Patent Description:
It is well known in the art of spacecraft antennas to use corrugated antenna components such as corrugated feed horns. In order to significantly improve the antenna electrical RF (Radio Frequency) performance (by reducing the RF losses), such corrugated horns <NUM>, <NUM>', as schematically illustrated in <FIG>, typically include a plurality of corrugations <NUM> formed with respective ridges <NUM> define annular grooved channels adjacent one another. As the dimensions (depth and width) of each one of these ridges <NUM> need to be relatively accurate to ensure the RF electrical performance of the horn, each ridge <NUM> need to be machined using precise CNC (computer numerical control) machining. For horn <NUM> having a relatively small flare angle F, as illustrated in <FIG>, the machining of the ridges <NUM> from the main structure <NUM> is typically limited to ridges <NUM> being generally oriented perpendicular (see dotted line <NUM>) to the axis <NUM> of the horn <NUM>. Also, in few occasions where the flare angle F' of the conical horn structure <NUM>' is wide enough (usually more than <NUM> degrees relative to the horn axis <NUM>), as shown in <FIG>), the absence of physical obstructions make it possible to accurately machine the all ridges <NUM>, via the horn aperture <NUM>, with an orientation perpendicular to the conical structure <NUM>' of the horn <NUM>'.

Corrugated horns with machined corrugations typically suffer from having many drawbacks, especially in aerospace applications where low mass, extreme environmental physical constraints, and high cost, etc. are non-negligible aspects to be considered. For example, CNC machining is time consuming and expensive. Structural integrity of the horns (mainly with low flare angles) requires additional external ribs for bracket attachments or relatively thick walls (for structural integrity), which is non-desirable additional mass.

Similar considerations are also applicable to other corrugated antenna components, such as waveguides, etc..

<CIT>, with publication no. <CIT>, discloses a corrugated feed horn for a reflector antenna having its corrugations formed by a series of grooves having a common depth and in which there are at least two different groups of grooves with different shapes and which are interspersed with each other. <NPL> discoses a method of 3D printing of corrugated horns.

Accordingly, there is a need for an improved corrugated component for use in antennas on board of spacecrafts and the like, and a method of its manufacture.

It is therefore a general object of the present invention to provide an improved corrugated component to obviate the above-mentioned problems, and a method of its manufacture.

An advantage of the present invention is that the single-piece corrugated antenna component can be manufactured by any applicable additive manufacturing technology, or 3D printing. This manufacturing process enables the manufacturing of several components /horns at the same time, as well as the simultaneous inclusion of the ribs and/or mechanical brackets, when applicable. Other parts of the antenna could also be manufactured out of the same single-piece, such at the base/input of the horn towards the rest of the antenna feed. All the above reducing the manufacturing time and cost, as well as up to about <NUM>% of the overall mass of each horn.

Another advantage of the present invention is that the single-piece corrugated component can be manufactured from one way (as from base to aperture for a horn) or the other (as from aperture to base for a horn), and the corrugations could be angled in either direction relative to the component /horn main axis (i.e. toward the aperture or the base for a horn).

A further advantage of the present invention is that the structural performance of the corrugated component is optimal, i.e. the 3D printed supports are thickness, profile, and position tuned to minimize stress concentrations, eliminate internal parts, bolted and bonded interfaces; and meet thermoelastic (flexible), stiffness (eigen and buckling), and strength (static and dynamic) requirements for the space (LEO, MEO, and GEO - Low, Medium and Geostationary Earth Orbit) and launch environments.

Still another advantage of the present invention is that the time to design and analyze the horn is significantly reduced from the traditional design. This advantage also applies to adaptability of the design to variation of customer requirements including for example interface locations and RF requirements.

Yet another advantage of the present invention is that the structural supports of the horn occupy less volume than traditional design, thus permitting more payload to be mounted on the same spacecraft.

Yet a further advantage of the present invention is that the natural shape and orientation of the component corrugations (or the respective ridges), between a cone plus or minus ten (<NUM>) degrees and a cone plus or minus sixty (<NUM>) degrees with respect to the component axis, as required by the RF design, and not typically perpendicular to the wall of the component, provide a bellows type of structure, which is inheritably flexible and optimal to withstand on-orbit thermoelastic deformations. To complement the above-mentioned structural optimization, the rigidity and thickness of the component wall is locally tunable to provide the stiffness and strength needed to also withstand the launch environment, without compromising the flexibility advantage of the natural bellows shape.

Still a further advantage of the present invention is that the corrugated component or horn can be printed with the rest of, or at least a portion of the feedchain (such as a circular waveguide to rectangular waveguide transition, an orthomode transducer (OMT), a diplexer, a filter, a polarizer, a coupler, or any other feeding network component, etc.) in one single piece which significantly reduces the assembly time and overall mass of the feedchain, which proves especially efficient in space applications.

According to an aspect of the present invention there is provided a single-piece corrugated component of an antenna comprising:.

characterized in that the side surfaces of each said frustopyramidal ridge extending inwardly and perpendicularly from an inner surface of the main body at an angle relative to the body axis varying between about ten and about sixty degrees in a direction either toward the first end or the second end.

In one embodiment, the ridge of each said corrugation extends inwardly in a direction toward the first end.

In one embodiment, the ridge of each said corrugation extends inwardly in a direction toward the second end.

In one embodiment, the first end is a base and the second end is an aperture, the main body flaring out from the base toward the aperture at a flare angle being less than <NUM> degrees (<<NUM>°) relative to the body axis.

In one embodiment, an attachment bracket extends outwardly from the main body.

In one embodiment, the main body has a generally hollowed frustoconical shape, and conveniently a generally hollowed cylindrical shape or a generally hollowed frustopyramidal shape, or a generally hollowed prismatic shape.

In one embodiment, the main body has a first section having a generally hollowed frustoconical shape and a second section having a generally hollowed frustopyramidal shape.

In one embodiment, the body axis is generally rectilinear, and conveniently, the first end and the second end are generally parallel to one another.

In one embodiment, the body axis is generally curvilinear.

According to another aspect of the present invention there is provided an antenna section comprising the single-piece corrugated component as detailed hereinabove and at least one of a circular waveguide to rectangular waveguide transition, an orthomode transducer, a diplexer, a filter, a polarizer, a coupler, and another feeding network component adjacent the first end of the main body and being part of the single-piece.

According to another aspect of the present invention there is provided a method for manufacturing a single-piece corrugated component or an antenna section as detailed hereinabove comprising the step of printing said corrugated single-piece using an additive manufacturing (or 3D printing) technology.

Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings.

Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, in which similar references used in different Figures denote similar components, wherein:.

With reference to the annexed drawings the preferred embodiment of the present invention will be herein described for indicative purpose and by no means as of limitation.

Referring to <FIG>, there is shown a single-piece corrugated antenna feed component, more specifically a feed horn being illustrated, in accordance with an embodiment <NUM> of the present invention, typically for use in antennas onboard of spacecraft (not shown) or the like to transmit (Tx) and/or receive (Rx) an RF (radio-frequency) electromagnetic signal of a predetermined signal frequency band.

The single-piece corrugated horn <NUM> is preferably manufactured using a 3D (three dimensional) printer and includes a main body <NUM> having a generally hollowed frustopyramidal (frustoconical for a circular component) shape which defines a body axis <NUM>. The main body <NUM> extends from a first end <NUM> toward a second end <NUM>. As better seen in <FIG>, the main body <NUM> includes a plurality of corrugations <NUM> centered about the body axis <NUM>, respectively, and protruding inwardly from an inner surface <NUM> of the main body <NUM>. Each corrugation <NUM> is a frustopyramidal (frustoconical for a circular component) ridge <NUM> with side surfaces thereof that extends inwardly of the main body <NUM> at an angle A relative to the body axis <NUM> typically varying between about ten (<NUM>) and about sixty (<NUM>) degrees, and preferably about forty-five (<NUM>) degrees, and on either direction i.e. toward the first end <NUM> or toward the second end <NUM>, as to provide for a flexible and optimal bellows type of structure. Typically, an attachment bracket <NUM> could extend outwardly from the main body <NUM> to allow for the securing of the horn <NUM> to an adjacent supporting structure (not shown).

The term 'frustopyramidal' (or 'frustoprismatic'), in the present description, includes the term 'frustoconical' that is a specific case in which the truncated pyramid has an infinite number of side surfaces to form a truncated cone.

In the case of the antenna component being a horn, as illustrated in <FIG>, the main body <NUM> typically flares out from the first end or base <NUM> toward the second end or aperture <NUM>, at a flare angle F being less than <NUM> degrees (<<NUM>°), and typically varying between about <NUM> degrees to about <NUM> degrees (<NUM>°-<NUM>°) relative to the body or horn axis <NUM>. Although the flare angle F is shown as being constant (rectilinear tapering), it could be variable for different sections of the main body <NUM> and non-uniform along the body axis <NUM> (as illustrated in <FIG>).

The term 'frustopyramidal', in the present description, also includes the term 'prismatic' that is another specific case in which the truncated pyramid has essentially a zero-degree (<NUM>°) flare angle F, such that the side surfaces of the truncated pyramid are essentially parallel to the body axis <NUM>. Similarly, when the 'prismatic', in the present description, includes the term 'cylindrical' that is a specific case in which the prism has an infinite number of side surfaces to form a cylinder.

In the embodiment <NUM> shown in <FIG>, each corrugation <NUM> or ridge <NUM> tapers, or is oriented in the direction towards the base <NUM>.

Alternatively, the embodiment <NUM>' illustrated in <FIG> has the corrugations <NUM> or ridges <NUM> tapering in the direction of the aperture <NUM>.

In both embodiments <NUM>, <NUM>', but more specifically the embodiment of <FIG>, most of each ridge <NUM> is oriented in such a way that its inward virtual extension <NUM>, shown in stippled lines, crosses the horn axis <NUM> and intersects the main body <NUM> of the horn <NUM>. This axis-crossing characteristic specifically prevents the horn <NUM> from being easily machined with conventional high precision CNC machines at reasonable cost. Only the first few corrugations <NUM>' or ridges <NUM>' adjacent the aperture <NUM> in the embodiment of <FIG> do not have this characteristic.

For structural integrity of the component/horn <NUM>, or other considerations, some sections of the main body <NUM> can include ribs <NUM> or the like.

Without departing from the scope of the present invention, one skilled in the art would readily understand that multiple shapes of the main body <NUM> could be considered, as well as different combination(s) thereof. As non-limiting examples, <FIG> respectively show other embodiments <NUM>, <NUM> of single-piece corrugated feed horn components having main bodies <NUM>, <NUM> of rectangular and square frustoprismatic (the term 'frusto' referring to a truncated taper or flare) shapes, with corresponding rectangular and square frustopyramidal ridges <NUM>, <NUM>.

Similarly, <FIG> shows another embodiment <NUM> of a single-piece corrugated feed horn component having a main body <NUM> of a hexagonal prismatic shape, with hexagonal frustopyramidal ridges <NUM>.

<FIG> shows another embodiment <NUM> of a single-piece corrugated feed horn component having first 512a and second 512b sections of the main body <NUM> of circular frustoconical and hexagonal frustoprismatic shapes, respectively, with corresponding circular frustoconical (not shown) and hexagonal frustopyramidal 524b ridges.

Alternatively, <FIG> respectively show other embodiments <NUM>, <NUM> of single-piece corrugated waveguide components having main bodies <NUM>, <NUM> of cylindrical shapes (or circular frustoconical shapes with essentially zero degree (<NUM>°) of flare angle F), with circular frustoconical ridges <NUM>, <NUM> along rectilinear (or straight) and curvilinear (or curved or bent) body axes <NUM>, respectively. Although illustrated here with a circular waveguide component, any component could have a curvilinear body axis <NUM>.

As illustrated in <FIG> and <FIG>, the body axis <NUM> is generally rectilinear (or straight), and as illustrated in <FIG>, the body axis <NUM> is generally curvilinear (or curved or bent). When the body axis <NUM> is rectilinear, the first end <NUM> and the second end <NUM> are generally parallel to one another, although they could not be, if required for the specific needs.

<FIG> shows another embodiment <NUM> of a single-piece corrugated feed horn in which the flare angle (F) is different for different and successive sections <NUM>' of the main body <NUM>, or could also be continuously varying within a section <NUM>' (as a generally splined circular frustoconical shape of the main body <NUM>). Similarly, although not visible from the figure, the circular frustoconical ridges <NUM> could have different orientations for the different sections <NUM>' of the main body <NUM>.

The present invention also includes a method for manufacturing any one of the above embodiments <NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> comprising the step of printing the corrugated antenna component using an applicable additive manufacturing (or 3D printing) technology. The embodiments <NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are typically manufactured, or printed from the second end or aperture <NUM> toward the first end or base <NUM>, or the other way around, from the base <NUM> toward the aperture <NUM>, respectively.

Also, one skilled in the art would readily realize that, without departing from the scope of the present invention, the method of 3D printing, or additive manufacturing, of the horn <NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> allows for other section(s) of the antenna feed, such as a circular waveguide to rectangular waveguide transition, an orthomode transducer, a diplexer, a filter, a polarizer, a coupler, or any other feeding network component (as waveguides of <FIG>), etc., to be simultaneously manufactured in the same piece, typically adjacent the first end or base <NUM>.

Claim 1:
A single-piece corrugated component (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) of an antenna comprising:
- a main body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) having a generally hollowed frustopyramidal or frustoconical shape defining a body axis (<NUM>), the main body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) extending from a first end (<NUM>) to a second end (<NUM>), the main body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) including a plurality of corrugations (<NUM>, <NUM>') centered about the body axis (<NUM>), respectively, each said corrugation (<NUM>, <NUM>') having a frustopyramidal ridge adjacent a respective channel and defining side surfaces thereof;
- wherein a plurality of the frustopyramidal ridges (<NUM>, <NUM>, <NUM>, <NUM>, 524b, <NUM>, <NUM>, <NUM>) having a respective inward virtual extension (<NUM>) thereof crossing the body axis (<NUM>) and intersecting the main body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
characterized in that the side surfaces of each said frustopyramidal ridge (<NUM>, <NUM>', <NUM>, <NUM>, <NUM>, 524b, <NUM>, <NUM>, <NUM>) extending inwardly and perpendicularly from an inner surface (<NUM>) of the main body at an angle (A) relative to the body axis (<NUM>) varying between about ten and about sixty degrees in a direction either toward the first end (<NUM>) or the second end (<NUM>).