Patent Application
20240387972
The disclosure is in the field of electrical transmission lines.
Additively-manufactured overhanging surfaces can cause degraded performance when using tuners to support a central conductor of an electrical transmission line. Examples of such degraded performance are electrical losses, higher-order mode propagation, and signal reflections.
An additively-manufactured electrical transmission line is configured to allow surface treatment of even interior surfaces, after formation.
According to an aspect of the disclosure, an electrical transmission line includes: an outer housing defining a cavity therewithin; a conductive stripline passing through the cavity; and stubs within the cavity electrically coupling the outer housing to the stripline; wherein the outer housing, the stripline, and the stubs are all parts of a single unitary continuous monolithic additively-manufactured transmission line.
According to an embodiment of any paragraph(s) of this summary, the stubs are angled at an acute angle relative to a direction of extent of the conductive stripline.
According to an embodiment of any paragraph(s) of this summary, the stripline is flat.
According to an embodiment of any paragraph(s) of this summary, the stripline has a rectangular cross section.
According to an embodiment of any paragraph(s) of this summary, transmission line ends of the stripline have a circular cross section, with transition regions between the rectangular cross section and the transmission line ends.
According to an embodiment of any paragraph(s) of this summary, the stripline has transmission line ends at opposite ends of the stripline.
According to an embodiment of any paragraph(s) of this summary, the outer housing narrows around the transmission line ends, defining narrowed passages that are in fluid connection with the cavity.
According to an embodiment of any paragraph(s) of this summary, the stubs have an angle of between 30 and 60 degrees to the stripline.
According to an embodiment of any paragraph(s) of this summary, the stubs have an angle of between 40 and 50 degrees to the stripline.
According to an embodiment of any paragraph(s) of this summary, the stubs extend off opposite sides of the stripline.
According to an embodiment of any paragraph(s) of this summary, the stubs are staggered, alternating between the opposite sides in a longitudinal direction along the stripline.
According to an embodiment of any paragraph(s) of this summary, the stubs have convex opposite streamlined surfaces that facilitate flow past the stubs.
According to an embodiment of any paragraph(s) of this summary, air in the cavity functions as a dielectric around the stripline.
According to an embodiment of any paragraph(s) of this summary, the electrical transmission line is non-straight.
According to an embodiment of any paragraph(s) of this summary, the electrical transmission line is (or is part of) a connector.
According to an embodiment of any paragraph(s) of this summary, the electrical transmission line is (or is part of) a cable.
According to another aspect of the disclosure, an electrical installation between a pair of devices includes: electrical conductors coupling conductors of one of the devices with conductors of the other of the devices, the electrical conductors each including: an outer housing defining a cavity therewithin; a conductive stripline passing through the cavity; and stubs within the cavity electrically coupling the outer housing to the stripline; wherein the outer housing, the stripline, and the stubs are all parts of a single unitary continuous monolithic additively-manufactured transmission line; wherein at least some of the electrical conductors are non-straight electrical conductors.
According to yet another aspect of the disclosure, a method of making an electrical transmission line, the method comprising: additively forming, as a single piece, the electrical conductor including: an outer housing defining a cavity therewithin; a conductive stripline passing through the cavity; and stubs electrically coupling the outer housing to the stripline; and treating internal surfaces of the outer housing, the conductive stripline, and the subs, to reduce surface roughness.
According to an embodiment of any paragraph(s) of this summary, the additively forming includes powdered bed forming.
According to an embodiment of any paragraph(s) of this summary, the additively forming includes laser powdered bed forming.
According to an embodiment of any paragraph(s) of this summary, the additively forming includes forming the electrical conductor in a longitudinal direction.
According to an embodiment of any paragraph(s) of this summary, the treating includes abrasive flow machining of the internal surfaces.
According to an embodiment of any paragraph(s) of this summary, the abrasive flow machining includes passing a fluid with abrasive material back and forth through the cavity.
While a number of features are described herein with respect to embodiments of the disclosure; features described with respect to a given embodiment also may be employed in connection with other embodiments. The following description and the annexed drawings set forth certain illustrative embodiments of the disclosure. These embodiments are indicative, however, of but a few of the various ways in which the principles of the disclosure may be employed. Other objects, advantages, and novel features according to aspects of the disclosure will become apparent from the following detailed description when considered in conjunction with the drawings.
The annexed drawings, which are not necessarily to scale, show various aspects of the disclosure.
An additively-manufactured electrical transmission line is made as a single, unitary continuous monolithic additively-manufactured piece of material, including an outer housing defining a cavity therewithin, a conductive stripline passing through the cavity, and stubs within the cavity electrically coupling the outer housing to the stripline. The stripline may be a flat stripline. The stubs may be angled relative to the stripline, to facilitate surface treatment within the housing, such as abrasive flow machining to reduce surface roughness, which may be part of a method of making the electrical transmission line. The electrical transmission line may be part of an electrical installation including multiple such electrical transmission lines, which may have shapes, including curved shapes, for making desired electrical connections between components.
The electrical transmission line 10 is a single-piece additively manufactured piece. The electrical transmission line 10 includes a housing 12 that surrounds and defines a central cavity 14 in it. A stripline 16 runs through the cavity 14, from a first end 22 of the transmission line 10 to an opposite (second) end 24 of the transmission line 10. The stripline 16 is electrically (and physically) connected to the housing 12 by a series of stubs 26 running between the stripline 16 and the housing 12, within the cavity 14.
Details are now given regarding the illustrated embodiment of the electrical transmission line 10 shown in
The housing 12 may have a wider central portion 28, with narrower end portions 32 and 34. The central portion 28 may be rectangular, and the end portions 32 and 34 may have circular cross sections. There may be transitions 36 and 38 between the different shapes of the central portion 28, and the respective end portions 32 and 34.
The cavity 14 has a wider central region 40 and narrower end regions 42 and 44, with tapering transition regions 46 and 48 between the central region 40 and the respective end regions 42 and 44. The central region 40 may have a rectangular shape, bounded by flat inner walls of the housing central portion 28, and the end regions 42 and 44 may be bounded by rounded inner walls of the housing end portions 32 and 34. The transition regions 46 and 48 of the cavity 14 are defined by curved housing inner surfaces, between the flat walls of the central region 40 and the end regions 42 and 44. This facilitates flow of fluid material through the cavity 14, such as for post-formation surface treatment to reduce roughness of the inner surface of the housing 12 that defines the cavity 14. The end regions 42 and 44 may be narrowed annular passages that are in fluid communication with the central region 40.
The stripline 16 includes a flat central section 50 and round ends 52 and 54. Transition regions 56 and 58 gradually vary the shape of the stripline from the flat central section 50, with its rectangular cross section, and stripline ends 52 and 54.
The stubs 26 have a herringbone pattern, extending from alternate sides of the stripline central section 50 (when considered from the standpoint of a longitudinal direction along the stripline 16) to the inner walls of the housing central portion 28. The stubs 26 provide a physical and electrical connection between the stripline 16 and the housing 12. The stubs 26 are angled relative to the stripline central section 50. This angling may facilitate flow of abrasive material through the cavity 14, for example to reduce surface roughness after formation of the electrical transmission line 10.
The stubs 26 may be about a 45 degree angle to an longitudinal extent of the stripline central section 50. More broadly the stubs 26 may be at angle of from 40 to 50 degrees, or from 30 to 60 degrees, to the longitudinal extent of the stripline 16.
The stubs 26 may have a rectangular cross-section shape. Alternatively, as described further below, the stubs 26 may have a cross section shape that facilitates flow of abrasive fluid material past them, such as a tapered shape that is thicker in the middle and thinner on the edges.
The stubs 26 provide a short-circuit coupling between the stripline 16 and the housing 12. The stubs 26 may be configured in conjunction with the air-filled (dielectric) spaces around the stripline 16 to achieve desired electrical performance in the electrical transmission line 10. For example the configuration may achieve desired isolation from radio frequency (RF) interference. Alternatively or in addition, spaces around the stripline 16 may be filled with other dielectric materials, such as (for example) suitable powders, liquids, or resins.
The electrical transmission line 10 may be made out of any of a variety of suitable materials. Examples of suitable electrically-conductive materials include metals, such as aluminum or titanium; metal alloys, such as aluminum-based alloys, for example A205, and such as nickel-based alloys marketed under the trademark INCONEL; and metal-coated polymers.
The electrical transmission line 10 may be produced in an additive manufacturing process, for example being formed by a powder bed fusion method. In such a method selective heating, such as from a laser or electron beam, is used to fuse (sinter) portions of a bed of powdered raw material, with the electrical transmission line 10 built up layer by layer. The electrical transmission line 10 may be built up in a vertical direction, such as along a longitudinal direction along the stripline 16.
After the process to additively manufacture the electrical transmission line 10, the transmission line 10 may be subject to treatment to improve its finish. This may include abrasive flow machining, a process in which an abrasive fluid (a fluid containing abrasive particles) is passed through the cavity 14 in either or both directions (from the end 22 to the end 24, and/or from the end 24 to the end 22), perhaps multiple times, in order to obtain a smoother finish even on interior surfaces of the electrical transmission line 10.
The electrical transmission line 10 offers many advantages. The parallel center conductor (the stripline 16) and the ground walls of the housing 12 enables easy vertical printing (additive manufacturing). Rectangular cross section transmission lines avoid downward facing surfaces and thin wall features. The angled configuration of the stubs 26 enables easy printing and minimizes complications that might arise from partial sintering.
In the configuration of the electrical transmission line 10 the herringbone configuration of the stubs 26 conforms with additive manufacturing guidelines. In addition the possibility of partially sintered powder on downward-facing surfaces is minimized. The avoidance of partially sintering of powder reduces the possibility of foreign object damage (FOD) from such partially-sintered powder. Surface finish may be improved, even though no complex machining post-processing steps are needed.
Many variations in configuration are possible. For example the number and configuration of the stubs 26 may be varied to achieve desired wideband performance in the electrical transmission line 10. The stubs 26 also may advantageously provide a robust structural and thermal arrangement for the components of the electrical transmission line 10. High-temperature transmission lines may thus be formed.
Although the disclosure has been shown and described with respect to a certain embodiment or embodiments, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the disclosure. In addition, while a particular feature of the disclosure may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
This patent application claims the benefit of U.S. Provisional Patent Application No. 63/502,734, filed May 17, 2023, which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63502734 | May 2023 | US |
