Base station antenna system with adjustable reflector in a cylindrical radome

Abstract

The base station antenna sector comprises a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon, a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon, and a radome surrounding the first and second reflectors, the second reflector being pivotally movable relative to the first reflector.

Description

[Technical Field]

[0001] Related Applications This application claims priority to and the benefit of Chinese Patent Application No. 202211408858.2, filed on November 11, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to wireless communications, and more particularly to base station antenna systems that support communications in multiple frequency bands. [Background technology]

[0003] Cellular communication systems are well known in the art. In a cellular communication system, a geographic region is served by multiple cellular sites, which may be further divided into smaller cells called sectors.

[0004] Each sector may include one or more base station antennas (BSAs) configured to provide multiple-input multiple-output (MIMO) radio frequency communications with mobile subscribers in the cells served by the sector.

[0005] Each BSA typically includes one or more vertically extending columns of cross-polarized radiating elements (which may be straight columns or may include several horizontal staggers), referred to as a "linear array." A typical linear array is capable of two MIMO layers (streams), one for each of two orthogonal polarizations. A four MIMO layer configuration typically requires two horizontally spaced arrays, which significantly increases the overall antenna width (compared to antennas 10', 10'' in FIG. 1). Typically, the array of radiating elements is mounted on a reflector and housed within a protective radome.

[0006] Many BSAs are mounted on towers or other elevated structures and therefore face limitations in meeting structural wind load capabilities. This often leads to upgrading to four MIMO streams with wider antennas. Some markets, such as Japan, prefer a cylindrical radome shape because they may experience lower wind loads. However, in many cases, when the antenna(s) are housed within a cylindrical radome, a large amount of capacity within the radome often remains unused.

[0007] One approach is to build a base station antenna with two reflectors positioned so that their signal directions are separated by 120 degrees. In Figure 2, two reflectors 120, 120' in antenna 110 together provide four MIMO layers in a common direction of a single sector, with each reflector 120, 120' contributing to two MIMO layers. This design provides a slight width increase from the single-array antenna baseline case, significantly reducing wind load. However, a fixed 120-degree angular separation is impractical to deploy in many scenarios where the azimuth angle difference between sectors is non-uniform. Summary of the Invention

[0008] In a first aspect, an embodiment of the present invention is directed to a base station antenna sector comprising: a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon; a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon; and a radome surrounding the first and second reflectors, wherein the second reflector is pivotally movable relative to the first reflector.

[0009] In a second aspect, an embodiment of the present invention is directed to a base station antenna sector comprising: a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon; a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon; and a radome surrounding the first and second reflectors, wherein the first reflector is fixed relative to the radome and the second reflector is pivotally movable relative to the first reflector.

[0010] In a third aspect, an embodiment of the present invention is directed to a base station antenna sector comprising: a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon, a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon, the second reflector being pivotally movable relative to the first reflector about a pivot axis located between the first and second reflectors. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional top view illustrating the width increase of a base station antenna between an antenna with two MIMO layers and an antenna with four MIMO layers. [Figure 2] Figure 2 is a cross-sectional top view of an existing BSA design in which two reflectors are arranged in a single cylindrical radome at a 60 degree angle, resulting in the antenna diameter being minimized, and the reflectors have a fixed, uniform relative azimuth angle between 120 degree sectors. [Figure 3] 3A-3C are schematic cross-sectional views of a foldable base station antenna system illustrating the ability to achieve different relative reflector angles, according to embodiments of the present invention. [Figure 4] FIG. 4 is a perspective view of a base station antenna in accordance with an additional embodiment of the present invention. [Figure 5] FIG. 5 is a bottom view of the base station antenna of FIG. [Figure 6] FIG. 6 is a partial top perspective view of the base station antenna of FIG. 4 with the radome removed. [Figure 7] FIG. 7 is a top view of the base station antenna of FIG. 4 showing the reflector positioned to produce a 180 degree radiation angle. [Figure 8] FIG. 8 is a top view of the base station antenna of FIG. 4 showing the reflector positioned to produce a 120 degree radiation angle. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0013] Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity.

[0014] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present invention. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of this specification and the related art, and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein. Known functions or structures may not be described in detail for the sake of brevity and / or clarity.

[0015] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. As used herein, the terms "comprises" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components, but are further understood to not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y." As used herein, phrases such as "about X to Y" mean "about X to about Y."

[0016] It will also be understood that when an element is referred to as being "adjacent," "coupled," "connected," or "coupled" to another element, the element may be directly adjacent, directly coupled, connected, coupled, or in contact with the other element, or that intervening elements may be present. In contrast, when an element is referred to as being "directly adjacent," "directly coupled," "directly connected," "directly coupled," or "in direct contact" with another element, for example, there are no intervening elements present. Those skilled in the art will also understand that references to structures or features that are located "adjacent" another feature may have portions that overlap with or underlie the adjacent feature.

[0017] Spatially relative terms, such as "below," "lower," "bottom," "upper," "upper," "top," "bottom," and the like, may be used herein to facilitate the description of one element or feature in relation to another element(s) or feature(s) as shown in the figures. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if a device in the figures is turned over, an element described as "below" or "below" another element or feature would then be oriented "above" that other element or feature. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and therefore the spatially relative descriptors used herein may be interpreted accordingly.

[0018] It will also be understood that, as used herein, terms such as "example," "exemplary," and derivatives thereof are intended to refer to non-limiting example and / or variant embodiments discussed herein, and are not intended to indicate a preference for one or more embodiments discussed herein over one or more other embodiments.

[0019] Most mobile network operators around the world are experiencing exponentially increasing data traffic demands from their subscribers in terms of higher throughput and lower latency. This is driven in part by the evolution of users' smartphone capabilities. In 4G LTE, most smartphones supported two MIMO layers; however, in 5G, the majority of devices are capable of four MIMO layers.

[0020] As 5G traffic and 5G-enabled devices grow, operators are restructuring their spectrum assets from 4G to 5G. However, they face increasing challenges in upgrading to quad-layer MIMO due to antenna width. One challenge is the increased wind load, especially in the sub-1 GHz bands, which current urban structures may not be able to support. As mentioned above, some markets, such as Japan, prefer a cylindrical radome shape that offers reduced wind load resistance, but a concomitant problem is that a large amount of the volume of a cylindrical radome may remain unused.

[0021] Each BSA often contains one or more linear arrays. A typical linear array can transmit and receive two MIMO layers (streams), one in each of two orthogonal polarizations. Typically, a four MIMO layer configuration uses two horizontally spaced arrays, which increases the overall antenna width by a factor of about 1.6 (compare antennas 10 and 10' in Figure 1). Smaller horizontal separation can result in isolation degradation that impacts the performance of the linear array.

[0022] An efficient approach to minimizing the diameter and utilizing the radome's internal volume involves constructing a base station antenna with two reflectors with an angular separation between them, with each reflector pointing in a different direction. As shown in Figure 2, antenna 110 and antenna 110' jointly construct four MIMO streams in a common direction for sector A, with each antenna contributing two MIMO streams. Similarly, the other two sectors, B and C, are jointly constructed by antennas 110' and 110'', and antennas 110 and 110'', respectively. This design results in an antenna width increase of only about 1.15 from the single-array antenna baseline case (i.e., antenna 10 in Figure 1), significantly reducing wind loads. Isolation is also easily maintained between linear arrays.

[0023] To meet radio planning requirements, it is desirable to be able to adjust the relative angle between the two reflectors, allowing the solution to be deployed in azimuth angles with non-uniform sectors.

[0024] According to an embodiment of the present invention, a base station antenna system is provided that overcomes the above-mentioned size and fixed relative angle limitations for a cost-effective four-layer MIMO upgrade. As shown schematically in Figures 3A-3C, antenna 210 includes two reflectors 220, 220' mounted within a common cylindrical radome 230. Each reflector 220, 220' has one or more linear arrays of radiating elements (not shown) to increase the number of MIMO layers in small width increments.

[0025] As shown in Figures 3A-3C, reflectors 220, 220' are mounted within antenna 210 and are pivotable relative to one another. More specifically, in Figures 3A-3C, reflectors 220, 220' are connected via hinges 222 located on their side edges 224, 224', which define pivot axis A2. This arrangement allows reflectors 220, 220' to be adjusted so that, upon deployment, the angular separation of the sectors can be 120 degrees (Figure 3A - showing a 60 degree angle between reflectors 220, 220' themselves), 180 degrees (Figure 3C - showing a 0 degree angle between reflectors 220, 220'), or an angle between 120 and 180 degrees (e.g., 140 degrees - see Figure 3B - showing a 40 degree angle between reflectors 220, 220'). As shown, this arrangement can be deployed within a cylindrical radome 230 that has a smaller diameter compared to the four MIMO sectors shown in FIG. 1, which in turn can avoid unused volume within the radome 230.

[0026] It will be appreciated that the angle between reflectors 220, 220′ (and therefore the sector angle produced by reflectors 220, 220′) may be adjusted in a number of ways. In some embodiments, reflectors 220, 220′ may be adjusted manually. In other embodiments, reflectors 220, 220′ may be coupled to a mechanism (not shown) that drives reflectors 220, 220′ to their desired positions. In further embodiments, such a mechanism may be configured to be remotely activated so that adjustments may occur after antenna 210 is installed; remote activation can save time and effort by eliminating the need for a technician to scale a tower or the like to access antenna 210 for adjustments. Remote relative angle adjustment also allows sector azimuth angles to be adjusted periodically according to the day of the week or time of day as an optimization.

[0027] 4-8, therein is shown another embodiment of a base station antenna, generally designated 310. Similar to antenna 210, antenna 310 includes two reflectors 320, 320' mounted within a common cylindrical radome 330. Each reflector 320, 320' has one or more linear arrays 340 to increase the number of MIMO layers at edge-width increments. However, rather than being hinged at their side edges to allow relative pivotal movement, the pivot axis A3 of reflectors 320, 320' is located between reflectors 320, 320' at or near the center of antenna 310.

[0028] Referring to FIG. 6, it can be seen that reflector 320 is fixedly attached to a mounting framework 332 within antenna 310 via a bracket 334 extending from the rear side of reflector 320. Reflector 320' also has a bracket 334' extending from its rear surface; however, reflector 320' is not fixed to framework 332. Instead, bracket 334' is pivotally attached to bracket 334 of reflector 320 via a bolt and nut 336 that defines the aforementioned pivot axis A3 (FIG. 7). (The lower end of antenna 310 is shown in FIG. 6; it will be understood that a similar arrangement of pivotally interconnected brackets exists at the upper end of antenna 310.) In this manner, reflector 320' is free to pivot relative to reflector 320 about axis A3 to generate the desired sector angle.

[0029] 5 and 6, lower end cap 331 includes an arcuate slot 333. A post, pin, or the like (shown at 337 in FIG. 7) extends downward from reflector 320′ and is received in slot 333. Slot 333 helps guide reflector 320′ as it pivots and also acts as a “stop” to limit the angular movement of reflector 320′ (e.g., if slot 333 extends through an arc of approximately 60 degrees, reflector 320′ can pivot relative to reflector 320 through a similar angle).

[0030] 7 and 8 show reflectors 320, 320′ producing a 180-degree radiation angle (similar to FIGS. 7-3C) and a 120-degree radiation angle (similar to FIGS. 8-3A). It will be appreciated that any radiation angle between 120 degrees and 180 degrees is also achievable with antenna 310. Of course, greater or lesser radiation angle limitations may be produced with other configurations. Furthermore, those skilled in the art will appreciate that other pivot limiting structures may also be used, such as a pin or post extending upward from end cap 331, a stop member on one or both of brackets 334, 334′, or a bayonet-style pin and sleeve replacing nut and bolt 336 as the defining member of pivot axis A3.

[0031] Those skilled in the art will appreciate that in some embodiments, it may be desirable for both reflectors 320, 320′ to pivot relative to the framework 332. Such an arrangement may provide a user with additional options when adjusting the azimuth angle of the antenna 320, especially if the antenna 310 is already mounted on an antenna tower, monopole, or other structure.

[0032] Those skilled in the art will appreciate that the pivoting characteristics of the reflectors 220, 220', 320, 320' may be applicable to both single and multi-band arrays, and / or to low, mid, and high frequency bands.

[0033] Also, in some embodiments, the above antennas 210, 310 may be provided in combination with similar pivotable base station antennas or conventional antennas, in which case the overall base station antenna system may be formed into two or more sectors operating four MIMO layers per sector.

[0034] The foregoing is illustrative of the present invention and should not be construed as limiting thereof. While exemplary embodiments of the present invention have been described, those skilled in the art will readily appreciate that many modifications can be made in the exemplary embodiments without substantially departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present invention as defined in the claims. The present invention is defined by the following claims, including equivalents of the claims therein.

Claims

1. 1. A base station antenna sector comprising: a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon; a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon; a radome surrounding the first and second reflectors; A base station antenna sector, wherein the second reflector is pivotally movable relative to the first reflector.

2. 2. The base station antenna sector of claim 1, wherein the radome is generally cylindrical.

3. 3. A base station antenna sector according to claim 1 or 2, wherein the first reflector is fixedly mounted to a mounting framework within the radome.

4. 4. A base station antenna sector according to claim 1, wherein the second reflector pivots relative to the first reflector via hinges attached to adjacent side edges of the first and second reflectors.

5. 5. A base station antenna sector according to claim 1, wherein the second reflector pivots relative to the first reflector about a pivot axis located between the first and second flat panels.

6. 6. The base station antenna sector of claim 5, wherein the pivot axis is located adjacent a center of the radome.

7. A base station antenna sector according to any preceding claim, further comprising a pivot limiting structure for limiting the pivot arc of the second reflector.

8. A base station antenna sector according to any preceding claim, wherein the first and second reflectors are together configured to support a four-layer MIMO arrangement.

9. 1. A base station antenna sector comprising: a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon; a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon; a radome surrounding the first and second reflectors; A base station antenna sector, wherein the first reflector is fixed relative to the radome and the second reflector is pivotally movable relative to the first reflector.

10. 10. The base station antenna sector of claim 9, wherein the radome is generally cylindrical.

11. 11. A base station antenna sector according to claim 9 or claim 10, wherein the second reflector pivots relative to the first reflector via hinges attached to adjacent side edges of the first and second reflectors.

12. 12. A base station antenna sector according to any one of claims 9 to 11, wherein the second reflector pivots relative to the first reflector about a pivot axis located between the first and second flat panels.

13. 13. The base station antenna sector of claim 12, wherein the pivot axis is located adjacent a center of the radome.

14. A base station antenna sector according to any one of claims 9 to 13, further comprising a pivot limiting structure for limiting the pivot arc of the second reflector.

15. A base station antenna sector according to any one of claims 9 to 14, wherein the first and second reflectors are together configured to support a four-layer MIMO arrangement.

16. 1. A base station antenna sector comprising: a first reflector comprising a first flat panel and a plurality of first radiating elements mounted thereon; a second reflector comprising a second flat panel and a plurality of second radiating elements mounted thereon; a substantially cylindrical radome surrounding the first and second reflectors; A base station antenna sector, wherein the second reflector is pivotally movable relative to the first reflector about a pivot axis, the pivot axis being located between the first and second reflectors.

17. 17. The base station antenna sector of claim 16, wherein each of the first and second radiating elements is a MIMO radiating element.

18. 20. The base station antenna sector of claim 17, wherein the first and second reflectors together provide a four or more tier MIMO arrangement at different frequency ranges.

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