High-frequency component

Abstract

The present invention relates to a high-frequency component which has at least one region which is suitable and intended for conducting and / or emitting high-frequency signals, wherein the region has a main body and a metal coating covering the main body, wherein the main body forms the shape-giving structure of the high-frequency component and has one or more walls with a wall thickness which is less than or equal to 5 mm, and / or has a grid-like structure and / or which has a plurality of perforations, wherein the ratio t / d is greater than or equal to 10 / 500, wherein t is the layer thickness of the metal layer in the cross-section and d is the largest cross-section extent of the main body in the cross-section, and / or the ratio of the mass of the metal coating to the mass of the main body is greater than or equal to 1, and / or the surface area ratio in cross-section between the metal coating and the main body is greater than or equal to 0.025.

Description

[0001] High-frequency component

[0002] The present invention relates to a high-frequency component having at least one region suitable and intended for conducting and / or emitting high-frequency signals, wherein the region has a base body and a metallic coating covering the base body.

[0003] Such RF components (hereinafter also referred to as "components") are well known. Common RF components are 3D printed and metallized. The design is exclusively focused on achieving the desired RF properties and the manufacturability of the components. Aspects of resistance to common stress tests for later use, for example, in the automotive sector, are not considered in the design of the base body.

[0004] In known RF components, the geometric design of areas that are less or not relevant for high-frequency transmission or radiation is also not considered with regard to optimization for stress tests. It is known that the expansion coefficients of 3D-printed plastic and the typical metals used in metallization differ significantly, i.e. by factors. It is also known that, according to the current state of the art, there is a trade-off between the heat deflection temperature of the materials (especially photopolymers) and their brittleness. This means that temperature-resistant materials have a significantly lower coefficient of elongation at break. This results in several disadvantages. For example, typical drop and vibration tests may not be passed even with metallization. Furthermore, post-processing is significantly more complex and cost-intensive, as brittleness leads to a high reject rate.

[0005] Furthermore, more brittle 3D printing materials lead to poorer printing results, resulting in significant limitations, especially for RF components used in frequency ranges above 50 GHz. Similar considerations apply to the glass transition temperature and melting temperature. The limitations of 3D printing materials known from the state of the art lead to the following adverse implications of RF components:

[0006] • The metallization is applied at a specific temperature or expansion of the plastic body. Higher or lower temperatures lead to different expansions of the materials, resulting in cracks and microcracks. Visible cracks are a rejection criterion during visual inspection of the components. Even more serious, however, is that cracks and barely visible microcracks significantly impair the RF properties and are therefore also a rejection criterion.

[0007] • Deformation during rapid temperature changes from high to cold temperatures: If a component is changed from, for example, 125 °C to -40 °C with a typical transition time of one minute, the outer metallization and the plastic core adapt to the new temperatures at different rates. This means that the metallization cools down quickly due to its high thermal conductivity and thus more quickly assumes the expansion dimensions associated with the temperature. The core underneath, however, is still soft (low heat distortion temperature) and, due to the high temperature, expands several times greater than the metallization. This gives rise to two types of defects. Firstly, cracks and microcracks develop. Visible cracks are a rejection criterion during visual inspection of the components.Even more serious, however, is that cracks and barely visible microcracks significantly impair the RF properties and are therefore also a rejection criterion. Furthermore, the soft core is easily deformed by the resulting stresses from the deforming metallization. This also leads to significant changes in the RF properties. Tests have shown that even a single temperature change can render RF components completely unusable, even though visual inspection reveals no defects.

[0008] If you want to adapt the plastic in such a way that it has a lower coefficient of expansion and / or a higher heat resistance, this leads to reduced printing results, brittleness and higher costs, which is a disadvantage especially for large series or quantities.

[0009] The present invention is therefore based on the object of providing an RF component that is of high quality, can be manufactured cost-effectively and has excellent RF performance, resistance to thermal shocks and resistance to mechanical stresses such as vibrations or a drop test.

[0010] This object is achieved by a high-frequency component (also called “HF component” in the context of the invention) with the features of claim 1. According to this, the base body forms the shaping structure of the high-frequency component and has a grid-like structure which has a plurality of openings, wherein

[0011] • the ratio t / d is greater than or equal to 10 / 500, where t is the layer thickness of the metallic coating in the cross-section and d is the largest cross-sectional dimension of the base body in the cross-section, and / or

[0012] • the ratio of the mass of the metallic coating to the mass of the base body is greater than or equal to 1, and / or

[0013] • the area ratio in the cross section between the metallic coating and the base body is greater than or equal to 0.025.

[0014] The cross-section through a coated lattice strut has a structure in which a metal surface of layer thickness "t" encloses at least one shaping structure of diameter "d" (or dimension "d" if the base area is rectangular). Consequently, the resulting wall thickness w = d + 2*t, if the metal layer is added on both sides (outside and inside). Preferably, the cross-section is that of a cut surface perpendicular to the extension of a lattice strut.

[0015] Alternatively or additionally, the mass ratio of metal to framework material is greater than 1:1. In other words, in the considered area of ​​the RF component, there is more, i.e. a greater mass of metal in the form of the metallic coating than the mass of the base body, which preferably consists of plastic or comprises plastic.

[0016] Alternatively or additionally, the area ratio of the cross-section in the smallest spatial dimension between metal and plastic is greater than 0.025. Thus, if a cross-sectional area is viewed perpendicular to the extension of a lattice strut, two surface areas are present: the surface of the metallic coating, and the surface of the base body. According to this feature, this area ratio is greater than 0.025.

[0017] The inventive design of the RF component enables for the first time the combination of all relevant aspects (especially for 3D-printed, coated plastic bodies): high-quality and cost-efficient manufacturing and excellent RF performance and resistance to thermal shocks (e.g.: 125°C to -40°C with 1 min transition time) and resistance to mechanical loads such as vibration (e.g.: 20g in the range 10 Hz to 2kHz or comparable from the MIL-STD-202G test) or a drop test.

[0018] According to the state of the art, it was at best possible to fulfil a selected property separately, for example: using high-temperature-resistant plastics, resistance to slow temperature cycles may be achieved, but then the mechanical strength and thermal shock resistance are inadequate and the production is unreliable.

[0019] The present invention provides an RF component in which the properties of the RF component are dominated by the properties of the metal. The base body only needs to have shaping properties. The base body is only provided where it is necessary for the high-frequency or mechanical properties. This results in cost savings in two respects: a cheaper plastic or a more cost-effective material can be used, and less plastic or material can / must be used for the base body than is known from the prior art.

[0020] The base body, which may be a plastic lattice, serves merely as a shaping framework. Lattice struts are therefore manufactured as thin as technically possible / reasonable, because the base frame only needs to survive production and plays no or only a minor technical role after production.

[0021] The RF components according to the invention are robust additively manufactured products. Robust refers to their technical usability and, in particular, their resistance to various environmental influences, such as thermal shock, continuous thermal exposure, vibration, shock, and other mechanical stresses.

[0022] It is preferably provided that the metallic coating completely covers the base body in the region, ie the base body is completely covered in the region, ie covered on all sides by a metallic coating.

[0023] In the range in question, the ratio t / d is greater than or equal to 10 / 500 and preferably greater than or equal to 20 / 500 and in particular greater than or equal to 30 / 500 and / or that the ratio of the mass of the metallic coating to the mass of the base body is greater than or equal to 1 and preferably greater than or equal to 2 and in particular greater than or equal to 3 and / or that the area ratio in the cross section is greater than or equal to 2.5% and preferably 10%.

[0024] In a further embodiment of the invention, it is provided that in the region at least 20%, preferably at least 40% and in particular at least 70% of the cross-sectional dimensions of the base body in the smallest spatial extent are less than or equal to 5 mm, preferably less than or equal to 2 mm and in particular less than or equal to 1 mm.

[0025] Furthermore, it can be provided that the base body has perforations in a volume fraction of at least 10%, preferably at least 15%, and in particular at least 25%, each provided with a tolerance of ± 2.5%. It is preferred if the base body has a monolithic structure and / or is produced by an additive manufacturing process, in particular by 3D printing. The perforations and the lattice-like structure already represent a component of the additively manufactured model and do not need to be introduced subsequently. However, it is nevertheless conceivable according to the invention for these to be introduced or added subsequently.

[0026] In this area, the base body has a lattice-like structure at least in some areas.

[0027] The aforementioned region may encompass the entire component or a portion thereof. The invention thus also encompasses an RF component that has one or more regions in which the properties according to the invention are not present.

[0028] The RF component may be, for example, a waveguide, coupler, reflector, antenna and / or antenna array or a combination of two or more of the aforementioned components.

[0029] The material of the base body in the area is preferably a plastic, in particular a material that contains or consists of one or more plastics from the following group: polyamide, urethane or acrylate.

[0030] The metallic coating in the region may have been applied using one or more of the following techniques: i. by means of a galvanic process, in particular by nickel electroplating or copper electroplating, ii. by means of an electroless chemical plating process, iii. by means of a dipping process, preferably by dipping in a dispersion containing micro- or nanoparticles, iv. by means of CVD or PVD.

[0031] A combination of the aforementioned techniques is also conceivable and encompassed by the invention.

[0032] Preferably, the component is suitable and intended to operate or be used in a frequency range above 50 GHz.

[0033] The metallic coating can be applied in single or multi-layer form. Especially when layered systems are used, the deposited metal surface can also be robust against oxidation, moisture, etc., and even suitable for use in corrosive environments. This can be achieved, in particular, by applying nickel as the final surface using electroless plating or, more specifically, electroplating (i.e., using current-driven wet chemical deposition).

[0034] It is therefore conceivable that the metallic coating in this area is oxidation-resistant and / or moisture-resistant and / or corrosion-resistant.

[0035] It is conceivable according to the invention that the metallic coating is constructed from particularly ductile materials, such as copper, in order to follow the deformation (expansion / shrinkage / softening) of the plastic to a certain extent without directly forming cracks.

[0036] However, it is also conceivable according to the invention for the metallic layer to be constructed from less ductile materials (e.g., nickel), so that the metallic layer prevents deformation of the plastic. In this case, it is particularly provided that a certain thickness of the metal is created relative to that of the plastic in order to generate the necessary force to effectively counteract the deformation force of the plastic. In a further embodiment of the invention, the component is temperature-resistant in a temperature range between -40°C and +125°C without cracks and microcracks developing.

[0037] The present invention further relates to the use of an RF component according to one of claims 1 to 15, wherein the component is used in an RF application.

[0038] The use may include the use of the RF component as a waveguide, coupler, reflector, antenna and / or antenna array.

[0039] It should be noted here that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this is a possible interpretation, but can also refer to a plurality of the elements. Likewise, the use of the plural also includes the presence of the element in question in the singular, and conversely, the singular also encompasses several of the elements in question.

[0040] Furthermore, all features of the invention described herein may be combined with one another in any way or claimed in isolation from one another.

[0041] Further details and advantages of the invention are explained in more detail using an embodiment described below.

[0042] The embodiment relates to an RF component that is used for conducting and / or radiating RF waves in the frequency range above 50 GHz.

[0043] The RF component, for example, has a grid-like base body. The base body is made of plastic and is 3D-printed. It is monolithic. The grid forms the shaping wall of the RF component, which can, for example, comprise a waveguide channel and a waveguide slot antenna. Accordingly, said grid-like, shaping, monolithic wall also contains the radiating slots of the waveguide slot antenna.

[0044] After the base body has been manufactured, a metallic coating is applied to it, preferably in such a way that the metallic coating covers the base body on all sides, i.e. the base body has no surface in contact with the ambient atmosphere, at least in the functionally relevant areas and preferably at all.

[0045] The metallic coating is applied, for example, using a multi-stage dipping process, which may in particular include galvanic deposition. In this exemplary embodiment, the metallic coating is applied in a thickness such that the ratio of t / d is greater than or equal to 40 / 500. If one considers a cross-section through a lattice strut, the cross-section results in a material thickness t of the metallic coating and a material thickness d of the plastic. The ratio of the two values ​​t and d is equal to or greater than 0.08, meaning that a large amount of metal is applied in relation to the base body. This results in an area ratio of metal surface to plastic surface in the cross-section of a lattice strut of greater than or equal to 0.3.

[0046] This has the advantage that the properties of the RF component are essentially dominated by the metal of the coating and not by the plastic of the base body. The latter serves only as a shaping element to which the coating is applied. The RF component is robust, meaning it is resistant to thermal shock, continuous thermal stress, vibration, impact, and other mechanical stresses.

Claims

Patent claims 1. High-frequency component, which has at least one region which is suitable and intended for conducting and / or emitting high-frequency signals, wherein the region has a base body and a metallic coating covering the base body, characterized in that the base body forms the shaping structure of the high-frequency component and has one or more walls with a wall thickness which is less than or equal to 5 mm and / or has a grid-like structure and / or has a plurality of openings, wherein • the ratio t / d is greater than or equal to 10 / 500, where t is the layer thickness of the metallic coating in the cross-section and d is the largest cross-sectional dimension of the base body in the cross-section, and / or • the ratio of the mass of the metallic coating to the mass of the base body is greater than or equal to 1, and / or • the area ratio in the cross section between the metallic coating and the base body is greater than or equal to 0.

025.

2. Component according to claim 1, characterized in that the metallic coating in the region completely covers the base body and / or the lattice struts of the lattice-like structure in the region are completely encompassed by the metallic coating.

3. Component according to claim 1 or 2, characterized in that in the region the ratio t / d is greater than or equal to 30 / 500 and preferably 40 / 500 and / or that the ratio of the mass of the metallic coating to the mass of the base body is greater than or equal to 2 and / or that the area ratio in the cross section is greater than or equal to 2.5% and preferably greater than or equal to 10%.

4. Component according to one of the preceding claims, characterized in that in the region at least 20%, preferably at least 40% and in particular at least 70% of the cross-sectional dimensions of the base body in the smallest spatial extent are less than or equal to 5 mm, preferably less than or equal to 2 mm and in particular less than or equal to 1 mm.

5. Component according to one of the preceding claims, characterized in that the base body has openings in the region in a volume fraction of at least 10%, preferably at least 15% and in particular at least 25% ± 2.5%.

6. Component according to one of the preceding claims, characterized in that the base body has a monolithic structure in the region and / or is produced by an additive manufacturing process, in particular by 3D printing.

7. Component according to one of the preceding claims, characterized in that the wall thickness of the wall of the base body is less than or equal to 2 mm and in particular less than or equal to 1 mm.

8. Component according to one of the preceding claims, characterized in that in the area of ​​the base body at least partially has a lattice-like structure with longitudinal struts and with transverse struts connecting them.

9. Component according to one of the preceding claims, characterized in that the region comprises the entire component or a part thereof.

10. Component according to one of the preceding claims, characterized in that the component is a waveguide, coupler, reflector, an antenna and / or an antenna array or a combination of two or more of the aforementioned components or a part of one of the aforementioned components.

11. Component according to one of the preceding claims, characterized in that the material of the base body in the region is a plastic, in particular a material which contains one or more plastics from the following group: polyamide, urethane or acrylate.

12. Component according to one of the preceding claims, characterized in that the metallic coating in the region is applied by means of one or more of the following techniques: i. by means of a galvanic process, in particular by nickel electroplating or copper electroplating, ii. by means of an electroless chemical coating process, iii. by means of a dipping process, in particular by dipping in a dispersion containing micro- or nanoparticles, iv. by means of CVD or PVD.

13. Component according to one of the preceding claims, characterized in that the component is suitable and intended to operate in a frequency range above 50 GHz.

14. Component according to one of the preceding claims, characterized in that the metallic coating in the region is designed in one or more layers.

15. Component according to one of the preceding claims, characterized in that the metallic coating in the region is oxidation-resistant and / or moisture-resistant and / or corrosion-resistant.

16. Component according to one of the preceding claims, characterized in that the component is temperature-resistant in the region between - 40 °C and + 125 °C without cracks and microcracks occurring.

17. Use of an RF component according to one of claims 1 to 16, characterized in that the component is used in an RF application.

18. Use according to claim 17, characterized in that the component is used as a waveguide, coupler, reflector, antenna and / or antenna array.