The present application claims the benefit of priority to Chinese Patent Application 202010385103.X, filed on May 9, 2020, the disclosure of which is herein incorporated by reference in its entirety for all purposes.
The present invention generally relates to radio communications and, more particularly, to base station antennas for cellular communications systems.
Cellular communications systems are well known in the art. In a typical cellular communications system, a geographic area is divided into a series of regions that are referred to as “cells,” and each cell is served by a base station. The base station may include baseband equipment, radios and base station antennas that are configured to provide two-way radio frequency (“RF”) communications with subscribers that are positioned throughout the cell. In many cases, the cell may be divided into a plurality of “sectors,” and separate base station antennas provide coverage to each of the sectors. The antennas are often mounted on a tower, with the radiation beam (“antenna beam”) that is generated by each antenna directed outwardly to serve a respective sector. Typically, a base station antenna includes one or more phase-controlled arrays of radiating elements, with the radiating elements arranged in one or more vertical columns when the antenna is mounted for use. Herein, “vertical” refers to a direction that is perpendicular to the horizontal plane that is defined by the horizon. Reference will also be made to the azimuth plane, which is a horizontal plane that bisects the base station antenna, and to the elevation plane, which is a plane extending along the boresight pointing direction of the antenna that is perpendicular to the azimuth plane.
A common base station configuration is the “three sector” configuration in which a cell is divided into three 120° sectors in the azimuth plane. A base station antenna is provided for each sector. In a three sector configuration, the antenna beams generated by each base station antenna typically have a Half Power Beamwidth (“HPBW”) in the azimuth plane of about 65° so that each antenna beam provides good coverage throughout a 120° sector. Three such base station antennas provide full 360° coverage in the azimuth plane. Typically, each base station antenna will include one or more so-called “linear arrays” of radiating elements that includes a plurality of radiating elements that are arranged in a generally vertically-extending column. Each radiating element may have an azimuth HPBW of approximately 65° so that the antenna beam generated by the linear array will have a HPBW of about 65° in the azimuth plane. By providing a phase-controlled column of radiating elements extending along the elevation plane, the HPBW of the antenna beam in the elevation plane may be narrowed to be significantly less than 65°, with the amount of narrowing increasing with the length of the column in the vertical direction.
As the volume of cellular traffic has grown, cellular operators have added new cellular services in a variety of new frequency bands. When these new services are introduced, the existing “legacy” services typically must be maintained to support legacy mobile devices. In some cases, it may be possible to use linear arrays of so-called “wide-band” or “ultra-wide-band” radiating elements to support service in the new frequency bands. In other cases, however, it may be necessary to deploy additional linear arrays (or multi-column arrays) of radiating elements to support service in the new frequency bands. Due to local zoning ordinances and/or weight and wind loading constraints, there is often a limit as to the number of base station antennas that can be deployed at a given base station. Thus, to reduce the number of antennas, many operators deploy so-called “multiband” base station antennas that include multiple linear arrays of radiating elements that communicate in different frequency bands to support multiple different cellular services.
Additionally, or alternatively, dual-beam antennas (or multi-beam antennas) may be used to reduce the number of antennas on the tower. A key aspect of such multi-beam antennas is the use of a beamforming network (BFN). For example, the antenna 11 of
However, as discussed in U.S. Pat. No. 9,831,548, which is incorporated by reference, the main drawback of the prior art antenna of
In order to reduce large sidelobes that may result from using a base station antenna with increased electronic downtilt, the present disclosure provides base station antennas in which the columns of at least one of the modules are staggered or offset with respect to each other. In some embodiments, a majority of the modules that are present within the base station antenna may include such staggered column arrangements.
According to some aspects of the present disclosure, a multi-beam cellular antenna is provided. The multi-beam cellular antenna may include an antenna array having a plurality of modules, each module comprising at least three columns of radiating elements each having first polarization radiators, wherein the columns of radiating elements of at least one of the modules are staggered with respect to each other; and an antenna feed network configured to couple at least a first input signal and a second input signal to each first polarization radiator of each of the radiating elements included in a first of the plurality of modules.
In some embodiments, the radiating elements of the columns of radiating elements of a majority of the modules are staggered with respect to each other. In some embodiments, the radiating elements of the columns of radiating elements of at least one of the modules are aligned with respect to each other.
A first module of the plurality of modules may include three columns of radiating elements, and wherein a second module of the plurality of modules may include four columns of radiating elements. In some embodiments, the three columns of radiating elements of the first module may each include an equal number of radiating elements. In some embodiments, a first column of radiating elements of the first module may include a number of radiating elements that is less than a number of radiating elements included in a second column of the first module. The antenna feed network may include a 2×3 beamforming network that couples the first and second input signals to the radiating elements of the first module and a 2×4 beamforming network that couples the first and second input signals to the second module. The 2×4 beamforming network may include at least one variable power divider.
The antenna array may be configured to generate a first beam that points in a first direction responsive to the first input signal and to generate a second beam that points in a second direction responsive to the second input signal.
The radiating elements may be cross-polarized radiating elements.
According to some aspects of the present disclosure, a multi-beam cellular antenna is provided. The multi-beam cellular antenna may include a plurality of first modules each having a first number of columns of radiating elements. The radiating elements of the columns of at least one of the first modules may be staggered with respect to each other. The multi-beam cellular antenna may also include a plurality of second modules each having a second number of columns of radiating elements. The radiating elements of the columns of at least one of the second modules may be staggered with respect to each other. The multi-beam cellular antenna may also include an antenna feed network that includes at least one 2×4 beamforming network that couples first and second input signals to the radiating elements of one of the plurality of first modules, and at least one 2×3 beamforming network that couples the first and second input signals to the radiating elements of one of the plurality of second modules.
The radiating elements of the columns of radiating elements of a majority of the first modules may be staggered with respect to each other. The radiating elements of the columns of radiating elements of at least one of the second modules may be aligned with respect to each other. Each first module may include four columns of radiating elements, and each second module of the plurality of modules may include three columns of radiating elements. The 2×4 beamforming network may include at least one variable power divider.
The plurality of first modules and plurality of second modules may be configured to generate a first beam that points in a first direction responsive to the first input signal and may be configured to generate a second beam that points in a second direction responsive to the second input signal.
According to some aspects of the present disclosure, a multi-beam cellular antenna is provided. The multi-beam cellular antenna may include a plurality of first modules each having a first number of columns of radiating elements. The radiating elements of the columns of at least one of the first modules may be staggered with respect to each other. The multi-beam cellular antenna may also include a second module having a second number of columns of radiating elements. The radiating elements of the columns of the second module may be staggered with respect to each other. The multi-beam cellular antenna may also include an antenna feed network that includes at least one 2×4 beamforming network that couples first and second input signals to the radiating elements of one of the plurality of first modules, and at least one 2×3 beamforming network that couples the first and second input signals to the radiating elements of the second module.
A first column of radiating elements of the second module may include a number of radiating elements that is less than a number of radiating elements included in a second column of the second module.
The multi-beam cellular antenna may further include a third module having the second number of columns of radiating elements. The columns of the third module may be staggered with respect to each other. Each column of the third module may include an equal number of radiating elements as the first column of radiating elements of the second module.
As discussed in the above-referenced U.S. Pat. No. 9,831,548, a base station antenna that is currently of interest includes a plurality of modules of radiating elements.
As shown in
As seen in
Each three-column antenna module 80 of the base station antenna 300 of
Although the incorporated U.S. Pat. No. 9,831,548 discusses that the base station antenna 300 results in radiation patterns having low sidelobes in both the azimuth and elevation planes, the present disclosure results from the recognition that a large sidelobe may be present when there is a large degree of electronic downtilt applied to the antenna beams, e.g., from phase shifting. Increasing electronic downtilt is frequently desirable as it may be used to reduce the size of a cell when a new adjacent cell is added by a network operator. One way of increasing capacity is to use a larger number of smaller cells.
In order to reduce large sidelobes that may result from using a base station antenna with increased electronic downtilt, the present disclosure provides base station antennas in which the columns of at least one of the modules 80, 90 are staggered or offset with respect to each other. In some embodiments, a majority of the modules 80, 90 that are present within the base station antenna may include such staggered column arrangements.
The presence of staggered column arrangements may help to equalize RF energy on both sides of the main lobe. Although this may result in an increase in a lower sidelobe (e.g., the low sidelobe 1030), there is an overall positive result and improvement in performance of antennas with such arrangements resulting from the reduction in a higher sidelobe (e.g., the high sidelobe 1020).
As seen in
The base station antenna 400 of
In some embodiments, the base station antenna 400 may include one or more than one non-staggered three-column module 80. In some embodiments, the base station antenna 400 may include one or more than one non-staggered four-column module 90. As can be seen from comparing a length L1 parallel to the longitudinal axis L of the staggered three-column module 180 with a length L2 parallel to the same axis of the non-staggered or aligned three-column module 80, the length of a staggered module may be greater than a non-staggered module. In order to size the base station antenna 400 to satisfy, for example, local zoning ordinances and/or weight and wind loading constraints, a non-staggered module may be used on either or both ends of the base station antenna 400 to reduce the overall length thereof.
Each staggered three-column antenna module 180 of the base station antenna 400 of
Additionally, or alternatively, in some embodiments at least some of the radiating elements 76 described herein and the modules or base station antennas including such radiating elements 76 may be configured to provide a multi-input-multi-output (MIMO) array of “high-band” radiating elements that operate in, for example, some or all of the 1.7-2.7 GHz frequency band, the 3.4-3.8 GHz frequency band, or the 5.1-5.8 GHz frequency band. Massive MIMO arrays typically have at least four columns of radiating elements, and as many as thirty-two columns of radiating elements. In some embodiments, two or more base station antennas 400 of
While the discussion above focuses on radiating elements, it will be appreciated that the techniques discussed above can be used with radiating elements that operate in any appropriate frequency band.
Aspects of the present disclosure have been described above 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. Like numbers refer to like elements throughout.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (i.e., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.).
Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer or region to another element, layer or region as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
Aspects and elements of all of the embodiments disclosed above can be combined in any way and/or combination with aspects or elements of other embodiments to provide a plurality of additional embodiments.
Number | Date | Country | Kind |
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202010385103.X | May 2020 | CN | national |
Number | Name | Date | Kind |
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9831548 | Timofeev | Nov 2017 | B2 |
10181657 | Ai | Jan 2019 | B2 |
Number | Date | Country | |
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20210351505 A1 | Nov 2021 | US |