Antenna structure

Abstract

The present invention relates to an antenna structure comprising a waveguide, with the waveguide comprising a guide element for guiding waves and with a termination structure protruding away from the guide element being provided adjacent to the latter.

Description

[0001] Antenna structure

[0002] The present invention relates to an antenna structure, in particular for use in the high-frequency range, comprising a waveguide, wherein the waveguide has a guide element for guiding waves.

[0003] Such an antenna structure serves, for example, to guide and / or emit electromagnetic waves. Electromagnetic waves, especially radio-frequency signals, can propagate either in a space or in waveguides. Such waveguides provide conductive structures that encompass a spatial area and thus form a spatial path or channel for guiding the electromagnetic waves or radio-frequency signals within it, or for manipulating them in space or the frequency range, or for emitting them in these areas.

[0004] In many radar sensor applications, a "360-degree view" of the antenna structure is a great advantage. Implementing this technically generally proves rather difficult.

[0005] Figure 14 shows a cross-sectional view of a conventional waveguide slot antenna, which comprises a waveguide 10 having one or more slots S on its upper wall. A denotes the main radiation area of ​​the waveguide slot antenna 10. As can be seen from the figure, not the entire space around the waveguide is covered or supplied, but only a partial circle, shown schematically here. In the area not covered by the partial circle, e.g., next to and below the antenna, the antenna is "blind."

[0006] To solve this problem, it would be conceivable to arrange another waveguide slot antenna below the illustrated slotted waveguide antenna. From a conventional perspective, this would allow the space to be divided into several sectors, which would be illuminated independently or partially overlappingly by several antennas.

[0007] This concept is accompanied by a very irregular gain curve due to the spatial arrangement of the elements (array structure) and the spatial distance of the waveguide slot antenna (usually more than lambda 1 / 2).

[0008] Other solutions, for example, use slot antennas on circular waveguides, which provide all-round illumination of the room. However, integrating multiple such antennas into a MIMO radar system proves difficult due to the design, as the antennas are constantly in each other's way, as all sides of the circular waveguide must be slotted.

[0009] The present invention is therefore based on the object of developing an antenna structure of the type mentioned at the outset in such a way that uniform all-round coverage of the room or all-round radiation into the room is possible.

[0010] This object is achieved by an antenna structure having the features of claim 1. According to this, a terminal structure extending away from the guide element, i.e., protruding from the waveguide slot antenna, is provided adjacent to the guide element. This terminal structure can be wing-shaped, for example, or designed in another manner.

[0011] Surprisingly, it has been shown that such a structure achieves a very uniform all-round detection or radiation area. The terminating structure influences the radiated or received electromagnetic waves in such a way that a larger area is covered compared to the area shown in Figure 14, so that blind spots can be reduced or completely eliminated, depending on the arrangement of the waveguide(s) or the radiating slots, etc., and the terminating structures.

[0012] The guide element can be a dielectric waveguide, which preferably has one or more electrically conductive strips (dielectric antenna: here the conductor and non-conductor are interchanged).

[0013] It is particularly preferred if the guide element is a waveguide comprising a guide channel whose inner surfaces are electrically conductive at least in some regions, wherein the guide channel has a first wall with one or more openings. A preferred embodiment thus consists of a waveguide provided with radiating slots on at least one side, the at least one non-radiating side of which is terminated by a termination structure, i.e., a "surface termination structure," of primarily triangular cross-section.

[0014] The guide element is preferably elongated. It can be straight or curved. The same applies to the end structure.

[0015] The guide element may have a longitudinal axis, wherein the closure structure extends in the direction of the longitudinal axis and preferably parallel to the longitudinal axis of the guide element.

[0016] The terminating structure can have a different cross-sectional shape than the guide element. For example, it is conceivable for the guide element, e.g., the waveguide, to have a rectangular cross-section, while the terminating structure can have a triangular or rounded cross-section. It is conceivable for the terminating structure to be designed as a compact body, e.g., a body without a cavity, or as a hollow body.

[0017] In one embodiment, the end structure has a polygonal cross-section, preferably triangular, or round. For example, a partially circular, triangular, polygonal, etc. structure is possible.

[0018] In a further embodiment, the guide channel has a second wall, wherein the second wall is a non-radiating side of the waveguide and wherein the termination structure extends from the second wall.

[0019] In the context of this document, the terms "perforation," "slots," etc., can refer to openings that improve the accessibility of process media, such as ink for coating. These are non-radiating openings. Walls with such openings are also referred to as non-radiating walls or non-radiating sides, etc.

[0020] The terms "perforation," "slots," etc., also include wave-radiating openings. These do not intersect the current density distribution on the inner walls of the waveguide perpendicular to its flow direction. In the context of the present disclosure, these are also referred to as radiating perforations, radiating slots, etc. The walls with such openings are also referred to as radiating walls or radiating sides, etc.

[0021] In detail, this is achieved, among other things, by ensuring that these non-radiating openings are significantly smaller than half a wavelength and are oriented along the direction of current flow. For example, on the narrow sides, they are "top to bottom." The non-radiating openings are primarily very small (small rectangular openings), where the term "small" refers to small compared to the wavelength: specifically, smaller than one wavelength.

[0022] Furthermore, the guide channel can be provided with a third wall having one or more openings, wherein the third wall is preferably arranged opposite the first wall. The third wall can thus also be, for example, a radiating wall.

[0023] Furthermore, the guide channel can have a fourth wall, to which a further closing structure is connected, wherein it is preferably provided that the fourth wall is arranged opposite the second wall.

[0024] Preferably, this fourth wall is a non-radiating side of the waveguide.

[0025] The closure structure preferably extends over more than half the length of the guide element, preferably over more than % of the length of the guide element and particularly preferably over the entire length of the guide element.

[0026] It is particularly advantageous if the closing structure is located in at least one area where the guide element has radiating openings in its wall, but preferably over the area of ​​maximum radiation of the guide element or even over the entire radiating area of ​​the guide element, wherein the radiating area of ​​the guide element is characterized in that in this area radiating openings are present in at least one of the walls of the guide element.

[0027] The closing structure can have a flat side that abuts one side of the guide element, wherein it is preferably provided that the two adjacent sides have the same height and / or width. It is also conceivable for the closing structure to have a side, preferably an edge, that faces away from the side of the guide element from which the closing structure extends. For example, it is conceivable for the closing structure to be tapered away from the guide element, preferably tapered to a point.

[0028] Preferably, the final structure is a three-sided prism.

[0029] The termination structure can be formed as a single piece with the waveguide. It is also conceivable that the termination structure and the waveguide consist of separate parts that are then joined together.

[0030] Furthermore, it can be provided that the side of the terminating structure facing away from the waveguide, preferably with its edge being straight or corrugated or having one or more recesses, preferably has a serrated structure. The terminating structure can have this edge structure over its entire length or only in a partial area. In its longitudinal orientation, the terminating structure can be serrated or corrugated along the edge, for example.

[0031] The antenna structure can comprise exactly one waveguide or several waveguides arranged side by side and / or one above the other. The antenna structure can thus comprise an array of waveguides.

[0032] For example, pairs of single-sided slotted waveguides arranged back-to-back are conceivable, so that one waveguide radiates upwards, etc., while the other waveguide radiates in the opposite direction. The two waveguides can be fed via a power splitter, which has the advantage of allowing different radiation patterns to be achieved at the front and rear, or at opposite sides of the antenna structure. It is conceivable for each waveguide, particularly the waveguide itself, to be provided with one or more termination structures. It is also possible for multiple waveguides to share a common termination structure.

[0033] In a further embodiment, the guide channel is filled with air or with a dielectric, in particular with ceramic.

[0034] The waveguide can be a hollow waveguide or an antenna, in particular a horn antenna, or a filter or a resonator or a coupler or another passive RF component. The antenna structure can comprise one or more of the aforementioned components, which are preferably implemented in a common component.

[0035] The guide element can be terminated at one end, for example by a short circuit or by an open circuit (so that a standing wave can be generated, this is a resonant antenna).

[0036] Preferably, the antenna structure is a radar sensor or part of it.

[0037] The antenna structure can be flat or conformal on a curved surface shape.

[0038] It is conceivable that the antenna structure has slots or other openings as radiating elements on one or two or more than two sides, preferably on two opposite sides, such as at the top and / or bottom.

[0039] The guide element can be designed in cross-section such that its height is preferably less than half the width

[0040] The guide element can be rectangular, polygonal, round, rounded, elliptical, or otherwise shaped in cross-section. It can contain one or more pairs of single-sided slotted waveguides, positioned back-to-back, and a power splitter for feeding the waveguides.

[0041] The present invention further relates to a method for producing an antenna structure according to one of claims 1 to 24, wherein the guide element is produced partially or completely by means of an additive process, in particular 3D printing, SLS printing, metal printing, SLA 3D printing, machining or by means of plastic injection molding.

[0042] The antenna structure and / or its waveguide can be manufactured monolithically or from several parts.

[0043] In a further embodiment of the invention, the method comprises immersing the waveguide one or more times in an immersion bath containing a dispersion, in particular an ultrasonic bath, wherein the dispersion comprises metal-containing particles, in particular gold and / or silver and / or copper particles.

[0044] Furthermore, it can be provided that, before the coating, one or more slots penetrating the walls of the base body forming the inner surfaces of the base body are introduced in order to promote the circulation of the dispersion in the cavity or in the region of the inner surfaces of the waveguide.

[0045] High-frequency components according to the present invention can comprise 3D-printed or injection-molded plastic base bodies that form the base body of the waveguide. These must be provided with a conductive coating for subsequent functionality.

[0046] Methods considered here include galvanic or electroless coating with metals, as well as chemical coating, in which a chemical reaction occurs between the reagent liquid and the surface of the body to be coated. However, the process known from DE 10 2020 104 038.5 is particularly advantageous. The disclosure content of this patent application is hereby incorporated by reference in its entirety. The necessary electrically conductive coating of the base body is achieved by wetting at least part, preferably the entire surface of the base body of the waveguide with a dispersion containing electrically conductive micro- and / or nanoparticles. The dispersion can be an ink with micro- or nanoparticles. Conceivable nanoparticles are aluminum, silver, gold or copper particles or a mixture thereof. The dispersion orThe ink is matched to the surface energy of the base material used, e.g. plastic, so that sufficient wetting of the surface is promoted.

[0047] After the solvent / water has evaporated, the surface of the substrate is wetted with the ink material, and optional post-treatment, preferably through heat, such as sintering, forms a conductive coating. This process is thus a physical wetting process, in which a conductive coating is formed through post-treatment.

[0048] It should be noted here that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this is a possible interpretation, but can also refer to a plurality of the elements. Likewise, the use of the plural also includes the presence of the element in question in the singular, and conversely, the singular also encompasses several of the elements in question.

[0049] It is further noted that any feature of this disclosure may be combined with any other feature of this disclosure.

[0050] Further details and advantages of the invention are explained in more detail with reference to an embodiment shown in the drawing.

[0051] Shown are: Figure 1: a perspective view of a waveguide slot antenna structure with a waveguide with a one-sided termination structure,

[0052] Figure 2: a view of the arrangement according to Figure 1 in longitudinal section,

[0053] Figure 3: a view of the arrangement according to Figure 1 in cross section,

[0054] Figure 4: a perspective view of a waveguide system with three monolithic waveguides arranged side by side with a termination structure arranged on both sides,

[0055] Figure 5: a view of the arrangement according to Figure 4 in longitudinal section,

[0056] Figure 6: a view of the arrangement according to Figure 4 in cross section,

[0057] Figure 7: a perspective view of a waveguide slot antenna structure with a waveguide with a termination structure arranged on both sides.

[0058] Figure 8: a view of the arrangement according to Figure 7 in cross section,

[0059] Figure 9: a perspective view of a waveguide slot antenna structure with three adjacently arranged individual waveguides with a termination structure arranged on both sides with openings in the termination structure,

[0060] Figure 10: a view of the arrangement according to Figure 9 in longitudinal section,

[0061] Figure 11 : a view of the arrangement according to Figure 9 in cross section,

[0062] Figure 12: a schematic view of the radiation or reception area of ​​an antenna structure according to the invention in the case of a waveguide with a termination structure, Figure 13: a schematic view of the radiation or reception area of ​​a waveguide slot antenna structure according to the invention in the case of two waveguides arranged back to back, each with a termination structure, and

[0063] Figure 14: a schematic view of the radiation or reception area of ​​a waveguide slot antenna structure in a waveguide without a termination structure.

[0064] In the figures, identical or functionally identical elements are provided with identical reference symbols.

[0065] Figure 1 shows, with reference numeral 10, a waveguide which, as can be seen from Figure 2, has a first wall 1 and a third wall 3, each provided with slots S. The two walls 1, 3 are thus radiating sides of the waveguide 10.

[0066] The side walls of the waveguide 10 are perpendicular to the walls 1, 3, resulting in a rectangular cross-section of the waveguide 10. The side walls 2, 4 are closed, i.e., they do not have any radiating slots. However, they can also have non-radiating slots for processing.

[0067] These sides of the waveguide are therefore non-radiating. Of the side walls, only side wall 2 is visible in Figure 1.

[0068] A termination structure 20 adjoins the side wall 4 of the waveguide 10, which is opposite the side wall 2. The termination structure 20 has a triangular cross-section, with the legs 21, 22 of the triangle being much longer than its base 23, resulting in a tapered triangle. The apex S points away from the waveguide 10, as shown in Figure 1.

[0069] The length of the base 23 corresponds to the height of the waveguide 10, so that the termination structure does not protrude beyond the waveguide either at the top or bottom. The triangular angle of the tip is preferably < 45°, particularly preferably < 20°.

[0070] Preferably the triangle is isosceles.

[0071] Figure 3 shows that the closure structure is compact, ie not hollow.

[0072] The waveguide 10 and the termination structure 20 are two-part, ie they do not consist of one and the same part.

[0073] Figure 4 shows an embodiment in which three waveguides 10 are arranged next to one another, as can be seen in particular from the sectional views of Figures 5 and 6.

[0074] Each of the waveguides 10 has slots at the top and bottom, ie the antenna structure radiates from both sides.

[0075] The three waveguides are monolithic, i.e. they consist of a common part.

[0076] The two outer waveguides are each provided with a termination structure 20 on their respective lateral outer walls. The termination structures arranged on both sides are arranged mirror-symmetrically relative to the center plane of the antenna structure.

[0077] Figures 7 and 8 show, in perspective and sectional view, an embodiment according to Figure 1, but with the difference that a termination element 20 is connected to each of the side walls of the waveguide slot antenna structure. The termination elements point in different, opposite directions at their tips. Figures 9 to 11 show a further embodiment with three adjacent waveguides 10 consisting of individual elements. They are still monolithically manufactured, but hollow and have perforations.

[0078] Deviating from the above embodiments, in the embodiment of Figures 9 to 11, the terminating structures 20 have a cavity and openings 30. These openings are preferably non-radiating openings.

[0079] These are located at the top and bottom of the walls of the end element in the area of ​​the cavity.

[0080] In addition, openings are also provided in the end element in the area where there is no cavity.

[0081] Figure 12 shows the radiation area A of a waveguide slot antenna structure according to the invention comprising a slotted (slots S) waveguide 10 and the termination structure 20.

[0082] In comparison, Figure 14 shows the radiation area A of a waveguide slot antenna structure not according to the invention, comprising the same waveguide 10 as in Figure 12, but without a terminating structure. It is clearly evident from a comparison of the figures that, under identical operating conditions, the radiation area of ​​the antenna structure is significantly increased simply by the presence of the terminating structure 20 and, in particular, also includes an area adjacent to the waveguide 10.

[0083] Figure 13 illustrates that a very uniform "all-round" radiation area A is achieved in the exemplary embodiment in which two waveguides 10, each provided with slots S on their free outer sides, are arranged back to back, with the waveguide being provided with a termination element 20 on its free side. Each of the termination elements 20 has a height corresponding to the height of the two waveguides arranged one above the other. In principle, a single waveguide radiating from the top and bottom, which is provided with a termination element 20 on each side, can also be used to achieve this result.

[0084] Preferred, non-limiting embodiments of the invention are described below.

[0085] A type of "surface termination structure" is used, primarily angular in cross-section and the non-radiating waveguide side is used.

[0086] Other cross-sections of the final structure are also conceivable, e.g.: round, polygonal.

[0087] The final structure can be jagged or wavy along the edge or even straight.

[0088] A particularly flat waveguide is advantageous, preferably with a height less than half the width, e.g.: Width: 3 to 4 mm & Height: 1 mm at 60-90 GHz

[0089] Preferably, the waveguide is slotted on both sides (on one side group). The side group is either both wide sides or both narrow sides

[0090] The plan is for a waveguide provided with radiating slots on at least one side, at least one non-radiating side of which is terminated with a "surface termination structure", primarily of triangular cross-section.

[0091] The cross-sectional shape of the waveguide can be rectangular but also round or generally elliptical or otherwise.

[0092] It is conceivable to integrate several such antennas into a structure with a common surface. An array of such antennas is preferred. Such an array can be used, for example, for MIMO (multiple-input multiple-output) systems (a system concept from radar technology).

[0093] Pairs of single-sided slotted (very narrow or low-height) waveguides placed back to back and fed via a power splitter are also conceivable, with the advantage that different radiation characteristics are present at the front and rear or on both sides.

[0094] The waveguide arrangement can be flat, but can also be conformally mapped onto curved surface shapes.

[0095] Instead of air, the waveguide can also be filled with dielectric material, e.g. ceramic.

[0096] Instead of a conductive waveguide with slots for radiation, a dielectric waveguide with conductive strips is also conceivable (dielectric antenna: here the conductor and non-conductor are swapped).

[0097] The slotted waveguide can have a base body with non-radiating slots for electroplating. In this case, additional slots or similar are provided to ensure particularly good penetration of the material coating the inside of the base body into the interior of the waveguide base body.

[0098] The waveguide can be manufactured as a 3D printed part (metal & / or plastic) with subsequent coating.

[0099] The waveguide can be monolithic or made of several parts (i.e. also manufactured conventionally) or as an injection-molded part or manufactured conventionally.

[0100] An advantageous field of application of the waveguide arrangement according to the invention is the “all-round view”, ie the 360° detection of waves from the environment or the radiation of waves into the environment.

Claims

Claims: An antenna structure comprising a waveguide, wherein the waveguide has a guide element for guiding waves, characterized in that a termination structure projecting away from the guide element is provided adjacent to it. Antenna structure according to claim 1, characterized in that the guide element is a dielectric waveguide, preferably comprising one or more electrically conductive strips. Antenna structure according to claim 1, characterized in that the guide element is a waveguide comprising a guide channel, the inner surfaces of which are at least partially electrically conductive, wherein the guide channel has a first wall having one or more radiating perforations. Antenna structure according to claim 3, characterized in that the guide channel has one or more walls, and that the openings are present in one, several, or all of the walls. Antenna structure according to any one of the preceding claims, characterized in that the guide element has a longitudinal axis and that the termination structure extends in the direction of the longitudinal axis and preferably parallel to the longitudinal axis of the guide element. Antenna structure according to any one of the preceding claims, characterized in that the termination structure has a different cross-sectional shape than the guide element and / or that the termination structure is designed as a solid or hollow body. Antenna structure according to any one of the preceding claims, characterized in that the termination structure has a polygonal, preferably triangular, or round cross-section and / or that the guide element is terminated at one end.Antenna structure according to any one of claims 3 to 7, characterized in that the guide channel has a second wall, wherein the second wall is a non-radiating side of the waveguide and wherein the termination structure extends from the second wall. Antenna structure according to any one of claims 3 to 8, characterized in that the guide channel has a third wall which has no, one or more openings, wherein the third wall is preferably arranged opposite the first wall. Antenna structure according to any one of claims 3 to 9, characterized in that the guide channel has a fourth wall which has a further termination structure, wherein it is preferably provided that the fourth wall is arranged opposite the second wall. Antenna structure according to claim 10, characterized in that the fourth wall is a non-radiating side of the waveguide.An antenna structure according to one of the preceding claims, characterized in that the termination structure is located in at least one region where the guide element has radiating perforations in its wall, preferably, however, over the region of maximum radiation of the guide element or even over the entire radiating region of the guide element, wherein the radiating region of the guide element is characterized in that radiating perforations are present in at least one of the walls of the guide element in this region. An antenna structure according to one of the preceding claims, characterized in that the termination structure extends over more than half the length of the guide element, preferably over more than % of the length of the guide element, and particularly preferably over the entire length of the guide element.Antenna structure according to one of the preceding claims, characterized in that the termination structure has a side which abuts a side of the guide element, preferably having the same height and / or width. Antenna structure according to one of the preceding claims, characterized in that the termination structure has a side, preferably An antenna structure according to claim 15, characterized in that the side, preferably the edge, is straight or corrugated or has one or more indentations, preferably has a serrated structure and / or is tapered. An antenna structure according to any one of the preceding claims, characterized in that the antenna structure comprises exactly one waveguide or guide element or several waveguides or guide elements and / or antenna structures arranged side by side and / or one above the other. An antenna structure according to any one of claims 3 to 17, characterized in that the guide channel is filled with air or with a dielectric, in particular with ceramic.An antenna structure according to any one of the preceding claims, characterized in that the waveguide is a hollow waveguide or an antenna, in particular a horn antenna, or a filter or a resonator or a coupler or other RF component. An antenna structure according to any one of the preceding claims, characterized in that it is flat or conformally formed on a curved surface. An antenna structure according to any one of the preceding claims, characterized in that the antenna structure has slots or other openings as radiating elements on one or two or more than two sides, preferably on two opposite sides, such as the top and / or bottom. Antenna structure according to one of the preceding claims, characterized in that the guide element has a cross-sectional shape such that its height is preferably less than half its width. Antenna structure according to one of the preceding claims, characterized in that the guide element has a cross-sectional shape that is rectangular, polygonal, round, rounded, elliptical, or otherwise shaped. Antenna structure according to one of the preceding claims, characterized in that it comprises one or more pairs of waveguides slotted on one side, with their backs abutting each other, and a power divider for feeding the waveguides. Method for manufacturing an antenna structure according to one of claims 1 to 24, characterized in that the guide element is manufactured partially or completely by additive manufacturing, in particular by 3D printing, SLS printing, metal printing, SLA 3D printing, machining, or by injection molding.A method according to claim 25, characterized in that the waveguide structure is manufactured monolithically or from several parts. A method according to claim 25 or 26, characterized in that the method comprises immersing the guide element once or several times in an immersion bath containing a dispersion, in particular an ultrasonic bath, wherein the dispersion comprises metal-containing particles, in particular gold and / or silver and / or copper particles. A method according to any one of claims 25 to 27, characterized in that the method comprises the step of electroplating or electroless coating the guide element. Method according to one of the preceding claims, characterized in that, prior to coating, one or more slits or other perforations penetrating the walls of the base body forming the inner surfaces are introduced in order to promote the circulation of the dispersion in the cavity or in the area of ​​the inner surfaces.

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