Additive Manufacturing Cluster Feed

Abstract

Described herein are apparatus and methods for a cluster connector that includes at least three coaxial cable core conductors formed by an additive manufacturing process, a dielectric around each of the three coaxial cable core conductors formed by an additive manufacturing process, a metal shield around each dielectric formed by an additive manufacturing process, at least one stub on each metal shield formed by an additive manufacturing process, and a common ground connection connected to each metal shield formed by an additive manufacturing process.

Description

[Background technology]

[0001] Ultra-wideband (UWB) radio frequency (RF) antennas are limited by the bandwidth of the feed network. UWB antennas with direction-sensing capabilities have not yet been fully additively manufactured. Summary of the Invention

[0002] In accordance with the concepts described herein, an exemplary additively manufactured cluster connector and its manufacturing method provides one-step printing fabrication of monolithic phase-matched RF cluster connectors suitable for use in UWB electronic systems.

[0003] In accordance with the concepts described herein, the exemplary additively manufactured cluster connector and its manufacturing method eliminates the multiple manufacturing steps required to assemble an RF cluster connector by conventional methods.

[0004] In accordance with the concepts described herein, exemplary additively manufactured cluster connectors and methods for their manufacture provide additively manufactured (e.g., 3D printed) cluster connectors that are not manufacturable by conventional methods.

[0005] In accordance with the concepts described herein, exemplary additively manufactured cluster connectors and their manufacturing methods provide inexpensive, lightweight, rapidly prototypeable cluster connectors that have size and electronic performance comparable to or superior to their conventionally manufactured counterparts.

[0006] In accordance with the concepts described herein, the exemplary additively manufactured cluster connector and its manufacturing method provides a cluster connector that can be monolithically integrated with other modules in an electronic assembly and manufactured as a unit with those modules.

[0007] In accordance with the concepts described herein, exemplary additively manufactured cluster connectors and methods provide cluster connectors that reduce the number of separate parts that need to be manufactured into a system.

[0008] The methods and processes for making and using the disclosed embodiments may be understood by reference to the figures in the accompanying drawings. It should be understood that the components and structures shown in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the concepts described herein. Like reference characters designate corresponding parts throughout the different views. Moreover, embodiments are illustrated in the drawings by way of example, and not by way of limitation. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of an exemplary embodiment of a cluster connector. [Figure 2] FIG. 2 is a top view of the cluster connector of FIG. 1. [Figure 3] 2 is a side cross-sectional view of one coaxial connector in the cluster connector of FIG. 1. [Figure 4] 2 is a perspective view of a flared stub of one of the coaxial connectors of the cluster connector of FIG. 1. FIG. [Figure 5] FIG. 1 is a top perspective view of an exemplary embodiment of a cluster connector. [Figure 6] FIG. 6 is a side perspective view of an exemplary embodiment of the cluster connector of FIG. 5. [Figure 7] FIG. 6 is a side view of the stub of the cluster connector of FIG. 5. [Figure 8] 1 is a perspective view of an exemplary embodiment of a cluster connector in which the coaxial connectors are bent; [Figure 9] 9 is a perspective view of the cluster connector of FIG. 8 with a cavity and an absorber. [Figure 10] 1 is a flowchart of a method for manufacturing an exemplary embodiment of a cluster connector. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present disclosure provides a fully additively manufactured (e.g., 3D printed) phase-matched cluster connector. In an exemplary embodiment, the present disclosure provides a flared or tapered stub that can be used to obtain UWB RF response. The exemplary cluster connector of the present disclosure can be used as a feed network for a very large bandwidth antenna.

[0011] In an exemplary embodiment, the cylindrical connectors are arranged in a ring configuration and attached to a common ground at the center of the ring. Three or more connectors may be arranged in this manner for multi-mode operation of the direction-sensing antenna.

[0012] In an exemplary embodiment, the stub, which cannot be machined by conventional manufacturing methods (eg, a radially flared stub), is designed to operate over a wide bandwidth.

[0013] The present disclosure discloses a coaxial cluster (e.g., ≥ three coaxial connectors or coaxial cables) that can be used as a feed to a monolithically integrated antenna that can also sense angular direction of arrival. Sensing two polar coordinates that completely define a direction in hemispherical space requires at least three coaxial connectors (or coaxial cables). A two-coaxial cable spiral antenna cannot be used to sense two polar coordinates; at least three coaxial cables are required. The present disclosure discloses a cluster connector that can sense angular position in a monolithic manufacturing system. It is of interest to UWB systems for utilizing the spectrum available for microwave and millimeter-wave frequencies. The present disclosure discloses a cluster connector that provides a phase-matched (e.g., no phase aberration due to the symmetry of the arrangement) feed to a direction-finding (DF) system.

[0014] 1 and 2 are a perspective view and a top view, respectively, of an exemplary embodiment of a cluster connector 100. In the exemplary embodiment, the cluster connector 100 includes four coaxial connectors, each including a core conductor 101, a dielectric 103 surrounding the core conductor 101, a metal shield 105 surrounding the dielectric 103, and two stubs 107. A ground connection 109 (e.g., a common ground connection) may be located in the center of the four coaxial connectors or may be connected to each of the four coaxial connectors.

[0015] Each coaxial connector may be rotated 90 degrees from the orientation of the adjacent coaxial connector. However, the present disclosure is not limited to four coaxial connectors, two stubs 107 per coaxial connector, the specific length of each coaxial connector, the specific shape of each coaxial connector, the arrangement of stubs 107 shown in FIG. 1 , or the + / - 90 degree rotation between adjacent coaxial connectors. The present disclosure may have three or more coaxial connectors, one or more stubs 107, any suitable shape, any suitable arrangement of stubs 107, and any suitable rotation between adjacent coaxial connectors. When there are at least three coaxial connectors, the present disclosure may be used in DF applications.

[0016] The number of coaxial connectors, the number of stubs per coaxial connector, the length of each coaxial connector, the shape of each coaxial connector, the placement of the stubs 107, and the degree of rotation between adjacent coaxial connectors depend on the operating frequency of the attached antenna (e.g., individual antennas, beamforming antennas, etc.) and whether any dielectric material is present (e.g., whether the air dielectric properties are close to free space). The wavelength in free space is equal to the speed of light divided by the frequency. The length of the stubs 107 may be approximately 1 / 4 of the wavelength calculated at the center operating frequency. If other dielectric materials are present, the wavelength is equal to the speed of light divided by the square root of the dielectric constant of the dielectric material multiplied by the frequency. Therefore, the range of stub 107 lengths depends on the frequency for which the cluster connector 100 can be designed. The spacing between the stubs 107 depends on which spacing minimizes reflections. The number of stubs can be based on the wide bandwidth required for the application.

[0017] 3 is a cross-sectional side view of one coaxial connector in the cluster connector 100 of FIG. 1. In the exemplary embodiment, two stubs 107 are shown, the two stubs 107 being on opposite sides of the metal shield 105 and at different locations along the length of the coaxial connector. Each stub 107 comprises a conductive (e.g., metallic) material and connects to the metal shield 105 of one of the coaxial connectors of the cluster connector 100. However, the present disclosure is not limited to the number or arrangement of stubs 107 in FIG. 3. Any suitable number and any suitable arrangement of stubs 107 may be used.

[0018] The stubs 107 allow the cluster connector 100 to be phase-matched to antennas (e.g., individual antennas, beamforming antennas, etc.) connected to the cluster connector 100. The stubs 107 may be flared. However, the present disclosure is not limited to such shapes. Other shapes may also be used.

[0019] FIG. 4 is a perspective view of the flared stub 107 of each coaxial connector of the cluster connector 100 of FIG. 1. At a quarter-wavelength distance in the transmission line, a short circuit appears as an open circuit to the incoming wave. This occurs at a single frequency. For ultra-wideband applications, the stub 107 may be exponentially tapered at the short post (e.g., the metal shield 105 of the coaxial connector of the cluster connector 100). However, this disclosure is not limited to the exponential taper of the stub 107. For non-narrowband applications, other tapers may be used to provide a quarter-wavelength over a frequency range (e.g., linear, triangular, exponential, and Klopfenstein tapers are possible). The Klopfenstein taper has a profile that achieves a specified match over the shortest length and is based on a Chebychev filter design. Three-dimensional flares are difficult to machine using conventional manufacturing but are readily fabricated using additive manufacturing processes (e.g., 3D printing, including stereolithography (SLA), direct light processing (DLP), and / or powder bed fusion bonding). The length of the stubs 107 (e.g., short stubs), the number of stubs 107, and the spacing between the stubs 107 are electrical parameters that work in conjunction to achieve good phase matching to the attached antenna.

[0020] 5 and 6 are top and side perspective views, respectively, of an exemplary embodiment of a cluster connector 500. In the exemplary embodiment, the cluster connector 500 includes four coaxial connectors, each including a core conductor 501, a dielectric 503 surrounding the core conductor 501, a metal shield 505 surrounding the dielectric 503, and two stubs 507. A ground connection 509 (e.g., a common ground connection) may be located in the center of the four coaxial connectors or may be connected to each of the four coaxial connectors. The four coaxial connectors are as described above with respect to FIGS. 1 and 2, except for the shape of the stubs 507. In FIGS. 5 and 6, the stubs 507 are cylindrical. However, the present disclosure is not limited thereto.

[0021] 7 is a side view of stubs 507 of cluster connector 500 of FIG. 5. In an exemplary embodiment, each stub 507 and each metal shield has a surface roughness. For additively manufactured components that carry electromagnetic (EM) waves, the surface roughness (e.g., the average height / depth of the troughs and valleys in the surface) should be on the order of the skin depth. The skin depth is the depth of maximum current concentration at a particular frequency. In an exemplary embodiment, the metal shield and stubs 507 may have an arithmetic mean roughness (RA) of 200 microinches to 400 microinches (e.g., 5-10 microns).

[0022] In an embodiment, each stub 507 includes two surface finishes: an exterior finish and an interior finish. In an embodiment, the exterior finish may be a high polish finish (e.g., a mirror finish) of approximately 600 grit. However, the present disclosure is not limited thereto. The interior finish may have an RA of 200 microinches to 400 microinches (e.g., 5-10 microns). However, the present disclosure is not limited thereto.

[0023] FIG. 8 is a perspective view of an exemplary embodiment of a cluster connector 800 in which the coaxial connectors are bent. In the exemplary embodiment, the cluster connector 800 includes four bent coaxial connectors, each of which includes a core conductor 801, a dielectric 803 surrounding the core conductor 801, a metal shield 805 surrounding the dielectric 803, and three stubs 807. A ground connection 809 (e.g., a common ground connection) may be located in the center of the four bent coaxial connectors or may be connected to each of the four bent coaxial connectors. An additional connector 811 may be connected to each end of the bent coaxial connectors of the cluster connector 800. In the exemplary embodiment, the additional connector 811 may also be connected to the other end of the bent coaxial connectors of the cluster connector 800.

[0024] Each bent coaxial connector may be rotated 90 degrees from the orientation of an adjacent bent coaxial connector. However, the present disclosure is not limited to four bent coaxial connectors, three stubs 807 per bent coaxial connector, the specific length of each bent coaxial connector, the specific shape of each bent coaxial connector, the arrangement of stubs 807 shown in FIG. 8 , or the 90-degree rotation between adjacent bent coaxial connectors. The present disclosure may have three or more bent coaxial connectors, one or more stubs 807, any suitable shape, any suitable arrangement of stubs 807, and any suitable rotation between adjacent coaxial connectors. When there are at least three coaxial connectors, the present disclosure may be used in DF applications.

[0025] Figure 9 is a perspective view of the cluster connector 800 of Figure 8 with a cavity 901 and an absorber 903. In an exemplary embodiment, the cluster connector 800 is as described above, but with a cavity 901 surrounding the cluster connector 800, and with the cavity 901 being half-filled with an absorber 903.

[0026] The cavity 901 may be cylindrical with openings at each end to allow a bent coaxial connector to pass through. However, the present disclosure is not limited to cylindrical cavities. Other shapes (e.g., square, rectangular, octagonal, etc.) are also possible. The absorber 903 may be a broadband absorber that provides insertion loss from 1 to 18 GHz. In an exemplary embodiment, the absorber 903 is made from an absorber sheet sold by Mast Technologies (masttechnologies.com) and has SKU MF22-0009-00. It may absorb one of two lobes / bidirectional radiation response. The absorber 903 fills half of the cavity 901. However, the present disclosure is not limited in this respect. The absorber 903 may fill more or less than 50% of the metal cavity enclosing the antenna. The absorber 903 may be cut into a cylindrical shape that fits into the cavity 901. Any other broadband absorber may be used. If a broadband absorber is not available, narrowband absorbers may be stacked to generate a broadband response. The absorbing material of the absorber 903 may absorb all radiation directed toward the cavity 901. Since the antenna may be broadband, the absorbing characteristics of the absorbing material of the absorber 903 may be broadband. Otherwise, reflections from the cavity 901 may impair radiation performance. The cavity 901, cluster connector 800, and antenna may be additively manufactured as a single metal part. In an exemplary embodiment, the cavity 901, cluster connector 800, beamforming network, and antenna may be additively manufactured as a single metal part.

[0027] 10 is an exemplary embodiment of a method for manufacturing a cluster connector. In the exemplary embodiment, method 1000 includes forming core conductors for at least three coaxial conductors in an additive manufacturing process in step 1001.

[0028] Step 1003 includes forming a dielectric around each core conductor in an additive manufacturing process. Step 1005 includes forming a metal shield around each dielectric in an additive manufacturing process. Step 1007 includes forming at least one stub on each metal shield in an additive manufacturing process. Step 1009 includes forming a common ground connection to each metal shield in an additive manufacturing process.

[0029] Although illustrative embodiments of the present disclosure have been described, it will be apparent to those skilled in the art that other embodiments incorporating these concepts may also be used. The embodiments contained herein should not be limited to the disclosed embodiments, but rather should be limited only by the spirit and scope of the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.

[0030] Elements of different embodiments described herein can be combined to form other embodiments not specifically described above. Various elements described in the context of a single embodiment may be provided separately or in any suitable subcombination. Other embodiments not specifically described herein are also within the scope of the following claims.

[0031] Various embodiments of the concepts, systems, devices, structures, and techniques for which protection is sought are described herein with reference to the associated drawings. As noted above, in embodiments, the concepts and features described herein may be embodied in a digital multi-beam beamforming system. Alternative embodiments may be contemplated without departing from the scope of the concepts, systems, devices, structures, and techniques described herein.

[0032] It should be noted that in the above description and drawings, various connections and relationships (e.g., above, below, adjacent, etc.) are described between elements. These connections and / or relationships may be direct or indirect unless otherwise specified, and the described concepts, systems, devices, structures, and techniques are not intended to be limiting in this regard. Thus, coupling of entities can refer to direct or indirect coupling, and relationship between entities may be direct or indirect relationship.

[0033] As an example of an indirect positional relationship, reference in this description to forming layer "A" on layer "B" includes the situation where one or more intermediate layers (e.g., layer "C") are between layer "A" and layer "B," so long as the relevant properties and functions of layer "A" and layer "B" are not substantially altered by the intermediate layer(s). The following definitions and abbreviations shall be used in interpreting the claims and the specification. As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, mixture, process, method, article, or device that includes a list of elements is not necessarily limited to only those elements and may include other elements not expressly listed or other elements inherent to such composition, mixture, process, method, article, or device.

[0034] Additionally, the term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms "one or more" and "one or more" are understood to include any integer number greater than or equal to one, i.e., 1, 2, 3, 4, etc. The term "plurality" is understood to include any integer number greater than or equal to two, i.e., 2, 3, 4, 5, etc. The term "connected" can include indirect and direct "connections."

[0035] References in the specification to "one embodiment," "an embodiment," "an exemplary embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but that all embodiments may include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is believed to be within the knowledge of one of ordinary skill in the art to affect such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly stated.

[0036] For purposes of this description, the terms "above," "below," "right," "left," "vertical," "horizontal," "top," "bottom" (to name a few) and their derivatives refer to the structures and methods described, as well as the orientation of the drawings. The terms "overlying," "atop," "on top," "positioned on," or "positioned atop" mean that a first element, such as a first structure, is above a second element, such as a second structure, and intervening elements, such as interfacial structures, may be present between the first and second elements. The term "direct contact" means that a first element, such as a first structure, and a second element, such as a second structure, are connected without intervening elements. Such terms may also be referred to as directional or positional terms.

[0037] The use of ordinal numbers such as "first," "second," "third," etc. in the claims to modify claim elements does not, in itself, imply a priority, precedence, or ordering of one claim element relative to other claim elements, or a chronological order in which method actions are performed, but is merely used as a label to distinguish one claim element with a particular name from another element with the same name (other than the use of the ordinal number) to distinguish between claim elements.

[0038] It is to be understood that the disclosed subject matter is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings, as the disclosed subject matter is capable of other embodiments and of being practiced and carried out in various ways.

[0039] It is also to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Thus, those skilled in the art will appreciate that the conception underlying the present disclosure may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out some of the purposes of the disclosed subject matter. Accordingly, the claims should be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the disclosed subject matter.

[0040] While the disclosed subject matter has been described and illustrated in the foregoing exemplary embodiments, it should be understood that the disclosure is made by way of example only, and that numerous changes may be made in the details of the implementation of the disclosed subject matter without departing from the spirit and scope of the disclosed subject matter.

Claims

1. at least three coaxial cable core conductors; a dielectric surrounding each of the at least three coaxial cable core conductors; a metal shield around each dielectric; at least one stub on each metal shield; a common ground connection connected to each metallic shield; Additively manufactured cluster connector.

2. 10. The additively manufactured cluster connector of claim 1, wherein the at least three coaxial cable core conductors, the dielectric, the metal shield, the at least one stub, and the common ground connection are manufactured using three-dimensional (3D) printing, the 3D printing comprising stereolithography (SLA), direct light processing (DLP), and / or powder bed fusion bonding.

3. 10. The additively manufactured cluster connector of claim 1, wherein said at least one stub flares with a taper in a radial direction of said at least one stub.

4. 4. The additively manufactured cluster connector of claim 3, wherein the taper is one of exponential, triangular, or Klopfenstein.

5. 10. The additively manufactured cluster connector of claim 1, wherein the at least one stub has a length of about 1 / 4 of a calculated wavelength at a center operating frequency of an antenna connected to the cluster connector.

6. 10. The additively manufactured cluster connector of claim 1, wherein the at least one stub on one metal shield comprises two stubs oriented on opposite sides of the metal shield, and the stubs on adjacent metal shields are oriented + / - 90 degrees from each other.

7. 10. The additively manufactured cluster connector of claim 1, wherein the at least one stub and the metal shield each have an arithmetic average roughness (RA) of 5 to 10 microns.

8. 10. The additively manufactured cluster connector of claim 1, wherein the at least three coaxial cable core conductors are bent.

9. Cavity and An absorber; further comprising:

10. The additively manufactured cluster connector of claim 1.

10. forming core conductors of at least three coaxial cables using an additive manufacturing process; forming a dielectric around each core conductor using an additive manufacturing process; forming a metal shield around each dielectric using an additive manufacturing process; forming at least one stub on each metal shield using an additive manufacturing process; and forming a common ground connection to each metal shield using an additive manufacturing process. A method for manufacturing a cluster connector.

11. 11. The method of claim 10, wherein the additive manufacturing process used to form the core conductor, the dielectric, the metallic shield, the at least one stub, and the common ground connection for each of the at least three coaxial cables is a three-dimensional (3D) printing process including at least one of stereolithography (SLA), direct light processing (DLP), and powder bed fusion bonding.

12. The method of claim 10 , wherein the at least one stub is flared with a taper in a radial direction of the at least one stub.

13. The method of claim 12 , wherein the taper is one of exponential, triangular, or Klopfenstein.

14. The method of claim 10 , wherein the at least one stub has a length of approximately one-quarter of a calculated wavelength at a center operating frequency of an antenna connected to the cluster connector.

15. 11. The method of claim 10, wherein the at least one stub on one metal shield includes two stubs oriented on opposite sides of the metal shield, and the stubs on adjacent metal shields are oriented + / - 90 degrees from each other.

16. The method of claim 10, wherein the at least one stub and the metal shield each have an arithmetic average roughness (RA) of 5 to 10 microns.

17. The method of claim 10 , wherein the at least three coaxial cables are bent.

18. forming a cavity using an additive manufacturing process; and filling at least a portion of the cavity with an absorbent material. The method of claim 10.

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