WO2015076887A1

WO2015076887A1 - Feed assembly interconnection

Info

Publication number: WO2015076887A1
Application number: PCT/US2014/052592
Authority: WO
Inventors: Alastair D. WRIGHT
Original assignee: Commscope Technologies Llc
Priority date: 2013-11-19
Filing date: 2014-08-26
Publication date: 2015-05-28

Abstract

In one embodiment, a base retainer secures a feed assembly to a hub for an antenna reflector. The base retainer has (i) a central element having a retainer hole configured to receive a base of the feed assembly, where the retainer hole has one or more key features that engage one or more corresponding key features of the base of the feed assembly to prevent axial rotation of the feed assembly with respect to the base retainer and (ii) two wing elements, each extending radially from the central element and having structure for securing the base retainer to the hub. The base retainer functions as a tool for rotating the feed assembly with respect to the hub and as a bracket for subsequently securing the feed assembly to the hub.

Description

FEED ASSEMBLY INTERCONNECTION

Cross-Reference to Related Applications

[0001] This application claims the benefit of the filing dates of U.S. provisional application nos. 61/905,942, filed on 1 1/19/13, and 62/013,059, filed on 6/17/14, the teachings of which are incorporated herein by reference in their entirety.

BACKGROUND

Field of the Invention

[0002] The present invention relates to antennas and, more specifically but not exclusively, to feed assemblies for reflector antennas.

Description of the Related Art

[0003] This section introduces aspects that may help facilitate a better understanding of the invention. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is prior art or what is not prior art.

[0004] Reflector antennas may utilize a feed assembly wherein a sub-reflector is supported proximate the focal point of the reflector dish by a dielectric cone at a distal end of a waveguide support. The feed assembly may be coupled to a hub of the reflector antenna by adhesives, fasteners, or the like. The interconnection between the feed assembly and the hub may be a source of RF leakage that may create undesirable backlobes in the reflector antenna signal pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Other embodiments of the invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which like reference numerals identify similar or identical elements.

[0006] FIG. 1 is a schematic isometric exploded view of a feed assembly, a base retainer, and a fastener.

[0007] FIG. 2 is a schematic isometric back view of a portion of an exemplary antenna hub for a reflector dish. [ 0008 ] FIG. 3 is a schematic isometric view of the antenna hub of FIG. 2, with the feed assembly of FIG. 1 seated therewithin.

[ 0009] FIG. 4 is a schematic isometric view of the antenna hub and feed assembly of FIG. 3, with the base retainer of FIG. 1 initially seated upon the base of the feed assembly.

[ 0010 ] FIG. 5 is a schematic isometric view of FIG. 4, with the base retainer and base rotated and fasteners applied.

[ 0011 ] FIG. 6 is a schematic isometric view of a base retainer securing the base of a feed assembly to the antenna hub of FIG. 2 according to an alternative embodiment.

[ 0012 ] FIG. 7 is a schematic exploded isometric view of the base retainer and the hub of FIG. 6 with the base of the feed assembly configured to the hub.

[ 0013 ] FIG. 8 is a schematic isometric view of the base of the feed assembly of FIGs. 6 and 7.

[ 0014 ] FIG. 9 is a schematic isometric view of the base retainer of FIGs. 6 and 7.

DETAILED DESCRIPTION

[ 0015 ] Conventional feed-assembly-to-hub interconnections may represent a significant amount of the overall reflector-antenna-assembly requirements. Further, if the feed-assembly-to-hub interconnection is made without closely following the specific manufacturing steps provided, then electrical-performance-damaging RF leakage may occur. For example, the RF seals/sealant may become twisted, misaligned, and/or crushed due to excessive and/or uneven fastening torque applied to the fasteners used to secure the feed assembly to the hub.

[ 0016] In the exemplary embodiment of FIG. 1 , a feed assembly 1 has a sub-reflector 3 supported by a dielectric cone 5 attached to the distal end of a waveguide 7. The waveguide 7 is coupled at the proximal end to a base 9 dimensioned to seat within a feed hole 1 1 of the hub 13, best shown in FIG. 2.

[ 0017 ] The base 9 includes a key feature 15, such as a plurality of tabs 17 extending radially outward, which mate with corresponding slots 19 of the feed hole 1 1 for passage therethrough, as shown for example in FIGs. 2 and 3. The keying between the tabs 17 and slots 19 prevents rotation of the base 9 with respect to the feed hole 1 1 until the tabs 17 insert far enough to clear ramps 20 provided in the feed hole 1 1 sidewalls.

[0018] A base retainer 23 has a retainer hole 25 with a tool sidewall 38 adapted to key with the tabs 17 of the base 9 for ease of rotation of the base 9 within the feed hole 1 1 . The tool sidewall 38 enables rotation of the base 9 with respect to the hub 13, as represented in FIGs. 4 and 5.

[0019] Upon rotation of the base 9, the ramps 20 (FIG. 2) engage engagement surfaces 33 (FIGs. 1 and 3) of the tabs 17, drawing the base 9 against the distal side of the hub 13 until a seat shoulder 21 (FIG. 1 ) of the base 9 seats against the hub 13. The tool sidewall 38 enables rotation of the base 9, without an additional tool.

[0020] A thickness of the hub 13 between the thickest portion of the ramps 20 and the distal side of the hub 13 is dimensioned with respect to an extension of the base 9 between the seat shoulder 21 and an engagement end 27 of the tabs 17 with the engagement surfaces 33 thereon, such that, when the base 9 is rotated so that the engagement surfaces 33 seat upon the tallest portion of the ramps 20, a combined stack dimension is provided where the seat shoulder 21 of the base 9 seats against the distal side of the hub 13.

[0021] Once the base retainer 23 is fully rotated to align fastener holes 29 of the base retainer 23 with retainer sockets 30 of the hub 13, fasteners 31 may be applied therethrough to rotationally secure the base 9 and thereby the feed assembly 1 securely upon the hub 13. Because the fasteners 31 have only a rotational lock requirement with respect to the base retainer 23, the number of and tightening specification for the fasteners 31 may be reduced.

[0022] The engagement surface 33 of the tabs 17 may be provided with an angle corresponding to an angle of the ramps 20, for ease of engagement between the engagement surfaces 33 of the tabs 17 and the ramps 20. Final engagement considerations driving the selected stack dimension may include, when the base retainer 23 is fully rotated to align fastener holes 29 of the base retainer 23 with fastener sockets 30 of the hub 13, the base 9 is drawn toward the hub 13 a distance selected to compress any RF seals (not shown, but applied, for example, to a proximal end of the hub 13) a desired dimension suitable for sealing but less than a dimension which might crush the RF seals. The symmetrical engagement between the tabs 17 and base retainer 23 also stabilizes the base 9 squarely with respect to the hub 13, preventing, for example, the over-tightening of a single fastener 31 from skewing the alignment of the base 9 with respect to the hub 13.

[ 0023 ] One skilled in the art will appreciate that the key feature 15 engagement between the base 9, hub 13, and base retainer 23 enables simplified assembly of the reflector antenna with improved precision, a reduction in the number of required fasteners 31 , a reduction in the required training of assembly personnel, and a shorter overall assembly-time requirement.

[ 0024 ] Referring to the alternative embodiment of FIGs. 6 and 7, base 9a of an alternative feed assembly (analogous to feed assembly 1 of FIG. 1 ) is configured within feed hole 1 1 (FIG. 2) of hub 13 in a manner analogous to the configuration of base 9 within feed hole 1 1 , as described for the previous embodiment, and secured in place using alternative base retainer 23a.

[ 0025 ] As shown in FIG. 8, in addition to tabs 17a, which are analogous to tabs 17 of the previous embodiment, base 9a also has an annular groove 40a.

[ 0026 ] As shown in FIG. 9, base retainer 23a has two opposing clips 42a that engage (e.g., in a snap-fit manner) with the annular groove 40a in base 9a to maintain the axial position of base 9a within feed hole 1 1 of hub 13. Base retainer 23a also has two opposing pairs of bias springs 44a that engage (e.g., in a snap-fit manner) with cylindrical structures 46 on hub 13, as best shown in FIG. 6, to maintain the rotational orientation of base 9a within feed hole 1 1 .

[ 0027 ] As best shown in FIG. 6, after base retainer 23a is used to rotate base 9a into position within feed hole 1 1 of hub 13, two fasteners (not shown, although analogous to fastener 31 of FIG. 1 ) are applied through opposing fastener holes 29a in base retainer 23a into opposing retainer sockets 30 (FIG. 7) of the hub 13 to secure base 9a in place within feed hole 1 1 .

[ 0028 ] Base retainer 23a also have four alignment structures 47a having curved surfaces that rest on the outer surface of the base 9a, as best shown in FIG. 6, to help align the axis of the feed assembly with the centerline of the antenna reflector dish.

[ 0029 ] As indicated in FIG. 9, base retainer 23a, which may be formed from a single piece of molded plastic or metal, may be said to have a central element 48a and two opposing wing elements 52a, where the central element 48a has a retainer hole 50a. [0030] Where, in the foregoing description, reference has been made to materials, ratios, integers, or components having known equivalents, then such equivalents are herein incorporated as if individually set forth.

[0031] While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant's general inventive concept. Further, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.

[0032] Unless explicitly stated otherwise, each numerical value and range should be interpreted as being approximate as if the word "about" or "approximately" preceded the value or range.

[0033] In this specification including any claims, the term "each" may be used to refer to one or more specified characteristics of a plurality of previously recited elements or steps. When used with the open-ended term "comprising," the recitation of the term "each" does not exclude additional, unrecited elements or steps. Thus, it will be understood that an apparatus may have additional, unrecited elements and a method may have additional, unrecited steps, where the additional, unrecited elements or steps do not have the one or more specified characteristics.

[0034] The use of figure numbers and/or figure reference labels in the claims is intended to identify one or more possible embodiments of the claimed subject matter in order to facilitate the interpretation of the claims. Such use is not to be construed as necessarily limiting the scope of those claims to the embodiments shown in the corresponding figures.

[0035] Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the

embodiment can be included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term "implementation."

[ 0036 ] The embodiments covered by the claims in this application are limited to embodiments that (1 ) are enabled by this specification and (2) correspond to statutory subject matter. Non-enabled embodiments and embodiments that correspond to non-statutory subject matter are explicitly disclaimed even if they fall within the scope of the claims.

Claims

CLAIMS What is claimed is:

1 . An article of manufacture comprising a base retainer for securing a feed assembly to a hub for an antenna reflector, the base retainer comprising:

a central element having a retainer hole configured to receive a base of the feed assembly, wherein the retainer hole has one or more key features that engage one or more corresponding key features of the base of the feed assembly to prevent axial rotation of the feed assembly with respect to the base retainer; and

two wing elements, each extending radially from the central element and having structure for securing the base retainer to the hub.

2. The invention of claim 1 , wherein the one or more key features of the base of the feed assembly comprise a plurality of radially extending tabs.

3. The invention of any of claims 1 -2, wherein the base has a seat shoulder which abuts a side of the hub, when the base is secured to the hub.

4. The invention of any of claims 1 -3, wherein:

the hub has a feed hole configured to receive the base of the feed assembly; and the feed hole has one or more key features that correspond to the one or more key features of the base of the feed assembly that enable (i) the base of the feed assembly to be inserted into the feed hole at a first rotational orientation between the feed assembly and the hub and (ii) the base of the feed assembly to be secured in a fixed axial position with respect to the hub at a second rotational orientation between the feed assembly and the hub, different from the first rotational orientation.

5. The invention of claim 4, wherein the base retainer is configured to be used to rotate the feed assembly with respect to the hub from the first rotational orientation to the second rotation orientation by applying rotational torque to the two wing elements.

6. The invention of any of claims 3-4, wherein the feed hole in the hub has one or more ramps configured to draw the base of the feed assembly further into the feed hole as the feed assembly is rotated from the first rotational orientation to the second rotational orientation.

7. The invention of claim 6, wherein an RF seal exists between the base of the feed assembly and the hub after drawing the base further into the feed hole.

8. The invention of any of claims 1 -7, wherein the base retainer has one or more fastener holes for receiving fasteners used to secure the base retainer to the hub.

9. The invention of any of claims 1 -8, wherein each wing element has bias springs that engage structure on the hub to maintain a rotation orientation between the base retainer, the feed assembly, and the hub.

10. The invention of any of claims 1 -9, wherein the base retainer has one or more clips configured to engage an annular groove in the base of the feed assembly to maintain an axial position of the feed assembly with respect to the hub.

1 1 . The invention of any of claims 1 -10, wherein the base retainer has one or more alignment structures configured to maintain an axial alignment between the feed assembly and the antenna reflector.

12. The invention of any of claims 1 -1 1 , wherein the article of manufacture is the base retainer.

13. The invention of any of claims 1 -12, wherein the article of manufacture is the feed assembly secured to the hub using the base retainer.

14. The invention of any of claims 1 -13, wherein the article of manufacture is an antenna comprising the feed assembly secured to the hub using the base retainer and the hub secured to the antenna reflector.

15. A method for securing a feed assembly to a hub for an antenna reflector, the method comprising:

(a) inserting a base of the feed assembly into a feed hole in the hub at a first rotational orientation between the feed assembly and the hub;

(b) using a base retainer to rotate the feed assembly with respect to the hub from the first rotation orientation to a second rotational orientation between the feed assembly and the hub, wherein the first rotational orientation is different from the second rotational orientation;

(c) securing the base retainer to the hub to secure the feed assembly in place with the second rotational orientation.

16. The invention of claim 15, wherein the base retainer comprises:

a central element having a retainer hole configured to receive the base of the feed assembly, wherein the retainer hole has one or more key features that engage one or more corresponding key features of the base of the feed assembly to prevent axial rotation of the feed assembly with respect to the base retainer; and

17. The invention of any of claims 15-16, wherein the feed hole has one or more key features that correspond to the one or more key features of the base of the feed assembly that enable (i) the base of the feed assembly to be inserted into the feed hole at the first rotational orientation between the feed assembly and the hub and (ii) the base of the feed assembly to be secured in a fixed axial position with respect to the hub at the second rotational orientation between the feed assembly and the hub.

18. The invention of claim 17, wherein step (b) comprises applying rotational torque to the two wing elements to rotate the feed assembly with respect to the hub from the first rotational orientation to the second rotation orientation.

19. The invention of any of claims 17-18, wherein the feed hole in the hub has one or more ramps configured to draw the base of the feed assembly further into the feed hole as the feed assembly is rotated from the first rotational orientation to the second rotational orientation.

20. The invention of claim 19, wherein step (b) forms an RF seal between the base of the feed assembly and the hub as the base is drawn further into the feed hole.