REFERENCE TO PRIORITY APPLICATION [0001] This application claims priority to India Patent Application No. 202041013407, filed March 27, 2020, entitled “SHARED-APERTURE BASE STATION ANTENNAS WITH TRI-BEAM AND TWIN-BEAM GENERATION," the disclosure of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to radio communication systems and, more particularly, to multi-beam base station antennas (BSAs) utilized in cellular and other communication systems.

BACKGROUND

[0003] 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 or other raised structure, and the radiation beam ("antenna beam") generated by each antenna is generally 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 relative to the plane defined by the horizon. [0004] A common base station configuration is a "three sector" configuration in which a cell is divided into three 120° sectors in the azimuth plane, and the corresponding base station includes three base station antennas that provide coverage to the three respective sectors. The azimuth plane refers to a horizontal plane that bisects the base station antenna and that is parallel to the plane defined by the horizon. In a three sector configuration, the antenna beams generated by each base station antenna typically have a Half Power Beam Width ("HPBW") in the azimuth plane of about 65° so that the antenna beams provide good coverage throughout a 120° sector. Typically, each base station antenna will include at least one vertically-extending column of radiating elements that is typically referred to as a "linear array." Each radiating element in the linear array may have a HPBW of approximately 65° so that the antenna beam generated by the linear array can provide adequate coverage to a 120° sector in the azimuth plane. In many cases, the base station antenna may be configured as a "multi- band" antenna, which includes different arrays of radiating elements that operate in different frequency bands.

[0005] Sector-splitting refers to a technique whereby the coverage area for a base station is divided into more than three sectors in the azimuth plane, such as six, nine or even twelve sectors. A six-sector base station will have six 60° sectors in the azimuth plane. Splitting each 120° sector into two (or more) sub-sectors increases system capacity because each antenna beam provides coverage to a smaller area, and therefore can provide higher antenna gain and/or allow for frequency reuse within a 120° sector. In six-sector sector-splitting applications, a single twin beam antenna is typically used for each 120° sector. The twin beam antenna generates separate antenna beams having a reduced size in the azimuth plane (typically about half the size of a normal sector antenna beam) with each beam pointing in different directions in the azimuth plane (typically about -30° and 30° from the boresight pointing direction of the antenna) for at least one frequency band, thereby splitting the sector into two smaller sub-sectors.

[0006] Several approaches have been used to implement twin beam antennas. These antennas generate first and second antenna beams that provide coverage to respective first and second sub-sectors of a 120° sector in the azimuth plane. In a first approach, first and second linear arrays of radiating elements are mounted within an antenna. The linear arrays are mechanically positioned or “steered” to have different azimuth pointing angles, typically by bending the reflector of the antenna on which the linear arrays are mounted. The first linear array is mechanically steered so that the peak radiation therefrom will be at the middle of the first sub-sector, and the second linear array is mechanically steered so that the peak radiation therefrom will be at the middle of the second and adjacent sub-sector. Since the azimuth beamwidth of typical radiating elements may be appropriate for covering a full 120° sector, an RF lens may be mounted in front of the two linear arrays of radiating elements to thereby narrow the azimuth beamwidth of each antenna beam by a suitable amount for providing service to a 60° sub-sector. Unfortunately, the use of RF lenses may increase the size, weight and cost of the base station antenna. Moreover, the typical amount to which the RF lens narrows the beamwidth is a function of frequency, which makes it difficult to obtain suitable coverage when wideband radiating elements are required to operate over a relatively wide frequency range (e.g., radiating elements that operate over a full 1.7-2.7 GHz cellular frequency range).

[0007] In a second approach, two or more linear arrays of radiating elements (typically 2-4 linear arrays) are mounted within an antenna, and each linear array points toward the boresight pointing direction for the antenna. Two RF ports (per polarization) are coupled to the two or more linear arrays through a beamforming network such as a Butler Matrix. The beamforming network generates two separate antenna beams (per polarization) based on the RF signals input at the two RF ports, and the antenna beams are electrically steered off boresight at angles of about -30° and 30° to provide coverage to the two 60° sub-sectors. In beamforming networks based on twin beam antennas, the pointing angle in the azimuth plane of each antenna beam and the HPBW of each antenna beam may vary as a function of the frequency of the RF signals input at the two RF ports. In particular, the azimuth pointing direction of the antenna beams (i.e., the azimuth angle where peak gain occurs) tends to move toward the boresight pointing direction of the antenna and the azimuth HPBW tends to get narrower with increasing frequency, as shown in FIG. 1. This can lead to a large frequency-dependent variation in the power level of the antenna beam at the outside edges of the sub-sectors, which is often undesirable.

[0008] In a third approach, several linear arrays of radiating elements are mounted on corresponding panels of a V-shaped reflector, to thereby provide a sector-splitting twin beam antenna. A schematic transverse cross-sectional view of a conventional antenna 1 using this technique is provided in FIG. 2. As shown, the antenna 1 includes six linear arrays (20-1 through 20-6) of radiating elements 22 (with only one radiating element of each array being visible in the cross-sectional view of FIG. 2), which are mounted to extend forwardly of an underlying V-shaped reflector 10. While the antenna beams generated by the antenna 1 of FIG. 2 may vary less as a function of frequency in comparison to the lensed-based and beamforming-based twin beam antennas discussed hereinabove, the inclusion of six columns of radiating elements 22 may significantly increase the required width and/or depth for the antenna 1 , which may be undesirable, and the V-shaped reflector 10 may not provide suitable mounting locations and/or room for one or more lower-band linear arrays of radiating elements that are often required by network operators.

[0009] Cellular operators often desire twin beam antennas having azimuth HPBW values for each antenna beam in a range from 30° to 38°, so long as the azimuth HPBW does not vary significantly (e.g., more than 12°) across the operating frequency band of the linear arrays that generate the twin beams. Likewise, the azimuth pointing angle of the antenna beam peak may vary anywhere between +/- 26° to +/-33°, so long as the azimuth pointing angle does not vary significantly (e.g., more than 4°) across the operating frequency band of the linear arrays that generate the twin beams. The crossover point of the two antenna beams at the boresight pointing direction of the antenna (0°) may be about 9-12 dB below the peak gain. The azimuth roll off at the outer edges of the two 60° sub-sectors can be about 10-15 dB below the peak gain. The peak azimuth sidelobe levels should be at least 15 dB below the peak gain value.

SUMMARY

[0010] A base station antenna according to an embodiment of the invention can include a reflector including at least three generally forward facing reflector panels: a central reflector panel, a first side reflector panel extending rearwardly at a first acute angle relative to a front facing surface of the central reflector panel, and a second side reflector panel extending rearwardly at a second acute angle relative to the front facing surface of the central reflector panel. A multi-beam generator is provided, which is electrically coupled to an array of radiating elements on the first side, central and second side reflector panels. This multi-beam generator is configured as: (i) a tri-beam generator with respect to RF signals in a first frequency band, and further configured as: (ii) a dual-beam generator with respect to first RF signals in a second frequency band, and/or (iii) a multi-column beamformer with respect to second RF signals in the second frequency band. In some embodiments, the first frequency band may span a higher range of frequencies relative to the second frequency band.

[0011] According to further embodiments of the invention, the tri-beam generator is configured to: (i) drive radiating elements on the first side and central reflector panels with RF signals that support a first beam in the first frequency band, (ii) drive radiating elements on the second side and central reflector panels with RF signals that support a second beam in the first frequency band, and (iii) drive radiating elements on the central reflector panel with RF signals that support a third beam in the first frequency band. These first, second and third beams may be aligned with distinct first, second and central azimuth boresight pointing directions of the antenna, respectively. In addition, at least a first column of radiating elements on the central reflector panel may receive RF signals that support generation of portions of the first and third beams, and at least a second column of radiating elements on the central reflector panel may receive RF signals that support generation of portions of the second and third beams. This first column of radiating elements may extend along a first side of the central reflector panel and the second column of radiating elements may extend along a second side of the central reflector panel. Moreover, the tri-beam generator may include a first plurality of power dividers electrically coupled to the first column of radiating elements, and a second plurality of power dividers electrically coupled to the second column of radiating elements. The dual-beam generator may also include a Butler Matrix.

[0012] According to further embodiments of the invention, a base station antenna is provided, which includes a reflector having a plurality of rows and columns of radiating elements thereon. A multi-beam generator is provided, which is electrically coupled to the plurality of rows and columns of radiating elements. This multi-beam generator is configured as: (i) a tri-beam generator with respect to RF signals in a first frequency band, and further configured as: (ii) a dual-beam generator with respect to first RF signals in a second frequency band, and/or (iii) a multi-column beamformer with respect to second RF signals in the second frequency band.

[0013] According to another embodiment of the invention, a base station antenna is provided with a reflector having a central reflector panel, a first side reflector panel extending rearwardly at a first acute angle relative to a front facing surface of the central reflector panel, and a second side reflector panel extending rearwardly at a second acute angle relative to the front facing surface of the central reflector panel. A central array of radiating elements is provided, which is arranged as a plurality of rows and columns of radiating elements on the central reflector panel. A first side array of radiating elements is provided, which is arranged as a first plurality of rows and columns of radiating elements on the first side reflector panel. A second side array of radiating elements is provided, which is arranged as a second plurality of rows and columns of radiating elements on the second side reflector panel. A multi-beam generator is provided, which is electrically coupled to the radiating elements in the first side array, the central array and the second side array. The multi-beam generator is configured to:

(i) drive the first plurality of rows and columns of radiating elements and a first column of radiating elements in the central array with first RF signals in a first frequency band that support generation of a first beam which has a first azimuth boresight pointing direction;

(ii) drive the second plurality of rows and columns of radiating elements and a second column of radiating elements in the central array with second RF signals in the first frequency band that support generation of a second beam, which has a second azimuth boresight pointing direction that is different from the first azimuth boresight pointing direction; and (iii) drive the radiating elements in the central array with third RF signals in the first frequency band that support generation of a third beam, which is generally aligned with a third azimuth boresight pointing direction that is different than both the first and second azimuth boresight pointing directions. In some of these embodiments of the invention, the third azimuth boresight pointing direction may be within ± 5° of orthogonal to the front facing surface of the central reflector panel, and the first azimuth boresight pointing direction may be offset from the central azimuth boresight pointing direction by an amount greater than or equal to the first acute angle. Likewise, the second azimuth boresight pointing direction may be offset from the central azimuth boresight pointing direction by an amount greater than or equal to the second acute angle.

[0014] According to some further embodiments of the invention, each of the radiating elements in the first column of radiating elements in the central array may be located in a respective row that is offset from at least one row in the first side array of radiating elements containing a nearest neighbor radiating element. Similarly, each of the radiating elements in the second column of radiating elements in the central array may be located in a respective row that is offset from at least one row in the second side array of radiating elements containing a nearest neighbor radiating element.

[0015] In further embodiments of the invention, a base station antenna is provided with a reflector having at least three generally forward facing reflector panels, including a central reflector panel, a first side reflector panel extending rearward ly at a first acute angle relative to a front facing surface of the central reflector panel, and a second side reflector panel extending rearwardly at a second acute angle relative to the front facing surface of the central reflector panel. A central array of radiating elements is provided as a plurality of rows and columns of radiating elements on the central reflector panel.

A first side array of radiating elements is provided as a first plurality of rows and columns of radiating elements on the first side reflector panel. A second side array of radiating elements is provided as a second plurality of rows and columns of radiating elements on the second side reflector panel. A multi-beam generator is also provided, which is electrically coupled to the radiating elements in the first side array, the central array and the second side array. This multi-beam generator is configured to: (i) drive the first plurality of rows and columns of radiating elements with RF signals in a first frequency band that support generation of a first beam, which is generally aligned with a first azimuth boresight pointing direction; (ii) drive the second plurality of rows and columns of radiating elements with RF signals in the first frequency band that support generation of a second beam, which is generally aligned with a second azimuth boresight pointing direction that is different than the first azimuth boresight pointing direction; (iii) drive the radiating elements in the central array with RF signals in the first frequency band that support generation of a third beam, which is generally aligned with a third azimuth bo resight pointing direction that is different than both the first and second azimuth boresight pointing directions; and (iv) drive the radiating elements in the central array with RF signals in a second frequency band outside the first frequency band.

[0016] A base station antenna according to a further embodiment of the invention includes a reflector having at least three generally forward facing reflector panels, including a central reflector panel, a first side reflector panel extending rearward ly at a first acute angle relative to a front facing surface of the central reflector panel, and a second side reflector panel extending rearwardly at a second acute angle relative to the front facing surface of the central reflector panel. A multi-beam generator is provided, which is electrically coupled to an array of radiating elements on the first side, central and second side reflector panels. This multi-beam generator is configured as: (i) a dual- beam generator with respect to first RF signals in a frequency band, which are provided to radiating elements on the first and second side reflector panels, and (ii) a multi- column beamformer with respect to second RF signals in the frequency band, which are provided to multiple columns of radiating elements on the central reflector panel.

BRIEF DESCRIPTION OF THE DRAWINGS [0017] FIG. 1 is an azimuth pattern illustrating how the azimuth pointing direction and the azimuth HPBW of the antenna beams formed by a conventional twin beam base station antenna, which includes a Butler Matrix style beamforming network, change with increasing frequency.

[0018] FIG. 2 is a schematic transverse cross-sectional view of a conventional multi- column mechanically-steered twin beam base station antenna.

[0019] FIG. 3A is a plan view base station antenna according to an embodiment of the invention.

[0020] FIG. 3B is a schematic transverse cross-sectional view of the base station antenna of FIG. 3A taken along line 3B-3B’, according to an embodiment of the invention.

[0021] FIG. 4A is a schematic transverse cross-sectional view of a tri-beam base station antenna according to an embodiment of the invention. [0022] FIG. 4B is a block diagram illustrating an embodiment of the multi-beam generator of FIG. 4A.

[0023] FIG. 4C is a schematic transverse cross-sectional view of a tri-beam and center dual-beam base station antenna according to an embodiment of the invention.

[0024] FIG. 4D is a block diagram illustrating an embodiment of the multi-beam generator of FIG. 4C.

[0025] FIG. 4E is a schematic transverse cross-sectional view of a tri-beam and side dual-beam base station antenna according to an embodiment of the invention.

[0026] FIG. 4F is a block diagram illustrating an embodiment of the multi-beam generator of FIG. 4E.

[0027] FIG. 4G is a schematic transverse cross-sectional view of a tri-beam, side dual- beam and center beamformer base station antenna according to an embodiment of the invention.

[0028] FIG. 5A is a plan view base station antenna according to an embodiment of the invention.

[0029] FIG. 5B is a schematic transverse cross-sectional view of the base station antenna of FIG. 5A taken along line 5B-5B’, according to an embodiment of the invention.

[0030] FIG. 6A is a plan view base station antenna according to an embodiment of the invention.

[0031] FIG. 6B is a schematic transverse cross-sectional view of the base station antenna of FIG. 6A taken along line 6B-6B’, according to an embodiment of the invention.

DETAILED DESCRIPTION

[0032] The present invention now will be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as being 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 reference numerals refer to like elements throughout.

[0033] It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

[0034] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms "a, II II 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 "comprising", "including", "having" and variants thereof, when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. In contrast, the term "consisting of' when used in this specification, specifies the stated features, steps, operations, elements, and/or components, and precludes additional features, steps, operations, elements and/or components.

[0035] 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 the present invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0036] Referring now to FIGS. 3A-3B, a base station antenna 100 according to one exemplary embodiment is illustrated as including a multi-panel reflector 110 having a plurality of rows and columns of radiating elements 104 (e.g., slant -45°/+45° cross- polarized dipole radiators) thereon, which are enclosed within an antenna housing 102 (e.g., radome). These radiating elements 104 may be configured to support radio frequency (RF) radiation across a relatively wide frequency range (e.g., 1695-2690 MHz) and one or more sub-bands thereof. As shown, the multi-panel reflector 110 may be sufficiently sized to support a relatively large array of radiating elements 104, which are arranged into twenty rows (R1-R20) spanning ten columns (C1-C10). And, as shown best by FIG. 3A, each odd row (R1, R3, ..., R19) may be aligned to span odd columns C1 , C3, C5, C7 and C9, whereas each even row (R2, R4, ..., R20) may be aligned to span even columns C2, C4, C6, C8 and C10. Thus, the radiating elements 104 in the array may collectively define ten staggered (e.g., zig-zag) rows of radiating elements 104 containing ten radiating elements 104 per staggered row, which span the ten columns C1-C10. Moreover, based on the “zig-zag” arrangement of the rows and columns, each radiating element has at least one nearest neighbor radiating element in an adjacent row and column. For example, each radiating element 104 in the even rows R2, R4, ..., R20 of column C4 has at least one corresponding nearest neighbor radiating element 104 in an odd row (e.g., R1, R3, .... R19) of column C3. Similarly, each radiating element 104 in the even rows R2, R4. R20 of column C7 has at least one corresponding nearest neighbor radiating element 104 in an odd row (e.g., R1, R3, ..., R19) of column C8.

[0037] The multi-panel reflector 110 is illustrated as including three (3) generally forward facing reflector panels 110a, 110b and 110c. As shown, a first side reflector panel 110a supports three columns C1-C3 of radiating elements 104, a second side reflector panel 110c supports three columns C8-C10 of radiating elements 104, and a central reflector panel 110b supports four columns C4-C7 of radiating elements 104. As shown by FIG. 3B, the first side reflector panel 110a extends generally rearwardly at a first acute angle (on) relative to a front facing surface of a central reflector panel 110b, whereas the second side reflector panel 110c extends generally rearwardly at a second acute angle («2) relative to the front facing surface of the central reflector panel 110b. According to some embodiments, the three panels of the reflector 110 may be configured such that the first and second acute angles αn, α12 are provided in a range from 20° to 40°. The magnitude of these angles α1, α2 can depend on antenna application and a desired degree of mechanical and/or electrical beam steering required and supported by a multi-beam generator 120, which is coupled to and drives the radiating elements 104 in the array with RF transmission signals, as explained more fully hereinbelow. And, although FIG. 3B illustrates a multi-beam generator 120 provided within the antenna housing 102, one or more components of the multi-beam generator 120 may be provided outside the housing 102 in alternative embodiments of the invention.

[0038] As will be understood by those skilled in the art, a three panel reflector 110 with acute angles of 40° will cause a first group of radiating elements 104 in columns C1-C3 to point towards a -40° sub-sector (of a 120° sector) relative to the radiating elements 104 spanning columns C4-C7, and a second group of radiating elements 104 in columns C8-C10 to point towards a +40° sub-sector. Stated alternatively, a difference in the azimuth boresight pointing direction of the first group of radiating elements 104 in columns C1-C3 (or second group of radiating elements 104 in columns C8-C10) relative to the radiating elements 104 on the central reflector panel 110b may be mechanically established at 40° to thereby divide a 120° sector into three equivalent 40° sub-sectors in the azimuth plane of the antenna 100.

[0039] Referring now to FIG. 4A, an embodiment of the base station antenna 100 of FIG. 3B is illustrated as base station antenna 100a, which includes a tri-beam RF generator 120a. As shown, this tri-beam generator 120a drives radiating elements 104 (e.g., cross-polarized dipole radiators) in all rows and columns of the base station antenna 100 of FIG. 3A via output ports 1-10 (corresponding to columns C1-C10), in response to RF input signals associated with a first frequency band. In some embodiments, the first frequency band may span frequencies from 1695-2690 MHz, for example, or a subset thereof (e.g., 2300-2690 MHz).

[0040] In particular, the tri-beam generator 120a utilizes RF input signals to be transmitted to generate three sub-sector beams, which collectively span a corresponding 120° sector in the azimuth plane. These three beams are illustrated as a left beam 122a, which is generated by columns C1-C3 and C4 of the radiating elements 104, a center beam 122b, which is generated by columns C4-C7 of the radiating elements 104, and a right beam 122c, which is generated by columns C7 and C8-C10 of the radiating elements 104. Based on this configuration, ports 4 and 7 of the tri-beam generator 120a drive columns C4 and C7 of the radiating elements 104 with RF signals associated with a pair of spaced-apart beams, including portions of beams 122a, 122b with respect to column C4 and portions of beams 122b, 122c with respect to column C7. Although not wishing to be bound by any particular configuration, the tri-beam generator 120a may utilize power dividers (e.g., Wilkinson-type, not shown) to generate RF signals, which are provided from ports 4 and 7 to columns C4 and C7, respectively. Moreover, in the event the acute angles α1, α2 are reduced to as little as 20° to thereby reduce the front-to-rear “height” of the reflector 110, the tri-beam generator 120a may utilize electronic beam-steering components (not shown) so that the left and right beams 122a and 122c maintain a 40° offset relative to the center beam 122b.

[0041] FIG. 4B is a block diagram illustrating an embodiment of the multi-beam generator 120a of FIG. 4A. As shown in FIG. 4B, the multi-beam generator 120a has first through third RF inputs 121a, 121 b, 121c that may receive respective first through third RF signals. The first RF input 121a is connected to a first feed network 123a that sub-divides the first RF signals input thereto and feeds these sub-components to the radiating elements 104 in columns C1 through C4. The first feed network 123a may also apply relative phase shifts to the sub-components that are fed to different of the radiating elements 104 in columns C1 through C4 in order to electronically steer the antenna beam generated by the radiating elements 104 in columns C1-C4 in response to the RF signals input at the first RF input 121a. The second RF input 121 b is connected to a second feed network 123b that sub-divides the RF signals input thereto and feeds these sub-components to the radiating elements 104 in columns C4 through C7. The second feed network 123b may also apply relative phase shifts to the sub- components that are fed to different of the radiating elements 104 in order to electronically steer the antenna beam generated by the radiating elements 104 in columns C4-C7 in response to the RF signals input at the second RF input 121b. The third RF input 121c is connected to a third feed network 123c that sub-divides the RF signals input thereto and feeds these sub-components to the radiating elements 104 in columns C7 through C10. The third feed network 123c may also apply relative phase shifts to the sub-components that are fed to different of the radiating elements 104 in order to electronically steer the antenna beam generated by the radiating elements 104 in columns C7-C10 in response to the RF signals input at the third RF input 121c.

[0042] As noted above, and as shown in FIG. 4B, power dividers (PD) 125a such as, for example, Wilkinson power dividers, may be provided. These power dividers 125a are configured to combine sub-components of the RF signals output by the first feed network 123a and sub-components of the RF signals output by the second feed network 123b; and these combined signals are fed to the radiating elements 104 of column C4 so that column C4 is "shared" by the first and second feed networks 123a, 123b. Likewise, power dividers 125b may be provided that combine sub-components of the RF signals output by the second feed network 123b and sub-components of the RF signals output by the third feed network 123c; and these combined signals are fed to the radiating elements 104 of column C7 so that column C7 is "shared" by the second and third feed networks 123b, 123c.

[0043] Referring now to FIG. 4C, a multi-beam generator 120b may be provided, which includes all the components of the tri-beam generator 120a of FIG. 4A as well as typical components (such as, for example, a Butler Matrix) of a multi-column dual-beam antenna and signal combiners/diplexers, not shown, to thereby yield a base station antenna 100b having both mechanically-steered tri-beams 122a, 122b and 122c associated with a first frequency band (e.g., 2300-2690 MHz) and an electronically- steered twin-beam associated with the second non-overlapping frequency band (e.g., 1695-2180 MHz). Examples of multi-column twin-beam antennas that utilize Butler Matrix components are illustrated and described more fully in the aforementioned and commonly-assigned PCT Patent Application No. PCT/CN2019/092788 and in commonly-assigned U.S. Patent No. 9,831 ,548 to Timofeev et al, the disclosures of which are hereby incorporated herein by reference. As shown, the four central columns C4 to C7 of radiating elements 104 can be controlled to generate a pair of “sector- splitting” beams (left beam 124a, right beam 124b), in addition to contributing to the generation of the three beams 122a, 122b and 122c described with respect to FIG. 4A. [0044] FIG. 4D is a block diagram illustrating an embodiment of the multi-beam generator 120b of FIG. 4C. As shown in FIG. 4D, the multi-beam generator 120b includes the first through third RF inputs 121a-121c and the first through third feed networks 123a-123c that are described above with reference of FIG. 4B, and hence further description of these components will be omitted. Additionally, the multi-beam generator 120b also includes a fourth feed network 123d that is coupled to fourth and fifth RF inputs 121d, 121e. The fourth feed network 123d is connected to columns C4 through C7 of radiating elements 104 and includes a Butler Matrix that generates a pair of antenna beams having nominal 60 degree azimuth HPBWs in response to RF signals input at the fourth and fifth RF inputs 121 d, 121e. Additionally, the radiating elements 104 in columns C4 through C7 are coupled to diplexers 127 that combine (in the transmit direction) and separate (in the receive direction) the first frequency band signals that are fed to columns C4 through C7 from the first through third RF inputs 121a-121c with the second frequency band signals that are fed to columns C4 through C7 from the fourth and fifth RF inputs 121d, 121e.

[0045] Referring now to the base station antenna 100c of FIG. 4E, a multi-beam generator 120c may be provided, which performs the functions of the tri-beam generator 120a of FIG. 4A, but also includes additional components to support the generation of twin antenna beams 126a (left) and 126b (right) in a second frequency band, using columns C1-C3 and C8-C10, respectively. This second frequency band may span a range of frequencies that is non-overlapping relative to the first frequency band. For example, in some embodiments, the first frequency band (RF Band 1) may span a range of frequencies from 2300-2690 MHz and the second frequency band (RF Band 2) may span a lower range of frequencies from 1695-2180 MHz. Moreover, unlike the left, center and right beams 122a, 122b and 122c, which may have respective azimuth pointing directions of -40°, 0° and +40°, the phases of the RF signals associated with the twin beams 126a (left) and 126b (right) may be adjusted by the generator 120c so that the azimuth pointing directions of these beams may be less than a = 40° (e.g., -27° and +27°).

[0046] FIG. 4F is a block diagram illustrating an embodiment of the multi-beam generator 120c of FIG. 4E. As shown in FIG. 4F, the multi-beam generator 120c includes the first through third RF inputs 121a-121c and the first through third feed networks 123a-123c that are described above with reference of FIG. 4B, and hence further description of these components will be omitted. Additionally, the multi-beam generator 120b also includes a sixth feed network 123f that is coupled to a sixth RF input 121 f and a seventh feed network 123g that is coupled to a seventh RF input 121g. The sixth feed network 123f is connected to columns C1 through C3 of radiating elements 104 and diplexers 127 are provided that combine (in the transmit direction) and separate (in the receive direction) the first frequency band signals with the second frequency band signals that are fed to these columns. Similarly, the seventh feed network 123g is connected to columns C8 through C10 of radiating elements 104 and diplexers 127 are provided that combine (in the transmit direction) and separate (in the receive direction) the first frequency band signals with the second frequency band signals that are fed to these columns.

[0047] Next, as shown by the base station antenna 100d of FIG. 4G, a multi-beam generator 120d may be provided, which includes all of the elements the base station antenna 100c of FIG. 4E. As discussed above, these elements may be used to generate tri-beam antenna beams 122a-122c in the first frequency band and twin beams 126a, 126b on the left and right sides of the reflector 110 in the second frequency band (RF Band 2A). In addition, base station antenna 100d includes a four column beamformer antenna that uses columns C4 through C7 to generate a beamformer beam 128 within the second frequency band (RF Band 2B). Alternatively, in another embodiment, the tri-beam generation associated with the multi-beam generator 120d may be omitted, the 3-column twin beams 126a, 126b on the left and right sides of the reflector 110 may be generated within a relatively wide frequency band (e.g., 1695-2690 MHz) and the central 4-column beamformer beam 128 may be generated in a somewhat narrower frequency band (e.g., 2300-2690 MHz).

[0048] As will be understood by those skilled in the art, the use of beamforming in base station antennas offers several advantages over the -40°, 0° and +40° tri-beam sectorized antenna beam patterns described with respect to FIG. 4A, or the -30° and +30° twin-beam sectorized antenna beam patterns described with respect to FIG. 4C where the channel resources designated for a specific user are broadcast over a full sub-sector. In contrast, with beamforming, the use of a directive beam focuses the transmitted signal strength (and receiver sensitivity) in the direction of an intended wireless link, which increases the antenna gain (and hence throughput) to the intended user. Another significant benefit is that use of a directive antenna beam reduces interference with other mobile users by minimizing radiation in directions other than the intended direction.

[0049] A beamforming antenna array is generally comprised of many individual radiating elements or sub-arrays of radiating elements. Each element or sub-array of elements is connected to an individual transmitter/receiver channel (not shown). The more elements that are arrayed generally results in a narrower beam (i.e., smaller HPBW) and higher gain at the peak of the beam. Since each antenna element is transmitting or receiving a portion of the signal, the signals transmitted or received from some angles will add in-phase as the channels are combined, whereas signals from other angles will subtract and thereby cancel each other. The carrier frequency radiated by each element of the array combines either constructively or destructively across various angles to form peaks and nulls in the antenna beam. If the delay through each channel is equal, then the peak of the antenna beam will point directly perpendicular to the array, in alignment with the array’s boresight angle. By progressively increasing the electrical delay across the elements of the array, the peak of the antenna beam can be positioned at an angle that is offset from the boresight angle. Therefore, by carefully controlling the relative electrical delay through each transmitter/receiver path to each of the radiator elements, an antenna beam(s) can effectively be electrically steered across a wide angular range. And, using advanced acquisition and tracking algorithms, the angle for each mobile user is determined and tracked to ensure the user receives the strongest signal with minimum interference.

[0050] Referring now to FIGS. 5A-5B, a base station antenna 100’ according to another embodiment includes the components of the antenna 100 of FIGS. 3A-3B, along with two columns of relatively low band radiating elements 108 (e.g., slant -45°/+45° cross- polarized dipole radiators that operate in the 694-960 MHz frequency band), which are supported by and extend along opposing sides of the center reflector panel 110b. As will be understood by those skilled in the art, these two columns of radiating elements 108 may be utilized to each provide service to the full 120° sector in two portions of the low band or to provide 4xMIMO service in the low band. The multi-beam generator 120e, which is illustrated as having two additional RF output ports to independently support the two columns of radiating elements 108, may also include the components and functionality described hereinabove with respect to any of FIGS. 4A-4G. In other embodiments, only a single column of low band radiating elements may be provided. [0051] Referring now to the base station antenna 100” of FIGS. 6A-6B, the antenna 100’ of FIGS. 5A-5B may be further modified to include three columns of the relatively low band radiating elements 108, with each column being commonly aligned and supported by a respective one of the left, center and right reflector panels 110a, 110b and 110c. In particular, the three columns of radiating elements 108 may be controlled by a multi-beam generator 120f to thereby generate a pair of sector-splitting beams having ±30° azimuth pointing angles relative to a normal to the center reflector panel 110b. These beams are illustrated as left beam 130a, which is generated by the leftmost and center columns of radiating elements 108, and right beam 130b, which is generated by the center and rightmost columns of radiating elements 108. The multi- beam generator 120f, which is illustrated as having three additional RF output ports to independently support the three columns of radiating elements 108, may also include the components and functionality described hereinabove with respect to any of FIGS. 4A-4G.

[0052] In the drawings and specification, there have been disclosed typical preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims.