Patent Publication Number: US-2021194148-A1

Title: Spherical space feed for antenna array systems and methods

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/734,159, filed Jan. 3, 2020, which is incorporated herein by reference in its entirety. Said U.S. application Ser. No. 16/734,159 is a continuation of U.S. application Ser. No. 15/674,475, filed Aug. 10, 2017, now issued as U.S. Pat. No. 10,541,476, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Embodiments of inventive concepts disclosed herein relate the field of antenna arrays including but not limited to, phased array antenna systems or electronically scanned array (ESA) antenna systems, such as active electronically scanned array (AESA) antenna systems having space feeds. 
     Antenna arrays can provide improved antenna performance by allowing control of phase (or relative time delay) and relative amplitude of the signal associated with each antenna element in an antenna array. By adjusting signal phase and/or relative amplitude of separate antenna elements, information redundancy in signals associated with distinct antenna elements can be used to form a desired beam signal. Space feeds can be used to provide a radiative wireless connection between a single feed point radiator and each channel or antenna element of an AESA. Conventional space feeds can be used to achieve lower radiated side lobe levels from an antenna array at the expense of aperture gain and feed spillover loss (by extension, illumination efficiency). 
     SUMMARY 
     In one aspect, embodiments of the inventive concepts disclosed herein are directed to antenna array system including a feed antenna and circuit boards. Each circuit board has pickup antenna elements disposed on a curved edge portion of a first edge of the circuit board, radiating elements disposed on a second edge portion of the circuit board, and transmit receive modules disposed between the pickup elements and the radiating elements on the circuit board. 
     In some embodiments, each transmit/receive module can include one or more amplifiers and one or more phase-shifters configured to control amplitudes and phases, respectively, of signals associated with an array of antenna elements of a corresponding metallic structure coupled to a printed circuit board. In some embodiments, the array of antenna elements can have a frequency bandwidth that includes at least the frequency range between 18 GHz and 60 GHz. 
     In another aspect, embodiments of the inventive concepts disclosed herein are directed to method of manufacturing an array antenna. The method includes providing circuit board cards having first metallization layer traces configured as pickup antennas and second metallization layer traces configured as radiation antennas, and providing a feed antenna proximate a first edge of the cards. The first edge is associated with the pickup antennas, and the pickup antennas are arranged in a curved fashion. 
     In some embodiments, the antenna elements in each sheet metal structure are physically formed using laser cutting or chemical etching. In some embodiments, the one or more alignment structures can include the at least one electromagnetic shielding structure. In some embodiments, each printed circuit board includes one or more amplifiers and one or more phase-shifters (or time delay elements) configured to control amplitudes and phases (or delay), respectively, of signals associated with antenna elements. 
     In another aspect, embodiments of the inventive concepts disclosed herein are directed to a spherical space feed for an antenna array assembly. The spherical space feed includes at least one circuit board comprising pickup antenna elements disposed in a curved fashion at a first edge of the circuit board, radiating antenna elements disposed on a second edge of the circuit board, and transmit receive modules disposed between the pickup antenna elements and the radiating antenna elements on the circuit board. The first edge is opposite the second edge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the inventive concepts disclosed herein may be better understood when consideration is given to the following detailed description thereof. Such description makes reference to the included drawings, which are not necessarily to scale, and in which some features may be exaggerated and some features may be omitted or maybe represented schematically in the interest of clarity. Like reference numerals in the drawings may represent and refer to the same or similar element, feature, or function. In the drawings: 
         FIG. 1  is a schematic top view planar drawing of an AESA assembly including cards with pickup antennas and radiating antennas according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 2  is a schematic front view planar drawing of one of the cards illustrated in  FIG. 1  according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 3  is a schematic top view planar drawing of one of the cards for use in a horizontally polarized (HP) cylindrical AESA assembly where the cards are provided at varying angles about an X-axis according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 4  is a schematic top view planar drawing of one of the cards for use in a vertically polarized (VP) cylindrical AESA assembly where the cards are provided at varying angles about a Z-axis according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 5  is a schematic top view planar drawing of one of the cards for use in an HP hemispherical AESA assembly where the cards are provided at varying angles about an X-axis according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 6  is a schematic top view planar drawing of one of the cards for use in a VP hemispherical AESA assembly where the cards are provided at varying angles about a Z-axis according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 7  is a schematic top view planar drawing of a dual linear polarization cylindrical AESA assembly according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 8  is a schematic top view planar drawing of the dual linear polarization cylindrical AESA assembly illustrated in  FIG. 7  according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 9  is a schematic top view planar drawing of one of the cards of a first type polarization for use in the dual linear polarization cylindrical AESA assembly illustrated in  FIG. 7  according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 10  is a schematic side view planar drawing of one of the cards of a second type polarization for use in the dual linear polarization cylindrical AESA assembly illustrated in  FIG. 7  according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 11  is a schematic top view planar drawing of a dual linear polarization hemispherical AESA assembly according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 12  is a schematic top view planar drawing of one of the cards of a first type polarization for use in the dual linear polarization hemispherical AESA assembly illustrated in  FIG. 11  according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 13  is a schematic side view planar drawing of one of the cards of a second type polarization for use in the dual linear polarization hemispherical AESA assembly illustrated in  FIG. 11  according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 14  is a schematic top view planar drawing of one example (using Vivaldi antenna elements) of the cards for use in a planar array spherical feed assembly according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 15  is a schematic perspective view drawing of planar array spherical space feed integrated into a planar AESA assembly according to exemplary aspects of the inventive concepts disclosed herein; 
         FIG. 16  is a schematic perspective view drawing of a multifaceted space feed assembly according to exemplary aspects of the inventive concepts disclosed herein; and 
         FIG. 17  is a schematic perspective view drawing of examples of hemispherical coverage arrays according to exemplary aspects of the inventive concepts disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     Before describing in detail embodiments of the inventive concepts disclosed herein, it should be observed that the inventive concepts disclosed herein include, but are not limited to a novel structural combination of components and circuits, and not to the particular detailed configurations thereof. Accordingly, the structure, methods, functions, control and arrangement of components and circuits have, for the most part, been illustrated in the drawings by readily understandable block representations and schematic diagrams, in order not to obscure the disclosure with structural details which will be readily apparent to those skilled in the art, having the benefit of the description herein. Further, the inventive concepts disclosed herein are not limited to the particular embodiments depicted in the diagrams provided in this disclosure, but should be construed in accordance with the language in the claims. 
     According to certain aspects of inventive concepts, systems and methods provide a space feed for an antenna assembly (e.g., an AESA assembly or a Vivaldi assembly). Space feeds provide a wireless interconnect between a single point feed radiator and each channel of the AESA in some embodiments. Stripline and microstrip connectorized corporate feed manifolds can have high loss at millimeter frequencies. Such losses severely complicate AESA design for electrically large arrays, particularly affecting signal to noise ratio (SNR) without large amounts of amplification. Large amounts of amplification increases size, weight, cost and power and require increased AESA thermal management. Further, at high frequencies (e.g., 20-44 gigahertz), the connector size can prevent appropriate spacing (at half wavelengths apart) for the array to perform adequately as a scanning array structure. 
     In some embodiments, a primary AESA aperture is configured as a “sampled lens” with receive pickup antenna elements that each feed a respective transmit/receive module TRM and a respective primary radiating element of the AESA. The pickup and primary radiating elements are identical in some embodiments. In some embodiments, the pickup and primary radiating elements are not identical. The stencil antenna technology described in U.S. patent application Ser. No. 15/048,969 incorporated herein by reference in its entirety is used to provide a lens array compatible with the space feed technology as described herein. 
     In some embodiments, systems and methods provide spherical phased array space feeds using transmit-receive modules (TRMs) as described in one or more of U.S. patent application Ser. Nos. 13/714,209, 14/300,074, 14/300,055, and 14/300,021, and U.S. Pat. No. 9,653,820, all incorporated herein by reference in their entireties in some embodiments. The term transmit/receive module (TRM) refers to a circuit including at least one active integrated circuit for performing phase shifting and amplification in a receive path, a transmit path or a transmit/receive path. The TRM can operate as a receive only module, a transmit only module, or as a combined transmit receive module in some embodiments. 
     The spherical phased array space feeds collect the naturally spherical propagating electromagnetic (EM) wave from the primary feed on a spherical “pickup antenna array” to minimize spill over loss in some embodiments. The primary feed antenna provides a nearly omnidirectional radiation pattern in its forward hemisphere in some embodiments. The spherical phased array space feed can be used with planar, cylindrical, semi-cylindrical, single curved, spherical, hemispherical, and doubly curved apertures in some embodiments. 
     Ultra-wideband (UWB) steerable antenna arrays using space feed technology can be used in a variety of applications including but not limited to: wireless communications, remote sensing, biological or medical microwave imaging, aviation applications, military applications, and/or the like. The UWB steerable antenna arrays can include, but are not limited to, phased-array antenna systems or electronically scanned array (ESA) antenna systems, such as active electronically-scanned array (AESA) antenna systems. The UWB steerable antenna array systems operate at frequency bandwidths within 2 to 40 GHz. 
     UWB steerable antenna array systems can be manufactured using thin metal planar antenna elements as described in U.S. patent application Ser. No. 15/048,969 incorporated herein by reference in its entirety and assigned to the assignee of the present application in some embodiments. A UWB steerable antenna array system can include a plurality of thin metal structures (or sheet metal structures), each of which represents a one-dimensional (1-D) array of thin metal planar antenna elements. Using manufacturing processes such as laser cutting, chemical etching, or electroforming, sheet metal structures with high resolution (or dimensionally precise) planar antenna elements can be manufactured at a relatively low cost. For example, the accuracy of laser cutting is within ±5 micrometers (μm). The sheet metal structures can be arranged substantially parallel to one another to form a two-dimensional (2-D) array of thin metal planar antenna elements. Each thin metal structure can be mechanically and electrically coupled to a respective printed circuit board (PCB). The sheet metal structures can be mechanically coupled to each other using one or more alignment structures. In some embodiments, the UWB steerable antenna array system can include at least one electromagnetic shielding structure for shielding one or more active/electronic circuit components from electromagnetic radiations associated with the planar antenna elements, and/or the planar antenna elements from electromagnetic radiations associated with the one or more active/electronic circuit components. 
     With reference to  FIG. 1 , an antenna array, embodied as an AESA assembly  10 , includes a feed antenna  12  and a number of cards  15   a - g . The number of cards  15   a - g  can be any number and can be provided in various physical arrangements and orientations. As shown in  FIG. 1 , the AESA assembly  10  includes a spherical space feed pickup  14 . 
     The cards  15   a - g  are provided in a configuration and can be separated from each other by a support member  16 . The support member  16  is a wedged shaped structure provided between the cards  15   c  and  15   d  in  FIG. 1  but can be provided between any number of the cards  15   a - g . The support member  16  is anti-blow-by wedges in some embodiments. The anti-blow by wedges are designed to prevent parasitic feed radiation not received by cards  15   a - 15   g  to radiated between the cards  15   a - 15   g . The support member  16  provides a receptacle or interface for mounting and spacing the cards  15   a - g  for the AESA assembly  10 . In some embodiments, the support member  16  is part of a chassis between the cards  15   a - g  to extinguish primary feed RF blow-by and facilitate mechanical assembly. In some embodiments, the cards  15   a - g  plug into a spherical metal cap. 
     The AESA assembly  10  is shown as a vertical polarization (VP) array arrangement but can be rotated 90 degrees for a horizontal polarization (HP) array arrangement in some embodiments. The AESA assembly  10  is arranged as a partial cylindrical array, having an azimuth of approximately 90 degrees, in some embodiment. The cards  15   a - g  are provided in a full cylindrical array arrangement or any portion thereof and are evenly spaced apart in some embodiments. The cards  15   a - g  can be arranged at other spacings and in other shapes. 
     The feed antenna  12  is a device for providing EM to the cards  15   a - g  or receiving EM from the cards  15   a - g . The feed antenna  12  includes a cylindrical or spherical antenna element in some embodiments. The feed antenna  12  is disposed proximate the cards  15   a - g . The feed antenna is a horn antenna or any type of antenna or set of antennas the have the appropriate beam width. The feed antenna  12  can be a low-gain antenna, an open-ended wave guide, a physically short horn, a dipole, cross-dipole, a micro strip patch, or a spiral antenna in some embodiments. The feed antenna  12  has sufficient gain and bandwidth to illuminate the spherical space feed pickup  14  in some embodiments. 
     With reference to  FIGS. 1 and 2 , a card  15   a  which is similar to cards  15   b - g  includes pickup antenna elements  18   a - e  and radiating antenna elements  20   a - e . The card  15   a  also includes transmit receive modules (TRMs)  22   a - e  corresponding to the pickup antenna elements  18   a - e  and radiating antenna elements  20   a - e , respectively. The card  15   a  serves as a cross section of a generally conformal AESA lens radiating element. 
     The card  15   a  is a printed circuit board structure card housing the antenna elements  18   a - e  and  20   a - e  in some embodiments. The radiating antenna elements  20   a - e  can be provided as part of a structure  24  embodied as a metallic structure. In some embodiments, the radiating elements  18   a - e  are on a common stencil card such as the structure  24 . Similarly, the pickup antenna elements  18   a - e  can be provided as a metallic structure  25  (e.g., sheet metal) and are provided on a common stencil card. In some embodiments, the pickup antenna elements  18   a - e  and the radiating antenna elements  20   a - e  are printed circuit board conductors disposed on cards  15   a - g  embodied as printed circuit boards. The antenna elements  18   a - e  are arranged in a semi-circle on a curved edge  28  of the card  15   a  to facilitate efficient RF energy transfer between feed antenna  12  and pick up antennas  18   a - 18   e.    
     The structures  24  and  25  include a thin metal antenna array and include metallic structures arranged substantially parallel or in a curved fashion with respect to one another. While the antenna elements  18   a - e  and  20   a - e  are schematically shown as triangular or bullet shaped structures, various shapes and sizes can be utilized. The antenna elements  18   a - e  and  20   a - e  are made of a conductive metal or alloy such as stainless steel, copper, brass, or any other conductive metal or alloy or are printed circuit board pads of copper or copper alloy in some embodiments. 
     Each card  15   a - g  can be mechanically and electrically coupled to sheet metal structures  25  and  24  for the respective elements  18   a - e  and  20   a - e . Each metallic structure  24  and  25  can be fully integrated or partially integrated in (25 or partially blended with) a respective printed circuit board card associated with the cards  15   a - g . In particular, a portion of the metallic structure can be soldered, welded or otherwise attached to the respective printed circuit board such that the radiating antenna elements  20   a - e  extend beyond the printed circuit board, for example, along (or parallel to) a plane representing a planar surface of the printed circuit board. In some embodiments, each metallic structure can be mechanically coupled (e.g., soldered or welded) to a respective printed circuit board such that the radiating antenna elements  20   a - e  of that sheet metal structure extend beyond the respective printed circuit board along a plane perpendicular to the card  15   a . The pickup antenna elements  18   a - e  can be similarly disposed. The antenna card assemblies can also be realized through non-traditional manufacturing techniques such as 3D additive manufacture, plated traces on plastic (dielectric substrate slabs, substrates made using injections molded plastic. 
     Connectors  26   a - e  corresponding to the TRMs  22   a - e , antenna elements  18   a - e  and antenna elements  20   a - e  connect the TRMs  22   a - e  to respective antenna elements  18   a - e . The connectors  26   a - e  are printed circuit board transmission lines in some embodiments, each having an equal length. Various printed transmission line configurations such as microstrip, stripline grounded coplanar waveguide, etc., are possible. In some embodiments, the TRMs  22   a - e  can be coupled directly to antenna elements  20   a - e  or coupled via additional connecting path transmission lines. The connectors  26   b - d  have a serpentine configurations to achieve equal lengths with connectors  26   a  and  26   e  in some embodiments. 
     Bias control and ground lines for the TRMs  22   a - e  can be provided in radio frequency (RF) benign areas of the cards  15   a - g  for the next level of interconnections. The TRMs  22   a - e  can be modules as described in U.S. patent application Ser. Nos. 13/714,209, 14/300,074, 14/300,055, and 14/300,021, and U.S. Pat. No. 9,653,820, all incorporated herein by reference in their entireties in some embodiments incorporated herein by reference. The TRMs  22   a - e  are devices that provide processing, amplification, conditioning, and phase (or delay) control for signals travelling between the antenna elements  20   a - e  and  18   a - e  in some embodiments. 
     With reference to  FIG. 3 , a card  40  can be used as one of the cards  15   a - g  in the AESA assembly  10  ( FIG. 1 ). The card  40  can be utilized as part of an HP cylindrical AESA assembly. The card  40  is arranged with other cards at varying angles about an x-axis  44 . A z-axis  42  is provided in line with the feed antenna  12 . The card  40  has a straight edge  46  associated with radiating elements  48   a - e  and a curved edge  50  associated with pickup antenna elements  52   a - e.    
     With reference to  FIG. 4 , a card  58  can be used as one of the cards  15   a - g  in the AESA assembly  10  ( FIG. 1 ). The card  48  can be utilized as part of a VP cylindrical AESA assembly. The card  58  is arranged with other cards at a varying angle about the z-axis  42 . The feed antenna  12  is provided in line with the x-axis  44 . The card  58  has a straight edge  60  associated with the radiating antenna elements  62   a - e . The pickup antenna elements  64   a - e  are provided along a curved edge  66 . 
     With reference to  FIG. 5 , a card  68  can be used as one of the cards  15   a - g  in the AESA assembly  10  ( FIG. 1 ). The card  68  along with other cards can be assembled about a varying angles about the x-axis  44  for an HP hemisphere AESA structure. The card  68  includes radiating antenna elements  70   a - e  along a curved edge  72 . The pickup antenna elements  74   a - g  are provided along a curved edge  76 . The curved edges  72  and  76  can be semi-circular edges differing from each other by a fixed radius. The electric (E) field component vector is disposed tangent to the edge  72  for the card  68  in some embodiments. 
     With reference to  FIG. 6 , a card  78  can be used as one of the cards  15   a - g  in the AESA assembly  10  ( FIG. 1 ). The card  78  is similar to the card  68  and with other cards can be assembled at varying angles about the z-axis  42  as a VP hemisphere AESA structure. Radiating antenna elements  80   a - g  are provided along a curved edge  82  and pickup antenna elements  84   a - g  are provided along a curved edge  86 . The electric field component (E m )vector is disposed tangent of the edge  82 . Curved edges  82  and  86  can be semi-circular edges differing from each other by a fixed radius. 
     With reference to  FIGS. 7 and 8 , a dual linear polarization cylindrical AESA assembly  100  includes cards  102   a - g  and cards  108   a - g . The cards  102   a - g  and cards  108   a - g  can have toothcomb notches for assembly. An egg crate sub-assembly can be provided for receiving the cards  102   a - g  and cards  108   a - g.    
     With reference to  FIG. 9 , the card  102   a , similar to the cards  102   b - f , includes a curved edge  112  and a curved edge  118  associated with pickup radiating elements  116   a - g  and radiating antenna elements  114   a - g , respectively. The E field component vector is disposed tangent to the edge  114 . 
     With reference to  FIG. 10 , the card  108   a , similar to the cards  108   b - f , includes a curved edge  122  and a straight edge  124  associated with pickup antenna elements  126   a - e  and radiating elements  128   a - e , respectively. 
     With reference to  FIG. 11 , a dual linear polarization hemispherical ASEA assembly  140  includes cards  150   a - c  and cards  152   a - g . The AESA assembly  140  can utilize notches in the cards  152   a - g  and  150   a - c.    
     With reference to  FIG. 12 , the card  150   a  is similar to the cards  150   b - c  which are provided at varying angles about the x-axis  44 . The card  150   a  includes radiating antenna elements  160   a - f  along an edge  162  whose tangent is parallel with the E field. The pickup antenna elements  166   a - e  are provided along a curved edge  168 . 
     With reference to  FIG. 13 , the card  152   a  which is similar to the cards  152   b - e  includes a curved edge  170  associated with radiating antenna elements  172   a - f . The cards  152   a - g  are provided at varying angles about the z-axis  42 . The EM field vector is tangent to the curved edge  170 . The pickup antenna elements  176   a - f  are provided on a curved edge  178 . Each of the configurations discussed with reference to  FIGS. 7-13  provide general elliptical polarization, including Right Hand Circular Polarization (RHCP) and Left Hand Circular Polarization (LHCP). 
     With reference to  FIG. 14 , a planar array subsection of a spherical feed is integrated into a planar AESA aperture according to some embodiments. The feed antenna  12  is provided above, below or in line with a card  206 . The card  206  includes pickup elements  212  and radiating antenna elements  214  extending from the card  206 . The card  206  includes RF feed lines and TRMs between the pickup elements  212  and radiating antenna elements  214 . The pickup antenna elements  212  follow a circular contour within card  206  and a 3-dimensional (D) wave guide connects the pickup antenna elements  212  to the radiating antenna elements  214 . In addition, 3D waveguides may incorporate RF T/R modules with bias and control lines routed on the exterior surfaces of the waveguide. The 3-D wave guide connects can be realized utilizing stacked computer CNC milled plates to realize arbitrary 3-D feedback paths, utilizing 3-D additive manufacture or utilizing flexible strip line or PCB and liquid crystal polymer (LCP) technology. 
     With reference to  FIG. 15 , a planar array spherical feed integrated into a planar AESA assembly aperture  240  is shown. The aperture  240  includes cards  242   a - g . AESA assembly  240  can provide a transmit cosine squared (COS 2 ) pattern. The feed antenna  244  is a horn or any of several different types of antennas that have the appropriate beam width and polarization (e.g., a Vivaldi antenna).  FIG. 15  shows a COS 2  tapered pattern in the H-Plane of the antenna (with the polarization in the direction of the card). An additional taper can be implemented in the E-plane by varying the elements distances to the feed. 
     The cards  242   a - g  can be arranged in a spherical space for both the pickup elements and the radiating elements. The cards  242   a - g  are rectangular and staggered in an arc. The power received by the antenna elements on the outside portions  246   a - b  of the cards  242   a - g  may be less than the power closer to the center, and therefore a natural amplitude taper can be optimized for the vertical plane which is desirable in certain applications. 
     With reference to  FIG. 16 , a space feed sensor assembly  300  can be configured as a sensor using a central space feed antenna  302  and AESA subarrays  304   a - e . The central space feed antenna  302  can be comprised of five (or other number) single channel horns or wide beam planar elements. The central space feed antenna  302  is configured for multiple space feeds at the geometric center of the assembly  300  in some embodiments. Each of the co-located multiple space feeds can feed one of the AESA subarrays  304   a - e . The AESA subarrays  304   a - e  are racked and stacked to provide hemispherical coverage and yet has a less complicated feed architecture. 
     Each AESA subarray  304   a - e  can utilize one or more of the AESA assemblies described with reference to  FIGS. 1-15  and is configured to provide hemispherical or spherical coverage using multiple planar facets in some embodiments. Each AESA subarrays assemblies  304   a - e  includes a set of planar space arrays in some embodiments. Each ASA subarray  304   a - e  includes two-dimensional planar assemblies including TRMs in some embodiments. Each space feed distribution network  304   a - e  includes amplifiers and phase shifters (or time delay units) in some embodiments. 
     In some embodiments, the assembly  300  is configured as an electromagnetic wave (EW) sensor providing hemispherical coverage with transmit and receive capability. In some embodiments, the transmit and receive sensors can be separable. Each array facet can add two (or more) beams to the system. The six facet approach has six space fed arrays in some embodiments. More facets are possible with each increasing the number simultaneous beams within the system by two, with each beam covering a subsector of the hemisphere. The multiple beam approach is achieved through multiple phase shifters or time delay units on the space feed array and thus multi-beam at separate frequency points is available in some embodiments. Natural space feed COS 2  taper is available on the aperture distribution. One side of the assembly  300  is not shown in  FIG. 16  to show the central space feed antenna  302 . 
     With reference to  FIG. 17 , hemispherical coverages or doubly curved conformal partial spheres are possible using the multiple assemblies  304 . For example, a pyramidal coverage  402 , a truncated pyramidal coverage  404 , a four-sided truncated pyramidal coverage  406 , a hexagonal pyramidal coverage  408 , a hemispherical coverage  440  and a semi-hemispherical coverage  420 ? are available. Spherical dome arrays consisting of angular planar facets (e.g., soccer balls, geodesic structures with planar triangular, pentagonal, and hexagonal planar facets are available. End-side pyramidal cluster of structures are also available. Truncating end-side pyramidal structures with a outwardly looking pattern array faces are available. 
     TRMS are not shown in  FIGS. 3-17  for simplicity. Although particular numbers or cards are shown in the  FIGS. 1, 7, and 11 , additional cards or less cards can be utilized. Other types of polarization and combinations of polarization configurations are possible depending on design criteria and system parameters. 
     In some embodiments, one or more alignment structures can be used with the antenna elements and can comprise one or more alignment rods. The antenna array system can further include a plurality of spacers arranged along each of the one or more alignment rods. Each spacer can be configured to separate a respective pair of adjacent metallic structures by a predefined distance. In some embodiments, the one or more alignment structures can include mechanical housing structures that are configured to be mechanically coupled to each other. Each mechanical housing structure can be configured to receive a respective sheet metal structure of the plurality of sheet metal structures or a respective PCB of the PCBs. The metallic structures can be arranged parallel to each other when the mechanical housing structures are mechanically coupled to each other. 
     The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are included within the scope of the inventive concepts disclosed herein. The order or sequence of any operational flow or method operations may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the inventive concepts disclosed herein.