This disclosure relates generally to communication systems, and more specifically to a reflector antenna system and method for manufacture.
Antennas that are designed to communicate long distances, such as to and from satellites, are designed to include a reflector that collimates or focuses an associated radio signal. Such reflector antennas are typically fabricated in panel portions that include a reflector skin formed of a light material (e.g., aluminum). The panel portions are typically aligned in such a manner as to attempt to optimize a parabolic profile, which can typically involve mechanical tuning of the coupling of the panel portions together. To manufacture a panel portion, the reflector skin is typically formed in a reflector profile, such as a parabolic reflector profile, to optimize the collimation or focusing of the radio signal. The reflector skin is typically coupled to a perimeter frame to maintain the reflector profile of the reflector skin, and the perimeter frames of the panel portions can be coupled together to form the reflector antenna.
One example includes a method for fabricating a radial antenna panel of a reflector antenna. The method includes coupling first and second frame members to respective sidewalls of a panel bonding tool via fastening features to engage a through-hole pattern of each of the respective frame members and bend the frame members to form a perimeter frame. A longitudinal surface of each of the frame members corresponding to a reflector profile of the reflector antenna extends beyond a longitudinal surface of the respective sidewalls along a length of the respective sidewalls. The method also includes applying an adhesive to each of the frame members of the perimeter frame, and adhering a reflector skin to the perimeter frame to form a radial antenna panel. The radial antenna panel has the reflector profile. The method further includes decoupling the radial antenna panel from the panel bonding tool upon curing of the adhesive.
Another example includes a reflector antenna system. The system includes a hub at an axial center of a reflector antenna, and a plurality of radial antenna panels each comprising a plurality of frame members and a respective reflector skin. Each of the frame members includes a through-hole pattern along a radial length of the respective frame member. The system further includes a plurality of ribs. Each of the ribs can be coupled to and radially extending from the hub and interconnecting a pair of the respective radial antenna panels. Each of the ribs includes a through-hole pattern along a length of the respective one of the ribs, such that each of the plurality of ribs interconnects the pair of the radial antenna panels via fastening hardware extending through the corresponding through-hole patterns of the respective rib and respective frame members. The corresponding through-hole patterns of the respective rib and respective frame members collectively define a reflector profile of the reflector antenna from the axial center to the periphery of the reflector antenna.
This disclosure relates generally to communication systems, and more specifically to a reflector antenna system and method for manufacture. A reflector antenna system is formed of a plurality of radial antenna portions. Each of the radial antenna portions is formed from a pair of frame members and a reflector skin, and is fabricated using a panel bonding tool. The panel bonding tool can include a pair of sidewalls having fastening features that are arranged in a reflector profile of the reflector antenna. As described herein, the term “reflector profile” describes a cross-sectional radial profile of the reflector of the reflector antenna system. For example, the reflector profile can be a parabolic antenna, such as corresponding to a main reflector or a sub-reflector of an antenna (e.g., a Cassegrain antenna). For example, the reflector profile can be any of a variety of contours, such as concave, convex (e.g., for a sub-reflector), or flat.
To fabricate a radial antenna panel, the frame members are secured to the sidewalls of the panel bonding tool via the fastening features. For example, the fastening features can be arranged as sliding pins (e.g., spring-mounted) that can engage with through-holes (e.g., through-hole slots) along a length of the respective frame members. The frame members can be configured as an extruded material that is selected for stiffness, but can include kerf slits arranged periodically along a longitudinal length, such that the frame members can be bent to form the reflector profile along a surface of the respective frame members. The frame members can therefore be included as part of a perimeter frame (e.g., also including interconnecting members between the respective frame members) that is associated with the radial antenna panel and formed on the panel bonding tool. An adhesive can be applied to the respective surfaces of the frame members, and the reflector skin can be applied to the adhesive. For example, the panel bonding tool can include clamps that can be applied to provide pressure to the reflector skin onto the frame members during curing of the adhesive.
The radial antenna panel can then be removed from the panel bonding tool and can be coupled to one of a respective plurality of ribs coupled to a hub defining an axial center of the reflector antenna. For example, each of the radial antenna panels can be coupled between a pair of ribs, such that each rib supports a pair of radial antenna panels. For example, the through-holes associated with the frame members can facilitate coupling to a through-hole pattern associated with the respective rib, such that a given bolt can pass through a frame member associated with a first radial antenna panel, the respective rib, and a frame member associated with a second radial antenna panel. The through-hole pattern of the respective rib can be approximate the same as the fastening feature pattern of the sidewalls of the panel bonding tool, such that the through-hole pattern of the rib can exhibit the reflector profile of the reflector antenna. For example, the through-hole pattern of the frame members can include a precision through-hole that is most proximal to the hub to radially align the radial antenna panels for optimal metrology of the reflector antenna. The remaining through-holes extending longitudinally along the frame members can correspond to through-hole slots to accommodate thermal effects (expansion and contraction) affecting the radial antenna panel.
The antenna system 10 includes a hub 16 that defines an axial center of the antenna system 10, as well as a plurality of ribs 18 that are coupled to and radially extend from the hub 16. The plurality of ribs 18 are each also coupled to a respective plurality of radial antenna panels 20 that radially extend between adjacent ribs 18. Therefore, a given one of the ribs 18 can be coupled to an adjacent pair of the radial antenna panels 20. Each of the radial antenna panels 20 is demonstrated as including a perimeter band bracket 22. The perimeter band brackets 22 thus collectively surround the perimeter of the antenna system 10 and extend in the anterior direction of the antenna system 10. As an example, the perimeter band brackets 22 can provide greater structural strength to the antenna system 10, such as to maintain the reflector profile under wind and gravity loading conditions.
As described in greater detail herein, each of the radial antenna panels 20 can include a perimeter frame and a reflector skin that is coupled to the perimeter frame, where the reflector skin provides has a surface from which a given radio frequency (RF) signal is reflected for transmission and/or receipt of the RF signal. In the first isometric view 12, the radial perimeters of reflector skins of adjacent radial antenna panels 20 are demonstrated as approximately flush, such that the ribs 18 are substantially covered by the reflector skin of the respective radial antenna panels 20. Therefore, the anterior surface of the antenna system 10 is substantially smooth to mitigate diffraction of the RF signal that reflects from the anterior surface of the antenna system 10.
The radial antenna panel includes a first frame member 56, a second frame member 58, and a reflector skin 60. The first and second frame members 56 and 58 are each coupled to opposite edges of the reflector skin 60 and can be fabricated substantially identically, as described in greater detail herein. As an example, the reflector skin 60 can be formed in a variety of ways, such as stretch-formed or vacuum-formed. The radial antenna panel also includes a nose bracket 62 that interconnects the frame members 56 and 58 at a first end of the respective frame members 56 and 58 and a corner bracket 64 that interconnects the frame members 56 and 58 at a second end of the respective frame members 56 and 58 opposite the first end. The frame members 56 and 58 and the interconnect members 62 and 64 can collectively form a perimeter frame for the radial antenna panel to which the reflector skin 60 is coupled (e.g., via an adhesive, screws, or rivets) which extends therebetween. In the example of
For example, the frame members 56 and 58, the interconnect members 62 and 64, and the reflector skin 60 can be formed from a light metallic material, such as aluminum. However, the frame members 56 and 58, the interconnect members 62 and 64, and the reflector skin 60 can alternatively be formed from a non-metal substrate material with a reflector coating (e.g., on only the anterior surface). For example, the non-metal substrate material can be a plastic material that can be solvent bonded, friction welded, or ultrasonic welded to form the radial antenna panel, and a a reflector coating can be applied to the anterior surface of the reflector skin 60 via soldering, TIG welding, spot welding, or any other method of bonding. For example, the choice of materials for the frame members 56 and 58, the interconnect members 62 and 64, and the reflector skin 60 can be selected to mitigate shrinkage/warpage, to affect final accuracy, weight, and/or stiffness of the radial antenna panel. As another example, the reflector anterior coating can be selected to effect electromagnetic performance.
The frame member 102 is demonstrated in multiple views in Cartesian coordinate space in the example of
The frame member 102 also includes a plurality of through-holes arranged as a through-hole pattern along the longitudinal length of the frame member 102. The through-hole pattern includes a precision through-hole 120 and a plurality of through-hole slots 122. As described herein, the term “precision” in the context of the through-holes refers to a high-degree of machined tolerance, such as to a precision of at least one-hundredth of an inch (e.g., between approximately 0.001″ and approximately 0.005″). While the through-hole 120 and the through-hole slots 122 are demonstrated as having rounded edges, it is to be understood that other types of through-holes (e.g., square or diamond) can be implemented. As an example, the precision through-hole 120 can be precision located in each of the X-axis and the Y-axis for radially aligning the radial antenna panel about the hub, as described in greater detail herein. As another example, the through-hole slots 122 can be precision located along the Y-axis for bending the frame member 102 on the associated panel bonding tool to provide an approximation of the reflector profile with respect to the top portion 112, as also described in greater detail herein. The through-hole slots 122 can be likewise implemented for coupling the resulting radial antenna panel to the ribs (e.g., the ribs 18 in the example of
The panel bonding tool 150 includes a pair of sidewalls, demonstrated at 152 and 154, that includes a plurality of fastening features 156 that are configured to engage with the through-hole slots 122 of respective frame members 102 (the reference to which is interchangeable hereinafter with the frame members 56 and 58). In the example of
As described previously, the frame members 56 and 58 are coupled to the sidewalls 152 and 154, respectively, during fabrication of a given radial antenna panel. In addition, the interconnect members 62 and 64 can be coupled to the frame members 56 and 58 (e.g., via an adhesive) to form the perimeter frame of the radial antenna panel. For example, the fastening features 156 are arranged along the sidewalls 152 and 154 in the reflector profile of the reflector antenna system 10. The panel bonding tool 150 therefore has a concave contour to a top side of the sidewalls 152 and 154 to which the frame members 56 and 58 are coupled. Accordingly, the panel bonding tool 150 can be arranged as a “female” panel bonding tool, as opposed to “male” panel bonding tools having a convex topside that is implemented for forming radial antenna panels in a typical reflector antenna assembly methodology. Therefore, when the respective frame members 56 and 58 are bent to facilitate coupling to the respective sidewalls 152 and 154, the top portion 112 of the respective frame member 102 can approximate the reflector profile of the reflector antenna system 10 (e.g., having a parabolic contour).
In the example of
The reflector skin 60 can then be applied to the perimeter frame via the parallel alignment pins 166 being provided through the respective guide holes 66 formed in the reflector skin 60. As an example, the guide holes 66 can also be implemented to establish a fiducial plane for metrology inspection, such as measured to ideal surface profile accuracy, upon completion of the given radial antenna panel. The reflector skin 60 can be pressed onto the adhesive that is applied to the surfaces of the top portion 112 of the respective frame members 102. As an example, based on the relative dimension of the through-hole slots 122 relative to the surface of the top portion 112 of the frame members 102, and further relative to the dimension of the respective sidewalls 152 and 154, the lateral portion 116 of the frame members 102 can extend beyond the sidewalls 152 and 154, such that the top portion 112 of the frame members 102 can be elevated relative to a “top” surface of the sidewalls 152 and 154. Therefore, in response to the application of the reflector skin 60 to the adhesive on the top surface of the top portion 112, any potential “squeeze-out” of the adhesive will not contact any of the portions of the panel bonding tool 150. For example, application of a sufficient amount of adhesive to provide a squeeze-out may ensure that air gaps and voids are not present between the reflector skin 60 and frame members 102. Accordingly, the panel bonding tool 150 can remain clean without any of the adhesive from squeeze-out curing on any of the surfaces of the panel bonding tool 150.
The center panel gravity stop 168 can be adjusted to a predetermined height (e.g., via a screw adjustment). Therefore, when the reflector skin 60 is provided onto the adhesive on the perimeter frame, the convex surface (e.g., posterior side) of the reflector skin 60 can contact the center panel gravity stop 168 to ensure that the reflector skin 60 does not experience deformation from gravity-induced droop of the center portion of the reflector skin 60. Upon contacting the adhesive with the reflector skin 60, the outer clamps 162 can be engaged to provide pressure of the reflector skin 60 onto the adhesive while the adhesive cures. As an example, the adhesive can include one or more physical spacing elements to provide a standoff distance between the surface of the top portion 112 of the frame members 56 and 58 and the opposing surface of the reflector skin 60 separated by the adhesive. For example, the physical spacing element(s) can include beads, string, or other rigid physical objects to prevent direct contact between the surfaces of the reflector skin 60 and the frame members 56 and 58. As a result, the physical spacing element(s) can establish a minimum bonding thickness to establish sufficient bonding between the surfaces of the reflector skin 60 and the frame members 56 and 58. For example, the bonding thickness can vary from between approximately 0.012″ at an approximate center of the top portion 112 between the kerf slits 118 and approximately 0.054″ at the top portion 112 nearest the kerf slits 118 based on a parabolic reflector profile of the reflector skin 60. After the adhesive has cured, the outer clamps 162 can be disengaged and the resultant radial antenna panel can be removed from the panel bonding tool 150 (e.g., after removing the alignment pins 166 to facilitate sliding the radial antenna panel off of the panel bonding tool 150).
The diagram 400 also demonstrates a reflector skin 418 coupled to the top surface 410 of the frame member 404 via an adhesive 420. Because of the extension 414 of the frame member 404 relative to the sidewall 402, the adhesive 420 does not contact the sidewall 402 when any of the adhesive 420 squeezes out from between the top surface 410 of the frame member 404 and the reflector skin 418. Upon contacting the adhesive 420 with the reflector skin 418, the diagram 400 demonstrates an outer clamp 422 (e.g., of the outer clamps 162) that is engaged to provide pressure of the reflector skin 418 onto the adhesive 420 while the adhesive 420 cures. As described previously, the adhesive 420 can include one or more physical spacing elements to provide a standoff distance between the top surface 410 of the frame member 404 and the opposing surface of the reflector skin 418 separated by the adhesive 420. In addition, the diagram 400 demonstrates a release hole, illustrated by dotted lines 424, that facilitates release of the inner clamp 406 while the reflector skin 418 is adhered to the top perimeter frame that includes the frame member 404. Therefore, the release hole 424 provides access to a release handle, demonstrated at 426, for disengaging the inner clamp 406 for removing the perimeter frame from the panel bonding tool 200.
The methodology for fabricating the radial antenna panel 452 can therefore correspond to a significantly more efficient manner of fabricating a radial antenna panel than typical processes for fabricating a radial antenna panel. For example, as described previously, a typical radial antenna panel can be fabricated on a male panel bonding tool that implements a vacuum sealing system to vacuum secure a reflector skin onto a convex surface. Such a male panel bonding tool can be significantly more expensive to manufacture than the panel bonding tool 150 described herein based on additional materials and based on the inclusion of a vacuum system that is obviated for the design of the panel bonding tool 150. Additionally, for the typical fabrication methodology, the perimeter frame is assembled separately from the male panel bonding tool, and is applied to the adhesive that is provided on the surface of the vacuum-secured reflector skin. As a result, the perimeter frame in the typical fabrication methodology is formed in a manner that does not include fastening features on the panel bonding tool that pre-define the reflector profile for the resultant radial antenna panel. Instead, the perimeter frame of the typical fabrication methodology is bent to conform to the reflector profile contour of the reflector skin while it is vacuum-secured to the male panel bonding tool, directly onto the applied adhesive. Such an arrangement can be significantly more time consuming and can provide for more opportunities for errors in assembly of the perimeter frame and the securing of the perimeter frame to the adhesive. Furthermore, when the perimeter frame is pressed onto the adhesive that has been applied to the panel skin in the typical fabrication method, adhesive that squeezes out of the bonding of the perimeter frame to the reflector skin can flow over the perimeter of the reflector skin directly onto the surfaces of the male panel bonding tool. Accordingly, additional cleaning can be required in the typical fabrication methodology. However, the fabrication methodology described in the examples of
In the example of
For example, the precision through-hole 120 of a frame member 102 (e.g., corresponding to the first frame member 56) of a first radial antenna panel 20 and the precision through-hole 120 of a frame member 102 (e.g., corresponding to the second frame member 58) of a second radial antenna panel 20 can each be aligned with the alignment through-hole 554 of the rib 550. Therefore, a single through-bolt can couple the first and second radial antenna panels 20 to the rib 550 via the precision through-holes 120 and the alignment through-hole 554. For example, because the alignment through-hole 554 can be the through-hole most proximal to the hub, the coupling of first and second radial antenna panels 20 to the rib 550 via the precision through-holes 120 and the alignment through-hole 554 can radially align the radial antenna panels approximately uniformly about the center axis of the reflector antenna.
Similarly, each of the through-hole slots 122 of the frame member 102 (e.g., corresponding to the first frame member 56) of the first radial antenna panel 20 and the through-hole slots 122 of the frame member 102 (e.g., corresponding to the second frame member 58) of the second radial antenna panel 20 can each be aligned with each of the respective through-holes of the second set of through-holes 556 of the rib 550. Therefore, a single through-bolt can couple the first and second radial antenna panels 20 to the rib 550 via each of the through-hole slots 122 and each of the second set of through-holes 556, respectively. For example, each of the through-holes of the second set of through-holes 556 can be approximately aligned to a longitudinal center of the respective through-hole slots 122. Therefore, the radial antenna panels 20 can radially slide along coupling through-bolt via the respective through-hole slots 122 in response to expansion and contraction of the frame members 56 and 58 of the respective radial antenna panel 20. Accordingly, as described herein, the use of through-bolts for coupling the radial antenna panels 20 to the rib 550 can provide for a substantially simplistic and uniform manner of assembling the reflector antenna, without having to adjust the individual radial antenna panels to optimize the reflectivity of the resultant reflector antenna, as can be performed in typical reflector antennas.
The diagram also demonstrates that the lateral portion 116 of each of the frame members 608 and 612 extends farther along a Y-axis in Cartesian coordinate space than the rib 606. Thus, a peripheral edge of the rib 608 is not flush with the top surface of the top portions 112 of the respective frame members 610 and 614, resulting in the top surface of the top portions 112 of the respective frame members 610 and 614 being elevated greater than the peripheral edge of the rib 608 with respect to the Y-axis. Therefore, the reflector skins 610 and 614 can overlap and substantially cover the peripheral edge of the rib 608. As a result, the associated reflector antenna system 10 can have fewer interruptions in the reflective surface formed by the reflector skins 60 of each of the radial antenna panels 20, and can therefore exhibit a greater reflectivity for improved performance of the reflector antenna system 10.
In view of the foregoing structural and functional features described above, a methodology in accordance with various aspects of the present invention will be better appreciated with reference to
What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Additionally, where the disclosure or claims recite “a.” “an,” “a first,” or “another” element, or the equivalent thereof, it should be interpreted to include one or more than one such element, neither requiring nor excluding two or more such elements. As used herein, the term “includes” means includes but not limited to, and the term “including” means including but not limited to. The term “based on” means based at least in part on.
This application claims priority from U.S. Provisional Application No. 62/826,531, filed 29 Mar. 2019, which is incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2020/025428 | 3/27/2020 | WO | 00 |
Number | Date | Country | |
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62826531 | Mar 2019 | US |