Antenna element, receiver, transmitter, transceiver, vehicle and method for manufacturing an antenna element

Abstract

Antenna element (100, 200, 300, 400, 500, 600, 900), comprising: - a planar antenna electrode (110) with a main surface (112), wherein the main surface (112) of the antenna electrode (110) has at least one depression (114) and at least one elevation (116), - a substrate (640) on which the antenna electrode (110) is formed, and - a ground electrode (810), namely a ground plane, which is arranged on one side of the substrate (640) opposite the antenna electrode (110), - wherein - the antenna electrode (110) and / or at least its main surface (112) has a three-dimensional surface deformation in a third spatial direction which is orthogonal to two spatial directions lateral to the main surface (112), and - the substrate (640) has a has a sloping edge region, such that on one side of the substrate (640) opposite the antenna electrode (110) there is a surface at least partially surrounded by the substrate (640), i.e.a partially enclosed installation space is available,- wherein the sloping edge area forms inclined or vertical side walls of the installation space partially enclosed by the substrate (640), and- wherein the ground electrode (810) is arranged between- the side of the substrate (640) opposite the antenna electrode (110) and- the installation space which is at least partially enclosed.

Description

Exemplary embodiments relate to an antenna element according to claim 1, a receiver, transmitter or transceiver according to claim 17, a vehicle according to claim 18 and a method for manufacturing an antenna element according to claim 19. Navigation and positioning using GPS (Global Positioning System), GLONASS, Galileo, commonly referred to as GNSS (Global Navigation Satellite System), is a radio service found in almost every modern vehicle. Due to the long distances involved in satellite communication and their resulting low signal strength, the antenna system is typically designed as an active antenna, with the antenna itself combined with a low-noise amplifier (LNA) at its feed point. Beyond functionality requirements, other aspects often need to be considered, such as design constraints and cost-effectiveness. In particular, vehicle design is becoming increasingly important, which means that the available space for antenna integration is becoming fewer and more limited, while the number of radio services is increasing. Reducing complexity is one possible approach to reducing production costs.For example, reducing the number of components in a subsystem can lead to the desired cost reduction. Shark-fin antenna systems are virtually indispensable in modern automobiles. The patch antenna, used for GPS tracking among other things, is an essential component of this system. Typical microstrip antennas (patch antennas) have a planar structure consisting of an element with an arbitrary planar geometry, which is mounted on a substrate over a planar ground plane. These antennas are typically built on planar printed circuit boards. For miniaturization, ceramic substrates with appropriate electromagnetic properties can be used instead. Depending on the feed method, current distributions (modes) can be excited on the surface. Radiation in this type of antenna occurs at the edges of the patch plane. The shape of the antenna surface, the ground plane, and the excited current distribution influence the radiation pattern, polarization, and antenna input impedance. The latter, along with material losses in the substrate and metallization, affects the antenna's efficiency—that is, how much of the fed power is actually radiated.It is desirable to be able to adapt the antenna characteristics as precisely as possible to the application and to optimize the installation space. The publications WO 2013 / 006788 A2 , US 6121932 A , WO 2012 / 165797 A2 and WO 01 / 37366 A1 show different types of known antenna structures. DE 101 38 265 A1 shows an antenna element with detour lines and shielding chambers for additional components between an antenna electrode and a ground electrode designed as a ground plane. DE 699 37 048 T2 shows an antenna element with two structured antenna electrodes on the same side of a substrate, below which is a structured ground electrode. DE 10 2005 041 890 A1 shows an antenna element with an antenna electrode which, in contrast to a ground electrode designed as a ground plane, is structured and whose course differs from the course of the ground plane. GUSTRAU, Frank: High-frequency technology - Fundamentals of mobile communication technology, 2nd edition, Munich: Carl Hanser Verlag, 2013, pp. 15 - 23, eISBN 978-3-446-43399-1 mentions vehicles as an example of high-frequency applications. There is a need to create an improved concept for an antenna element that offers high flexibility for implementing an antenna with the desired antenna characteristics and / or allows for good utilization of the installation space. This need is addressed by the subject matter of the claims. According to the invention, an antenna element is provided comprising: - a planar antenna electrode with a main surface, wherein the main surface of the antenna electrode has at least one depression and at least one elevation, - a substrate on which the antenna electrode is formed, and - a ground electrode, namely a ground plane, which is arranged on one side of the substrate opposite the antenna electrode, - wherein - the antenna electrode and / or at least its main surface has a three-dimensional surface deformation in a third spatial direction, which is orthogonal to two spatial directions lateral to the main surface, and - the substrate has a sloping edge region such that on one side of the substrate opposite the antenna electrode, a ground plane is at least partially surrounded by the substrate, i.e.,a partially enclosed installation space is present,- wherein the sloping edge area forms inclined or vertical side walls of the installation space partially enclosed by the substrate, and- wherein the ground electrode is arranged between the side of the substrate opposite the antenna electrode and the installation space which is at least partially enclosed. Preferably, the sloping edge region of the substrate can be a sloping edge region arranged outside the antenna electrode and uncovered by the antenna electrode. Alternatively, it can be provided that the sloping edge area of ​​the substrate is covered by the antenna electrode. These embodiments are based on the understanding that three-dimensional modeling of a planar antenna electrode (patch) allows for targeted adjustment of the antenna characteristics to achieve a desired antenna profile. Additionally, utilizing the third dimension could create more installation space within the antenna element. Some embodiments relate to an antenna element comprising a planar antenna electrode having a main surface with at least one depression and one elevation. Three-dimensional modulation of the antenna surface allows, for example, for individual adjustment of the patch deformation to meet the antenna requirements within the available installation space. Furthermore, adaptation options can be created with regard to antenna characteristics (e.g., input impedance, radiation characteristics) and geometric constraints (e.g., available installation space). Additionally, the antenna type could be expanded to include a microstrip antenna. These deformations allow for the adaptation and optimization of the antennas based on both the available installation space and the antenna requirements. Both the antenna characteristics themselves (input impedance, radiation characteristics) and the geometric shape can be influenced in terms of utilizing a given installation space. In further embodiments, the main surface of the antenna electrode can have kinks in at least two different directions when viewed from above. This allows the directional characteristics of the antenna to be selectively influenced in different directions. Some embodiments refer to an antenna element with an antenna electrode whose main surface has a plurality of flat sub-surfaces. For example, a first sub-surface of the plurality of planar sub-surfaces and a second sub-surface of the plurality of planar sub-surfaces can adjoin each other along an edge and enclose an angle between 90° and less than 180° (or less than 175°) opening on a first side of the main surface. Additionally, the second sub-surface of the plurality of planar sub-surfaces and a third sub-surface of the plurality of planar sub-surfaces can adjoin each other along an edge and enclose an angle between 90° and less than 180° (or less than 175°) opening on a second side of the main surface opposite one of the first sides. This allows, for example, the edge length of the antenna electrode to be extended compared to a completely flat antenna electrode, thus changing the resonance frequency. In some embodiments, the antenna element comprises a substrate on which the antenna electrode is formed. Furthermore, a ground electrode can be arranged on one side of the substrate opposite the antenna electrode. In further embodiments, the substrate can have an edge region sloping down outside the antenna electrode, so that on one side of the substrate opposite the antenna electrode there is a space partially surrounded by the substrate. The installation space can be used, for example, to house electrical components. These electrical components can be designed, for instance, to supply the antenna electrode with signals to be transmitted or to further process signals received via the antenna electrode. In exemplary embodiments, the antenna electrode can have a feed point on a symmetry axis of the main surface of the antenna electrode. This allows, for example, the reception or transmission of circularly polarized signals. In some embodiments, the antenna electrode can have a plurality of slot-shaped recesses. This allows, for example, the circumferential edge length of the antenna electrode to be increased, thus reducing the area of ​​the antenna electrode. The slot-shaped recesses can be wider at the ends facing the center of the antenna electrode than at the opposite ends. Some embodiments refer to a receiver, transmitter or transceiver with an antenna element according to the proposed concept. Some embodiments refer to a vehicle with an antenna element according to the proposed concept. Some embodiments relate to a method for manufacturing an antenna element, which includes manufacturing a planar antenna electrode on a portion of a substrate surface. The portion of the substrate surface on which the antenna electrode is manufactured has at least one depression and one raised area. By manufacturing the antenna electrode on a substrate that defines the topography, for example, an antenna element with three-dimensional modulation of the antenna electrode can be produced in a simple way. Character description Further embodiments are described in more detail below with reference to the exemplary embodiments shown in the drawings, to which the exemplary embodiments are generally, but not entirely, limited. The drawings show: Fig. 1 a schematic representation of a top view and a side view of an antenna element; Fig. 2 a schematic representation of an antenna element with respect to a reference plane; Fig. 3 a schematic representation of an antenna element with respect to a reference plane; Fig. 4 a schematic representation of an antenna element with a plurality of planar sub-surfaces; Fig. 5 a schematic representation of an antenna element with bends in different directions; Fig. 6A a top view of an antenna element; Fig. 6B an oblique view of an antenna element; Fig. 7 a function of the reflection coefficient of an antenna element as a function of frequency; Fig.Figures 8A-8F show a schematic representation of different antenna element geometries; Figure 9A shows a top view of an antenna element; Figure 9B shows an oblique view of the antenna element shown in Figure 9A; Figure 10 shows a rear view of an antenna element; Figure 11 shows a schematic cross-section of an antenna element; Figure 12 shows the reflection coefficient of an antenna element as a function of frequency; Figure 13A shows the axial ratio of an antenna element as a function of frequency; Figure 13B shows the axial ratio of an antenna element as a function of angle; Figure 14 shows an antenna diagram of an antenna element; Figure 15 shows a block diagram of an antenna; Figure 16 shows a circuit diagram of a low-noise amplifier; Figure 17 shows the transmission coefficient of an antenna element as a function of frequency; and Fig. 18 a flowchart of a process for manufacturing an antenna element. Description Several embodiments are now described in more detail with reference to the accompanying drawings, in which some of these embodiments are illustrated. For the sake of clarity, the thickness dimensions of lines, layers, and / or regions may be exaggerated in the figures. In the following description of the accompanying figures, which merely show some exemplary embodiments, the same reference numerals can denote identical or comparable components. Furthermore, collective reference numerals can be used for components and objects that appear multiple times in an embodiment or in a drawing, but are described jointly with respect to one or more features. Components or objects described with the same or collective reference numerals can be identical with respect to one, several, or all features, such as their dimensions, but may also differ, unless the description explicitly or implicitly indicates otherwise. Although embodiments can be modified and altered in various ways, they are shown in the figures as examples and are described in detail herein. It should be clarified, however, that the intention is not to limit embodiments to the forms disclosed, but rather that they are intended to cover all functional and / or structural modifications, equivalents, and alternatives within the scope of the invention. The same reference numerals throughout the figure description denote identical or similar elements. Note that an element described as "connected" or "coupled" to another element may be directly connected or coupled to that element, or there may be intervening elements. Conversely, if an element is described as "directly connected" or "directly coupled" to another element, there are no intervening elements. Other terms used to describe the relationship between elements should be interpreted similarly (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). The terminology used herein serves only to describe specific embodiments and is not intended to limit the embodiments. As used herein, the singular forms "a," "an," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, it should be clarified that expressions such as "includes," "containing," "exhibits," "comprises," "comprising," and / or "indicating," as used herein, indicate the presence of the aforementioned features, integers, steps, workflows, elements, and / or components, but do not preclude the presence or addition of one or more features, integers, steps, workflows, elements, components, and / or groups thereof. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning that an average person skilled in the field to which the examples of implementation belong would ascribe to them. Furthermore, it should be clarified that expressions, e.g., those defined in commonly used dictionaries, are to be interpreted as having the meaning consistent with their meaning in the context of the relevant technology, and not in an idealized or overly formal sense, unless expressly defined herein. Fig. 1 shows a schematic top view and a side view of an antenna element according to an exemplary embodiment. The antenna element 100 comprises a planar antenna electrode 110. A main surface 112 of the antenna electrode 110 has at least one depression 114 and one raised area 116. The three-dimensional modeling of a planar antenna electrode (patch) makes it possible, for example, to selectively adjust the antenna characteristics to achieve a desired antenna characteristic. The antenna electrode 110, for example, is formed (e.g., deposited) on a substrate and has a planar geometry. In other words, the planar antenna electrode 110 extends significantly further in two spatial directions (e.g., lateral directions with respect to the main surface) than in a third spatial direction orthogonal to these two directions (e.g., vertical direction with respect to the main surface). For example, the antenna electrode 110 has an extent more than 10 times (or more than 30 times or more than 100 times) greater in two (orthogonal) lateral directions along the main surface 112 than in one vertical direction. In contrast, a dipole antenna or rod antenna, for example, has a significantly larger dimension in one direction than in the two directions orthogonal to it. The antenna electrode 110 is made, for example, of an electrically conductive material. The main surface 112 of the antenna electrode 110 is, for example, the surface of the front or back of the antenna electrode 110. For example, the main surface 112 of the antenna electrode 110 is the surface of the antenna electrode that faces a substrate (on which the antenna electrode is formed or arranged). The main surface 112 of the antenna electrode 110 is, for example, bounded by an edge of the antenna electrode 110. The length of the edge of the main surface 112 of the antenna electrode 110 can, for example, significantly determine the resonant frequency of the antenna. The main surface 112 of the antenna electrode 110 has at least one depression 114 and one elevation 116. In other words, the main surface 112 of the antenna electrode 110 has a geometry that deviates from a planar geometry, at least in a partial area. For example, a depression 114 in the surface can be an area-like, linear, or point-like part of the main surface 112 that is lower than adjacent parts of the main surface 112. Similarly, a elevation 116 can be an area-like, linear, or point-like part of the main surface 112 that is higher than adjacent parts of the main surface 112. In other words, a depression 114 and a elevation 116 are, for example, irregularities on the main surface 112 that extend in opposite directions.The depression 114 and the elevation 116 can, for example, be considered as a local minimum or local maximum in the topography of the main surface 112. The one or more depressions 114 and the one or more elevations 116 can, for example, be located within the main surface 112 (as shown schematically in Fig. 1), or at the edge of the main surface 112 (as described later in Fig. 5), or extend from within the main surface 112 to the edge of the main surface 112 (as shown later in Fig. 4). The antenna element 100 can comprise a substrate on which the antenna electrode 110 is formed. The substrate can, for example, consist of a dimensionally stable, electrically insulating material (e.g., plastic) and can already have a surface geometry that the antenna electrode 110 is intended to have. The antenna electrode 110 can be produced, for example, by depositing conductive material or by laser direct structuring (LDS) to metallize the substrate surface. Additionally, the antenna element 100 can include a ground electrode located on the side of the substrate opposite the antenna electrode 110. The ground electrode can be manufactured, for example, using the same process as the antenna electrode 110 or a different surface metallization process. During operation of the antenna element 100, the ground electrode can be held at a reference potential (ground potential) and the antenna electrode 110 can be supplied with a signal to be transmitted or a received signal can be tapped at the antenna electrode 110. The antenna electrode 110, for example, has at least one feed-in connection. A signal to be transmitted can be fed into the antenna electrode 110 for radiation via the feed-in connection, or a signal received via the antenna electrode 110 can be tapped off. The feed-in connection can, for example, be arranged on an axis of symmetry of the main surface 112 of the antenna electrode 110. The polarization property (e.g., linearly or circularly polarized) of transmitted or received signals can depend on the position of the feed-in connection. The antenna element 100 can, for example, receive and / or transmit electromagnetic waves. The antenna electrode 110 can be dimensioned according to the type and frequency of the signals to be transmitted or received. For example, the antenna electrode can have a maximum lateral extent (greatest dimension in one direction along the main surface) of less than 1 m (or less than 1 cm, less than 2 cm, less than 5 cm, less than 10 cm, or less than 50 cm) (e.g., for a GPS receiving antenna or mobile phone antenna). The antenna element 100 can be used, for example, as a transmitting and / or receiving antenna for a receiver, transmitter, or transceiver (e.g., a GPS receiver, a mobile phone, a base station, or a relay station). For instance, a proposed antenna element can be integrated into a GPS receiver, a mobile phone, a base station, or a computer, or it can be permanently installed on a vehicle (e.g., car, truck, motorcycle, boat, or aircraft) and used by a GPS receiver or another receiver, transmitter, or transceiver in the vehicle. Fig. 2 shows a schematic cross-section of an antenna element according to an exemplary embodiment. The antenna element 200 comprises a planar antenna electrode 110. A main surface 112 of the antenna electrode 110 has at least one depression 114 and one raised area 116. The at least one raised area 116 and the at least one depression 114 are located on opposite sides of a reference plane 210. The reference plane 210 is the plane that has the least square mean of the orthogonal distance 212 between the main surface 112 of the antenna electrode 110 and the reference plane 210. The reference plane 210 is a virtual plane that can have a different position relative to the different main surfaces of antenna electrodes of different antenna elements, depending on their geometries. However, for each main surface, its position is uniquely determined by its definition using the least square mean (RMS). The orthogonal distance between the main surface 112 and the reference plane 210 can be determined at any point on the main surface 112 and corresponds to the distance between the main surface 112 and the reference plane 210, measured orthogonally to the reference plane 210. For example, at least one depression 114 lies below (i.e., on a first side) the reference plane 210, and the elevation 116 lies above (i.e., on a second side) the reference plane 210. The depression 114 can be the point (or line or area) of the main surface 112 furthest from the reference surface 210 on the first side. Accordingly, the elevation 116 can be the point (or line or area) of the main surface 112 furthest from the reference surface 210 on the second side. If the main surface 112 has several depressions and / or elevations, these can have the same or different distances to the reference plane and accordingly represent local or global minima or maxima with respect to the topography of the main surface 112. The protrusion 116 and the depression 114 can vary in size depending on the desired antenna characteristics. For example, the protrusion 114 and the depression 116 can have an orthogonal distance to the reference plane of more than 0.1 mm (or more than 0.5 mm, more than 1 mm, or more than 5 mm). Additionally or alternatively, the protrusion 114 and the depression 116 can have an orthogonal distance to the reference plane of less than the maximum lateral extent Lmax (or less than 0.5 x Lmax, less than 0.2 x Lmax, less than 0.1 x Lmax, or less than 0.05 x Lmax) of the antenna electrode 110 (or the antenna element). For example, the elevation 114 and the depression 116 can have an orthogonal distance to the reference plane of less than 1 m (or less than 1 cm, less than 2 cm, less than 5 cm, less than 10 cm or less than 50 cm). The maximum lateral extent Lmax of the overall structure (the antenna electrode) can, for example, correspond to the longest edge length for essentially rectangular bases or to the diameter for essentially circular bases. The maximum lateral extent Lmax of antenna electrode 110 (patch size) can, for example, be less than 1 m (or less than 1 cm, less than 2 cm, less than 5 cm, less than 10 cm, or less than 50 cm). In an automotive context, for example, such an area could still be implemented effectively, e.g., by utilizing the roof surface. The surface modulation, i.e., the deflection around the reference surface, can, for example, range between a value greater than zero and Lmax. Fig. 2 shows an example of a main surface 112 with differently curved areas at the location of the depression 114 and the elevation 116. Due to the curved surface, for example at the location of the depression 114 and the elevation 116, no edge or kink is created, but a continuous surface. For comparison, Fig. 3 shows an embodiment of an antenna element 200 with an antenna electrode 110 having edges or kinks at the locations of one or more depressions 114 and one or more protrusions 116. For example, the main surface 112 can have several flat sub-surfaces which are connected to each other at the edges of the sub-surfaces and thus form edges or kinks. Further details of the antenna element of Fig. 2 or Fig. 3 are mentioned in connection with the proposed concept or one or more of the embodiments described above or below. The antenna element of Fig. 2 or Fig. 3 may have one or more optional additional features corresponding to one or more aspects explained in connection with the proposed concept or one or more of the embodiments described above or below (e.g., Fig. 1 or 4-18). Fig. 4 shows a schematic representation of an antenna element according to an exemplary embodiment. The antenna element 400 comprises a planar antenna electrode 110. A main surface 112 of the antenna electrode 110 has a plurality of planar sub-surfaces. A first sub-surface 410 and a second sub-surface 420 adjoin each other along an edge 412 and enclose an angle 422 opening on a first side of the main surface between 90° and 175° (or, for example, between 130° and 170°). Furthermore, the second sub-surface 420 of the plurality of planar sub-surfaces and a third sub-surface 420 of the plurality of planar sub-surfaces connect to each other along an edge 432 and enclose an angle 423 opening on one of the first sides of the main surface, between 90° and 175° (or e.g. between 130° and 170°). By using flat sub-surfaces that connect to each other at different angles, the edge length of the antenna electrode can be changed compared to a flat antenna electrode and / or the antenna characteristic can be adapted to a desired characteristic. A flat subsurface is a flat part of the main surface 112. Manufacturing-related surface roughness of the antenna electrode 110 is not taken into account. For example, the edge 412 between the first sub-surface 410 and the second sub-surface 420 can represent a linear elevation of the main surface 112, and the edge 432 between the third sub-surface 430 and the second sub-surface 420 can represent a linear depression of the main surface 112. The main surface 112 can be composed of more than three planar sub-surfaces. For example, the majority of sub-surfaces can comprise between 10 and 100 (or between 20 and 50) planar sub-surfaces. Further details of the antenna element of Fig. 4 are mentioned in connection with the proposed concept or one or more of the embodiments described above or below. The antenna element of Fig. 4 may have one or more optional additional features corresponding to one or more aspects explained in connection with the proposed concept or one or more of the embodiments described above or below (e.g., Figs. 1-3 or 5-18). Fig. 5 shows a schematic representation of an antenna element according to an exemplary embodiment. The antenna element 500 comprises a planar antenna electrode 110. In a top view, a main surface 112 of the antenna electrode 110 has kinks 510, 520 in at least two different directions 512, 522. By using an antenna element with a three-dimensionally modeled antenna electrode in multiple directions, the antenna characteristic can be very precisely adapted to a desired antenna characteristic. The two bend edges 510, 520 can, for example, both represent elevations or depressions of the main surface 112. Furthermore, one or more of the corners 530 of the edge of the antenna electrode can represent a depression or an elevation of the main surface 112. The at least two different directions 510, 520 can be two orthogonal directions or, for example, two directions that enclose an angle between 30° and 90°. Further details of the antenna element of Fig. 5 are mentioned in connection with the proposed concept or one or more of the embodiments described above or below. The antenna element of Fig. 5 may have one or more optional additional features corresponding to one or more aspects explained in connection with the proposed concept or one or more of the embodiments described above or below (e.g., Figs. 1-4 or 6A-18). Some embodiments relate to a surface-modulated patch antenna. For example, a method for miniaturizing a patch antenna, such as a modified shape of the patch surface (slot-shaped indentations), can be combined with three-dimensional deformation. For instance, the planar antenna electrode can have a plurality of slot-shaped indentations. For example, the deformation can be carried out as shown in Figs. 6A and 6B. This deformation (of the antenna electrode) can, for example, lead to a reduction in resonance for the same antenna base area, depending on the height of the raised points. Figs. 6A and 6B show, for example, embodiments of a slotted patch antenna (antenna electrode) with a three-dimensionally modulated surface. The antenna element 600 shown has an antenna electrode 110, which is shown in a top view in Fig. 6A. Here, g is the length of the antenna electrode 110, xs and ys are the lengths of the slotted recesses 620, and sp is the position of the feed point 630 on the diagonal of the antenna electrode 110. Fig. 6B shows an oblique view of the antenna electrode 110 formed on a substrate 640. For an increase in substrate area of ​​h = 2.7 mm, the input reflection coefficient is shown in Fig. 7 compared to a patch antenna with the same footprint. The input matching of the modulated slotted patch antenna 710 (h = 2.7 mm) is shown in comparison to a planar arrangement 720 on the same footprint. Figures 8A-8F show schematic diagrams of different types of surface modulation. As can be seen in Figures 8A-8C, this can be applied exclusively to the surface of the patch (the antenna electrode). This can, for example, lead to an extension of the radiating edges through shaping in the third dimension. Depending on the available space, this could allow for optimal adaptation of the antenna to it. Figures 8D-8E show further possible deformations, where these are carried out outside the actual patch area. In addition to adapting to the installation space, the straightening properties can also be influenced, for example, depending on the type of buckling. A combination of both deformations is also possible, as shown in Figure 8F. For example, all conceivable surface deformations have in common that they can influence the properties of the antennas, thus providing an additional possibility for improving the antenna properties in the context of their application. Figures 8A-8F show, for example, deformation of the patch antenna area, deformation outside the patch antenna area, and a combination thereof. The examples schematically depict antenna electrodes 110 and ground electrodes 810 arranged on opposite sides of a substrate 640. Some embodiments relate to an antenna element with an antenna electrode on a substrate. The substrate has a sloping edge region outside the antenna electrode, so that on one side of the substrate opposite the antenna electrode, there is a space partially enclosed by the substrate. For example, the sloping edge forms inclined or vertical side walls of a space partially enclosed by the substrate. Figures 9A (top view) and 9B (oblique view with parts shown partially transparent) show an example of an antenna element 900 with an antenna electrode 110 arranged on a substrate 640. The antenna electrode 110 has slotted recesses 620 (similar to those described in Figures 6A and 6B, slotted patch). The slotted recesses can be wider at the ends facing the center of the antenna electrode than at the opposite ends. Additionally, the substrate 640 (e.g., a 3D antenna substrate) is formed outside the antenna electrode 110, providing space for electronic components beneath the substrate 640.For example, electrical components for supplying the antenna electrode 110 with signals to be transmitted or for further processing signals received via the antenna electrode 110 can be arranged in the installation space partially surrounded by the substrate 640. The electronic components can, for example, be arranged on a crossbar 910 (e.g., circuit board, crossbar) located in the installation space and attached to the substrate. The length of the antenna element 900 is marked lpatch in this example (e.g., between 1 cm and 10 cm, e.g., 36.5 mm). For example, an angle between the sloping edge of the substrate 640 and a reference plane, as defined, for example, in connection with Fig. 2 and Fig. 3, can be between 20° and 90° (or between 30° and 60°). The sloping edge region has, for example, a width (measured from the antenna electrode) of more than 10% and less than 50% of the length of the antenna element lpatch. Figures 9A and 9B show an example of an antenna element with a surface-modulated slotted patch and an additional circumferential bend. In addition to surface modulation, an additional circumferential bend can be incorporated into the design of an antenna element, which can further reduce resonance while maintaining the same footprint. Furthermore, the resulting space beneath the antenna can be used, for example, for component integration. Fig. 10 shows an oblique view from the rear of the antenna element 900 shown in Figs. 9A and 9B. The crossbar is connected to the substrate or the ground electrode 810, for example, only at the feed terminal and the sloping edges of the substrate. This minimizes any disturbance of the antenna element's radiation pattern caused by the mounting of the crossbar 910 or the electronic components. The substrate 640 can, for example, be arranged on a base plate 1100 and have a shape such that a cavity for accommodating electrical components is present between the substrate 640 and the base plate 1100, as shown, for example, in the cross-section of Fig. 11. Figures 9A-11, for example, show a 3D patch antenna element. The concept shown in Figs. 9A and 9B can, for example, be used as an active antenna for civilian GPS (fcenter = 1.575 GHz). To improve its performance, a slotted patch antenna combined with 3D modulation of the substrate surface can be used. The proposed antenna can provide an input matching better than 10 dB in a 50 Ω system. Right-hand circular polarization (RHCP) with an axial ratio (AR) of less than 3 dB in the upper hemisphere can be achieved.For example, the slotted patch antenna can be evaluated and optimized for its intended application on a planar substrate. The patch antenna can be applied to differently modulated surfaces and re-adapted. The described modulation is achieved, for example, by folding the entire antenna substrate, including the mass surface area. Some possible designs investigated are shown in Figures 8A-8F. It can be observed that 3D modulation can lead to a reduction in the footprint, utilizing more vertical space. The originally planar structure of the patch antenna can be optimized considering a predefined integration space. This can help ensure optimal use of the available volume. Additionally, the resulting space under the modulated patch antenna can be used to integrate a circuit layout, as is done, for example, for the LNA in Figure 8A.15 and Fig. 16. Figure 6A shows the slotted, rectangular patch antenna. The slots are used, for example, to generate right-hand circular polarization and to reduce the antenna's geometric dimensions. Feeding is achieved, for example, using a coaxial feed positioned on the diagonal axis. Varying the feed position (630) can tune the input impedance, allowing the antenna to be matched, for example, to the input of the following LNA. Instead of straight slots (e.g., K.-L. Wong and J.-Y. Wu, "Single-feed small circularly polarized square microstrip antenna," Electronics Letters (Volume: 33, Issue: 22), pp. 1833-1834, 23 Oct. 1997), the slots in the central section can be widened, further extending the edges (Figure 6A). The antenna surface can be modulated below the patch surface, as shown, for example, in the side view corresponding to Fig. 9A, Fig. 9B and Fig. 10 (Fig. 11). Circular polarization is achieved, for example, by maintaining symmetries along the x- and y-axes as much as possible. Modulation extends the edge length and slot width on the same base area, thereby reducing the resonant frequency, for example. In addition to surface modulation directly beneath the patch surface, the side sections can be folded downwards and slightly outwards (Fig. 11) to provide, for example, additional space for later integration of an LNA circuit. In one example, antenna optimization can result in a total height of htotal = 12.5 mm and a base length of lbase = 64 mm. The length of the modulated patch can be, for example, lPatch = 36.5 mm, and the height, due to patch modulation, can be hPatch = 3 mm (maximum vertical distance between the highest and lowest points of the main surface of the antenna electrode).The resulting space beneath the antenna can be used to install a small crossbeam on which the circuit elements can be placed. This crossbeam is attached at only three points, for example, to avoid or minimize interference with the metallization of the ground plane beneath the patch panel and the main surface current distribution. This procedure has only a negligible impact on the antenna's functionality. A fixed point in the center of the crossbeam can be used to connect the antenna feed point to the input of the subsequent LNA circuit, as shown in Fig. 11. The following section discusses, by way of example, both measurement and simulation results for an antenna element shown in Fig. 9A-11. The relative permittivity of the epoxy resin used is, for example, εr = 3.4 and the loss tangent is tan δ = 0.018, both values ​​being measured at 1 GHz. Since the permittivity of this material is, for example, lower than that of substrate materials often used for GPS patch antennas, the antenna dimensions, for example, increase. The achieved gain can be reduced due to dielectric losses. In series production, an LDS material could be used for the injection-molded part. LDS-capable materials are available with properties comparable to those of materials typically used for RF applications (A. Friedrich, QH Dao and B.Geck, “Characterization of Electromagnetic Properties of MID Materials for High Frequency Applications up to 67 GHz,” in 11th International Congress Molded Interconnect Devices 2014, Nuremberg / Fuerth, Germany, 2014). Furthermore, changes in permittivity due to the LDS coating of the epoxy resin part during the simulations can be taken into account. For this reason, the permittivity value for all simulations was set to εr = 3.29. For the measurements and corresponding simulations, the antenna element of Fig. 9A-11 was connected to the feed point via an SMA connector (SubMiniature version A) for PCB mounting and placed on an aluminum plate measuring 250 x 250 x 3 mm. Fig. 12 shows the simulated and measured reflection loss of the antenna. In the targeted frequency range, an input matching better than 10 dB is achieved (indicated by a line). The measured and simulated resonant frequency deviates by approximately 25 MHz. This may be due to differences in the resulting permittivity of the LDS-coated epoxy resin. The radiation characteristics are evaluated at the respective resonant frequency. Fig. 13A shows that the axis ratio AR is minimal at the resonant frequency for both the measured and simulated values.An AR of 1.5 dB is obtained in the simulations and 2.8 dB for the measured structure. Fig. 13B shows that the maximum AR value for almost the entire half-space is less than 6 dB (simulated) and less than 8 dB (measured) in cases where interference is expected. The radiation patterns in Fig. 14 show good agreement between the measurement and simulation results. The maximum antenna gain in this example is approximately -2.5 dBi at the zenith. The 3D antenna design shown in Fig. 9A-11 allows the integration of circuit components, such as an LNA or a matching network, near the feed point. For an active antenna, integrating the LNA close to the feed point is particularly important for reducing the system noise figure. Another benefit is that the ground plane of the patch antenna provides additional shielding for the circuitry on the crossbar against electromagnetic interference. The low signal strengths encountered, for example, in GPS applications underscore the importance of this. In one proposed example for implementing the LNA, a two-stage approach is used. Fig. 15 shows a block diagram of an amplifier circuit that can be connected to a proposed antenna element. Since the first part of an RF system has the greatest impact on the overall system noise figure, the first amplifier stage 1510 can minimize the noise figure. Following this first stage is, for example, a surface acoustic wave (SAW) filter 1520 (EPCOS SAW RF filter B3522 [EPCOS AG, "SAW Components-SAW RF filter GPS - B3522, Version 2.5," EPCOS AG, Munich, 2013]). The second amplifier stage 1530 does not need to be as low-noise as the first stage. Thus, other aspects can be considered as design goals depending on the specific application. The supply voltage can be set to provide 3.3 V phantom power. The integration space can be taken into account for the LNA circuit layout. Specifically, this means, for example, that the circuit design can fit on the crossbar and be implemented using the LDS ProtoPaint method. The back of the crossbar can be metallized and connected to the ground of the patch antenna. This allows the patch antenna and the LNA circuit to share the same ground reference. As mentioned previously, minimizing the noise figure can be a design goal for the first LNA stage. Furthermore, a small bandwidth could ensure the suppression of unwanted signals, particularly in the mobile phone communication frequency range. With regard to these potential requirements, the amplifier design can be implemented using noise matching instead of impedance matching. Figure 16 shows a schematic representation of the first stage 1510 of the designed LNA. This is, for example, a Class-A amplifier based on the Infineon BFP640FESD transistor and a reference design from the manufacturer (T. Anthony and DC-I. Lin, "LNA BFP640FESD for GPS 1575MHz Application - Application Note: AN194," Infineon, 2010). The operating point, set via resistors R1 and R2, can be optimized for a minimum noise figure, which is primarily influenced by the collector current.To ensure that the bias voltage is independent of the RF section of the circuit, two coupling capacitors (C1, C2) can be integrated to isolate the DC voltage from the rest of the circuit. These capacitors can also be used to reduce the complexity of the matching network in the next step. For example, the input noise matching is achieved with C1, and an inductive element L1 can be connected to ground via a large capacitor C3. Capacitor C3 acts as a short circuit for RF signals and can also prevent the noise matching from being affected by the bias resistors. The DC supply is provided via L1. To achieve better frequency selectivity, the transistor can be loaded with a series resonant circuit connected to its collector (L2, C4). The bias resistor R2 has a damping effect.Near the resonance of the LC circuit, a short circuit to ground can reduce the gain. This technique allows a frequency range to be excluded from amplification, thus achieving selectivity. To ensure circuit stability, an additional resistor R3 can be connected in series with the coupling capacitor C2, in parallel with the output. These components can further reduce the gain at lower frequencies. The final step is, for example, adapting the output for power transmission. This can be achieved using an LC series circuit, which acts as an additional low-pass filter (C5, L3). The simulated values ​​for the first stage of the LNA 1510 show a noise figure of Fnoise = 0.76 dB and a gain GLNA = 17 dB. The second stage of the amplifier can be a SAW filter 1520 for GPS applications. It improves, for example, the selectivity of the amplifier. The same design as for the first stage can be used for the second LNA stage 150. The measured and simulated RF characteristics of the two-stage LNA, as described above, are discussed below using an example. The layout of the two-stage amplifier takes into account, for example, the space available on the crossbeam beneath the 3D patch antenna shown in Fig. 9A-11. Fig. 10 shows, for example, a realized LNA circuit integrated on the crossbeam of the proposed antenna. For measurements, an SMA connector is used on the output side. Power can be supplied via a bias tap. On the input side, a semi-rigid cable can be used, for example, to establish contact with the LNA at the antenna feed point without connecting the antenna itself. Figure 17 shows the magnitude of the transmission coefficient. The gain in the desired frequency range—indicated by a line—is approximately 36 dB (simulated) and 28.3 dB (measured). The differences may be due to component tolerances. Furthermore, the measurement results show higher out-of-band suppression. With respect to the carrier, the attenuation at the mobile phone communication frequencies is approximately 73 dB at 827.5 MHz and 55 dB at 1885 MHz. The 1 dB compression point is approximately P1dB,IN = 19.9 dBm. This value is comparable to other GPS amplifiers. The measured, band-internal IIP3 is IIP3 = -5.1 dBm for the input signals f1 = 1.574 GHz and f2 = 1.576 GHz with an input power of Pin = -35 dBm. The circuit design is, for example, fully integrated under the 3D patch antenna and can be implemented using the 3D LDS method. An example of another LNA is also shown in M / A-COM Technology Solutions Inc., "MAALSS0042-Low Noise Amplifier 1.575 GHz Datasheet, Rev. Vl". Some embodiments relate to folded planar antenna elements (folded patches), an active three-dimensional GPS patch antenna using MID technology and / or geometric modulation of microstrip line antennas or patch antennas. Examples refer to a three-dimensional (3D) active antenna that can be operated in a civil global positioning system (GPS) for an automotive application. When implementing the antenna, an aspect of the proposed concept can be used, combining a slotted patch antenna with 3D surface modulation of the antenna substrate. This allows for optimization or improvement of the antenna dimensions within a given installation space. Furthermore, the space gained through the modulation of the antenna surface can be used to integrate the circuitry of a low-noise amplifier (LNA).This two-stage LNA, which can be specifically designed for this application, can be housed directly beneath the 3D surface of the antenna, thereby achieving a minimal or shorter transmit line length between the feed point and the LNA input. Implementation can be achieved using three-dimensional injection-molded interconnect device (3D-MID) technology, where the 3D surface can be metallized using laser direct structuring (LDS). The ability to create three-dimensional antenna substrates allows, for example, the design of space-efficient and functional antennas and RF circuits. Especially in applications where antennas and circuits can be combined, 3D-MID technology can reduce complexity, as both can be implemented as a single component. In the automotive sector, the flexibility of 3D-MID can also enable the unobtrusive integration of radio services into the vehicle design (A. Friedrich, B. Geek, O. Klemp and H. Kellermann, “On the design of a 3D LTE antenna for automotive applications based on MID technology,” in European Microwave Conference (EuMC), 6-10 Oct. 2013, Nuremberg, 2013). The flexibility of the production process can be cited as one aspect in meeting these requirements. 3D-MID (molded interconnect device) technology allows virtually any shaped surface of a plastic part to be metallized, offering the necessary high degree of flexibility. This is a frequently used process, particularly in the mobile communications industry, where the plastic casing of mobile phones is functionalized as a substrate material for antennas and RF circuits. In times of decreasing space availability, this is an efficient method utilizing a predefined installation area. Various methods exist for metallizing these plastic parts (J. Franke, Three-Dimensional Molded Interconnect Devices (3D-MID) - Materials, Manufacturing, Assembly and Applications for Injection Molded Circuit Carriers, Munich: Carl Hanser Verlag, 2014). One method already used for the mass production of RF and non-RF applications is the LDS (laser direct structuring) process. This may require a special plastic material doped with an organic metal complex. After the surface of the structure has been activated with a laser, the activated areas can absorb copper in a current-free copper bath (R. Schlüter, B. Rösener, J. Kickelhain and G.Naundorf, “Completely additive laser-based process for the production of 3D MIDs—The LPKF LDS Process,” in 5th International Congress Molded Interconnect Devices, Erlangen, 2002). As an alternative to an injection-molded part with the LDS-capable special plastic, a coating called LPKF ProtoPaint can be used. In this way, a 3D circuit carrier can be produced using standard stereolithography processes. The LDS capability can then be achieved by coating. This flexible method can be used to implement an active antenna system according to the proposed concept. Several examples of an active patch antenna were presented and discussed. According to the proposed concept, the surface of the patch antenna was modulated and folded, thereby reducing the antenna's footprint while utilizing additional vertical space. The resulting space beneath the antenna can be used for integrating a line-noise ablation (LNA) circuit. For example, an antenna element can be fabricated using a stereolithography process, and metallization can be achieved using LPKF ProtoPaint. A proposed LNA can be designed to be integrated beneath the antenna surface, fulfilling the requirements for a GPS LNA. This proposed active antenna serves as an example demonstrating the potential of 3D-MID technology to enhance antenna and circuit design for future radio system requirements, particularly in automotive applications. Based on the proposed concept, planar patch antenna designs, for example, can be avoided. These designs, due to their directional properties perpendicular to the surface, prevent or limit the use of applications requiring omnidirectional radiation patterns (e.g., terrestrial radio applications). In contrast to the proposed design, the 2D design is severely limited by the available installation space, as the third dimension remains unused. Therefore, the need for space-saving modifications, which are only possible through planar miniaturization methods and result in a deterioration of antenna characteristics, can be avoided or reduced. Three-dimensional modulation of the antenna surface allows both the antenna surface itself and the associated ground plane to be deformed in order to optimize the antenna characteristics. This can significantly expand the possibilities for optimizing this type of antenna and also for adapting it to given installation spaces. Constructively, this can be achieved by deforming the surface of a plastic part used as an antenna substrate. The subsequent metallization can then take place on the three-dimensional surface. Fig. 18 shows a flowchart of a method for manufacturing an antenna element. The method 1800 comprises manufacturing 1810 a planar antenna electrode on a portion of the surface of a substrate. The portion of the substrate surface on which the antenna electrode is manufactured has at least one depression and one raised area. By manufacturing an antenna electrode on a pre-formed substrate, an antenna element with a three-dimensionally modulated antenna electrode can be produced in a simple manner. Additionally, the method 1800 can, for example, include the production 1820 of a ground electrode on one side of the substrate opposite the antenna electrode. Constructively, for example, the surface of a plastic part used as an antenna substrate for a patch antenna can be deformed (or directly manufactured as an injection-molded part). Subsequent metallization can then be carried out on the three-dimensional surface. Further details of the method of Fig. 18 are mentioned in connection with the proposed concept or one or more of the embodiments described above or below. The method of Fig. 18 may have one or more optional additional features corresponding to one or more aspects explained in connection with the proposed concept or one or more of the embodiments described above or below (e.g., Figs. 1-17). Another embodiment is a computer program for carrying out at least one of the methods described above, provided the computer program runs on a computer, a processor, or a programmable hardware component. Another embodiment is a digital storage medium that is machine- or computer-readable and that contains electronically readable control signals which can interact with a programmable hardware component to execute one of the methods described above. The features disclosed in the foregoing description, the following claims and the accompanying figures can be important and implemented individually or in any combination for the realization of an embodiment in its various configurations. Although some aspects have been described in connection with a device, it is understood that these aspects also constitute a description of the corresponding process, so that a block or component of a device is also to be understood as a corresponding process step or as a feature of a process step. Similarly, aspects described in connection with or as a process step also constitute a description of a corresponding block, detail, or feature of a corresponding device. The embodiments described above merely illustrate the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be obvious to other people skilled in the art. Therefore, it is intended that the invention be limited only by the scope of protection set forth in the following claims and not by the specific details presented herein by way of description and explanation of the embodiments.

Claims

Antenna element (100, 200, 300, 400, 500, 600, 900), comprising: - a planar antenna electrode (110) with a main surface (112), wherein the main surface (112) of the antenna electrode (110) has at least one depression (114) and at least one elevation (116), - a substrate (640) on which the antenna electrode (110) is formed, and - a ground electrode (810), namely a ground plane, which is arranged on one side of the substrate (640) opposite the antenna electrode (110), - wherein - the antenna electrode (110) and / or at least its main surface (112) has a three-dimensional surface deformation in a third spatial direction which is orthogonal to two spatial directions lateral to the main surface (112), and - the substrate (640) has a has a sloping edge region, such that on one side of the substrate (640) opposite the antenna electrode (110) there is a surface at least partially surrounded by the substrate (640), i.e.a partially enclosed installation space is available,- wherein the sloping edge area forms inclined or vertical side walls of the installation space partially enclosed by the substrate (640), and- wherein the ground electrode (810) is arranged between- the side of the substrate (640) opposite the antenna electrode (110) and- the installation space which is at least partially enclosed. Antenna element according to claim 1, wherein the sloping edge region of the substrate (640) is a sloping edge region arranged outside the antenna electrode (110) and is not covered by the antenna electrode (110). Antenna element according to claim 1, wherein the sloping edge region of the substrate (640) is covered by the antenna electrode (110). Antenna element according to one of claims 1 to 3, wherein the at least one elevation (116) and the at least one depression (114) are located on opposite sides of a reference plane, wherein the reference plane (210) is the plane which has the smallest square mean value of the orthogonal distance of the main surface (112) of the antenna electrode (110) to the reference plane (210). Antenna element according to claim 4, wherein the elevation (116) and the depression (114) have an orthogonal distance to the reference plane (210) of more than 0.1 mm. Antenna element according to claim 4 or 5, wherein the elevation (116) and the depression (114) have an orthogonal distance to the reference plane (210) of less than a maximum lateral extent of the antenna electrode (110). Antenna element according to one of the preceding claims, wherein the elevation (116) is an area-shaped, point-shaped or linear elevation and the depression (114) is an area-shaped, point-shaped or linear depression. Antenna element according to one of the preceding claims, wherein the main surface (112) of the antenna electrode (110) has kinks in at least two different directions in a top view. Antenna element according to one of the preceding claims, wherein the main surface (112) of the antenna electrode (110) has a plurality of planar sub-surfaces. Antenna element according to claim 9, wherein a first partial surface (410) of the plurality of planar partial surfaces and a second partial surface (420) of the plurality of planar partial surfaces connect to each other along an edge (412) and enclose an angle (422) opening on a first side of the main surface (112) between 90° and less than 180°, and wherein the second partial surface (420) of the plurality of planar partial surfaces and a third partial surface (430) of the plurality of planar partial surfaces connect to each other along another edge (432) and enclose an angle (423) opening on a second side of the main surface (112) opposite the first side, between 90° and less than 180°. Antenna element according to one of the preceding claims, wherein electrical components for supplying the antenna electrode (110) with signals to be transmitted or for further processing of signals received via the antenna electrode (110) are arranged in the installation space at least partially surrounded by the substrate (640). Antenna element according to one of the preceding claims, wherein the substrate (640) is arranged on a base plate (1100) and has a shape such that a cavity for accommodating electrical components is provided between the substrate (640) and the base plate (1100). Antenna element according to one of the preceding claims, wherein the antenna electrode (110) has a feed connection (630) on an axis of symmetry of the main surface (112) of the antenna electrode (110). Antenna element according to one of the preceding claims, wherein the antenna electrode (110) has a maximum lateral extent of less than 1 m. Antenna element according to one of the preceding claims, wherein the antenna electrode (110) has a plurality of slot-shaped recesses (620). Antenna element according to claim 15, wherein the slot-shaped recesses (620) at the ends of the slot-shaped recesses (620) facing the center of the antenna electrode (110) are wider than at the opposite ends of the slot-shaped recesses (620). Receiver, transmitter or trans-receiver with an antenna element according to any of the preceding claims. Vehicle with at least one antenna element according to one of claims 1 to 16 and / or a receiver, transmitter and / or transceiver according to claim 17. Method (1800) for manufacturing an antenna element according to any one of claims 1 to 16, comprising at least the following step:- Manufacturing (1810) a planar antenna electrode (110) on a part of a surface of a substrate (640), wherein the part of the surface of the substrate (640) on which the antenna electrode (110) is manufactured has at least one depression (114) and at least one elevation (116).

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