Abstract:
A low cost antenna horn for outdoor use having an extended housing with a unibody construction to enclose a waveguide and polarizing septum, the assembly of which rigidly retains and orients the waveguide and polarizing septum without using traditional hardware or sealants.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to currently pending U.S. patent application No. 61/791,232 filed Mar. 15, 2013 entitled Antenna Horn with Unibody Construction, the contents of which are incorporated herein by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to antennas, and more particularly to horn antennas with a circularly polarized feed having a singular external housing. 
       BACKGROUND 
       [0003]    Communication systems that use circularly polarized signals require antennas with circular reflector profiles that decouple the two vector components that are separated by 90 degrees. Circularly polarized antennas maintain signal integrity by maintaining substantially the same signal magnitude at substantially the same orthogonal relationship. Circularly polarized antennas are useful for two-way satellite communications in which signals are transmitted in circular polarity. 
         [0004]    Feed horns, those known in the art, are generally multi-piece construction in order to manufacture the individual components such as the horn, the polarizer housing, the waveguide, and the polarizer. Many drawbacks exist in multi-piece feed horns, particularly those for use in outdoor applications, including expensive gaskets and complicated assembly. Normally, the polarizer housing contains the waveguide and polarizer, which is then coupled to the horn and transceiver. These components are assembled with great care to ensure high performance with no moisture ingress. Even small gaps between components can contribute to large efficiency loss in signals, and provide an entry point for moisture that can then damage transceiver electronics. Complex, custom tooling and fixtures are used in order ensure alignment of the components and to facilitate manufacture. Thus, there is a need for a low cost, high volume, high performance, and highly reliable feed horn for outdoor applications. 
       SUMMARY 
       [0005]    The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview, and is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. 
         [0006]    In one aspect of various embodiments, an apparatus for satellite communication is provided, the apparatus comprising: a feed horn having a mouth aperture at a first end, a waveguide interconnect at a second end, and an integrated polarizer assembly housing between the first end and second end, the integrated polarizer assembly housing having an interior surface disposed about a central axis defining a longitudinal interior region; and a polarizer assembly in contact with at least a portion of the interior surface and contained substantially within the longitudinal interior region, the polarizer assembly comprising a waveguide channel and a polarizing septum positioned within the waveguide channel. 
         [0007]    In another aspect of various embodiments, an apparatus for satellite communication is provided, the apparatus comprising: a unibody feed horn means having a polarizer assembly housing with a central longitudinal axis; means for guiding a signal; means for polarizing the signal; means for nesting the signal polarizing means within the signal guiding means, wherein the nesting means comprises a polarizer assembly; engaging means for engaging the polarizer assembly into the unibody feed horn means; and orienting means for orienting the polarizer assembly within the unibody feed horn means. 
         [0008]    In still another aspect of various embodiments, a method for manufacturing a satellite communication apparatus is provided, the method comprising: a method of manufacturing an apparatus, the method comprising: forming a polarizer assembly having a waveguide and a polarizing septum; obtaining a feed horn having an extended housing disposed about a central longitudinal axis, wherein the extended housing of the feed horn includes an interior cavity; and inserting the polarizer assembly into the extended housing of the feed horn. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is a perspective view of an embodiment antenna horn with unibody construction. 
           [0010]      FIG. 2  is a rear, exploded perspective view of  FIG. 1 . 
           [0011]      FIG. 3  is a rear end view of an embodiment antenna horn. 
           [0012]      FIG. 4  is a perspective section view of  FIG. 1 . 
           [0013]      FIG. 5  is a side section view of  FIG. 1 . 
           [0014]      FIG. 6  is a perspective section view of another embodiment antenna horn. 
           [0015]      FIG. 7  is a perspective view of an embodiment polarizer assembly. 
           [0016]      FIG. 8  is an exploded perspective view of  FIG. 7 . 
           [0017]      FIG. 9  is a perspective section view of still another embodiment antenna horn. 
           [0018]      FIG. 10  is a perspective view of another embodiment polarizer assembly. 
           [0019]      FIG. 11  is an exploded perspective view of  FIG. 10 . 
           [0020]      FIG. 12  is a perspective section view of yet another embodiment antenna horn. 
           [0021]      FIG. 13  is a perspective view of still another embodiment polarizer assembly. 
           [0022]      FIG. 14  is an exploded perspective view of  FIG. 13 . 
           [0023]      FIG. 15  is a flow chart of an embodiment manufacturing method. 
           [0024]      FIG. 16  is a perspective section view of yet another embodiment antenna horn. 
           [0025]      FIG. 17  is a perspective view of still another embodiment polarizer assembly. 
           [0026]      FIG. 18  is an exploded perspective view of  FIG. 17 . 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    In the following detailed descriptions of various embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown, by way of illustration, specific embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure. 
         [0028]      FIG. 1  is a perspective view of an embodiment antenna horn  100  with a unibody construction. The unibody may be constructed through one of several suitable processes such as machining, casting, forging, sintering, layered printing, or the like. External and internal geometries may be optimized through various constructions to minimize overall weight and cost, maximize strength and rigidity, both, or neither. The horn  101 , otherwise known as a first end, may comprise a mouth aperture  104 . A waveguide interconnect  103 , otherwise known as a second end  201 , may comprise a flange with bolt pattern  106 , an assembly orientation notch  105 , and a polarization orientation tab  107 . The horn  101  has an integrated polarizer assembly housing  102  that may uninterruptedly link the horn  101  to the waveguide interconnect  103 , and the internal components (see  FIG. 2 ) may be housed within the integrated polarizer assembly housing  102 . 
         [0029]    In an embodiment, the integrated polarizer assembly housing  102 , alternatively referred to as a horn with extended housing  602 , 902 , 1202  disposed about a central longitudinal axis  401 , may be a single component formed by any of the several processes previously mentioned. The singular body, or unibody, eliminates joints and the need for gaskets, eliminates the need for bolts or other connecting means to join the horn  101 , waveguide housing (not shown), and waveguide interconnect  103 , and simplifies manufacture by eliminating complex alignment fixtures. 
         [0030]    The internal components can be seen more clearly in  FIG. 2 , an exploded perspective view of  FIG. 1 , as a first waveguide half  204  and a second waveguide half  205 . In an embodiment, the waveguide halves  204 , 205  may be substantially identical in order to minimize part variation, increase amount of product produced per unit time, and reduce cost. The waveguide halves  204 , 205  may have a plurality of mating surfaces  305 , 306  adjacent to the polarizing septum alignment ridges  206 , 207  that may engage during assembly and/or after insertion into the integrated polarizer assembly housing  102 . A first waveguide half  204  comprises a first mating surface  305  and the second waveguide half  205  comprises a second mating surface  306 . The waveguide halves  204 , 205  may comprise polarizing septum alignment ridges  206 , 207  formed to a depth that is at least less than the thickness of a polarizing septum  203 . The waveguide halves  204 , 205  may sandwich the polarizing septum  203  therebetween prior to insertion into the integrated polarizer assembly housing  102 . 
         [0031]    In an embodiment, the waveguide halves  204 , 205  may be formed as a single component with polarizing septum alignment ridges  206 , 207  longitudinally formed into the interior surface  403 . The polarizing septum  203  may be press-fit into a singular waveguide (not shown) with an axial force from the end comprising the waveguide interconnect  103 . In this manner, the polarizing septum is nested within the singular waveguide. Additional nesting means are contemplated such as welding, molding the waveguide (not shown) around the polarizing septum  203 , casting the polarizer assembly  210  as a whole, machining, or the like. 
         [0032]    The polarizing septum  203 , including additional means for polarizing a signal, converts between both sense of circular polarization and linear depending on the direction of the propagating signal; i.e. transmit or receive. In an embodiment, the polarizing septum  203  may be stepped, tapered, or other suitable configurations. 
         [0033]    In an embodiment, the waveguide halves  204 , 205  may also comprise at least one protruding boss  209  adapted to engage a corresponding notch  208  in the polarizing septum  203  in order to longitudinally position the polarizing septum  203  within the polarizer assembly  210 . The integrated polarizer assembly housing  102  has an interior surface  202 , which may also be defined as the longitudinal interior region. The interior surface  202  may be conical and may at least partially engage the exterior surface of the waveguide halves  204 , 205 , which may be tapered at substantially the same angle as the conical interior surface  202 . In an embodiment, the outer surface is interspersed with longitudinal fins  304  of the waveguide half  204  and may engage the interior surface  202  after at least partial insertion into the integrated polarizer assembly housing  102 . 
         [0034]    A rear end view of an embodiment of an antenna horn  100  is illustrated in  FIG. 3 . Fins  304  of the waveguide halves  204 , 205  engage the antenna horn  100  at various interface points  301  along the circumference of the interior surface  202 . In an embodiment, the waveguide halves  204 , 205  and polarizing septum  203  may loosely join to form the polarizer assembly  210  and the polarizer assembly  210  may slide into the integrated polarizer assembly housing  102  from the second end  201  to press-fit against the interior surface  202 . A force applied by the press-fit engagement may act in a direction substantially perpendicular to and radially inward from the interior surface  202 , and is transferred through the fins  304  toward the polarizing septum  203 . In this manner, the force substantially rigidly clamps the polarizing septum  203  between the waveguide halves  204 , 205  to maximize signal transmission efficiency. Optimum signal transmission performance may be achieved when the force causes the polarizing septum  203  to be substantially uniformly loaded along the polarizing septum alignment ridges  307 , 308 , shown in  FIG. 3  from the second end  201 . These ridges  307 , 308  run substantially parallel to the longitudinal axis  401 , in a direction of the propagating signal, e.g., the first end  101  toward the second end  201 . 
         [0035]    Whereas in the aforementioned embodiment with substantially uniform loading along the polarizing septum  203 , conversely, force may not be applied at locations  303  because none of the various interface points  301  intersect the interior surface  202  at locations  303 . It is contemplated that a different arrangement of fins  304  and/or a different number of fins  304  may accomplish substantially the same radial load. For example, the fins  304  may radiate outward from the central longitudinal axis  401  rather than only perpendicular to the mating surfaces  305 , 306 . 
         [0036]    The orientation of the polarizing septum  203  relative to the waveguide interconnect  103  affects the performance of the antenna  100 , 200 . In an embodiment, at least one keying feature  302  provides a means to orient the polarizer assembly  210  upon insertion into the integrated polarizer assembly housing  102 . A key  302  may be adapted for insertion into the waveguide interconnect  103 . The keying feature  302  may be a traditional key and keyway, a custom key and key slot, round pin and bore, spline, or other suitable forms. 
         [0037]    Turning now to  FIG. 4  and  FIG. 5 , an illustration is provided to shown a perspective section view of  FIG. 1  and a side section view of  FIG. 1 . In  FIG. 4 , a central longitudinal axis  401  is shown with the antenna horn  100  disposed about the axis  401 . The waveguide channel  403 , of the waveguide  204 , 205  is substantially orthogonally disposed about the axis. The internal waveguide channel  403  guides the signal to and from the transceiver (not shown). Means for guiding the signal may be altered to change signal transmission performance. Examples of altered signal guiding means may include interior corners of the waveguide channel  403  having radii, a tapered interior surface  201 , and a textured interior surface  201 . 
         [0038]    In an embodiment, a ledge  402  formed in the integrated polarizer assembly housing  102  may provide a limit for insertion depth of the polarizer assembly  210 . As illustrated in  FIG. 5 , the interior surface  202  of the integrated polarizer assembly housing  102  may be tapered to engage the polarizer assembly  210  at a longitudinal location  501 . This longitudinal location  501  may vary to adjust the amount of radial clamping force or may vary due to manufacturing tolerances. Once engaged, continuing to apply force to the polarizer assembly  210  in a direction substantially parallel to the central longitudinal axis  401  may begin deforming material in at least one of the waveguide halves  204 , 205 , the integrated polarizer assembly housing  102 , or both. An interior region  502  defined by a tube in the shape of a cylinder, toroid, rectangle, square or other hollowly shaped tube, may provide a reservoir for material buildup that may be ablated from the integrated polarizer assembly housing  102 , waveguide halves  204 , 205 , or both, by the insertion of the polarizer assembly  210 . In this manner, the reservoir may allow the polarizer assembly to fully seat upon the ledge  402  because ablated material does not interfere with insertion depth. 
         [0039]      FIG. 6  is a perspective section view of another embodiment antenna horn  600 . Another embodiment polarizer assembly  601  is shown fully engaged with the extended housing  602 . In an embodiment, the engagement means may be a press fit, clamped fit, threaded joint, or other suitable means. 
         [0040]      FIG. 7  and  FIG. 8  are perspective views of another embodiment polarizer assembly  601 , where  FIG. 8  is an exploded perspective view of  FIG. 7 . In an embodiment, polarizer assembly  601  may have a tube  701  inserted over the outer surface and may be crimped at locations  702 . Application of crimping force may be performed by a tool. The crimping action of the tube  701  may secure together the first waveguide half  801 , the second waveguide half  802 , and the septum polarizer  803  therebetween by applying a radial force on the polarizer assembly  601 . Polarizing septum alignment ridges  804  of the waveguide halves  801 , 802  may support longitudinal edges  805  of the septum polarizer  807 . In this way, the extended housing  602  may not compress the polarizer assembly  601  upon insertion as in other previously disclosed embodiments (see  FIG. 2 ). However, the polarizer assembly  601  may be clamped by an axial force between a second end  603 , alternatively referred to as a waveguide interconnect  603 , of the extended housing  602  and a transceiver housing (not shown). The clamping axial force may at least partially be generated from the polarizer assembly  601  extending beyond an end surface of the waveguide interconnect  603 . In this way, the polarizer assembly  601  may contact the transceiver housing (not shown) before the waveguide interconnect  603  engages the transceiver housing (not shown). 
         [0041]    In an embodiment, the waveguide interconnect  603  may be joined to the transceiver housing (not shown) using screws (not shown) placed through holes  605 . When tightened, screws (not shown) may apply axial force to the waveguide interconnect  603  to engage the antenna horn  600  with the transceiver housing (not shown). Additional attachment means to bring the antenna horn  600  in rigid mating contact with the transceiver housing (not shown) are contemplated including a clamping mechanism, a press-fit, threaded coupling, a pipe thread and knuckle, threaded studs and nuts, or other suitable forms. 
         [0042]    In an embodiment, the waveguide halves  801 , 802  may also comprise at least one protruding boss  806  adapted to engage at least one corresponding notch  807  in the polarizing septum  803  in order to longitudinally position the polarizing septum  803  within the polarizer assembly  601 . In an embodiment, the waveguide halves  801 , 802  may be substantially identical in order to minimize part variation, increase volume, and reduce cost. 
         [0043]      FIG. 9  is a perspective section view of still another embodiment antenna horn  900 . Still another embodiment polarizer assembly  901  is shown fully engaged with the extended housing  902 . In an embodiment, the engagement means may be a press fit, clamped fit, threaded joint, or other suitable means. 
         [0044]      FIG. 10  and  FIG. 11  are perspective views of still another embodiment polarizer assembly  901 , where  FIG. 11  is an exploded perspective view of  FIG. 10 . In an embodiment, polarizer assembly  901  may have a spring clamp  1002  inserted over the outer surface. The insertion means may be a threading action, applying a torsional load to increase the inside diameter of the spring clamp  1002 , both, or neither. Once installed, the spring clamp  1002  secures together the first waveguide half  1101 , the second waveguide half  1102 , and the septum polarizer  1103  therebetween via radial compression. Additional compression means may be employed such as a clamp ring, screws, bolts, a weld, a radial load imparted by the interior surface  202  (as in the antenna horn  100 ), or the like. 
         [0045]      FIG. 12  is a perspective section view of yet another embodiment antenna horn  1200 . Another embodiment polarizer assembly  1201  is shown fully engaged with the extended housing  1202 . In an embodiment, the engagement means may be a press-fit in which a plurality of substantially concentric cylinders on an exterior surface of the polarizer assembly  1201  engage a plurality of substantially concentric cylindrical bores within the interior surface of the extended housing  1202 . It is contemplated that the plurality of cylinders and corresponding cylindrical bores may be tapered to minimize longitudinal length of engagement. 
         [0046]      FIG. 13  and  FIG. 14  are perspective views of yet another embodiment polarizer assembly  1201 , where  FIG. 14  is an exploded perspective view of  FIG. 13 . In an embodiment, the waveguide halves  1401 , 1402  and polarizing septum  1403  may loosely join to form the polarizer assembly  1201  and the polarizer assembly  1201  may slide into the extended housing  1202 . A force applied by the press-fit engagement may act in a direction substantially perpendicular and radially inward and may be transferred to the polarizing septum  1403  along its longitudinal edges. In this manner, the force substantially rigidly clamps the polarizing septum  1403  between the waveguide halves  1401 , 1402  to maximize signal transmission efficiency. 
         [0047]      FIG. 15  is a flow chart for manufacturing an antenna horn. In an embodiment, the process  1500  may begin with forming at least one waveguide according to any of the previously disclosed embodiments (step  1501 ). The polarizing septum may then be formed (step  1502 ) and then the feed horn with extended housing disposed about a central longitudinal axis may be formed (step  1503 ). Steps  1501  through  1503  may be performed in any sequential order. 
         [0048]    In an embodiment, the waveguide and polarizing septum are assembled to form a polarizer assembly (step  1504 ). After  1504 , the process is dependent upon the method in which the polarizer assembly is coupled (step  1505 ). For example, if the polarizer assembly is compressed during and/or after insertion into the interior cavity of the feed horn, then the polarizer assembly may be engaged into the feed horn (step  1506 ). Alternatively, if the polarizer assembly is compressed before insertion into the feed horn, the compressing means may be employed (step  1507 ). As previously disclosed, a group consisting of a spring clamp, a clamp ring, screws, bolts, a weld, a radial load imparted by a surface of the interior cavity may be the compression means. Next, the polarizer assembly may be engaged into the feed horn (step  1506 ) to create the product (step  1508 ). As previously disclosed, engaging means may be a press-fit, clamped fit, threaded joint, or other suitable means. 
         [0049]      FIG. 16  is a perspective section view of a horn assembly  1600  comprising further embodiments of an antenna horn  1602  and a polarizer assembly  1601 . The polarizer assembly  1601  is shown fully engaged with the extended housing  1602 . In an embodiment, the engagement means may be a press fit, clamped fit, threaded joint, or other suitable means. 
         [0050]      FIG. 17  and  FIG. 18  are perspective views of still another embodiment polarizer assembly  1601 , where  FIG. 18  is an exploded perspective view of  FIG. 17 . In this embodiment, the waveguide halves  1801 , 1802  and polarizing septum  1803  may loosely join to form the polarizer assembly  1801 . One or more deformable tangs  1804  may engage corresponding slots  1805  upon assembling the waveguide halves  1801 , 1802 . The polarizing septum  1803  may be more fully seated with the polarizer assembly  1801  through the use of a manufacturing fixture, hydraulic press, or other suitable means, in order to improve transmission efficiency. Permanent deformation may occur to spread the tang  1804  within the corresponding slot  1805  and temporarily join the waveguides halves  1801 , 1802  before sliding the polarizer assembly  1601  into the extended housing  1602 . Upon insertion of the polarizer assembly  1601  into the housing  1602 , a force applied by the press-fit engagement may act in a direction substantially perpendicular and radially inward and may be transferred to the polarizing septum  1603  along its longitudinal edges. In this manner, the force may further clamp the polarizing septum  1603  between the waveguide halves  1801 , 1802  to maximize signal transmission efficiency. The arrangement provides for a uniform distribution of a clamping force so as to prevent deformation of the waveguide that could otherwise impose signal distortion. 
         [0051]    What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.