Patent Publication Number: US-6222502-B1

Title: Antenna mounting enclosure

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to directional antennas and radio communications, and more particularly to an apparatus for mounting directional antennas. 
     Wireless telecommunications systems utilize radio signals to exchange information between fixed-wire base stations and free-standing mobile stations. In cellular communications applications, for example, each base station transmits from an antenna over a fixed-area range called a “cell.” In order to provide service to mobile telephones over a large geographic area, many cells are positioned over the area to provide complete coverage. 
     In typical cellular configurations, base station antennas create large, hexagonal or circular-shaped macrocells with the main antennas located at the center of the cell. The transmissions from the base station ideally propagate outward 360 degrees from the antennas. These cells are often referred to as “omni-directional.” These omni-directional cells require the base station antennas to be mounted in an array that allows them to be pointed in a plurality of directions to provide 360 degrees of coverage. In order to provide this wide range of unobstructed coverage, the antennas must be mounted in a clear area, often located high above the ground on antenna towers. 
     In most cellular applications in densely occupied urban areas, the cellular antennas are mounted more closely to street level on towers projecting from the rooftops of buildings. These towers have proven to be unsightly, especially where the towers mount several antennas and their associated circuitry, cabling and other necessary equipment within the plain view of persons on the ground. The unsightliness of these structures can result in the unwillingness of building owners to allow necessary cellular antennas to be installed on their buildings. 
     Therefore, there is a need for an improved apparatus for mounting directional antennas and related equipment in a fashion that allows omni-directional propagation while maintaining a pleasant appearance. 
     SUMMARY OF THE INVENTION 
     The present invention provides an apparatus for mounting a plurality of antennas via a convenient, visibly pleasing, self-contained structure. The present invention may be embodied in an apparatus that includes an enclosure having three adjoining side walls defining an interior space. Each of the walls includes an exterior surface and means on the exterior surfaces for mounting a plurality of antennas to the walls. The enclosure defines at least one opening to allow access to the interior space. The antennas may thus be mounted to the enclosure to be pointed in at least three opposing directions approximately 120° apart to provide 360°, omni-directional coverage. The interior space of the enclosure provides a convenient weatherproof area to store support equipment for operation of the antennas. 
     In another aspect of the invention, each of the three main side walls of the enclosure are positioned approximately 120° to each other, thereby creating a structure having a horizontal cross-section corresponding to an equilateral triangle. The upstanding walls allow sets of antennas to be mounted along each wall and pointed in a direction generally perpendicular to the plane of each wall. This allows a 360° range of coverage for the antennas arrayed on the apparatus. 
     In another aspect of the invention, the apparatus is adapted for positioning on a rooftop in an unobtrusive fashion. The upstanding walls of the structure allow for camouflaging and provide a convenient enclosed space for enclosing and mounting electronic support equipment and cables out of sight. 
     The present invention may be further embodied in an apparatus that includes mounting means to allow antennas to be mounted to the enclosure along at least three planes angled approximately 120 degrees to each other. This structure allows antennas to be mounted to an enclosure having a variety of shapes. 
     Thus, the present invention provides a convenient apparatus for inconspicuously mounting directional antennas. The present invention may be used to mount antennas such as directional cellular antennas to the rooftops of buildings or other vertical structures, while providing an area for storage and mounting of related support equipment within the apparatus. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. The invention, together with further objects and attendant advantages, will best be understood by reference to the following detailed description, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a perspective view of the preferred embodiment of the present invention. 
     FIG. 2 shows an enlarged side view of the preferred embodiment of the invention of FIG.  1 . 
     FIG. 3 shows a top view of the preferred embodiment of the invention of FIG.  1 . 
     FIG. 4 shows a perspective view of the preferred embodiment of FIGS. 1 and 2 including mounted antennas and related hardware. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a perspective view of the preferred embodiment of the enclosure apparatus  10 . Taken in conjunction with the side and top views shown at FIGS. 2 and 3, the enclosure  10  includes upstanding side walls  12 ,  14  and  16 . Preferably, each of the walls  12 ,  14  and  16  meets with an adjacent wall at an angle of approximately 120°, thereby forming an enclosure having cross-section similar to an equilateral triangle. A unitary, triangular roof structure  17  having a slightly domed configuration is mounted over the walls  12 ,  14  and  16 . 
     In the preferred embodiment, side wall  14  defines an opening or doorway  18  to allow passage into the interior of the enclosure  10 . Doorway  18  may be sealably closed by a door  20  mounted to the wall  14  by hinges  24 . Preferably, the door is tall enough for a person to comfortably pass through. The door  20  also preferably includes a latch  22  of conventional design. 
     In the preferred embodiment, a fiberglass, molded composite laminate is used to form the walls  12 ,  14  and  16  of the enclosure  10 . Preferably, the composite material is approximately 1½ inches thick. The interior of the walls also preferably are covered with ¾-inch polyurethane insulating foam sheeting. The floor of the enclosure  10  preferably comprises an 18-gauge steel sheeting base and a cover layer of ¾-inch plywood. This material is weatherproof and lightweight, yet strong enough to support the mounting of heavy antenna hardware. Additional stability at the joints between walls  12 ,  14  and  16  may be added by mounting reinforced corner braces  40 . The exterior dimensions of the preferred embodiment of the enclosure  10  are preferably 12 feet wide for each of walls  12 ,  14  and  16 , and  11  feet in height. In the alternative, the walls  12 ,  14  and  16 , the door  20 , and roof  17  preferably may also be constructed from sheet metal approximately 18-gauge. 
     The enclosure  10  may be mounted to rooftop surfaces via mounting brackets  30 . The brackets  30  can receive mounting bolts (not shown) to hold the brackets  30  and the enclosure  10  flush to the rooftop surface. 
     A possible configuration of the enclosure  10  incorporating antenna hardware and related equipment is illustrated in FIG.  4 . As shown in the figure, three directional cellular antennas  50  are mounted on each of the side walls  12 ,  14  and  16  via mounting brackets  52 . The brackets  52  can be of a structure known to those skilled in the art as sufficient to mount various forms of antennas. Each of the antennas  50  are positioned in this embodiment to be pointing slightly downwardly as shown. This configuration provides improved cellular range on the ground when the enclosure  10  is mounted to a high surface such as a rooftop. 
     Miscellaneous hardware, such as the power boxes  60  and electrical switchboxes  62 , may be mounted to the walls  12 ,  14  and/or  16  of the enclosure  10  as shown in FIG.  4 . The walls may be drilled and grommetted to provide weatherproof passage means as shown for cables  64  to link the exterior surfaces of the walls  12 ,  14  and  16  with the interior of the enclosure  10 . Other electrical or antennas support equipment may be stored inside the enclosure  10  to shield the equipment from weather. 
     The preferred embodiment provides 360° of coverage for cellular antennas with the 120° angled wall configuration shown. However, other configurations may be appropriate while remaining within the scope of the invention. For example, the walls  12 ,  14  and  16  may not necessarily define an equilateral triangle, but may define an irregular triangular structure to more attractively blend in with architecture or surroundings of a particular rooftop. The three angled main walls  12 ,  14  and  16  will still provide a wide range of coverage. Furthermore, variously shaped mounting brackets may be utilized to mount the antennas  50  to the structure so that the antennas  50  mounted in an array on the enclosure  10  may be pointing in various directions to provide 360° of coverage. In the alternative, the three main walls  12 ,  14  and  16  may be separated by other spacing walls rather than meeting at the corners to produce a triangle. Thus, a triangular structure such as in the preferred embodiment is not necessary to provide 360° of coverage, and various shapes may be utilized. 
     The enclosure of the present invention advantageously provides a secure, stable and convenient structure on which to mount antennas and related equipment. The structure also encloses and hides unsightly equipment and may be further camouflaged with paint or other materials to make a more attractive enclosure. Furthermore, the contained structure of the enclosure can be easily pre-manufactured off-site and pre-fitted with the antennas. This greatly simplifies installation on building locations. 
     Of course, it should be understood that a wide range of changes and modifications can be made to the preferred embodiments described above. For example, the enclosure described herein should not be limited to the precise structure and orientation shown in the drawings and described in the specification. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it be understood that it is the following claims, including all equivalents, which are intended to define the scope of this invention.