing gasket according to claim 22, wherein said protrusions have the shape of vanes or ribs.

24. Sealing gasket according to claim 21, wherein - said sealing gasket (G), in use, has at least one first part perpendicular to said common plane (P) and at least one second part parallel to said common plane (P), and

- said compressible sealing means is located on said first part.

25. Sealing gasket according to claim 24, wherein said first part comprises at least one dimple oriented perpendicular to said common plane (P), said dimple being adapted to receive at least one protrusion on said antenna part and/or said antenna signal processing part so as to expand said sealing gasket (G) in an outward direction.

26. Sealing gasket according to claim 24, wherein said sealing gasket is

substantially L-shaped or T-shaped in cross section.