Patent Application
20210367316
Radio frequency (RF) waveguides are used for conveying radio signals at millimeter band frequencies. At high frequencies (e.g., 30 Gigahertz (GHz) through 140 GHz), a waveguide is considered the only practical signal transmission medium. Examples of applications operating at such high frequencies include automotive radar and 5G wireless communication. For example, automotive applications are requiring increased use of RF/microwave frequency bands, from low RF signals through millimeter-wave frequencies at 75-90 GHz. As these high-frequency signals become more integral parts of the worldwide driving experience, effective test solutions become more critical for designers developing new automotive RF/microwave circuits, as well as production facilities seeking efficient methods for verifying the performance of these added circuits. A growing concern in automotive markets is for the accurate and cost-effective testing of 75-90 GHz automotive radar systems. This interest stems from the fact that historically, measurement equipment at such high frequencies has neither been commonplace nor cost-effective.
A number of different automotive radar-based safety applications make use of frequencies from 75-90 GHz, for adaptive cruise control (ACC), blind-spot detection (BSD), emergency braking, forward collision warning (FCW), cross traffic alert (CTA), lane change assist (LCA), and rear collision protection (RCP). For example, in a collision warning system, an automotive radar sensor can detect and track objects within the range of the transmitted and returned radar signals, automatically adjusting a vehicle's speed and distance in accordance with the detected targets. Different systems can provide a warning of a potential collision ahead and also initiate procedures leading to emergency braking as required.
Typical automotive radar chipsets may include dozens of high frequency RF ports dedicated to the various radar-based applications described above. Each of these high frequency RF ports requires performance and production testing. As such, each high frequency RF port requires a dedicated waveguide for conveying signals to and from a test system. As the density of high frequency RF ports increases, the manufacture and customization of waveguides of conventional test equipment becomes increasing impractical and, in some cases, essentially impossible
The accompanying drawings, which are incorporated in and form a part of the Description of Embodiments, illustrate various embodiments of the subject matter and, together with the Description of Embodiments, serve to explain principles of the subject matter discussed below. Unless specifically noted, the drawings referred to in this Brief Description of Drawings should be understood as not being drawn to scale. Herein, like items are labeled with like item numbers.
The following Description of Embodiments is merely provided by way of example and is not intended to be exhaustive or to limit the embodiments to the precise form described. Instead, example embodiments in this Description of Embodiments have been presented in order to enable persons of skill in the art to make and use embodiments of the described subject matter. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding background or in the following Description of Embodiments.
Moreover, various embodiments have been described in various combinations. However, any two or more embodiments can be combined. Although some embodiments have been described in a language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed by way of illustration and as example forms of implementing the claims and their equivalents
Reference will now be made in detail to various embodiments of the subject matter, examples of which are illustrated in the accompanying drawings. While various embodiments are discussed herein, it will be understood that they are not intended to limit to these embodiments. On the contrary, the presented embodiments are intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope the various embodiments as defined by the appended claims. Furthermore, in this Description of Embodiments, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present subject matter. However, embodiments may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the described embodiments.
Some portions of the detailed descriptions which follow are presented in terms of procedures, logic blocks, processing and other symbolic representations of operations for creating or using a manually conformable waveguide. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. In the present application, a procedure, block, process, or the like, is conceived to be one or more self-consistent procedures or instructions leading to a desired result. The procedures are those requiring physical manipulations of physical quantities. Usually, although not necessarily, these quantities take the form of high frequency (e.g., millimeter or microwave) signals capable of being transmitted and received by an electronic device and/or electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in an electrical device.
It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the description of embodiments, discussions utilizing terms such as “receiving,” “bending,” “conforming,” “passing,” “forming,” “conveying,” or the like, refer to the actions and processes of an electric device such as a metal rolling machine.
Discussion begins with a description of an example manually conformable waveguide, in accordance with various embodiments. An example tool for enabling the manual conforming of a manually conformable waveguide is then described. Example operations for manufacturing a manually conformable waveguide are then described.
Embodiments described herein provide a conformable waveguide for conveyance of high frequency radio signals including a hollow component having a smooth interior surface and an obround cross section. An obround cross section is defined as having parallel opposing sides connected by two rounded opposing ends, wherein the parallel opposing sides are separated by a first distance, wherein vertices of the two rounded opposing ends are separated by a second distance, wherein the second distance is greater than the first distance.
In one embodiment, a ratio of the second distance to the first distance is between 1.5/1 and 2/1. In one embodiment, a ratio of the first distance to a thickness of the hollow component is between 10/1 and 20/1. In one embodiment, the two rounded opposing ends have semicircular cross sections. In another embodiment, the two rounded opposing ends have semielliptical cross sections. In another embodiment, the two rounded opposing ends have semioval cross sections. In one embodiment, the parallel opposing sides comprise depressions such that the conformable waveguide has a substantially epitrochoid cross section.
A waveguide is essentially the only practical transmission media of radio signals at millimeter-wave frequencies (e.g., greater than 30 GHz) currently available for use. Other transmission media, such as coaxial cable, have very high loss and very high interconnect cost. As utilized herein, a waveguide is a carefully shaped hollow tube or component that “guides” a radio signal (e.g., radio wave) in the intended direction. The size and shape of the waveguide is critical for the application. Conventionally, a rectangular waveguide is the most practical and most common form of waveguide currently in use, where a rectangular waveguide is rectangular in cross section.
Furthermore, conventional waveguides are a rigid media. Typically, conventional waveguides require design and fabrication to designed specifications. To bend or conform a conventional waveguide, the waveguide must be filled with solid material (e.g., solder), then mandrel bent. After bending, the solid material must somehow be removed. This requires specialized equipment and techniques making conventional waveguides impractical for custom applications.
There are two main issues that render manual bending or forming of rectangular waveguide impractical. First, when bending, the rectangular shape physically distorts, adversely affecting the electrical performance. Second, the wall thickness makes bending difficult, given the geometry of the rectangular cross section. It should be appreciated that these issues are not isolated to rectangular waveguides, but are also observed in waveguides having circular, oval, or elliptical cross sections.
Embodiments described herein provide a new and improved form of waveguide that can easily be manually bent to any shape using only simple hand tools or no tools at all. The waveguide described herein has cross section of a particular obround shape that makes the waveguide bendable without significant distortion, and still preserves electrical performance. An obround waveguide has an obround cross section, generally defined as having rounded ends (e.g., an approximate semicircle) with straight or substantially straight sides in the middle. This shape may also be referred to as a stadium or racetrack, due to the similarity to those shapes. It may also be referred to as a discorectangle. It should be appreciated that the rounded ends may have semicircular cross sections, semielliptical cross sections (including either the major or minor axes), semioval cross sections, or other rounded or curved cross sections. As utilized herein, the term obround includes all of these embodiments.
Embodiments described herein provide a conformable waveguide for conveyance of high frequency radio signals including a hollow component having a smooth interior surface and an obround cross section. One or more embodiments are now described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the various embodiments. It may be evident, however, that the various embodiments can be practiced without these specific details.
As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. In addition, the word “coupled” is used herein to mean direct or indirect electrical or mechanical coupling. In addition, the word “example” is used herein to mean serving as an example, instance, or illustration.
Waveguide 106 can be comprised of any bendable or conformable metal, including and without limitation: copper, aluminum, and brass. In some embodiments, the interior or exterior of waveguide 106 is coated with another metal, e.g., gold.
It should be appreciated that the ratio of width to height can be adjusted to balance electrical performance with mechanical conformability of the waveguide. A “fat” shape closer to a circle where parallel opposing sides 310a and 310b are short relative to the overall dimensions (e.g., where the height approaches the width) is easier to bend but has narrower bandwidth and can have frequency response issues due to propagation mode effects. A “thin” shape where parallel opposing sides 310a and 310b are long relative to the overall dimensions (e.g., where the width is at least three times the height) is difficult to bend without distorting or collapsing. In accordance with various embodiments, the width to height ratio of the waveguide is between 1.5/1 and 2.0/1.
It should be appreciated that the thickness 460 of waveguide 400 is a factor in designing an appropriate waveguide 400. For instance, if the walls of waveguide 400 are too thin, waveguide 400 may deform easily and may not be mechanically stable. If the walls of waveguide 400 are too thick, waveguide 400 may be difficult to bend to shape. In some embodiments, the wall thickness 460 is between 0.20 mm (0.008 inch) to 0.50 mm (0.020 inch). In some embodiments, the ratio of outer height 430 to a thickness 460 of waveguide 400 is between 10/1 and 20/1.
In some embodiments, outer width 410 is between 2.5 mm (0.10 inch) and 5.0 mm (0.20 inch) and outer height 430 is between 1.0 mm (0.040 inch) and 2.5 mm (0.10 inch), such that the wall thickness 460 of waveguide 400 is between 0.20 mm (0.008 inch) to 0.50 mm (0.020 inch). In some embodiments, semicircular radius 450 is between 0.50 mm (0.020 inch) and 1.0 mm (0.040 inch). In an example embodiment, outer width 410 is 3.51 mm (0.138 inch), inner width 420 is 2.97 mm (0.117 inch), outer height 430 is 1.98 mm (0.078 inch), inner height 440 is 1.45 mm (0.057 inch), and semicircular radius 450 is 0.74 mm (0.029 inch), such that the wall thickness 460 of waveguide 400 is 0.27 mm (0.011 inch).
In some embodiments, an obround waveguide is coupled to an interface having a cross section other than an obround cross section. For example, an obround waveguide may be coupled to a waveguide or waveguide interface having a rectangular cross section. In such embodiments, a transition from an obround cross section to a rectangular cross section may be used. In some embodiments, such a transition can be machined or manufactured using electrical discharge machining (EDM).
Tool 500 includes grooves 510, 512, and 514 formed in the exterior surface of tool 500 configured for allowing the bending an obround waveguide across different directions. For example, groove 514 is a narrow groove, relative to grooves 510 and 512, for receiving a curved end of an obround waveguide, and bending over the width of the obround waveguide (e.g., a bend in the H direction). Groove 512 is a wide groove, relative to grooves 510 and 514, for receiving a flat side of an obround waveguide, and bending over the height of the obround waveguide (e.g., a bend in the E direction). Groove 510 is an angled groove for receiving an obround waveguide at an angle (e.g., forty five degrees), and bending the obround waveguide according to the angle. While groove 510 as illustrated includes an angle of forty-five degrees, it should be appreciated that groove 510 may include any angle between zero and ninety degrees.
Tool 500 has a radius 520, where radius 520 defines the radius of a bend in an obround waveguide. It should be appreciated that tool 500 can have any radius 520. For instance, a set of tools 500 may include multiple tools 500, each individual tool having the same grooves (e.g., grooves 510, 512, and 514) while having different radius 520 measurements. This would allow a person manually conforming an obround waveguide with flexibility to be able to bend the obround waveguide according to the particular use situation.
To manually conform a waveguide, a user selects a tool 500 having a desired radius 520. For example, the user would select a tool 500 according to the spacing requirements for placing a conformed waveguide. To use tool 500, a person places an obround waveguide into a selected groove and bends the obround waveguide according to the groove. The radius of the bend of the obround waveguide depends on radius 520 of tool 500.
In some embodiments, system 600 includes a series of sets of metal rollers 610, wherein each successive set of metal rollers 610 has a smaller separation distance. As a hollow component 620 passes through the successive set of metal rollers 610, the thickness of hollow component 620 is reduced. In some embodiments, prior to passing through a set of metal rollers 610, hollow component 620 is a cylindrical hollow component having a cylindrical cross section. In some embodiments, the final set of rollers has a separation distance equal to the outer height 430 of
At procedure 720, the cylindrical hollow component is passed through at least one set of metal rollers for forming the cylindrical hollow component into a conformable waveguide having an obround cross section. The obround cross section is defined as having parallel opposing sides connected by two rounded opposing ends, wherein the parallel opposing sides are separated by a first distance, wherein vertices of the two rounded opposing ends are separated by a second distance, wherein the second distance is greater than the first distance.
In one embodiment, as shown at procedure 730, the cylindrical hollow component is passed through a series of sets of metal rollers, wherein each successive set of metal rollers has a smaller separation distance, and where a final set of rollers has a separation distance equal to the first distance plus a wall thickness of the conformable waveguide.
In one embodiment, a ratio of the second distance to the first distance is between 1.5/1 and 2/1. In one embodiment, the two rounded opposing ends have semicircular cross sections. In another embodiment, the two rounded opposing ends have semielliptical cross sections. In another embodiment, the two rounded opposing ends have semioval cross sections.
What has been described above includes examples of the subject disclosure. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the subject matter, but it is to be appreciated that many further combinations and permutations of the subject disclosure are possible. Accordingly, the claimed subject matter is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.
In particular and in regard to the various functions performed by the above described components, systems, methods, and the like, the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., a functional equivalent), even though not structurally equivalent to the disclosed structure, which performs the function in the herein illustrated examples of the claimed subject matter.
The aforementioned systems and components have been described with respect to interaction between several components. It can be appreciated that such systems and components can include those components or specified sub-components, some of the specified components or sub-components, and/or additional components, and according to various permutations and combinations of the foregoing. Sub-components can also be implemented as components communicatively coupled to other components rather than included within parent components (hierarchical). Additionally, it should be noted that one or more components may be combined into a single component providing aggregate functionality or divided into several separate sub-components. Any components described herein may also interact with one or more other components not specifically described herein.
Thus, the embodiments and examples set forth herein were presented in order to best explain various selected embodiments of the present invention and its particular application and to thereby enable those skilled in the art to make and use embodiments of the invention. However, those skilled in the art will recognize that the foregoing description and examples have been presented for the purposes of illustration and example only. The description as set forth is not intended to be exhaustive or to limit the embodiments of the invention to the precise form disclosed.
