Patent Document

RELATED APPLICATIONS 
     The present invention claims priority from, and is a continuation application of, U.S. patent application Ser. No. 11/687,469 filed Mar. 16, 2007, which is related to, and claims the benefit of U.S. Provisional Patent Application Ser. No. 60/783,654 filed Mar. 17, 2006, all of which are incorporated herein by reference in their entirety for all purposes as if fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, in general, to RADIO Frequency (“RF”) transparent structures and particularly to RF transparent wall structures comprising polyvinyl chloride (“PVC”) material formed to visually conceal high frequency and broadband antennas and other RF sensitive devices. 
     2. Relevant Background 
     High-speed wireless broadband networks and the like continue to grow in popularity and versatility. Consumer interest in such technology has fueled a need to provide uninterrupted service throughout many regions of the United States. Typically wireless services are limited to a relatively short line of sight range from a local antenna, thus the increased demand has fostered a corresponding demand in establishing numerous antenna structures capable of supporting such RF technology. While the demand for such service continues to grow, the tolerance of unsightly antenna structures associated with such a service has been less than forthcoming. To achieve seamless service in many areas, concealed antenna assemblies are placed on rooftops and other structures throughout the United States and other countries. Recent industry consolidation and government bandwidth auctions has limited the number of licensed carriers to a handful of companies, yet their need for local rooftop antennas continues to grow at an exponential rate. These mega-carriers as they are now referred, have recently entered thousands of US cities and rural areas to expand their cellular, broadband and new 4 th  generation wireless technology networks. 
     While the wireless industry expands and upgrades existing networks with new site locations, local Township, City and County municipalities serving these communities are becoming tougher on antenna concealment codes and regulations that prohibit antennas from being mounted on buildings and rooftops without a concealment plan that will blend the resulting structure into the environment. 
     Concealment of antenna structures is typically done to protect the antenna elements from weather or other harsh environments and/or to meet regulatory requirements. In some applications such as the military, antenna structures and the antennas themselves were camouflaged to reduce the likelihood of detection and destruction. While concealment of cellular and other wireless antenna in a civil setting must meet local environmental constraints, the provider of the cellular service faces economic tradeoffs between aesthetically concealing the antennas so as to meet local ordinances and codes while minimizing the detrimental effects of the concealment assembly on signal strength and the functionality of the antenna. 
     Prior antenna concealment assemblies have generally been customized structures typically composed of Fiberglass, Fiberglass Reinforced Plastic (“FRP”), Polyurethane Foam, ABS Plastic and/or other composite material. Them materials have offered a reasonable degree of structural integrity and strength as well as reasonable degree of RF transparency for lower frequency cellular applications. Such customized structures and material choices, when implemented on a pervasive scale, are however, less feasible for higher spectrum broadband and satellite applications due to extreme RF transparency requirements. 
     Architectural and engineering firms typically design custom wireless rooftop sites using steel or similar metallic substances for mating with ballasted frames or structural roof connections from the building. From these connections a frame is constructed to house various antennas. A custom concealment assembly&#39;s frame and skin are normally thereafter attached to this steel antenna frame to conceal the antennas. As mentioned, the structure of these existing concealment products, such as the skeleton and external panels, are typically concealed with relatively thick fiberglass or FRP sheathing products. 
     As demand for cellular and wireless capability continues to grow, so to does the need to install and conceal additional cellular and wireless antennas. A need exists, therefore, to conceal these antennas with a standardized and cost effective concealment assembly that is both economical to produce and install as well as ultra transparent to higher RF used for data rich transmissions. These and other problems recognized in the prior art are addressed by the present invention. 
     SUMMARY OF THE INVENTION 
     Briefly stated, the present invention involves systems and methods for concealing wireless antenna while maintaining RF transparency using ultra-thin materials. The present invention uses a combination of maintenance-free, RF transparent, and structurally rigid prefabricated Polyvinyl Chloride (PVC) members to conceal an antenna structure. A rigid antenna support structure is designed and fabricated to rest on an existing ballasted antenna frame or on two or more existing support foots normally found on a roof or similar structure. The existing antenna support structure, to which the antennas are attached, possess mounting brackets or other direct points of attachment associated with the exterior of the structure configured to accept a plurality of vertical prefabricated support members composed of a substantially RF transparent material. 
     Attached to the vertical support members are a number of substantially RF transparent horizontal support members forming a concealment assembly skeleton. This skeleton, which is attached to the antenna support structure, is, in one embodiment, constructed from hollow PVC extruded material and is prefabricated based on a predetermined design of the antenna support structure for quick and economical on-site assembly. 
     A plurality of RF transparent interlocking PVC panels are connected to the horizontal support members so as to form a wall concealment assembly that conceals the antenna support structure and antennas housed within. The resulting assembly is environmentally and aesthetically pleasing and retains RF transparency so as to not to attenuate the signals being sent to, or originating from, the antennas. 
     Additional advantages of the present invention will be set forth in the description which follows and will be obvious from the description, or may be learned by practice of the invention. The advantage of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive to the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aforementioned and other features and objects of the present invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of a preferred embodiment taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  shows a perspective view of a cellular antenna support structure possessing mounting fixtures for a prefabricated concealment assembly according to one embodiment of the present invention; 
         FIG. 2  shows a perspective view of the cellular antenna support structure for a prefabricated concealment assembly showing one orientation of antenna components in comparison to vertical support members of the concealment assembly according to one embodiment of the present invention; 
         FIG. 3  shows a side and top view of a cellular antenna concealment assembly  100  according to one embodiment of the present invention; and 
         FIG. 4  shows side and top view of the joining and attaching mechanisms and orientation of support members of a prefabricated concealment assembly according to one embodiment of the present invention. 
     
    
    
     The Figures depict embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Exemplary embodiments of systems and methods for concealing RF antennas with RF transparent material, as are illustrated in the accompanying drawings, are hereinafter presented. Consistent with the general principles of the present invention, an antenna concealment assembly  100  is presented that conceals one or more RF antennas with an assembly composed of RF transparent material. 
       FIG. 1  shows a perspective view of a wireless antenna support structure  110  possessing mounting fixtures for a prefabricated concealment assembly according to one embodiment of the present invention. As can be appreciated by one skilled in the relevant art, most building roofs are either flat or gabled. A cellular or wireless antenna support structure  110 , as shown in  FIG. 1 , provides a means by which the support structure can be attached to existing roof support points capable of structurally supporting the antenna and concealment assembly. These structural attach points vary depending on the particular environment, roof, or building on which the antenna support structure  110  is installed. The building&#39;s roof design and the size and weight of the steel antenna frame, with attached concealment members and panels, will dictate if a ballasted or roof mounted product is possible. In most cases, the requirement will be for the frame and concealment assembly to be structurally mounted directly to the building&#39;s roof. In other embodiments, and without departing from the scope of the invention, the antenna support structure can be attached to a supporting structure separate or independent of a building or roof. 
     As shown in  FIG. 1 , the antenna support structure  110  includes both horizontal and vertical members as required to support the antennas begin housed within the structure. In the embodiment depicted in  FIG. 1 , a rectangular structure possessing four attachment points  120  for attaching the antenna support structure  110  to the underlying structural building are evident. According to one embodiment of the present invention, the antenna support structure includes an inner and outer support ring. The inner support ring or structure is associated with the housing and mounting of the antennas. In the embodiment shown in  FIG. 1 , two opposing inner support structures are provided for housing and attaching various antenna. The outer support ring is configured to allow the transmitting side of the antenna to face outward from the inner ring and yet be concealed by the concealment assembly  160  attached to the outer ring. Associated with the outer support ring are upper and lower cross members  145  that house a plurality of mounting platforms  140 . The mounting platforms  140  are, in one embodiment of the present invention, oriented along the horizontal members of the antenna support structure  110  that comprise the outer ring. In other embodiments, the support structure may be of other shapes such as cylindrical or triangular based on the underlying antenna configuration. 
     As shown in  FIG. 1 , mounting platforms  140  are positioned on horizontal cross members  145  of the external antenna support structural  110  ring in a manner to accept vertical support members of the concealment assembly  100  as will be subsequently described. 
     In one embodiment of the present invention, an adjustable square, tubular steel frame  160  comprising four or more structural roof attachment points  120  is prefabricated so as to allow the structure&#39;s  110  steel frame and attachment points  120  be adjusted in advance or in the field for a structural connection. Above those points, the remaining components of the antenna support structure  110  and concealment assembly  100  are interchangeable and independent of the roofs contact points. 
     Once the roof frame measurements have been determined and the antenna support structure  110  roof attachment points  120  are adjusted accordingly, additional vertical connection members  150  and corresponding cross members  145  can be constructed. The mounting platforms  140  can thereafter be attached to the upper and lower cross members  145  as required for each individual configuration. In one embodiment of the present invention, and as shown in  FIG. 2 , the various mounting platforms  145  include both corner mounting platforms and mid-member mounting platforms. The mounting platforms are spaced along the cross members  145  as required to provide adequate structural support for the concealment assembly  100 . 
     The present invention&#39;s pre-engineered and prefabricated concealment assembly is independent of the variable steel roof mount dimensions from individual sites, and therefore can be produced with greater efficiencies with maintenance free, UV protected materials. These materials can be produced in multiple colors as well as optional faux stone or brick digital wallpaper coverings to match existing buildings. The present invention can be shipped to the site as individual wrapped pieces as a knock-down kit with assembly instructions, or it can be fully assembled at the fabrication factory and shipped to the cellular construction site as a completed unit ready to be hoisted and attached to the roof mounts. Because the antenna support structure  110  can be adjustable, the on-center distance between each vertical support  150  is determined by the design and specifications of the antenna concealment assembly  100 , not by a roofs variable connection points. 
       FIG. 2  shows a perspective view of a cellular antenna support structure  110  for a prefabricated concealment assembly  100  showing one orientation of antenna components in comparison to vertical support members  230  of the concealment assembly  100  according to one embodiment of the present invention. As previously mentioned, the antenna support structure  110  possesses an internal ring or structure configured to house the antenna and an external structure configured to house the concealment assembly. While in ideal conditions the antenna support structure  110  would also be composed of RF transparent material, the orientation of each antenna mitigates the impact of any interference caused by the antenna support structure  110  while maximizing the importance of the RF transparency of the concealment assembly  100 . 
       FIG. 2  further depicts, according to one embodiment of the present invention, a plurality of vertical support members  230  fixed to various mounting platforms  140 . Each vertical support member  230  is accepted into a mounting bracket of an upper and lower mounting platform  210 ,  250 . Once received by the mounting platform  210 ,  250 , the vertical support member  230  is fixed to the platform using a RF transparent fastener. The vertical support members  230  are positioned along the antenna support structure  110  as necessary to bear the weight of the concealment assembly  100 . In one embodiment of the present invention, each vertical support member  230  is composed substantially of hollow PVC material with walls of the vertical support member ranging between 0.120 and 0.270 inches in thickness. PVC possesses the inherent qualities of being substantially RF transparent in the 3 kHz to the 300 GHz range while providing adequate structural strength to support the concealment assembly. Furthermore, the well established manufacturing process of PVC products enable components such as the vertical support member  230  be to economically produced. 
     As shown in  FIG. 2  and according to yet another embodiment of the present invention, horizontal support members  260  are attached to the vertical support members  130  to produce several concealment assembly cross members. As with the vertical support members  230 , the horizontal support members  260  are composed of a material that is substantially RF transparent. In one embodiment of the present invention, the horizontal cross members  260  are fashioned out of hollow extruded PVC possessing a wall thickness between 0.080 and 0.095 inches. As will be appreciated by one skilled in the art, other material that is substantially RF transparent and offers adequate rigidity and strength to support a concealment assembly is within the scope of, and is indeed contemplated by, the present invention. The present invention&#39;s RF transparent PVC members and panels have a dielectric constant in the range of 2.0 to 3.0. This dielectric constant is very comparable to the fiberglass products used today in customized antenna concealment structures. However, the fiberglass materials, due to their lower overall rigidity and strength, are generally engineered to be much denser and thicker than the present invention&#39;s PVC members and panels. Therefore the present invention provides a significant decrease in RF loss or attenuation over materials and designs of the prior art. It is also to be understood that although the invention has been described and illustrated with a certain degree of particularity, the present disclosure is made only by way of example, and that numerous changes in the combination, composition, and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention. 
     As is further illustrated in  FIG. 2 , the horizontal support members  260  and vertical support members can be positioned so as to minimize the volume (total thickness) of concealment material (structure) through which the transmission cone  280  must pass. The positioning of the structure is based on projected wind and other structural loads and the inherent strength of the vertical and horizontal support members combined with the rigidity of the concealment panel  290  which complete the concealment. 
     The concealment panels  290  are, in this embodiment of the present invention, prefabricated and interlocking to match the outside dimensions of the antenna support structure  110  with the vertical support members  230  and the horizontal support members  260  in place. Accordingly, once the initial dimensions of the attaching points  120  of the antenna support structure  110  are known, the remaining components of the antenna concealment assembly  100 , and for that matter the antenna support structure  110 , can be prefabricated offsite and mounted on the attachment points  120  quickly and with minimal, if any, customization. 
     Each concealment panel  290  is composed of a material that is substantially RF transparent such as PVC with a thickness of substantially between 0.025 and 0.050 mm. Based on the positioning of the vertical and horizontal support members  230 ,  290 , the concealment panel can be prefabricated to possesses structural channel to enhance rigidity without significantly impacting its RF transparency. In addition, each panel can be fabricated to provide an exterior appearance consistent with the surrounding environment. For example, the exterior surface of the panels  290  can resemble a brick facade or be fashioned to resemble wood siding. Indeed in one embodiment of the present invention, concealment panels are corrugated to aid in flexibility as well as ventilated to mitigate aerodynamic forces imposed on the antenna concealment assembly  100  due to wind forces. In an exemplary embodiment of the present invention, the concealment panels  290  are connected to the horizontal support members  260  using a plurality of RF transparent clasps. The clasps are used to connect the panels  290  using predrilled holes that align with receiving holes in the horizontal support members  260 . In yet another embodiment of the present invention, the clasps used to connect the panels  290  to the horizontal support member  2600  are of a self-locking nature that allow for quick and permanent coupling of each panel  290  to the corresponding horizontal support member  260 . 
       FIG. 3  shows, according to one embodiment of the present invention, a top and side view of an antenna support structure  110  possessing a concealment assembly  100  attached to the structure&#39;s exterior. The top view of the concealment assembly  100  shows the antenna support structure  110  to the interior of the concealment assembly  100 . Vertical support members  230  are attached to the outside of the antenna support structure  100 , so as not to interfere with the positioning and orientation of the antenna  340  mounted on the interior portions of the antenna support structure  110 . In the embodiment shown in  FIG. 3 , two sets of two antenna  340  are positioned spanning between an upper and lower inner cross members  145 . The antenna  340  are respectively oriented outward away from the inner antenna support structure  110  and toward the concealment assembly  100 . The orientation of these antenna  340  serve to illustrate the need to ensure that the concealment assembly  100  is composed of a material that is substantially RF transparent. Furthermore, a centralized antenna  350  is directed toward a wall designed to minimize structural component interference. Connected to the outside of the vertical support members  230  are the horizontal support members  230  and the concealment panels  290 . 
     The side view of the concealment assembly  100 , also shown in  FIG. 3 , shows one embodiment of a configuration of vertical and horizontal support members  230 ,  260  that are used to ultimately house the concealment panels  290 . The fence-like structure is fashioned based on a particular application. Those applications or concealment projects likely to be placed in an environment subject to severe environmental conditions may necessitate a stronger structure. The number and spacing of the vertical and horizontal support members  230 ,  260  can be varied depending on individual applications balanced with the need for RF transparency. 
       FIG. 4  shows a top and side view of one embodiment of components of the concealment assembly  100  in a final assembled configuration. Looking first at the side view, a mounting platform  140  coupled to the antenna support structure  110  houses the top end of a vertical support member  230 . The vertical support member  230  is joined to a horizontal support member  260  via a RF transparent fastener  720 . In one embodiment of the present invention, portions of the vertical support member  230  and/or the horizontal support member  260  are removed to provide access to prefabricated openings used in conjunction with the appropriate fasteners  720 . Attached to the horizontal support members  260  via RF transparent clasps  730 , or other fastening means, are RF transparent panels  290 . Again, the openings used to accept the various clasps  730  and fasteners  720  are prefabricated to facilitate quick and economical on-site construction. Also shown in  FIG. 4 , and according to another embodiment of the present invention, is an overhanging J-channel  740  that affixes to the horizontal support member  260  and allows the RF transparent panel  290  to be inserted and coupled to the horizontal support member without necessitating any type of clasp or fastening device. 
     The top view of a final assembly of components of the concealment assembly  100  provides additional insight as to the construction and design of one embodiment of the present invention. This top view shows a corner of a concealment assembly  100  having a vertical support member  230  joined to two horizontal support members  410  to which two RF transparent panels  290  are attached. Significantly, this depiction shows that in one exemplary embodiment of the present invention, the vertical support members  230  are hollow columns.  FIG. 4  depicts the vertical support member  230  as a square column with a void central region. This type of hollow construction increases rigidity and strength of the member while preserving a low overall material density. Material density is directly related to RF transparency and thus a design using hollow structural members is a significant advantage of the present invention. 
     As shown in  FIG. 4 , two horizontal support members  260 , also possessing a central region void of material, are joined to the vertical support member  230  using RF transparent fasteners  720 . RF transparent panels  290  are thereafter attached to the horizontal support members  260  forming the concealment assembly  100 . The embodiment shown in  FIG. 4  depicts a mitered corner whereby the two horizontal support members  260  are joined. The RF transparent panels  290  coupled to each horizontal support member  260  forming an overlapping corner configuration. In this embodiment, an RF transparent trim or cap such as J-channel  740  is used to frame and capture the panels  290  along the concealment assembly&#39;s edges to provide a finished, maintenance-free appearance. 
     The entire assembly comprising the vertical support members  230 , the horizontal support members  260 , the RF transparent panels  290 , and the RF transparent fasteners provide a structurally sound concealment of RF antenna while minimizing the material density and thus the interference associated by such a concealment assembly. By using components composed substantially of PVC, the overall RF transparency of the concealment assembly  100 , especially high component in regions of the assembly such as corners, is considerably below that of concealment assemblies known in the prior art. 
     As was previously suggested, the assembly and creation of the concealment assembly  100  is efficient and economical. As a detailed illustration of this process, the following step-by-step process is provided to aid the reader in gaining a full understanding of the scope of the present invention. 
     Once the antenna support structure  110  is erected on the site, or, alternatively, the exact dimensions of the antenna support structure are known, the components of the concealment assembly  100  can be fashioned. These components are then delivered to the site for assembly. One should note that in an alternative embodiment of the present invention, the entire concealment assembly  100  can be assembled off site and transported to the final resting place for placement on the roof&#39;s structural supports. In an exemplary embodiment of the present invention, the vertical support members  230 , are arranged and positioned between each of the corresponding mounting platforms  140  and attached securely with self tapping screws. Once the vertical support member  230  skeleton is erected between top and bottom mounting platforms  230 , pre-cut and routed horizontal support members  260  are attached. The horizontal support members  260  are individually spaced down and across the vertical support members  230  (based on the pre-engineered on-center requirements) from the top of assembly  100  to the bottom of the assembly  100 ), depending on the structural characteristics of the horizontal support member  260  as combined with the concealment panel  290 . 
     Pre-drilled holes in the vertical support members  230  match up exactly with pre-drilled holes in the horizontal support members  260 . As mentioned above, access holes drilled into the non-touching walls allow the RF transparent bolts and nuts to be tightened down, connecting the vertical support members  230  securely to the horizontal support members  260 . These access holes are later hidden by the RF transparent panels  290 . 
     After attaching each row of horizontal support members  260  to corresponding vertical support members  230 , the completed concealment assembly  100  skeleton is now ready to accept RF transparent panels  290 . RF transparent accessory trim is then used to frame the unit along the outer facing edges of the horizontal support members  260  and RF panel  290  junctures. 
     In one embodiment of the present invention, unique RF transparent nylon push pins  730  having a barbed edge are inserted into the panel  290  horizontal support member  260  combination to secure each panel  290  to corresponding horizontal support member  260 . The push pins  730  secure the RF transparent panel  290  to the horizontal support members  260 , and provide the concealment assembly  100  with additional engineered strength to meet rooftop wind loads. 
     The push pins  730  snap open inside the hollow horizontal support member  260  securely and structurally fastening the panel  290 . This building process moves along horizontally as panels are inserted and connected to the previous panel, then vertically along each horizontal support member  260  until the concealment assembly unit  100  is completed. 
     Depending on the required concealment plan, an additional layer of the outdoor faux stone or brick digital vinyl wallpaper may be applied to the external sheathing in order to match the exact brick or stone pattern used on the original building. 
     In yet another embodiment of the present invention, a removable door panel (if applicable) is installed to permit access to the antenna and internal structure. In another embodiment of the present invention, the entire completed concealment assembly  100  can be shipped as a completed antenna concealment unit with steel frame, PVC skeleton, and panels attached. 
     While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made without departing from the spirit and scope of the invention. It should be understood that this description has been made by way of example, and that the invention is defined by the scope of the following claims.

Technology Category: h