Compact omnidirectional antenna with stacked reflector structure

Abstract

The present invention relates to a compact omnidirectional antenna with a stacked reflector structure. A base station antenna comprises: a first reflector structure extending along a first longitudinal axis, the first reflector structure having a first cross-section; a second reflector structure extending along a second longitudinal axis, the second reflector structure having a second cross-section different from the first cross-section, the second reflector structure extending above the first reflector structure; a first array of first-band radiating elements mounted to extend outwardly from the first reflector structure; a second array of second-band radiating elements mounted to extend outwardly from the second reflector structure, the first frequency band not overlapping the second frequency band; and a radome extending around the first reflector structure and the second reflector structure.

Description

Technical Field

[0001] The present invention relates to cellular communication systems and, more particularly, to base station antennas for small cell cellular base stations. Background Art

[0002] Cellular communication systems are well known in the art. In a typical cellular communication system, a geographic area is divided into a series of areas, which are called "cells", and each cell is served by a base station. Typically, a cell can serve users within, for example, 2-20 kilometers from the base station. The base station may include baseband equipment, radio equipment, and antennas configured to provide two-way radio frequency ("RF") communications with fixed and mobile registered users ("users") located throughout the cell. The antennas are typically mounted on a tower, wherein the radiation beam ("antenna beam") generated by each antenna is directed outward. Typically, the base station antenna includes one or more phased array radiating elements, wherein the radiating elements are arranged in one or more vertical columns when the antenna is mounted for use. Here, "vertical" refers to a direction perpendicular to a plane defined by the horizon.

[0003] To increase capacity, cellular operators have deployed so-called "small cell" cellular base stations. A small cell base station refers to a low-power base station that can operate in a licensed and / or unlicensed spectrum with a smaller range than a typical "macro cell" base station. A small cell base station can be designed to serve users within a small geographic area (e.g., an area with a radius of tens or hundreds of meters). For example, a small cell can be used to provide cellular coverage to a high-traffic area within a macro cell, which allows the macro cell base station to offload most or all of the traffic near the small cell base station. Small cell base stations typically use antennas that provide full 360-degree coverage in the horizontal "azimuth" plane and appropriate beamwidth in the vertical "elevation" plane to cover the design area of ​​the small cell. The antenna on the small cell base station can be designed to have a small downtilt angle in the elevation plane to reduce the antenna beam formed thereby from spilling over to areas outside the small cell, and also to reduce interference between the small cell and the covering macro cell.

[0004] Figure 1A FIG. 1 is a schematic diagram of a conventional small cell base station 10. Figure 1A As shown, the base station 10 includes an antenna 20 that may be mounted on a lifting structure 30. The antenna 20 may have an omnidirectional antenna pattern in the azimuth plane, meaning that the antenna beam generated by the antenna 20 may extend through a full 360 degree circle in the azimuth plane.

[0005] like Figure 1A As further shown in FIG. 1 , the small cell base station 10 also includes base station equipment, such as a baseband unit 40 and a radio device 42 . Figure 1A 4 and 5. A single baseband unit 40 and a single radio 42 are shown in the figure to simplify the drawing. In addition, although the radio 42 is shown co-located with the baseband device 40 at the bottom of the antenna tower 30, it is understood that in other cases, the radio 42 can be a remote radio head mounted on the antenna tower 30 near the antenna 20. The baseband unit 40 can receive data from another source (such as, for example, a backhaul network (not shown)), and can process the data and provide a data stream to the radio 42. The radio 42 can generate RF signals including data encoded therein and can amplify and transmit these RF signals to the antenna 20 via a cable connection 44 for transmission. Figure 1A A base station will typically include various other equipment (not shown) such as, for example, a power supply, a backup battery, a power bus, etc.

[0006] Figure 1B is a composite diagram of several views of an antenna beam 50 produced by antenna 20, which has an omnidirectional pattern in the azimuth plane. Figure 1B Included is a perspective three-dimensional view of the antenna beam 50 (labeled "3D Pattern") and a graph of its azimuth and elevation patterns. The azimuth pattern is generated by taking a horizontal cross section in the middle of the three-dimensional antenna beam 50, and the elevation pattern is generated by taking a vertical cross section in the middle of the three-dimensional beam 50. It can be seen that the antenna beam 50 extends through a full 360 degrees in the azimuth plane, and the antenna beam 50 can have a nearly constant gain in all directions in the azimuth plane. In the elevation plane, the antenna beam 50 has high gain at elevation angles close to the horizon (e.g., elevation angles between -10° and 10°), but the gain drops significantly at larger elevation angles above and below the horizon. Therefore, the antenna beam 50 is omnidirectional in the azimuth plane and directional in the elevation plane.

[0007] Figure 2A is a schematic diagram illustrating a conventional small cell base station antenna 100 that forms four antenna beams with a peanut-shaped azimuth pattern to provide small cell coverage with MIMO capabilities. Antenna 100 is disclosed in U.S. Patent Publication No. 2018 / 0227775 (the '775 publication), published on August 9, 2018, the entire contents of which are incorporated herein by reference. A peanut-shaped azimuth pattern refers to an antenna pattern having a dual-lobe cross-section through the azimuth plane, wherein the two lobes extend away from the antenna in opposite directions. Figure 2AAs shown, the small cell base station antenna 100 includes a tubular reflector assembly 110 having a rectangular cross-section. Each face 114 of the reflector assembly 110 may include back panels 112-1 to 112-4. The base station antenna 100 includes a total of four linear arrays 120-1 to 120-4 of radiating elements 122 mounted on the corresponding back panels 112. Each back panel 112 may include, for example, a reflector used as a ground plane for the radiating element 122. When the base station antenna 100 is installed for use, each linear array 120 may be oriented vertically relative to the horizon. Each radiating element 122 may be a cross-polarized radiating element including a first dipole radiator that radiates RF energy with a tilted -45° polarization and a second dipole radiator that radiates RF energy with a tilted +45° polarization. The base station antenna 100 also includes a radome 102 that covers and protects the radiating element 122. It should be noted that, herein, when multiple similar or similar elements are provided, they may be labeled in the drawings using two-part reference numerals (e.g., linear array 120-1). These elements may be referred to herein individually by their full reference numerals (eg, face 214 - 2 ) and collectively by the first portion of their reference numerals (eg, linear array 120 ).

[0008] The base station antenna 100 has four RF ports (not shown). The first RF port is connected to the -45° dipole radiator of the radiating element 122 in the first linear array 120-1 and the third linear array 120-3, which are mounted on opposite back panels 112-1, 112-3. The second RF port is connected to the -45° dipole radiator of the radiating element 122 in the second linear array 120-2 and the fourth linear array 120-4, which are mounted on opposite back panels 112-2, 112-4. The third RF port is connected to the +45° dipole radiator of the radiating element 122 in the first linear array 120-1 and the third linear array 120-3. Finally, the fourth RF port is connected to the +45° dipole radiator of the radiating element 122 in the second linear array 120-2 and the fourth linear array 120-4. Figure 2B is a graph showing simulated antenna beams (in the azimuth plane) generated by the first RF port and the second RF port. Figure 2BAs shown, the -45° radiators of the radiating elements 122 included in the first linear array 120-1 and the third linear array 120-3 together form a first antenna beam 104-1, which also has a peanut-shaped cross-section in the azimuth plane. Similarly, the -45° radiators of the radiating elements 122 included in the second linear array 120-2 and the fourth linear array 120-4 together form a second antenna beam 104-2, which also has a peanut-shaped cross-section in the azimuth plane. The antenna beams 104-1 and 104-2 together can provide omnidirectional coverage in the azimuth plane. Summary of the invention

[0009] According to some embodiments of the present invention, a base station antenna is provided, which includes: a first reflector structure extending along a first longitudinal axis, the first reflector structure having a first cross-section; a second reflector structure extending along a second longitudinal axis, the second reflector structure having a second cross-section different from the first cross-section, the second reflector structure extending above the first reflector structure; a first array of first-band radiating elements, which are installed to extend outward from the first reflector structure; a second array of second-band radiating elements, which are installed to extend outward from the second reflector structure, the first frequency band does not overlap with the second frequency band; and a radome extending around the first reflector structure and the second reflector structure.

[0010] According to some embodiments of the present invention, a base station antenna is provided, which includes: a radar cover extending along a longitudinal axis; a first array of first frequency band radiating elements, the first frequency band radiating elements being at a first distance from the longitudinal axis; and a second array of second frequency band radiating elements, the second frequency band radiating elements being at a second distance from the longitudinal axis, the second distance being greater than the first distance, the second frequency band being different from the first frequency band, wherein the first array is longitudinally offset from the second array.

[0011] According to some embodiments of the present invention, a base station antenna is provided, comprising: a first reflector structure having a first side and a second side that are substantially opposite; a first array of radiating elements that are mounted to extend outwardly from the first side of the first reflector structure; and a second array of radiating elements that are mounted to extend outwardly from the second side of the first reflector structure; a second reflector structure having a third side and a fourth side that are substantially opposite; and a third array of radiating elements that are mounted to extend outwardly from the third side of the second reflector structure; and a fourth array of radiating elements that are mounted to extend outwardly from the fourth side of the second reflector structure, wherein the first side is a first distance from the second side, the third side is a second distance from the fourth side, and wherein the second distance is different from the first distance.

[0012] According to some embodiments of the present invention, a base station antenna is provided, which includes: a first reflector structure, which extends along a first longitudinal axis and has a cross-section with a first perimeter; a plurality of arrays of first-band radiating elements, which are installed to extend outward from corresponding sides of the first reflector structure; a second reflector structure, which extends along a second longitudinal axis and has a cross-section with a second perimeter, the second perimeter being different from the first perimeter; and a plurality of arrays of second-band radiating elements, which are installed to extend outward from corresponding sides of the second reflector structure, the first-band radiating elements and the second-band radiating elements having different configurations. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1A is a simplified schematic diagram showing a conventional small cell cellular base station.

[0014] Figure 1B Provides a Figure 1A Several views of antenna beams generated by antennas of a conventional small cell base station.

[0015] Figure 2A is a schematic diagram showing a conventional small cell base station antenna producing an antenna beam with a peanut-shaped azimuth pattern.

[0016] Figure 2B It is shown by Figure 2A Figure 2 is a graph of simulated azimuth patterns of two of the antenna beams generated by the small cell antenna.

[0017] Figure 3A is a schematic front view of a small cell base station antenna according to an embodiment of the present invention, wherein the front half of its radome is removed.

[0018] Figure 3B and 3C Along the Figure 3A Schematic cross-sectional views taken along lines 3B-3B and 3C-3C in FIG.

[0019] Figure 3D yes Figure 3A A perspective cutaway view of a portion of an antenna.

[0020] Figures 4A-4D is included in Figures 3A-3D Various views of the high-band radiating element in an antenna.

[0021] Figure 5-7 It is shown that it can be included in Figures 3A-3D Block diagram of the feeding network in a base station antenna.

[0022] Fig. 8A is a schematic front view of an omnidirectional small cell base station antenna with a single reflector structure.

[0023] Figure 8B is a schematic front view of another omnidirectional small cell base station antenna with a single reflector structure.

[0024] Figures 9A-9E is a schematic cross-sectional view of a stacked reflector structure of a small cell base station antenna according to other embodiments of the present invention.

[0025] Fig.10 is a schematic diagram of a base station antenna according to another embodiment of the present invention, which includes three stacked reflector structures. DETAILED DESCRIPTION

[0026] With the rollout of fifth generation cellular networks, cellular operators are now interested in small cell base station antennas that include linear arrays of radiating elements that operate in two, three, four or more different frequency bands. However, cellular operators also typically have strict requirements on the form factor of the small cell antenna, such as restrictions on the diameter, height and / or volume of the antenna. It can be challenging to design a small cell antenna that provides service in two, three, four or more different frequency bands while also meeting the form factor requirements specified by the cellular operator.

[0027] According to an embodiment of the present invention, a small cell antenna having a reflector assembly is provided, wherein the reflector assembly includes a plurality of vertically stacked tubular reflector structures having different horizontal (lateral) cross-sections. The stacked reflector structure can facilitate the installation of linear arrays of radiating elements operating in different frequency bands in a more compact arrangement. The linear arrays can be arranged on the stacked tubular reflector structures in such a manner as to provide a desired antenna beam shape for each different frequency band while allowing the antenna to meet relatively stringent requirements, such as antenna diameter, height, and / or volume. The stacked tubular reflector structures can also provide increased mechanical strength, additional space for internal components of the antenna, and / or improved cable routing paths compared to alternative antenna designs using a single tubular reflector structure.

[0028] In some embodiments, the small cell antenna may include a first group of four arrays of radiating elements mounted on the four main faces of the first tubular reflector structure. The first array and the third array may be mounted on opposite faces of the first tubular reflector structure and may be fed together to produce a first antenna beam having a peanut-shaped cross-section in the azimuth plane. The second array and the fourth array may be mounted on the other two opposite faces of the first tubular reflector structure and may be fed together to produce a second antenna beam also having a peanut-shaped cross-section in the azimuth plane. The second antenna beam may have substantially the same shape as the first antenna beam and may be rotated approximately ninety degrees in the azimuth plane relative to the first antenna beam. The first antenna beam and the second antenna beam together may provide omnidirectional coverage in the azimuth plane. The small cell antenna may also include a second group of four arrays of radiating elements mounted on the four main faces of the second tubular reflector structure. The four arrays in the second group of arrays may be mounted and fed in the same manner as the first group of arrays to produce a first antenna beam and a second antenna beam having a peanut-shaped cross-section in the azimuth plane, and together they provide omnidirectional coverage in the azimuth plane.

[0029] In some embodiments, the small cell base station antenna may include a first tubular reflector structure having a rectangular cross-section and a second tubular reflector structure having an octagonal cross-section. The rectangular cross-section of the first tubular reflector structure may have a first perimeter, and the octagonal cross-section of the second tubular reflector structure may have a second perimeter greater than the first perimeter. In some embodiments, the second perimeter may be at least 50% greater than the first perimeter. In other embodiments, the second perimeter may be at least twice the first perimeter. A linear array of radiating elements operating in a first frequency band may be mounted on at least two of the faces of the first tubular reflector structure having a rectangular cross-section, and a linear array of radiating elements operating in a second frequency band may be mounted on at least four of the sides of the second tubular reflector structure having an octagonal cross-section. The first frequency band may be, for example, a low frequency band (e.g., some or all of the 544-960 MHz frequency band), and the second frequency band may be, for example, a mid-frequency band (e.g., some or all of the 1.427-2.696 GHz frequency band).

[0030] In other embodiments, the small cell base station antenna may include a first tubular reflector structure having a first cross-section and a second tubular reflector structure having a second cross-section having a size and / or shape different from the first cross-section. The first reflector structure and the second reflector structure may be stacked vertically. A linear array of radiating elements operating in a first frequency band may be mounted on at least two of the faces of the first tubular reflector structure, and a linear array of radiating elements operating in a second frequency band may be mounted on at least two of the faces of the second tubular reflector structure. In an exemplary embodiment, the first reflector structure may have a rectangular or octagonal cross-section, and the second reflector structure may have an octagonal cross-section. The radome may surround the two reflector structures.

[0031] In some embodiments, the first perimeter of the first cross-section may be different from the second perimeter of the second cross-section. In embodiments where the second frequency band is higher than the first frequency band, the second perimeter may be greater than the first perimeter. The antenna may also include a linear array of radiating elements operating in a third frequency band that is higher than the first frequency band or the second frequency band. In some embodiments, these linear arrays may be mounted on the first reflector structure.

[0032] In other embodiments, a base station antenna may be provided that includes a first array of first frequency band radiating elements and a second array of second frequency band radiating elements offset from one another along a longitudinal axis of the antenna. The first frequency band radiating elements are a first distance from the longitudinal axis and the second frequency band radiating elements are a second distance from the longitudinal axis that is greater than the first distance. The second frequency band is different from the first frequency band and may be a higher frequency in some embodiments.

[0033] In other embodiments, a base station antenna may be provided that includes: a first reflector structure having a first side and a second side that are generally opposite; a first array of radiating elements mounted to extend outwardly from the first side of the first reflector structure and a second array of radiating elements mounted to extend outwardly from the second side of the first reflector structure; a second reflector structure having a third side and a fourth side that are generally opposite; a third array of radiating elements mounted to extend outwardly from the third side of the second reflector structure and a fourth array of radiating elements mounted to extend outwardly from the fourth side of the second reflector structure. In these antennas, the first side may be a first distance from the second side, and the third side may be a second distance from the fourth side, wherein the second distance is different from the first distance.

[0034] In other embodiments, a base station antenna may be provided that includes: a first reflector structure extending along a first longitudinal axis and having a cross-section of a first perimeter; a plurality of arrays of first frequency band radiating elements mounted to extend outwardly from respective sides of the first reflector structure; a second reflector structure extending along a second longitudinal axis and having a cross-section of a second perimeter, the second perimeter being different from the first perimeter; and a plurality of arrays of second frequency band radiating elements mounted to extend outwardly from respective sides of the second reflector structure. In these antennas, the first frequency band radiating elements and the second frequency band radiating elements may be different from each other and may be configured to operate in different frequency bands.

[0035] Exemplary embodiments of the present invention will now be discussed in more detail with reference to the accompanying drawings.

[0036] With the introduction of various fourth generation ("4G") and fifth generation ("5G") cellular technologies, base stations are employing antennas with multiple input multiple output ("MIMO") capabilities. As is known to those skilled in the art, MIMO refers to a technique in which data streams are separated and used to generate multiple RF signals, which are output through multiple ports of a radio device and transmitted through multiple different antenna arrays (or subarrays), for example, the antenna arrays (or subarrays) are spatially separated from each other and / or are in orthogonal polarizations. The RF signals are recovered at the receiving antennas, where they are demodulated and recombined to reconstruct the original data streams. Natural multipath propagation techniques based on spatial and / or polarization diversity are utilized so that the RF signals can be transmitted at the same frequency. The use of MIMO transmission techniques can help overcome the negative effects of multipath fading, reflections of transmitted signals from buildings, etc., to provide enhanced transmission quality and capacity.

[0037] Small cell base stations are often implemented in high-density urban environments. These environments may have many buildings, which makes them a natural application for using MIMO transmission technology. MIMO is often used in 4G applications because, although more expensive, the increased capacity often justifies the increased cost. If the cost of base station antennas with MIMO capabilities can be reduced, the benefits of using MIMO transmission technology can be further increased in terms of network capacity as a function of capital consumption.

[0038] A base station antenna that operates as a PxMIMO antenna (for a particular frequency band) refers to a base station antenna that divides a data stream into P parts (where P is a positive integer greater than 1) and transmits the P parts via different antenna arrays and / or with different polarizations. Thus, for example, a base station antenna designed to operate as a 4xMIMO antenna in a first frequency band will typically have two arrays of dual-polarized radiating elements that allow the antenna to produce two antenna beams (i.e., one for each array) in each of two orthogonal polarizations, thereby providing a total of four antenna beams for transmitting four separate data streams. As described above, a small cell base station antenna that operates in two, three, four, or more different frequency bands is required, where each frequency band implements 2xMIMO or 4xMIMO. Therefore, such a small cell base station antenna requires a large number of linear arrays of radiating elements of different sizes (because the size of the radiating element varies with frequency). It may be difficult to design and implement a base station antenna that provides this capability while also keeping the antenna's form factor within the constraints required by many cellular operators.

[0039] Figures 3A-3D 2 are various views showing a base station antenna 200 according to an embodiment of the present invention. In particular, Figure 3A is a schematic front perspective view of a base station antenna 200 with the front half of the radome removed and Figure 3B and 3C It is along Figure 3A Cross-sectional views taken along lines 3B-3B and 3C-3C. Figure 3D yes Figure 3A 1 is a perspective cutaway view of a portion of a base station antenna 200 .

[0040] like Figure 3A As shown, the base station antenna 200 includes a reflector assembly 210, which includes a first tubular reflector structure 212 and a second tubular reflector structure 216. The first tubular reflector structure 212 extends along a first longitudinal axis 213 and has a rectangular cross-section. Therefore, the first tubular reflector structure 212 has four main faces 214-1 to 214-4. The second tubular reflector structure 216 extends along a second longitudinal axis 217 and has an octagonal cross-section. Therefore, the second tubular reflector structure 216 has eight main faces 218-1 to 218-8. The first longitudinal axis 213 and the second longitudinal axis 217 can be collinear.

[0041] The small cell antenna 200 includes an array of radiating elements that operate in various different frequency bands. In particular, the antenna 200 includes four low-band arrays 220 of low-band radiating elements 222 that operate in some or all of the 544-960 MHz frequency band. Figures 3A-3CAs shown, each low-band array 220 may include two vertically stacked linear arrays of low-band radiating elements 222. Antenna 200 also includes eight mid-band arrays 230 of mid-band radiating elements 232 that operate in some or all of the 1427-2696 MHz frequency band. Figures 3A-3C As shown, each mid-band array 230 can include a linear array of five vertically stacked mid-band radiating elements 232. The antenna 200 also includes four high-band arrays 240 of high-band radiating elements 242. For example, the high-band radiating elements 242 can be configured to operate in some or all of the 3.3-4.2 GHz frequency band (referred to herein as the 3.5 GHz frequency band) and / or can be configured to operate in some or all of the 5.1-5.3 GHz frequency band (referred to herein as the 5 GHz frequency band). As will be explained in further detail below, in the depicted embodiment, the high-band radiating elements are dual-band radiating elements that are configured to operate in some or all of both the 3.5 GHz and 5 GHz frequency bands. Figures 3A-3C As shown, each high-band array 240 may include three vertically stacked linear arrays of high-band radiating elements 242. The base station antenna 200 may also include a radome 202 that covers and protects the radiating elements 222, 232, 242 and other components of the base station antenna 200.

[0042] Although the base station antenna 200 shows an exemplary embodiment, it should be understood that many changes can be made thereto. For example, in other embodiments, only two different types of linear arrays 220, 230, 240 may be provided (e.g., low frequency and medium frequency, medium frequency and high frequency, or low frequency and high frequency). As another example, the number of each type of linear array 220, 230, 240 may be changed, or the number of radiating elements 222, 232, 242 included in each type of linear array 220, 230, 240 may be changed (including arrays with a single radiating element). It should also be understood that any suitable radiating element 222, 232, 242 may be used, including, for example, dipoles, cross-dipoles, and / or patch radiating elements.

[0043] The low-band radiating elements 222 in the four low-band linear arrays 220 are mounted to extend forward from the corresponding four main faces 214 of the first tubular reflector structure 212 having a rectangular cross-section. Each main face 214 of the first tubular reflector structure 212 may include a back plate, which is used as a reflector and a ground plane for the low-band radiating elements 222 mounted thereon, for example. The first tubular reflector structure 212 may include a single structure or may include a plurality of structures attached together. When the base station antenna 200 is installed for use, each low-band linear array 220 is vertically oriented relative to the horizon. In the depicted embodiment, each low-band radiating element 222 includes a pair of dipole radiators 226, which are arranged orthogonally to each other at angles of -45° and +45° relative to the longitudinal (vertical) axis of the antenna 200.

[0044] The mid-band radiating elements 232 in the eight mid-band linear arrays 230 are mounted to extend forward from the corresponding eight main faces 218 of the second tubular reflector structure 216 having an octagonal cross-section. Each main face 218 of the second tubular reflector structure 216 may include a back plate, which serves as a reflector and as a ground plane for the mid-band radiating elements 232 mounted thereon, for example. The second tubular reflector structure 216 may include a single structure or may include multiple structures attached together. When the base station antenna 200 is installed for use, each mid-band linear array 230 is oriented vertically relative to the horizon. In the depicted embodiment, each mid-band radiating element 232 includes a pair of dipole radiators 236, which are arranged orthogonally to each other at angles of -45° and +45° relative to the longitudinal (vertical) axis of the antenna 200.

[0045] The high-band radiating elements 242 in the four high-band linear arrays 240 are mounted to extend forward from the corresponding four main faces 214 of the first tubular reflector structure 212. When the base station antenna 200 is installed for use, each high-band linear array 240 is vertically oriented relative to the horizon. Each high-band radiating element 242 is configured to transmit and receive signals in two different frequency bands. In the depicted embodiment, each high-band radiating element 242 includes: a first pair of dipole radiators 245, which are arranged orthogonally to each other at angles of -45° and +45° relative to the longitudinal (vertical) axis of the antenna 200; and a second pair of dipole radiators 246 arranged similarly. In the depicted embodiment, each high-band radiating element 242 is a cross-polarized radiating element, which is configured to transmit and receive signals in each frequency band with two orthogonal polarizations (i.e., -45° and +45° linear orthogonal polarizations).

[0046] Figures 4A-4D 2 are various views of one of the high-band radiating elements 242. Figures 4A-4DAs shown, each high-band radiating element 242 can be formed using a pair of printed circuit boards 244-1, 244-2. Each printed circuit board 244 includes a 3.5 GHz dipole arm 245 and a 5 GHz dipole arm 246. When the high-band radiating element 242 is installed for use, the 5 GHz dipole arm 246 is located outside the 3.5 GHz dipole arm 245. The two 3.5 GHz dipole arms 245 on the printed circuit board 244-1 form a first 3.5 GHz dipole radiator 247, which transmits and receives signals with a -45° polarization, and the two 3.5 GHz dipole arms 245 on the printed circuit board 244-2 form a second 3.5 GHz dipole radiator 247, which transmits and receives signals with a +45° polarization. Likewise, the two 5 GHz dipole arms 246 on the printed circuit board 244-1 form a first 5 GHz dipole radiator 248 that transmits and receives signals at -45° polarization, and the two 5 GHz dipole arms 246 on the printed circuit board 244-2 form a second 5 GHz dipole radiator 248 that transmits and receives signals at +45° polarization. The 3.5 GHz dipole arms 245 are driven directly through corresponding baluns 249. When a 3.5 GHz signal is input to the balun 249, it is fed directly to the 3.5 GHz dipole arms 245. When a 5 GHz signal is input to the balun 249, energy is electromagnetically coupled to the 5 GHz dipole arms 246, which then resonate at 5 GHz.

[0047] Figure 5 is a block diagram showing a feed network for the low-band array 220. Figure 5 As shown, the base station antenna 200 includes four low-band RF ports 250. These low-band RF ports 250 are connected to four corresponding ports of a low-band radio (not shown). The duplexing of the transmit and receive channels is performed internally in the radio, so each port on the low-band radio passes both the transmit and receive RF signals.

[0048] like Figure 5As shown, each RF port 250 is coupled to a corresponding 1×2 power splitter / combiner 252. Each 1×2 power splitter / combiner 252 is connected to two of the low-band linear arrays 220, wherein the linear arrays 220 are located on opposite major faces of the first tubular reflector structure 212. In particular, power splitter / combiner 252-1 is coupled to the -45° dipole radiators of radiating elements 222 in linear arrays 220-1 and 220-3, power splitter / combiner 252-2 is coupled to the +45° dipole radiators of radiating elements 222 in linear arrays 220-1 and 220-3, power splitter / combiner 252-3 is coupled to the -45° dipole radiators of radiating elements 222 in linear arrays 220-2 and 220-4, and power splitter / combiner 252-4 is coupled to the +45° dipole radiators of radiating elements 222 in linear arrays 220-2 and 220-4.

[0049] When referring to Figure 5 When the base station antenna 200 is fed in the manner discussed, the antenna 200 can generate two different low-band antenna beams at each of the two polarizations for a total of four antenna beams. In particular, a first -45° polarized antenna beam is generated by the linear arrays 220-1 and 220-3, and a second -45° polarized antenna beam is generated by the linear arrays 220-2 and 220-4. Similarly, a first +45° polarized antenna beam is generated by the linear arrays 220-1 and 220-3, and a second +45° polarized antenna beam is generated by the linear arrays 220-2 and 220-4. Based on the pointing directions of the linear arrays 220, each antenna beam can have a generally peanut-shaped cross-section in the azimuth plane because each antenna beam is generated by the linear arrays 220 pointing in opposite directions in the azimuth plane. The antenna beams are offset 90 degrees relative to each other in the azimuth plane and can be similar to Figure 2B The antenna beam 104 ( Figure 2B Two antenna beams 104) are shown generated in one of two polarizations.

[0050] The low-band linear array 220 can be configured to support 4×MIMO operation. 4×MIMO refers to an operating mode in which an antenna transmits RF signals in a particular frequency band along four substantially orthogonal paths. Here, the low-band linear array 220 generates two peanut-shaped antenna beams in each of two different orthogonal polarizations, and thus can support 4×MIMO operation.

[0051] In other embodiments, two of the ports on the low-band radio device can transmit and receive signals in a first sub-band within the low-band frequency range (e.g., all or part of the 710-787 MHz sub-band), while the other two ports on the low-band radio device can transmit and receive signals in a second sub-band within the low-band frequency range (e.g., all or part of the 806-896 MHz sub-band). In such an embodiment, the base station antenna 200 will only implement 2×MIMO in the low-band, but will be able to transmit and receive signals in two different sub-bands of the low-band frequency range. A null 106 in the azimuth pattern is created at the corner where the edges of the first tubular reflector structure 212 intersect (see Figure 2B ) is a function of frequency. Thus, while there may be relatively deep nulls 106 in the antenna beams produced by the mid-band and high-band linear arrays 230, 240 (producing peanut-shaped patterns in the azimuth plane), the nulls 106 produced in the low-band may be much shallower. Thus, a single pair of linear arrays 220 mounted on opposite sides of the tubular reflector structure 212 may be used to produce a somewhat omnidirectional pattern in the azimuth plane. Thus, in some embodiments, the base station antenna 200 may implement 2×MIMO in two different sub-bands of the low-band.

[0052] Figure 6 An embodiment of a feed network is shown that may be used to pass RF signals between a mid-band base station radio (not shown) and four of the eight mid-band linear arrays 230. The mid-band radio may be an inter-duplex, four-port device, and the radio ports may be connected to four corresponding mid-band RF ports 260 on the antenna 200.

[0053] like Figure 6 As shown, the mid-band feed network is similar to that in the reference Figure 5The low-band feed network discussed. In particular, each mid-band RF port 260 is coupled to a corresponding 1×2 power divider / combiner 262. Each 1×2 power divider / combiner 262 is connected to two mid-band linear arrays 230 located on opposite major surfaces of the second tubular reflector structure 216. Eight phase shifters 264 are provided, wherein each phase shifter 264 is between a corresponding one of the output ends of the four 1×2 power dividers / combiners 262 and the four mid-band linear arrays 230 (for each mid-band linear array 230, the first phase shifter 264 is connected to the -45° dipole radiator 236 of the mid-band radiating element 232 in the array 230, and the second phase shifter 264 is connected to the +45° dipole radiator 236 of the mid-band radiating element 232 in the array 230). Each phase shifter 264 may split the RF signal input thereto into three ways (and the power split may be equal or unequal) and may apply phase tapers on the three subcomponents of the RF signal to, for example, apply electronic downtilt to the antenna beams formed when the subcomponents of the RF signal are transmitted (or received) by the corresponding linear array 320. The mid-band linear array 320 may support 4×MIMO operation.

[0054] As described above, the base station antenna may include a total of eight mid-band linear arrays 230 . Figure 6 The feed network shown may be used to support services in a first sub-band of the mid-band range (e.g., a 1710-1785 MHz sub-band) using four of the mid-band linear arrays 230. Antenna 200 may include a second sub-band feed network that may be used with Figure 6 The feed network shown is the same for supporting services in the second sub-band of the mid-band frequency range (eg, the 1920-1980 MHz sub-band) using the remaining four of the mid-band linear arrays 230 .

[0055] Figure 7 An embodiment of a feed network that can be used to pass RF signals between a 3.5 GHz base station radio (not shown) and a 5 GHz base station radio (not shown) and four linear arrays 240 of high band radiating elements 242 is shown. The 3.5 GHz radio can have four ports, while the 5 GHz radio can have two ports, and duplexing of the transmit and receive channels can be performed inside the radio. The four 3.5 GHz radio ports can be connected to the four 3.5 GHz RF ports 270-1, 270-2 included in the antenna 200, and the two 5 GHz radio ports can be connected to the 5 GHz RF ports 272-1, 270-2 included in the two antennas 200.

[0056] like Figure 7As shown, the high frequency band feeding network 200 can include a total of eight output terminals 278-1 to 278-8. Output terminals 278-1 and 278-5 are coupled to the linear array 240-1, output terminals 278-2 and 278-6 are coupled to the linear array 240-3, output terminals 278-3 and 278-7 are coupled to the linear array 240-2, and output terminals 278-4 and 278-8 are coupled to the linear array 240-4. The 3.5 GHz input terminals 270-1 and 270-2 can be connected to the first input terminals of the first and second duplexers 276-1 and 276-2. The 5 GHz input terminal 272-1 is connected to the input terminal of the first power coupler 274-1. The output terminal of the first power coupler 278-1 can be connected to the second input terminals of the first and second duplexers 276-1 and 276-2, respectively. The first and second duplexers 276-1, 276-2 can each receive both the 3.5 GHz signal and the 5 GHz signal, combine the signals, and output the combined signal to the corresponding second and third power couplers 274-2, 274-3. The output of the second power coupler 274-2 can be provided to the -45° dipole radiators 245, 246 of the radiating elements 242 in the linear arrays 240-1, 240-3, respectively, and the output of the third power coupler 274-3 can be provided to the -45° dipole radiators 245, 246 of the radiating elements 242 in the linear arrays 240-2, 240-4, respectively.

[0057] Thus, the first 3.5 GHz signal input at port 270-1 will be delivered to the -45° dipole radiators 245, 246 of the radiating elements 242 in the linear arrays 240-1, 240-3 to produce a first antenna beam having a peanut-shaped cross-section in the azimuth plane, and the second 3.5 GHz signal input at port 270-2 will be delivered to the -45° dipole radiators 245, 246 of the radiating elements 242 in the linear arrays 240-2, 240-4 to produce a second beam pattern having a peanut-shaped cross-section in the azimuth plane. The first 5 GHz signal input at port 272-1 will be delivered to the -45° dipole radiators 245, 246 of the radiating elements 242 in all four linear arrays 240-1 to 240-4 to produce an omnidirectional antenna beam in the azimuth plane. Figure 7 As shown, the +45° dipole radiator may be fed in exactly the same manner from the 3.5 GHz input ports 270-3, 270-4 and the 5 GHz input port 272-2 to form two additional peanut-shaped 3.5 GHz antenna beams and an additional omnidirectional 5 GHz antenna beam at +45° polarization.

[0058] As described above, the base station antenna includes a reflector assembly 210, which includes a pair of vertically stacked reflector structures 212, 216. Each reflector structure 212, 216 can have a different cross-section (in the depicted embodiment, the first reflector structure 212 has a rectangular cross-section, and the second reflector structure 216 has an octagonal cross-section). In addition, the corresponding perimeters of the cross-sections of the first and second reflector structures can be different. Therefore, the relative major faces 214 of the first reflector structure 212 can be spaced apart by a first distance, and the relative major faces 218 of the second reflector structure 216 can be spaced apart by a second distance different from the first distance. In some embodiments, the cross-section can be a regular or irregular polygonal shape, but embodiments of the present invention are not limited to this.

[0059] Providing a reflector assembly 210 including two or more vertically stacked reflector structures 212, 216 may provide a number of advantages over conventional reflector assemblies including a single reflector structure. Fig. 8A and 8B It can be seen that Fig. 8A and 8B Exemplary implementations of small cell base station antennas, each having a single reflector structure, are shown.

[0060] In particular, Fig. 8A A multi-band small cell antenna 300 is shown that includes four linear arrays 220 of low-band radiating elements 222, eight linear arrays 230 of mid-band radiating elements 232, and four linear arrays 240 of high-band radiating elements 242 mounted on a single reflector structure 310 that includes a square cross-section. The linear arrays and radiating elements are Fig. 8A Most of them are not numbered to simplify the drawings, but correspond to Figure 3A. Since the reflector structure 310 has only four main faces, two mid-band linear arrays 230 are mounted on each main face of the reflector structure 310 in a vertically stacked arrangement. Compared with the base station antenna 200 according to an embodiment of the present invention, this arrangement significantly extends the length of the antenna 300. In order to keep the diameter of the antenna 300 relatively small, the circumference of the reflector structure 310 is kept small. However, this design creates a very small space inside the antenna 300. If the antenna 300 includes a remote electronic downtilt for the mid-band linear array 230, there may not be enough space inside the reflector assembly 310 to install the RET motor and the mechanical linkage (linkage) connecting the RET motor to the phase shifter. It may also be difficult to arrange the RF cable inside the reflector structure. In addition, as the length of the reflector assembly 310 is extended, the overall strength of the reflector assembly 310 is reduced. This may require the use of thicker metal for the reflector assembly 310, or the addition of structural supports, both of which may increase the cost and weight of the antenna 300. Therefore, antenna 300 may be longer, heavier, and more expensive than base station antenna 200, and may also be more difficult to implement as a remote electronic downtilt antenna. Note that antenna 300 includes four low-band radiating elements 222 in each low-band array 220 because there is sufficient space for additional low-band radiating elements 222 in the design.

[0061] Figure 8B A multi-band small cell antenna 400 is shown, which also includes four linear arrays 220 of low-band radiating elements 222, eight linear arrays 230 of mid-band radiating elements 232, and four linear arrays 240 of high-band radiating elements 242 mounted on a single reflector assembly 410, the single reflector assembly having an octagonal cross-section. The eight mid-band linear arrays 230 are mounted on eight corresponding faces of the reflector structure 410. This allows the length of the antenna 400 to be significantly reduced compared to the antenna 300. In order to maintain appropriate separation between adjacent mid-band linear arrays 230, the perimeter of the cross-section of the reflector assembly 410 must be quite large. When the relatively tall low-band radiating element 222 is mounted on the reflector assembly 410, the diameter of the antenna 400 is significantly increased compared to the antenna 300. Unfortunately, the required diameter may exceed the diameter requirements specified by various cellular network operators for small cell base station antennas due to the need to often mount these antennas on relatively small diameter poles.

[0062] The base station antenna 200 according to the embodiment of the present invention overcomes the problem that Figures 8A-8B In particular, the base station antenna 200 may have a diameter of 14.5 inches or less and a length of 39 inches or less. Figure 3DAs shown, the second reflector structure 216 can have a relatively large open interior. This can leave enough room for the installed RET unit 290, mechanical link 292, and link plate 294 to be installed inside the antenna 200. The larger interior can also leave room for wiring inside the antenna. In addition, due to the reduced height of the antenna, the reflector structure can have sufficient strength without the need for thicker metal and / or separate support structures.

[0063] It should be appreciated that many different variations of the stacked reflector structures 212, 216 included in the base station antenna 200 may be used in other antenna designs where appropriate. For example, Figures 9A-9E is a schematic diagram showing a cross section of a stacked reflector structure of a base station antenna according to another embodiment of the present invention.

[0064] like Fig. 9A As shown, in one such embodiment, a base station antenna 500 is provided, which includes a reflector assembly having a first reflector structure 502 and a second reflector structure 504, wherein the first reflector structure has an octagonal cross-section, the second reflector structure has a larger octagonal cross-section, and the first reflector structure is vertically stacked relative to the second reflector structure. An antenna with such a configuration can be, for example, the same as the base station antenna 200 described above, except that the four high-band linear arrays 240 can be moved to the four faces of the first reflector structure 502 that do not include the low-band linear array 220. This design can reduce the coupling between the low-band radiating element 222 and the high-band radiating element 242.

[0065] like Fig. 9B As shown, in another exemplary embodiment, a base station antenna 510 is provided, which includes a reflector assembly having a first reflector structure 512 and a second reflector structure 514, wherein the first reflector structure has a cross-section in the shape of a rounded rectangle, the second reflector structure has an octagonal cross-section, and the first reflector structure is vertically stacked relative to the second reflector structure. The perimeter of the cross-section of the first reflector structure 512 is smaller than the perimeter of the cross-section of the second reflector structure 514. Fig. 9B The antenna of the construction may, for example, be identical to the base station antenna 200 described above, except that the first reflector structure 512 has rounded corners and therefore does not have a completely rectangular cross-section. Fig. 9B It is shown that the reflector structure used in the antenna according to the embodiment of the invention need not have a polygonal cross-section.

[0066] like Fig. 9CAs shown, in another exemplary embodiment, a base station antenna 520 is provided, which includes a reflector assembly having a first reflector structure 522 and a second reflector structure 524, wherein the first reflector structure has a rectangular cross-section, the second reflector structure has a hexagonal cross-section, and the first reflector structure is vertically stacked relative to the second reflector structure. The perimeter of the cross-section of the first reflector structure 522 is smaller than the perimeter of the cross-section of the second reflector structure 524. Fig. 9C The antenna of the configuration may, for example, include a mid-band linear array 230 located on each of the six faces of the second reflector structure 524, which is designed to cover most or all of the 120° sector in the azimuth plane. Three of the six mid-band linear arrays 230 located on non-adjacent faces of the second reflector structure 524 may support services in a first sub-band of the mid-band range, and the other three of the six mid-band linear arrays 230 may support services in a second sub-band of the mid-band range. Otherwise, the base station antenna 520 may be the same as the base station antenna 200 described above.

[0067] like Fig.9D As shown, in another exemplary embodiment, a base station antenna 530 is provided, which includes a reflector assembly having a first reflector structure 532 and a second reflector structure 534, wherein the first reflector structure has a hexagonal cross-section, the second reflector structure also has a hexagonal cross-section, and the first reflector structure is vertically stacked relative to the second reflector structure. The perimeter of the cross-section of the first reflector structure 532 is smaller than the perimeter of the cross-section of the second reflector structure 534. Fig.9D The antenna structure of can, for example: include a low-band linear array 220 on three non-adjacent faces of the six faces of the first reflector structure 532, which is designed to cover most or all of the 120° sector in the azimuth plane; include a high-band linear array 240 on the remaining three faces of the first reflector structure 532; and include a mid-band linear array 230 on each of the six faces of the second reflector structure 534, which is designed to cover most or all of the 120° sector in the azimuth plane, which is similar to the above reference Fig. 9C Constructed in the same manner as described.

[0068] like Fig.9E As shown, in yet another exemplary embodiment, a base station antenna 540 is provided, which includes a reflector assembly having a first reflector structure 542 and a second reflector structure 514, wherein the first reflector structure has an irregular octagonal cross-section, the second reflector structure has an octagonal cross-section, and the first reflector structure is vertically stacked relative to the second reflector structure. Except for a slight change in the cross-section of the first reflector structure 542, the antenna 540 can be the same as the antenna 510 discussed above. Fig.9E It is shown that the reflector structure used in the antenna according to the embodiment of the present invention may have an irregular polygonal cross section.

[0069] It should also be understood that in other embodiments of the present invention, a base station antenna comprising more than two vertically stacked reflector structures may be provided. Fig.10 An exemplary embodiment of such an antenna is shown. Fig.10 As shown, the base station antenna 600 includes a reflector assembly 610 having a first reflector structure 612, a second reflector structure 614, and a third reflector structure 616 stacked along a longitudinal axis. In this particular embodiment, the first reflector structure 612 has a rectangular cross-section, the second reflector structure 614 has an octagonal cross-section, and the third reflector structure 616 has a rectangular cross-section. The perimeter of the third reflector structure 616 is greater than the perimeter of the second reflector structure 614, and the perimeter of the second reflector structure 614 is greater than the perimeter of the first reflector structure 612. The low-band radiating elements 222 are mounted as four arrays on four corresponding faces of the first reflector structure 612, the mid-band radiating elements 232 are mounted as eight arrays on eight corresponding faces of the second reflector structure 614, and the high-band radiating elements 242 are mounted as four arrays on four corresponding faces of the third reflector structure 616. Antenna 600 may be nearly identical to base station antenna 200 described above, except that antenna 600 includes a separate reflector structure 616 having a larger cross-section for high-band reflective element 642. The larger cross-section of third reflector structure 616 may advantageously place high-band reflective element 242 closer to a radome (not shown), which may improve its performance; and may also create additional space inside the antenna, which may be used, for example, to mount a RET unit for a low-band or high-band array.

[0070] It should be understood that many modifications may be made to the above-described antennas without departing from the scope of the present invention. As an example, in the above-described embodiments, the various arrays of radiating elements are shown as vertically oriented linear arrays. However, it should be understood that staggered linear arrays may be used instead, as disclosed, for example, in U.S. Provisional Patent Application Serial No. 62 / 722,238 filed on August 24, 2018, the entire contents of which are incorporated herein by reference, or, in other embodiments, planar arrays of radiating elements may be used in place of the linear arrays shown in the accompanying drawings. As another example, although the high-band array is shown in the above-described embodiments as being mounted on the same reflector structure as the low-band array, in other embodiments, the high-band array and the mid-band array may be mounted on the same reflector structure.

[0071] The present invention has been described above with reference to the accompanying drawings. The present invention is not limited to the illustrated embodiments; rather, these embodiments are intended to fully and completely disclose the present invention to those skilled in the art. In the accompanying drawings, the same reference numerals always refer to the same elements. The thickness and size of some elements may not be drawn to scale.

[0072] For ease of explanation, spatial relative terms such as "lower", "below", "lower", "upper", "above", "top", "bottom", etc. may be used herein to describe the relationship between one element or feature shown in the figures and another element or feature. It should be understood that, in addition to the orientation shown in the figures, spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as "under" or "below" other elements or features will be oriented "above" the other elements or features. Therefore, the exemplary term "below" can cover the orientation of above and below. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein are interpreted accordingly.

[0073] For brevity and / or clarity, well-known functions or constructions may not be described in detail.As used herein, the expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0074] It should be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present invention.

Claims

1. A base station antenna, comprising: a first reflector structure extending about a first longitudinal axis, the first reflector structure having a first cross-section; a second reflector structure extending about a second longitudinal axis, the second reflector structure having a second cross-section having a shape different from the first cross-section, wherein the first reflector structure and the second reflector structure are vertically stacked; a first array of first frequency band radiating elements mounted to extend outwardly from said first reflector structure; a second array of second frequency band radiating elements mounted to extend outwardly from the second reflector structure, the first frequency band and the second frequency band not overlapping; and A radome extends around the first reflector structure and the second reflector structure. 2 . The base station antenna of claim 1 , wherein the first longitudinal axis and the second longitudinal axis are collinear. The base station antenna according to claim 1 , wherein the first cross section or the second cross section is an octagonal cross section. 4 . The base station antenna according to claim 3 , wherein the other of the first cross section or the second cross section is a rectangular cross section.

5. The base station antenna according to claim 1, wherein a first perimeter of the first cross-section is different from a second perimeter of the second cross-section, wherein the first cross-section is a rectangular cross-section and the second cross-section is an octagonal cross-section, wherein the base station antenna is a small cell antenna, The first perimeter of the first cross section is smaller than the second perimeter of the second cross section. 6 . The base station antenna according to claim 5 , wherein the frequency of the second frequency band is higher than the frequency of the first frequency band, and wherein the second perimeter is greater than the first perimeter.

7. The base station antenna of claim 6, further comprising a third array of third frequency band radiating elements mounted to extend outwardly from the first reflector structure, the third frequency band not overlapping either the first frequency band or the second frequency band.

8. The base station antenna of claim 1 , further comprising a third array of radiating elements mounted to extend outwardly from the first reflector structure, wherein the radiating elements of the first array and the third array are configured to generate a first antenna beam having a peanut-shaped cross-section in an azimuth plane.

9. A base station antenna, comprising: a first reflector structure having opposing first and second sides; a first array of radiating elements mounted to extend outwardly from a first side of the first reflector structure; and a second array of radiating elements mounted to extend outwardly from a second side of the first reflector structure; a second reflector structure having opposing third and fourth sides; and a third array of radiating elements mounted to extend outwardly from a third side of the second reflector structure; and a fourth array of radiating elements mounted to extend outwardly from a fourth side of the second reflector structure, wherein the first side is a first distance from the second side, the third side is a second distance from the fourth side, wherein the first reflector structure and the second reflector structure surround a longitudinally extending central channel, wherein the second distance is different from the first distance, and The radiating elements of the first array are configured to operate in a first frequency band, and at least one of the radiating elements of the second array or the radiating elements of the third array is configured to operate in a second frequency band having a higher frequency than the first frequency band.

10. The base station antenna according to claim 9, wherein the first reflector structure and the second reflector structure extend along a common longitudinal axis, and wherein the base station antenna further comprises an antenna cover extending around the first reflector structure and the second reflector structure, and is configured such that the first array, the second array, the third array, and the fourth array are located inside the antenna cover.

11. The base station antenna of claim 9, wherein the first reflector structure has a first cross-section and the second reflector structure has a second cross-section different from the first cross-section. 12 . The base station antenna according to claim 11 , wherein the first cross section is a rectangular cross section, and the second cross section is an octagonal cross section.

13. The base station antenna of claim 9, wherein the first reflector structure has a first cross-section and the second reflector structure has a second cross-section, and wherein the first cross-section is an octagonal cross-section and the second cross-section is an octagonal cross-section.

14. The base station antenna of claim 11, wherein a first perimeter of the first cross-section is different from a second perimeter of the second cross-section. The base station antenna of claim 14 , wherein the second perimeter is greater than the first perimeter.

16. A base station antenna, comprising: a first reflector structure having opposing first and second sides; a first array of radiating elements mounted to extend outwardly from a first side of the first reflector structure; and a second array of radiating elements mounted to extend outwardly from a second side of the first reflector structure; a second reflector structure having opposing third and fourth sides; a third array of radiating elements mounted to extend outwardly from a third side of the second reflector structure; and a fourth array of radiating elements mounted to extend outwardly from a fourth side of the second reflector structure, a fifth array of radiating elements mounted to extend outwardly from said first reflector structure; wherein the first side portion is at a first distance from the second side portion, the third side portion is at a second distance from the fourth side portion, and wherein the second distance is different from the first distance, wherein the first reflector structure has a first cross-section and the second reflector structure has a second cross-section different from the first cross-section, wherein a first perimeter of the first cross-section is different from a second perimeter of the second cross-section; Wherein the radiating elements of the first array are configured to operate in a first frequency band, and the radiating elements of the second array are configured to operate in a second frequency band having a frequency higher than the first frequency band, wherein the radiating elements of the fifth array are configured to operate in a third frequency band having a frequency higher than the second frequency band, and wherein the second perimeter is greater than the first perimeter.

17. A base station antenna, comprising: a first reflector structure extending along a first longitudinal axis and having a cross-section having a first perimeter; a plurality of arrays of first frequency band radiating elements mounted to extend outwardly from respective sides of the first reflector structure; a second reflector structure extending along a second longitudinal axis and having a cross-section having a second perimeter, the second perimeter being different from the first perimeter; and A plurality of arrays of second-band radiating elements are mounted to extend outwardly from respective sides of the second reflector structure, the first-band radiating elements and the second-band radiating elements having different configurations, wherein the plurality of arrays of first-band radiating elements protrude outwardly from the first reflector structure a first distance, and wherein the plurality of arrays of second-band radiating elements protrude outwardly from the second reflector structure a second distance, wherein the first distance is different from the second distance.

18. The base station antenna of claim 17, wherein the first reflector structure and the second reflector structure extend along a common longitudinal axis, and wherein the first reflector structure and the second reflector structure have a configuration extending completely around the longitudinal axis so as to enclose the longitudinal axis.

19. The base station antenna according to claim 18, wherein the cross-section of the first reflector structure is a rectangular cross-section, and the cross-section of the second reflector structure is an octagonal cross-section.

20. The base station antenna of claim 17, wherein the first frequency band radiating element is configured to operate in a first frequency band and the second frequency band radiating element is configured to operate in a second frequency band having a frequency higher than the first frequency band, wherein the second perimeter is greater than the first perimeter, and wherein the base station antenna further comprises an antenna cover extending around the first reflector structure and the second reflector structure.

21. A base station antenna, comprising: a first reflector structure extending along a first longitudinal axis and having a cross-section having a first perimeter; a plurality of arrays of first frequency band radiating elements mounted to extend outwardly from respective sides of the first reflector structure; a second reflector structure extending along a second longitudinal axis and having a cross-section having a second perimeter, the second perimeter being different from the first perimeter; and a plurality of arrays of second frequency band radiating elements mounted to extend outwardly from respective sides of the second reflector structure, the first frequency band radiating elements and the second frequency band radiating elements having different configurations; and a third array of radiating elements configured to operate in a third frequency band, wherein the third array is mounted to extend outwardly from the first reflector structure, Wherein the first frequency band radiating element is configured to operate in a first frequency band, and the second frequency band radiating element is configured to operate in a second frequency band having a higher frequency than the first frequency band, wherein the third frequency band has a higher frequency than the second frequency band, and wherein the second perimeter is greater than the first perimeter.

Images