Abstract:
A cellular communication antenna has a base with a length that exceeds its width and an inside surface with internal mounts for a plurality of electrical components that generate heat when in operation. A top encapsulates the electrical components and incorporates a radome. A plurality of fins are mounted on the outside surface of the base. They may be non-parallel with the length of the base. They may all be substantially the same length. They are further constructed and arranged to be in thermal communication with the electrical components such that heat generated by the electrical components is dissipated by the fins. Each fin may be in thermally conductive communication with more than one electrical component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/119,224 filed on Dec. 2, 2008 and to U.S. Provisional Application No. 61/119,270, also filed on Dec. 2, 2008. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is in the field of cellular radio frequency communication system antennas and in particular heat dissipation from them. 
         [0004]    2. Related Art 
         [0005]    Antennas for cellular radio frequency communication systems, for example cellular telephone antennas, are advantageously arranged in configurations having a length that substantially exceeds the width of the antenna. A typical antenna may be two meters long and 30 centimeters wide. These antennas are usually mounted so that their long axis is substantially vertical. They are most frequently mounted on a cell phone tower that is often as high as 200 feet. 
         [0006]    The antennas contain electrical components including modular radios, power supplies and/or transformers, radio frequency emitters and other components. In operation, these components generate heat. This heat should be dissipated in order to keep the operating electrical components at an advantageous temperature for effective and durable operation. 
         [0007]    The antennas usually have a radome on one side. The antennas are typically mounted with the radome outermost, and with a back surface of the antenna facing the tower, as well as other structure, antennas and equipment that may also be mounted on the tower. 
         [0008]    Active cooling components such as fans are problematic to install high on antenna towers, and so it is desirable to dissipate heat from antennas by passive means. Preexisting designs mounted heat dissipating fins on the back of the antenna. However, these fins were vertically aligned along the length of the antenna. Air heated by the components in the lower portion of the antenna would rise along the fins. The upper portions of the fins receiving this pre-heated air could not transfer heat from the upper components of the antenna efficiently. Further complicating considerations include the presence of the antenna in the open air during normal operations and the orientation of the heat exchanging (back) surface of the antenna towards the tower structure and other equipment mounted there. Of course, economy and the fabrication of components remains a consideration. 
       SUMMARY OF THE INVENTION 
       [0009]    A cellular communication antenna has a base with a length that exceeds its width and an inside surface with internal mounts for a plurality of electrical components that generate heat when in operation. A top encapsulates the electrical components and incorporates a radome. A plurality of fins are mounted on the outside surface of the base. They may be non-parallel with the length of the base. They may all be substantially the same length. They are further constructed and arranged to be in thermal communication with the electrical components such that heat generated by the electrical components is dissipated by the fins. Each fin may be in thermally conductive communication with more than one electrical component. Fins may be arranged in groups, and separated by gaps. The gaps may include baffles. 
         [0010]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a rear perspective view of the antenna of the present invention. 
           [0013]      FIG. 2  is a front perspective view. 
           [0014]      FIG. 3  is a top perspective view of the base of the antenna of the present invention. 
           [0015]      FIG. 4  is a top perspective view of the base of the antenna of the present invention. 
           [0016]      FIG. 5  is a top perspective view of the base of the antenna of the present invention. 
           [0017]      FIG. 6  is a top perspective view of the base of the antenna of the present invention. 
           [0018]      FIG. 7  is a perspective view of the fins of an alternate embodiment. 
           [0019]      FIG. 8  is a perspective view of the fins of an alternate embodiment. 
           [0020]      FIG. 9  is a perspective view of the fins of an alternate embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0022]    Referring now to the drawings wherein like reference numbers indicate like elements, Cellular telephone antenna  10  includes a curved, front radome  12  and a rear housing back  14 . The radome and back maintain a space therebetween in which electrical antenna components are mounted.  FIG. 1  is a rear perspective view of the antenna  10  of the present invention showing fins  16  mounted on a base that is the outer surface of a housing back  14 .  FIG. 2  depicts the front of the antenna showing a top that includes a radome  12 . 
         [0023]    The cellular communications antenna  10  is dimensioned to have a length L. Electrical components are arranged generally in line along the length L of cellular communications antenna  10 . 
         [0024]    As depicted in  FIG. 1 , each of the plurality of fins has substantially the same length. Each pair of fins defines a space  18  therebetween. Each space has an opening on a lower portion of said space, which is to the left in  FIG. 1 , and an opening on an upper portion which is to the right in  FIG. 1 . These openings are to the side of the antenna. The lower opening provides an entrance for fresh, unheated air into the space  18  between two fins  16  and the upper opening of the space allows an exit for heated air. 
         [0025]    In the depicted embodiment the fins  16  are divided into groups  20  which in  FIG. 1  are parallelograms. Configuring the fin array groups  20  in this shape allows each fin to be the same length, which advantageously allows each space  18  to open to one side and eject heated air to the other side. The fin array groups  20  are separated by spaces  22 . The spaces  22  may be used for mounting the overall panel supporting fins  16  to the base  14 . 
         [0026]    In still air, the configuration of the present invention allows convection to create advantageous air flow through the spaces  18  and between fins  16 . The configuration of the present invention is further advantageous in windy conditions, in that the opening of the spaces to the side of the antenna readily allows ingress of air into all spaces  18  between all fins  16 . 
         [0027]    Each fin is substantially the same length in the depicted embodiment. Each fin is non-parallel to the length of the overall antenna. In the depicted embodiment, the fins are at an angle between about 40 degrees and about 75 degrees from horizontal, thereby allowing convection to cause air to move through the spaces  18  between the fins  16  as the heated air rises. Vertical or near vertical angles are avoided. Fin arrays with spaces that do not open to the side of the antenna are avoided. Thus, the invention avoids air heated in the lower portion of the antenna to disadvantageously enter the space between fins dissipating heat from the top portions of the antenna. 
         [0028]    An interior view of the base  14  is shown without electrical components in  FIG. 3  and shown with only selected electrical components in  FIG. 4 . The mounted perimeter of each group of fins  20  is shown by diagonal lines  24 , in relation to the electrical components whose heat they will serve to dissipate. As can be seen in  FIGS. 4 and 5  each group of fins  20  may be mounted such that the angle and position of the fins may conduct heat away from more than one electrical component mounted within the base. The antenna may be configured so that each individual fin  16  is in thermal communication with more than one electrical component. The electrical components in the antenna will include modular radios, a calibration radio, a calibration hub, a power supply or transformer and the like. There may be a plurality of some of the components, such as the modular radios, within the same antenna. As seen in  FIG. 6 , in the depicted embodiment, modules  26  may be fabricated onto which the electrical components may be mounted. The modules may thereafter be assembled and attached to the base. Accordingly, the configuration depicted herein wherein each diagonal array of fins may conduct heat away from more than one electrical component may alternatively be constructed and arranged such that each array of fins  20  may conduct heat away from more than one module  26  mounting electrical components. The same may be true of an individual fin in alternate embodiments. 
         [0029]    In the embodiment depicted in  FIG. 7 , each array  120  of fins  116  has a plurality of fins separated by a plurality of spaces  118 . The fins are not parallel to the length longitudinal dimension of the cellular communications antenna  110 . In the usual vertical deployment of the antenna  110 , the fins  116 , will be non-vertical. Because hot air rises, air in spaces  118  that is warmed by convection from fins  116  will move in the direction indicated in the figures by arrow A. Cool, fresh air will thereafter enter the spaces  118  from the lower end of spaces, which is to the left in  FIG. 7 . Because the fins  116  are angled, heated air leaving spaces  118  will exit the array and travel away from the antenna  110 . The majority of heated air exiting the spaces will not reenter the next array of the rail, because the angle of the fins  116  will direct the heated air away. 
         [0030]    In the embodiment depicted in  FIG. 7 , the arrays may be separated by a gap or open space  122 . A baffle  130  may be deployed in this gap  122 . This gap  122  and/or baffle  130  allow air heated by a fin array  120  below it to dissipate (to the right in  FIG. 7 ). In this way, fresh unheated air will enter the gap  122  (from the left in  FIG. 7 ) and enter the spaces  118  of the fm array  120  above the gap  122 . 
         [0031]    In a breeze, the opening of spaces  118  and baffles  130  to the side of the fin array allows for moving air to be more readily received into the spaces  118  between fins  116 , thereby further promoting cooling. 
         [0032]    In another embodiment depicted in  FIG. 8 , fins  216  in fm arrays  220  remain vertical. Further, the fm arrays  220  remain spaced apart by a gap  222 . However, within the gaps is a diagonal baffle  230 . Thus, heated air travels substantially vertically in spaces  218  until the heated air exits the fin array, whereupon it is directed not vertically but to the side by baffle  230 . Thus, cool air (from the left in  FIG. 8 ) is received into the bottom of spaces  218  of the fin array  220  above the baffle. 
         [0033]    In a another alternative embodiment depicted in  FIG. 9 , fins  316  and spaces  318  between them are arranged in parallel but in spaced relation to define a central vertical channel  340  therebetween. Baffles  330  are deployed back to back or in a mirror image configuration, forming inverted chevrons. The direction of convection into channel  340  promotes an air current to draw cooler air into the spaces  318 . 
         [0034]    As various modifications could be made to the exemplary embodiments, as described above with reference to the corresponding illustrations, without departing from the scope of the invention, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.