Abstract:
A cable network antenna and a manufacturing method thereof are provided. The cable network antenna maintains correct positions of nodes at which a plurality of cables intersect, using a circumferential truss that minimizes transformation of a reflecting surface. Accordingly, accuracy of the reflection surface is achieved.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2010-0081520 and of Korean Patent Application No. 10-2011-0035694, respectively filed on Aug. 23, 2010 and Apr. 18, 2011, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a cable network antenna which is a deployable antenna and a manufacturing method thereof. 
         [0004]    2. Description of the Related Art 
         [0005]    A deployable antenna is a type of reflector antenna, which may be folded into a small volume and deployed into an antenna having a large opening surface. Types of deployable antennas include a circumferential truss network deployable antenna, an umbrella deployable antenna, a truss deployable antenna, and a hybrid deployable antenna. 
         [0006]    The deployable antenna is conveniently stored and transported since it may be deployable from a small folded state. However, unlike a fixed antenna, the deployable antenna has a difficulty in accurately forming the reflector because nodes forming a reflecting surface of the deployable antenna may be displaced in a deployed state. Accordingly, there is a desire for a new secure deployable antenna in which a shape and angle of the reflecting surface are not varied when the deployable antenna is deployed. 
       SUMMARY 
       [0007]    An aspect of the present invention provides a circumferential truss network deployable antenna that minimizes deformation of a reflecting surface in a deployed state. 
         [0008]    According to an aspect of the present invention, there is provided a cable network antenna including a front net having a curved surface shape that includes a plurality of grids sectioned by a plurality of intersecting first cables and a rear net having a curved surface shape that includes a plurality of grids sectioned by a plurality of intersecting second cables, a mesh configured to cover the plurality of grids of the front net from a lower part of the front net, a node cover configured to cover nodes of the front net from an upper part of the mesh and to receive the plurality of first cables at the nodes of the front net, a node body configured to receive a protruded portion generated by the nodes of the front net and to be connected with the node cover disposed at the upper part of the mesh from a lower part of the mesh, and a tension tie connection unit configured to be connected with the node body and also connected with tension ties determining a distance between the rear net and the front net. 
         [0009]    The node cover may include a plurality of recesses to receive the plurality of first cables such that the plurality of first cables are guided at a predetermined angle from the respective nodes of the front net. 
         [0010]    The node body may include a hole disposed in a center to receive the protruded portion generated as the plurality of first cables overlap at the nodes of the front net. 
         [0011]    The tension ties may be connected with the tension tie connection unit having a hook form and include an elastic medium disposed in a center. 
         [0012]    The cable network antenna may further include a circumferential truss configured to support the front net, the rear net, and the tension ties to achieve a deployment mechanism of the cable network antenna. 
         [0013]    According to an aspect of the present invention, there is also provided a cable network antenna including a front net having a curved surface shape that includes a plurality of grids sectioned by a plurality of intersecting first cables and a rear net having a curved surface shape that includes a plurality of grids sectioned by a plurality of intersecting second cables, a mesh configured to cover the plurality of grids of the front net from a lower part of the front net, a node cover configured to cover nodes of the front net from an upper part of the mesh and to receive the plurality of first cables at the nodes of the front net and a protruded portion generated by the nodes of the front net, a node body configured to be connected with the node cover disposed at the upper part of the mesh from a lower part of the mesh, and a tension tie connection unit configured to be connected with the node body and also connected with tension ties determining a distance between the rear net and the front net. 
         [0014]    The node cover may include a plurality of recesses to receive the plurality of first cables such that the plurality of first cables are guided at a predetermined angle from the respective nodes of the front net. 
         [0015]    The node cover may include a hole disposed in a center to receive the protruded portion generated as the plurality of first cables overlap at the nodes of the front net. 
         [0016]    The tension ties may be connected with the tension tie connection unit having a hook form and include an elastic medium disposed in a center. 
         [0017]    The cable network antenna may further include a circumferential truss to support the front net, the rear net, and the tension ties to achieve a deployment mechanism of the cable network antenna. 
         [0018]    According to an aspect of the present invention, there is also provided a cable network antenna including a front net having a curved surface shape that includes a plurality of grids sectioned by a plurality of intersecting first cables and a rear net having a curved surface shape that includes a plurality of grids sectioned by a plurality of intersecting second cables, a mesh configured to cover the plurality of grids of the front net from an upper part of the front net, a node body configured to receive the nodes of the front net from a lower part of the mesh, a node cover configured to receive a protruded portion generated by the nodes of the front net from an upper part of the mesh and to be connected with the node body with the mesh interposed between the node cover and the node body, and a tension tie connection unit configured to be connected with the node body and also connected with tension ties determining a distance between the rear net and the front net. 
         [0019]    The node cover may include a hole disposed in a center to receive the protruded portion generated as the plurality of first cables overlap at the nodes of the front net. 
         [0020]    The node body may include a plurality of recesses to receive the plurality of first cables such that the plurality of first cables are guided at a predetermined angle from the respective nodes of the front net. 
         [0021]    The tension ties may be connected with the tension tie connection unit having a hook form and include an elastic medium disposed in a center. 
         [0022]    The cable network antenna may further include a circumferential truss configured to support the front net, the rear net, and the tension ties to achieve a deployment mechanism of the cable network antenna. 
       EFFECT 
       [0023]    According to embodiments of the present invention, nodes at which a plurality of cables intersect may be maintained in correct positions and, therefore, an accurate reflecting surface may be maintained. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    These and/or other aspects, features, and advantages of the invention will become apparent and more readily appreciated from the following description of exemplary embodiments, taken in conjunction with the accompanying drawings of which: 
           [0025]      FIG. 1  is a diagram illustrating a structure of a deployable cable network antenna of a circumferential truss type, according to an embodiment of the present invention; 
           [0026]      FIG. 2  is a diagram illustrating nodes formed at the front net or the rear net, seen from above, in the antenna structure of  FIG. 1 ; 
           [0027]      FIG. 3  is an assembly diagram illustrating a node fixing unit of a cable network antenna according to an embodiment of the present invention; 
           [0028]      FIG. 4  is an exploded view of  FIG. 3 ; 
           [0029]      FIG. 5  is a diagram illustrating a cable network antenna in which a plurality of cables and a node cover are assembled, according to an embodiment of the present invention; 
           [0030]      FIG. 6  is a diagram illustrating a cable network antenna in which a mesh, a node body, and a tension tie connection unit are assembled, according to an embodiment of the present invention; 
           [0031]      FIG. 7  is a diagram illustrating a cable network antenna according to another embodiment of the present invention; and 
           [0032]      FIG. 8  is a diagram illustrating a cable network antenna according to still another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Exemplary embodiments are described below to explain the present invention by referring to the figures. 
         [0034]      FIG. 1  is a diagram illustrating a structure of a deployable cable network antenna of circumferential truss type, according to an embodiment of the present invention. In  FIG. 1 , an upper drawing is a perspective view of a cable network deployable antenna and a lower drawing is a side view of the cable network deployable antenna according to the embodiment of the present invention. Hereinafter, the cable network deployable antenna will be referred to simply as ‘network antenna.’ 
         [0035]    Referring to  FIG. 1 , the network antenna may include a circumferential truss  110 , a front net  120 , a rear net  130 , and a tension tie  140 . 
         [0036]    The circumferential truss  110  functions as a support structure that supports the front net  120 , the rear net  130 , and the tension tie  140 , so as to achieve a deployment mechanism of the network antenna. That is, the front net  120  and the rear net  130  may be deployed or folded by the circumferential truss  110 . The circumferential truss  110  may also control tension of the tension tie  140 . Therefore, a user may reduce size of the network antenna or easily move and store the network antenna, using the circumferential truss  110 . 
         [0037]    The front net  120  may form a curved reflective surface to reflect waves. The front net  120  includes a plurality of grids sectioned by a plurality of intersecting first cables. That is, the plurality of first cables constructing the front net  120  may generate the plurality of grids by intersecting one another. The front net  120  including the plurality of grids may be shaped as a curved surface like a wide dish. Here, waves are reflected by the curved reflective surface. 
         [0038]    The rear net  130  may also form a curved reflective surface and include a plurality of grids sectioned by a plurality of intersecting second cables. In the same manner as in the front net  120 , the plurality of second cables constructing the rear net  130  may form the plurality of grids by intersecting one another. 
         [0039]    The rear net  130  may be disposed symmetrically to the front net  120  to apply pre-tension to the front net  120 . 
         [0040]    The front net  120  and the rear net  130  are disposed symmetrically to each other. Nodes of the front net  120  and nodes of the rear net  130  are interconnected by the tension tie  140 . 
         [0041]    The tension tie  140  may connect nodes of the front net  120  and the rear net  130 , symmetrically corresponding to each other, and apply the pre-tension to the front net  120  and the rear net  130 . The nodes will be described with reference to  FIG. 2 . 
         [0042]    Each of the cables constructing the front net  120  and the rear net  130  may be in the form of a thin band having a rectangular cross section. The front net  120  and the rear net  130  may be made of a light material having a high elasticity coefficient, such as Kevlar. That is, the front net  120  and the rear net  130  are rigid bodies in comparison to the tension tie  140 . 
         [0043]    Cables of the front net  120  and the rear net  130  may be in the form of the thin band having a rectangular cross section so that overlapping portions of the cables are as flat as possible. Here, for convenience and accuracy in manufacturing, the cables may be provided in a minimum number without being cut. That is, the cables may extend from one end of the circumferential truss  110  up to the opposite end without being cut. 
         [0044]    A tension tie connection unit  370  ( FIG. 3 ) may be connected to both ends of the tension tie  140 . Therefore, the nodes of the front net  120  and the rear net  130  may be connected with the tension tie  140 . 
         [0045]    The tension tie  140  may be connected with the nodes of the front net  120  and the rear net  130  through the tension tie connection unit having a form of a hook. In this instance, a center of the tension tie  140  may include an elastic medium such as a spring. 
         [0046]    The tension tie  140  may be slightly shorter than distances between the nodes of the front net  120  and corresponding nodes of the rear net  130 , so as to interconnect and apply pre-tension to the front net  120  and the rear net  130 . 
         [0047]      FIG. 2  is a diagram illustrating nodes  210  formed at the front net or the rear net, as seen from above, in the antenna structure of  FIG. 1 . 
         [0048]    The nodes  210  of the front net and the rear net refer to positions in which the plurality of cables intersect. For example, when three cables intersect, the node among the three cables may have angles of about 60°. The nodes  210  need to be disposed on an ideal curved reflective surface in the network antenna. In particular, the nodes  210  need to be disposed in accurate positions on the curved reflective surface when the network antenna is in a deployed state. 
         [0049]    Accordingly, positions of the plurality of cables constructing the nodes  210  need to be accurate. Even after the front net and the rear net are constructed and an external load such as the pre-tension is applied, the positions of the nodes  210  need to be maintained. 
         [0050]    In particular, when the network antenna is deployed, some force may be applied to the nodes  210  through the tension tie. Here, if the cables constructing the nodes  210  slip relative to each other, the nodes  210  may be displaced. That is, such displacement is to be prevented. 
         [0051]    Therefore, a node fixing unit as shown in  FIG. 3  may be employed to form the nodes  210  more securely and accurately. 
         [0052]      FIG. 3  is an assembly diagram illustrating a node fixing unit  300  of a network antenna according to an embodiment of the present invention.  FIG. 4  is an exploded view of  FIG. 3 . 
         [0053]    The network antenna may include a front net that includes a plurality of first cables  320 ,  330 , and  340 , a rear net, a mesh  350 , a tension tie, a circumferential truss, and the node fixing unit  300  including a node cover  310 , a node body  360 , and the tension tie connection unit  370 . 
         [0054]    The foregoing descriptions of  FIGS. 1 to 2  may be referred to with respect to the front net, the rear net, and the circumferential truss. Hereinafter, the node fixing unit  300  will be described in detail. 
         [0055]    The node cover  310  may cover each of the nodes of the front net from an upper part of the mesh  350 . Also, the node cover  310  may receive a plurality of first cables, that is, the cable  1   320 , the cable  2   330 , and the cable  3   340 , at the nodes of the front net. The node cover  310  may be provided to every node of the front net and the rear net. 
         [0056]    The node cover  310  may include a plurality of recesses  305  to receive the plurality of cables  320 ,  330 , and  340  such that the plurality of cables are guided at a predetermined angle from the nodes of the front net. 
         [0057]    The mesh  350  may cover a plurality of grids of the front net from a lower part of the front net constructed by the plurality of cables  320 ,  330 , and  340 . 
         [0058]    The node body  360  may include a hole  365  to receive a protruded portion generated as the plurality of cables overlap at the node. The node body  360  may be connected with the node cover  310  disposed at the upper part of the mesh  350 , from a lower part of the mesh  350 . 
         [0059]    The tension tie connection unit  370  may be connected to the node body  360  and also connected to respective tension ties (not shown) maintaining tension between the rear net and the front net. 
         [0060]      FIG. 5  is a diagram illustrating a network antenna in which a plurality of cables  510  and a node cover  520  are assembled, according to an embodiment of the present invention. 
         [0061]    Referring to  FIG. 5 , the plurality of cables  510  are sequentially superposed on a node cover  520  which is in an upside-down position. The node cover  520  may include a plurality of recesses  525  to receive the plurality of cables  510  such that each of the cables  520  is guided at a predetermined angle from each node of the front net. 
         [0062]    The plurality of cables  510  and the node cover  520  may be assembled in the following manner. 
         [0063]    First, correct positions of the nodes are marked on the plurality of cables  510 . The marked portions of the plurality of cables  510  are disposed in a center of the node cover  520 . Next, the plurality of cables  510  are inserted in the recesses  525  of the node cover  520 . Here, an adhesive may be applied between the node cover  520  and the plurality of cables  510  to securely fix the plurality of cables  510  to the node cover  520 . 
         [0064]      FIG. 6  is a diagram illustrating a network antenna in which a mesh  610 , a node body  620 , and a tension tie connection unit  630  are assembled, according to an embodiment of the present invention. 
         [0065]    The node body  620  may be attached to a predetermined position on a lower portion of the mesh  610  by an adhesive or the like. The node body  620  may include a hole  625  to receive an overlapping portion of three cables, that is, a protruded portion generated in a center as a plurality of cables overlap at the node of the front net. Here, the protruded portion is protruded from the node cover connected with the node body  620 . 
         [0066]    In addition, the tension tie connection unit  630  may be connected to one side of the node body  620 , opposite to a side connected with the mesh  610 , to hook the tension tie. 
         [0067]    The front net or the rear net may be constructed by bonding the node cover of  FIG. 5  to corresponding portions of the node body  620  of  FIG. 6  by an adhesive. 
         [0068]    Here, the mesh  610  is cut into a plane surface, maintaining an outline as shown in to  FIG. 2 . The front net and the rear net constructed by the plurality of cables are formed as the curved surface as shown in  FIG. 1 . Accordingly, when the mesh  610  is connected with the front net or the rear net, the plurality of cables are separated from the mesh  610  except at the nodes. 
         [0069]      FIG. 7  is a diagram illustrating a network antenna according to another embodiment of the present invention. 
         [0070]    The network antenna may include a front net that includes a plurality of cables  720 ,  730 , and  740 , a rear net, a mesh  750 , a tension tie, a circumferential truss, and a node fixing unit  700  including a node cover  710 , a node body  760 , and a tension tie connection unit  770 . 
         [0071]    Here, the foregoing descriptions of  FIGS. 1 to 2  may be referred to with respect to the front net, the rear net, and the circumferential truss. Hereinafter, the node fixing unit  700  will be described in detail. 
         [0072]    The node cover  710  may cover each of the nodes of the front net from an upper part of the mesh  750 . Also, the node cover  710  may receive, at each node of the front net, a protruded portion generated by each of the plurality of cables  720 ,  730 , and  740  and each of the nodes of the front net. 
         [0073]    The node cover  710  may include a plurality of recesses  715  to receive the plurality of cables  720 ,  730 , and  740  such that the plurality of cables  720 ,  730 , and  740  are guided at a predetermined angle from the nodes of the front net. 
         [0074]    When the front net or the rear net is assembled as shown in  FIG. 7 , a protruded portion at which the three cables overlap may be protruded toward the node cover  710 . A hole  705  may be provided to the node cover  710  to receive the protruded portion. 
         [0075]    In other words, the node cover  710  may include the hole  705  disposed in a center to receive the protruded portion generated as the plurality of cables  720 ,  730 , and  740  overlap at each node of the front net. 
         [0076]    The mesh  750  may cover a plurality of grids of the front net from a lower part of the front net. 
         [0077]    The node body  760  may be connected to the node cover  710  from a lower part of the mesh  750 . Here, the node cover  710  is disposed on an upper portion of the mesh  750 . 
         [0078]    The tension tie connection unit  770  may be connected to the node body  760 , and also connected to tension ties (not shown) maintaining tension between the rear net and the front net. Each of the tension ties may be connected to the tension tie connection unit  770  having a hook form and may include an elastic medium such as a spring disposed in a center. 
         [0079]      FIG. 8  is a diagram illustrating a network antenna according to still another embodiment of the present invention. 
         [0080]    The network antenna may include a mesh  820 , a front net that includes a plurality of cables  830 ,  840 , and  850 , a rear net, a tension tie, a circumferential truss, and a node fixing unit  800  including a node cover  810 , a node body  860 , and a tension tie connection unit  870 . 
         [0081]    Here, the foregoing descriptions of  FIGS. 1 to 2  may be referred to with respect to the front net, the rear net, and the circumferential truss. Hereinafter, the node fixing unit  800  will be described in detail. 
         [0082]    The node cover  810  may receive a protruded portion generated by each node of the front net at an upper part of the mesh  820 . The node cover  810  is connected with the node body  860  with the mesh  820  interposed. 
         [0083]    In addition, the node cover  810  may include a hole  805  disposed in a center to receive the protruded portion generated as the plurality of cables  830 ,  840 , and  850  overlap at each node of the front net. 
         [0084]    The node body  860  may receive each of the nodes from a lower part of the mesh  820 . The node body  860  may include a plurality of recesses  865  to receive the plurality of cables  830 ,  840 , and  850  such that the plurality of  830 ,  840 , and  850  are guided at a predetermined angle from the nodes of the front net. 
         [0085]    The tension tie connection unit  870  may be connected to the node body  860  and also connected to tension ties (not shown) maintaining tension between the rear net and the front net. Each of the tension ties may be connected to the tension tie connection unit  870  having a hook form and may include an elastic medium disposed in a center. 
         [0086]    A method of manufacturing the front net and the rear net, using the node fixing unit, will now be described. 
         [0087]    First, the plurality of cables  830 ,  840 , and  850  marked with positions of the nodes are disposed at correct positions on the front net and the rear net, and bonded by an adhesive. The node cover  810  is bonded to a predetermined position on the mesh  820 . 
         [0088]    The two assemblies, that is, the node cover  810  and the node body  860 , are bonded to each other using an adhesive. In this case, since the plurality of cables  830 ,  840 , and  850  are received in the recesses  865  formed at the node body  860 , the mesh  820  needs to be disposed at an upper part of the plurality of cables  830 ,  840 , and  850 . 
         [0089]    In this case, due to the protruded portion generated as the plurality of cables  830 ,  840 , and  850  overlap, the mesh  820  may also form a protruded portion. Although the protruded portion of the mesh  820  has a minor height, the embodiments described with reference to  FIGS. 4 to 7  may be applied in case of an ultrahigh frequency antenna which requires high surface accuracy. 
         [0090]    After manufacturing the front net and the rear net in the foregoing method, when the tension tie and the circumferential truss are prepared, the network antenna may be assembled in the following manner. 
         [0091]    The circumferential truss is fully deployed. The front net and the rear net are connected to the circumferential truss. Next, the nodes of the front net and the nodes of the rear net are interconnected by the tension tie. Accordingly, the meshes of the front net and the rear net are extended, thereby forming the curved surfaces as shown in  FIG. 1 . 
         [0092]    Although a few exemplary embodiments of the present invention have been shown and described, the present invention is not limited to the described exemplary embodiments. Instead, it would be appreciated by those skilled in the art that changes may be made to these exemplary embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.