Patent Publication Number: US-2020295799-A1

Title: Random, sequential, or simultaneous multi-beam circular antenna array and beam forming networks with up to 360° coverage

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part application of U.S. application Ser. No. 14/227,634, filed Mar. 27, 2014, which claims the benefit of U.S. Provisional Application No. 61/874,407, filed Sep. 6, 2013, the disclosures of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     Field 
     Embodiments of the invention generally relate to antennas and, more particularly, relate to random, sequential or simultaneous multi-beam antenna arrays with up to 360° antenna coverage. 
     SUMMARY 
     In accordance with one embodiment, a beam forming network system is disclosed, which includes a first beam forming network including a plurality of first ports and a plurality of second ports, in which each of the plurality of first ports is configured to be operatively coupled to one of a plurality of antenna elements; a second beam forming network including a plurality of third ports and a plurality of fourth ports, in which each of the plurality of third ports is operatively coupled to one of the plurality of second ports; and a switch sequentially coupling each of the plurality of fourth ports to a signal by sweeping the switch through a plurality of positions, thereby enabling the plurality of antenna elements to provide sequential 360° coverage. 
     The first beam forming network may be a K×N beam forming network, in which K is greater than or equal to N, and the second beam forming network may be an N×M beam forming network, in which M is less than or equal to N. At least one of the first beam forming network, second beam forming network may include at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, McFarland matrix, Davis matrix. 
     In accordance with another embodiment, a method of beam forming, is disclosed, which includes coupling each of a plurality of first ports associated with a first beam forming network operatively to one of a plurality of antenna elements; coupling each of a plurality of third ports associated with a second beam forming network operatively to one of a plurality of second ports associated with the first beam forming network; and coupling each of a plurality of fourth ports associated with the second beam forming network sequentially to a signal by sweeping a switch through a plurality of positions, thereby enabling the antenna elements to provide sequential 360° coverage. 
     The first beam forming network may be a K×N beam forming network, in which K is greater than or equal to N, and the second beam forming network may be an N×M beam forming network, in which M is less than or equal to N. At least one of the first beam forming network, second beam forming network may include at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, McFarland matrix, Davis matrix. 
     In accordance with another embodiment, a beam forming network system is disclosed, which includes at least one first beam forming network including a plurality of first ports and a plurality of second ports, in which each of the plurality of first ports is configured to be operatively coupled to one of a plurality of antenna elements; and at least one second beam forming network including a plurality of third ports and a plurality of fourth ports, in which each of the plurality of third ports being operatively coupled to one of the plurality of second ports using at least one of a first variable phase shifter, first fixed phase shifter, first attenuator, first power divider, first hybrid coupler. 
     The first beam forming network may be an MN×MN beam forming network, in which N is an integer greater than or equal to one (1) and M is an integer greater than or equal to one (1); the second beam forming network may be an N×N beam forming network, in which N is an integer greater than or equal to one (1); and the first beam forming network may be an N×(N+M) beam forming network, in which N is an integer greater than or equal to one (1)) and M is an integer greater than or equal to one (1). At least one of the first beam forming network, second beam forming network may include at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, McFarland matrix, Davis matrix. The first hybrid coupler may include at least one of a 90 degree hybrid coupler, 180 degree hybrid coupler. At least one of amplitude, phase may be controlled for sidelobe reduction in at least one of azimuth, elevation using at least one of the first variable phase shifter, first fixed phase shifter, first attenuator, first power divider, first hybrid coupler. The first beam forming network may be an N×N beam forming network, in which N is an integer greater than or equal to one (1). Each of the plurality of fourth ports may be configured to be operatively coupled to a switch operatively coupling each of the plurality of fourth ports to a signal by sweeping the switch through a plurality of positions. Each of the plurality of fourth ports may be configured to be operatively coupled to one of a plurality of transceivers operatively coupling one of the plurality of fourth ports to a signal. The plurality of antenna elements may be configured in at least one of a circle, cylinder, semi-circle, arc, line, sphere, conformal shape, curvilinear shape. The beam forming network system may include at least one third beam forming network including a plurality of fifth ports and a plurality of sixth ports, in which the plurality of fifth ports is configured to be operatively coupled to a one of the plurality of fourth ports. The beam forming network system may include at least one fourth beam forming network including a plurality of seventh ports and a plurality of eighth ports, in which each of the plurality of seventh ports is operatively coupled to one of the plurality of sixth ports using at least one of a second variable phase shifter, second fixed phase shifter, second attenuator, second power divider, second hybrid coupler. The second hybrid coupler may include at least one of a 90 degree hybrid coupler, 180 degree hybrid coupler. At least one of amplitude, phase may be controlled for sidelobe reduction in at least one of azimuth, elevation using at least one of the second variable phase shifter, second fixed phase shifter, second attenuator, second power divider, second hybrid coupler. Each of the plurality of eighth ports may be configured to be operatively coupled to a switch selectively coupling each of the plurality of eighth ports to a signal by sweeping the switch through a plurality of positions. Each of the plurality of eighth ports may be configured to be operatively coupled to one of a plurality of transceivers operatively coupling one of the plurality of eighth ports to a signal. The second beam forming network may include a power divider. 
     In accordance with another embodiment, a method of beam forming is disclosed, which includes coupling each of a plurality of first ports associated with at least one first beam forming network operatively to one of a plurality of antenna elements and coupling each of a plurality of third ports associated with at least one second beam forming network operatively to one of a plurality of second ports associated with the first beam forming network using at least one of a first variable phase shifter, first fixed phase shifter, first attenuator, first power divider, first hybrid coupler. 
     The first beam forming network may be an MN×MN beam forming network, in which N is an integer greater than or equal to one (1) and M is an integer greater than or equal to one (1); the second beam forming network may be an N×N beam forming network, in which N is an integer greater than or equal to one (1); and the first beam forming network may be an N×(N+M) beam forming network, in which N is an integer greater than or equal to one (1)) and M is an integer greater than or equal to one (1). At least one of the first beam forming network, second beam forming network may include at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, McFarland matrix, Davis matrix. The first hybrid coupler may include at least one of a 90 degree hybrid coupler, 180 degree hybrid coupler. The method may include controlling at least one of amplitude, phase for sidelobe reduction in at least one of azimuth, elevation using at least one of the first variable phase shifter, first fixed phase shifter, first attenuator, first power divider, first hybrid coupler. The first beam forming network may be an N×N beam forming network, in which N is an integer greater than or equal to one (1). The method may include coupling each of a plurality of fourth ports associated with the second beam forming network operatively to a switch operatively coupling each of the plurality of fourth ports to a signal by sweeping the switch through a plurality of positions. The method may include coupling each of a plurality of fourth ports associated with the second beam forming network operatively to one of a plurality of transceivers operatively coupling one of the plurality of fourth ports to a signal. The plurality of antenna elements may be configured in at least one of a circle, cylinder, semi-circle, arc, line, sphere, conformal shape, curvilinear shape. The method may include coupling a plurality of fifth ports associated with at least one third beam forming network operatively to one of a plurality of fourth ports associated with the second beam forming network. The method may include coupling each of a plurality of seventh ports associated with at least one fourth beam forming network operatively to one of a plurality of sixth ports associated with the at least one third beam forming network using at least one of a second variable phase shifter, second fixed phase shifter, second attenuator, second power divider, second hybrid coupler. The second hybrid coupler may include at least one of a 90 degree hybrid coupler, 180 degree hybrid coupler. The method may include controlling at least one of amplitude, phase for sidelobe reduction in at least one of azimuth, elevation using at least one of the second variable phase shifter, second fixed phase shifter, second attenuator, second power divider, second hybrid coupler. The method may include coupling a plurality of eighth ports associated with the at least one fourth beam forming network operatively to a switch selectively coupling each of the plurality of eighth ports to a signal by sweeping the switch through a plurality of positions. The method may include coupling a plurality of eighth ports associated with the at least one fourth beam forming network operatively to one of a plurality of transceivers operatively coupling one of the plurality of eighth ports to a signal. The second beam forming network may include a power divider. 
     Other embodiments of the invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of any embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are provided by way of example only and without limitation, wherein like reference numerals (when used) indicate corresponding elements throughout the several views, and wherein: 
         FIG. 1  shows a matrix fed circular array for continuous scanning; 
         FIG. 2  shows an embodiment of a circular antenna array, in which variable and fixed phase shifters shown in  FIG. 1  have been replaced with a Butler matrix; 
         FIG. 3  shows another embodiment of a circular antenna array, in which variable and fixed phase shifters shown in  FIG. 1  have been replaced with a Butler matrix; 
         FIG. 4  shows an antenna beam pattern providing 360° coverage; 
         FIG. 5  shows another embodiment of a circular antenna array, in which the Butler matrices shown in  FIG. 3  are implemented as K×N and N×M beam forming networks; 
         FIG. 6  shows another embodiment, in which an N×N beam forming network is connected to a 3N×3N beam forming network using variable phase shifters, fixed phase shifters, and three-way power dividers, which include an even or uneven power split; 
         FIG. 7  shows another embodiment, in which an N×N beam forming network is connected to a 2N×2N beam forming network using variable phase shifters, fixed phase shifters, and 180 degree hybrid couplers; 
         FIG. 8  shows another embodiment, in which an N×N beam forming network is connected to a 2N×2N beam forming network using variable phase shifters, fixed phase shifters, and 90 degree hybrid couplers; 
         FIG. 9  shows another embodiment, in which an N×N beam forming network is connected to a N×(N+M) beam forming network using one or more variable phase shifters, fixed phase shifters, and 90 degree hybrid couplers; 
         FIG. 10  shows another embodiment including a circular antenna array, N×N beam forming network, variable phase shifters, attenuators, power divider, and signal transceiver; 
         FIG. 11  shows another embodiment including a circular antenna array, first M×M beam forming network, attenuators, second M×M beam forming network, operational switch, and signal transceiver; 
         FIG. 12  shows another embodiment including a circular antenna array, first M×M beam forming network, attenuators, second M×M beam forming network, and independent signal transceivers; 
         FIG. 13  shows another embodiment including a circular antenna array, N×N beam forming network, attenuators, hybrid couplers, power dividers, and/or phase shifters, M×M beam forming network, operational switch, and signal transceiver; 
         FIG. 14  shows another embodiment including a circular antenna array, N×N beam forming network, attenuators, hybrid couplers, power dividers, and/or phase shifters, M×M beam forming network, and signal transceivers; 
         FIG. 15  shows another embodiment including a circular antenna array, N×N beam forming network, attenuators, phase shifters, and/or power dividers, M×M beam forming network, and signal transceivers; 
         FIG. 16  shows another embodiment including a cylindrical antenna array, N×N beam forming network, attenuators, hybrid couplers, power dividers, and/or phase shifters, M×M beam forming network, and signal transceivers; 
         FIG. 17  shows another embodiment including a conformal array in a single portion of a curvilinear array or in a single portion of a surface conformal array, N×N beam forming network, attenuators, hybrid couplers, power dividers, and/or phase shifters, M×M beam forming network, and signal transceivers; 
         FIG. 18  shows another embodiment including a plurality of cylindrical arrays, beam forming networks, attenuators, hybrid couplers, power dividers, and/or phase shifters, and signal transceivers; and 
         FIG. 19  shows another embodiment including a plurality of conformal arrays, beam forming networks, attenuators, hybrid couplers, power dividers, and/or phase shifters, and signal transceivers. 
     
    
    
     It is to be appreciated that elements in the figures are illustrated for simplicity and clarity. Common but well-understood elements, which are useful or necessary in a commercially feasible embodiment, are not shown in order to facilitate a less hindered view of the illustrated embodiments. 
     DETAILED DESCRIPTION 
     Embodiments disclosed herein replace variable phase shifters and fixed phase shifters with a Butler matrix beam forming network. Phase and/or amplitude tapering is used to generate narrow beams with reduced sidelobes in azimuth and/or elevation. The elements of the array may be omni and/or directional radiators in broad and/or narrow band configurations. 
       FIG. 1  shows a matrix fed circular array  10  configured for continuous scanning. The matrix fed circular antenna array  10  includes a circular antenna array  12 , a plurality of antenna elements  14 , a Butler matrix  16 , variable phase shifters  18 , fixed phase shifters  20 , and a power divider  22 . The circular antenna array  12  is coupled to output ports of the Butler matrix  16  by lines  26  of equal length. Each input port of the Butler matrix  16  is coupled to an output port of the power divider  22  through a variable phase shifter  18  and a fixed phase shifter  20 . The power divider  22  is coupled to a transceiver  24 . 
       FIG. 2  shows a first embodiment  28 , which includes a circular array  42 , a plurality of antenna elements  44 , a first Butler matrix  34 , a second Butler matrix  30 , and an optional switch  32 . The switch  32  can be an analog or a digital switch that selectively directs one or more signals to produce a beam in a certain location of 360° depending on which input of the Butler matrix is chosen. By sweeping through the positions of the switch  32 , the beam can be swept to cover a 360° footprint. 
     Each of the antenna elements  44  in the circular array  42  is coupled to an output port of the first Butler matrix  34  by lines  36  of equal length. Each input port of the first Butler matrix  34  is coupled to an output port of the second Butler matrix  30 . The second Butler matrix  30  effectively replaces the variable phase shifters  18  and fixed phase shifters  20  shown in  FIG. 1 . The optional switch  32  selectively couples input ports of the second Butler matrix  30  to a transceiver  38 , and allows a user to switch through each beam to achieve simultaneous or sequential 360° coverage. For example, if the switch  32  applies the signal from the transceiver  38  to each of the inputs of the second Butler matrix, simultaneous 360° coverage is achieved. In addition, if the switch  32  sequentially applies the signal from the transceiver  38  to each of the inputs of the second Butler matrix, sequential 360° coverage is achieved. Further, if the switch  32  applies the signal from the transceiver  38  to less than all of the inputs of the second Butler matrix, partial coverage is achieved. The use of two Butler matrices  30 ,  34  enables antenna transmissions to cover 360° simultaneously, which cannot be performed using conventional antenna systems. 
       FIG. 3  shows a second embodiment having ten ( 10 ) input ports to the second Butler matrix  30 . If the Butler matrix  30  is configured correctly, an antenna beam is provided every 36°, that is, at 0°, 36°, 72°, etc. If each of the input ports of the second Butler matrix  30  is connected to a transceiver  48 , as shown in  FIG. 3 , transmissions can occur simultaneously or sequentially at 360°. In contrast, conventional approaches, such as that shown in  FIG. 1 , include variable phase shifters  18  and fixed phase shifters  20  that can only sweep through an arc of a predetermined number of degrees in a manner that is similar to a clock&#39;s second hand that moves slowly around a central axis. However, this conventional approach provides discontinuous and non-simultaneous coverage over the predetermined arc. Since the variable phase shifters  18  and fixed phase shifters  20  require a certain amount of time to sweep through the predetermined arc, a potential target may be missed or may be allowed to pass through the predetermined arc without being detected due to latency in the phase shifters  18 ,  20 . The second embodiment  46  shown in  FIG. 3  enables connection of a multi-output transceiver  48  to couple each of the outputs of the second Butler matrix  30  to one or more transceivers  48  to provide 360° coverage. 
     Further, variable, fixed, and/or digital phase shifters are not as reliable as Butler matrices because the phase shifters are active and not passive. However, Butler matrices are passive and thus more robust and less likely to fail. In addition, Butler matrices can be made to cover a very broad band, which is larger than that of variable, fixed, and/or digital phase shifters. 
     Thus, the embodiments disclosed herein provide for random, simultaneous and/or sequential 360° antenna coverage without the necessity of scanning. Although 10 (input)×10 (output) Butler matrices are shown and described herein, it is to be understood that any configuration of Butler matrix, such as 8×8, 16×16, and the like may be used while remaining within the intended scope of the disclosure. 
       FIG. 4  shows an antenna beam pattern  50  with lobes  52  that shows an example of simultaneous 360° antenna coverage provided by the embodiment disclosed herein. In contrast, conventional approaches can only provide for an antenna pattern including fewer than each of the lobes  52 , which are swept through a predetermined arc as function of time and cannot provide for 360° coverage at any given moment in time as shown in  FIG. 4 . Any combination of beams can be used to provide the 360° coverage, such as without limitation 2, 4, 6, 8, 24, and the like beams. The combination of beams depends on the construction and phase of the Butler matrices. The crossing and/or overlap between beams can also vary depending on the design of the Butler matrices. 
       FIG. 5  shows a third embodiment  54 , which includes a circular antenna array  56 , a plurality of antenna elements  58 , a first non-square (K×N) beam forming network  60 , a second non-square (N×M) beam forming network  62 , and a plurality of transceivers  64 . In the depicted embodiment, the first and second beam forming networks are K×N and N×M beam forming networks, respectively. The circular antenna array  56  includes the plurality of antenna elements  58  and is operatively coupled to the first non-square (K×N) beam forming network  60 . The first non-square (K×N) beam forming network  60  is operatively coupled to the second non-square (N×M) beam forming network  62 , which is operatively coupled to the plurality of transceivers  64 . It should be understood that each of the beam forming networks  60 ,  62  is not limited to a Butler matrix. Other beam forming networks such as at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, McFarland matrix, and/or Davis matrix may be used as well. 
     Each of the antenna elements  58  in the circular array  56  is coupled to an output port of the K×N beam forming network  60  using K lines  66  of substantially equal length. Each input port of the K×N beam forming network  60  is coupled to an output port of the N×M beam forming network  62  by N lines  68  of substantially equal length. A combination of the K×N beam forming network  60  and the N×M beam forming network  62  effectively replaces the variable phase shifters  18  and fixed phase shifters  20  shown in  FIG. 1 . Each of the input ports of the N×M beam forming network  62  is connected to each of the plurality of transceivers  64  using M lines  70  of substantially equal length such that transmission and/or reception can occur simultaneously or sequentially at 360°. In another embodiment, each of the input ports of the N×M beam forming network  62  may be connected to a switch, such as the switch  32  shown in  FIG. 2 , such that transmission and/or reception can occur simultaneously or sequentially at 360°. These embodiments provide unique radiation patterns that are different and distinct from antenna array systems using traditional square (N×N) Butler matrices. The quantity of K lines  66  is greater than or equal to the quantity of N lines  68 , and the quantity of M lines  70  is less than or equal to the quantity of N lines  68 . 
       FIGS. 6-8  illustrate examples of multibeam antenna systems implemented using unequal or equal beamforming networks. For example,  FIG. 6  shows another embodiment, in which an N×N beam forming network  72  is operatively coupled to a MN×MN beamforming network  80 , in which M=3, using one or more variable phase shifters  76 , fixed phase shifters  78 , and/or three-way power dividers  74 , which include an even or uneven power split. M can be any integer greater than or equal to two (2). M can also be equal to one (1), which results in a retro-directive antenna. 
       FIG. 7  shows another embodiment, in which an N×N beam forming network  82  is operatively coupled to a MN×MN beam forming network  90 , in which M=2, using one or more variable phase shifters  86 , fixed phase shifters  88 , and/or 180 degree hybrid couplers  84 . M can be any integer greater than or equal to two (2). M can also be equal to one (1), which results in a retro-directive antenna. 
       FIG. 8  shows another embodiment of the disclosed subject matter, in which an N×N beam forming network  92  is operatively coupled to a MN×MN beam forming network  100 , in which M=2, using one or more variable phase shifters  96 , fixed phase shifters  98 , and/or 90 degree hybrid couplers  94 . M can be any integer greater than or equal to two (2). M can also be equal to one (1), which results in a retro-directive antenna. 
       FIG. 9  shows another embodiment of the disclosed subject matter, in which an N×N beam forming network  102  is operatively coupled to a N×(N+M) beam forming network  110 , using one or more variable phase shifters  106 , fixed phase shifters  108 , and 90 degree hybrid couplers  104 . M can be any integer greater than or equal to two (2). M can also be equal to one (1), which results in a retro-directive antenna. 
     In accordance with one or more of the disclosed embodiments, signals are able to be received from one direction and transmitted in a different direction. In addition, one or more techniques described in U.S. Pat. No. 8,170,634 may be implemented between beam forming networks in accordance with the disclosed subject matter to reduce sidelobe levels and provide power dividers with power division having various phase variations. Further, embodiments in accordance with the disclosed subject matter utilize amplitude modes as well as phase modes, wherein amplitude and/or phase is controlled and/or tapered for sidelobe reduction in azimuth and/or elevation. Yet further, it is to be noted that utilizing power division, unequal power, and/or various phases of M outputs connected to an MN×MN beam forming network enables the antenna pattern of an antenna array to yield increased gain, reduced beam width, reduced sidelobe levels, and the selection of beam crossing width to increase the signal-to-noise ratio. In accordance with one or more embodiments disclosed herein, it is to be noted that there is no constraint regarding multiple beam forming networks being required to be of the same order, type, and/or quantity of input and/or output connections, such as a requirement that both beam forming networks be 8×8 or 16×16, as shown in, for example, in  FIG. 2 . 
       FIG. 9  shows another embodiment of the disclosed subject matter, in which an N×N beam forming network  102  is operatively coupled to a N×(N+M) beam forming network  110 , in which M=7, using one or more variable phase shifters  106 , fixed phase shifters  108 , and/or 90 degree hybrid couplers  104 . M can be any integer greater than or equal to one (1). This embodiment provides beam crossovers at different values and reduces sidelobe levels, which results in a substantially improved signal-to-noise ratio that is advantageous in 5G communication applications. 
       FIG. 10  shows a circular antenna array  120 , an N×N beam forming network  118 , variable phase shifters  116 , attenuators  114 , a power divider  112 , and a signal transceiver  122 . The circular antenna array  120  is operatively coupled to output ports of the N×N beam forming network  118 . Each input port of the N×N beam forming network  118  is operatively coupled to an output port of the power divider  112  through one or more variable phase shifters  116  and/or attenuators  114 . The power divider  112  is operatively coupled to the signal transceiver  122 . In this embodiment, amplitude tapering is performed using the variable phase shifters  116  and/or attenuators  114  for sidelobe reduction in azimuth. It is to be noted that if the circular antenna array is configured vertically rather than horizontally with similar amplitude tapering, then sidelobe reduction occurs in elevation. Crossings of beams are in the region of −3 dB. 
       FIG. 11  shows a circular antenna array  124 , a first M×M beam forming network  126 , attenuators  128 , a second M×M beam forming network  130 , an operational switch  132 , and a signal transceiver  134 . The circular antenna array  124  is operatively coupled to output ports of the first M×M beam forming network  126 . Each input port of the first M×M beam forming network  126  is operatively coupled to an output port of the second M×M beam forming network  130  through one or more attenuators  128 . Each input port of the second M×M beam forming network  130  is selectively coupled to the operational switch  132 . The operational switch  132  can be an analog or a digital switch that selectively directs one or more signals to produce a beam in a certain location of 360°, depending on which input of the second M×M beam forming network  130  the signal  134  is directed to by the operational switch  134 . By sweeping through the positions of the switch  132 , the beam can be swept to cover 360°. In this embodiment, amplitude tapering for sidelobe reduction is performed in either azimuth or elevation using the attenuators  128 , depending upon whether the antenna array is configured horizontally or vertically. Crossings of beams are in the region of −3 dB. 
       FIG. 12  shows a circular antenna array  136 , a first M×M beam forming network  138 , attenuators  140 , a second M×M beam forming network  142 , and independent signal transceivers  144 . The circular antenna array  136  is operatively coupled to the first M×M beam forming network  138 , which is operatively coupled to a second M×M beam forming network  142  using one or more of the attenuators  140 . The attenuators  40  are operatively coupled to the independent signal transceivers  144 . The second beam forming network  142  is configurable to provide an antenna beam every 36°, that is, at 0°, 36°, 72°, and the like. If each of the input ports of the second beam forming network  142  is connected to a transceiver  144 , as shown in  FIG. 12 , transmission can occur simultaneously or sequentially over a 360° area. In this embodiment, amplitude tapering can be performed for sidelobe reduction in either azimuth and/or elevation using the attenuators  140 , depending upon whether the circular array is configured horizontally or vertically. Crossings of beams are in the region of −3 dB. 
       FIG. 13  shows a circular antenna array  146 , an N×N beam forming network  148 , attenuators  150 , hybrid couplers, power dividers, and/or phase shifters  151 , an M×M beam forming network  152 , an operational switch  154 , and a signal transceiver  156 . The circular antenna array  146  is operatively coupled to the N×N beam forming network  148 , which is operatively coupled to the M×M beam forming network  152  using one or more attenuators  150 , hybrid couplers, power dividers, and/or phase shifters  151 . The M×M beam forming network  152  is selectively coupled to the operational switch  154 , which is operatively coupled to the signal transceiver  156 . In this embodiment, amplitude tapering for sidelobe reduction is performed in either azimuth or elevation using the attenuators  150 , hybrid couplers, power dividers, and/or phase shifters  151 , depending upon whether the antenna array is configured horizontally or vertically. Crossings of beams may be configured using the attenuators  150 , hybrid couplers, power dividers, and/or phase shifters  151 , which also control the beam widths, at any level, such as for example −10 dB. 
       FIG. 14  shows a circular antenna array  158 , an N×N beam forming network  160 , attenuators  162 , hybrid couplers, power dividers, and/or phase shifters  163 , an M×M beam forming network  164 , and signal transceivers  166 . The circular antenna array  158  is operatively coupled to the N×N beam forming network  160 , which is operatively coupled to the M×M beam forming network  164  using one or more attenuators  162 , hybrid couplers, power dividers, and/or phase shifters  163 . The M×M beam forming network  164  is operatively coupled to the one or more of the signal transceivers  166 . In this embodiment, amplitude tapering for sidelobe reduction is performed in either azimuth or elevation using the attenuators  162 , hybrid couplers, power dividers, and/or phase shifters  163 , depending upon whether the antenna array is configured horizontally or vertically. Crossings of beams may be configured using the , attenuators  162 , hybrid couplers, power dividers, and/or phase shifters  163 , which also control the beam widths, at any level, such as for example −10 dB. 
       FIG. 15  shows a circular antenna array  168 , an N×N beam forming network  170 , attenuators  172 , phase shifters  174 , and/or power dividers  175 , an M×M beam forming network  176 , and signal transceivers  178 . The circular antenna array  168  is operatively coupled to the N×N beam forming network  170 , which is operatively coupled to the M×M beam forming network  176  using one or more attenuators  172 , phase shifters  174 , and/or power dividers  175 . The M×M beam forming network  176  is operatively coupled to one or more of the signal transceivers  178 . In this embodiment, amplitude tapering for sidelobe reduction is performed in either azimuth or elevation using the attenuators  172 , phase shifters  174 , and/or power dividers  175 , depending upon whether the antenna array is configured horizontally or vertically. Crossings of beams may be configured using the attenuators  172 , phase shifters  174 , and/or power dividers  175 , which also control the beam widths, at any level, such as for example −10 dB. 
       FIG. 16  shows a cylindrical antenna array  180 , an N×N beam forming network  182 , attenuators  184 , hybrid couplers, power dividers, and/or phase shifters  185 , an M×M beam forming network  186 , and signal transceivers  188 . The cylindrical antenna array  180  is operatively coupled to the N×N beam forming network  182 , which is operatively coupled to the M×M beam forming network  186  using one or more of the attenuators  184 , hybrid couplers, power dividers, and/or phase shifters  185 . The M×M beam forming network  186  is operatively coupled to the one or more of the signal transceivers  188 . In this embodiment, amplitude tapering for sidelobe reduction is performed in either azimuth or elevation using the attenuators  184 , hybrid couplers, power dividers, and/or phase shifters  185 , depending upon whether the antenna array is configured horizontally or vertically. Crossings of beams may be configured using the attenuators  184 , hybrid couplers, power dividers, and/or phase shifters  185 , which also control the beam widths, at any level, such as for example −10 dB. 
       FIG. 17  shows a conformal array as a single portion of a curvilinear array or as a single portion of a surface conformal array  190 , an N×N beam forming network  192 , attenuators  194 , hybrid couplers, power dividers, and/or phase shifters  195 , an M×M beam forming network  196 , and signal transceivers  198 . The conformal array  190  is operatively coupled to the N×N beam forming network  192 , which is operatively coupled to the M×M beam forming network  196  using one or more of the attenuators  194 , hybrid couplers, power dividers, and/or phase shifters  195 . The M×M beam forming network  196  is operatively coupled to one or more of the signal transceivers  198 . In this embodiment, amplitude tapering for sidelobe reduction is performed in either azimuth or elevation using the attenuators  194 , hybrid couplers, power dividers, and/or phase shifters  195 , depending upon whether the antenna array is configured horizontally or vertically. Crossings of beams may be configured using the attenuators  194 , hybrid couplers, power dividers, and/or phase shifters  195 , which also control the beam widths, at any level, such as for example −10 dB. 
       FIG. 18  shows a plurality of cylindrical arrays  200 , a plurality of beam forming network stages  202 ,  204 ,  206 ,  208 , which are connected using attenuators  210 ,  211 ,  224 , hybrid couplers, power dividers, and/or phase shifters  212 ,  213 , and signal transceivers  214 . The cylindrical arrays  200  are operatively coupled to a first stage of beam forming networks  202 , which are operatively coupled to a second stage of beam forming networks  204  using one or more attenuators  210 , hybrid couplers, power dividers, and/or phase shifters  212 . The second stage of beam forming networks  204  are operatively coupled to one or more third stage beam forming network  206 , which is operatively coupled to one or more fourth stage beam forming network  208  using one or more of the attenuators  211 , hybrid couplers, power dividers, and/or phase shifters  213 . One or more fourth stage beam forming network  208  is operatively coupled to one or more of the signal transceivers  214 . In this embodiment, amplitude tapering for sidelobe reduction is performed using the attenuators  210 ,  211 , hybrid couplers, power dividers, and/or phase shifters  212 ,  213  in azimuth and/or elevation. Crossings of beams in azimuth and/or elevation may also be configured using the attenuators  210 ,  211 , hybrid couplers, power dividers, and/or phase shifters  212 ,  213 , which also control the beam widths, at any level, such as for example −10 dB. 
       FIG. 19  shows a plurality of conformal arrays  214 , a plurality of beam forming network stages  216 ,  218 ,  220 ,  222 , which are connected using attenuators  224 ,  225 , hybrid couplers, power dividers, and/or phase shifters  226 ,  227 , and a signal transceivers  228 . The conformal arrays  214  are operatively coupled to a first stage of beam forming networks  216 , which are operatively coupled to a second stage of beam forming networks  218  using one or more attenuators  224 , hybrid couplers, power dividers, and/or phase shifters  222612 . The second stage of beam forming networks  218  are operatively coupled to one or more third stage beam forming network  220 , which is operatively coupled to one or more fourth stage beam forming network  222  using one or more of the attenuators  225 , hybrid couplers, power dividers, and/or phase shifters  227 . One or more fourth stage beam forming network  222  is operatively coupled to one or more of the signal transceivers  228 . In this embodiment, amplitude tapering for sidelobe reduction using the attenuators  224 ,  235 , hybrid couplers, power dividers, and/or phase shifters  226 ,  227  is performed in both azimuth and/or elevation. Crossings of beams in azimuth and/or elevation may also be configured using the attenuators  224 ,  225 , hybrid couplers, power dividers, and/or phase shifters  226 ,  227 , which also control the beam widths, at any level, such as for example −10 dB. 
     In accordance with one embodiment, an antenna array system that provides simultaneous transmission and/or reception with up to 360° coverage is disclosed, which includes Butler matrix beam forming networks connected together to an antenna array, which includes narrow and/or broadband elements, and multiple transmitters, receivers, or transceivers to allow for 360° transmission and/or reception. The antenna array system provides multiple beams, such as without limitation 8 or 16 beams, which can vary in beam crossing and/or overlap to provide simultaneous coverage of up to 360°. 
     In accordance with another embodiment, an antenna array system is provided, which includes a plurality of antenna elements configured in an array, a first Butler matrix operatively coupled to the plurality of antenna elements, and a second Butler matrix operatively coupled to the first Butler matrix. 
     The first Butler matrix may include a plurality of output ports and a plurality of input ports. Each of the plurality of output ports associated with the first Butler matrix may be operatively coupled to each of the plurality of antenna elements, and each of the plurality of input ports associated with the first Butler matrix may be coupled to each of a plurality of output ports associated with the second Butler matrix. The second Butler matrix may include a plurality of output ports and a plurality of input ports. Each of the plurality of output ports associated with the second Butler matrix may be operatively coupled to each of a plurality of input ports associated with the first Butler matrix, and each of the plurality of input ports associated with the second Butler matrix may be coupled to a transceiver. The antenna array system may include a switch, which can have one or multiple outputs and inputs. The second Butler matrix may include a plurality of output ports and a plurality of input ports. Each of the plurality of output ports associated with the second Butler matrix may be operatively coupled to each of a plurality of input ports associated with the first Butler matrix, each of the plurality of input ports associated with the second Butler matrix may be coupled to the output of the switch, and the input of switch may be coupled to a transceiver. The plurality of antenna elements may be configured to provide 360° coverage in response to the switch being swept through a plurality of positions. At least one of the plurality of antenna elements may include at least one of a bow tie antenna, log periodic antenna, and Vivaldi antenna. The plurality of antenna elements may be configured in at least one of a circle, cylinder semi-circle, arc, line, sphere, and/or any conformal shaped array. 
     In accordance with another embodiment, a method of providing simultaneous 360° coverage is provided, which includes configuring a plurality of antenna elements in an array, coupling a first Butler matrix operatively to the plurality of antenna elements, and coupling a second Butler matrix operatively to the first Butler matrix. 
     The method may also include coupling each of a plurality of output ports associated with the first Butler matrix operatively to each of the plurality of antenna elements, and coupling each of a plurality of input ports associated with the first Butler matrix to each of a plurality of output ports associated with the second Butler matrix. The method may include coupling each of a plurality of output ports associated with the second Butler matrix operatively to each of a plurality of input ports associated with the first Butler matrix, and coupling each of a plurality of input ports associated with the second Butler matrix to a transceiver. The method may include coupling each of a plurality of output ports associated with the second Butler matrix operatively to each of a plurality of input ports associated with the first Butler matrix, coupling each of a plurality of input ports associated with the second Butler matrix to the output of a switch, and coupling the input of switch operatively to a transceiver. The method may include configuring the plurality of antenna elements to provide 360° coverage in response to the switch being swept through a plurality of positions. At least one of the plurality of antenna elements may include at least one of a bow tie antenna, log periodic antenna, and Vivaldi antenna. The method, configuring the plurality of antenna elements as at least one of a circle, semi-circle, arc, line, sphere, and/or any conformal shape. 
     In accordance with another embodiment, an antenna array system is provided, which includes a plurality of antenna elements configured in an array, a first beam forming network operatively coupled to the plurality of antenna elements, a second beam forming network operatively coupled to the first beam forming network, and a switch. The switch includes an output and an input, and the second beam forming network includes a plurality of output ports and a plurality of input ports. Each of the plurality of output ports associated with the second beam forming network is operatively coupled to one of a plurality of input ports associated with the first beam forming network. The switch sequentially couples each of the plurality of input ports associated with the second beam forming network to a signal from a transceiver by sweeping the switch through a plurality of positions, thereby enabling the antenna to provide sequential 360° coverage. 
     The first beam forming network may be a K×N beam forming network, in which K is greater than or equal to N. The second beam forming network may be an N×M beam forming network, in which M is less than or equal to N. At least one of the first and second beam forming networks may include at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, and/or Davis matrix. 
     In accordance with another embodiment, a method of providing simultaneous 360° coverage using a multi-beam antenna array is provided, which includes configuring a plurality of antenna elements in an array, coupling a first beam forming network operatively to the plurality of antenna elements, coupling a second beam forming network operatively to the first beam forming network, coupling each of a plurality of output ports associated with the second beam forming network operatively to one of a plurality of input ports associated with the first beam forming network, coupling sequentially each of a plurality of input ports associated with the second beam forming network to a signal from a transceiver by sweeping a switch through a plurality of positions, thereby enabling the antenna to provide sequential 360° coverage. 
     The first beam forming network may be a K×N beam forming network, in which K is greater than or equal to N. The second beam forming network may be a N×M beam forming network, in which M is less than or equal to N. At least one of the first and second beam forming networks may include at least one of a Butler matrix, Blass matrix, Nolen matrix, Shelton matrix, McFarland matrix, and/or Davis matrix. 
     Although the specification describes components and functions implemented in the embodiments with reference to particular standards and protocols, the embodiment are not limited to such standards and protocols. It is to be understood that the various references throughout this disclosure made to input and output ports are not intended as a limitation on the direction of energy passing through these ports since, by the Reciprocity Theorem, energy is able to pass in either direction. Rather these references are merely intended as a convenient method of referring to various portions of the disclosed embodiments. 
     The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments are utilized and derived therefrom, such that structural and logical substitutions and changes are made without departing from the scope of this disclosure. Figures are also merely representational and are not drawn to scale. Certain proportions thereof are exaggerated, while others are decreased. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. 
     Such embodiments of the inventive subject matter are referred to herein, individually and/or collectively, by the term “embodiment” merely for convenience and without intending to limit the scope of this application to any single embodiment or inventive concept. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. 
     In the foregoing description of the embodiments, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting that the claimed embodiments have more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single embodiment. Thus, the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate example embodiment. 
     The abstract is provided to comply with 37 C.F.R. § 1.72(b), which requires an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as separately claimed subject matter. 
     Although specific example embodiments have been described, it will be evident that various modifications and changes are made to these embodiments without departing from the broader scope of the inventive subject matter described herein. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and without limitation, specific embodiments in which the subject matter are practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings herein. Other embodiments are utilized and derived therefrom, such that structural and logical substitutions and changes are made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. 
     Given the teachings of the invention provided herein, one of ordinary skill in the art will be able to contemplate other implementations and applications of the techniques of the invention. Although illustrative embodiments of the invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications are made therein by one skilled in the art without departing from the scope of the appended claims.