Base station antenna unit and method for installing a base station antenna unit

Abstract

Multi-band base station antenna units include a first base station antenna having a first housing, a first radome extending forward from the first housing, a first vertically disposed linear array of low-band radiating elements mounted at a rear of the first radome, and a second vertically disposed linear array of mid-band radiating elements mounted at the rear of the first radome. The base station antenna units also include a second base station antenna having a second housing, a second radome extending forward from the second housing, and a third array of high-band radiating elements mounted at a rear of the second radome. The first base station antenna and the second base station antenna are mounted in a vertically stacked arrangement and are configured to be mounted as a single structure.

Description

[0001] This application is a divisional application of the application patent application with the application date of January 19, 2018, the application number of 201880002021.3, and the invention name of "Base station antenna unit and method for installing base station antenna unit".

[0002] Cross Reference to Related Applications

[0003] This application claims priority under 35 U.S.C. § 119 to U.S. Provisional Patent Application Serial No. 62 / 449,655, filed January 24, 2017, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0004] The present invention relates generally to radio communications, and more specifically to base station antennas that support communications in multiple frequency bands. BACKGROUND

[0005] Cellular communication systems are well known in the art. In a typical cellular communication system, a geographic region is divided into a series of zones called "cells," and each cell is served by one or more base stations. A base station can include baseband equipment, radios, and antennas that are configured to provide bidirectional radio frequency ("RF") communication with mobile subscribers that are geographically located within the cell. A common cellular communication system network plan involves a base station that serves a cell using three base station antennas, with each base station antenna serving a 120-degree "sector" of the cell in an azimuthal plane. The base station antennas are typically mounted on a tower or other raised structure, and the radiation pattern ("antenna beam") generated by each base station antenna points outward to serve the corresponding sector. Typically, the base station antennas are implemented as phased arrays of radiating elements that are arranged in one or more vertical columns. In this context, "vertical" refers to a direction that is perpendicular with respect to a plane defined by the horizon.

[0006] As the demand for cellular communication systems grows to support increased capacity and provide enhanced capabilities, various new cellular services have been introduced. These new services typically operate in different frequency bands than existing services to avoid interference. When a new service is introduced, the existing "legacy" services must typically be maintained to support legacy mobile devices. Therefore, as new services are introduced, either new cellular base stations must be deployed or existing cellular base stations must be upgraded to support the new services in the new frequency bands. To reduce cost and the total number of base station antennas deployed, base station antennas are now available that include at least two different arrays of radiating elements, with each array of radiating elements supporting a different type of cellular service in a different frequency band. Such antennas are commonly referred to as multi-band antennas. SUMMARY

[0007] According to embodiments of the present application, a base station antenna unit is provided that includes a first base station antenna having (1) a first housing, a first radome having a front surface located at a front of the first housing, a first vertically disposed linear array of low-band radiating elements mounted at a back of the front surface of the first radome, and a second vertically disposed linear array of mid-band radiating elements mounted at a back of the front surface of the first radome, and (2) a second base station antenna having a second housing separate from the first housing, a second radome having a front surface located at a front of the second housing, and a third array of high-band radiating elements mounted at a back of the front surface of the second radome, the second radome being separate from the first radome. The first base station antenna and the second base station antenna are mounted in a vertically stacked arrangement and are configured to be mounted as a single structure.

[0008] In some embodiments, a perimeter of a first horizontal cross-section through a central portion of the first base station antenna can be substantially the same as a perimeter of a second horizontal cross-section through a central portion of the second base station antenna.

[0009] In some embodiments, the third array of high-band radiating elements can be a planar array of radiating elements. The planar array can include at least four vertical columns of high-band radiating elements.

[0010] In some embodiments, a horizontal width of the first radome can be substantially the same as a horizontal width of the second radome.

[0011] In some embodiments, the second base station antenna is stacked above the first base station antenna.

[0012] In some embodiments, a height along a vertical direction of the second base station antenna can be less than 0.6 meters.

[0013] In some embodiments, a maximum horizontal depth of the first base station antenna can be less than a maximum horizontal depth of the second base station antenna.

[0014] In some embodiments, the second base station antenna can include a radome extending rearward having an end cap facing downward with a plurality of connectors mounted therein. At least some of the connectors can have respective longitudinal axes extending in a vertical direction.

[0015] In some embodiments, each high-band radiating element can have a mechanical downtilt, wherein the mechanical downtilt is provided by having a backplane of the third array of high-band radiating elements at least 1 degree from a vertical direction.

[0016] In some embodiments, the low-band radiating elements can be connected to at least one low-band phase shifter, the mid-band radiating elements are connected to at least one mid-band phase shifter, and the high-band radiating elements are connected to at least one high-band phase shifter, and wherein the at least one high-band phase shifter has a first preset electronic downtilt that exceeds a second preset downtilt of the at least one low-band phase shifter and exceeds a third preset downtilt of the at least one mid-band phase shifter.

[0017] According to further embodiments of the present application, a base station antenna unit is provided, the base station antenna unit comprising a first base station antenna and a second base station antenna, the first base station antenna comprising a first housing having a first bottom end cap, the second base station antenna comprising a second housing having a second bottom end cap. The second base station antenna is mounted in a stacked arrangement directly above the first base station antenna in a vertical direction. The second bottom end cap comprises a plurality of connectors mounted therein.

[0018] In some embodiments, the first base station antenna and the second base station antenna are configured to be installed as a single structure.

[0019] In some embodiments, at least some of the connectors have respective longitudinal axes extending in the vertical direction.

[0020] In some embodiments, a perimeter of a first horizontal cross-section through a central portion of the first base station antenna can be substantially the same as a perimeter of a second horizontal cross-section through a central portion of the second base station antenna.

[0021] In some embodiments, the first base station antenna comprises a first vertically disposed linear array of low-band radiating elements and a second vertically disposed linear array of mid-band radiating elements, and the second base station antenna comprises a planar array of high-band radiating elements.

[0022] In some embodiments, a lowermost portion of the second base station antenna is within four inches of an uppermost portion of the first base station antenna.

[0023] In some embodiments, a maximum horizontal depth of the first base station antenna is less than a maximum horizontal depth of the second base station antenna.

[0024] In some embodiments, the second base station antenna comprises a radome extending rearwardly, and the second bottom end cap is a downwardly facing end cap that is part of the radome and has the plurality of connectors mounted therein.

[0025] In some embodiments, the first base station antenna and the second base station antenna share a common radome.

[0026] According to yet other embodiments of the present application, a base station antenna is provided that includes a backplane, a first vertically disposed linear array of low band radiating elements mounted on a front of the backplane, a second vertically disposed linear array of mid band radiating elements mounted on the front of the backplane, and a third two-dimensional array of high band radiating elements mounted on the front of the backplane. When the base station antenna is installed for use, an uppermost one of the high band radiating elements is mounted higher on the front of the backplane than an uppermost one of the low band radiating elements and an uppermost one of the mid band radiating elements.

[0027] In some embodiments, when the base station antenna is installed for use, the high band radiating elements are tilted downward from a plane parallel to a plane defined by the horizon.

[0028] In some embodiments, the base station antenna can further include a fourth vertically disposed linear array of mid band radiating elements mounted on the front of the backplane, wherein the first vertically disposed linear array of low band radiating elements is positioned between the second and fourth vertically disposed linear arrays of mid band radiating elements.

[0029] In some embodiments, the uppermost low band radiating element is mounted higher on the backplane than the uppermost mid band radiating element.

[0030] In some embodiments, each low band radiating element is a cross-polarized radiating element having a vertically oriented dipole and a horizontally oriented dipole.

[0031] In some embodiments, at least one of the low band radiating elements is mounted within a perimeter of the third two-dimensional array of high band radiating elements. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1A is a perspective view of a conventional multi-band base station antenna.

[0033] Figure 1B is Figure 1A is a schematic front view of the conventional multi-band base station antenna of

[0034] Figure 2A is a schematic side view of a multi-band base station antenna unit including two co-mounted base station antennas according to certain embodiments of the present application.

[0035] Figure 2B is Figure 2A is a schematic front view of the multi-band base station antenna unit of

[0036] Figure 2C is a front view of a multi-band base station antenna unit of Figure 2A wherein the radomes of each base station antenna are in place.

[0037] Figure 3A and 3B are side and front views of two low-band radiating elements included in a base station antenna unit of Figures 2A-2C

[0038] Figure 3C and 3D are front and side views of two mid-band radiating elements included in a base station antenna unit of Figures 2A-2C

[0039] Figures 4A-4C are schematic views of several example structural attachments that can be used to connect two base station antennas of Figures 2A-2C to form a base station antenna unit.

[0040] Figure 5 is a perspective view of a base station antenna unit including a first base station antenna and a second base station antenna sharing a common radome according to an embodiment of the invention.

[0041] Figures 6A-6B are schematic perspective and front views of a tri-band base station antenna including multiple linear arrays of radiating elements and a planar array of radiating elements according to a further embodiment of the invention.

[0042] Figures 6C-6D are schematic front views of two additional tri-band base station antennas that are modified versions of the tri-band base station antenna of Figures 6A-6B according to a further embodiment of the invention. DETAILED DESCRIPTION

[0043] ​​Now, many prior art base station antennas include multiple vertical columns ("arrays") of radiating elements in order to support several different types of cellular service. A very common base station antenna configuration includes a first vertical linear array of radiating elements that transmit and receive signals of a first frequency band (here, a "low band") and one or more additional vertical linear arrays of radiating elements that transmit and receive signals of a second frequency band (here, a "mid band") that is higher in frequency than the first frequency band. These antennas are referred to as "dual band" antennas because they support service in two different frequency bands using two different sets of radiating elements. Typically, the first frequency band includes one or more specific frequency bands below about 1.0 GHz and the second frequency band includes one or more specific frequency bands in the range of 1.0-3.0 GHz (and typically between about 1.6-2.7 GHz). The specific frequency bands can correspond to specific types of cellular service, such as, for example, Global System for Mobile Communications ("GSM") service, Universal Mobile Telecommunications System ("UTMS") service, Long Term Evolution ("LTE") service, CDMA service, etc.

[0044] Figure 1A and 1B A typical conventional multi-band base station antenna 100 is illustrated. Specifically, Figure 1A is a perspective view of the conventional multi-band base station antenna 100, and Figure 1B is a schematic front view of the multi-band base station antenna 100 with a radome removed from the base station antenna to schematically illustrate the linear arrays of radiating elements included in the antenna 100.

[0045] As Figure 1A shown, the conventional multi-band base station antenna 100 includes a housing 140 and a radome 160 mounted on a front portion of the housing 140. The housing 140 can include a tray 142 that extends around the sides and back of the antenna 100 as well as a bottom end cap 146 and a top end cap 148. The tray 142, end caps 146, 148, and radome 160 protect the antenna 100. The radome 160 and tray 142 can be formed of, for example, extruded plastic and can be multiple pieces or implemented as a monolithic structure. In other embodiments, the tray 142 can be made of metal and can act as an additional reflector to improve the front-to-back ratio of the antenna 100. A mounting bracket 170 can extend through a rear portion of the tray 142, which can be used to mount the base station antenna 100 to another structure, such as, for example, an antenna tower (not shown). A plurality of connectors 150 can extend through respective openings in the bottom end cap 146. Cables (not shown) can be connected to the connectors 150 to transfer signals between the base station antenna 100 and a plurality of radios (not shown).

[0046] Reference is now made to Figure 1BAs can be seen, the base station antenna includes a first vertical array 120 of low-band radiating elements 122, a second vertical array 130-1 of mid-band radiating elements 132, and a third vertical array 130-2 of mid-band radiating elements 132. It should be noted that, herein, when multiple identical components are provided, the components can be assigned two-part designations, and the components can be referred to individually by the full designation of the components (e.g., vertical array 130-2) and collectively by the first part of the designation of the components (e.g., vertical array 130). Each of the three vertical arrays 120, 130-1, 130-2 can be mounted on the reflector 110. The radiating elements 122 in the first vertical array 120 can be fed by a first corporate feed network (not shown) that splits a low-band RF signal to be transmitted into a plurality of sub-components. Each sub-component can be fed to one of the radiating elements 122 or to a sub-array that includes a plurality of radiating elements 122. One or more phase shifters (not shown) can be included in the corporate feed network. The phase shifters can apply different phase shifts to respective ones of the sub-components of the low-band RF signal to apply a phase taper to the sub-components that can be used to control an azimuth beamwidth of an antenna beam formed by the first vertical array 120 and / or to adjust an elevation of the antenna beam formed by the first vertical array 120. In example embodiments, the antenna beam formed by the first vertical array 120 can have an azimuth beamwidth of about 125 degrees and an elevation beamwidth of about 10-30 degrees, for example. The phase shifters and the corporate feed network can be mounted within the housing 140.

[0047] In some embodiments, the second vertical array 130-1 and the third vertical array 130-2 can be fed by a second corporate feed network (not shown) that splits the mid-band RF signals to be transmitted into a plurality of sub-components. Each sub-component can be fed to one of the radiating elements 132 or to a sub-array comprising a plurality of radiating elements 132. One or more phase shifters (not shown) can be included in the corporate feed network. The phase shifters can apply different phase shifts to respective ones of the sub-components of the mid-band RF signals to apply a phase taper to the sub-components that can be used to control an elevation beamwidth of an antenna beam formed by the second vertical array 130-1 and the third vertical array 130-2 and / or to adjust an elevation of an antenna beam formed by the second vertical array 130-1 and the third vertical array 130-2. The antenna beam formed by the second vertical array 130-1 and the third vertical array 130-2 can have, for example, an azimuth beamwidth of about 125 degrees and an elevation beamwidth of about 10-30 degrees. In other embodiments, the second vertical array 130-1 and the third vertical array 130-2 can be fed by respective second and third corporate feed networks (not shown). For example, the second vertical array 130-1 and the third vertical array 130-2 can be connected to respective radios that communicate in different sub-bands of the second frequency range. In such embodiments, the second vertical array 130-1 and the third vertical array 130-2 can generate independent antenna beams that overlap in a coverage area but are frequency separated.

[0048] Many mobile operators are considering deploying new services in a third frequency band that is higher in frequency than the first and second frequency bands discussed above. For example, many mobile operators, particularly in Europe and / or the United States, are considering using a frequency band around 3.5 GHz to support new services. Services can also be supported in the unlicensed 5 GHz spectrum, for example. These frequency bands can be used to support, for example, Long Term Evolution (“LTE”) Time Division Duplex (“TDD”) services or other 5G technologies. To avoid increasing the antenna count at the cellular base station, it can be desirable to support services in the third frequency band in the same antenna structure used to support services in the first and second frequency bands. Reducing the number of antennas can have a number of advantages, including reducing installation costs, reducing the number of installation supports needed on the antenna tower, reducing the overall weight of the antennas, and a more aesthetic appearance, and can also be required in some cases to comply with local regulations and / or zoning regulations.

[0049] Unfortunately, increasing the number of frequency bands supported by a base station antenna can tend to require larger and more complex antenna structures. Moreover, the more frequency bands a base station antenna supports, the greater the likelihood of interference between signals transmitted in different frequency bands. For example, integrating radiating elements for 3.5 GHz or 5 GHz frequency bands into a conventional dual-band base station antenna, such as the base station antenna 100 that supports services in the first and second frequency bands described above, would require compromising some performance metrics for the lower frequency bands. Thus, despite the aforementioned drawbacks of using separate units, many operators are considering using separate antenna structures to support 3.5 GHz or 5 GHz frequency bands.

[0050] Base station antennas typically have a number of vertical lengths. In particular, the elevation beamwidth of a vertical array of radiating elements included on a base station antenna is a function of (1) the frequency band and (2) the spacing between the uppermost and lowermost radiating elements in the vertical array. Depending on the size and geographic environment of a cell, as well as various other parameters, an operator can need base station antennas with different elevation beamwidths. For example, in some cases, it can be desirable to have a small elevation beamwidth (e.g., 10-15 degrees) in order to increase antenna gain and / or reduce spillover of the antenna beam to neighboring cells (as such spillover appears as interference to neighboring cells). This requires a relatively long base station antenna with a large spacing between the uppermost and lowermost radiating elements in order to narrow the elevation beamwidth of the antenna beam. In other cases, a larger elevation beamwidth is acceptable, allowing a shorter base station antenna with fewer radiating elements in the vertical array to be used. Typical heights for base station antennas are 1.5 meters (or 4 feet), 2.0 meters (or 6 feet), and 2.5 meters (or 8 feet). While the number of base station antennas deployed at a base station is an important parameter (e.g., in order to comply with local zoning regulations and / or because installation fees are typically charged on a per-antenna basis), the height of each base station antenna is typically less of a concern.

[0051] According to embodiments of the present invention, a composite base station antenna unit is provided in which a first base station antenna and a second base station antenna are mounted together in a vertically stacked arrangement such that the composite base station antenna unit has the appearance of a single base station antenna. The first base station antenna can comprise a conventional dual-band base station antenna including one or more low-band vertical arrays of radiating elements that communicate in a first frequency band (e.g., some or all of the 696-960 MHz band), and one or more mid-band vertical arrays of radiating elements that communicate in a second frequency band (e.g., the 2.5-2.7 GHz band). The height of the first base station antenna (i.e., the length of the antenna in the vertical direction perpendicular to the plane defined by the horizon when the antenna is mounted for use) can be, for example, in the range of about 1.0 meters to about 2.0 meters. The second base station antenna can comprise a planar array of radiating elements that communicate in a third frequency band (e.g., the 3.5 GHz or 5 GHz band). In some embodiments, the height of the second base station antenna can be, for example, in the range of about 0.5 meters or less. Thus, a base station antenna unit according to embodiments of the present invention can no longer be a conventional 2.5 meter base station antenna.

[0052] The first base station antenna and the second base station antenna can be mounted as a single unit, and can appear as a single base station antenna from at least a distance. For example, the first base station antenna and the second base station antenna can be vertically aligned, and can have substantially the same width. In some embodiments, the two antennas can be in direct contact, or nearly in direct contact, such that they appear as a single antenna when viewed from the front. The two antennas can be secured to each other or to a common mounting structure that connects the two antennas to form a single base station antenna unit. In some embodiments, the single base station antenna unit including the two base station antennas can be mounted to a tower or other raised structure using conventional base station antenna mounting hardware. By combining the two base station antennas into a single base station antenna unit, it can appear that fewer base station antennas are mounted on the cell tower, which can be more aesthetically pleasing. The base station antenna unit according to embodiments of the present invention can also be less expensive and easier to install on a cell tower and require less mounting hardware than providing two separate base station antennas with comparable functionality.

[0053] In some embodiments, the first base station antenna can include a first vertical array of low-band radiating elements, and a second vertical array and a third vertical array of mid-band radiating elements. The first vertical array can be positioned between the second vertical array and the third vertical array. The second base station antenna can include a fourth array of high-band radiating elements. The fourth array can include a plurality of columns of high-band radiating elements that can be arranged in a planar array. In some embodiments, the fourth array can include at least three vertical columns of high-band radiating elements and at least three rows of high-band radiating elements.

[0054] In some embodiments, the first base station antenna and the second base station antenna can share a common radome. Using such a common radome can enhance the appearance of the two base station antennas as a single antenna. In further embodiments, the first base station antenna and the second base station antenna can be replaced with a single base station antenna that includes all four of the first array, the second array, the third array, and the fourth array of radiating elements described above. The fourth array can be mounted above the first vertical array, the second vertical array, and the third vertical array. The first vertical array can be mounted between the second vertical array and the third vertical array.

[0055] Embodiments of the present application will now be discussed in further detail with reference to the drawings, in which example embodiments of the present application are illustrated.

[0056] Figures 2A-2C and 3A-3D illustrate a base station antenna unit 200 comprising two co-mounted base station antennas 300, 400 according to certain embodiments of the present application. Specifically, Figure 2A is a schematic side view of a multi-band base station antenna unit 200, Figure 2B is a schematic front view of a multi-band base station antenna unit 200 with the radomes of each base station antenna 300, 400 removed, and Figure 2C is a front view of a multi-band base station antenna unit 200 with the radomes of each base station antenna 300, 400 in place. Figure 3A and 3B are a side view and a front view, respectively, of two low-band radiating elements included in the base station antenna 300. Figure 3C and 3D are a front view and a side view, respectively, of two mid-band radiating elements included in the base station antenna unit 300.

[0057] Referring to Figure 2A and 2C the base station antenna unit 200 comprises a first base station antenna 300 and a second base station antenna 400. The second base station antenna 400 is mounted on top of the first base station antenna 300. The first base station antenna 300 and the second base station antenna 400 can appear to be a single base station antenna. The second base station antenna 400 can be referred to herein as a “high-band box top” because the second base station antenna 400 can be configured to communicate in a high-band and can be mounted on top of the first base station antenna 300.

[0058] Referring to Figure 2B, the first base station antenna 300 includes three vertically oriented linear arrays of radiating elements, namely, a low-band array 320 including a plurality of low-band radiating elements 322, and a first mid-band array 330-1 and a second mid-band array 330-2, each including a plurality of mid-band radiating elements 332. The vertical arrays 320, 330-1, 330-2 can be similar to the vertical arrays 120, 130-1, 130-2 of the base station antenna 100 discussed above. It should be appreciated that any suitable number of radiating elements 322, 332 can be included in the vertical arrays 320, 330-1, 330-2. The radiating elements 322, 332 are mounted on a backplate 310. The backplate 310 can include a unitary structure or can include multiple structures attached together. The backplate 310 can include, for example, a reflector that serves as a ground plane for the radiating elements 322, 332.

[0059] Now refer to Figure 3A and 3B , it can be seen that each low-band radiating element 322 may include a rod 324 and a radiator 326. Each rod 324 may include one or more printed circuit boards. The radiator 326 may include, for example, a dipole radiator. In the depicted embodiment, the base station antenna 300 is a dual-polarized antenna, and therefore each radiator 326 includes a cross-dipole structure. Each radiator 326 may be arranged in a plane that is substantially perpendicular to the longitudinal axis of the corresponding rod 324 of the radiating element 322. In the depicted embodiment, the low-band radiating elements 322 are mounted in pairs on corresponding feed boards 328, which provide sub-components of the RF signal to be transmitted to the corresponding radiating element 322. The support member 325 may help to hold the radiator 326 in place. It should be recognized that although Figures 3A-3B One example low-band radiating element 322 is illustrated that may be used in a base station antenna unit according to embodiments of the present invention, but any suitable low-band radiating element may be used.

[0060] like Figures 3C-3D As shown, each mid-band radiating element 332 may include a rod 334 and a radiator 336. Each rod 334 may include one or more printed circuit boards. Radiators 336 may include, for example, dipole or patch radiators. In the depicted embodiment, each mid-band radiator 336 comprises a cross-dipole radiator 336 formed on a printed circuit board. Each radiator 336 may be arranged in a plane substantially perpendicular to the longitudinal axis of the corresponding rod 334 of the radiating element 332. In the depicted embodiment, the mid-band radiating elements 332 are mounted in pairs on corresponding feed boards 338, which provide sub-components of the RF signal to be transmitted to the corresponding radiating element 332. Directors 337 may be mounted above the radiating elements 332 to help narrow the beamwidth of the radiating elements 332.

[0061] Reference again Figures 2A-2C The first base station antenna 300 further includes a housing 340 and a radome 360. The housing 340 may include a tray 342 that extends around the sides and rear of the antenna 300, as well as a bottom end cap 346 and a top end cap 348. The tray 342, end caps 346 and 348, and the radome 360 ​​protect the antenna 300. The radome 360 ​​and the tray 342 may be formed, for example, from extruded plastic and may be multiple components or implemented as a single piece. In other embodiments, the tray 342 may be made of metal. A mounting bracket 370 may extend through the rear of the tray 342.

[0062] The back panel 310 may be mounted on or in the housing 340. The radiating elements 322, 332 of the first to third vertical arrays 320, 330-1, 330-2 may extend forward from the back panel 310. The radome 360 ​​may be attached to the tray 342 and may extend forward from the tray 342 to cover and protect the radiating elements 322, 332.

[0063] A plurality of connectors 350 can be mounted within the opening in the bottom end cap 346. Each connector 350 can have a longitudinal axis. When the base station antenna 300 is mounted for use, the longitudinal axes of at least some of the connectors 350 can extend substantially in a vertical direction.

[0064] A plurality of circuit elements and other structures may be mounted within the housing 340. These circuit elements and other structures may include, for example, phase shifters for one or more of the first to third vertical arrays 320, 330-1, and 330-2, remote electronic tilt (RET) actuators for mechanically adjusting the phase shifters, one or more controllers, filters such as duplexers and / or diplexers, cable connections, RF transmission lines, and the like.

[0065] The second base station antenna 400 includes a two-dimensional planar array 420 of high-band radiating elements 422. The planar array 420 may include at least two columns and two rows of high-band radiating elements 422. In the depicted embodiment, the planar array 420 includes four columns and six rows of high-band radiating elements 422, for a total of twenty-four high-band radiating elements 422. The high-band radiating elements 422 are mounted on a backplate 410. The backplate 410 may include a unitary structure or may include multiple structures attached together. The backplate 410 may include, for example, a reflector that serves as a ground plane for the high-band radiating elements 422.

[0066] In some embodiments, each high-band radiating element 422 can comprise a dipole or patch radiator. If the base station antenna 400 is a dual-polarized antenna, each high-band radiating element 422 can comprise, for example, a cross-dipole structure.

[0067] The second base station antenna 400 also includes a housing 440 and a radome 460. The backplane 410 can be mounted on or in the housing 440. The high-band radiating elements 422 of the fourth planar array 420 can extend forward from the backplane 410. The radome 460 can be attached to the housing 440 and can extend forward from the housing 440 to cover and protect the high-band radiating elements 422.

[0068] The housing 440 can include a tray 442 that extends around the sides and back of the antenna 400 as well as a bottom end cap 446 and a top end cap 448. The radome 460 and the tray 442 can be formed from, for example, extruded plastic and can be formed from multiple parts or implemented as a monolithic structure. In other embodiments, the tray 442 can be made of metal. An upper portion of the housing 440 can extend further back than a lower portion of the housing 440 to define a lip 441. A base plate 443 can form a bottom surface of the lip 441. A plurality of connectors 450 can be mounted within openings in the base plate 443. Each connector 450 can have a longitudinal axis. The longitudinal axes of at least some of the connectors 450 can extend substantially in a vertical direction. Since the bottom end cap 446 can not be accessible when the second base station antenna 400 is mounted on the first base station antenna 300, the lip 441 and the base plate 443 provide a convenient means for mounting the connectors 450 of the second base station antenna 400 in a location that is easily accessible.

[0069] In some embodiments, the high-band radiating elements 422 can be configured to operate in the 3.5 GHz band or the 5 GHz band, although embodiments of the application are not limited thereto. The planar array 420 of high-band radiating elements 422 can be configured to perform time-division duplex beamforming operations in which different antenna beams can be formed in different time slots to provide communication to different users or sets of users during each different time slot. The planar array 420 of high-band radiating elements 422 can be configured to generate a plurality of different antenna beams during any given time slot in order to provide highly directional coverage to selected portions of the coverage area during the given time slot.

[0070] As Figures 2A-2CAs shown, the second base station antenna 400 is mounted on top of the first base station antenna 300 to form the base station antenna unit 200. In an example embodiment, the lowermost portion of the second base station antenna 400 can be located, for example, within six inches, or within four inches, or within two inches of the uppermost portion of the first base station antenna 300. The front surface 462 of the radome 460 of the second base station antenna 400 can be substantially vertically aligned with the front surface 362 of the radome 360 ​​of the first base station antenna 300. Figure 2C As shown, the width W1 of the radome 360 ​​can be substantially the same as the width W2 of the second radome 460. The front surfaces 362, 462 of the first and second radomes 360, 460 can be curved. In some embodiments, the front surfaces 362, 462 can have substantially the same curvature.

[0071] An attachment mechanism 210 may be provided to attach the first base station antenna 300 to the second base station antenna 400. In some embodiments, the attachment mechanism 210 may be one or more supports extending upward from the first base station antenna 300, attached to, surrounding, and / or otherwise supporting the second base station antenna 400. In other embodiments, the attachment mechanism 210 may be one or more supports extending downward from the second base station antenna 400, attached to the first base station antenna 300. In still other embodiments, the attachment mechanism 210 may include a separate structure attached to both the first base station antenna 300 and the second base station antenna 400. A variety of other attachment mechanisms 210 will be apparent to those skilled in the art in light of the teachings of this disclosure, who will recognize that any suitable attachment mechanism 210 may be used.

[0072] The attachment mechanism 210 allows the first base station antenna 300 and the second base station antenna 400 to be mounted as a single structure (i.e., as a base station antenna unit 200). In some embodiments, the first base station antenna 300 may include a mounting bracket 370 or other attachment point / structure for mounting the base station antenna unit 200, for example, on an antenna tower. Thus, both base station antennas 300 and 400 can be installed in a single mounting location, thereby conserving space on the antenna tower. Furthermore, because both base station antennas 300 and 400 can be mounted as a single unit using a single set of mounting brackets 370 or the like, both base station antennas 300 and 400 can be installed with substantially the same amount of effort as would be required to install a single conventional base station antenna.

[0073] Another advantage of the high-band over-the-top design of the base station antenna unit 200 is that coupling between radiating elements of different frequency bands in a multi-band base station antenna tends to be more problematic when the radiating elements are close to each other in the azimuth (horizontal) plane that is opposite the elevation (vertical) plane. Here, the first base station antenna 300 can include a conventional base station antenna that includes, for example, a vertical array of low-band radiating elements disposed between vertical arrays of mid-band radiating elements. In a base station antenna having a width that is suitably narrow (e.g., a width of 350 mm or less), sufficient isolation between the low-band radiating elements and the mid-band radiating elements can be readily achieved using conventional techniques. If the columns of high-band radiating elements 422 are interspersed between the low-band vertical array 320 and the mid-band vertical arrays 330-1, 330-2, it can be very difficult to minimize the impact of the high-band radiating elements 422 on the low-band radiating elements 322 and / or the mid-band radiating elements 332, even with decoupling structures. However, by mounting the high-band radiating elements 422 above the low-band vertical array 320 and the mid-band vertical arrays 330-1, 330-2, it can be considered that the amount of coupling between the high-band radiating elements 422 and the low-band radiating elements 322 and / or the mid-band radiating elements 332 can be kept relatively low, such that all of the arrays in the low-band array 320, the mid-band arrays 330, and the high-band array 420 can exhibit good performance.

[0074] A typical RVV-type base station antenna that includes one low-band (R-band) linear array and two mid-band (V-band) linear arrays has a width of 350 mm or less. This width can accommodate a high-band array 420 having at least four columns or high-band radiating elements 422, and assuming a spacing of 0.65λ between adjacent high-band radiating elements 422, it can be possible to accommodate a high-band array 420 of up to six columns or high-band radiating elements 422 in a 3.5 GHz band (i.e., 8.5 cm wavelength). It can be recognized that a high-band over-the-top antenna that includes two low-band (R-band) linear arrays and two mid-band (V-band) linear arrays can also be provided that is configured to be mounted on top of an RRV base station antenna. A high-band over-the-top antenna designed to be mounted on top of an RRV base station antenna can include an even greater number of columns in the high-band array.

[0075] A base station antenna unit 200 comprising two separate base station antennas 300, 400 will appear as a single base station antenna from at least some distances. This is possible because the first base station antenna 300 and the second base station antenna 400 can have similar or even identical front profiles, and can be installed close to one another. Indeed, in some embodiments, the bottom of the second base station antenna 400 can directly contact the top of the first base station antenna 300. In some embodiments, the second base station antenna 400 can have a lip or "cowling" 441 that extends rearward, and thus the maximum depth of the second base station antenna 400 can exceed that of the first base station antenna 300. As noted above, this can facilitate the vertical installation of the connectors 450 of the second base station antenna 400 in the base plate 443, so that the cables feeding the second base station antenna 400 can be connected to the lower surface of the antenna 400, which helps to prevent water / moisture ingress. However, because the cowling 441 faces rearward, it should not substantially disrupt the appearance of the two base station antennas 300, 400 as a single antenna.

[0076] A wide variety of attachment structures can be used to attach the first base station antenna 300 and the second base station antenna 400 to one another to form the base station antenna unit 200. For example, as shown in FIG. 5, in some embodiments a plurality of upwardly extending support arms 500 can be installed via screws, bolts, rivets, or a variety of other attachment mechanisms in the upper portion of the housing 340 of the first base station antenna 300. The upper portions of these support arms 500 can be attached to the housing 440 of the second base station antenna 400 to attach the two base station antennas 300, 400 together to form the base station antenna unit 200. As shown in FIG. 6, in another embodiment an external housing 510 can be provided that has a front surface that does not block RF energy, and both the first base station antenna 300 and the second base station antenna 400 can be installed within this housing 510. The housing 510 can include openings along its rear surface (not visible in the figure) that allow the mounting brackets 370 of the first base station antenna 300 to extend outside of the housing 510, so that the mounting brackets 370 can be used to mount the base station antenna unit 200 on an antenna tower or other structure. As shown in FIG. 7, in yet other embodiments a composite radome 520 can be provided that acts as a radome for both the first base station antenna 300 and the second base station antenna 400 (eliminating the need for radomes 360, 460), and that can be used as at least part of a structured mechanism for attaching the first base station antenna 300 and the second base station antenna 400 to one another. In such embodiments, additional structured mechanisms can also be provided, such as the support arms 500 described above. Figure 4A Figure 4B Figure 4C

[0077] ​​​It should be appreciated that many other attachment structures can be used. The attachment structure should provide mechanical integrity and ensure directional stability of the second base station antenna 400 (assuming the mounting bracket 370 on the first base station antenna 300 is used to mount the base station antenna unit 200 to a tower or other structure). The attachment structure should also not have a significant impact on the RF performance of the first base station antenna 300 or the second base station antenna 400, although it is noted that in some cases, an attachment structure can be provided that is designed to improve the RF performance of one or both of the base station antennas 300, 400, e.g., by attenuating undesired side lobes in its antenna pattern.

[0078] The base station antenna unit 200 can be field deployable in that the second base station antenna 400 can be designed to attach to a conventional base station antenna in order to form the base station antenna unit 200.

[0079] In some embodiments, the high-band array 420 can be designed to have a different coverage area than the low-band array 320 and the mid-band arrays 330-1, 330-2. For example, in some cases, the high-band array 420 can be designed to cover only a portion of a cell that is closer to a mounting structure (e.g., an antenna tower) on which the base station antenna unit 200 is mounted. The reason that the base station antenna unit 200 can have such a design is that, for example, the free space loss at 3.5 GHz or 5 GHz will be higher than the free space loss at the frequencies of the low-band and mid-band, making it potentially more difficult to achieve coverage of the entire cell.

[0080] Because the high-band array 420 can have a reduced coverage area, it can be advantageous to“preset” the high-band array 420 to have a certain amount of downtilt (i.e., tilt at an angle below the horizon in the elevation plane). Such downtilt can be mechanical downtilt or electrical downtilt. As is known to those skilled in the art, mechanical downtilt refers to physically pointing the radiating elements of the array downward from a plane that is parallel to the plane defined by the horizon. Such downtilt is often used so that the main lobe of the antenna beam formed by the array will be pointed toward the ground at a distance from the base station antenna. This technique can be used to increase the antenna gain within the coverage area of the base station antenna and / or to reduce the extent to which the antenna beam extends into neighboring cells.

[0081] Electrical downtilt refers to downtilt achieved by adjusting the phase and / or amplitude of a subcomponent of the RF signal transmitted or received by the array's radiating elements. Electrically downtilting a phased array antenna is generally preferred over using mechanical downtilt, both because the antenna pattern achieved using electrical downtilt is different and generally preferred from that formed by mechanically downtilting a phased array antenna, and because electrical downtilt is typically achieved from a remote location using a "remote electrical downtilt" capability by sending a control signal that adjusts settings on phase shifters included along the RF path in the antenna to achieve the electronic downtilt.

[0082] In some embodiments, each high-band radiating element 422 can have a mechanical downtilt, such as, for example, a mechanical downtilt of 1-5 degrees. Since the total height of the second base station antenna 400 can be quite small (e.g., 0.5 meters or less), this mechanical downtilt can be achieved by physically tilting the backplate 410 away from the vertical plane within the radome 460. This is not possible in taller antennas (e.g., 1.5 to 2.5 meter antennas) because the mechanical downtilt may require increasing the depth of the antenna. In addition, the high-band radiating element 422 can be significantly shorter than the low-band radiating element 322 and the mid-band radiating element 332, and therefore there may be room in the second base station antenna 400 for a tilted backplate 410.

[0083] According to embodiments of the present invention, the base station antenna unit and base station antenna described herein can be designed so that the phase shifters included in the antenna are preset to apply a predetermined amount of electrical downtilt to the high-frequency array. For example, in some embodiments, the phase shifters can be set so that the high-band array has a preset downtilt between 2 and 6 degrees. As known to those skilled in the art, when electronic downtilt is applied to a phased array antenna, the antenna pattern of the phased array antenna may be distorted, and the amount of distortion tends to increase with the increase in the downtilt amount. For example, when the electrical downtilt exceeds a certain amount, grating lobes may appear. The preset downtilt means that the phase shifters are set so that the highest elevation angle at which the high-band array 420 can be set is below the horizon (e.g., 2 to 6 degrees). Then, using the phase shifters included in the common feed network for the high-band array 420, the downtilt amount can be increased by some additional amount. In other embodiments, the radiating elements 422 of the high-band array 420 can have a preset amount of mechanical downtilt (e.g., 2-6 degrees) and then the electrical downtilt can be used to further adjust the elevation pointing angle of the high-band array 420.

[0084] In some embodiments, the high-band array 420 may be configured to have a greater amount of preset electrical downtilt than the low-band array 320 and / or the mid-band array 330 .

[0085] While the base station antenna unit 200 includes two completely separate base station antennas 300, 400 that are mounted together as a single antenna, it should be appreciated that in other embodiments some components can be shared between the two antennas. For example, Figure 5 is a perspective view of a base station antenna unit 550 that includes a first base station antenna and a second base station antenna that share a common radome 560. The use of a common radome can enhance the appearance of the first base station antenna and the second base station antenna as a single antenna.

[0086] While the above embodiments of the present invention are directed to base station antenna units that include a first base station antenna and a second base station antenna, it will be appreciated under the teachings of the present disclosure that in other embodiments a single tri-band base station antenna that includes an array of radiating elements that supports all three low-band, mid-band, and high-band frequency bands in a single housing can be provided. Such a base station antenna can have an array arranged in the same manner as the above-described base station antenna unit 200, but it can also be possible to further optimize the positions of the array to reduce interference.

[0087] Figures 6A-6D several example tri-band base station antennas 600, 601, 602 having such a design are schematically illustrated in accordance with embodiments of the present invention. In particular, Figure 6A is a schematic perspective view of a tri-band base station antenna 600, and Figure 6B is a schematic front view of the base station antenna 600 with the radome of the base station antenna 600 removed. Figures 6C-6D are schematic front views of tri-band base station antennas 601, 602 that are modified versions of the tri-band base station antenna 600 with the radomes removed.

[0088] As can be seen from Figures 6A-6B the tri-band base station antenna 600 includes three vertically oriented linear arrays of radiating elements, namely a low-band array 620 that includes a plurality of low-band radiating elements 622 and a first mid-band array 630-1 and a second mid-band array 630-2 that each include a plurality of mid-band radiating elements 632. The low-band radiating elements 622 and the mid-band radiating elements 632 can be identical to the above-described corresponding low-band radiating elements 322 and mid-band radiating elements 332, and further description thereof will therefore be omitted.

[0089] The tri-band base station antenna 600 further includes a two-dimensional planar array 720 of high-band radiating elements 722. The planar array 720 can include at least two columns and two rows of high-band radiating elements 722, and can be identical to the above-described planar array 420. The high-band radiating elements 722 can be identical to the above-described high-band radiating elements 422, and further description thereof will therefore be omitted.

[0090] Radiating elements 622, 632, 722 can be mounted on a common backplane 610. Backplane 610 can comprise a unitary structure or can comprise multiple structures that are attached together. Backplane 610 can include a reflector that serves as a ground plane for radiating elements 622, 632, 722, for example. As Figure 6A shown, tri-band base station antenna 600 can also include a housing 640 and a radome 660. Backplane 610 can be mounted on or in housing 640. Radiating elements 622, 632, 722 can extend forward from backplane 610. Radome 660 can be attached to housing 640 and can extend forward from housing 640 to cover and protect radiating elements 622, 632, 722. Housing 640 can include a tray 642, a bottom end cap 646, and a top end cap 648. Radome 660 can be attached to tray 642. A plurality of connectors 650 can be mounted within openings in bottom end cap 646. Note that the radome 441 included in second base station antenna 400 discussed above is not needed in antennas 600, 601, 602, because connectors 750 for high-band array 720 can be mounted in bottom end cap 646, and cables or transmission lines can continue through housing 640 to the corporate feed network for high-band array 720. Base station antennas 601 and 602 can have the same housing and radome design as base station antenna 600, and thus can look the same as base station antenna 600 in perspective view. Figure 6A

[0091] Base station antennas 600, 601, 602 differ from each other in the relative positions of radiating elements 622, 632, 722. For example, as Figure 6B shown, base station antenna 600 is designed to position radiating elements 622, 632, 722 in the same positions as corresponding radiating elements 322, 332, 422 of base station antenna unit 200 in which it is mounted. Thus, the main difference between base station antenna unit 200 and base station antenna 600 is that base station antenna 600 includes a single housing 640 and a single radome 660, whereas base station antenna unit 200 includes two housings 340, 440 and two radomes 460, 660. Also as Figure 6B shown, because base station antenna 600 integrates arrays for all three low-band, mid-band, and high-band frequencies into a single antenna, connectors for transmitting RF signals in each of the low-band, mid-band, and high-band frequencies can be integrated into bottom end cap 646 of housing 640, eliminating any need for radome 441 provided in base station antenna unit 200 discussed above. The same is true for base station antennas 601 and 602, as can be seen from Figure 6C and 6D ​The support arm 500 (or other attachment structure) included in the base station antenna unit 200 can also be omitted in the base station antenna 600.

[0092] Next go to Figure 6C , it can be seen that base station antenna 601 is similar to base station antenna 600, except that mid-band linear arrays 630-1 and 630-2 are moved downward on backplate 610. Typically, the vertical height of mid-band linear arrays 630-1 and 630-2 is less than the vertical height of low-band linear array 620. Furthermore, in some cases, radiating elements 632 of mid-band linear arrays 630-1 and 630-2 may be more likely to interact with radiating elements 722 of high-band array 720. Therefore, by mounting linear arrays 630-1 and 630-2 further downward on backplate 610, the isolation between mid-band radiating elements 632 and high-band radiating elements 722 can be improved.

[0093] like Figure 6D As shown, in some cases, the low-band radiating elements 622 and the high-band radiating elements 722 may tend to have very limited coupling therebetween. In such cases, one or more of the low-band radiating elements 622 may be positioned within an opening within the high-band array 720. Figure 6D The base station antenna 602 uses a cross-polarized low-band radiating element 622 with horizontal and vertical polarizations instead of tilted +45° / -45° polarizations, which is why the "+" symbol is used to indicate Figure 6D The reason for including low-band radiating elements 622 in the antenna 602 is that the antenna 602 is not cross-polarized at +45° / -45°, rather than using an "X" as used in other figures to represent tilted +45° / -45° cross-polarized low-band radiating elements. A design of the base station antenna 602 in which one or more of the low-band radiating elements 622 are interleaved between high-band radiating elements 722 can reduce the overall length of the antenna, which can be advantageous in terms of aesthetics and cost. Such a design also makes it possible to include an array 720 of high-band radiating elements 722 in an antenna that includes a relatively large number of low-band radiating elements 622 and mid-band radiating elements 632.

[0094] It should be appreciated that the embodiments of the present invention described above are merely examples. For example, while the figures illustrate antennas with a specific number of arrays and radiating elements, other embodiments may include more or fewer arrays of each type and more or fewer radiating elements. Therefore, it should be appreciated that the technology disclosed herein can be used on a wide range of different base station antennas. As another example, the base station antenna described above has a radome mounted on the front of the antenna. In other embodiments, the radome may extend all the way around the antenna. Many other variations are possible.

[0095] It should be appreciated that a low-band radiating element can be a "wideband" radiating element that supports multiple different types of cellular services in the low-band frequency range. Likewise, a mid-band radiating element can be a "wideband" radiating element that supports multiple different types of cellular services in the mid-band frequency range. Thus, a multi-band antenna according to embodiments of the present application can support multiple different types of cellular services in one or more frequency bands by using such a wideband radiating element and using a diplexer to separate signals in two different cellular services received by the wideband radiating element and to combine signals in two different cellular services fed to the wideband radiating element.

[0096] Embodiments of the present application have been described above with the aid of functional descriptions and structural descriptions of embodiments of the application. It is evident, however, that the application can be practiced in many different forms and should not be construed as limited to the embodiments set forth in this disclosure. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art. The same applies to the accompanying drawings.

[0097] It should be understood that, although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0098] 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 appreciated by those of skill in the art that references to one element "connecting" or "coupling" to another element includes indirect connections or couplings, and intervening elements can also be present. In contrast, references to one element "directly connecting" or "directly coupling" to another element indicate that there are no intervening elements present. Other words of comparison used to describe relationships between elements should be interpreted in a like fashion (i.e., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

[0099] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" can be used herein for the purpose of describing one element, layer or region's relationship to another element, layer or region as shown in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.

[0100] 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" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0101] Aspects and elements of all the embodiments disclosed above can be combined in any manner and / or combination with aspects or elements of other embodiments to provide a number of additional embodiments.

Claims

1. A base station antenna unit, comprising: The first base station antenna comprises: first shell, a first radome having a front surface positioned in front of the first housing, a first vertically arranged linear array of first frequency band radiating elements, mounted behind the front surface of the first radome, and a second vertically disposed linear array of second frequency band radiating elements mounted behind the front surface of the first radome; and The second base station antenna comprises: a second radome having a front surface, and a third planar array of third frequency band radiating elements mounted behind the front surface of the second radome, the third planar array comprising at least four vertical columns of high frequency band radiating elements, wherein the first base station antenna and the second base station antenna are mounted in a vertically stacked arrangement, The horizontal width of the first radome is the same as the horizontal width of the second radome. wherein the front surface of the first radome and the front surface of the second radome are vertically aligned, wherein the lowermost portion of the second base station antenna is located within four inches of the uppermost portion of the first base station antenna, The second vertically arranged linear array is positioned farther from the third planar array in the vertical direction than the first vertically arranged linear array.

2. The base station antenna unit according to claim 1, wherein: The lowermost portion of the second base station antenna is located within two inches of the uppermost portion of the first base station antenna.

3. The base station antenna unit according to claim 1, wherein: The bottom of the second base station antenna directly contacts the top of the first base station antenna.

4. The base station antenna unit according to any one of claims 1 to 3, wherein: The uppermost first frequency band radiating element is mounted higher on the back panel than the uppermost second frequency band radiating element.

5. The base station antenna unit according to any one of claims 1 to 3, wherein: The height of the second base station antenna along the vertical direction is less than 0.6 meters.

6. The base station antenna unit according to any one of claims 1 to 3, wherein: The third frequency band radiating element is connected to at least one third frequency band phase shifter comprising a preset electronic downtilt of at least two degrees.

7. A base station antenna unit, comprising: The first base station antenna comprises: first shell, a first radome having a front surface positioned in front of the first housing, a first vertically arranged linear array of first frequency band radiating elements, mounted behind the front surface of the first radome, and a second vertically disposed linear array of second frequency band radiating elements mounted behind the front surface of the first radome; and The second base station antenna comprises: a second radome having a front surface positioned in front of the second housing, and a third array of third frequency band radiating elements mounted behind the front surface of the second radome, wherein the first base station antenna and the second base station antenna are mounted in a vertically stacked arrangement, wherein the second base station antenna is mounted on top of the first base station antenna, wherein the third frequency band radiating element is connected to at least one third frequency band phase shifter, the at least one third frequency band phase shifter comprising a preset electronic downtilt of at least two degrees, wherein the first base station antenna and the second base station antenna are mounted in a vertically stacked arrangement and are configured to be mounted as a single structure, The second vertically arranged linear array is positioned farther from the third array in the vertical direction than the first vertically arranged linear array.

8. The base station antenna unit according to claim 7, wherein: The preset electronic downtilt is between two degrees and six degrees.

9. The base station antenna unit according to claim 7, wherein: The third array of third frequency band radiating elements is configured to have a greater amount of preset electronic downtilt than the first array of first frequency band radiating elements and / or the second array of second frequency band radiating elements.

10. The base station antenna unit according to any one of claims 7 to 9, wherein: The horizontal width of the first radome is the same as the horizontal width of the second radome, and the front surface of the first radome and the front surface of the second radome are vertically aligned.

11. A tri-band base station antenna, comprising: case; a radome having a front surface positioned in front of the housing; a first vertically disposed linear array of first frequency band radiating elements mounted behind the front surface of the radome; a second vertically disposed linear array of second frequency band radiating elements mounted behind the front surface of the radome; as well as a third plurality of arrays of third frequency band radiating elements mounted behind the front surface of the radome, wherein the third plurality of arrays of third frequency band radiating elements comprises a planar array of radiating elements, wherein the first array, the second array and the third array of radiating elements are mounted on a common backplane, and the backplane is mounted on or in the housing, wherein one or more of the first frequency band radiating elements are staggered between the third array of the third frequency band radiating elements, and the remaining first frequency band radiating elements of the first frequency band are positioned below the third array of the third frequency band radiating elements, and The second vertically arranged linear array is positioned farther from the third multi-column array in the vertical direction than the first vertically arranged linear array.

12. The tri-band base station antenna according to claim 11, wherein: The first frequency band radiating element includes a cross-polarized first frequency band radiating element having horizontal polarization and vertical polarization.

13. The tri-band base station antenna according to claim 11, wherein: The second frequency band radiating element and the third frequency band radiating element include a cross-polarized second frequency band radiating element with tilted +45° / -45° polarization and a cross-polarized third frequency band radiating element with tilted +45° / -45° polarization, respectively.

14. The tri-band base station antenna according to any one of claims 11 to 13, wherein: The planar array includes at least four vertical columns of third frequency band radiating elements.

15. The tri-band base station antenna according to any one of claims 11 to 13, wherein: The uppermost first frequency band radiating element is mounted higher on the back panel than the uppermost second frequency band radiating element.

16. The tri-band base station antenna of any one of claims 11-13, further comprising a fourth vertically arranged linear array of second-band radiating elements, the fourth vertically arranged linear array of second-band radiating elements being mounted behind the front surface of the radome.

17. The tri-band base station antenna according to claim 16, wherein: The vertical array of first frequency band radiating elements is disposed between two vertical arrays of second frequency band radiating elements.

18. The tri-band base station antenna according to any one of claims 11 to 13, further comprising a top end cap and a bottom end cap, wherein: A plurality of connectors configured to transmit RF signals in each of the first frequency band radiating element, the second frequency band radiating element, and the third frequency band radiating element are mounted within the opening in the bottom end cap.

19. The tri-band base station antenna according to any one of claims 11 to 13, wherein: The first frequency band radiating element is connected to at least one first frequency band phase shifter, the second frequency band radiating element is connected to at least one second frequency band phase shifter, and the third frequency band radiating element is connected to at least one third frequency band phase shifter.

20. The tri-band base station antenna according to any one of claims 11 to 13, wherein: The first frequency band radiating element is configured to operate in a frequency band below 1.0 GHz, the second frequency band radiating element is configured to operate in a frequency band of 1.0 to 3.0 GHz, and the third frequency band radiating element is configured to operate in a frequency band of 3.5 to 5.0 GHz.

21. The tri-band base station antenna according to any one of claims 11 to 13, wherein: One or more radiating elements in the second frequency band linear array are positioned lower on the backplane than radiating elements in the first frequency band linear array.

22. A tri-band base station antenna, comprising: case; a radome having a front surface positioned in front of the housing; a first vertically disposed linear array of first frequency band radiating elements mounted behind the front surface of the radome; a second vertically disposed linear array of second frequency band radiating elements mounted behind the front surface of the radome; as well as a third multi-column array of third frequency band radiating elements mounted behind the front surface of the radome, wherein the third array of third frequency band radiating elements comprises a planar array of radiating elements comprising at least four vertical columns of third frequency band radiating elements, wherein the first array, the second array and the third array of radiating elements are mounted on a common backplane, and the backplane is mounted on or in the housing, wherein one or more of the first frequency band radiating elements are staggered between the third array of the third frequency band radiating elements, and the remaining first frequency band radiating elements of the first frequency band are positioned below the third array of the third frequency band radiating elements, and The second vertically arranged linear array is positioned farther from the third multi-column array in the vertical direction than the first vertically arranged linear array.

23. The tri-band base station antenna of claim 22, wherein: The first frequency band radiating element includes a cross-polarized first frequency band radiating element having horizontal polarization and vertical polarization.

24. The tri-band base station antenna of claim 22, wherein: The second frequency band radiating element and the third frequency band radiating element include a cross-polarized second frequency band radiating element with tilted +45° / -45° polarization and a cross-polarized third frequency band radiating element with tilted +45° / -45° polarization, respectively.

25. The tri-band base station antenna according to any one of claims 22 to 24, wherein: The uppermost first frequency band radiating element is mounted higher on the back panel than the uppermost second frequency band radiating element.

26. The tri-band base station antenna of any one of claims 22-24, further comprising a fourth vertically arranged linear array of second band radiating elements, the fourth vertically arranged linear array of second band radiating elements being mounted behind the front surface of the radome.

27. The tri-band base station antenna according to any one of claims 22 to 24, wherein: The vertical array of first-band radiating elements is disposed between the vertical array of second-band radiating elements.

28. The tri-band base station antenna according to any one of claims 22 to 24, wherein: The first frequency band radiating element is connected to at least one first frequency band phase shifter, the second frequency band radiating element is connected to at least one second frequency band phase shifter, and the third frequency band radiating element is connected to at least one third frequency band phase shifter.

29. The tri-band base station antenna according to any one of claims 22 to 24, wherein: The first frequency band radiating element is configured to operate in a frequency band below 1.0 GHz, the second frequency band radiating element is configured to operate in a frequency band of 1.0 to 3.0 GHz, and the third frequency band radiating element is configured to operate in a frequency band of 3.5 to 5.0 GHz.

30. The tri-band base station antenna of claim 27, wherein: One or more radiating elements in the second frequency band linear array are positioned lower on the backplane than radiating elements in the first frequency band linear array.

31. A base station antenna unit, comprising: a first base station antenna comprising a first housing having a first bottom end cap, wherein the first base station antenna comprises a first vertically disposed linear array of first frequency band radiating elements and a second vertically disposed linear array of second frequency band radiating elements; and a second base station antenna, the second base station antenna comprising a second housing having a second bottom end cap, the second base station antenna being mounted in a vertically stacked arrangement directly above the first base station antenna, wherein the second base station antenna comprises a planar array of radiating elements for a third frequency band; The upper portion of the second shell extends further rearward than the lower portion of the second shell to define a lip, the base plate forms a bottom surface of the lip, and a plurality of connectors are mounted in openings of the base plate.

32. The base station antenna unit of claim 31, wherein: The first base station antenna and the second base station antenna are configured to be mounted as a single structure.

33. The base station antenna unit according to claim 31, wherein: At least some of the connectors have respective longitudinal axes extending in a vertical direction.

34. The base station antenna unit according to any one of claims 31 to 33, wherein: A circumference of a first horizontal cross section passing through a central portion of the first base station antenna is the same as a circumference of a second horizontal cross section passing through a central portion of the second base station antenna.

35. The base station antenna unit of claim 33, wherein: The lowermost portion of the second base station antenna is located within four inches of the uppermost portion of the first base station antenna.

36. The base station antenna unit according to any one of claims 31 to 33, wherein: The maximum horizontal depth of the first base station antenna is smaller than the maximum horizontal depth of the second base station antenna.

37. The base station antenna unit of claim 32, wherein: The first base station antenna and the second base station antenna share a common radome.

38. A base station antenna, comprising: Back panel; a first vertically disposed linear array of first frequency band radiating elements mounted in front of the backplane; a second vertically disposed linear array of second frequency band radiating elements mounted in front of the backplane; as well as a third two-dimensional multi-column array of third frequency band radiating elements mounted on the front of the back panel, wherein when the base station antenna is mounted for use, the uppermost plurality of third frequency band radiating elements are mounted on the front of the back panel to be higher than the uppermost first frequency band radiating element and the uppermost second frequency band radiating element, wherein the second vertically disposed linear array is positioned further away from the third two-dimensional multi-column array in a vertical direction than the first vertically disposed linear array, and One or more first-band radiating elements in the first vertically arranged linear array are interleaved between the third-band radiating elements of the third two-dimensional multi-column array, and the remaining first-band radiating elements in the first vertically arranged linear array are positioned below the third two-dimensional multi-column array.

39. The base station antenna according to claim 38, wherein: When the base station antenna is mounted for use, the third frequency band radiating element is tilted downwardly from a plane that is parallel to a plane defined by the horizon.

40. The base station antenna of claim 38, further comprising a fourth vertically arranged linear array of second frequency band radiating elements mounted on the front of the backplane, wherein The first vertically disposed linear array of first frequency band radiating elements is between the second vertically disposed linear array and the fourth vertically disposed linear array of second frequency band radiating elements.

41. The base station antenna according to any one of claims 38 to 40, wherein: Each first frequency band radiating element is a cross-polarized radiating element having a vertically oriented dipole and a horizontally oriented dipole.

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