Patent Publication Number: US-11380991-B2

Title: Electronically steerable antenna array

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. patent application Ser. No. 16/875,655, filed May 15, 2020, which claims priority to and the benefit of U.S. provisional patent application Ser. No. 62/931,583 filed on Nov. 6, 2019. The aforementioned related patent applications are herein incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     Embodiments presented in this disclosure generally relate to antennas. More specifically, embodiments disclosed herein related to arrays of antennas that provide various controllable coverage patterns with low interference to neighboring devices. 
     BACKGROUND 
     As wireless communications options are offered in more locations, and more users take advantage of the offered wireless communications services, the demand for bandwidth and the potential for interference increases. In large venues, such as stadiums, theaters, gymnasiums, parks, etc., large expanses of open spaces can exist between the Access Points (APs) offering the wireless communication services and the stations (STA) relying on the APs for network connection. Unencumbered propagation of signals across the open spaces can lead to low cross-attenuation between cells, and exacerbates interference in the network, as network operations are limited in how different channels can be reused; placing a greater premium on free spectrum. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate typical embodiments and are therefore not to be considered limiting; other equally effective embodiments are contemplated. 
         FIGS. 1A and 1B  illustrate coverage ranges for an antenna array using wide beam arrays included therein, according to embodiments of the present disclosure. 
         FIGS. 2A-2F  illustrate coverage ranges for an antenna array using the steerable narrow beam arrays included therein, according to embodiments of the present disclosure. 
         FIGS. 3A and 3B  illustrate overlays of a first wide coverage range for a first wide beam array and the coverage ranges of a first narrow beam array, according to embodiments of the present disclosure. 
         FIGS. 4A and 4B  illustrate steering positions and offsets for the narrow beam arrays, according to embodiments of the present disclosure. 
         FIG. 5  illustrates a component layout for an antenna segment, according to embodiments of the present disclosure. 
         FIG. 6  illustrates a component layout for an antenna array, according to embodiments of the present disclosure. 
         FIG. 7  is a flowchart of a method for managing an electrically steerable antenna array, according to embodiments of the present disclosure. 
         FIG. 8  illustrates hardware of a computing device, as may be used in an AP described in the present disclosure. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially used in other embodiments without specific recitation. 
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Overview 
     One embodiment presented in this disclosure is a device, including: a plurality of antenna segments that each include: a narrow-beam antenna array, configured to produce a first beam of a first beamwidth; a wide-beam antenna array, configured to produce a second beam of a second beamwidth greater than the first beamwidth of the first beam; a switching pathway, configured to selectively activate one of the narrow-beam antenna array or the wide-beam antenna array at a given time; a first phase shifter and a second phase shifter connected between the switching pathway and the narrow-beam antenna array, configured to steer the first beam in an azimuthal plane from a first position to a second position; wherein when a given first beam of a given antenna segment of the plurality of antenna segments is steered to the first position and a different first beam of a different antenna segment of the plurality of antenna segments is steered to the first position, respective coverage ranges of the given first beam and the different first beam overlap; and wherein when the given first beam is steered to the second position and the different first beam is steered to the second position, the respective coverage ranges of the given first beam and the different first beam are spatially isolated from one another. 
     One embodiment presented in this disclosure is a system, including: a steerable and switchable antenna array configured to produce a first beam with a first coverage range and a second beam with a second coverage range; a processor; and a memory storing instructions that, when executed by the processor, enable the steerable and switchable antenna array to: select one of a first beamwidth and a second beamwidth for both the first beam and the second beam; in response to selecting the first beamwidth: switch signal inputs to narrow-beam antenna arrays included in the steerable and switchable antenna array; steer the first beam to one of a first positive offset, a first negative offset, and a first neutral position; steer the second beam to one of a second positive offset, a second negative offset, and a second neutral position; and transmit signals received from the signal inputs via the first beam and the second beam; and in response to selecting the second beamwidth: switch signal inputs to wide-beam antenna arrays included in the steerable and switchable antenna array; and transmit signals received from the signal inputs via the first beam and the second beam. 
     One embodiment presented in this disclosure is a method including: forming, by a first antenna segment, a first beam with a first coverage range, wherein forming the first beam includes: tapering a first amplitude of the first beam by supplying lower power to external elements of a first antenna array than to internal elements of the first antenna array; and steering the first beam from a first neutral position to one of a first positive offset and a first negative offset by phase shifting signals for transmission according to the first beam across columns of the first antenna array; forming, by a second antenna segment, a second beam with a second coverage range, wherein forming the second beam includes: tapering a second amplitude of the second beam by supplying lower power to external elements of a second antenna array than to internal elements of the second antenna array; and steering the second beam from a second neutral position to one of a second positive offset and a second negative offset by phase shifting signals for transmission according to the second beam across columns of the second antenna array; wherein the first coverage range and the second coverage range form a boresight pattern when the first beam is steered to the first positive offset and the second beam is steered to the second negative offset; and wherein the first coverage range and the second coverage range form an expanded linear pattern with spatial isolation between the first coverage range and the second coverage range when the first beam is steered to the first negative offset and the second beam is steered to the second positive offset. 
     EXAMPLE EMBODIMENTS 
     The present disclosure provides an electronically beamwidth switchable, beam steerable antenna array with ultra-low side lobes. The antenna can be packaged in a single weatherproofed enclosure together with AP control hardware for deployment in a variety of venues including spaces that are enclosed, semi-enclosed, or open air. The arrays are capable of switching from various beam widths and in one beam width setting are electronically steerable (i.e., the antenna remains stationary, but the direction in which the main beam is projected changes). In one embodiment, the antenna array includes two separately switchable and steerable antenna sets, which each allow for switching between a fixed wide beam and associated coverage ranges/areas and a steerable narrow beam. Each antenna set is configured to operate in a Multiple Input Multiple Output arrangement according to various communications standards. In various embodiments, a Butler matrix steers the main beam to form various coverage patterns based on the physical layout of the antennas and wireless communications needs in the venue. 
       FIGS. 1A and 1B  illustrate coverage ranges  120   a ,  120   b  for an antenna array using wide beam arrays  110   a ,  110   b  included therein, according to embodiments of the present disclosure.  FIG. 1A  provides an isometric view of the coverage ranges  120   a ,  120   b  in relation to the AP  150  and the wide beam arrays  110   a ,  110   b , while  FIG. 1B  provides an overhead view of the coverage ranges  120   a ,  120   b  (e.g., in the YX plane). When switched to use the wide beam arrays  110   a ,  110   b , an AP  150  can send and receive signals with various devices located within the respective coverage ranges  120   a ,  120   b  for those wide beam arrays  110   a ,  110   b . The wide beam arrays  110   a ,  110   b  generate respective fixed beams  130   a ,  130   b  (i.e., beams that are not electronically steerable) to generate the corresponding coverage ranges  120   a ,  120   b  centered at a given point  140   a ,  140   b  in the environment. As illustrated, the fixed beams  130   a ,  130   b  are shown at the center of the corresponding coverage ranges  120   a ,  120   b  emanating from the respective wide beam arrays  110   a ,  110   b.    
       FIGS. 2A-2F  illustrate coverage ranges  220   a - f  for an antenna array using the steerable narrow beam arrays  210   a ,  210   b  included therein, according to embodiments of the present disclosure.  FIGS. 2A, 2C, and 2E  provide isometric views of the coverage ranges  220   a - f  in relation to the AP  150  and the narrow beam arrays  210   a ,  210   b , while  FIGS. 2B, 2D, and 2F  provide overhead views of the coverage ranges  220   a - f  (e.g., in the YX plane). When switched to use the narrow beam arrays  210   a ,  210   b , an AP  150  can send and receive signals with various devices located within the respective coverage ranges  220   a - f  for those narrow beam arrays  210   a ,  210   b . The narrow beam arrays  210   a ,  210   b  generate respective steerable beams  230   a - f  (i.e., beams that are electronically steerable to different angles of transmission relative to the narrow beam arrays  210   a ,  210   b ) to generate the corresponding coverage ranges  220   a - f ,  220   b  centered at a given point  240   a - c  in the environment. As illustrated, the steerable beams  230   a - f  are shown at the center of the corresponding coverage ranges  220   a - f , emanating from the respective narrow beam arrays  210   a ,  210   b.    
     Each of  FIGS. 2A-2F  illustrate three potential steering arrangements for the second narrow beam array  210   b  in relation to one potential steering arrangement for the first narrow beam array  210   a  in a given figure. Each of the narrow beam arrays  210   a ,  210   b  are independently and separately steerable from one another, and thus in embodiments with X potential steering arrangements, there are X 2  potential overall arrangements. For example, a first and second narrow beam array  210   a ,  210   b  each with three potential steering states provide a total of nine different potential steering arrangements. 
       FIGS. 2A and 2B  illustrate the first narrow beam array  210   a  producing a narrow beam  230   a  having a first narrow coverage range  220   a  in a first position and the fourth, fifth, and sixth narrow beams  230   d - f  that the second narrow beam array  210   b  can produce with the respective fourth, fifth, and sixth narrow coverage ranges  220   d - f . The first narrow coverage range  220   a  and the fourth narrow coverage range  220   d  form a boresight coverage pattern, with significant overlap between the coverage ranges of the different beam arrays  210   a ,  210   b  (e.g., a greatest amount of overlap of the potential patterns). As the second narrow beam array  210   b  steers the narrow beams from the fourth position  230   d  to the fifth position  230   e  and from the fifth position  230   e  to the sixth position  230   f  (i.e., further away from the first narrow coverage range  220   a  than the fourth coverage range  220   d ), the overlap between the coverage ranges decreases. Although the first coverage range  220   a  is illustrated as having at least some overlap with the fifth and sixth coverage range  220   e - f  in  FIGS. 2A and 2B , in various embodiments, spatial isolation can exist between the first coverage range  220   a  and one or more of the fifth and sixth coverage ranges  220   e - f , where no overlap exists between the respective coverage ranges. 
       FIGS. 2C and 2D  illustrate the first narrow beam array  210   a  producing a narrow beam  230   b  having a second narrow coverage range  220   b  in a second position and the fourth, fifth, and sixth narrow beams  230   d - f  that the second narrow beam array  210   b  can produce with the respective fourth, fifth, and sixth narrow coverage ranges  220   d - f . The second narrow coverage range  220   b  provides less overlap and/or more spatial isolation to the fourth, fifth, and sixth coverage ranges  220   d - f  than the first narrow coverage range  220   a  does respectively. 
       FIGS. 2E and 2F  illustrate the first narrow beam array  210   a  producing a narrow beam  230   c  having a third narrow coverage range  220   c  in a third position and the fourth, fifth, and sixth narrow beams  230   d - f  that the second narrow beam array  210   b  can produce with the respective fourth, fifth, and sixth narrow coverage ranges  220   d - f . The third narrow coverage range  220   c  and the sixth narrow coverage range  220   f  form an expanded linear coverage pattern, with significant spatial isolation between the coverage ranges of the different beam arrays  210   a ,  210   b  (e.g., a greatest amount of spatial isolation of the potential patterns). The third narrow coverage range  220   c  provides less overlap and/or more spatial isolation to the fourth, fifth, and sixth coverage ranges  220   d - f  than the second narrow coverage range  220   b  does respectively. 
       FIGS. 3A and 3B  illustrate overlays of the wide coverage range  120   a ,  120   b  for a wide beam arrays  110   a ,  110   b  (not illustrated) and the narrow coverage ranges  220   a - f  of a narrow beam array  210   a ,  210   b  (not illustrated), according to embodiments of the present disclosure. 
     The first wide coverage range  120   a  and the second wide coverage range  120   b  are illustrated as encompassing all of the narrow coverage ranges  220   a - f . In some embodiments, the first wide coverage range  120   a  can encompass the associated narrow coverage ranges  220   a - c  produced in a shared antenna segment and some, but not all of the narrow coverage ranges  220   d - f  produced in a different antenna segment. Similarly, in some embodiments, the second wide coverage range  120   b  can encompass the associated narrow coverage ranges  220   d - f  produced in a shared antenna segment and some, but not all of the narrow coverage ranges  220   a - c  produced in a different antenna segment. Accordingly, an AP may switch to the wide coverage ranges  120   a ,  120   b  to serve a larger area in the environment and switch to the narrow coverage ranges  220   a - f  to serve smaller (and thus more selective) areas in the environment, for example due to a high user density in the environment all competing for limited bandwidth or user capacity in a given AP  150 . 
     Although illustrated as generally circular in cross section in  FIG. 3A , it will be appreciated that the coverage ranges  120   a ,  120   b  and  220   a - f  may have other shapes based on the number of elements in each array. For example, in  FIG. 3B , the coverage ranges  120   a ,  120   b  are shown with asymmetric (e.g., non-circular ovoid shapes), which allows for less difference in the areas served by wide and narrow beam arrays. As will also be appreciated, various embodiments can cover ranges that are more spatially isolated, less spatially isolated, have greater overlap, have less overlap, etc. between individual coverage ranges, and  FIGS. 3A and 3B  provide non-limiting examples of coverage range overlays. 
       FIGS. 4A and 4B  illustrate steering positions and offsets for the narrow beam arrays  210 , according to embodiments of the present disclosure.  FIG. 4A  shows a first set of steering positions  410   a ,  420   a , and  430   a  for a first narrow beam array  210   a  and a second set of steering positions  410   b ,  420   b , and  430   b  for a second narrow beam array  210   b  in relation to reference line  440 . The reference line  440  is perpendicular to the mounting direction of the antenna array including the narrow beam arrays  210 . For example, when the antenna array is mounted horizontally (e.g., to a ceiling, an underside of catwalk, a horizontal support or strut), the reference line  440  is aligned vertically; however, when the antenna array is mounted vertically (e.g., to a wall, a side of a catwalk, a vertical support or strut), the reference line is aligned horizontally. Accordingly, the set of steering positions are in the azimuthal plane, relative to the reference line  440 . 
     The first narrow beam array  210   a  can steer a narrow beam to a first neutral position  410   a  (also referred to as a first zero-offset position) that corresponds to the second narrow coverage range  220   b  (per  FIGS. 2C and 2D ), a first negative offset  420   a  that corresponds to the third narrow coverage range  220   c  (per  FIGS. 2E and 2F ), and a first positive offset  430   a  that corresponds to the first narrow coverage range  220   a  (per  FIGS. 2A and 2B ). Similarly, the second narrow beam array  210   b  can steer a narrow beam to a second neutral position  410   b  (also referred to as a second zero-offset position) that corresponds to the fifth narrow coverage range  220   e  (per  FIGS. 2A-2F ), a second negative offset  420   b  that corresponds to the fourth narrow coverage range  220   d  (per  FIGS. 2A-2F ), and a second positive offset  430   b  that corresponds to the sixth narrow coverage range  220   f  (per  FIGS. 2A-2F ). 
     Each of the offsets (positive and negative) adjust the angle of the respective narrow beam by an even amount from the respective neutral position, and the first positive offset  430   a  and the second negative offset  420   b  align the respective narrow beams to be parallel to the reference line  440 . The first narrow beam array  210   a  and the second narrow beam array  210   b  disposed in tilted planes relative to the reference line  440 , with the included angle of tilt set based on the angle by which the respective narrow beams are steerable. For example, when the angle of steering between the first neutral position  410   a  and the first positive offset  430   a  is R degrees, the first narrow beam array  210   a  is counter-tilted by R degrees so that the first neutral position  410   a  is −R degrees from parallel with the reference line  440  and the first positive offset  430   a  is parallel to the reference line  440 . Continuing the example, the difference from the first neutral position  410   a  to the first negative offset  420   a  is −T degrees, where T may equal R or be unequal to R in various embodiments. 
       FIG. 4B  illustrates adjustments from a reference line  440  marked at position  0 , the first neutral position  410   a  marked at position −X, and the second neutral position  410   b  marked at position +X. Each of the narrow beam arrays  210  can steer a respective beam by a positive increment or a negative increment from the neutral position  410   a / 410   b  to align the beam in parallel to the reference line  440  (e.g., at position  0 ) or at a position ±Y from the reference line  440 . The angles of steering  450   a - d  between the different positions are shown such that the first angle of steering  450   a  is equal to the fourth angle of steering  450   d  (e.g., the first neutral position  410   a  and the first negative offset  420   a  and the second neutral position  410   b  and the second positive offset  430   b ) and the second angle of steering  450   b  is equal to the third angle of steering  450   c  (e.g., the first neutral position  410   a  and the first positive offset  430   a  and the second neutral position  410   b  and the second negative offset  420   b ). In some embodiments, all of the angles of steering  450   a - d  are equal to one another, while in others, the two sets of steering angles  450   a / 450   d  and  450   b / 450   c  are distinct from one another. As will be appreciated, depending on the topography or presence of walls or other obstructions in the environment (and whether the antenna array is mounted vertically, horizontally, or some intermediate angle) steering the beams by equal angles in opposite direction may not result in an even translation of the coverage area. Additionally, portions of the coverage area positioned at different distances from the antenna array may experience different signal strengths. 
       FIG. 5  illustrates a component layout for an antenna segment  500 , according to embodiments of the present disclosure. Each antenna segment  500  is configured to operate either a narrow-beam antenna array  510  and a wide-beam antenna array  550  (at a given time. The narrow-beam antenna array  510  provides an N×N array of antenna elements, whereas the wide-beam antenna array  550  provides a 1×M array of antenna elements. The number of elements (e.g., the individual signaling elements making up the antenna arrays) in an array determines the beamwidth in azimuth and elevation. The layout of the narrow-beam patch  510  provides an (N−2)×(N−2) subset of inner antenna elements  512 , which are surrounded by a subset of outer antenna elements (i.e., those antenna elements included in the narrow-beam antenna array  510  that are not neighbored by at least four antennas). 
     The narrow-beam antenna array  510  and the wide-beam antenna array  550  are dual polarized antenna arrays. By being dual polarized, two different radio paths can use the same array at the same time. One path is connected to a vertical polarization feed, while the other is connected to a horizontal polarization feed, essentially providing two antenna arrays with one set of elements. 
     Signals are routed to/from the narrow-beam antenna array  510  or the wide-beam antenna array  550  via a switching pathway. The switching pathway includes several switches  530   a - b  and  540   a - b  that route signals to/from the activated antenna array. Base switches  540   a - b  determine whether the signals are routed to/from the narrow-beam array  510  or the wide-beam antenna array  550 , whereas intermediary switches  530   a - b  route the signals to/from the phase shifters  520   a - b  connected to the narrow-beam antenna array  510 . Although illustrated with one arrangement of switching components, it will be appreciated that various other arrangements of switching components (including cascaded 2:1 switches) can be used to link the antenna arrays to various signaling sources. 
     The low side lobes formed through aggressively tapering the narrow beam prevent APs in the same frequencies from detecting one another&#39;s transmissions, even when mounted in close proximity to one another (e.g., within 50 feet). In some embodiments, the side lobes have an amplitude of −30 dB relative to the main lobes of the narrow beam. In various embodiments, unequal power dividers and attenuators are used to provide lower powered signals to the outer antenna elements of the narrow-beam antenna array  510  than the inner antenna elements, thereby reducing the power of the side lobes relative to a main lobe. Due to the control of the side lobe amplitude, the antenna segment  500  (and any antenna array including the antenna segment  500 ) can omit bandpass filters  560   a - b  that are typically used to increase isolation between co-located radios within an AP, although in some embodiments the bandpass filters can be retained to increase co-located radio isolation. 
     A pair of phase shifters  520   a - b  is connected to each feed of the dual-polarized narrow-beam antenna array  510 , which allows for each polarization of the beam to be steered. These positions can include a neutral position, where no steering is applied, a positive offset from the neutral position in a first direction, and a negative offset from the neutral position in a second direction opposite to the first direction. In various aspects, the phase shifters  520   a - b  are Butler matrices, but other switched phase feed networks can be used as phase shifters  520   a - b  to steer the beams in discrete increments while maintaining minimal side lobes. wherein the first phase shifter  520   a  steers the first beam for the vertical polarization by phase shifting the first signal across columns of the narrow-beam antenna array  510  and wherein the second phase shifter  520   b  steers the first beam for the horizontal polarization by phase shifting the second signal across columns of the narrow-beam antenna array  510 . 
     In various embodiments, the phase shifters  520   a - b  steer the narrow beam by creating relative phase differences in the columns of the narrow-beam array  510 . For example, when steering to a positive offset, if the first column  511   a  has a phase of A, the second column  511   b  would have a phase of A+B where B is a fixed phase difference determined to create the desired degrees of steering, the third column  511   c  would have a phase of A+(2*B), and the fourth column  511   d  would have a phase of A+(3*B). To steer to a negative offset, if the first column  511   a  has a phase of A, the second column  511   b  would have a phase of A-B where B a fixed phase difference determined to create the desired degrees of steering, the third column  511   c  would have a phase of A−(2*B), and the fourth column  511   d  would have a phase of A−(3*B). To remain at the neutral or zero-offset position, the phases across the columns  511   a - d  are all equal. 
     The wide-beam antenna array  550  produces a fixed position beam (e.g., the beams  130   a ,  130   b  discussed in  FIGS. 1A and 1B ), whereas the narrow-beam antenna array  510  produces an electronically steerable beam (e.g., the beams  230   a - f  discussed in  FIGS. 2A-2F ). The narrow-beam antenna array  510  produces a beam of a first beamwidth, which is less than the beamwidth of the beam produced by the wide-beam antenna array  550 . In various embodiments, the beamwidth of the beam produces by the wide-beam antenna array  550  includes or encompasses all of the coverage ranges of the beam produced by the narrow-beam antenna array  510  steered to any of the potential positions thereof. 
       FIG. 6  illustrates a component layout for an antenna array  600 , according to embodiments of the present disclosure. The antenna array  600  includes four instances of an antenna segment  500   a - d  as described in relation to  FIG. 5  and an interface  610  acting as a signal source for signals to transmit via the antenna segments  500   a - d , and may be used as a steerable and switchable antenna array for various APs in venues in which available bandwidth is at a premium. In various embodiments, two or more radios are connected to the antenna segments  500   a - d  (and/or alternative antennas) via the interface  610 . 
     In various embodiments, additional alternative antennas can also be connected (via one or more switches) to various ports of the interface  610  to allow for different frequencies, communication standards, or beam patterns to be used in the antenna array  600 . For example, the antenna segments  500   a - d  can operate in a first frequency bandwidth (e.g., 5 GHz) from all of the radios sending signals via the ports of the interface  610  (e.g., ports ABCD and EFGH), but additional antennas (not illustrated) connected to a subset of the ports (e.g., ports EGHG) can operate in a second frequency bandwidth (e.g., 2.4 GHz). 
     Using four instances of the antenna array  600 , an AP is configured to operate in a dual 4×4 MIMO mode with no mutual interference between radios. Accordingly, due to the beam shaping and tapering provided by the individual antenna segments  500   a - d  (e.g., precise antenna pattern with low side lobe levels), the antenna array  600  allows for high-channel reuse in high-density applications where several APs are deployed with corresponding instances of the antenna array  600 . Switchable beam directions allow flexibility in aligning cells in the same or adjoining coverage areas for the different APs so that several APs can be grouped closely together (e.g., within 50 feet of one another). 
       FIG. 7  is a flowchart of a method  700  for managing an electrically steerable antenna array, according to embodiments of the present disclosure. Method  700  can be performed independently by each antenna set in the antenna array so that each beam is independently switched to/from a narrow or wide setting and is independently steered to various positions when in the narrow setting. As will be appreciated, elements of method  700  are performed intrinsically by using the antenna array disclosed herein, and one or more blocks may be performed substantially in parallel or at the same time as other blocks of method  700 , and method  700  may periodically cycle or repeat as the antenna array is controlled to update how the coverage ranges are generated. 
     At block  710 , the antenna array switches operational modes between one of a wide coverage mode or a narrow coverage mode. An AP connected to the antenna array can signal which operational mode to switch to based off of the coverage needs of the various stations in communication with the AP, signal propagation characteristics of the environment, and the number of stations attempting to communicate with the AP, among other factors. When the antenna array switches to the narrow coverage mode, the method  700  proceeds to block  720 . When the antenna array switches to the wide coverage mode, the method  700  proceeds to block  760 . 
     At block  720 , the antenna array forms a narrow beam with a narrow coverage range by activating a narrow beam array. The narrow beam array can send and receive signals via various polarizations to reuse the available hardware and available spectrum. When forming a narrow beam, the antenna array tapers the amplitude of the narrow beam (per block  730 ) by supplying lower power to the external elements of the narrow beam array than to the internal elements of the narrow beam array, and determines where to steer the narrow beam. In various embodiments, the difference in power supplied to the internal and external elements of the narrow beam array produces a beam with side lobes with a power level −30 dB relative to the power level a main beam, which allows for several APs using instances of the antenna array to be placed close to one another (e.g., within 50 feet of one another) and use the same channel without interfering with one another or causing cross-talk between the APs. 
     At block  740 , the antenna array steers the narrow beam to a desired offset. In various embodiments, the antenna array can steer the narrow beam to one of three positions by one of: leaving the narrow beam in a neutral position, applying a positive phase shift to the signals across the columns of the narrow beam array to steer the narrow beam to a positive offset, or apply a negative phase shift to the signals across the columns of the narrow beam array to steer the narrow beam to a negative offset. 
     When two narrow beam arrays are both in the narrow mode, the antenna array can provide several different coverage patterns, such as those illustrated in  FIGS. 2A-2F . For example, when a first coverage range is steered to a first positive offset and a second coverage range is steered to a second negative offset, the antenna array produces a boresight pattern, where each of the coverage ranges overlap to a greatest extent possible given the steering options. In contrast, when a first coverage range is steered to a first negative offset and a second coverage range is steered to a second positive offset, the antenna array produces an expanded linear pattern with a greatest spatial isolation between the two coverage ranges given the steering options. The antenna array can produce other coverage patterns with intermediary levels of overlap/spatial isolation according to the wireless communications needs of the stations served by the associated AP. 
     At block  750 , the antenna array forms a wide beam with a wide coverage range by activating a wide beam array. The wide beam array is neither tapered nor steered, and provides a wide coverage range that encompasses ranges of the narrow beams at each of the steered positions. 
     Once the beam (narrow or wide) is formed, method  700  proceeds to block  760 , where the antenna array sends and receives signals according via the formed beam in the corresponding coverage range. Method  700  may then conclude or restart at block  710  when the beam is reformed (e.g., switched from narrow to wide, switched from wide to narrow, steered to a different offset, etc.). 
       FIG. 8  illustrates hardware of a computing device  800 , as may be used in an AP  150  described in the present disclosure. The computing device  800  includes a processor  810 , a memory  820 , and communication interfaces  830 . The processor  810  may be any processing element capable of performing the functions described herein. The processor  810  represents a single processor, multiple processors, a processor with multiple cores, and combinations thereof. The communication interfaces  830  facilitate communications between the computing device  800  and other devices, such as the interface  630 . The memory  820  may be either volatile or non-volatile memory and may include RAM, flash, cache, disk drives, and other computer readable memory storage devices. Although shown as a single entity, the memory  820  may be divided into different memory storage elements such as RAM and one or more hard disk drives. 
     As shown, the memory  820  includes various instructions that are executable by the processor  810  to provide an operating system  821  to manage various functions of the computing device  800  and one or more applications  822  to provide various functionalities to users of the computing device  800 , which include one or more of the functions and functionalities described in the present disclosure. 
     In the current disclosure, reference is made to various embodiments. However, the scope of the present disclosure is not limited to specific described embodiments. Instead, any combination of the described features and elements, whether related to different embodiments or not, is contemplated to implement and practice contemplated embodiments. Additionally, when elements of the embodiments are described in the form of “at least one of A and B,” it will be understood that embodiments including element A exclusively, including element B exclusively, and including element A and B are each contemplated. Furthermore, although some embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the scope of the present disclosure. Thus, the aspects, features, embodiments and advantages disclosed herein are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the invention” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). 
     As will be appreciated by one skilled in the art, the embodiments disclosed herein may be embodied as a system, method or computer program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, embodiments may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. 
     Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for embodiments of the present disclosure may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
     Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments presented in this disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the block(s) of the flowchart illustrations and/or block diagrams. 
     These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other device to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the block(s) of the flowchart illustrations and/or block diagrams. 
     The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process such that the instructions which execute on the computer, other programmable data processing apparatus, or other device provide processes for implementing the functions/acts specified in the block(s) of the flowchart illustrations and/or block diagrams. 
     The flowchart illustrations and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments. In this regard, each block in the flowchart illustrations or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
     In view of the foregoing, the scope of the present disclosure is determined by the claims that follow.