The present invention relates generally to antennas and more particularly to an antenna tower and a support structure for mounting a wireless communications antenna on such a tower.
Modern wireless communications systems, such as cellular or personal communication subscriber (PCS) telephone systems, are in wide use around the world. These systems generally include one or more antennas that are mounted on an associated antenna tower. Each antenna tower typically is associated with a base station.
In order to provide wireless service to a given area (service area), wireless service providers normally erect one or more antenna towers at predetermined locations within the service area. As wireless communications services have become more popular, service providers have endeavored to build out wireless communications systems to provide service to larger areas. As a result, it has become common in many communities for there to be several antenna towers dotting the landscape.
Antennas and antenna towers are subjected to demanding environmental factors, such as high winds. Typical antenna towers have been designed and constructed to provide the strength necessary to support an antenna subjected to these environmental conditions. This has meant that the typical antenna mast/tower is large, bulky and generally unappealing in appearance. Often, these antenna towers are obtrusive and contrast sharply with the surrounding environment in a negative way, and are commonly viewed by the community as “eye-sores.” This is due in part to the fact that most typical antenna towers have been constructed to provide functionality at the expense of form or aesthetics.
To address this aesthetics issue, efforts have been made in recent years to provide antenna towers, including associated support structures, which are less obtrusive to the eye and more compact in profile/structure. Unfortunately, the needs for high strength have tended to make it difficult to provide a compact structure.
As wireless communication becomes more and more ubiquitous, there is an ever-increasing demand for more antenna towers and for more equipment mounted on a single tower. This demand for greater equipment mounting on a single antenna leads to antenna towers that are bulkier, not more compact, thereby creating a tension between the need for greater capacity and the desire to make the antenna tower more compact (and therefore less obtrusive). The growing demand for greater equipment mounting on individual antenna towers also leads to a need for increased structural strength, due to the greater mass and length of the antenna complex mounted at the top of the tower. This need for increased strength also tends to lead to larger structures, as mentioned above. One approach to this dilemma has been to make the tower and associated equipment as large as desired and then to try to obscure the structure to the greatest extent possible with camouflage techniques to try to blend the tower into the surrounding environment.
Examples of known antenna systems designed to blend into the surrounding area include that shown in U.S. Pat. No. 6,122,866 to Trevor et al., for a Method and Apparatus for Concealment and Disguisement of Antenna Structures, which discloses a support structure (
Other known antenna support systems that take on a somewhat compact profile are shown in U.S. Pat. No. 5,641,141 to Goodwin, for an Antenna Mounting System. In Goodwin, an antenna mounting apparatus is shown which includes three antenna members. The antenna members are positioned so as to provide adequate communications within a selected radial distance. Another antenna system having a somewhat compact profile is shown in U.S. Pat. No. 5,880,701 to Bhame et. al., for an Enclosed Wireless Telecommunications Antenna. Bhame shows an antenna module that is configured to support three dual polarization antenna panels.
At least as early as January 2001, EMS Wireless (a division of EMS Technologies, Inc.), the assignee of the present application, was offering for sale and selling a low-strength antenna support module, which could be mounted atop a mast. The low-strength unit was designed to be used singly or to allow at most two such modules to be stacked together. The module included a lower plate, an upper plate and a central post extending between the plates. The module was shown and described in the January 2001 EMS Wireless Product Catalog. The present inventors, however, have found the low-strength module to be less than ideal in high wind applications or other high strength applications.
Unfortunately, known antenna tower designs generally do not provide the strength to support more than a limited number of antenna panels or external attachments, such as flags, banners, signage and the like, combined with an aesthetically pleasing compact appearance. Further, they generally do not provide the strength needed to withstand harsh environmental stresses, in particular high wind, that are often encountered. This can be particularly important in certain regions, such as coastal areas.
In view of the above deficiencies of the prior art, there is yet a need for a compact antenna tower and support structure that is capable of accommodating more than a limited number of antennas or antenna panels. Further, there is a need for a compact antenna tower/support structure that is capable of supporting external attachments, such as flags, banners, signage and the like. Further, there is a need for such compact antenna tower/support structures to be capable of withstanding high winds. It is to the provision of such an antenna tower and support structure therefor that the present invention is primarily directed.
Briefly described, the present invention is an antenna tower and a support structure for use with an antenna tower, which allow a number of antennas or antenna panels to be mounted thereto, while maintaining the compactness of the overall structure and still providing high strength, such as is needed to resist high winds. In one preferred aspect, the invention preferably comprises an antenna tower including a mast. The antenna tower according to this preferred aspect of the invention also includes an antenna support structure mounted to the antenna mast for supporting one or more antennas or antenna panels. The antenna support structure includes a bottom element for mounting to the mast (or to another antenna support structure) and a top element spaced from the bottom element. A beam with multiple webs extends between the bottom element and the top element. The beam includes a central post and a number of stiffening webs extending generally radially outwardly from the central post. The stiffening webs help to provide substantially greater stiffness against flexure and bending, without making the overall structure larger (or not much larger effectively) or heavier. In this way, an antenna tower can be constructed that meets the competing needs of great structural rigidity, compactness, and light weight.
In another aspect, the invention comprises an antenna tower that includes a mast and at least three antenna support modules mounted atop the mast. Each of the antenna support modules includes a top plate, a bottom plate, and a high-strength beam extending therebetween. The high-strength beam provides the bending strength needed to allow three or more such modules to be stacked atop the mast. Preferably, the high-strength beam includes a central post and a plurality of reinforcing gussets or other stiffening structures extending radially outwardly from the central post.
In another preferred aspect, the invention comprises an antenna support module for mounting to an antenna mast. The support module according to this aspect of the invention preferably includes a bottom plate for mounting to the mast or to another module, and a top plate spaced from the bottom plate. A beam extends between the bottom plate and the top plate. The beam includes multiple vanes that extend outwardly from a central post. Preferably, each of the vanes terminates in a distal flange which extends across the end of the vane.
The configuration, quantity, orientation, and other particulars of the webs or vanes according to these first two aspects of the invention can be varied widely according to the present invention. As will be explained in more detail below, three such webs or vanes can be employed, or four or more. Indeed, even as few as two such vanes or webs could be employed in some situations. Moreover, the webs or vanes could be evenly spaced or unevenly spaced from one another. The webs or vanes could be perforated or solid. The webs or vanes can be of different sizes, shapes, or construction. Furthermore, the webs or vanes can be used with or without flanges, although it is preferred that flanges be formed or attached to the ends of the webs or vanes to provide even more stiffness against bending. Other features and advantages of the present invention will become apparent to those skilled in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages are included herein within the scope of the present invention.
The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
The present invention provides a compact antenna tower and support structure for use with an antenna tower that are capable of supporting multiple antenna panels. Towers and support structures according to the present invention are also capable of withstanding high winds. Moreover, because of the very good stiffness and strength obtained, the present invention allows the use of multiple support modules stacked on top of one or above another atop a tower mast, while still providing good resistance against excessive flexure from wind. Other modular structures, such as a support module for tower-mounted electronics, can be stacked between antenna support modules. It should be understood that the invention is not to be limited to the mounting of antennas or antenna panels, but instead could be used to mount a wide variety of components on a communications tower. The invention also allows the mounting of items not directly associated with wireless communications, such as a large flag on the top thereof (or other structures) that tend to create large bending loads, due to the enhanced structural rigidity afforded by the beam design of the present invention.
Referring the reader now to
In addition to the bottom plate or lower mounting plate 112, the support structure 100 also includes a top plate or ceiling or cap 110. The top plate 110 and the bottom plate 112 are designed to work together, to allow a support structure 100 to be mounted atop a tower mast directly or to be mounted atop another support structure 100. A center member or central post 120 is provided and extends between the top plate 110 and the bottom plate 112. The central post is rigidly secured to the upper plate and the lower plate, as by welding or some other known technique. The central post preferably is perpendicular to the upper and lower plates. As shown, one or more wings 130 are rigidly mounted to the central post along some or all of its length, as for example by welding, and extend radially outwardly. They also are welded, at least in some places, to the top plate 110 and to the bottom plate 112. These wings function to stiffen the structure against bending loads (they also provide some additional axial compression strength). Together, the central post and the outwardly extending wings are sometimes referred to herein as a “beam.” Although “beams” are more often thought of as horizontal members (and less commonly vertical) and here the beam is vertical, this structure according to the present invention can be described as a “beam” inasmuch as it bears bending loads across its axial length instead of only compression loads along its length.
The wings 130 each preferably include a web portion 131 and a flange portion 132. Both the web portions 131 and the flange portions 132 extend from the lower mounting plate 112 to the upper plate 110. The webs or vanes or stiffening gussets 131 extend outwardly from the central post 120. It is preferred that the webs extend radially outwardly from the central post. Moreover, while it is preferred that the webs terminate in the flanges 132, it should be recognized that in some circumstances the flanges 132 could be dispensed with. For example, if a flange would interfere with or adversely affect an antenna's beam, it might be helpful to eliminate the flange. In that instance, the strength could be maintained at a similarly high level by thickening or widening the web (it would also be helpful to secure the web at the top and bottom to the top and bottom plates). In other circumstances, it might even be possible to omit the webs and to secure the flanges to the upper and lower plates. In all of these variations, the manner of making the panel support structure stronger against bending forces takes advantage of beam design principles in which as the structure is placed under bending stresses, one part of the structure is placed in tension, while another part is placed in compression. Moreover, by spacing these tension and compression elements apart, greater resistance to bending is achieved. These principles are at work in the present invention.
The wings 130 each preferably include perforated or discontinuous webs 131, as shown in these figures. Alternatively, the webs could be made solid, which adds some weight and some strength. But the discontinuous webs have been found to provide adequate additional strength over known prior art designs and do so while minimizing weight and providing good structural opportunities for mounting antenna panels and other items to the support structure 100. The webs depicted show a uniform pattern of openings, but it should be understood that the invention is not to be limited to a fixed and repeating pattern of openings.
In this embodiment the top and bottom plates 110 and 112 preferably are circular in shape. Further, the central post 120 preferably is aligned with the center points, respectively, of both top plate 110 and bottom plate 112. It will be recognized that the plates 110 and 112 may be configured to have a shape other than a generally circular shape, including, but not limited to, a square, rectangular or triangular shape. In particular, the plates 110 and 112 could be configured to have a shape to complement the pattern of the wings, such as a generally triangular shape to match three wings. Also, these mounting plates carry holes formed therein (see
Referring now to
It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, and merely serve to set forth a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of the present invention and protected by the following claims.
Number | Name | Date | Kind |
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3681770 | Alford | Aug 1972 | A |
5966102 | Runyon | Oct 1999 | A |
6222503 | Gietema et al. | Apr 2001 | B1 |
Number | Date | Country | |
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20050007295 A1 | Jan 2005 | US |