The present disclosure relates to communication systems and, in particular, to multi-band base station antennas.
Base station antennas for wireless communication systems are used to transmit Radio Frequency (“RF”) signals to, and receive RF signals from, fixed and mobile users of a cellular communications service. Base station antennas often include a linear array or a two-dimensional array of radiating elements, such as dipole, or crossed dipole, radiating elements.
Example base station antennas are discussed in International Publication No. WO 2017/165512 to Bisiules and U.S. patent application Ser. No. 15/921,694 to Bisiules et al., the disclosures of which are hereby incorporated herein by reference in their entireties. Though it may be advantageous to incorporate multiple arrays of radiating elements in a single base station antenna, wind loading and other considerations often limit the number of arrays of radiating elements that can be included in a base station antenna.
A base station antenna, according to some embodiments herein, may include a reflector. The base station antenna may include first and second vertical columns of low-band radiating elements on a surface of the reflector and configured to transmit RF signals in a first frequency band. Moreover, the base station antenna may include eight vertical columns of high-band radiating elements on the surface of the reflector and configured to transmit RF signals in a second frequency band that is higher than the first frequency band. A dipole arm of one of the low-band radiating elements may overlie one of the high-band radiating elements in a direction that is perpendicular to the surface of the reflector.
In some embodiments, the first and second vertical columns of low-band radiating elements may be first and second outer columns, respectively, of low-band radiating elements. Moreover, the first and second outer columns of low-band radiating elements may be between outer ones of the eight vertical columns of high-band radiating elements.
According to some embodiments, the eight vertical columns of high-band radiating elements may have equal quantities of high-band radiating elements. For example, each of the eight vertical columns of high-band radiating elements may have sixteen high-band radiating elements.
In some embodiments, first and second vertical columns of the eight vertical columns of high-band radiating elements may be between the first and second vertical columns of low-band radiating elements. Feed points of the first vertical column of low-band radiating elements may be spaced apart from feed points of the second vertical column of low-band radiating elements by a horizontal distance equal to 0.4-0.8 of a wavelength of the first frequency band. Moreover, feed points of the first vertical column of the eight vertical columns of high-band radiating elements may be staggered relative to feed points of the second vertical column of the eight vertical columns of high-band radiating elements.
A base station antenna, according to some embodiments herein, may include a reflector. The base station antenna may include first and second vertical columns of low-band radiating elements on a surface of the reflector and configured to transmit RF signals in a first frequency band. The base station antenna may include four vertical columns of high-band radiating elements on the surface of the reflector and configured to transmit RF signals in a second frequency band that is higher than the first frequency band. A horizontal distance between a feed point of the first vertical column of low-band radiating elements and a feed point of the second vertical column of low-band radiating elements may be about 225 millimeters or narrower.
In some embodiments, feed points of a first of the four vertical columns of high-band radiating elements may be staggered relative to feed points of a second of the four vertical columns of high-band radiating elements. Moreover, the feed point of the first vertical column of low-band radiating elements may be staggered relative to the feed point of the second vertical column of low-band radiating elements. The feed point of the first vertical column of low-band radiating elements may be aligned in a horizontal direction with one of the feed points of the second of the four vertical columns of high-band radiating elements.
According to some embodiments, a dipole arm of one of the low-band radiating elements may overlie one of the high-band radiating elements in a direction that is perpendicular to the surface of the reflector. Moreover, the dipole arm of the one of the low-band radiating elements may have a length equal to about half of a wavelength of the first frequency band.
In some embodiments, the first and second vertical columns of low-band radiating elements may be first and second outer columns, respectively, of low-band radiating elements. A feed point of a first outer one of the four vertical columns of high-band radiating elements may be spaced apart from a feed point of a second outer one of the four vertical columns of high-band radiating elements by the horizontal distance of about 225 millimeters or narrower. Moreover, the feed point of the first vertical column of low-band radiating elements may be aligned in a vertical direction with the feed point of the first outer one of the four vertical columns of high-band radiating elements.
According to some embodiments, the base station antenna may include a power divider that is coupled to each of the four vertical columns of high-band radiating elements. Additionally or alternatively, each of the four vertical columns of high-band radiating elements may be individually fed.
In some embodiments, the base station antenna may include a radome. The low-band radiating elements and the high-band radiating elements may be inside the radome, and the low-band radiating elements may extend forward from the surface of the reflector toward a front side of the radome. Moreover, the base station antenna may include a low-band connector on a back side of the radome that is opposite the front side. The low-band connector may be electrically coupled to one or more of the low-band radiating elements.
According to some embodiments, the low-band connector may be a 90-degree connector. Moreover, the base station antenna may include a blind mate high-band connector that is on the back side of the radome and is electrically coupled to one or more of the high-band radiating elements.
In some embodiments, the base station antenna may include first and second pluralities of high-band connection ports on the back side of the radome. The four vertical columns of high-band radiating elements may include a first array of high-band radiating elements electrically coupled to the first plurality of high-band connection ports and configured to transmit RF signals in a first sub-band of the second frequency band. Moreover, the four vertical columns of high-band radiating elements may include a second array of high-band radiating elements electrically coupled to the second plurality of high-band connection ports and configured to transmit RF signals in a second sub-band of the second frequency band that is different from the first sub-band.
A base station antenna, according to some embodiments herein, may include a reflector. The base station antenna may include first and second vertical columns of low-band radiating elements on a surface of the reflector and configured to transmit RF signals in a first frequency band. The base station antenna may include first, second, third, and fourth vertical columns of high-band radiating elements on the surface of the reflector and configured to transmit RF signals in a second frequency band that is higher than the first frequency band. The base station antenna may include a radome. The low-band radiating elements and the high-band radiating elements may be inside the radome, and the low-band radiating elements may extend forward from the surface of the reflector toward a front side of the radome. The base station antenna may include a low-band connector on a back side of the radome that is opposite the front side. The low-band connector may be electrically coupled to one or more of the low-band radiating elements. Moreover, the base station antenna may include a high-band connector that is on the back side of the radome and is electrically coupled to one or more of the high-band radiating elements.
In some embodiments, the second and third vertical columns of high-band radiating elements may be between, in a horizontal direction, the first and fourth vertical columns of high-band radiating elements. A low-band radiating element of the first vertical column of low-band radiating elements may be between, in a vertical direction that is perpendicular to the horizontal direction, first and second high-band radiating elements of the first vertical column of high-band radiating elements. A distance in the horizontal direction between a center of the low-band radiating element of the first vertical column of low-band radiating elements and a center of a low-band radiating element of the second vertical column of low-band radiating elements may be about 225 millimeters or narrower. Moreover, the low-band connector may be a 90-degree connector, and the high-band connector may be a blind mate connector.
Pursuant to embodiments of the present inventive concepts, base station antennas for wireless communication networks are provided. The enhanced-capacity capability of massive MIMO techniques for wireless communication networks makes it desirable to deploy massive MIMO antenna arrays into the existing wireless infrastructure. A frequency band that is desirable for massive MIMO operation may include all or a portion of 1695-2180 megahertz (MHz). Other frequency bands that may be considered for massive MIMO operation are in the 2490-2690 MHz and 3300-3800 MHz frequency bands. Yet wireless service providers are faced with the challenge of adding additional antennas and radio heads onto existing towers to provide massive MIMO service in these frequency bands. Some of the challenges may include the lack of availability of mounting space for an additional base station antenna array or the additional wind loading that these base station antenna arrays would add to an existing tower. Because massive MIMO antenna arrays often comprise a large number of antenna elements, often 64 to 256 elements, these arrays can be quite large in size. Additionally, wireless service providers may incur additional lease charges from tower or building owners when adding an additional base station antenna array. Moreover, in many markets, municipal zoning restrictions limit the quantity or height of base station antennas, thus limiting the ability to add massive MIMO base station antenna arrays to provide enhanced-capacity capability.
According to embodiments of the present inventive concepts, however, high-band and low-band arrays may be integrated with each other. For example, some embodiments may provide a dual-band massive MIMO beamforming antenna integrated with two low-band arrays to deliver 16T16R massive MIMO in two high bands and 4T4R MIMO in a low band simultaneously. This integrated antenna solution adds capacity in both uplink and downlink and can provide coverage enhancement for 5G networks.
A base station antenna according to some embodiments may include additional elements (low band and high band) to support multi-user MIMO, beamforming, and typically 8 or 16 streams to enable a significant boost in network capabilities. Moreover, some embodiments may substantially increase spectral efficiency to deliver more network capacity and wider coverage and take LTE network performance to, or near, 5G levels.
Additionally or alternatively, some embodiments may provide connectors on the back side of a radome of a base station antenna rather than on an end of the radome, thus reducing the length of the antenna. Moreover, the horizontal spacing (e.g., center-to-center) between feed points of low-band radiating elements may, in some embodiments, be narrower than about 225 millimeters (mm), which may provide an antenna that is at least 10% smaller than conventional antennas.
Example embodiments of the present inventive concepts will be described in greater detail with reference to the attached figures.
The base station antenna 100 includes a radome 110. In some embodiments, the base station antenna 100 further includes a top end cap 120 and/or a bottom end cap 130. For example, the radome 110, in combination with the top end cap 120, may comprise a single unit, which may be helpful for waterproofing the base station antenna 100. The bottom end cap 130 is usually a separate piece and may include a plurality of connectors 140 mounted therein. The connectors 140 are not limited, however, to being located on the bottom end cap 130. Rather, one or more of the connectors 140 may be provided on the rear (i.e., back) side of the radome 110 that is opposite the front side of the radome 110.
In some embodiments, mounting brackets 150 may be provided on the rear side of the radome 110. The mounting brackets 150 may be used to mount the base station antenna 100 onto an antenna mount that is on, for example, an antenna tower. The base station antenna 100 is typically mounted in a vertical configuration (i.e., the long side of the base station antenna 100 extends along a vertical axis L with respect to Earth).
In addition to the connectors 141, the rear side of the radome 110 may include a plurality of connectors 142 that are different from the connectors 141. For example, connectors 142-1, 142-2, 142-3, and/or 142-4 may be in respective rows on the rear side of the radome 110. Each of the rows may include, for example, eight of the connectors 142, and may be between the connectors 141 and the top end of the antenna 100. In some embodiments, an upper connector group may include the connectors 142-1 and 142-2, and a lower connector group may include the connectors 142-3 and 142-4. Moreover, the connectors 141 and/or 142 may be connectors 140 (
The vertical columns of high-band radiating elements 250 and the vertical columns of low-band radiating elements 230 may extend in a vertical direction V from a lower portion of the antenna assembly 200 to an upper portion of the antenna assembly 200. The vertical direction V may be, or may be in parallel with, the longitudinal axis L (
In some embodiments, the antenna assembly 200 may include one or more shared radiating elements 290. The shared radiating elements 290 may be provided in the center (in the horizontal direction H) of the antenna assembly 200 to advantageously maintain relative isolation between left and right columns of radiating elements (even when column-to-column spacing is narrow, as in
In some embodiments, the radiating elements 230, 250, 290 may comprise dual-polarized radiating elements that are mounted to extend forwardly in the forward direction F from the feeding board(s) 204. Moreover, the low-band radiating elements 230 may each have a generally cloverleaf or pinwheel shape in some embodiments.
The profile view also shows a row of the high-band radiating elements 250 along the horizontal direction H. The high-band row includes high-band radiating elements 250 in respective outer vertical columns 250-1C and 250-4C, and high-band radiating elements 250 in respective inner vertical columns 250-2C and 250-3C. The outer vertical columns 250-1C and 250-4C are aligned in the vertical direction V with the outer vertical columns 230-1C and 230-2C, respectively. Accordingly, the inner vertical columns 250-2C and 250-3C are between feed points 231 of the outer vertical columns 230-1C and 230-2C in the horizontal direction H.
As shown in
In some embodiments, the dipole arm 235 may have a length in (or at an angle of about 45 degrees with respect to) the horizontal direction H that is equal to about half of a wavelength at which the low-band radiating element 230 is configured to transmit. A conventional low-band radiating element, by contrast, may have a dipole length of about a full wavelength. The shorter length of the dipole arm 235 may help to provide a relatively compact antenna and may increase column isolation. Moreover, the dipole arm 235 may be a de-coupling arm having built-in invisibility at high-band frequencies to improve a radiation pattern of the high-band radiating elements 250.
The antenna assembly 200 (
As used herein, the term “outer column” (or “outer vertical column”) refers to a column that is not between, in the horizontal direction H, adjacent columns of that column type (e.g., high-band or low-band). The term “inner column” (or “inner vertical column”), by contrast, refers to a column that is between, in the horizontal direction H, adjacent columns of that column type. Also, the term “feed point” may refer to the center point of a radiating element. Moreover, the term “vertical” (or “vertically”) refers to something (e.g., a distance, axis, or column) in the vertical direction V.
Various mechanical and electronic components of the antenna 100 may be mounted in a chamber behind a back side of the reflector surface 214. The components may include, for example, phase shifters, remote electronic tilt units, mechanical linkages, a controller, diplexers, and the like. The reflector surface 214 may comprise a metallic surface that serves as a reflector and ground plane for the radiating elements 230, 250, 290 of the antenna 100. Herein, the reflector surface 214 may also be referred to as the reflector 214.
In some embodiments, the base station antenna 100 (
The low-band radiating elements 230 may be configured to be electromagnetically transparent within the 3300-3800 MHz band, and thus may not significantly impact the radiation or reception behavior of an array of the high-band radiating elements 250. Examples of radiating elements that are electromagnetically transparent to a different frequency band from that in which they are configured to transmit are discussed in Chinese Patent Application No. 201810971466.4, the disclosure of which is hereby incorporated herein by reference in its entirety.
One or more techniques for achieving electromagnetic transparency may be used for the low-band radiating elements 230. In some embodiments, a dipole arm 235 (
A distance D3 in the vertical direction V between respective feed points 251 of consecutive high-band radiating elements 250 in the vertical column 250-4C (or in one of the vertical columns 250-1C, 250-2C, or 250-3C) may be about 0.5-1 of a wavelength of a frequency band in which the high-band radiating elements 250 are configured to transmit. Moreover, a distance D4 in the horizontal direction H between a feed point 251 of the vertical column 250-3C and a feed point 251 of the adjacent vertical column 230-4C may be about 0.4-0.8 of the high-band wavelength.
By limiting the horizontal distance D2 (
As shown in
Staggered arrangements of radiating elements may result in better radiation patterns than non-staggered arrangements. Staggered arrangements, however, may provide skew in the azimuth pattern, where the skew depends upon the amount of downtilt applied to the antenna 100. This skew may be corrected by adjusting the phase as a function of downtilt, but if the radio lacks that ability, then patterns may be better at the ends of the downtilt range if a non-staggered arrangement is used.
The outer vertical columns 250-1C and 250-8C may be farther outside on the reflector 214, in the horizontal direction H, than the outer vertical columns 230-1C and 230-2C, respectively. For example, a feed point 231 of the outer vertical column 230-1C may be between a feed point 251 of the vertical column 250-2C and a feed point 251 of the vertical column 250-3C. Likewise, a feed point 231 of the outer vertical column 230-2C may be between a feed point 251 of the vertical column 250-6C and a feed point 251 of the vertical column 250-7C. Vertical columns 250-3C through 250-6C may be between the outer vertical columns 230-1C and 230-2C.
A distance D3 in the vertical direction V between respective feed points 251 of consecutive high-band radiating elements 250 in the vertical column 250-8C (or in another one of the vertical columns) may be about 0.5-1 of a wavelength of a frequency band in which the high-band radiating elements 250 are configured to transmit. Moreover, a distance D4 in the horizontal direction H between a feed point 251 of the vertical column 250-7C and a feed point 251 of the adjacent vertical column 230-8C may be about 0.4-0.8 of the high-band wavelength.
Despite the staggering of the vertical columns 250-1C through 250-8C, the vertical columns 230-1C and 230-2C may be non-staggered relative to each other, as shown in
The low-band radiating elements 230 of any of the antenna assemblies 200, 200′, 300, and 300′ according to embodiments herein may be configured to transmit and receive signals in a frequency band comprising the 617-896 MHz/694-960 MHz frequency range or a portion thereof. The high-band radiating elements 250 may be configured to transmit and receive signals in a frequency band comprising the 1400-2700 MHz/3300-4200 MHz/5100-5900 MHz frequency range or a portion thereof.
Different groups of the low-band radiating elements 230 may or may not be configured to transmit and receive signals in the same portion of a low frequency band. For example, in some embodiments, low-band radiating elements 230 in a first linear array may be configured to transmit and receive signals in the 700 MHz frequency band and low-band radiating elements 230 in a second linear array may be configured to transmit and receive signals in the 800 MHz frequency band. Alternatively, low-band radiating elements 230 in both linear arrays may be configured to transmit and receive signals in the 700 MHz (or 800 MHz) frequency band. Different groups/arrays of the high-band radiating elements 250 may similarly have any suitable configuration.
As noted above, the low-band radiating elements 230 may be arranged as two low-band linear arrays of radiating elements. Each linear array may be used to form a pair of antenna beams, namely an antenna for each of the two polarizations at which dual-polarized radiating elements are designed to transmit and receive RF signals.
The radiating elements 230, 250, 290 may be mounted on one or more feeding (or “feed”) boards 204 that couple RF signals to and from the individual radiating elements 230, 250, 290. For example, all of the radiating elements 230, 250, 290 may be mounted on the same feeding board 204. Cables may be used to connect each feeding board 204 to other components of the antenna 100, such as diplexers, phase shifters, or the like.
In some embodiments, each connector 141 (
The connectors 142-1 and 142-2 (
Because the high-band radiating elements 250 may provide a massive MIMO dual-band array with two different operating bands, two groups of the high-band radiating elements 250 may be electrically coupled to two groups of the connectors 142, respectively. The antenna 100 may thus also include a diplexer upstream of the signal transmission path.
Moreover, the connectors 142 may be blind mate connectors that are configured to electrically connect a Radio Remote Unit (RRU) to the dual-band array. The use of blind mate connectors may improve installation efficiency and system integration. As the RRU of the massive MIMO dual-band array may occupy significant space, it may be advantageous to use space-saving bent connectors (instead of blind mate connectors) as the connectors 141 for the low-band radiating elements 230 that are integrated alongside the massive MIMO dual-band array. Accordingly, the connectors 141 and the connectors 142 may be different respective types of connectors.
The arrangements of the high-band radiating elements 250 and the low-band radiating elements 230 according to embodiments of the present inventive concepts may provide a number of advantages. These advantages include integrating a large quantity of the high-band radiating elements 250 along with the low-band radiating elements 230. For example, an antenna assembly 300 or 300′ may include eight vertical columns of high-band radiating elements 250 that are on a reflector surface 214 alongside (e.g., in parallel with) two vertical columns of low-band radiating elements 230. Such an integration of a large quantity of vertical columns of high-band radiating elements 250 alongside the low-band radiating elements 230 may provide enhanced-capacity capability to an antenna 100 while fitting in a compact space.
An antenna 100 may, in some embodiments, be even more compact by using a horizontal distance between feed points 231 of different vertical columns of low-band radiating elements 230 that is about 225 mm or narrower. To further facilitate a compact design, the quantity of vertical columns of high-band radiating elements 250 alongside the tightly-spaced low-band radiating elements 230 may be four, five, six, or seven instead of eight. Though the quantity of vertical columns of high-band radiating elements 250 may be as small as four (e.g., in an antenna assembly 200 or 200′), each of these vertical columns may include a large quantity (e.g., sixteen) of high-band radiating elements 250, thus providing enhanced-capacity capability to the antenna 100.
Moreover, connectors 141 and/or 142 may be provided on the rear side of a radome 110 of an antenna 100 rather than on a bottom end cap 130, to reduce the length of the antenna 100 in the vertical direction V. For example, the connectors 141 and/or 142 may not extend in the vertical direction V to, or below, a lowermost surface of the bottom end cap 130. Accordingly, the connectors 141 and/or 142, which may be electrically coupled to of any of the antenna assemblies 200, 200′, 300, and 300′, can help the antenna 100 fit in a compact space.
The present inventive concepts have been described above with reference to the accompanying drawings. The present inventive concepts are not limited to the illustrated embodiments. Rather, these embodiments are intended to fully and completely disclose the present inventive concepts to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.
Spatially relative terms, such as “under,” “below,” “lower,” “over,” “upper,” “top,” “bottom,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the example term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Herein, the terms “attached,” “connected,” “interconnected,” “contacting,” “mounted,” and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise.
Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present inventive concepts. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
Number | Date | Country | Kind |
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201910268246.X | Apr 2019 | CN | national |
The present application is a continuation of U.S. patent application Ser. No. 16/829,148, filed Mar. 25, 2020, which claims priority to Chinese Patent Application No. 201910268246.X, filed Apr. 4, 2019, the entire content of each of which is incorporated herein by reference.
Number | Date | Country | |
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Parent | 16829148 | Mar 2020 | US |
Child | 17526488 | US |