Dual beam base station antenna with curved radiator arms

Abstract

Dual-beam base station antennas are provided. The dual-beam base station antennas include a plurality of vertical columns of radiating elements configured to transmit radio frequency signals of a frequency band. The radiating elements have curved metal radiator arms that include a tip portion facing a respective central axis of the radiating element.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to radio communications, and more particularly to dual-beam base station antennas for use in cellular and other communication systems. BACKGROUND

[0002] Cellular communication systems are well known in the art. In a typical cellular communication system, a geographic region is divided into a series of areas called "cells," each of which is served by a base station. The base station can include baseband equipment, radios, and a base station antenna that is configured to provide two-way radio frequency ("RF") communication with users located throughout the cell. In many cases, the cell can be divided into multiple "sectors," and separate base station antennas provide coverage for each sector. The base station antennas are typically mounted on a tower or other elevated structure, with the radiated beam ("antenna beam") generated by each antenna pointing outward to serve the corresponding sector. Typically, the base station antennas include one or more phased arrays of radiating elements, with the radiating elements arranged in one or more vertical columns when the antenna is installed for use. "Vertical" herein refers to a direction that is perpendicular with respect to a plane defined by the horizon.

[0003] A common base station configuration is a "three-sector" configuration, in which the cell is divided into three 120° sectors in the azimuthal plane, and the base station includes three base station antennas that provide coverage for the three corresponding sectors. The azimuthal plane refers to a horizontal plane that bisects the base station antenna and is parallel with a plane defined by the horizon. In a three-sector configuration, the antenna beam generated by each base station antenna typically has a half-power beamwidth ("HPBW") in the azimuthal plane of about 65°, such that the antenna beam provides good coverage for the entire 120° sector. Typically, each base station antenna will include a vertically extending column of radiating elements that together generate the antenna beam. Each radiating element in the column can have an HPBW of approximately 65°, such that the antenna beam generated by the column of radiating elements will provide coverage for a 120° sector in the azimuthal plane. The base station antenna can include multiple columns of radiating elements that operate in the same frequency band or different frequency bands.

[0004] Most modern base station antennas also include remotely controlled phase shifter / power divider circuitry along the RF transmission path through the antenna that allows a phase tilt to be applied to the sub-components of the RF signal provided to the radiating elements in the array. By adjusting the amount of phase tilt applied, the resulting antenna beam can be electrically tilted downward in the vertical plane or "elevation" plane to a desired degree. This technique can be used to adjust the distance that the antenna beam extends outward from the antenna, and thus can be used to adjust the coverage area of the base station antenna.

[0005] Sector splitting refers to a technique in which the coverage area of 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 would have six 60° sectors in the azimuth plane. Dividing each 120° sector into two sub-sectors increases system capacity because each antenna beam provides coverage to a smaller area, thus providing higher antenna gain and / or allowing frequency reuse within the 120° sector. In a six-sector sector-splitting application, a single dual-beam antenna is typically used for each 120° sector. A dual-beam antenna generates two separate antenna beams that each have a reduced size in the azimuth plane and that each point in a different direction in the azimuth plane, thereby dividing the sector into two smaller sub-sectors. The antenna beams produced by a dual-beam antenna for a six-sector configuration preferably have an azimuthal HPBW value of, for example, between about 27°-39°, and the pointing directions of the first and second sector-splitting antenna beams in the azimuth plane are typically about -27° and about 27°, respectively, from the 0° "azimuthal boresight pointing direction" of the antenna, which refers to the horizontal axis extending from the base station antenna that points in the azimuth plane to the center of the sector served by the base station antenna.

[0006] Several approaches have been used to implement a dual-beam antenna that provides coverage for the respective first and second sub-sectors of a 120° sector in the azimuth plane. In a first approach, first and second columns of radiating elements are mounted on the two major interior faces of a V-shaped reflector. The angle defined by the interior faces of the V-shaped reflector can be about 54°, such that the two columns of radiating elements are mechanically positioned or "steered" to point at about -27° and 27° azimuth, respectively (i.e., toward the middle of the respective sub-sectors). Since the azimuthal HPBW of a typical radiating element is generally adapted to cover the entire 120° sector, an RF lens is mounted in front of the two columns of radiating elements that narrows the azimuthal HPBW of each antenna beam by an appropriate amount to provide coverage for a 60° sub-sector. Unfortunately, however, the use of an RF lens can increase the size, weight, and cost of the base station antenna, and the amount by which the RF lens narrows the beamwidth is a function of frequency, making it difficult to obtain suitable coverage when using wideband radiating elements that operate over a wide frequency range (e.g., radiating elements that operate over the entire 1.7-2.7 gigahertz ("GHz") cellular frequency range).

[0007] In a second approach, two or more columns of radiating elements (typically 2-4 columns) are mounted on a planar reflector such that each column points in the azimuthal look direction of the antenna. Two RF ports (per polarization) are coupled to all columns of radiating elements 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 the look direction of the antenna by about -27° and 27° in azimuth to provide coverage to two subsectors. With such a beamforming network based dual-beam antenna, the pointing angle in the azimuthal plane of each antenna beam and the HPBW of each antenna beam can vary as a function of frequency of the RF signals input at the two RF ports. Specifically, the azimuthal pointing direction (i.e., the azimuthal angle at which peak gain occurs) of the antenna beams tends to move toward the azimuthal look direction of the antenna, and the azimuthal HPBW tends to become smaller as frequency increases. This can result in large variations in power level of the antenna beams at the outer edges of the subsectors as a function of frequency, which is undesirable.

[0008] In a third approach, a multi-column array of radiating elements (typically three columns per array) is mounted on each outer panel of a V-shaped reflector to provide a sector-split dual-beam antenna. The antenna beams generated by each multi-column array can vary less as a function of frequency compared to both the lens-type dual-beam antenna and the beamforming based dual-beam antenna discussed above. Unfortunately, this sector-split antenna can require a large number of radiating elements, which increases the cost and weight of the antenna. In addition, including six columns of radiating elements can increase the required width of the antenna, and the V-shaped reflector can increase the depth of the antenna, both of which can be undesirable.

[0009] In general, a cellular operator would like the azimuthal HPBW value of a dual-beam antenna to be anywhere between 30°-38°, as long as the azimuthal HPBW value does not vary significantly (e.g., more than 12°) across the entire operating frequency band. Likewise, the azimuthal pointing angle of the antenna beam peak can vary anywhere between + / - 26° to + / - 33°, as long as the azimuthal pointing angle does not vary significantly (e.g., more than 4°) across the entire operating frequency band. The peak azimuthal side lobe level should preferably be at least 15 decibels ("dB") lower than the peak gain value. SUMMARY

[0010] According to embodiments of the present application, a dual-beam base station antenna is provided that can include a reflector. The dual-beam base station antenna can include a plurality of vertically interleaved vertical columns of radiating elements on a surface of the reflector and configured to transmit RF signals of a frequency band. A metallic radiator arm of each of the radiating elements can include a base portion parallel to the surface of the reflector and a tip portion non-parallel to the surface of the reflector. Further, a shortest distance between consecutive ones of the vertical columns is greater than 8.4 millimeters.

[0011] In some embodiments, each of the radiating elements can include a printed circuit board ("PCB") parallel to the surface of the reflector. The base portion of the metallic radiator arm can be on the PCB. Further, the tip portion of the metallic radiator arm can protrude away from or toward the surface of the reflector.

[0012] According to some embodiments, the tip portion can be a first tip portion of a plurality of tip portions of a respective metallic arm on the PCB. For example, both the first tip portion of the tip portions and a second tip portion of the tip portions can protrude away from the surface of the reflector. As another example, both the first tip portion of the tip portions and the second tip portion of the tip portions can protrude toward the surface of the reflector. In yet another example, the first tip portion of the tip portions can protrude away from the surface of the reflector and the second tip portion of the tip portions can protrude toward the surface of the reflector.

[0013] In some embodiments, the dual-beam base station antenna can include a conductive plate on the PCB and coupling the base portion of the metallic radiator arm to the PCB. The conductive plate and the base portion of the metallic radiator arm can be different metals, respectively. Further, the conductive plate can be a copper plate.

[0014] According to some embodiments, a widest dimension of each of the radiating elements can be no more than 68 millimeters in a direction parallel to the surface of the reflector.

[0015] In some embodiments, the vertical columns can include a first vertical column, a second vertical column, a third vertical column, and a fourth vertical column, and the first vertical column and the third vertical column can be vertically interleaved relative to the second vertical column and the fourth vertical column. Further, the first vertical column and the second vertical column can be spaced apart from each other by at least 35 millimeters.

[0016] According to some embodiments, the base portion of the metal radiator arm and the tip portion of the metal radiator arm can be adjoining portions of a continuous sheet of metal, and opposite edge regions of the base portion can be planar.

[0017] According to some embodiments, a dual-beam base station antenna can include a plurality of vertically-interleaved vertical columns of radiating elements configured to transmit RF signals of a frequency band, and having curved metal radiator arms including tip portions facing respective central axes of the radiating elements.

[0018] In some embodiments, successive ones of the vertical columns can be spaced apart from each other by at least 30 millimeters.

[0019] According to some embodiments, first and second ones of the tip portions can protrude in opposite directions, respectively. Moreover, the dual-beam base station antenna can include a reflector, the radiating elements can be on a surface of the reflector, and each of the opposite directions can be non-parallel to the surface of the reflector.

[0020] According to some embodiments, a dual-beam base station antenna can include a reflector. The dual-beam base station antenna can include first and second vertical columns of radiating elements on a surface of the reflector and configured to transmit RF signals of a frequency band. A first metal dipole arm of a first radiating element of the first vertical column can include a first tip portion protruding away from the surface of the reflector. Moreover, a second metal dipole arm of a second radiating element of the second vertical column can include a second tip portion protruding toward the surface of the reflector.

[0021] In some embodiments, a third metal dipole arm of the first radiating element can include a third tip portion protruding toward the surface of the reflector.

[0022] According to some embodiments, the dual-beam base station antenna can include third and fourth vertical columns of radiating elements on the surface of the reflector and configured to transmit RF signals of the frequency band. The first, second, third, and fourth vertical columns can be successive vertical columns. The first and third vertical columns can be vertically interleaved with respect to the second and fourth vertical columns. The second tip portion can be closer to the first tip portion than any other tip portion of the first vertical column. Moreover, a shortest distance between the first and second vertical columns can be longer than a length of the first tip portion. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Front perspective view of a base station antenna according to embodiments of the application.

[0024] Figure 2A is a front view of an antenna assembly of a prior art base station antenna.

[0025] Figure 2B is an enlarged partial front view of the antenna assembly of Figure 2A.

[0026] Figure 2C is an enlarged outline view of a radiating element of Figure 2B.

[0027] Figure 2D is a front view of the radiating element of Figure 2C.

[0028] Figure 3A is a front view of an antenna assembly of another prior art base station antenna.

[0029] Figure 3B is an enlarged partial front view of the antenna assembly of Figure 3A.

[0030] Figure 4A Figure 4A is a front view of an antenna assembly of a dual-beam base station antenna according to embodiments of the application.

[0031] Figure 4B Figure 4B is an enlarged partial front view of the antenna assembly of Figure 4A. Figure 4A

[0032] Figure 4C Figure 4C is an enlarged front view of a radiating element of Figure 4A. Figure 4B

[0033] Figure 4D Figure 4D is an outline view of the radiating element of Figure 4A. Figure 4C

[0034] Figure 4E Figure 4E is an outline view of the radiating element of Figure 4A having a tip portion that protrudes upward. Figure 4C

[0035] Figure 4F Figure 4F is an outline view of the radiating element of Figure 4A having tip portions that protrude in different directions. Figure 4C DETAILED DESCRIPTION

[0036] ​​​​​According to embodiments of the present application, improved dual-beam base station antennas are provided that overcome or mitigate various difficulties with columns of radiating elements of conventional base station antennas. Dual-beam antennas according to embodiments of the present application can include compact radiating elements having relatively large column-to-column spacing. For example, the radiating elements can have curved metal radiator arms. In particular, tip portions of the radiator arms that conventionally extend outwardly toward adjacent columns of radiating elements can instead protrude upwardly or downwardly, thus reducing the size (e.g., width) of the radiating elements. Thus, dual-beam base station antennas according to embodiments of the present application can improve antenna performance, for example, by reducing mutual coupling between adjacent columns of radiating elements.

[0037] The radiating elements can be, for example, dual-polarized radiating elements. Each dual-polarized radiating element includes a first polarized radiator and a second polarized radiator. The most commonly used dual-polarized radiating element is a cross-dipole radiating element that includes a tilt -45° dipole radiator and a tilt +45° dipole radiator. The tilt -45° dipole radiator of each cross-dipole radiating element in a column is coupled to a first (-45°) RF port, and the +45° dipole radiator of each cross-dipole radiating element in the column is coupled to a second (+45°) RF port. This column of cross-dipole radiating elements will produce a first -45° polarized antenna beam in response to RF signals input at the first RF port, and will produce a second +45° polarized antenna beam in response to RF signals input at the second RF port. Exemplary dual-polarized dipole radiating elements are discussed in International Patent Application No. PCT / US2020 / 023106, the disclosure of which is incorporated herein in its entirety. However, it will be recognized that in other embodiments any suitable radiating element can be used, including, for example, single-polarized dipole radiating elements or patch radiating elements.

[0038] Figure 1 is a front perspective view of a base station antenna 100 according to embodiments of the present application. The antenna 100 can be, for example, a cellular base station antenna at a macrocell base station. However, it will be recognized that the techniques disclosed herein can also be applied to other base station antennas, such as small cell base station antennas. As shown in FIG. 1, the antenna 100 includes a plurality of columns of radiating elements 102. Each column of radiating elements 102 includes a plurality of dual-polarized radiating elements 104. Each dual-polarized radiating element 104 includes a first polarized radiator and a second polarized radiator. In the example shown in FIG. 1, each dual-polarized radiating element 104 is a cross-dipole radiating element that includes a tilt -45° dipole radiator and a tilt +45° dipole radiator. The tilt -45° dipole radiator of each cross-dipole radiating element 104 in a column is coupled to a first (-45°) RF port, and the +45° dipole radiator of each cross-dipole radiating element 104 in the column is coupled to a second (+45°) RF port. This column of cross-dipole radiating elements 104 will produce a first -45° polarized antenna beam in response to RF signals input at the first RF port, and will produce a second +45° polarized antenna beam in response to RF signals input at the second RF port. Exemplary dual-polarized dipole radiating elements are discussed in International Patent Application No. PCT / US2020 / 023106, the disclosure of which is incorporated herein in its entirety. However, it will be recognized that in other embodiments any suitable radiating element can be used, including, for example, single-polarized dipole radiating elements or patch radiating elements. Figure 1As shown, the antenna 100 is an elongated structure and has a generally rectangular shape. The antenna 100 includes a radome 110. In some embodiments, the antenna 100 also includes a top end cap 120 and / or a bottom end cap 130. The bottom end cap 130 can include a plurality of RF connectors 140 mounted therein. The connectors 140 can also be referred to herein as “ports,” but the connectors are not limited to being on the bottom end cap 130. Rather, one or more of the connectors 140 can be disposed on a back (i.e., rear) side of the radome 110, for example, opposite a front side of the radome 110. The antenna 100 is typically installed in a vertical configuration (i.e., the long sides of the antenna 100 extend along a vertical axis L with respect to the ground).

[0039] The connectors 140 can be coupled to groups of radiating elements 450 by a beamforming network, such as a Butler Matrix or other beamforming circuitry. Figure 4A Exemplary arrays and beamforming networks coupled thereto are discussed in International Publication No. WO 2020 / 027914, the disclosure of which is hereby incorporated by reference herein in its entirety.

[0040] FIG. 2A is a front view of an antenna assembly 200 of a prior art base station antenna. In particular, FIG. 2A shows that the antenna assembly 200 includes one or more groups of radiating elements 250, such as arrays or sub-arrays. For example, some or all of the radiating elements 250 can be in vertical columns that are spaced apart from one another in a horizontal direction H. The operation of the antenna of FIG. 2A is described in detail in U.S. Patent No. 9,831,548, the entirety of which is incorporated herein by reference. As shown in FIG. 2A, the radiating elements 250 are arranged in rows, but some of the rows have different numbers of radiating elements. Thus, the vertical columns of radiating elements include some degree of staggering in the horizontal direction H, and not all of the columns have the same number of radiating elements. This arrangement can facilitate producing antenna beams having a desired azimuth HPBW.

[0041] FIG. 2B is an enlarged partial front view of the antenna assembly 200 of FIG. 2A. As shown in FIG. 2B, adjacent vertical columns of radiating elements 250 have a shortest distance dl between them in the horizontal direction H. For example, the distance dl can be 8.4 millimeters (“mm”). Because this distance is relatively short, strong mutual coupling can occur between the radiating elements 250 of adjacent vertical columns. The mutual coupling between adjacent columns of radiating elements 250 can tend to be strongest at the lower end of the operating band of the radiating elements 250, as lower frequencies have smaller separations between columns in terms of wavelengths. For example, for radiating elements 250 operating in a 1,695-2,690 megahertz (“MHz”) band, the mutual coupling between vertical columns of radiating elements can tend to be strongest at 1,695 MHz. The stronger the mutual coupling, the greater the distortion in the azimuth beamwidth of the antenna beam. In addition, strong mutual coupling also results in an undesirable increase in cross-polarization ratio (“CPR”), which is a measure of how much the polarization purity of the antenna beam is distorted. In addition, mutual coupling can also result in the production of high grating lobes in the higher portion of the operating band (e.g., for the above-described radiating elements 250 operating in the 1,695-2,690 MHz band, at frequencies above 2,400 MHz).

[0042] Each radiating element 250 can be on a front surface 230F of a reflector 230 of the antenna. In some embodiments, one or more groups of radiating elements 250 can share a feed panel 240 on the reflector 230. For example, the radiating elements 250 can all be on the same feed panel 240, or different arrays / subarrays of radiating elements 250 can be on respective feed panels 240.

[0043] FIG. 2C is an enlarged profile view of one of the radiating elements 250 of FIG. 2B. When a base station antenna including the antenna assembly 200 is installed for use, the radiating elements 250 will be rotated 90° from the orientation shown in FIG. 2C. The radiating elements 250 can include a pair of PCB feed stalks 251 extending from the front surface 230F of the reflector 230 in the forward direction F. In addition, the radiating elements 250 can include a radiator PCB 252 on the feed stalks 251 and positioned to extend parallel to the front surface 230F of the reflector 230.

[0044] FIG. 2D is a front view of the radiating element 250 of FIG. 2C. As shown in FIG. 2D, the radiating element 250 can include a plurality of planar dipole arms 253 on the PCB 252. The widest dimension Dl of the radiating element 250 (here, the dimension is the distance along the diagonal defined by each dipole radiator) can be, for example, 92.8 mm.

[0045] Figure 3A is a front view of an antenna assembly 300 of another prior art base station antenna. Unlike antenna assembly 200 (Figure 2A) in which radiating elements 250 are arranged in rows, antenna assembly 300 of Figure 3A also includes vertically staggered columns of radiating elements 250, such that there is staggering in both the row and column directions. Specifically, the outermost vertical column in the middle region of assembly 300 is staggered relative to the inner vertical columns therebetween. This staggering of the radiating elements 250 can improve grating lobes that might otherwise be problematic at higher frequencies (e.g., above 2,400 MHz) (e.g., by reducing the amplitude of the grating lobes). However, strong cross-polarization distortion may occur in the high-power region of assembly 300, so the mutual coupling and loss with assembly 300 at 1,695 MHz can be similar to the mutual coupling and loss with assembly 200.

[0046] Figure 3B is an enlarged partial front view of the antenna assembly 300 of Figure 3A. Although they differ in their staggering, antenna assemblies 200 (Figure 2A) and 300 (Figure 3A) can have the same shortest distance d1 between the radiating elements 250 in a continuous vertical column.

[0047] Figure 4A For the dual-beam base station antenna 100 according to an embodiment of the present invention ( Figure 1 Front view of antenna assembly 400. Figure 4A The antenna assembly shown can be slidably inserted. Figure 1 The interior of the radome 110 is shown in the figure. To reduce mutual coupling and improve cross-polarization distortion compared to prior art antenna assemblies 200 (FIG. 2A) and 300 (FIG. 3A), the antenna assembly 400 of antenna 100 includes a vertically staggered column of radiating elements 450 having smaller radiating elements 250 (FIG. 2A and 3A) included in prior art antenna assemblies 200 and 300. Therefore, assembly 400 can provide an antenna beam with improved shape and CPR relative to assemblies 200 and 300. Furthermore, the overall physical aperture of the group of radiating elements 450 (e.g., array / subarray) can be larger, which can improve directivity, and the smaller size of the radiating elements 450 can provide spacing flexibility within assembly 400. For each of antenna assemblies 200, 300 and 400, the vertical or “azimuth” spacing between radiating elements 450 in adjacent rows with four radiating elements (a straight row for antenna assembly 200 and staggered rows for antenna assemblies 300 and 400) in the vertical direction V is maintained at 74 mm to allow for fair performance comparisons between the three different designs.

[0048] Figure 4AThe radiating elements 450 in the antenna assembly 400 are arranged in four adjacent (e.g., contiguous) vertical columns 450C-1 through 450C-4 in the horizontal direction H. Further, the first vertical column 450C-1 and the third vertical column 450C-3 are shown vertically staggered in the vertical direction V relative to the second vertical column 450C-2 and the fourth vertical column 450C-4. The vertical columns 450C of radiating elements 450 can extend in the vertical direction V from a lower portion of the assembly 400 to an upper portion of the assembly 400. The vertical direction V can be the longitudinal axis L, or can be parallel to the longitudinal axis L Figure 1 ). The vertical direction V can also be perpendicular to the horizontal direction H and the forward direction F. As used herein, the term “vertical” does not necessarily require something to be perfectly vertical (e.g., the antenna 100 can have a small mechanical downtilt).

[0049] The vertical columns 450C are each configured to transmit and / or receive RF signals of one or more frequency bands, such as one or more frequency bands including frequencies between 1,427 MHz and 2,690 MHz, or a subset thereof. Although Figure 4A four vertical columns 450C-1 through 450C-4 are shown, the antenna assembly 400 can include more (e.g., five, six, or more) or fewer (e.g., three) vertical columns 450C. Further, the number of radiating elements 450 in the vertical columns 450C can be any number from two to twenty or more. For example, Figure 4A The four vertical columns 450C-1 through 450C-4 shown in FIG. 4 can each have five to twenty radiating elements 450. In some embodiments, the vertical columns 450C can each have the same number (e.g., ten) of radiating elements 450.

[0050] Each radiating element 450 can extend forward from the front surface 430F of the reflector 430 of the antenna 100. In some embodiments, one or more groups of radiating elements 450 can share a feed plate 440 on the reflector 430. For example, the radiating elements 450 can all be on the same feed plate 440, or different arrays / subarrays of radiating elements 450 (e.g., different vertical columns 450C) can be on respective feed plates 440. Typically, one to three radiating elements 450 will be mounted on each feed plate 440, with radiating elements 450 that are mounted together on the same feed plate 440 being adjacent radiating elements 450 in the same column 450C.

[0051] Figure 4B is Figure 4AA magnified partial front view of the antenna assembly 400. Adjacent vertical columns 450C of radiating elements 450 have a minimum distance d2 between them in the horizontal direction H. For example, the distance d2 can be at least 30 mm or at least 35 mm (e.g., 35.3 mm). Therefore, the distance d2 can be significantly longer than the distance d1 between adjacent radiating elements 250 in adjacent vertical columns of the prior art antenna assemblies 200, 300 of Figures 2B and 3B (Figures 2B and 3B).

[0052] In some embodiments, distance d2 may be (a) the first tip portion 453T of the radiating element 450 of the first vertical column 450C-1. Figure 4C (a) The distance between the second tip portion 453T of the radiating element 450 of the second vertical column 450C-2 and (b). Furthermore, since distance d2 is the shortest distance between adjacent vertical columns 450C-1 and 450C-2, the second tip portion 453T can be closer to the first tip portion 453T than any other tip portion of any radiating element 450 of the first vertical column 450C-1.

[0053] Figure 4C for Figure 4B An enlarged front view of the radiating element 450. (See image.) Figure 4C As shown, the radiating element 450 may include a plurality of metal radiator arms 453 on the PCB 452. For example, the radiating element 450 may be a cross-dipole radiating element comprising four metal radiator arms 453-1 to 453-4, such as corresponding sheet dipole arms. Exemplary sheet dipole arms are discussed in U.S. Patent Application No. 16 / 861,427, the disclosure of which is incorporated herein by reference in its entirety. The PCB 452 may include four conductive plates 454 disposed behind the sheet dipole arms 453-1 to 453-4. Each conductive plate 454 may be capacitively coupled to a corresponding sheet dipole arm among the sheet dipole arms 453-1 to 453-4 to transmit RF signals between the feed handle 451 and the sheet dipole arms 453-1 to 453-4. Each radiator arm 453 may include (i) a base portion 453P on a corresponding conductive plate of a conductive plate 454 on the PCB 452, and (ii) a tip portion 453T projecting above or below the PCB 452 in a forward direction F. For example, the base portion 453P may be (e.g., mostly or entirely) on a surface 452F of the PCB 452 parallel to the surface 430F of the reflector 430.

[0054] Accordingly, the base portion 453P can be parallel to the surface 430F, and the tip portion 453T can not be parallel to the surface 430F. Rather, the tip portion 453T can be curved (e.g., angled / folded) relative to the base portion 453P to which it is connected, such that the tip portion 453T faces a central axis 455 Figure 4D ; e.g., an imaginary line), which extends through a center point of the radiating element 450 in the forward direction F. In particular, the tip portion 453T can be perpendicular to the base portion 453P, or can otherwise be angled at 45 degrees or less relative to the central axis 455.

[0055] In some embodiments, the base portion 453P can include an overhang 453PH that extends beyond the outer edge 452E of the PCB 452. Accordingly, in the forward direction F, the PCB 452 is not interposed between the overhang 453PH and the reflector 430.

[0056] In some embodiments, each radiating arm 453 can have only one bend / fold disposed (e.g., defined by) relative to the protruding tip portion 453T. Accordingly, the edge regions 453S of each base portion 453P that are respectively adjacent opposite side edges 452S of the PCB 452 can be planar without being curved upward or downward. Accordingly, the opposite edge regions 453S do not have protrusions therefrom in the forward direction F, but are entirely parallel to the surface 430F of the reflector 430.

[0057] As noted above, the radiating element 450 can include four conductive plates 454 that are on the surface 452F of the PCB 452 and couple the base portion 453P of each metal sheet arm 453P to the PCB 452. In some embodiments, the conductive plates 454 and the base portions 453P can respectively include different metals. For example, the conductive plates 454 can be copper plates, and the base portions 453P can be metal sheets that include aluminum or steel. In some embodiments, the tip portion 453T and the base portion 453P can be adjoining portions of the same continuous metal sheet.

[0058] Because the tip portion 453T of the radiating element 450 is curved relative to the base portion 453P, the PCB 452 having the curved radiating arms 453 thereon can be narrower than the radiator PCB 252 of FIG. 2D, and accordingly, the widest dimension D2 of the radiating element 450 can be significantly narrower than the dimension D1 of the radiating element 250 (FIG. 2D). For example, the dimension D2 can be no more than 68 mm (e.g., 67.8 mm) in a direction parallel to the surface 430F of the reflector 430. Accordingly, the radiating element 450 can be 27% more compact than the radiating element 250, and can therefore provide better isolation performance and better spacing flexibility inside the antenna 100.Figure 1 ).

[0059] Figure 4D for Figure 4C The outline of the radiating element 450. (See diagram below.) Figure 4D As shown, multiple tip portions 453T of the corresponding metal radiator arm 453 can each protrude below the PCB 452 toward the surface 430F of the reflector 430. Thus, the tip portions 453T can face the PCB feed handle 451 and the central axis 455 of the radiating element 450.

[0060] Figure 4E for Figure 4C A contour view of a radiating element 450, the radiating element having an upward curvature relative to the base portion 453P in the forward direction F. Figure 4C ), instead of Figure 4D The downward / backward curved tip portion 453T. Specifically, the tip portion 453T of the corresponding metal radiator arm 453 can each protrude above the PCB 452 away from the surface 430F of the reflector 430. Therefore, the tip portion 453T can face the central axis 455 of the radiating element 450.

[0061] Furthermore, the longest length L of each tip portion 453T can be longer than that of a continuous vertical column 450C ( Figure 4B The distance d2 between ) Figure 4B The length L can be shorter than 35.3 mm and longer than 10 mm. The tip portion 453T can be narrower than the base portion 453P in the direction perpendicular to the length L. In some embodiments, the tip portion 453T and the base portion 453P can have corresponding shapes that generally taper away from the PCB 452 and away from the central axis 455, respectively.

[0062] Figure 4F for Figure 4C A contour drawing of a radiating element 450, the radiating element having a pointed portion 453T curved in a different (e.g., opposite) direction not parallel to the surface 430F of the reflector 430. For example, the first metal radiator arm 453-1 of the radiating element 450 ( Figure 4C The first tip portion 453T-1 and the second metal radiator arm 453-2 of the radiating element 450. Figure 4C The second tip portion 453T-2 of the radiating element 450 can protrude upwards and downwards respectively in the forward direction F. Therefore, the first tip portion 453T-1 protrudes upwards from the surface 430F toward the PCB 452, and the second tip portion 453T-2 protrudes downwards from the surface 430F toward the PCB 452. Similarly, the third metal radiator arm 453-3 and the fourth metal radiator arm 453-4 of the radiating element 450...Figure 4C The tip portion 453T can protrude above and below the PCB 452, respectively. This combination of tip portions 453T protruding in different directions provides better performance than those protruding in the same direction. Figure 4D and 4E The tip portion of the 453T offers even better antenna performance (e.g., better isolation).

[0063] In some embodiments, each radiating element 450 in the antenna assembly 400 ( Figure 4A The element can be a dual-polarized radiating element, such as a cross-dipole radiating element comprising a negatively polarized (e.g., tilted -45°) dipole radiator and a positively polarized (e.g., tilted +45°) dipole radiator. Therefore, in some embodiments, the negatively polarized dipole radiator may include a first metal radiator arm 453-1 and a third metal radiator arm 453-3, and the positively polarized dipole radiator may include a second metal radiator arm 453-2 and a fourth metal radiator arm 453-4, or vice versa.

[0064] Furthermore, in some embodiments, each radiating element 450 in component 400 may have a pointed tip 453T that is bent in different directions. Figure 4F In such embodiments, the radiating element 450 may be arranged such that the closest dipole arms 453 on adjacent radiating elements 450 are arranged such that one dipole arm 453 has an upwardly curved tip portion 453T, and the other dipole arm 453 has a downwardly curved tip portion 453T. In other words, to the extent possible, each dipole arm 453 in the first radiating element 450 has a tip portion 453T that is curved in a different direction relative to the dipole arm 453 of the adjacent radiating element 450. In other embodiments, the tip portion 453T of each radiating element 450 in the assembly 400 may be entirely curved downwards. Figure 4D ) or all bent upwards ( Figure 4E In other embodiments, some of the radiating elements 450 in component 400 (e.g., a vertical column 450C) Figure 4B The tip of 453T can be entirely made of Figures 4D-4F The bending occurs in a specific manner as shown, and the tip portion 453T of the other (e.g., different column 450C) of the radiating element 450 in component 400 can be entirely bent... Figures 4D-4F Another way of bending is shown. For example, the tip portion 453T of the first column 450C-1 can be bent entirely downwards, and the tip portion 453T of the second column 450C-2 can be bent entirely upwards, or vice versa.

[0065] According to an embodiment of the invention, a curved metal radiator arm 453 (Figure 4C Dual-beam base station antenna 100 ( Figure 1 ) can offer many advantages. These advantages include continuous vertical columns 450C ( Figure 4B Radiating element 450 in ) Figure 4B The increased spacing (distance d2) between the radiator arms 453 is due to the tip portion 453T (which is bent relative to the base portion 453P) facilitating the size D2 of each radiating element 450. Figure 4C The increased spacing, along with the vertical stagger of the vertical columns 450C, reduces potentially strong mutual coupling at lower frequencies (e.g., 1,695 MHz). The increased spacing also improves cross-polarization distortion. Reduced mutual coupling and improved cross-polarization distortion allow for improved radiation pattern shape and improved CPR at lower frequencies. Furthermore, the overall physical aperture of a group of radiating elements 450 can be larger, which improves directivity, and the smaller dipole size of the radiating elements 450 provides spacing flexibility to reduce / avoid interference to other frequency bands.

[0066] It will be appreciated that this specification describes only a few exemplary embodiments of the invention, and that the techniques described herein have applicability beyond the exemplary embodiments described above.

[0067] Embodiments of the invention have been described above with reference to the accompanying drawings, in which embodiments of the invention are illustrated. However, the invention may 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. Throughout the text, the same numerals denote the same elements.

[0068] 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 used only to distinguish one element from another. For example, without departing from the scope of the invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0069] 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 can 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 can 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.).

[0070] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. 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.

[0071] Aspects and elements of all the embodiments disclosed above can be combined and / or combined with aspects or elements of other embodiments in any manner possible to provide additional embodiments.

Claims

1. A base station antenna comprising: a reflector; and a plurality of vertically interleaved vertical columns of radiating elements on a surface of the reflector and configured to transmit radio frequency (RF) signals of a frequency band, wherein a metal radiator arm of each of the radiating elements includes a base portion parallel to the surface of the reflector and a tip portion non-parallel to the surface of the reflector, wherein each of the radiating elements includes a printed circuit board (PCB) parallel to the surface of the reflector, wherein the base portion of the metal radiator arm of each of the radiating elements extends over a surface of the PCB, and wherein the tip portion of the metal radiator arm of each of the radiating elements projects away from or toward the surface of the reflector.

2. The base station antenna of claim 1, wherein the tip portion of the metal radiator arm on the PCB of each of the radiating elements includes a first tip portion and a second tip portion.

3. The base station antenna of claim 2, wherein both the first tip portion of the tip portions and the second tip portion of the tip portions project away from the surface of the reflector.

4. The base station antenna of claim 2, wherein both the first tip portion of the tip portions and the second tip portion of the tip portions project toward the surface of the reflector.

5. The base station antenna of claim 2, wherein the first tip portion of the tip portions projects away from the surface of the reflector, and wherein the second tip portion of the tip portions projects toward the surface of the reflector.

6. The base station antenna of claim 1, further comprising a conductive plate on the PCB and coupling the base portion of the metal radiator arm to the PCB, wherein the conductive plate and the base portion of the metal radiator arm respectively comprise different metals.

7. The base station antenna of claim 6, wherein the conductive plate comprises a copper plate.

8. The base station antenna of claim 1, wherein a widest dimension of each of the radiating elements does not exceed 68 millimeters in a direction parallel to the surface of the reflector.

9. The base station antenna of claim 1, wherein the vertical columns include a first, a second, a third, and a fourth consecutive vertical column, and wherein the first and third vertical columns are vertically interleaved relative to the second and fourth vertical columns.

10. The base station antenna of claim 9, wherein the first and second vertical columns are spaced apart from each other by at least 35 millimeters.

11. The base station antenna of claim 1, wherein the base portion of the metal radiator arm and the tip portion of the metal radiator arm are contiguous portions of a single continuous sheet of metal, and wherein opposing edge regions of the base portion are planar.

12. A base station antenna comprising a plurality of vertically staggered vertical columns of radiating elements configured to transmit radio frequency (RF) signals of a frequency band, and having curved metal radiator arms comprising tip portions facing respective central axes of the radiating elements, wherein, each of the radiating elements comprises a printed circuit board (PCB), wherein a base portion of the metal radiator arm of each of the radiating elements is on the PCB, and wherein the tip portion of the metal radiator arm of each of the radiating elements protrudes from a surface of the PCB.

13. The base station antenna of claim 12, wherein consecutive ones of the vertical columns are spaced apart from each other by at least 30 millimeters.

14. The base station antenna of claim 12, wherein first and second ones of the tip portions protrude in opposite directions, respectively.

15. The base station antenna of claim 14, further comprising a reflector, wherein the radiating elements are on a surface of the reflector, and wherein each of the opposite directions is not parallel to the surface of the reflector.

16. A base station antenna comprising: a reflector; and first and second vertical columns of radiating elements on a surface of the reflector and configured to transmit radio frequency (RF) signals of a frequency band, wherein each of the radiating elements comprises a printed circuit board (PCB) parallel to the surface of the reflector, wherein a first metal dipole arm of a first radiating element of the first vertical column comprises a first tip portion protruding away from the surface of the reflector, the first metal dipole arm comprising a first base portion extending on a surface of the PCB, and wherein a second metal dipole arm of a second radiating element of the second vertical column comprises a second tip portion protruding toward the surface of the reflector, the second metal dipole arm comprising a second base portion extending on the surface of the PCB.

17. The base station antenna of claim 16, wherein a third metal dipole arm of the first radiating element comprises a third tip portion protruding toward the surface of the reflector.

18. The base station antenna of claim 16, further comprising third and fourth vertical columns of radiating elements on the surface of the reflector and configured to transmit the RF signals of the frequency band, wherein the first, second, third, and fourth vertical columns are consecutive vertical columns, wherein the first and third vertical columns are vertically staggered with respect to the second and fourth vertical columns, and wherein the second tip portion is closer to the first tip portion than any other tip portion of the first vertical column.

19. The base station antenna of claim 18, wherein a shortest distance between the first vertical column and the second vertical column is longer than a length of the first tip portion.

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