Steel component with an integrated antenna and method for producing a steel component with an integrated antenna

Abstract

The invention provides a steel component (100), a cold-formed steel component (100), and a method for manufacturing a steel component (100). The steel component (100) comprises: a base substrate (110) made of a coated or uncoated steel sheet; an intermediate structure (120) comprising at least one dielectric functional layer (122) based on a paint, applied directly to the base substrate; and at least one structured conductive layer (130) applied to the intermediate structure (120), in which at least one antenna surface structure (140) is formed, which, together with the base substrate (110) as the base surface and with the intermediate structure (120) as the dielectric, forms at least one antenna (150).

Description

Technical area

[0001] The present invention relates to a steel component and a method for producing a steel component. The steel component, in particular, has an integrated antenna that advantageously utilizes the properties of the steel component. Technical background

[0002] Rooms enclosed by metallic or metallized surfaces significantly attenuate electromagnetic waves. This is often undesirable, especially when it comes to buildings with metallic facades or vehicles such as trains, cars, trucks, ships, airplanes, etc. In some cases, complex

[0003] Signal amplification units are installed. These not only require additional manufacturing or assembly steps, but usually also external supply or discharge lines for signal transmission. With such solutions, it is often undesirable that the subsequently attached antenna structures stand out from the surface to which they are attached. This can be not only unsightly but also susceptible to environmental influences and damage.

[0004] US 2021 / 280 963 A1 describes a method for forming an antenna on the surface of a vehicle, which comprises forming a recess in a surface of the vehicle and inserting the antenna into the slot. However, this method also requires various steps after the manufacture of the corresponding vehicle component, in particular forming the recess and inserting the antenna. Furthermore, it is often undesirable for components to be provided with openings, as this can promote corrosion or other deterioration, for example, a reduction in the stability of the component.

[0005] EP 1 630 730 B1 describes a system comprising a transponder with a patch antenna and an object with a metallic component. The transponder has a transponder chip and a metal surface that is galvanically or capacitively coupled to the metallic component of the object. The transponder is attached to the object with an adhesive layer. Such a system is susceptible to environmental influences and damage. The system is also not an integral part of a steel component and thus cannot be produced—even partially—in integrated steps during the production of the steel component.

[0006] State-of-the-art patch antennas are constructed with highly specialized, highly optimized high-frequency dielectrics, particularly laminates, for antenna function. However, such high-frequency dielectrics are difficult to handle; in particular, they cannot be directly applied or printed onto steel components. Furthermore, for stability reasons, they often require the insertion of fibers, such as glass fiber mats, which in turn impairs the antenna properties. Summary of the invention

[0007] It is therefore an object of the present invention to provide a steel component that is robust against environmental influences and yet has a functional antenna, which can preferably be formed on the steel component with as few additional manufacturing steps as possible. A further object of the invention is to provide a method for producing a steel component with an antenna, which requires as few additional steps as possible and is thus simple to implement and cost-effective to use.

[0008] These problems are solved by the subject-matter of the independent patent claims.

[0009] Accordingly, a steel component is provided comprising: a base substrate made of a coated or uncoated steel sheet; an intermediate structure comprising at least one lacquer-based dielectric functional layer applied directly to the base substrate; and at least one structured conductive layer applied to the intermediate structure, in which at least one antenna surface structure is formed, which, together with the base substrate as a base surface (or: ground surface) and with the intermediate structure as a dielectric (or: spacer), forms at least one antenna.

[0010] The dielectric functional coating based on a paint base applied directly to the base substrate can, in particular, be a primer coating system (also known as a primer layer). The primer coating system can be applied to the coated or uncoated steel sheet by means of coil coating and can, for example, be between 6 micrometers and 100 micrometers (pm) thick, in particular between 60 micrometers and 90 micrometers, for example 80 micrometers thick. The coated steel sheet can, in particular, be a galvanized steel sheet, i.e., a steel sheet coated with zinc or a zinc alloy, or a steel sheet coated with aluminum or an aluminum alloy.

[0011] The lacquer-based dielectric functional layer applied directly to the base substrate is preferably deposited or printed directly onto the base substrate. The individual elements or layers of the intermediate structure are also preferably deposited or printed directly onto one another. The structured conductive layer is also preferably deposited or printed directly onto the intermediate structure. The intermediate structure and the structured conductive layer are thus advantageously not detachable from the base substrate, or not detachable without destruction, which increases the structural durability of the steel component as a whole. Each dielectric layer, in particular lacquer-based ones, is also advantageously fiber-free, i.e., it does not contain any fibers such as a stabilizing glass fiber fabric. This improved the antenna properties of the antenna, while at the same time the base substrate ensured good stability.

[0012] The basecoat system or primer layer preferably comprises corrosion protection particles. Since these can partially interfere with the antenna function, in some embodiments the primer layer can be formed as a thin-film primer with thicknesses between 6 micrometers and 10 micrometers, in particular with a thickness of approximately or exactly 6 micrometers.

[0013] The intermediate structure can comprise additional dielectric functional layers. Several or even all of the additional dielectric functional layers can also be lacquer-based. The intermediate structure can also comprise conductive layers, for example, to form supply lines or drain lines, i.e., electrical contact lines, to the antenna surface structure.

[0014] The structured conductive layer can, in particular, be a structured metallic layer. Alternatively, it can also comprise or consist of a carbon-based conductive material, e.g., graphene or graphite.

[0015] The term "antenna surface structure" is intended to describe a component of an antenna consisting of a metallic surface, a metallic border or loop, or another implementation form, according to which essentially two-dimensional structures acting on electromagnetic waves can be formed. Examples of such antenna surface structures according to various antenna types will be explained in more detail below and will become apparent, in particular, from the designation of the corresponding antenna. The area of ​​the antenna surface structure is considered to be the area itself for a metallic surface, the enclosed area for a metallic border or loop, and the corresponding area that effectively acts on electromagnetic waves for other implementation forms.

[0016] The antenna surface structure can in particular be a planar antenna surface structure, i.e. it can be arranged completely in one plane. This can be the case before or after forming (in particular cold forming) of the steel component. In other words, the steel component can be designed such that the antenna surface structure is planar before forming and non-planar after forming, or such that the antenna surface structure is planar before and after forming. The latter case can occur, for example, if only sections of the steel component in which no antenna surface structure is arranged are formed, for example only sections which contain supply lines, discharge lines, or connecting lines (i.e. electrical contact lines) of the antennas and / or sections in which no structured conductive layer is formed.In some variants, it may also be the case that the antenna surface structure is non-planar before forming and planar after forming. The same applies to a (respective) electrical contact line of the antenna surface structure, which may also be planar or non-planar, entirely or partially, before or after forming.

[0017] It is understood that more than one antenna can be formed in the structured conductive layer, for example, an antenna array, in particular a transmitting / receiving arrangement or a retro-reflector arrangement. It can be advantageous if all antennas in the structured conductive layer are implemented in the same way, i.e., in particular, have the same antenna surface structure. However, it is also possible for antennas with different technical bases (i.e., different antenna types) and / or different antenna surface structures to be formed in the structured conductive layer.

[0018] If multiple antennas are provided in the steel component, these antennas can be interconnected, in particular, within the structured conductive layer. This means that the structured conductive layer can also have connecting lines between multiple antennas, especially between multiple antenna surface structures. In particular, if the antennas are part of a (signal) transmitting and / or (signal) receiving arrangement, parts of the electrical contact lines (e.g., from a signal generator to the antenna) and / or signal leads (e.g., from the antenna to a signal amplifier) ​​can also be formed within the structured conductive layer.

[0019] The at least one antenna in the steel component can be designed in particular for a frequency band within a frequency range of 30 MHz to 80 GHz, for example within a frequency range of 2 GHz to 7 GHz, of 55 GHz to 85 GHz, or of 850 MHz to 930 MHz.

[0020] The at least one antenna may also be optimized for other frequency bands, which in particular includes that the antenna is optimized for at least one frequency in such a frequency band, or substantially uniformly to all frequencies of the frequency band.

[0021] For example, the antenna can be optimized for one or more of the license-free ISM frequency bands or ISM frequencies, such as: 315MHz 433-435 MHz 900-915 MHz 2400-2500 MHz 5725-5875 MHz or 24-24.6 GHz.

[0022] The at least one antenna can alternatively be optimized for at least one LTE frequency band, such as one of the following: LTE band 01 (FDD2100 - IMT) LTE band 03 (FDD1800 - DCS) LTE band 07 (FDD2600 - IMT-E) LTE band 08 (FDD900 - E-GSM) LTE band 20 (FDD800 - EUDD) LTE band 28 (FDD700 - APT)

[0023] The at least one antenna can alternatively be optimized for at least one GSM frequency band, such as one of the following: 824 MHz to 894 MHz 876 MHz to 960MHz 1710 MHz to 1880MHz 1850 MHz to 1990MHz

[0024] The at least one antenna can alternatively be optimized for at least one WLAN frequency band, one WIFI frequency band or one Bluetooth frequency band, for example one of the following: 2400MHz to 2483MHz or 2497MHz 5150 MHz to 5725MHz 57 GHz to 71GHz

[0025] The at least one antenna can alternatively be optimized for at least one frequency band for RFID applications, for example for 868 MHz to 930 MHz.

[0026] The at least one antenna may alternatively be optimized for at least one Short Range Devices (SRD) frequency band, for example for one of the following: 863MHz to 870MHz 902MHz - 928MHz

[0027] The at least one antenna can alternatively be optimized for at least one GNSS frequency band, for example for 1176.45 MHz, 1207.14 MHz, 1227.6 MHz, 1278.75 MHz and / or 1575.42 MHz.

[0028] The at least one antenna can alternatively be optimized for at least one radio frequency band, in particular in the VHF range, for example for a frequency band from 87.5 MHz to 108 MHz.

[0029] The at least one antenna can alternatively be optimized for at least one radar frequency band, for example, the L-band, the S-band, the C-band, the X-band, the K-band, the Ka-band, the V-band, the W-band (each according to ITU) and / or a band from 76 GHz to 81 GHz. These frequency bands are particularly advantageous for steel components with a retro-reflector arrangement.

[0030] The at least one antenna can alternatively be optimized for at least one IoT frequency band, for example for a ZigBee frequency band around 868 MHz, 915 MHz and / or 2450 MHz, or for frequency bands such as 902 MHz to 928 MHz, 863 MHz - 870 MHz, 779 MHz to 787 MHz or 470 MHz to 510 MHz.

[0031] One of the great advantages of the present invention is that steel components, in particular coated or uncoated steel sheets, are often already provided with one (or more) paint-based layer(s), which can be used according to the invention as dielectric functional layer(s). The relatively simple yet fully functional structure of the embodiment according to the present invention can thus be implemented with little additional effort and, at the same time, has many structural advantages: Due to the integral arrangement of the antenna in a layer system, the antenna is largely insensitive to environmental influences. The steel component is advantageously unperforated, i.e., it has no holes, slots, or the like, which increases the robustness of the steel component against both physical and chemical influences (oxidation, etc.).

[0032] The steel component constructed in this way is not only highly resilient, but also aesthetically pleasing and offers a high degree of design freedom.

[0033] It can be used, for example, in vehicle components, especially on the exterior walls of vehicle components, where low airflow resistance combined with good antenna reception is desired. Another application is in metallic building facades, for example, as a device designed to receive electromagnetic signals on the exterior of the building and transmit them to the interior, optionally amplifying them (e.g., a "repeater").

[0034] Since the steel component according to the invention is very robust and can also be provided with high curvatures, it is also suitable for use in or as a wearable accessory, such as a bracelet, a component of a watch or smartwatch, or the like.

[0035] A further advantage of the present invention is the possibility of forming the steel component with a particularly low height of the additional layers above the steel sheet. This can further increase the design freedom in the use of the steel component.

[0036] In the following, we will repeatedly refer to the properties of "the at least one antenna" of the steel component. It is understood that this always means that the corresponding properties can also apply to a large number of antennas, or that different properties can apply to different antennas on one and the same steel component.

[0037] As already mentioned, the at least one antenna can be designed according to a variety of antenna types known in the prior art with different antenna surface structures. In particular, the at least one antenna can be designed as one of the following types of antennas (antenna types): as a patch antenna; as a grounded coplanar patch antenna; as a slotted patch antenna; as a slot antenna (or: slot-type antenna); as a folded monopole antenna; as a loop antenna; as a folded loop antenna; and / or as a planar inverted-F antenna.

[0038] According to some preferred embodiments, variants, or refinements of embodiments, at least one antenna is embodied as a grounded coplanar patch antenna. For this purpose, the at least one antenna surface structure can be at least partially surrounded by a grounded (or: to be grounded) surface structure of the structured conductive layer through a trench structure left open in the structured conductive layer. In other words, the structured conductive layer can have a grounded, or to be grounded, section, which largely or completely encloses at least one antenna surface structure in the structured conductive layer that is galvanically isolated from it.

[0039] According to some preferred embodiments, variants, or refinements of embodiments, the at least one antenna is designed as a slot antenna (or slot-type antenna). Such slot-type antennas typically have recesses and / or slots in the base substrate, i.e., in the coated or uncoated steel sheet.

[0040] According to some preferred embodiments, variants, or refinements of embodiments, an electrical contact line to the at least one antenna surface structure is formed entirely or partially in the intermediate structure and / or the structured conductive layer. In a microstrip line or the grounded coplanar patch antenna, at least part of the electrical contact line is arranged in the structured conductive layer. In a coaxial feed line, or in variants in which the electrical contact line is arranged parallel to the structured conductive layer, this electrical contact line can be formed entirely or partially in the intermediate structure. This can be the case, for example, with aperture-coupled feed lines or proximity-coupled feed lines.

[0041] The electrical contact lines can be designed as in conventional printed circuit board technology, i.e., depending on the antenna type (or type of radiating / receiving element), variants such as microstrip lines (single-ended), differential line systems, grounded-coplanar variants, etc., are feasible. The specific dimensions depend primarily on the geometry, in particular the thickness d and the dielectric properties of the intermediate structure, and can be adapted by a specialist for the desired frequency range and the antenna impedance.

[0042] For example, with a thickness d of the intermediate structure of 100 µm < d < 180 µm, the typical optimal width of a microstrip line in the impedance window of 25-75 ohms is 0.2-0.9 mm.

[0043] Several options are available for connecting the electrical contact lines, similar to those used for traditional printed circuit boards. In addition to typical connector solutions, spring contacts, solder connections, impedance-matched adhesive connections, and edge-mount connections are also conceivable and have shown good results in tests.

[0044] According to some preferred embodiments, variants, or refinements of embodiments, the intermediate structure has a thickness of between approximately (or exactly) 30 micrometers and approximately (or exactly) 300 micrometers, preferably between approximately (or exactly) 110 micrometers and approximately (or exactly) 230 micrometers, particularly preferably between approximately (or exactly) 140 micrometers and approximately (or exactly) 200 micrometers, for example approximately (or exactly) 180 micrometers. The inventors have found that even an intermediate structure of such a small thickness is sufficient to form antennas with suitable properties. The requirement for large distances between the base surface and the antenna surface structure is, on the other hand, counterbalanced by the desire for the smallest possible extension above the steel sheet and for simple manufacture in the fewest possible steps.Here too, the inventors have found that the values ​​mentioned are well suited to balancing these contradictory requirements.

[0045] According to some preferred embodiments, variants, or refinements of embodiments, the intermediate structure has at least two dielectric functional layers, preferably at least three dielectric functional layers. The various dielectric functional layers can be made entirely or partially of the same material or of different materials. For dielectric functional layers, lacquer is preferred as a base. The inventors have discovered that lacquer-based dielectric layers can not only be applied using known and widely available machines, but surprisingly, can also be formed with properties favorable for the antenna function of the antenna (or the retroreflector function in the case of a retroreflector).

[0046] An advantage of multilayer intermediate structures, which in particular have several dielectric functional layers based on a lacquer, is that different materials (especially lacquer types) can be used to meet different requirements and achieve different properties, for example: corrosion protection, chemical resistance, dielectric constant, dielectric losses, surface properties, temperature stability, and / or the like.

[0047] The formation (in particular: application) of several dielectric functional layers on top of one another – whether identical or different – ​​also has the advantage of reducing or eliminating the likelihood of a continuous pore forming throughout the entire intermediate structure. Such pores can promote undesired breakdowns through the intermediate structure. Furthermore, existing production lines are often equipped with machines that can only form or apply certain layers up to a maximum thickness. To achieve a desired thickness of the intermediate structure, it can therefore be advantageous to apply a dielectric functional layer of the same material and optionally also the same thickness two or more times on top of one another.

[0048] According to some preferred embodiments, variants, or refinements of embodiments, each functional layer of the intermediate structure has a thickness between approximately (or exactly) 20 micrometers and approximately (or exactly) 80 micrometers, preferably between approximately (or exactly) 30 micrometers and approximately (or exactly) 60 micrometers. The inventors have found that these values ​​allow for easy manufacturing of the intermediate structure of the steel component while simultaneously reducing the risk of through-pores.

[0049] In order to achieve a total thickness of the intermediate structure of, for example, approximately 110 micrometers to approximately 145 micrometers above the base substrate (i.e. the steel sheet), a primer layer of approximately 20 micrometers to approximately 25 micrometers in thickness can be applied, for example by means of coil coating (first dielectric functional layer of the intermediate structure), after which three further dielectric functional layers, in particular based on a lacquer, each of approximately 30 micrometers to approximately 40 micrometers are applied by means of screen printing or similar.

[0050] With a primer layer of 6 micrometers to 10 micrometers thick, an intermediate structure with four dielectric functional layers, in particular lacquer-based, each of approximately 30 micrometers to approximately 40 micrometers thick can be applied by screen printing or similar.

[0051] In other embodiments, the intermediate structure can also consist exclusively of the primer layer (or base coat). This can be applied by coil coating, for example, with a thickness d of between 80 micrometers and 100 micrometers.

[0052] According to some preferred embodiments, variants, or refinements of embodiments, the intermediate structure comprises at least one pigmented lacquer layer. The pigments can, for example, have an anti-diffusion effect, so that the pigmented lacquer layer can also be referred to as a "diffusion barrier" or "barrier layer." The pigments can, for example, be metal-based (e.g., titanium dioxide) or silicate-based. Layers with significant conductivity are less preferred in order not to impair the effectiveness of the antenna.

[0053] According to some preferred embodiments, variants, or refinements of embodiments, the structured conductive layer comprises or consists of a metal, and in particular comprises or consists of silver and / or copper (i.e., it can be formed as a silver layer, a copper layer, or a mixture of copper and silver). For example, the entire structured conductive layer can consist of silver ink, copper ink, or an ink mixed with or containing silver and copper, which is or was printed onto the intermediate structure by means of a printing process (e.g., a screen printing process or an inkjet printing process).

[0054] Furthermore, the structured conductive layer can comprise or consist of graphene and / or graphite. For example, the entire structured conductive layer can consist of graphene ink, graphite ink, or an ink mixed with or containing graphene and graphite, which is or was printed onto the intermediate structure using a printing process (e.g., a screen printing process or an inkjet printing process).

[0055] The structured conductive layer can also consist of an ink which comprises a mixture of copper, silver, graphene, and / or graphite and which is or was printed onto the intermediate structure by means of a printing process (e.g., a screen printing process or an ink jet printing process).

[0056] According to some preferred embodiments, variants, or refinements of embodiments, the structured conductive layer can be between approximately (or exactly) 1 micrometer and approximately (or exactly) 30 micrometers thick, preferably between approximately (or exactly) 3 micrometers and approximately (or exactly) 10 micrometers, for example, 8 micrometers, 9 micrometers, or 10 micrometers thick. Particularly when the structured conductive layer is a silver layer and / or a copper layer, these values ​​are particularly well suited to balancing sufficient thickness for the antenna effect or reliable electrical conductivity on the one hand, and requirements for the printing process and the maximum height of the steel component on the other.

[0057] According to some preferred embodiments, variants, or refinements of embodiments, a protective film is applied over the structured conductive layer. This is particularly advantageous if the coated steel component is also designed for cold forming. The protective film can protect the structured conductive layer from damage caused by cold forming.

[0058] According to some preferred embodiments, variants, or refinements of embodiments, the steel component comprises an antenna arrangement with a plurality of antennas and with at least one matching element in the structured conductive layer. The at least one matching element can be, for example, a combiner, a divider, and / or an impedance matching element, such as a taper or widening in an electrical line in the structured conductive layer. The plurality of antennas is formed, in particular, over the same base substrate as the base surface, with the same intermediate structure as the dielectric, and with the same structured conductive layer.

[0059] According to some preferred embodiments, variants, or refinements of embodiments, the antenna arrangement is designed as a transmitting and / or receiving arrangement. Preferably, this arrangement is or can be coupled to at least one signal amplifier and / or signal generator, which is particularly preferably also formed in or on the steel component.

[0060] According to some preferred embodiments, variants, or refinements of embodiments, the antenna arrangement is designed as an electrically closed (or: isolated) retro-reflector arrangement, in particular a radar retro-reflector arrangement. In particular, in contrast to transmit / receive arrangements, retro-reflector arrangements are thus not coupled to signal generators or signal sinks, but rather serve solely for the targeted (or: directed) reflection of incident electromagnetic radiation. For these, but also advantageously for various other applications and embodiments, the steel component according to the invention can thus be realized as a purely passive steel component, i.e., in particular, without an external power supply.

[0061] A retro-reflector arrangement can generally be understood as an arrangement designed to reflect or redirect incoming electromagnetic radiation in a defined direction. For example, the retro-reflector arrangement can be configured to reflect incoming signals precisely in the direction from which they originate. Such retro-reflector arrangements can, for example, improve radar detection of steel components, which is particularly useful when the steel component is a vehicle component, a facade component, a lamppost, or a street sign.

[0062] Alternatively, the retro-reflector arrangement could also be designed to deflect or re-emit incoming signals in directions other than the incoming direction. This could, for example, make it more difficult to detect the steel component using radar, which could be useful for military vehicles. Another application for this would be signal redirection on building facades, for example from cell phone towers on buildings down into narrow urban canyons, using steel components according to the invention as building facade components.

[0063] A retro-reflector arrangement can also be designed to redirect incoming electromagnetic radiation in precisely the direction it was received. This ensures that the steel component can be detected equally well electromagnetically from as many (or even all) directions as possible, for example, by an infrared or radar sensor.

[0064] One and the same steel component can have (at least) one transmitting arrangement, (at least) one receiving arrangement and / or (at least) one retro-reflector arrangement, each of which can be optimized for the same or for different frequency ranges.

[0065] According to some preferred embodiments, variants, or refinements of embodiments, a topcoat is applied over the structured conductive layer. The topcoat may serve to protect the structured conductive layer from external influences or damage and / or serve aesthetic purposes. Thus, the topcoat not only increases the robustness of the steel component but also its usability and design freedom.

[0066] According to some preferred embodiments, variants, or refinements of embodiments, the steel component has a curvature in the region of the antenna surface structure and / or the electrical contact line. The curvature can be designed such that sections of the steel component remote from the center of curvature exhibit an elongation of up to 15%, up to 20%, or even up to 40% compared to the planar (unformed) state of the steel component. The integrated construction of the steel component according to the invention enables non-destructive curvature of the steel component even after the formation of the intermediate structure and / or the structured conductive layer, for example, through subsequent cold forming. Thus, steel components can be manufactured with a high degree of design freedom and easily even with curved sections that simultaneously have a functioning antenna (or an antenna arrangement or at least an electrical contact line).

[0067] According to some preferred embodiments, variants, or refinements of embodiments, the area ratio of the structured conductive layer or an area framed or covered by the antenna surface structure to the area of ​​the base substrate is 1:20 or less, preferably 1:50 or less. In the case of multiple antenna surface structures, this can apply to each individual antenna surface structure, or even to all antenna surface structures together. Thus, there is a high degree of design freedom regarding where the antenna surface structure(s) can be arranged above the base substrate.

[0068] According to a further aspect, the present invention provides a steel component according to an embodiment of the first aspect of the present invention, which has been cold-formed, ie, a cold-formed steel component according to the invention. For example, it can be provided that the at least one antenna surface structure was planar before cold-forming and is non-planar in the cold-formed steel component.

[0069] The steel component, particularly the cold-formed steel component, can preferably be a vehicle part or a building facade part. Examples of vehicle parts that come into consideration are doors or roofs of vehicles such as airplanes, ships, trains, trucks, or cars. This allows, for example, the radio and / or mobile phone antenna, which is usually attached to the roof of a vehicle in the form of a flexible rod or "shark fin," to be invisibly integrated into the roof of the vehicle. Building facade parts can, for example, be cladding of building facades.

[0070] According to a further aspect, the present invention provides a method for producing a steel component, comprising the steps of: Providing an (electrically conductive) base substrate made of a coated or uncoated steel sheet; forming an intermediate structure, comprising applying at least one lacquer-based dielectric functional layer directly to the base substrate; and forming a structured conductive layer directly on the intermediate structure such that at least one antenna surface structure is formed in the structured conductive layer, which, together with the base substrate as the base surface and with the intermediate structure as the spacer, forms at least one antenna.

[0071] The method according to the invention for producing a steel component is particularly suitable for producing the steel component according to the embodiments of the first aspect of the present invention, i.e., the steel component according to the invention. Thus, the method steps of the method according to and for all described or implied variants, options, modifications, or variations of the steel component according to the invention are adaptable accordingly, and vice versa.

[0072] Providing the base substrate made of a coated steel sheet may comprise providing an uncoated steel sheet and subsequently coating the uncoated steel sheet. The coated steel sheet may, in particular, be a galvanized steel sheet, i.e., a steel sheet coated with zinc or a zinc alloy, or a steel sheet coated with aluminum or an aluminum alloy.

[0073] The application of at least the dielectric functional layer based on a lacquer directly onto the base substrate can also be referred to as a "primer coating." This can be achieved, for example, by: Coil coating, screen printing, digital printing, inkjet printing, powder coating, dipping, airbrushing and / or slot-die coating.

[0074] According to some preferred embodiments, variants, or refinements of embodiments, the intermediate structure is formed by applying a plurality of dielectric functional layers to one another. These can be formed as already discussed above, in particular from the same or different materials, with the same or different thicknesses, with the described preferred individual thicknesses and / or total thicknesses, and preferably based on a lacquer.

[0075] According to some preferred embodiments, variants or refinements of embodiments, the application of a single dielectric functional layer, in particular one or each dielectric functional layer after / on the base coat, is carried out, in particular by means of: Coil coating, screen printing, digital printing, inkjet printing, powder coating, dipping, airbrushing and / or slot-die coating.

[0076] The formation of the structured conductive layer may in particular comprise (or consist of): a) forming an unstructured conductive layer and subsequently structuring the conductive layer (for example by etching with or without an etching mask or the like); or b) applying the conductive layer in an already structured form, for example by means of a printing process.

[0077] According to some preferred embodiments, variants or refinements of embodiments, the formation of the structured conductive layer on the intermediate structure is carried out by means of: Screen printing, digital printing, inkjet printing, rotary screen printing, flexographic printing, stencil printing, and / or web printing.

[0078] As already described above, the structured conductive layer can be applied, in particular printed, to the intermediate structure using (or as a) metallic ink, preferably a silver ink. In other words, the structured conductive layer is particularly preferably formed by printing at least one structured layer of silver ink.

[0079] What is particularly advantageous in this aspect of the present invention is that the steps mentioned for producing the steel component are already used for most steel components during their manufacture and thus only minor modifications are necessary to implement the method according to the invention in an existing system.

[0080] Further preferred embodiments, variants and refinements of embodiments emerge from the subclaims and from the description with reference to the figures.

[0081] According to some preferred embodiments, variants or refinements of embodiments, the method further comprises the steps: Optionally, applying a protective film over the structured conductive layer; and cold forming at least a portion of the steel component, if necessary while the protective film is applied. The protective film can reduce or prevent damage to the antenna during forming.

[0082] According to some preferred embodiments, variants, or refinements of embodiments, during the cold forming process, among other things, a portion of the structured conductive layer is formed, which comprises at least one of the at least one antenna surface structure and / or an electrical contact line to the antenna surface structure. This results in a high degree of design freedom. Short description of the characters The invention is described below with reference to

[0083] The embodiments are explained in more detail in the figures of the drawings. They show: Fig. 1 shows a schematic cross-sectional view through a steel component according to one embodiment of the present invention; Fig. 2 shows a schematic cross-sectional view through a steel component according to a further embodiment of the present invention; Fig. 3 shows a schematic cross-sectional view through a steel component according to yet another embodiment of the present invention; Fig. 4 shows a schematic cross-sectional view through a steel component according to yet another embodiment of the present invention; Figs. 5A-5E show schematic views of possible antenna types of the antenna in steel components according to the invention; and Fig. 6 shows a schematic flow diagram for explaining a method according to a further embodiment of the present invention.

[0084] In all figures, identical or functionally identical elements and devices are used - unless otherwise stated. have been provided with the same reference symbols. The designation and numbering of the process steps does not necessarily imply a sequence, but serves to facilitate differentiation, although in some variants the sequence may also correspond to the numbering sequence. Detailed description of the characters

[0085] Fig. 1 shows a schematic cross-sectional view through a steel component 100 according to a first embodiment of the present invention. The steel component 100 comprises an electrically conductive, coated or uncoated steel sheet, for example, a galvanized steel sheet, as a base substrate 110. An intermediate structure 120 is applied directly to the base substrate 110 (more precisely: to a conductive surface of the base substrate 110).

[0086] The thickness of the base substrate 110 plays a minor role in many antenna systems, also due to the shallow penetration depth of electromagnetic waves at typical frequencies. However, in slot-type antennas, the thickness of the base substrate 110 can play a role, since in this case, slots are formed through the base substrate 110. In this case, the thickness of the base substrate can be, for example, between 0.5 mm and 1.0 mm up to 9 mm.

[0087] In the embodiment of Fig. 1 The intermediate structure 120 consists of a first dielectric functional layer 122, based on a resist, applied directly to the base substrate 110, and a second dielectric functional layer 124, preferably also based on a resist, applied directly to this first dielectric functional layer 122. The first and second dielectric functional layers 122, 124 can consist of the same resist material or have different resist materials. Possible resist types include, for example: Polyester; polyurethane (PU); polyvinyl chloride (PVC); epoxy resin; acrylate; methacrylate; and / or the like.

[0088] The term "second dielectric functional layer" is not intended to imply that this is necessarily a single functional layer, but is intended to be understood as an abstract term to distinguish it from the first dielectric functional layer 122, which is applied directly to the base substrate 110. Accordingly, there may be one or more second dielectric functional layers 124, as will be described below with reference to the Figuren 2 and 3 will be explained.

[0089] A structured conductive layer 130 is applied directly to the intermediate structure 120, on the side facing away from the base substrate 110. At least one antenna surface structure 140 is formed in the structured conductive layer 130, realized by the structuring. The antenna surface structure 140 can be formed, for example, in the form of a patch or a loop.

[0090] The patch may preferably have a square, rectangular, circular, elliptical and / or other regular or irregular shape; this also applies analogously to a metallic loop, which may be formed in the structured conductive layer 130 on the intermediate structure 120. In the following, some particularly preferred embodiments of antenna surface structures 140 will be described in more detail, in particular with reference to Fig. 5A-5E .

[0091] The antenna surface structure 140, together with the base substrate 110 as the base surface and the intermediate structure 120 as the dielectric (or spacer), forms an antenna 150. If multiple antenna surface structures 140 are formed in the structured conductive layer 130, the base substrate 110 and the intermediate structure 120 can advantageously function as the base surface and dielectric, respectively, for each of the antennas.

[0092] It is therefore also unnecessary for many applications to precisely align the structuring of the structured conductive layer 130 with respect to the base substrate 110 and all individual layers of the intermediate structure 120, since the base substrate 110 and the intermediate structure 120 are advantageously uniform in the horizontal direction, i.e. parallel to the extension of the sheet-like base substrate 110.

[0093] To form a plurality of antennas within the steel component 100, it may thus be sufficient to apply the intermediate structure 120 using simple coating processes (e.g., printing processes, dipping processes, or the like), whereby differentiation of the individual antennas 150 can be realized exclusively by a suitably structured conductive layer 130. It is thus clear how the structure of the steel component 100 according to the present invention can be manufactured in a simple manner, feasible on an industrial scale, and at the same time with a level of complexity that meets any requirement. Cutting the steel component 100 to size can then preferably be carried out precisely after the antenna 150 has been completed.

[0094] This applies in particular if the electrical contact lines of (or to) the antenna 150 are also formed in the structured conductive layer 130.

[0095] The inventors have determined that a thickness d of between approximately (or exactly) 30 µm and approximately (or exactly) 300 µm is particularly suitable for the intermediate structure 120. A thickness d of between approximately (or exactly) 110 µm and approximately (or exactly) 230 µm is particularly preferred, and particularly preferably between approximately (or exactly) 140 µm and approximately (or exactly) 200 µm.

[0096] In the embodiment according to Fig. 1 This can be achieved, for example, by a first dielectric functional layer 122 with a thickness of between 70 µm and 90 µm and a second dielectric functional layer 124 with a thickness of between 20 µm and 40 µm. The first dielectric functional layer 122 can be applied to the base substrate 110 with a thickness of between 70 µm and 90 µm, preferably between 75 µm and 85 µm, particularly preferably 80 µm, for example by means of tape coating.

[0097] The second dielectric functional layer 124 can, for example, also be formed by means of strip coating (for example with a thickness between 20 µm and 25 µm), by means of screen printing (for example with a thickness between 30 µm and 40 µm) and / or the like. As a variant of the steel component 100, two second dielectric functional layers 124 with the described thickness can also be formed, so that the thickness d of the intermediate structure 120 can then be, for example, between 110 µm and 160 µm. Another example would be a steel component 100 with a first dielectric functional layer 122 with a layer thickness of 80 µm (e.g., applied by strip coating), and with four second dielectric functional layers 124, each with a layer thickness of 35 µm (e.g., applied by screen printing), resulting in a thickness d of the intermediate structure 120 of 220 µm.

[0098] The second dielectric functional layer 124 (or one of several such) can be formed as a pigmented lacquer layer, for example as a diffusion barrier.

[0099] As in Fig. 1 As shown schematically, in particular, the first dielectric functional layer 122, which can also be referred to as a base coat or primer layer, can cover the entire base substrate 110 or at least the majority of a surface of the base substrate 110 on one side of the steel sheet, while the second dielectric functional layer 124, in contrast, can be formed with a smaller area, i.e., locally limited. This has the advantage that, in standardized processes, partially standard coated or uncoated steel sheets are first provided with a base coat before they are further processed.

[0100] In contrast, the second dielectric functional layer 124 can then be applied in a more targeted manner, conserving resources. However, it can also be provided that the second dielectric functional layer 124 covers the entire surface of the first dielectric functional layer 122 facing away from the base substrate 110. Likewise, the structured conductive layer 130 can cover the entire surface of the (possibly uppermost) second dielectric functional layer 124 facing away from the first dielectric functional layer 122, or only a portion thereof.

[0101] The structured conductive layer 130 can, in particular, comprise silver or consist of silver, although other variants and materials are also possible, as described above. In some advantageous variants, the formation of the structured conductive layer 130 can be achieved by printing the structured conductive layer 130 onto the second dielectric functional layer 124, or, in the case of multiple second dielectric functional layers 124, onto the uppermost layer thereof. Preferred methods for this are screen printing, digital printing, droplet jet printing, rotary screen printing, flexographic printing, stencil printing, or roll-to-roll processes.

[0102] In a specific embodiment, the steel component 100 can have a first dielectric functional layer 122 made of a polyester-polyurethane mixture, which has been applied to the base substrate 110 by means of a coil coating. The second dielectric functional layer 124 can be acrylate-based and screen-printed onto the first dielectric functional layer 122. Finally, the structured conductive layer 130 can be made of silver ink and screen-printed onto the intermediate structure 120.

[0103] Fig. 2 shows a schematic cross-sectional view through a steel component 200 according to a further embodiment of the present invention. The steel component 200 is a variant of the steel component 100 and differs from it in that, instead of a single second dielectric functional layer 124, a plurality of second dielectric functional layers 224-1, 224-2, 224-3, 224-4 (hereinafter referred to collectively as 224-i) are applied to the first dielectric functional layer 122.

[0104] As in Fig. 2 As can be seen, in particular (but not necessarily) four second dielectric functional layers 224-i can be provided, each of which can be made of the same material (e.g., based on acrylate), but also of different materials. The layer thickness of the individual second dielectric functional layers 224-i is advantageously substantially (or exactly) the same. The distance between the base area of ​​the antenna 150 formed by the base substrate 110 and the antenna surface structure 140 is thus the thickness d of the intermediate structure 120, formed as the sum of the four layer thicknesses of the second dielectric functional layers 224-i and the layer thickness of the first dielectric functional layer 122.If the layer thickness of the first dielectric functional layer 122 is, for example, 25 micrometers, and the layer thickness of each of the second dielectric functional layers 224-i is 30 micrometers, the resulting thickness d of the intermediate structure is 145 micrometers.

[0105] Fig. 3 shows a schematic cross-sectional view through a steel component 300 according to a further embodiment of the present invention. The steel component 300 is a variant of the steel component 200 and differs from the latter in that a topcoat 360 (i.e., a paint-based covering layer) is applied over the second dielectric functional layers 224-i, over the structured conductive layer 130, and at least over a portion of the first dielectric functional layer 122. The topcoat 360 can serve to protect the at least one antenna surface structure 140. In the design of the steel component 300, in particular of the at least one antenna 150, the electrical properties of the topcoat 360 (or: topcoat layer) are advantageously taken into account.

[0106] The topcoat 360 can, for example, also be a colored coating, such as the exterior coating of a vehicle component. The steel component 300 can thus, for example, be a vehicle component with an integrated antenna 150 (and / or with an integrated retro-reflector arrangement) on a (planned) exterior of the vehicle.

[0107] Fig. 4 shows a schematic cross-sectional view through a steel component 400 according to a further embodiment of the present invention. The steel component 400 is a variant of the steel component 100 and differs from the latter in that the steel component 400 has a curvature, at least locally. This can be characterized in that the steel component 400 has a greater elongation on its outer side 401 (i.e., the outer surface of the structured conductive layer 130 facing away from the base substrate 110) than on its inner side 402 (i.e., on the free-standing outer surface of the base substrate 110). The outer side 401 can be elongated by 10%, 20%, 25%, or even 40% compared to the inner side 402.

[0108] Alternatively, an outer radius of curvature R of the outer side 401 can also be defined to describe a local curvature of a section of the steel component 400, in particular a section that includes at least one antenna surface structure 140 and / or an antenna 150 and / or an electrical contact line. R can, for example, be between 1 mm and 10 meters. For a section that has at least one antenna surface structure 140, the outer radius of curvature R can, for example, be between 20 mm and 10 m. For a section that does not have an antenna surface structure but does have at least one electrical contact line, the outer radius of curvature can, for example, be between 1 mm and 50 mm. In general, sections with electrical contact lines but without antenna surface structures 140 can, in particular, be designed or provided with a greater curvature than sections with at least one antenna surface structure 140.

[0109] As already explained, the integrated arrangement of the steel components 100-400 according to the invention allows the steel component 100-400 to be deformed by cold forming without destroying the antenna 150 or its electrical contact lines, which provides a high degree of design freedom. The entire steel component 400 can have the aforementioned curvature, or the curvature can be present only locally, while other sections of the steel component 400 are curvature-free (r=R=infinity), or the steel component 400 can have different curvatures in different directions. The curvature or curvatures can be convex curvatures as in Fig. 4 and / or concave curvatures.

[0110] As already explained, the invention makes it possible, in particular, to provide at least one section of the steel component with a curvature, which section contains at least one antenna surface structure 140 and / or at least one antenna 150 and / or at least one electrical contact line. Such sections in particular cannot be curved using conventional techniques or cannot be provided with corresponding structures.

[0111] The steel components 100-400 according to the invention support numerous conventional cold forming processes, such as bending, edging, deep drawing, and / or the like. Depending on the selection of the materials for the intermediate structure 120 (in particular: the coating system), large degrees of deformation down to approximately 1T are possible, corresponding to bending tests in a T-bend test, i.e., for example, strain rates of up to 50%.

[0112] The antenna surface structures 140 (i.e., the radiating or receiving antenna elements) are typically applied—without limiting the generality—in regions of the base substrate 110 with a lower degree of deformation. The unevenness / curvature in the region of the at least one antenna surface structure 140 in the formed state of the base substrate 110 can be taken into account in the antenna design, for example, in a 3D finite element method (FEM) simulation. For this purpose, the antenna surface structures, which are typically printed in a planar state, are pre-distorted accordingly and then cold-formed into the desired final shape with the desired antenna parameters.

[0113] Not only the geometry, but also the potential thinning of the conductive patterned conductive layer 130 due to local deformation can be taken into account. Electrical contact lines are typically also routed in areas of greater deformation—e.g., around edges.

[0114] In some embodiments, therefore, at least one electrical contact line is arranged on a section of the steel component with a higher curvature than the curvature of a section of the steel component in the region of at least one antenna, the latter preferably being non-vanishing.

[0115] It goes without saying that not only the steel component 100 from Fig. 1 , but also the steel components 200; 300 from Fig. 2 and Fig. 3 and steel components according to any other embodiments can also be formed with one or more curvatures.

[0116] Fig. 5A-5E show schematic views of possible antenna types AE of the antenna 150 in steel components according to the invention. Accordingly, the steel components according to the invention can be designed such that at least one antenna 150 therein corresponds to one of these antenna types, wherein the antenna types in the Fig. 5A-5E are not exhaustive, but only represent a selection of possible antenna types to illustrate the feasibility using the present invention.

[0117] According to Fig. 5A the at least one antenna 150 can be designed as a grounded coplanar patch antenna A. For this purpose, the Fig. 5A The section of the structured conductive layer 130 shown is divided into two sections, which are galvanically separated from each other by a trench structure 143: on the one hand, the antenna surface structure 140 with microstrip-shaped electrical contact line 145, and on the other hand, the remaining surface 142 of the structured conductive layer 130. The remaining surface 142 is intended to be connected to ground, so that the antenna surface structure 140 in the form of a rectangular patch and the grounded remaining surface 142 are then arranged coplanarly. The base substrate 110 is also intended for grounding. The trench structure 143, where it is arranged, completely exposes the (possibly uppermost) dielectric functional layer 122, 124; 224-i from the structured conductive layer 130.

[0118] It is understood that several such antenna surface structures 140 can be arranged within the structured conductive layer 130, which can optionally also be connected (or interconnected) to form an antenna arrangement by means of the electrical contact lines 145. The remaining surface 142 that is grounded or intended for grounding can be common to all of these antenna surface structures 140.

[0119] As an example, a grounded coplanar patch antenna A with a thickness d of the intermediate structure 120 of d=180 micrometers at a permittivity ε r =4.4 with a loss factor tanδ=0.001, a -10dB bandwidth >1% and a drop of -3dB at an opening angle >40° / 80° (horizontal / vertical) can be realized.

[0120] According to Fig. 5B the at least one antenna 150 can also be designed as a patch antenna B, here with, for example, a square antenna surface structure 140 and electrical contact line 145 as a microstrip line in the structured conductive layer 130. The structured conductive layer 130 here consists of antenna surface structure(s) 140 and electrical contact line(s) 145. Here, too, it is understood that several such antenna surface structures 140 can be connected or interconnected to form an antenna arrangement via several electrical contact lines 145, or can also be individually connected to a main supply line (feed line) or main discharge line.

[0121] According to Fig. 5C The at least one antenna 150 can also be designed as a patch antenna with a coaxial electrical contact line C (here: supply line). For this purpose, a hole can be formed in the base substrate 110 or used for the coaxial electrical contact line 146.

[0122] According to Fig. 5D The at least one antenna 150 can also be designed as a patch antenna with a near-field coupled electrical contact line D (proximity feed patch antenna). For this purpose, a further structured conductive layer is formed within the intermediate structure, for example - as in Fig. 5D shown - between the first dielectric functional layer 122 and the second dielectric functional layer 124, or between several second dielectric functional layers 124.

[0123] According to Fig. 5E The at least one antenna 150 can be designed as a patch antenna with an aperture-coupled electrical contact line E (aperture-coupled feed). For this purpose, an aperture 115 (here a slot) is formed in the base substrate 110. On the side of the base substrate 110 facing away from the intermediate structure 120, a further dielectric layer 126 is arranged, on which in turn a further structured conductive layer is formed, which comprises (or consists of) an electrical contact line 145 designed as a microstrip line. A signal on this microstrip line is coupled through the aperture 115 to the antenna surface structure 140 (transmitting antenna), or a signal received by the antenna surface structure 140 is coupled via the aperture 115 to the microstrip line. The Fig. 5D und 5E The gaps shown between some layers are for illustration purposes only.

[0124] Fig. 6 shows a schematic flow diagram for explaining a method for producing a steel component, in particular a steel component according to the first aspect of the present invention, such as one of the steel components 100-400. The method is adaptable according to all options, variants, or embodiments described with regard to the steel component according to the invention, and vice versa. For better understanding, reference numerals from the preceding figures are therefore also used for the following description, without these being understood as limiting.

[0125] Possible properties of the steel component have been explained in detail above. It goes without saying that the process steps described below can be carried out in such a way that these properties are present or developed.

[0126] In a step S100, an electrically conductive base substrate 110 made of a coated or uncoated steel sheet is provided. This may include providing an uncoated steel sheet in a step S110 and coating the uncoated steel sheet in a step S120, for example, by galvanizing or aluminum coating.

[0127] In a step S200, an intermediate structure 120 is formed directly on the base substrate 110. The formation S200 of the intermediate structure 120 comprises at least one application S210 of at least one first resist-based dielectric functional layer 122 directly onto the base substrate 110. As described above, in one or more further steps S220, at least one further (second) dielectric functional layer 124; 224-i, preferably resist-based, can be formed or applied directly one above the other, namely directly on the first dielectric functional layer 122.

[0128] Each (or at least one) step of applying S210, S220 a dielectric functional layer 122, 124; 224-i, in particular a lacquer-based layer, is preferably followed by a drying step S230 before the next step S220 is performed. Drying S230 can be performed, for example, in an oven (e.g., a continuous oven), by a UV dryer, and / or the like.

[0129] The application S210, S220 of dielectric functional layers 122, 124; 224-i, in particular based on lacquer, is carried out, for example, by: Coil coating, screen printing, digital printing, inkjet printing, powder coating, dipping, airbrushing and / or slot-die coating.

[0130] In a step S300, a structured conductive layer 130 is formed directly on the intermediate structure 120 such that at least one antenna surface structure 140 is formed in the structured conductive layer 130, which, together with the base substrate 110 as a base surface and with the intermediate structure 120 as a dielectric (or spacer), forms at least one antenna 150.

[0131] The formation S300 of the structured conductive layer 130 may, for example, comprise forming the structured conductive layer by applying, in particular by means of a printing process (e.g., a screen printing process, a digital printing process, a droplet jet printing process, a rotary screen printing process, a flexographic printing process, or a roll process), the conductive layer already in the structured state.

[0132] The formation S300 of the structured conductive layer 130 may preferably comprise or consist of printing at least one structured layer of silver ink.

[0133] In other embodiments, however, the formation of the structured conductive layer 130 may comprise a formation S310 (e.g., application) of an unstructured conductive layer and a subsequent structuring S320 of the formed (or applied) unstructured conductive layer.

[0134] Depending on the realized design of the antenna 150, one or more electrical contact lines 145, 146 are also formed in (or between) steps S100, S200. Electrical contact lines 145, 146 (or parts thereof) in the structured conductive layer 130 are preferably formed in step S300. Electrical contact lines 145, 146 that run through or within the intermediate structure 120 can be formed in additional steps, for example, for antenna type D from Fig. 5D .

[0135] After forming S200 the intermediate structure 120 and the structured conductive layer 130, cold forming S500 can optionally be performed. As already described above, the structures 110, 120, 130, 150, etc., can be formed in steps S100-S300 such that they only achieve the necessary properties for their intended use once cold forming S500 has been performed.

[0136] The intermediate structure 120 and / or the structured conductive layer 130 can comprise electrical contact lines, such as supply or discharge lines for the at least one antenna 150, or connecting lines between multiple antennas 150 of an antenna arrangement. The formation of at least one electrical contact line can thus take place in one of steps S200 or S300, or also be performed in an additional step. The steel component according to the invention has the advantageous property that curvatures can also be realized in the region of the antenna surface structure(s) 140 and / or the electrical contact line(s) 145, 146. Since this allows for particular design freedom, the cold forming S500 is thus preferably carried out such that a curvature is created in the region of at least one antenna surface structure 140 and / or at least one electrical contact line 145, 146, for example, with the curvature characteristics described above.

[0137] The method may include an optional step S10 of simulating the antenna 150 to be manufactured and / or the steel component 100-400 to be manufactured. The simulation S10 may include receiving desired properties (in particular reception and / or transmission properties) of the antenna 150 to be manufactured, properties of the formed steel component 100-400, the cold forming S500 itself, and / or the non-formed base substrate 110, or the like. It can then be automatically simulated (or determined) with which properties the method steps, in particular the method steps S200 and S300, must be performed so that an antenna 150 with the desired properties is present after the cold forming S500.

[0138] In other words, in the simulation S10, a pre-distorted design can be simulated (or determined) such that a steel component manufactured according to this pre-distorted design exhibits the desired properties after its forming S500. The simulation S10 can be performed using a computer system and thus be computer-implemented. For example, the finally formed antenna 150 can be designed as a 3D component in an FEM tool and optimized according to the required functional properties. This 3D component is then transformed to the planar state, taking the forming process into account, whereby changes in the material such as thickness variations, strains, thinning of printed structures, etc., can be taken into account.

[0139] The desired properties can vary depending on the application. Typical relevant optimization parameters, i.e., required functional properties for antennas, can include: Antenna gain, directivity, center frequency and bandwidth, antenna impedance and / or polarization type and polarization planes.

[0140] For the design and optimization of antennas using resist-based coatings, it is advantageous to have as precise a knowledge as possible of the resist properties, especially the dielectric constant and the loss factor at the desired antenna frequency. Also advantageous is the most precise knowledge possible (and, if necessary, adjustment) of the conductivity of the structured conductive layer.

[0141] Typically, these parameters are not specified by coating manufacturers at all, or only in the very low-frequency range. For a given coating structure, these parameters can therefore be determined in a first step by manufacturing and measuring test structures. Suitable test structures are known from the state of the art (e.g., resonators, lines, etc.). The determined parameters can then be used to design the antenna structure. It is also conceivable to print such test structures as part of the regular production process. This allows the production process to be monitored continuously or randomly.

[0142] It can be provided that the method steps of the method, in particular steps S200 and S300, are carried out in such a way, and in particular generate structures with such properties and geometric dimensions and shapes that the simulated pre-distorted design is realized.

[0143] Likewise, additional steps may be performed to form the antenna 150. For slot-type antennas (such as type E in Fig. 5E For example, apertures (slots or recesses) can be formed in the base substrate 110, e.g., punched therein. This occurs before or after the application S210 of the first dielectric functional layer 122. Punching can also occur after or during the formation S200 of the remaining intermediate structure 120, for example, before or after the application S220 of a second dielectric functional layer 124 (possibly one of several).

[0144] In order to protect in particular the at least one antenna 150, after the formation S300 of the structured conductive layer 130, a protective film can be applied or formed on the structured conductive layer 130 in a step S400, which can be removed again in a step S600 after the cold forming S500.

[0145] Optionally, a topcoat 360 can also be applied in a step S700, for example, before (or instead of) applying the protective film S400, or after removing the protective film S600 after cold forming S500. The topcoat 360 can be applied using any of the coating methods described or known in the art, for example, by powder coating. If step S10 is performed, the properties of the topcoat 360 are advantageously taken into account in the simulation.

[0146] The method may include further method steps that can be performed before, during, after, or between the described method steps. These steps may include, for example, cutting, applying additional substrate layers, drying layers (e.g., the structured conductive layer 130), testing conductive structures, applying and subsequently detaching a temporary protective layer, performing a final test of the antenna 150, and / or the like. List of reference symbols

[0147] 100Steel component 110Base substrate 115Aperture 120Intermediate structure 122First dielectric functional layer 124Second dielectric functional layer 126Dielectric functional layer 130Structured conductive layer 140Antenna surface structure 142Remaining surface 143Trench structure 145Electrical contact line 146Coaxial electrical contact line 150Antenna 200Steel component 224-iFunctional layer 300Steel component 360Top coat 400Steel component 401Outside 402Inside A-EAntenna types ROuter radius S10..S700Process steps

Claims

1. A steel component (100; 200; 300; 400), comprising: a base substrate (110) made of a coated or uncoated steel sheet; an intermediate structure (120) comprising at least one lacquer-based dielectric functional layer (122) applied directly to the base substrate; and at least one structured conductive layer (130) applied to the intermediate structure (120), in which at least one antenna surface structure (140) is formed, which, together with the base substrate (110) as the base surface and with the intermediate structure (120) as the dielectric, forms at least one antenna (150).

2. Steel component (100; 200; 300; 400) according to claim 1, wherein the at least one antenna (150) is designed as a patch antenna (B), in particular as a grounded coplanar patch antenna (A), as a slotted patch antenna, as a slot antenna, as a folded monopole antenna, as a loop antenna, as a folded loop antenna or as a planar inverted F antenna.

3. The steel component (100; 200; 300; 400) according to claim 2, wherein the at least one antenna (150) is designed as a grounded coplanar patch antenna (A), in that the at least one antenna surface structure (140) is at least partially surrounded by a grounded surface structure (142) of the structured conductive layer (130) through a trench structure (143) left open in the structured conductive layer (130).

3. The steel component (100; 200; 300; 400) according to claim 1 or 2, wherein an electrical contact line (145; 146) to the at least one planar antenna surface structure (140) is formed in the intermediate structure (120) and / or the structured conductive layer (130).

4. Steel component (100; 200; 300; 400) according to one of claims 1 to 3, wherein the intermediate structure (120) has a thickness of between 30 micrometers and 300 micrometers, preferably between 110 micrometers and 230 micrometers, particularly preferably between 140 micrometers and 200 micrometers.

5. Steel component (100; 200; 300; 400) according to one of claims 1 to 4, wherein the intermediate structure (120) has at least two dielectric functional layers (122, 124; 224-i) which consist of the same or different materials.

6. Steel component (100; 200; 300; 400) according to one of claims 1 to 5, wherein the structured conductive layer (130) comprises silver, copper, graphene and / or graphite and / or is between 1 micrometer and 30 micrometers, in particular 3 micrometers to 10 micrometers thick.

7. Steel component (100; 200; 300; 400) according to one of claims 1 to 6, comprising an antenna arrangement with a plurality of antennas (150) and with at least one matching element, in particular a combiner, a switch and / or an impedance matching element, in the structured conductive layer.

8. Steel component (100; 200; 300; 400) according to claim 7, wherein the antenna arrangement is designed as a transmitting and / or receiving arrangement and is coupleable to at least one signal amplifier and / or signal generator; or wherein the antenna arrangement is designed as an electrically sealed retro-reflector arrangement.

9. Steel component (100; 200; 300; 400) according to one of claims 1 to 8, wherein an area ratio of an area framed or covered by the antenna surface structure (140) to the area of ​​the base substrate (110) is 1:20 or less, preferably 1:50 or less.

10. Cold-formed steel component (100; 200; 300; 400) according to one of claims 1 to 9.

11. A method for producing a steel component (100; 200; 300; 400), comprising the steps of: providing (S100) a base substrate (110) made of a coated or uncoated steel sheet; forming (S200) an intermediate structure (120), comprising applying (S210, S220) at least one lacquer-based dielectric functional layer (122, 124; 224-i) directly to the base substrate (110); and forming (S300) a structured conductive layer (130) directly on the intermediate structure (120) such that at least one antenna surface structure (140) is formed in the structured conductive layer (130), which, together with the base substrate (110) as a base surface and with the intermediate structure (120) as a spacer, forms at least one antenna (150).

12. The method according to claim 11, wherein the formation (S200) of the intermediate structure is carried out by applying (S210; S220) a plurality of functional layers one on top of the other, in particular by means of a screen printing process, a digital printing process, a droplet jet printing process, a powder coating process, a dipping process, a spraying process, and / or a slot nozzle process.

13. The method according to claim 11 or 12, wherein the formation (S300) of the structured conductive layer (130) is carried out by printing, in particular by means of a screen printing process, a digital printing process, a droplet jet printing process.

14. The method according to claim 13, wherein the formation (S300) of the structured conductive layer (130) is carried out by printing at least one structured layer of ink, wherein the ink comprises or consists of silver, copper, graphene and / or graphite.

15. The method according to any one of claims 11 to 14, wherein the lacquer-based dielectric functional layer (122) to be applied directly to the base substrate (110) of the intermediate structure (120) is applied by means of a strip coating technique.

16. The method according to any one of claims 11 to 15, further comprising: cold forming (S500) at least a part of the steel component (100; 200; 300; 400), wherein during the cold forming (S500) among other things a section of the structured conductive layer (130) is formed, which comprises at least one of the at least one antenna surface structure (140) and / or at least one electrical contact line (145; 146).

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