Patent Publication Number: US-7898497-B2

Title: Enclosed reflector antenna mount

Description:
BACKGROUND 
     1. Field of the Invention 
     This invention relates to reflector antenna mounts. More particularly, the invention relates to a cost efficient enclosed reflector antenna mount with improved visual aesthetics, electrical performance and alignment characteristics 
     2. Description of Related Art 
     Terrestrial reflector antennas are used, for example, in communications systems to provide point to point communications links. Conventional reflector antennas apply a radome to provide environmental protection to the antenna feed and reflector dish surface, the radome extending across the reflector dish face. A conventional terrestrial reflector antenna is typically aligned with the signal source and/or desired receiver by orienting the entire reflector assembly at the antenna support connection(s) to the mounting point, for example a radio tower or mast. 
     A radome introduces an electrical discontinuity and thereby a signal reflection surface into the signal path. Radome configurations with surfaces that are angled with respect to the signal path direct reflected signal components away from the signal path to reduce return losses. U.S. Utility Pat. No. 7,042,407, issued May 9, 2006, titled “Dual Radius Twist Lock Radome and Reflector Antenna for Radome”, by Syed et al, hereby incorporated by reference in the entirety, discloses a radome with a large radius of curvature within the antenna signal path and a smaller radius of curvature in the central area of the radome generally within the subreflector shadow. 
     Terrestrial reflector antenna radomes are typically limited to the reflector front face only, to avoid the greatly increased overall volume of a radome sized to enclose the full range of movement of the entire antenna assembly, such as a spherical or hemispherical enclosure. Further, full enclosure radomes also require substantially stronger mounting and support configurations because of the vastly increased wind loads a larger radome will encounter. 
     In some locations, such as residential and or nature preserve areas, installation of reflector antenna equipment may be subject to significant public opinion resistance, building codes and or neighborhood regulations due to a negative perception of the visual impact that antenna(s) and associated communications equipment may introduce to previously clear vistas. 
     Competition within the terrestrial reflector antenna industry has focused attention on RF signal pattern optimization, structural integrity, as well as materials and manufacturing operations costs. Also, increased manufacturing efficiencies, via standardized reflector antenna components usable in configurations adaptable for multiple frequency bands, are a growing consideration in the reflector antenna market. 
     Therefore, it is an object of the invention to provide an apparatus that overcomes deficiencies in the prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a schematic front view of an exemplary enclosed reflector antenna mount shown in combination with a second antenna enclosure, a cellular base station antenna. 
         FIG. 2  is a schematic isometric view of the enclosed reflector antenna mount of  FIG. 1 . 
         FIG. 3  is a schematic isometric cross section view of the reflector antenna mount along line D-D of  FIG. 1 . 
         FIG. 4  is a schematic isometric cross section view of the reflector antenna mount along line E-E of  FIG. 1 . 
         FIG. 5  is a schematic isometric view of a reflector antenna mount with the enclosure removed. 
         FIG. 6  is a schematic front of the  FIG. 5  reflector antenna mount. 
         FIG. 7  is a schematic side view of the  FIG. 5  reflector antenna mount. 
         FIG. 8  is a front view of an antenna enclosure front face. 
         FIG. 9  is an isometric view of the front face and transitions to sidewalls of  FIG. 8 . 
         FIG. 10  is a top cross-section view taken along line A-A of  FIG. 8 . 
         FIG. 11  is an isometric view of an enclosure with the front face of  FIG. 8 . 
         FIG. 12  is a front view of an antenna enclosure front face with a center portion. 
         FIG. 13  is an isometric view of the front face and transitions to sidewalls of  FIG. 12 . 
         FIG. 14  is a top cross-section view taken along line B-B of  FIG. 12 . 
         FIG. 15  is an isometric view of an enclosure with the front face of  FIG. 12 . 
         FIG. 16  is a front view of an antenna enclosure front face with an extended center portion. 
         FIG. 17  is an isometric view of the front face and transitions to sidewalls of  FIG. 16 . 
         FIG. 18  is a top cross-section view taken along line C-C of  FIG. 16 . 
         FIG. 19  is an isometric view of an enclosure with the front face of  FIG. 16 . 
         FIG. 20  is schematic front isometric view of a plurality of reflector antenna mounts coupled together. 
     
    
    
     DETAILED DESCRIPTION 
     The inventors have recognized that a key aspect of public visual aesthetics resistance to installation of terrestrial reflector antennas is the traditional open configuration of a conventional reflector, radome, transceiver and mounting structure. Further, the inventors have recognized that the size of an aesthetically improved reflector antenna enclosure can be significantly reduced when the enclosure rotates with the antenna and antenna mount on one of the two axis of travel. 
     As shown in  FIGS. 1-7 , an exemplary embodiment of an enclosed reflector antenna mount  5  has a primary mount  7  coupled to a support arm  9 . The primary mount  7  is rotatable in a first axis with respect to the support arm  9 . In the present configuration, the first axis is the horizontal or azimuth axis. The primary mount  7  supports a secondary mount  11  pivotable in a second axis. In the present configuration, the second axis is the vertical or elevation axis. The reflector antenna  13  is mounted upon the secondary mount  11 , the reflector base  15  on a front side  17  and an electronics enclosure  19 , for example a transceiver, receiver and or transmitter, extending from the back side  21 . In alternative embodiments, the electronics enclosure  19  may be omitted and signals from the reflector antenna routed to a remote location for further processing, for example via a waveguide and or coaxial cable. 
     The rotatable connection between the support arm  9  and the primary mount  7 , best shown in  FIGS. 5-7 , may be configured, for example, as a plurality of primary slot(s)  23  in the support arm  9  formed as arc segments having a common primary centerpoint  25 . Primary fastener(s)  27  through the primary slot(s)  23 , coupled to the primary mount  7 , enable rotation of the primary mount  7  with respect to the support arm  9  through the extent of the primary slot(s)  23 . A primary threaded rod  29  pivotably supported by the support arm  9  may be configured to thread in and out of a primary axis block  31  coupled to one of the primary fastener(s)  27 , thus driving the rotation of the primary mount  7  through the range of motion with a high degree of precision via rotation adjustments to the primary threaded rod  29 . Once the desired orientation in the primary axis is set, the primary mount  7  may be locked in place by tightening the primary fastener(s)  27 . 
     The pivotable connection between the primary mount  7  and the secondary mount  11  may use a similar arrangement of secondary fastener(s)  33  in at least one secondary slot(s)  35  with an arc configuration arranged about a secondary centerpoint  37 . A secondary threaded rod  39  pivotably supported by the primary mount  7  may be configured to thread in and out of a secondary axis block (not shown) coupled to one of the secondary fastener(s)  33 , thus driving the rotation of the secondary mount  11  through the range of motion with a high degree of precision via rotation adjustments to the secondary threaded rod  39 . Once the desired orientation in the second axis is set, the secondary mount  11  may be locked in place by tightening the secondary fastener(s)  33 . 
     One skilled in the art will appreciate that the arrangement with respect to the location of the primary and secondary slot(s)  23 ,  35  may be reversed in an alternative equivalent structure. That is, the primary and secondary slot(s)  23 ,  35  may be located on the primary mount  7  and secondary mount  11 , respectively, and the respective primary and secondary fastener(s)  27 ,  33  instead coupled to the support arm  9  and primary mount, respectively. 
     An enclosure  43 , best shown in  FIGS. 1 and 2 , coupled to the primary mount  7 , rotates with the reflector antenna mount  5  about the first axis. The enclosure  43  has a front face  45 , and a side surface  47  that wraps about the primary and secondary mount  7 ,  11  periphery. The front face  45  operates as the radome, spaced far enough forward to allow clearance for the reflector antenna  13  range of motion while pivoting through the second axis. 
     As shown in  FIGS. 8-19 , the front face  45  may be configured with a large radius of curvature, for example a radius of curvature at least three times a radius of the reflector antenna, to reduce reflection of signals from the front face  45  back to the subreflector  49  and feed  51 . Further optimization of the contribution of the enclosure  43  to the electrical performance may be achieved by adding a center portion  53 , generally in the shadow of the sub reflector  49 , with a reduced radius of curvature to focus any signal reflections upon this area of the front face  45  upon subreflector RF absorbing material  55  placed on an outer surface of the sub reflector  49  and/or at the area proximate the intersection of the feed  51  with the reflector  57 . To improve the return loss reduction contribution of the reduced radius of curvature center portion  53  throughout the range of motion along the secondary axis, the center portion  53  may be elongated so that when pointed at either extent along the secondary axis, one end or the other of the center portion  53  remains positioned generally in the shadow of the sub reflector  49 . 
     The side surface  47  of the enclosure  43  may be configured with no overhanging edges, enabling cost effective high shape precision manufacturing via, for example, dielectric polymer injection molding or vacuum forming. To minimize introduction of phase errors or the like, the enclosure  43  front face  45  may be configured with a constant material thickness. To reduce the generation of back lobes, the inner side of the enclosure  43  side surface  47  may be configured with side surface RF absorbing material  59 , for example as shown in  FIG. 4 . 
     A back plate  61  may be added to the enclosure  43  to suppress back lobes and or provide an environmental seal of the enclosure  43  around the primary and secondary mounts  7 ,  11 . The back plate  61  may be configured to clear the primary and secondary mounts  7 ,  11  and the electronics enclosure  19  as they move through the extents of the second axis, while leaving space for tool access to the secondary fastener(s)  33 . 
     To provide a streamlined external appearance with respect to a co-mounted antenna such as a cellular base station antenna, other form of panel antenna or additional reflector antenna(s), arranged with a shared mounting associated with the support arm  9 , an adapter cowling  63  may be placed to cover an interconnection gap, if any, between the reflector antenna enclosure  5  and the second antenna enclosure  65  as shown in  FIGS. 1 and 2 . 
     Similarly, the reflector antenna enclosure  5  may be configured with a plurality of other reflector antenna enclosure(s), for example, as shown in  FIG. 20 . Further, although the stacking has been demonstrated as vertical, the multiple antenna enclosures may be aligned in a horizontal configuration, which exchanges the first and second axes. 
     One skilled in the art will recognize that an enclosed reflector antenna mount  5  according to the invention provides improved environmental protection and visual aesthetics without sacrificing electrical performance or unacceptably increasing manufacturing costs. Because the enclosure  43  is sized to accommodate only the internal movement of the reflector antenna  13  along a single arc path, the enclosure  43  may be made smaller and closer fitting than previous terrestrial reflector antenna enclosures. Further, installation is greatly simplified via the primary mounting via the support arm  9  attachment to the selected support structure and later fine tuning of the antenna pointing via easy adjustment of the primary and secondary mounts  7 ,  11 . 
     
       
         
           
               
             
               
                   
               
               
                 Table of Parts 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 5 
                 reflector antenna mount 
               
               
                 7 
                 primary mount 
               
               
                 9 
                 support arm 
               
               
                 11 
                 secondary mount 
               
               
                 13 
                 reflector antenna 
               
               
                 15 
                 reflector base 
               
               
                 17 
                 front side 
               
               
                 19 
                 electronics enclosure 
               
               
                 21 
                 back side 
               
               
                 23 
                 primary slot 
               
               
                 25 
                 primary centerpoint 
               
               
                 27 
                 primary fastener 
               
               
                 29 
                 primary threaded rod 
               
               
                 31 
                 primary axis block 
               
               
                 33 
                 secondary fastener 
               
               
                 35 
                 secondary slot 
               
               
                 37 
                 secondary centerpoint 
               
               
                 39 
                 secondary threaded rod 
               
               
                 43 
                 enclosure 
               
               
                 45 
                 front face 
               
               
                 47 
                 side surface 
               
               
                 49 
                 subreflector 
               
               
                 51 
                 feed 
               
               
                 53 
                 center portion 
               
               
                 55 
                 subreflector RF absorbing material 
               
               
                 57 
                 reflector 
               
               
                 59 
                 side surface RF absorbing material 
               
               
                 61 
                 back plate 
               
               
                 63 
                 adapter cowling 
               
               
                 65 
                 second antenna enclosure 
               
               
                   
               
            
           
         
       
     
     Where in the foregoing description reference has been made to ratios, integers, components or modules having known equivalents then such equivalents are herein incorporated as if individually set forth. 
     While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant&#39;s general inventive concept. Further, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.