Patent Application
20240186711
The present invention generally relates to radio communications and, more particularly, to base station antennas for cellular communications systems.
Cellular communications systems are well known in the art. In a cellular communications system, a geographic area is divided into a series of regions that are referred to as “cells” which are served by respective base stations. The base station may include one or more antennas that are configured to provide two-way radio frequency (“RF”) communications with mobile subscribers that are within the cell served by the base station. In many cases, each cell is divided into “sectors.” In one common configuration, a hexagonally shaped cell is divided into three 120° sectors in the azimuth plane, and each sector is served by one or more base station antennas that have an azimuth Half Power Beamwidth (HPBW) of approximately 65°. Typically, the base station antennas are mounted on a tower or other raised structure, with the radiation patterns (also referred to herein as “antenna beams”) that are generated by the base station antennas directed outwardly. Base station antennas are often implemented as linear or planar phased arrays of radiating elements.
In order to accommodate the increasing volume of cellular communications, cellular operators have added cellular service in a variety of new frequency bands. In order to increase capacity without further increasing the number of base station antennas, multi-band base station antennas have been introduced which include multiple linear arrays of radiating elements. Additionally, base station antennas are now being deployed that include “beamforming” arrays of radiating elements that include multiple columns of radiating elements. The radios for these beamforming arrays may be integrated into the antenna so that the antenna may perform active beamforming (i.e., the shapes of the antenna beams generated by the antenna may be adaptively changed to improve the performance of the antenna). These beamforming arrays typically operate in higher frequency bands, such as various portions of the 3.3-5.8 GHz frequency band. Antennas having integrated radios that can adjust the amplitude and/or phase of the sub-components of an RF signal that are transmitted through individual radiating elements or small groups thereof are referred to as “active antennas.” Active antennas can generate narrowed beamwidth, high gain, antenna beams and can steer the generated antenna beams in different directions by changing the amplitudes and/or phases of the sub-components of RF signals that are transmitted through the antenna.
With the development of wireless communication technology, an integrated base station antenna including a passive module and an active antenna module with an active antenna has emerged. The passive module may include one or more passive arrays of radiating elements that are configured to generate relatively static antenna beams, such as antenna beams that are configured to cover a 120 degree sector (in the azimuth plane) of a base station antenna. The passive arrays may comprise arrays that operate under second generation (2G), third generation (3G) or fourth generation (4G) cellular standards. These passive arrays are not configured to perform active beamforming operations, although they typically have remote electronic tilt (RET) capabilities which allows the shape of the antenna beam to be changed via electromechanical means in order to change the coverage area of the antenna beam. The active antenna module may include one or more arrays of radiating elements that operate under fifth generation (or later) cellular standards. These arrays typically have individual amplitude and phase control over subsets of the radiating elements therein and perform active beamforming.
Embodiments of the present invention are directed to base station antennas with at least one grid reflector configured to allow high band radiating elements to propagate electromagnetic waves through the apertures and reflect lower band signal from lower band radiating elements in front of the grid reflector.
Embodiments of the present invention are directed to base station antennas that include at least one grid reflector with a respective array of unit cells.
The unit cells can be defined by conductive patches.
The unit cells can be defined by a pattern in sheet metal.
Embodiments of the present invention are directed to a base station antenna that includes a first frequency selective surface (FSS), a second FSS residing behind the first FSS, and an active antenna residing behind the first FSS.
The first FSS can have a first primary surface and the second FSS can have a second primary surface. The first and second primary surfaces can be parallel to each other.
The base station antenna can further include a first plurality of radiating elements residing in front of the first FSS and a second plurality of radiating elements residing behind the first FSS and behind the second FSS.
The first plurality of radiating elements can operate in a first frequency band and the second plurality of radiating elements can operate in a second frequency band.
The first plurality of radiating elements can include low band radiating elements that are configured to operate in a first frequency band, and the second plurality of radiating elements can include higher band radiating elements that are configured to operate in a second frequency band. The second frequency band can encompass higher frequencies than the first frequency band.
At least one of the first FSS and/or the second FSS can include a pattern of unit cells in sheet metal.
At least one of the first FSS and/or the second FSS can have a pattern of unit cells provided by conductive patches in or on a dielectric substrate.
The first FSS and the second FSS can both be configured to allow RF energy in the second frequency band to propagate therethrough.
The second FSS can be attached to a radome.
The second FSS can be attached to an internal facing surface of the rear radome of the base station antenna. The rear radome can cooperate with the first FSS for dielectric loading thereof.
The base station antenna can further include a primary reflector coupled to the first FSS. The primary reflector can have a first sub-length and a second sub-length. The second sub-length can have spaced apart right and left sides separated by a laterally extending opening. The first FSS can extend longitudinally and laterally across the laterally extending opening.
The base station antenna can further include a primary reflector. The first FSS can be parallel to or co-planar with the primary reflector. The first FSS can have a shorter length than the primary reflector.
The first FSS can be attached to a primary reflector.
The primary reflector and the first FSS can be defined by a monolithic unitary sheet metal body.
The first FSS can have a three-dimensional shape.
The first FSS can have laterally spaced apart right side and left side portions that extend longitudinally. The right and left side portions can define corners with orthogonal wall segments defining portions of the first FSS. Optionally, one or both wall segments can include unit cells of the grid of the first FSS.
The base station antenna can further include at least one matching layer behind the first FSS.
The base station antenna can further include at least one matching layer in front of the first FSS.
The first FSS can have a grid of unit cells configured to pass RF energy in the second frequency band and can also be configured to absorb and/or reflect at least one of RF energy in the first frequency band and RF energy in a third frequency band. The third frequency band can encompass frequencies between the first and second frequency bands.
The first FSS can include a grid of unit cells with a first subset of the unit cells that are tuned for blocking and/or reflecting RF energy in a first frequency band while allowing RF energy in a second frequency band to propagate therethrough. The first FSS can further include a second subset of the unit cells that are tuned for blocking and/or reflecting RF energy in the first frequency band and RF energy in a third frequency band. The third frequency band can include frequencies between the first and second frequency bands.
The first subset of the unit cells can be positioned at an upper portion of the base station antenna. The second subset of the unit cells can include unit cells that are positioned rearwardly of the first subset of the unit cells where some of the unit cells in the second subset of the unit cells can be to the right side of the first subset of the unit cells and other of the unit cells in the second subset of the unit cells can be to the left side of the first subset of the unit cells.
Other embodiments are directed to a base station antenna that includes a front radome and a three-dimensional frequency selective surface (FSS) positioned behind the front radome.
The FSS can have right and left side corners with first and second wall segments that are orthogonal. The first wall segment can extend laterally the second wall segment can extend in a front to back direction, rearward from the first wall segment.
The FSS can include a grid with an array of unit cells and some of the unit cells can be present on at least one of the first and second wall segments.
The right side and left side portions can reside on opposing sides of an open laterally and longitudinally extending space and the FSS can have a front surface that extends across at least part of the laterally extending space.
The base station antenna can further include a first plurality of radiating elements residing behind the FSS and a second plurality of radiating elements residing in front of the FSS.
The first plurality of radiating elements can operate in a first frequency band and the second plurality of radiating elements can operate in a second frequency band.
The first plurality of radiating elements can include high band radiating elements that operate in at least part of a 3.2-4.1 GHz frequency band. The second plurality of radiating elements can include radiating elements that operate in at least part of a lower frequency band that the high band radiating elements.
The FSS can include a pattern of unit cells in sheet metal.
The FSS can have a pattern of unit cells provided by conductive patches in or on a dielectric substrate.
The dielectric substrate/conductive patches can be provided by a flex circuit or a printed circuit board.
The FSS can be configured to allow RF energy in at least part of a 3.2-4.1 GHz frequency band to propagate therethrough.
The base station antenna can further include at least one matching layer positioned behind the FSS.
The second plurality of radiating elements can be provided in an active antenna module (also referred to as “active antenna”).
Yet other embodiments are directed to a base station antenna that includes a radome, a frequency selective surface (FSS) inside the radome, and a matching layer behind the FSS inside the radome.
The base station antenna can further include a primary reflector in the radome. The primary reflector can have right side and left side portions that reside on opposing sides of an open laterally and longitudinally extending space. The FSS can have a front surface that extends across at least part of the laterally extending space.
The base station antenna can further include a first plurality of radiating elements residing behind the FSS and a second plurality of radiating elements residing in front of the FSS.
The first plurality of radiating elements can operate in a first frequency band and the second plurality of radiating elements can operate in a second frequency band that encompasses lower frequencies than the first frequency band.
The first plurality of radiating elements can include high band radiating elements that operate in at least part of a 2.5 GHz or greater frequency band, such as in a 3.1-4.2 GHz frequency band. The second plurality of radiating elements comprise radiating elements that operate in a lower frequency band than the high band radiating elements.
The FSS can have a pattern of unit cells in sheet metal.
The FSS can have a pattern of unit cells provided by conductive patches in or on a dielectric substrate.
The FSS can be configured to allow RF energy in at least part of a 3.1-4.2 GHz frequency band to propagate therethrough.
Still other embodiments are directed to a base station antenna includes a housing with a front radome and a rear radome and an interior compartment. The base station antenna also includes a frequency selective surface (FSS) attached to a front facing surface of the rear radome.
The base station antenna can also include a first plurality of radiating elements residing in front of the FSS and a second plurality of radiating elements residing behind the FSS.
The second plurality of radiating elements can include a massive multiple input multiple output (mMIMO) array provided in an active antenna module.
The first plurality of radiating elements can operate in a first frequency band and the second plurality of radiating elements can operate in a second frequency band.
The first plurality of radiating elements can include radiating elements that operate in a first frequency band and he second plurality of radiating elements can include radiating elements that operate in a second frequency band.
The FSS can include a pattern of unit cells in sheet metal.
The FSS can include a pattern of unit cells provided by conductive patches in or on a dielectric substrate.
The FSS can be configured to allow RF energy in at least part of a 3.1-4.2 GHz frequency band to propagate therethrough.
The rear radome can cooperate with the FSS for dielectric loading thereof, optionally the FSS can be attached to the rear radome and extends in front of, closely adjacent to or abutting, an internal facing surface of the rear radome.
Yet other embodiments are directed to a base station antenna that includes: a grid reflector having an array of unit cells arranged in sheet metal; a primary reflector that merges into and/or that is coupled to the grid reflector; and a passive antenna assembly that includes plurality of linear arrays of radiating elements that extend in front of the primary reflector.
The unit cells can have a respective open center space that can be devoid of metal and that can be surrounded by a perimeter of metal.
A first of the linear array can include a first plurality of first radiating elements that extend in front of the grid reflector and a second plurality of the first radiating elements extend in front of the primary reflector.
The grid reflector and the primary reflector can be defined by a monolithic structure of sheet metal. Right and left sides of the grid reflector can merge into right and left sides of the primary reflector. The right and left sides of the primary reflector can extend longitudinally and laterally with a continuous closed surface of metal and the right and left sides of the primary reflector can each have a lateral extent that is less than a lateral extent of the grid reflector.
The primary reflector can have a solid continuous primary surface that extends across at least a major portion of a lateral extent and longitudinal extent thereof.
The base station antenna can further include a dielectric cover attached to and residing in front and/or behind the grid reflector and extending over at least a majority of the unit cells.
Neighboring unit cells of the array of unit cells can have a shared metal segment forming part of respective perimeters. The grid reflector can be configured so that neighboring unit cells have at least one shaped metal region that extends across the shared metal segment and terminates offset from a center point of a respective unit cell to thereby increase a current path for radio frequency (RF) energy.
The shaped metal region can be a box with an open center space.
The shaped metal region can be a box with a closed center space.
The perimeter of each unit cell can have a plurality of shaped metal regions that are spaced apart about the perimeter of each of the unit cells.
The shaped metal regions are shaped as rectangles.
The grid reflector can include a metal line that can form part of a perimeter of first and second unit cells that are neighboring unit cells. At least one shaped metal region with first and second parts can extend inwardly from the metal line in opposed directions into the respective first and second unit cells such that the first part of the shaped metal region resides inside the first unit cell and the second part of the shaped metal region resides inside the second unit cell.
The plurality of shaped metal regions can have a perimeter surrounding an open space that is smaller than the open space of the unit cells and that has opposing first and second ends. The first end can extend into a first unit cell and the second end can extend into a second unit cell that is immediately adjacent the first unit cell.
Each unit cell can have a metal perimeter with corners and a shaped metal region extending along a sub-length of the perimeter between two of the corners.
Each unit cell can have (at least) four shaped metal regions spaced apart about respective perimeters. Each of the four shaped metal regions can extend about a shared perimeter segment of immediately adjacent unit cells.
The base station antenna can further include a plurality of shaped metal regions spaced apart about respective perimeters. A number of shaped metal regions spaced apart about respective perimeters can be equal to a number of unit cells immediately neighboring respective unit cells.
The plurality of linear arrays can include first and second laterally spaced apart linear arrays of low band radiating elements. The base station antenna can further include a plurality of linear arrays of mid-band radiating elements extending longitudinally spaced apart from and forward of the primary reflector or extending from the grid reflector.
The base station antenna can be in combination with an active antenna module coupled to a rear of the base station antenna. The active antenna module can have an array of radiating elements facing the grid reflector. The array of radiating elements of the active antenna module are configured to propagate RF energy through the grid reflector.
The array of radiating elements of the active antenna module can have a mMIMO array of radiating elements positioned behind the grid reflector.
The grid reflector can have a lateral extent that is a sub-distance of a lateral extent of the housing of the base station antenna and can reside at an upper portion of the base station antenna, aligned with the array of adiating elements of the active antenna module.
The grid reflector can be configured to allow RF energy to pass through at one or more defined frequency range and reflect RF energy at a different frequency band
The grid reflector can be configured to reflect RF energy at a low band and pass RF energy at a higher band.
The plurality of linear arrays can include low band dipole antenna with feed stalks. The feed stalks can project forward of the grid reflector.
The active antenna module can have a radome and the radome of the active antenna module can reside adjacent to and face the rear of the base station antenna.
Additional embodiments are directed to base station antenna assemblies that include: a plurality of columns of first radiating elements configured for operating in a first operational frequency band, each column of first radiating elements comprising a plurality of first radiating elements arranged in a longitudinal direction; and a grid reflector positioned behind the plurality of columns of first radiating elements. The grid reflector is configured to reflect electromagnetic waves within the first operational frequency band.
The base station antenna can further include a plurality of columns of second radiating elements configured for operating in a second operational frequency band that is different from and does not overlap with the first operational frequency band. Each column of second radiating elements can have a plurality of second radiating elements arranged in the longitudinal direction. The grid reflector can be further configured such that electromagnetic waves within the second operational frequency band can propagate through the reflector.
The second operational frequency band can be higher than the first operational frequency band.
The grid reflector can be defined by a sheet of metal configured with an array of unit cells. The unit cells can have open center spaces devoid of metal that are surrounded by a perimeter of metal.
The base station antenna can further include a dielectric cover attached to and residing in front and/or behind the grid reflector and extending over the unit cells to thereby improve low band reflection relative to a unit cell with an interior that is open to atmosphere. Optionally, the dielectric cover can have a dielectric constant of at least one.
The grid reflector can provide a pair of neighboring unit cells with a shared metal segment forming part of respective perimeters. The grid reflector can have at least one shaped metal region that extends across the shared metal segment and can terminate inside each of the pair of neighboring unit cells, offset from a center point of each of the pair of neighboring unit cells thereof.
The shaped metal region can be a box with an open center space.
The shaped metal region can be a box with a closed center space.
The grid reflector can be configured so that a plurality of shaped metal regions are spaced apart about the perimeter of the unit cells.
The shaped metal regions can be shaped as rectangles.
The grid reflector can include a metal line that forms part of a perimeter of first and second unit cells that are immediately adjacent neighboring first and second unit cells. The grid reflector can further include at least one shaped metal region with first and second parts that extend inwardly from the metal line in opposed directions into the respective first and second unit cells such that the first part of the shaped metal region resides inside the first unit cell and the second part of the shaped metal region resides inside the second unit cell.
At least some of the plurality of shaped metal regions can have a perimeter surrounding an open space that is smaller than the open spaces of the unit cells and that has opposing first and second ends. The first end can extend into a first unit cell and the second end can extend into an immediately adjacent neighboring second unit cell.
The grid reflector can be defined by sheet metal configured with an array of unit cells, with the unit cells having open centers devoid of metal and are surrounded by metal perimeters.
The grid reflector can be defined by a monolithic body of sheet metal that provides the grid reflector and a primary reflector with a closed metal surface.
The grid reflector can have an asymmetric array of unit cells.
The grid reflector can have a greater density of unit cells at a first position relative to a density of unit cells at a second position.
The grid reflector can have unit cells with a greater lateral and/or longitudinal extent at first position relative to unit cells at a second position.
The plurality of columns of first radiating elements can be provided in a base station antenna.
The second operational frequency band is higher than the first operational frequency band.
The plurality of columns of second radiating elements can be provided by an active antenna module coupled to a rear of the base station antenna.
Still other embodiments are directed to a reflector for a base station antenna that includes: a sheet meal grid reflector with an array of unit cells; and a dielectric cover attached to and residing in front and/or behind the grid reflector and extending over at least a majority of the unit cells.
The dielectric cover can have a dielectric constant that is 1 or greater
The dielectric cover can be fiberglass.
The grid reflector can have an asymmetric array of unit cells.
The grid reflector can have a greater density of unit cells at a first position relative to a density of unit cells at a second position.
The grid reflector can have unit cells with a greater lateral and/or longitudinal extent (width and/or height) at first position relative to unit cells at a second position.
The array of unit cells can be symmetrical.
Yet other aspects are directed to a frequency selective reflector that includes a main body and a frequency selective section provided in the main body. The frequency selective section is composed of a plurality of pattern units periodically arranged in transverse and longitudinal directions, each of the pattern units has a predetermined pattern and includes a capacitor structure and an inductor structure connected in series with the capacitor structure such that the frequency selective section allows electromagnetic waves within a predetermined frequency range to pass.
The plurality of pattern units (unit cells) can be electrically connected to each other through the inductor structure.
Each of the pattern units may be in a shape of any one of a triangle, a square, a rectangle, a rhombus, a pentagon, a hexagon, a circle, and an oval and/or combinations thereof.
Each of the pattern units can include a sheet structure and a linear structure, the sheet structure can form the capacitor structure and the linear structure can form the inductor structure.
The area of the sheet structure and the length of the linear structure in the plurality of pattern units can be configured to change in a predetermined manner.
Some of the plurality of pattern units can have different configurations.
The frequency selective section/surface can be configured to allow high-frequency electromagnetic waves within the range of 2300 MHz to 4000 MHz to pass through.
The frequency selective section and the main body can be integrally formed of a metal plate.
The frequency selective section and the main body can be configured as separate components and are fixedly connected to each other to form the frequency selective reflector.
The frequency selective section and the main body can be made of different materials.
The frequency selective section can be made by punching or laser direct structuring.
The frequency selective section can include a substrate and a plurality of metal pattern units provided on the substrate.
The plurality of metal pattern units can be formed on the substrate by a selective electroplating process or a metal ink transfer printing process.
The substrate can be formed of plastic, and the metal pattern unit can be formed of any one of copper, aluminum, gold, and silver.
A base station antenna can be provided which includes a frequency selective reflector according to the present disclosure.
The base station antenna can include a passive module and/or a passive antenna assembly and an active antenna module, the active antenna module can be installed at a position corresponding to the frequency selective section of the frequency selective reflector.
According to embodiments of the present disclosure, the frequency selective section can be configured to allow electromagnetic waves emitted by the active module to pass.
It should be noted that various aspects of the present disclosure described for one embodiment may be included in other different embodiments, even though specific description is not made for the other different embodiments. In other words, all the embodiments and/or features of any embodiment may be combined in any manner and/or combination, as long as they are not contradictory to each other.
The base station antenna 100 can couple to or include at least one active antenna module 110. The term “active antenna module” is used interchangeably with “active antenna unit” and “AAU” and “active antenna” and refers to a cellular communications unit comprising radio circuitry and associated radiating elements. The radio circuitry is capable of electronically adjusting the amplitude and/or phase of the subcomponents of an RF signal that are output to different radiating elements of an array or groups thereof. The active antenna module 110 comprises the radio circuitry and the radiating elements (e.g., a multi-input-multi-output (mMIMO) beamforming antenna array) and may include other components such as filters, a calibration network, an antenna interface signal group (AISG) controller and the like. The active antenna module 110 can be provided as a single integrated unit or provided as a plurality of stackable units, including, for example, first and second sub-units such as a radio sub-unit (box) with the radio circuitry and an antenna sub-unit (box) with a multi-column array of radiating elements and the first and second sub-units stackably attach together in a front to back direction of the base station antenna 100, with the radiating elements 1195 of an antenna assembly 1190 (
As will be discussed further below, the base station antenna 100 includes an antenna assembly 190, which can be referred to as a “passive antenna assembly”. The term “passive antenna assembly” refers to an antenna assembly having arrays of radiating elements that are coupled to radios that are external to the antenna, typically remote radio heads that are mounted in close proximity to the base station antenna 100. The arrays of radiating elements included in the passive antenna assembly 190 (
The base station antenna 100 has a housing 100h. The housing 100h may be substantially rectangular with a flat rectangular cross-section. The housing 100h may be provided to define at least part of a radome 111 with at least the front side 111f configured as a dielectric cover that allows RF energy to pass through in certain frequency bands. The housing 100h may also be configured to that the rear 100r defines a rear side 111r radome opposite the front side radome 111f. Optionally, the housing 100h and/or the radome 111 can also comprise two (narrow) sidewalls 100s, 111s facing each other and extending rearwardly between the front side 111f and the rear side 111r. Typically, the top side 100t of the housing 100h may be sealed in a waterproof manner and may comprise an end cap 120 and the bottom 100b of the housing 100h may be sealed with a separate end cap 130. The front side 111f, the sidewalls 111s and typically at least part of the rear side 111r of the radome 111 are substantially transparent to radio frequency (RF) energy within the operating frequency bands of the base station antenna 100 and active antenna module 110. The radome 111 may be formed of, for example, fiberglass or plastic.
Still referring to
Referring again to
The frame 112, where used, may be configured so that a variety of different active antenna modules 110 can be mounted to the frame 112 using appropriate accessory mounting brackets 113, 114. As such, a variety of active antenna modules 110 may be interchangeably attached to the same base station antenna 100. While the frame 112 is shown by way of example, other mounting systems may be used.
In some embodiments, a plurality of active antenna modules 110 may be concurrently attached to the same base station antenna 100 at different longitudinal locations using one or more frames 112. Such active antenna modules 110 may have different dimensions, for example, different lengths and/or different widths and/or different thicknesses.
Turning now to
In some embodiments, the grid reflector 170 can be electrically and/or mechanically coupled to the primary reflector 214. In some embodiments, the grid reflector 170 can be positioned to reside between the right and left sides 214s of the primary reflector in the open medial region 14 (
The grid reflector 170 can be provided as a non-metallic substrate(s) with metal patches arranged to define an array of unit cells 171 (also interchangeably referred to as “pattern units”) or can be a metal grid and comprises an array of unit cells 171.
The non-metallic substrate can be provided as a multiple-layer printed circuit board which can be rigid, semi-rigid or a flex circuit. The non-metallic substrate can be a plastic, polymer, co-polymer with a metallized surface(s) providing conductive patches.
The grid reflector 170 can be provided as a sheet of metal, such as aluminum, with the grid shaped to form the array of unit cells 171 punched or laser formed through the sheet metal or otherwise formed.
The grid reflector 170 provides a frequency selective surface and/or substrate that is configured to allow RF energy (electromagnetic waves) to pass through at one or more first defined frequency range and that is configured to reflect RF energy at a different second frequency band. The frequency selective surface and/or substrate may be interchangeably referred to as a “FSS” herein. The reflector 170 of the base station antenna 100, can reside behind at least some antenna elements (see radiating elements 222,
The frequency selective surface and/or substrate material of the grid reflector 170 can comprise one or more of a metamaterial, a suitable RF material or even air (although air may require a more complex assembly). The term “metamaterial” refers to composite electromagnetic (EM) materials. Metamaterials may comprise sub-wavelength periodic microstructures.
The FSS material can be provided as one or more cooperating layers. The FSS material can include a substrate that has a dielectric constant in a range of about 2-4, such as about 3.7 and a thickness of about 5 mil and metal patterns formed on the dielectric substrate. The thickness can vary but thinner materials can provide lower loss.
In some embodiments, the frequency selective substrate/surface of the grid reflector 170 can be configured to act like a High Pass Filter essentially allowing low band energy to completely reflect (the FSS can act like a sheet of metal) while allowing higher band energy, for example, about 3.5 GHz or greater, to completely pass through. Thus, the frequency selective substrate/surface is transparent or invisible to the higher band energy and a suitable out of band rejection response from the FSS can be achieved. The FSS material may allow a reduction in filters or even eliminate filter requirements for looking back into the radio 1120 (
As discussed above, in some embodiments, the grid reflector 170 with the FSS may be implemented by forming the frequency selective surface on a printed circuit board, optionally a flex circuit board. In some embodiments, the grid reflector 170, for example, may be implemented as a multi-layer printed circuit board, one or more layers of which formed with a frequency selective surface configured such that electromagnetic waves within a predetermined frequency range cannot propagate through the grid reflector 170, and wherein one or more other predetermined frequency range associated with the one or more layers of the multi-layer printed circuit board is allowed to pass therethrough.
Referring to
The frequency selective section 22 may be composed of a plurality of pattern units or unit cells 171 that are periodically arranged in the transverse and longitudinal directions of the base station antenna. Each of the pattern units/unit cells 171 may have a predetermined pattern and may include a capacitor structure and an inductor structure connected in series with the capacitor structure. In addition, each of the pattern units 171 may be electrically connected to each other through the inductor structure. For example, the inductor structure in each pattern unit/unit cell 171 may be electrically connected to the inductor structure of an adjacent pattern unit.
The resonance frequency of the frequency selective section 22 may be configured by selecting or designing the pattern and size of the capacitor structure and the inductor structure of each pattern unit/unit cell 171, as well as the spacing and arrangement of a plurality of pattern units 171 such that the electromagnetic waves within a predetermined frequency range can pass through the frequency selective section 22.
Referring to
Referring to
In some embodiments according to the present disclosure, one or more, even each, unit cell/pattern unit 171 may have a different size.
In some embodiments according to the present disclosure, the grid reflector 170 can have a frequency selective section that may alternatively or also have a plurality of unit cells/pattern units 171 with different configurations.
In addition, although the pattern units in the illustrated embodiments are rectangular or substantially square, the present disclosure is not limited thereto. The unit cells/pattern unit 171 may have various shapes, such as triangle, rectangle, rhombus, pentagon, hexagon, circle, oval, and the like and combinations of different shapes for different unit cells.
In some embodiments according to the present disclosure, the frequency selective section may be configured as a slotted frequency selective section, which may be achieved by periodically opening slots of metal units on a metal plate and forming various pattern units periodically arranged as shown in
In some embodiments according to the present disclosure, the grid reflector 170 can comprise a patch type frequency selective section, which may be achieved by forming periodically arranged metal pattern units on a substrate. The plurality of metal pattern units may be formed on the substrate by a selective electroplating process or a metal ink transfer printing process. In some embodiments, the substrate may be formed of plastic, and the metal pattern unit may be formed of metal materials such as copper, aluminum, gold, and silver. In order to increase the strength of the frequency selective reflector 170, the substrate may be formed of high-strength plastic.
Turning now to
In some embodiments, the open centers 172 can be open to atmosphere/local environmental conditions. In other embodiments, the grid reflector 170 comprises a dielectric cover 271 (
The grid reflector 170 is configured to allow RF energy (electromagnetic waves) to pass through at one or more first defined frequency range and is also configured to reflect RF energy at a different second frequency range/band.
A pair 171p of neighboring unit cells 171 can share a metal (line) segment 174 defining part of each unit cells' outer perimeter 173. As shown, one unit cell 171c can be surrounded by a plurality of neighboring unit cells 171n, each neighboring unit cell 171n (shown as four neighboring unit cells 171n in this embodiment) sharing a perimeter metal line segment 174 with the center cell 171c.
Referring to
Referring to
The shaped metal regions 1173 are shown as rectangles but other shapes may be used. The rectangles, where used, can be oriented such that two long sides extend laterally, and two long sides extend longitudinally, about a perimeter 173 of respective unit cells 171.
In some embodiments, the unit cells 171 comprise perimeters 173 with corners 173c and the grid reflector 170 can be configured so that a shaped metal region 1173 extends along a sub-length of a shared metal segment 174 (of immediately adjacent, neighboring unit cells 171), shown as metal line segments, of the perimeter 173 between a pair of spaced apart corners 173c.
Referring to
The unit cells 171 of the grid reflectors 170 can have other shapes and may be symmetrical.
In some embodiments, the unit cells 171 may have asymmetric configurations.
The grid reflector 170 can be configured so that the array of unit cells 171 can be asymmetrical about one or more axis.
The metal perimeters of respective unit cells 171 can be sufficiently narrow to accommodate the angle of incidence of RF energy from radiating elements behind the grid reflector while allowing the RF energy to propagate forward while concurrently reflecting RF energy from radiating elements in front of the grid reflector 170 as the RF energy from the radiating elements behind the grid reflector 170 may propagate forward in a number of angular directions.
Referring to
The grid reflector 170 can be configured to merge into or attach to longitudinally extending right and left side 214s of (solid) surfaces of the primary reflector 214 at one or more locations, such as along longitudinally extending outer sides 170s (
When configured to allow high-band energy to pass through the grid reflector 170, thick/wide grid perimeters 173 surrounding the open spaces 172 of the unit cells 171 should be avoided to reduce blockage at off-angle scans at high band.
In some embodiments, the grid reflector 170 of the passive antenna assembly 190 can be configured to act like a High Pass Filter essentially allowing low band energy to completely reflect as the grid is formed by a sheet of metal while allowing higher band energy, for example, about 3.5 GHz or greater, to pass through, typically substantially completely pass through. Thus, the grid reflector 170 is transparent or invisible to the higher band energy and a suitable out of band rejection response can be achieved.
Turning now to
The grid reflector 170 can reside a distance in a range of ⅛ wavelength to ¼ wavelength of an operating wavelength behind the low band dipoles 222, in some embodiments. The term “operating wavelength” refers to the wavelength corresponding to the center frequency of the operating frequency band of the radiating element, e.g., a low band radiating element 222. The grid reflector 170 can reside a distance in a range of 1/10 wavelength to ½ wavelength of an operating wavelength in front of the high band radiating elements 1195, in some embodiments. By way of example, in some particular embodiments, the grid reflector 170 can reside a physical distance of 0.25 inches and 2 inches from a ground plane or reflector 1172 that is behind a mMIMO array of radiating elements 1195 of an active antenna module 110 (
In some embodiments, the ground plane or reflector 1172 of the active antenna module 110 can be electrically coupled to the grid reflector 170 and/or primary reflector 214 of the base station antenna 100, such as galvanically and/or capacitively coupled. In other embodiments, the ground plane or reflector 1172 of the active antenna module 110 is not electrically coupled to the grid reflector 170 and/or primary reflector 214.
Referring to
The antenna assembly 190 comprises multiple arrays of radiating elements, typically provided in six columns, with radiating elements that extend forwardly from the front side 170f of the reflector 170, with some columns of radiating elements continuing to extend in front of the primary reflector 214. The arrays of radiating elements of the antenna assembly 190 may comprise radiating elements 222 that are configured to operate in a first frequency band and radiating elements 232 that are configured to operate in a second frequency band. Other arrays of radiating elements may comprise radiating elements that are configured to operate in either the second frequency band or in a third frequency band. The first, second and third frequency bands may be different frequency bands (although potentially overlapping). In some embodiments, low band antenna element 222 with dipole arms can reside in front of the grid reflector 170, typically along right and left side portions 170s of the grid reflector 170 and/or primary reflector sides 214s.
As discussed above,
The grid reflector 170 and the primary reflector 214 can be monolithically formed as a unitary (sheet) metal body in some embodiments. Alternatively, the grid reflector 170 and the primary reflector 214 can be provided as separate components that are directly or indirectly attached and electrically coupled together to provide a common electrical ground. The grid reflector 170 and the primary reflector 214 can both be sheet metal of the same or different thicknesses.
In some embodiments, the grid reflector 170 can be provided by a different substrate than the primary reflector 214. In some embodiments, the grid reflector 170 can be provided as a printed circuit board with conductive patches forming the array of unit cells 171. The grid reflector 170 can be provided as a flex circuit board with conductive patches. The grid reflector 170 can be provided as a non-metallic substrate with metallized patches.
Some of the radiating elements (discussed below) of the antenna 100 may be mounted to extend forwardly from the main reflector 214, and, if dipole-based radiating elements are used, the dipole radiators of these radiating elements may be mounted approximately ¼ of a wavelength of the operating frequency for each radiating element forwardly of the main reflector 214. The main reflector 214 may serve as a reflector and as a ground plane for the radiating elements of the base station antenna 100 that are mounted thereon.
Still referring to
The low-band radiating elements 222 can be mounted to extend forwardly from the main or primary reflector 214 and the grid reflector 170 and can be mounted in two columns to form two linear arrays 220 of low-band radiating elements 222. Each low-band linear array 220 may extend along substantially the full length of the antenna 100 in some embodiments.
The low-band radiating elements 222 may be configured to transmit and receive signals in a first frequency band. In some embodiments, the first frequency band may comprise the 617-960 MHz frequency range or a portion thereof (e.g., the 617-896 MHz frequency band, the 696-960 MHz frequency band, etc.). The low-band linear arrays 220 may or may not be used to transmit and receive signals in the same portion of the first frequency band. For example, in one embodiment, the low-band radiating elements 222 in a first linear array 220 may be used to transmit and receive signals in the 700 MHz frequency band and the low-band radiating elements 222 in a second linear array 220 may be used to transmit and receive signals in the 800 MHz frequency band. In other embodiments, the low-band radiating elements 222 in both the first and second linear arrays 220-1, 220-2 may be used to transmit and receive signals in the 700 MHz (or 800 MHZ) frequency band.
The first mid-band radiating elements 232 may likewise be mounted to extend forwardly from the main reflector 214 and/or grid reflector 170 and may be mounted in columns to form linear arrays 230 of first mid-band radiating elements 232. The linear arrays 230 of mid-band radiating elements 232 may extend along the respective side edges of the grid reflector 170 and/or the main reflector 214. The first mid-band radiating elements 232 may be configured to transmit and receive signals in a second frequency band. In some embodiments, the second frequency band may comprise the 1427-2690 MHz frequency range or a portion thereof (e.g., the 1710-2200 MHz frequency band, the 2300-2690 MHz frequency band, etc.). In the depicted embodiment, the first mid-band radiating elements 232 are configured to transmit and receive signals in the lower portion of the second frequency band (e.g., some or all of the 1427-2200 MHz frequency band). The linear arrays 230 of first mid-band radiating elements 232 may be configured to transmit and receive signals in the same portion of the second frequency band or in different portions of the second frequency band.
The second mid-band radiating elements 242 can be mounted in columns to form linear arrays 240 of second mid-band radiating elements 242. The second mid-band radiating elements 242 may be configured to transmit and receive signals in the second frequency band. In the depicted embodiment, the second mid-band radiating elements 242 are configured to transmit and receive signals in an upper portion of the second frequency band (e.g., some, or all, of the 2300-2700 MHz frequency band). In the depicted embodiment, the second mid-band radiating elements 242 may have a different design than the first mid-band radiating elements 232.
The high-band radiating elements 252 and/or 1195 can be mounted in columns in the upper medial or center portion of antenna 100 to form a multi-column (e.g., four or eight column) array 250 of high-band radiating elements 252 and/or 1195. The high-band radiating elements 1195 may be configured to transmit and receive signals in a third frequency band. In some embodiments, the third frequency band may comprise the 3300-4200 MHz frequency range or a portion thereof.
In the depicted embodiment, the arrays 220 of low-band radiating elements 222, the arrays 230 of first mid-band radiating elements 232, and the arrays 240 of second mid-band radiating elements 242 are all part of the passive antenna assembly 190, while the array 250 of high-band radiating elements 1195 are part of the active antenna module 110. It will be appreciated that the types of arrays included in the passive antenna assembly 190, and/or the active antenna module 110 may be varied in other embodiments.
It will also be appreciated that the number of linear arrays of low-band, mid-band and high-band radiating elements may be varied from what is shown in the figures. For example, the number of linear arrays of each type of radiating elements may be varied from what is shown, some types of linear arrays may be omitted and/or other types of arrays may be added, the number of radiating elements per array may be varied from what is shown, and/or the arrays may be arranged differently. As one specific example, two linear arrays 240 of second mid-band radiating elements 242 may be replaced with four linear arrays of ultra-high-band radiating elements that transmit and receive signals in a 5 GHz frequency band.
At least some of the low-band and mid-band radiating elements 222, 232, 242 may each be mounted to extend forwardly of and/or from the grid reflector 170 or the main reflector 214.
Each array 220 of low-band radiating elements 222 may be used to form a pair of antenna beams, namely an antenna beam for each of the two polarizations at which the dual-polarized radiating elements are designed to transmit and receive RF signals. Likewise, each array 232 of first mid-band radiating elements 232, and each array 242 of second mid-band radiating elements 242 may be configured to form a pair of antenna beams, namely an antenna beam for each of the two polarizations at which the dual-polarized radiating elements are designed to transmit and receive RF signals. Each linear array 220, 230, 240 may be configured to provide service to a sector of a base station. For example, each linear array 220, 230, 240 may be configured to provide coverage to approximately 120° in the azimuth plane so that the base station antenna 100 may act as a sector antenna for a three-sector base station. Of course, it will be appreciated that the linear arrays may be configured to provide coverage over different azimuth beamwidths. While all of the radiating elements 222, 232, 242, 252, 1195 can be dual-polarized radiating elements in the depicted embodiments, it will be appreciated that in other embodiments some or all of the dual-polarized radiating elements may be replaced with single-polarized radiating elements. It will also be appreciated that while the radiating elements are illustrated as dipole radiating elements in the depicted embodiment, other types of radiating elements such as, for example, patch radiating elements may be used in other embodiments.
Some or all of the radiating elements 222, 232, 242, 252, 1195 may be mounted on feed boards that couple RF signals to and from the individual radiating elements 222, 232, 242, 252, 1195, with one or more radiating elements 222, 232, 242, 252, 1195 mounted on each feed board. Cables (not shown) and/or connectors may be used to connect each feed board to other components of the antenna 100 such as diplexers, phase shifters, calibration boards or the like.
RF connectors or “ports” 140 can be mounted in the bottom end cap 130 that are used to couple RF signals from external remote radio units (not shown) to the arrays 220, 230, 240 of the passive antenna assembly 190. Two RF ports can be provided for each array 220, 230, 240 namely a first RF port 140 that couples first polarization RF signals between the remote radio unit and the array 220, 230, 240 and a second RF port 140 that couples second polarization RF signals between the remote radio unit and the array 220, 230, 240. As the radiating elements 222, 232, 242 can be slant cross-dipole radiating elements, the first and second polarizations may be a −45° polarization and a +45° polarization.
A phase shifter may be connected to a respective one of the RF ports 140. The phase shifters may be implemented as, for example, wiper arc phase shifters such as the phase shifters disclosed in U.S. Pat. No. 7,907,096 to Timofeev, the disclosure of which is hereby incorporated herein in its entirety. A mechanical linkage may be coupled to a RET actuator (not shown). The RET actuator may apply a force to the mechanical linkage which in turn adjusts a moveable element on the phase shifter in order to electronically adjust the downtilt angles of antenna beams that are generated by the one or more of the low-band or mid-band linear arrays 220, 230, 240.
It should be noted that a multi-connector RF port (also referred to as a “cluster” connector) can be used as opposed to individual RF ports 140. Suitable cluster connectors are disclosed in U.S. patent application Ser. No. 16/375,530, filed Apr. 4, 2019, the entire content of which is incorporated herein by reference.
Referring to
The radiating elements 220 can be dipole elements configured to operate in some or all the 617-960 MHz frequency band. A feed circuit comprising a hook balun can be provided on the feed stalk 221. Further discussions of example antenna elements including antenna elements comprising feed stalks can be found in U.S. Provisional Patent Application Ser. Nos. 63/087,451 and 62/993,925 and/or related utility patent applications claiming priority thereto, the contents of which are hereby incorporated by reference as if recited in full herein.
Some or all of the low or mid-band radiating elements 222, 232, respectively, may be mounted on the feed boards 1200 and can couple RF signals to and from the individual radiating elements 222, 232. Cables (not shown) and/or connectors may be used to connect each feed board to other components of the base station antenna 100 such as diplexers, phase shifters, calibration boards or the like.
Turning now to
The antenna module 110 can include a radome 119 and optionally a second radome 1119. The second radome 1119 covers the first radome 119 for aesthetic purposes and can be removed at installation, in some embodiments.
The grid reflector 170 can provide a wider band pass for high band, a higher suppression for low band and a large incident angle of support over cutout reflectors.
Turning now to
The grid reflector 170 may be provided as a flex circuit that conformably attaches to the internal surface of the rear (wall) 100r of the radome 111r. A double-sided tape, adhesive, bonding material or other attachment configuration may be used to attach the grid reflector 170 to the rear radome 111r. The rear radome 111r can have a dielectric constant in a range of 1-3.
In other embodiments, referring to
Turning now to
Still referring to
The primary reflector 214 can have the spaced apart right and left side segments 214s discussed above, which can bend rearward to define back segments 214b. The grid reflector 170 can be attached to the back segments 214b and/or the internal surface 111i of the rear radome 111r. The grid reflector 170 can be provided as a multi-layer printed circuit board and/or a flex circuit.
Turning now to
Referring to
As shown in
As is also shown, the side walls 170w can extend both forwardly and rearwardly of the front surface 170f of the grid reflector 170, orthogonal thereto. The forward projection segment of the side walls 170s can be metal, metallized, or provided as a frequency selective surface/substrate.
The first grid reflector 1701 and the second grid reflector 1702 can have different primary substrates and can be tuned to reflect and propagate RF energy in the same or in different frequency bands. One of the first grid reflector 1701 or the second grid reflector 1702 can be configured as a metal grid reflector 170 and the other of the first grid reflector 1701 or the second grid reflector 1702 can be configured as a non-metallic substrate with metal patches, such as a multi-layer circuit board or a flex circuit which may improve low band reflection.
The first grid reflector 1701 can comprise unit cells 171 configured to pass RF energy in a second frequency band and absorb and/or reflect at least one of RF energy in a first frequency band and optionally also absorb and/or reflect RF energy in a third frequency band. The third frequency band can encompass frequencies between the first and second frequency bands.
Referring to
Still referring to
It is also contemplated that the base station antenna 100 can have a grid reflector 170 without any matching layers 310 by adjusting spacing of high band radiating elements in the active antenna module 110 and the low band radiating elements 222 relative to each other and the front radome 100f and/or back radome 100r using a low dielectric constant radome material, for example.
Referring to
The first subset 171a of the unit cells 171 can be positioned at an upper portion of the base station antenna 100. The second subset 171b of the unit cells 171 can include unit cells that are below and/or to right and left sides of the first subset 171a of the unit cells 171. The grid reflector 170 can include a region 171r, optionally with a third subset 171c of the unit cells 171, that can be tuned for blocking and/or reflecting RF energy in the first frequency band, the second frequency band and the third frequency band. The region 171r can be a closed metal or metallized surface and does not require unit cells and can provide increased rigidity/structural support. Some of the unit cells 171 in the second subset 171b of the unit cells 171 can be to the left side and/or right side of the first subset of the unit cells 171a. The first subset 171a of the unit cells 171 can reside behind low band radiating elements 222 and in front of high band radiating elements 1195 (e.g., a mMIMO array). The second subset 171b of the unit cells 171 can reside behind mid-band 232 radiating elements. The first frequency band can be low band, the second frequency band can be a high band frequency band, the third frequency band can be mid-band with at least some frequencies between the first and second frequencies.
The reflector 170 can be provided as a three-dimensional structure or body 170b that includes unit cells 171 that are positioned rearwardly of some of the first subset 171a of the unit cells 171.
Turning now to
The reflector 214 and/or the FSS 170 can have back segments 214b, 170b that extend rearward of the primary surface 214, 170, respectively, and reside adjacent the rear wall 100r and/or rear radome 111r.
Referring to
The first/front reflector 1701 can be at a common plane with the primary reflector 214 (a front to back position that is aligned with the primary reflector 214).
One or both of the first and second reflectors 1701, 1702 can be configured so that the grid pattern extends across an entire lateral extent thereof. In other embodiments, the grid pattern may terminate at feed boards 1200 or solid metal surfaces thereof or coupled thereto.
Referring to
As is also shown in
At least part of the side walls 170w can be provided by a metal grid or otherwise configured to provide an isolation surface/wall or an FSS, e.g., metal, metallized, or provided as a frequency selective surface/substrate.
As shown in
Embodiments of the present invention have been described above with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. It will be understood that, although the terms first, second, etc. may be used
herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (i.e., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.)
Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer or region to another element, layer or region as illustrated in the figures. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.
The term “about” used with respect to a number refers to a variation of +/−10%.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
Aspects and elements of all of the embodiments disclosed above can be combined in any way and/or combination with aspects or elements of other embodiments to provide a plurality of additional embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202122068204.7 | Aug 2021 | CN | national |
This patent application claims priority to Chinese Patent Application Serial Number 202122068204.7, filed Aug. 31, 2021, and U.S. Provisional Patent Application Ser. No. 63/254,446, filed Oct. 11, 2021, the contents of which are hereby incorporated by reference as if recited in full herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2022/080578 | 3/14/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63254446 | Oct 2021 | US |
