Antenna assembly for vehicle and roof assembly for vehicle

Abstract

The present disclosure relates to an antenna assembly (14) for a vehicle. The antenna assembly (14) includes at least three tapered slot antennas (22). Each tapered slot antenna (22) includes a plate-shaped conductor (34) and a tapered slot (28) extending in the plate-shaped conductor (34). Each tapered slot (28) extends along a slot direction (30), where all slot directions (30) are oriented substantially towards a center point (26) of the antenna assembly (14), and all tapered slots (28) taper towards the center point (26). The groove direction (30) is distributed with respect to a circumference extending around a center point (26). Furthermore, a roof assembly for a vehicle is shown. A roof assembly comprises a carrier layer and at least one such antenna assembly (14). The at least one antenna assembly (14) is arranged on the carrier layer.

Description

Technical Field

[0001] The present disclosure relates to an antenna assembly for a vehicle.

[0002] Furthermore, the present disclosure relates to a roof assembly for a vehicle, the roof assembly including the antenna assembly. Background Art

[0003] Modern vehicles can be connected to wireless services such as AM / FM radio, Digital Audio Broadcasting (DAB), Global Navigation Satellite System (GNSS), Remote Keyless Entry (RKE), tire pressure monitoring system (TPMS), Electronic Toll Collection (ETC), cellular connectivity (Long Term Evolution (LTE), 4G, 5G), Bluetooth, Wi-Fi, and V2X communication. Thus, functions such as infotainment, access control, communication, positioning, and security can be provided to the users of the vehicle.

[0004] For each of these services, one or more antennas are required to transmit and / or receive the corresponding signals from or at the vehicle. Thus, a certain number of antennas may need to be installed in modern vehicles. In this case, it is known to provide at least some of the antennas in a module commonly referred to as a "shark-fin" (i.e., a module including an antenna disposed on the roof of the vehicle). However, there are still challenges in the packaging of multiple antennas in a vehicle. Summary of the Invention

[0005] An object of the present disclosure is to solve or at least mitigate this challenge.

[0006] This problem is at least partially solved or mitigated by the subject matter of the independent claims of the present disclosure, where additional examples are incorporated in the dependent claims.

[0007] According to a first aspect, an antenna assembly for a vehicle is provided. The antenna assembly includes at least three conical slot antennas. Each of the conical slot antennas includes a plate-shaped conductor and a conical slot extending in the plate-shaped conductor. Each of the conical slots extends along a slot direction. All the slot directions are substantially oriented towards the center point of the antenna assembly, and all the conical slots taper towards the center point. The slot directions are distributed relative to a circumference extending around the center point. In other words, the conical slot antennas are arranged in a star shape, where the wide ends of the slots represent the tips of the star. In this case, the fact that the slot directions are substantially oriented towards the center point of the antenna assembly means that the slot directions are oriented towards the center point of the antenna assembly or towards a position close to the center point, for example, at a maximum distance of 0.03 times the maximum wavelength of the bandwidth of the antenna assembly or at a maximum distance of 15 millimeters (mm). Although a single conical slot antenna among the conical slot antennas has a so-called endfire radiation pattern, i.e., a unidirectional pattern where the main lobe appears at one end, the antenna assembly (i.e., the combination of at least three such conical slot antennas) achieves a multi-directional or omnidirectional pattern. This is useful for applications in a vehicle because the position and orientation of the vehicle relative to a transmitter or receiver far from the vehicle typically change during the use of the vehicle. At the same time, the conical slot antennas have broadband characteristics. This means that the conical slot antennas can operate with substantially or exactly the same operating characteristics within a very wide frequency or wavelength range. These frequencies or wavelengths can be defined by an associated bandpass filter. Therefore, the antenna assembly including at least three conical slot antennas provides both a multi-directional or omnidirectional radiation pattern and broadband characteristics. In addition, the single conical slot antenna and the assembly of conical slot antennas provide good impedance matching capabilities. This helps to integrate the antenna assembly into the vehicle from an electrical perspective. This is especially the case if the antenna is to be integrated into the roof assembly of the vehicle, where the roof assembly can include glass material. It is generally difficult to perform impedance matching in an environment with a relatively high dielectric constant such as glass. In other words, known antennas typically designed to operate in a low dielectric constant environment cannot provide good radiation performance in a high dielectric constant environment. This may result in relatively low radiation efficiency and / or relatively low gain. In contrast, the antenna assembly according to the present disclosure can be well adapted to such an environment, such that high radiation performance can be achieved. This can result in relatively high radiation efficiency and / or achieving the desired radiation pattern, such as high gain. At the same time, the size of such an antenna assembly is compact. First, this applies to the direction perpendicular to the plane of the plate-shaped conductor. In other words, such an antenna assembly has a relatively small height or is relatively flat. This remains the case even if the antenna assembly is slightly bent or folded due to being integrated into a slightly curved or bent part of the vehicle (such as the roof assembly of the vehicle). In addition, the dimension of the antenna assembly within the plane defined by the plate-shaped conductor is smaller than the wavelength at which the antenna assembly operates. In addition to this, this may be positively affected by a high dielectric constant environment (such as glass material).More precisely, the dimensions of the antenna assembly located in the plane defined by the plate-shaped conductor are smaller compared to the center wavelength and / or compared to the maximum wavelength at which the antenna assembly operates. This provides the possibility of integrating such an antenna assembly into a vehicle in a way that improves aerodynamics and / or aesthetics compared to known ways of integrating antenna assemblies (such as shark fins). In addition, such an antenna assembly is simple from a structural point of view. This also has the effect that the antenna assembly can be produced in a relatively simple and efficient manner.

[0008] In one example, the slot directions are evenly distributed relative to the circumference extending around the center point. In this case, an even distribution means that the angular distance between each pair of adjacent slot directions is constant over the antenna assembly. In this case, the radiation pattern of the antenna assembly is particularly uniform.

[0009] According to one example, the antenna assembly is configured as a cellular antenna assembly. This means that the antenna assembly covers frequencies from 617 MHz to 5 GHz corresponding to all sub-6G cellular bands. Therefore, a fractional bandwidth of 155% is required. In this context, the bandwidth defines the range of frequencies or wavelengths over which the antenna assembly can operate with substantially or exactly the same operating characteristics. In this context, the operating characteristics can be described by one or more performance metrics. If one or more performance metrics are below or above a predefined threshold, the operating characteristics are substantially or exactly the same. Examples of performance metrics include radiation efficiency, directivity (e.g., 3 dB from the maximum), and reflection coefficient. The bandwidth can correspond to the passband of a bandpass filter that forms part of the antenna assembly or that can be connected to the antenna assembly.

[0010] Note that sometimes a tapered slot antenna is also referred to as a Vivaldi antenna. In the following, the two terms will be used as synonyms.

[0011] According to one example, all tapered slots are bounded by the convex curved edges of the respective plate-shaped conductor. In this case, the edge protrudes towards the associated slot, i.e., the edge bulges towards the interior of the associated slot. In one example, the edge can be defined by an exponential function, such as e^ax, where a is a constant ranging from 0.08 to 0.15. Such a tapered slot antenna has a favorable radiation pattern and bandwidth.

[0012] According to one example, each of the tapered slots has a widest slot width. The widest slot widths of the tapered slot antennas adjacent to each other are directly adjacent to each other. This means that the adjacent ends of the widths of the adjacent slots are in close proximity to each other at the corresponding positions of the widest slot width. According to one example, all the tapered slot antennas (i.e., all the conductors forming the tapered slot antennas) are located in the same plane. This configuration has the following effect: The tapered slot antennas are arranged in a geometrically efficient manner, that is, a relatively high number of tapered slot antennas can be arranged in a relatively small area. In other words, the antenna assembly is very compact. From an electrical perspective, it is also advantageous to have a relatively high number of tapered slot antennas in a relatively small area, because a high number of tapered slot antennas results in an enhanced radiation pattern with fewer nulls in a higher frequency band.

[0013] In one example, each of the tapered slots has a widest slot width. The widest slot width corresponds to 0.05 times to 0.15 times the maximum wavelength of the bandwidth of the antenna assembly. According to one example, the widest slot width corresponds to 0.06 times to 0.13 times the maximum wavelength of the bandwidth of the antenna assembly. Therefore, the tapered slots are small compared to the maximum wavelength. In this context, it has been mentioned that generally, the widest slot width of a tapered slot antenna corresponds to approximately half of the maximum wavelength of the antenna bandwidth. In an example where the antenna assembly is configured as a cellular antenna assembly, the widest slot width can be 21 mm to 64 mm. In one example, the widest slot width can be 35 mm to 55 mm, particularly 40 mm to 50 mm. In another specific example, the widest slot width is 44 mm. All in all, the tapered slots and thus the antenna assembly are very compact.

[0014] According to one example, each of the tapered slots has a slot length. The slot length corresponds to 0.1 times to 0.2 times the maximum wavelength of the bandwidth of the antenna assembly. According to one example, the slot length corresponds to 0.11 times to 0.18 times the maximum wavelength of the bandwidth of the antenna assembly. In this case, the slot length can be measured as the distance between two opposite ends of the tapered slot. One of the two opposite ends can be designated as the narrow end of the tapered slot, and the corresponding other of the two opposite ends can be designated as the wide end of the tapered slot. Therefore, the tapered slots are small compared to the maximum wavelength. In this case, it must be mentioned that generally, the slot length of a tapered slot antenna corresponds to 2 to 4 times the maximum wavelength of the antenna bandwidth. In an example where the antenna assembly is configured as a cellular antenna assembly, the slot length can be 43 mm to 86 mm. In one example, the slot length can be 50 mm to 70 mm, particularly 55 mm to 65 mm. In another specific example, the slot length is 62 mm. All in all, the tapered slots and thus the antenna assembly are very compact.

[0015] It should be noted that, for each of the conical slot antennas, when the slot length is small compared to the maximum wavelength of the bandwidth and the widest slot width is small compared to the maximum wavelength of the bandwidth, the conical slot antenna itself can be considered small compared to the maximum wavelength of the bandwidth.

[0016] In one example, at least three conical slot antennas are coupled by current coupling and / or electromagnetic coupling of the plate-shaped conductors. This has the following effect: the conical slot antennas that form part of the antenna assembly are coupled in the sense that they also influence each other electrically. This can be referred to as strong mutual coupling or tight mutual coupling, especially if the conical slot antennas are very close to each other geometrically. According to one example, the total maximum distance between the slot directions of adjacent conical slot antennas is less than half of the maximum wavelength of the bandwidth. This maximum distance is measured at the outer circumference of the antenna assembly or at the corresponding wide ends of the conical slots of adjacent conical slot antennas. Preferably, the total maximum distance between the slot directions of adjacent conical slot antennas is less than 0.3 times the maximum wavelength of the bandwidth, and further preferably, the total maximum distance between the slot directions of adjacent conical slot antennas is less than 0.1 times the maximum wavelength of the bandwidth. According to another example, the conical slot antennas forming the antenna assembly are smaller than the maximum wavelength of the bandwidth. This results in the antenna assembly being able to operate over an extremely wide frequency range, that is, this enhances the broadband characteristics. In such a configuration, the antenna assembly can support radiation currents with wavelengths much larger than the element size. In the present disclosure, this is the desired effect that leads to a particularly uniform, multi-directional or omnidirectional radiation pattern and / or a particularly uniform multi-band characteristic. In addition, the coupling of three or more conical slot antennas can also be utilized to further reduce the lateral size of the antenna assembly.

[0017] According to one example, the plate-shaped conductors of at least three conical slot antennas are formed by a common conductor. This means that the conductors of each of the conical slot antennas in the conical slot antennas are conductively connected. The explanations provided above apply with necessary modifications. In addition, the fact that the conductors are formed by a common conductor also means that the antenna assembly only requires a single conductor. This is simple and effective both from a structural perspective and a production perspective. In addition, forming the conductors as a common conductor allows for a compact design of the antenna assembly. In addition, such a configuration results in a cost reduction of the antenna assembly.

[0018] According to one example, the common conductor is substantially circular, and the common conductor can be virtually divided into a plurality of circular sectors corresponding to the number of conical slot antennas. Thus, each conical slot antenna is formed by one of the circular sectors, and the conical slot is centrally arranged within the associated circular sector. From a structural perspective, such an antenna assembly is simple and compact. In addition, such an antenna assembly can be produced in an effective manner.

[0019] In one example, the maximum radius of the common conductor corresponds to 0.15 to 0.35 times the maximum wavelength of the bandwidth of the antenna assembly. According to one example, the maximum radius corresponds to 0.2 to 0.3 times the maximum wavelength of the bandwidth of the antenna assembly. In this case, the maximum radius can be determined by measuring the maximum diameter of the common conductor and dividing the maximum diameter by 2. Thus, the common conductor is less than the maximum wavelength. This is beneficial for an overall compact design. In an example where the antenna assembly is configured as a cellular antenna assembly, the maximum radius can be 100 mm to 130 mm, particularly 110 mm to 120 mm. In a specific example, the maximum radius is 113.5 mm. In summary, the antenna assembly is very compact.

[0020] In one example, at least one bar-shaped conductor element is at least partially disposed in at least one of the tapered slots. The bar-shaped conductor element can be an elongated conductor element. Additionally or alternatively, the bar-shaped conductor element can be perpendicular to the slot direction. In one example, at least one bar-shaped conductor element is disposed adjacent to the wide end of the associated slot. According to another example, at least one bar-shaped conductor element is at least partially disposed in each of the tapered slots. Such a bar-shaped conductor element improves the radiation pattern because the uniformity of the radiation pattern is increased. More precisely, using such a bar-shaped conductor element serves to resist distortion of the radiation pattern and mitigate gain variations. This is especially the case if the antenna assembly is used in a high dielectric constant environment.

[0021] According to one example, at least one bar-shaped conductor element is disposed in the same plane as the plate-shaped conductor of the associated tapered slot antenna. According to another example, at least one bar-shaped conductor element is disposed in a plane different from the plate-shaped conductor of the associated tapered slot antenna. This means that at least one bar-shaped conductor element is offset relative to the plate-shaped conductor along a direction oriented perpendicular to the plane defined by the plate-shaped conductor.

[0022] In one example, a group including a plurality of bar-shaped conductor elements is at least partially disposed in at least one of the tapered slots, adjacent to the wide end of the associated slot. According to one example, such a group including a plurality of bar-shaped conductor elements is disposed in each of the tapered slots. Providing such a group of bar-shaped conductor elements has the same effect as providing a single bar-shaped conductor element as already described above. However, providing a group of bar-shaped conductor elements increases the magnitude of the effect.

[0023] According to an example, the form and dimensions of the bar conductor elements of a group are the same. Moreover, multiple bar conductor elements of a group can be evenly spaced apart. This means that all adjacent bar conductor elements have the same distance. According to a variant in which each of the conical grooves contains a group comprising multiple bar conductor elements, all bar conductor elements of the antenna assembly can have the same form and dimensions. Additionally, the spacing within each group can be even, and the distance by which the bar conductor elements are spaced apart can be the same for the entire antenna assembly. This configuration is simple structurally and can thus be produced in an efficient manner.

[0024] According to other examples, the shape and dimensions of the bar conductor elements can vary. Additionally or alternatively, the spacing between adjacent bar conductor elements can vary. When considering the elevation plane, this results in an improved radiation pattern.

[0025] According to yet another example, at least one bar conductor element can be located in one layer and at least one bar conductor element can be located in another layer, where these layers are offset from each other.

[0026] According to an example, the antenna assembly includes four to one hundred conical slot antennas. Examples of the antenna assembly can include 6, 8, 12, 16, 24, 32, 36, 40, 48, 64, 72, or 96 conical slot antennas. It has been found that an antenna assembly comprising four to one hundred slot antennas exhibits a specific performance combination of both multi-directional or omnidirectional radiation patterns and broadband characteristics. Additionally, such an antenna assembly provides good impedance matching capabilities and is very compact. This helps integrate such an antenna assembly into a vehicle both from an electrical and a mechanical perspective.

[0027] In one example, at least a portion of the conductor comprises at least partially transparent or translucent material or a mesh material. In this case, the transparency or translucency applies to the visible spectrum. In the case of using a mesh material, a person can observe through the voids of the mesh. This allows the antenna assembly to be integrated in locations where the transparency or translucency of the vehicle is important or even necessary, such as in glass parts. Thus, the integration of such an antenna assembly is less restricted compared to non-transparent or non-translucent conductors. Therefore, the antenna assembly of the present disclosure can be integrated in places that are mechanically, electrically, and aesthetically suitable. In other words, the flexibility of integration is increased.

[0028] Examples of at least partially transparent or translucent materials include graphene, indium tin oxide (ITO), aluminum zinc oxide (AZO), fluorine-doped tin oxide (FTO), gallium-doped zinc oxide (GZO), ITO / copper / ITO nanocomposite film, indium gallium zinc oxide (InGaZnO4), zinc oxide (ZnO), silver-coated polyester (AgHT-8 or AgHT-4), silver nanowires (AgNW), or copper nanowires (CuNW).

[0029] The mesh material can be a metallic mesh material, such as a copper mesh material.

[0030] According to a second aspect, there is provided a roof assembly for a vehicle. The roof assembly includes a carrier layer and at least one antenna assembly according to the present disclosure. The at least one antenna assembly is disposed on the carrier layer. The carrier layer may also be referred to as a base layer. In respect of the antenna assembly, the above effects, advantages and variations apply mutatis mutandis. This means that the antenna assembly achieves a multi-directional or omnidirectional radiation pattern. This is useful for a roof assembly of a vehicle, since the position and orientation of the vehicle relative to a transmitter or receiver remote from the vehicle typically vary during use of the vehicle. At the same time, the antenna assembly has broadband characteristics. Thus, when forming part of the roof assembly, the antenna assembly can be used in combination with a plurality of wireless services associated with the vehicle. Additionally, the good impedance matching ability of the antenna assembly has the effect that even when the antenna assembly forms part of the roof assembly of the vehicle, the antenna assembly provides high performance. This facilitates the integration of the antenna assembly into the roof assembly from an electrical perspective, especially if the roof assembly includes a high dielectric constant material such as glass. Thus, in the context of the trend towards using more glass materials in roof assemblies, new integration possibilities for the antenna assembly arise. At the same time, the antenna assembly is compact in size, as described in further detail above. This provides the possibility of integrating the antenna assembly into the roof assembly in a way that improves the aerodynamics and / or aesthetics of the vehicle. In summary, the roof assembly forms a reliable means for connecting the associated vehicle to one or more wireless services without having a negative impact on the roof assembly from an aerodynamic or aesthetic perspective.

[0031] According to one example, the antenna assembly is electrically connected to a pair of parallel feed lines. The pair of parallel feed lines extends between the antenna assembly and an edge of the carrier layer. This means that the pair of feed lines is also supported on the carrier layer. Near the edge of the carrier layer, the pair of feed lines can be connected to a power source or a receiver. Thus, the antenna assembly can be operated in a simple and reliable manner.

[0032] According to one example, the roof assembly includes a plurality of antenna assemblies according to the present disclosure, i.e., two or more such antenna assemblies. This facilitates connecting the roof assembly and the associated vehicle to a plurality of wireless services. Additionally or alternatively, when multiple antenna assemblies are used for a single wireless service, this configuration can improve performance.

[0033] According to one example, the carrier layer comprises a polymer. According to another example, the carrier layer contains polyvinyl acetal. In this case, the carrier layer may comprise polyvinyl butyral (PVB) or may be made of polyvinyl butyral (PVB). This material is well suited for forming the carrier layer for an antenna assembly in a roof assembly because it is optically transparent and cost-effective.

[0034] According to one example, the carrier layer has a dielectric constant of 2.6 to 3.5 and / or a loss tangent of 0.04 to 0.06. It should be understood that the dielectric constant is the relative dielectric constant with respect to the dielectric constant of a vacuum. Due to the characteristics of the antenna assembly as described above, the antenna assembly provides good radiation performance when located on the carrier layer. Thus, the roof assembly is well suited for connecting the associated vehicle to a wireless service.

[0035] In one example, the roof assembly further comprises a feeding assembly for the antenna assembly. The feeding assembly and the antenna assembly are offset in a direction perpendicular to the plane defined by the carrier layer. The feeding assembly and the antenna assembly are capacitively coupled. In this case, the carrier layer or any other layer of the roof assembly may be disposed between the antenna assembly and the feeding assembly. Due to the capacitive coupling, the offset between the feeding assembly and the antenna assembly does not require an electrical conductor bridge. This facilitates the production of the roof assembly.

[0036] According to one example, the feeding assembly comprises a single input line and a plurality of power dividers such that each of the conical slot antennas can be fed an associated current. Due to the fact that the feeding assembly is offset with respect to the antenna assembly, sufficient space is provided for the elements of the feeding assembly.

[0037] In one example, the feeding assembly comprises a first feeding sub-assembly capacitively coupled to a first set of conical slot antennas of the antenna assembly and a second feeding sub-assembly capacitively coupled to a second set of conical slot antennas of the antenna assembly. The first feeding sub-assembly and the second feeding sub-assembly are offset in a direction perpendicular to the plane defined by the carrier layer. Thus, different conical slot antennas of the antenna assembly are fed using different sub-assemblies of the feeding assembly. At least two sub-assemblies of the feeding assembly are offset with respect to each other. This means that the different sub-assemblies are located in different layers. In this case, the carrier layer or any other layer of the roof assembly may be disposed between the first sub-assembly and the second sub-assembly. Due to the capacitive coupling, the offset between the feeding assembly and the antenna assembly does not require an electrical conductor bridge. This facilitates the production of the roof assembly. Additionally, providing two sub-assemblies instead of a continuous feeding assembly enhances the flexibility of integrating the feeding assembly into the roof assembly. This is because at least to some extent, the two sub-assemblies can be positioned independently of each other.

[0038] According to one example, each of the feed sub - assemblies includes a single input line and a plurality of power dividers such that each of the associated conical slot antennas can be fed an associated current. Due to the fact that the feed sub - assemblies are offset relative to each other and relative to the antenna assembly, sufficient space is provided for the elements of the feed sub - assemblies.

[0039] In one example, the first feed sub - assembly and the second feed sub - assembly are arranged on opposite sides of the antenna assembly. This is a particularly compact arrangement of the feed sub - assemblies and the antenna assembly within the roof assembly.

[0040] In one example, the feed assembly includes a feed line, where the feed line protrudes from the remainder of the feed assembly. This is particularly applicable when the antenna assembly has a substantially circular envelope profile. In this case, the associated part of the feed assembly that is capacitively coupled to the antenna assembly also has a substantially circular envelope profile. If the feed line protrudes from the remainder of the feed assembly, the feed line protrudes from this substantially circular envelope profile. This facilitates connecting the feed line to an associated power source or receiver. This also applies if the feed assembly includes a plurality of feed sub - assemblies with associated feed lines.

[0041] According to one example, the roof assembly further includes a first cover layer disposed on a first side of the carrier layer. Additionally or alternatively, the roof assembly includes a second cover layer disposed on a second side of the carrier layer. The first cover layer and / or the second cover layer may include or be made of a glass material. The mechanical properties of the glass material are well - suited for the roof assembly of a vehicle. Additionally, the glass material can be transparent or translucent such that the roof assembly can also be transparent or translucent, which is generally desired by vehicle users. Further, the first cover layer and / or the second cover layer can be used to protect the antenna assembly and / or the feed assembly from environmental influences such as mechanical shock.

[0042] According to one example, the first cover layer and / or the second cover layer has a dielectric constant of 2 to 8. In one example, the dielectric constant can be 7.0 to 7.1. Additionally or alternatively, the loss tangent can be 0.0009 to 0.06. According to one example, the loss tangent is 0.01 to 0.03. As previously mentioned, the dielectric constant should be understood as the relative dielectric constant using the dielectric constant of vacuum as a reference. As previously mentioned, the antenna assembly is well - suited to operate in an environment with such a dielectric constant. Thus, a high - performance antenna assembly can be combined with a roof assembly including a glass layer.

[0043] It should be noted that even if the roof assembly is described as including the antenna assembly according to the present disclosure, the roof assembly may include any other antenna, such as a single conical slot antenna. In such an alternative, the antenna assembly according to the present disclosure is replaced by any other antenna such as a single conical slot antenna. All other aspects of the roof assembly remain the same, i.e., the above explanations apply with necessary modifications.

[0044] It should be noted that the above examples can be combined with each other regardless of the aspects involved.

[0045] With reference to the examples described below, these and other aspects of the present disclosure will become apparent and be elucidated. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Examples of the present disclosure will be described below with reference to the following drawings.

[0047] Figure 1 A vehicle including a roof assembly according to the present disclosure is shown, the roof assembly having an antenna assembly according to the present disclosure, wherein the vehicle is using a wireless service provided by a transmitter or a receiver,

[0048] Figure 2 along Figure 1 A separate view of the roof assembly of the vehicle is shown in the direction II in

[0049] Figure 3 showing Figure 2 details of the roof assembly of

[0050] Figure 4 showing Figure 2 details of the roof assembly of Figure 3 where a perspective view opposite to that of

[0051] Figure 5 showing a cross-section along Figure 2 the V-V direction in

[0052] Figure 6 showing Figure 4 another example of the antenna assembly in a view corresponding to the view of

[0053] Figure 7 and Figure 5 showing an example of Figure 6 in a view corresponding to the view of DETAILED DESCRIPTION

[0054] The drawings are only schematic representations and are only used to illustrate the examples of the present disclosure. The same or equivalent elements are provided with the same reference numerals in principle.

[0055] Figure 1Vehicle 10 is shown. The vehicle includes a roof assembly 12 which, in simplified terms, can be named a glass roof assembly.

[0056] The roof assembly 12 includes an antenna assembly 14 and an associated feed network 16 which is capacitively coupled to the antenna assembly 14, as will be further explained below.

[0057] In this example, the antenna assembly 14 is a cellular antenna assembly 14 which covers all sub-6G frequency bands, i.e., the LET frequency bands including the low frequency band (617 MHz - 960 MHz) and the mid-frequency band (1447.9 MHz - 2170 MHz) as well as the 5G frequency bands (e.g., 2300 GHz - 5 GHz). The antenna assembly 14 communicates wirelessly with an antenna 18. The antenna 18 can operate in a transmit mode or a receive mode. In Figure 1 the example shown, the transmitter antenna 18 is mounted on a cell signal tower 20.

[0058] In this configuration, the main directions in which the radio signals exchanged between the antenna assembly 14 and the transmitter antenna 18 arrive and depart are generally uniformly distributed in azimuth but concentrated around an elevation angle θ in the range of 60 degrees to 90 degrees (see Figure 1 and Figure 2 in combination).

[0059] Thus, the radiation pattern of the antenna assembly is omnidirectional in the azimuth plane and spans an angle θ of 60 degrees to 90 degrees, without any deep nulls throughout the frequency band.

[0060] Hereinafter, the roof assembly 12 and the antenna assembly 14 will be described in more detail with reference to Figures 2 to 5 In this case, the antenna assembly 14 can also be named a radiator.

[0061] In the example shown in the figure, the antenna assembly 14 includes a total of 16 tapered slot antennas 22.

[0062] These tapered slot antennas 22 use a plate-shaped common conductor 24.

[0063] This conductor 24 and thus the antenna assembly 14 includes a center point 26.

[0064] Each of the tapered slot antennas 22 includes a tapered slot 28 extending along a slot direction 30. The boundary of each tapered slot 28 follows an exponential function.

[0065] All the slot directions 30 of all the tapered slot antennas 22 are oriented towards the center point 26.

[0066] Furthermore, all the inner ends of all the tapered slots 28 are located on a common circular circumference extending around the center point 26.

[0067] In the same way, all outer ends of all the tapered slots 28 are located on a common circular circumference extending around the central point 26.

[0068] Furthermore, all the tapered slots 28 taper towards the central point 26.

[0069] Additionally, the slot directions 30 and thus all the tapered slots 28 are evenly distributed with respect to the circumference extending around the central point 26.

[0070] This configuration results in a conductor 24 in the shape of a flower or a star.

[0071] Furthermore, at the narrow end of each of the tapered slots 28, an elliptical resonator 32 is provided. The elliptical resonator 32 is formed as a through-hole with an elliptical cross-section.

[0072] Moreover, the tapered slots 28 are arranged in the common conductor 24 such that the respective widest slot widths W of the tapered slot antennas 22 adjacent to each other are directly adjacent. This means that the tapered slots 28 are arranged such that it is geometrically impossible to move the slots 28 further towards the central point 26 without modifying the geometry of the slots 28.

[0073] In the example of the drawings, the widest slot width corresponds to 0.09 times the maximum wavelength of the bandwidth. Expressed in millimeters, the widest slot with W is equal to 44 mm.

[0074] Regarding the length L of the tapered slots 28, this length L corresponds to 0.14 times the maximum wavelength of the bandwidth. Expressed in millimeters, the length L totals 62 mm.

[0075] This results in the maximum radius R of the common conductor 24 corresponding to 0.26 times the maximum wavelength of the bandwidth.

[0076] Expressed in millimeters, the maximum radius R is equal to 113.5 mm.

[0077] Furthermore, due to the above configuration of the common conductor 24, all inner ends of all the tapered slots 28 are arranged on a circular line around the central point 26. The circular line has a diameter D that is 0.25 times the maximum wavelength of the bandwidth. Expressed in millimeters, the diameter D is equal to 107 mm.

[0078] Due to the fact that all the tapered slot antennas 22 use the common conductor 24, the plate-shaped conductors 34 associated with each of the tapered slot antennas 22 are conductively coupled. In this case, each plate-shaped conductor 34 associated with a single tapered slot antenna among the tapered slot antennas 22 can be regarded as a circular sector having the associated tapered slot 28 in the middle thereof.

[0079] The antenna assembly 14 further includes a total of 16 groups of strip conductor elements 36. In this example, each group includes 5 strip conductor elements 36.

[0080] In each group of bar conductor elements 36, each bar conductor element 36 has a length LS of 8 mm and a width WS of 0.5 mm.

[0081] Within one group, all 5 bar conductor elements 36 are arranged in parallel, where the distance DS between adjacent bar conductor elements 36 is equal to 2.5 mm.

[0082] All groups of bar conductor elements 36 are designed in the same way.

[0083] Regarding the arrangement of the group of bar conductor elements 36 in the associated tapered slot 28, all bar conductor elements 36 are oriented parallel to the tangent that can be generated at the point where the associated slot direction 30 intersects the circle enclosing the common conductor 24.

[0084] Moreover, all the bar conductor elements 36 are arranged inside the envelope circle.

[0085] The bar conductor elements 36 are centered on the slot direction 30.

[0086] Thus, the bar conductor elements 36 are arranged at a certain distance from the associated edge of the associated tapered slot 28.

[0087] This means that none of the bar conductor elements 36 are conductively connected to the common conductor 24.

[0088] The bar conductor elements 36 are made of the same material as the common conductor 24.

[0089] In the example shown in the figure, the bar conductor elements 36 and the common conductor 24 are made of copper mesh material.

[0090] Note that for reasons of better visibility, only some of the tapered slot antennas 22, only some of the tapered slots 28, only some of the slot directions 30, only some of the elliptical resonators 32 and only some of the plate-shaped conductors 34 are provided with reference numerals.

[0091] The feeding assembly 16 is used to supply current to the antenna assembly 14. As described above, the feeding assembly 16 is capacitively coupled to the antenna assembly 14.

[0092] For this purpose, the feeding assembly 16 includes a total of 16 fan-shaped stubs 38. Each fan-shaped stub 38 is bounded by two straight edges that intersect at their first respective ends and enclose an angle of approximately 80°. The respective second ends of the straight edges are connected by a circular edge segment.

[0093] Each of the fan-shaped end sections 38 is associated with one of the conical slot antennas 22 in the conical slot antenna and is configured to generate a current in the associated conical slot antenna 22. To this end, each of the fan-shaped end sections 38 is offset from the antenna assembly 14, i.e., offset from the common conductor 24 in a direction perpendicular to the plane defined by the common conductor 24. However, each of the fan-shaped end sections 38 is located opposite the associated slot antenna 22. More precisely, each corner of the fan-shaped end section 38 where two straight edges intersect is placed on the narrow end of the conical slot 28 of the associated conical slot antenna 22.

[0094] In addition, the feeding assembly 16 includes a total of 16 L-shaped conductor segments 40, and each L-shaped conductor segment 40 is conductively connected to the associated fan-shaped end section 38. The L-shaped conductor segments 40 are arranged in the same plane as the fan-shaped end sections 38. In addition, the L-shaped conductor segments 40 are arranged such that they surround the associated elliptical resonator 32.

[0095] All the fan-shaped end sections 38 are fed using the common port 42 of the feeding assembly 16.

[0096] To do this, a network 44 of power dividers 46 is provided between the common port 42 and each of the fan-shaped end sections 38.

[0097] In this case, each of the power dividers is Y-shaped in the sense that it includes a first terminal and two second terminals. The first terminal can be an input terminal and is located at the base of the Y-shape, and the two second terminals are located at the respective upper ends of the Y-shape. The second terminals can be output terminals. Thus, a total of 15 power dividers 46 are used, and the common port 42 and each of the fan-shaped end sections 38 are conductively connected. This means that the input power associated with the common port 42 can be split and supplied to a total of sixteen fan-shaped end sections 38, i.e., the power is divided in a ratio of 1:16. If the antenna assembly 14 is operating in the receiving mode, this applies with the necessary modifications.

[0098] For reasons of better visibility, only some of the fan-shaped end sections 38, only some of the L-shaped conductor segments 40, and only some of the power dividers 46 are provided with reference numerals.

[0099] The feeding assembly 16 is made of a copper mesh material.

[0100] The arrangement of the antenna assembly 14 and the feeding assembly 16 within the roof assembly 12 can be best seen in Figure 5 .

[0101] The roof assembly 12 includes a total of three layers: a carrier layer 48, a first covering layer 50, and a second covering layer 52.

[0102] In this example, the carrier layer is made of polyvinyl butyral (PVB).

[0103] Both the first cover layer 50 and the second cover layer 52 are made of glass.

[0104] In this example, the carrier layer 48 has a dielectric constant of 2.6 to 3.5 and a loss tangent of 0.04 to 0.06. It should be understood that the dielectric constant is the relative dielectric constant with respect to the dielectric constant of vacuum.

[0105] The first cover layer 50 and the second cover layer 52 have a dielectric constant of 7.0 to 7.1 and a loss tangent of 0.01 to 0.03.

[0106] In this example, the antenna assembly 14 and the feeding assembly 16 are arranged on opposite sides of the carrier layer 48.

[0107] Therefore, the feeding assembly 16 and the antenna assembly 14 are offset in a direction perpendicular to the plane defined by the carrier layer 48. The offset dimension corresponds to the thickness of the carrier layer 48.

[0108] As described above, the antenna assembly 14 and the feeding assembly 16 are capacitively coupled. This means that a conductor penetrating the carrier layer 48 is not necessary.

[0109] More precisely, if the roof assembly 12 is used in a vehicle, the side of the carrier layer 48 on which the antenna assembly 14 is arranged corresponds to the top side of the roof assembly 12.

[0110] The first cover layer 50 covers the carrier layer 48 and the antenna assembly 14 on the top side.

[0111] Therefore, if the roof assembly 12 is used in a vehicle, the side of the carrier layer 48 on which the feeding assembly 16 is arranged corresponds to the bottom side of the roof assembly 12.

[0112] The second cover layer 52 covers the carrier layer 48 and the feeding assembly 16 on the bottom side.

[0113] Figure 5 An electromagnetic connector 54 is also shown, which is capacitively coupled to the feeding assembly 16, more precisely to the common port 42 of the feeding assembly 16.

[0114] The electromagnetic connector 54 is used to power the antenna assembly 14 via the feeding assembly 16.

[0115] It should be noted that the electromagnetic connector 54 can be considered to form part of the roof assembly 12. Alternatively, the electromagnetic connector 54 can be considered to form part of the vehicle, i.e., not part of the roof assembly 12.

[0116] Figure 6 and Figure 7 Another example of the roof assembly 12 is shown. Hereinafter, only the differences from the previous example will be described.

[0117] In the examples of Figure 6 and Figure 7 the antenna assembly 14 is the same as in the example of Figures 1 to 5 However, in terms of being integrated into the layers of the roof assembly 12, the antenna assembly 14 is now embedded in the carrier layer 48. This means that the antenna assembly 14 is arranged inside the carrier layer 48, where the antenna assembly 14 is at a certain distance from both the upper side and the lower side of the carrier layer 48.

[0118] Another difference relates to the feed assembly 16. In the examples of Figure 6 and Figure 7 the feed assembly 16 includes a first feed sub - assembly 16a and a second feed sub - assembly 16b.

[0119] Each of the feed sub - assemblies 16a, 16b is configured to feed a total of eight conical slot antennas 22. For this purpose, each of the feed sub - assemblies 16a, 16b is capacitively coupled to the associated conical slot antenna 22.

[0120] In this case, the design of the feed sub - assemblies 16a, 16b generally corresponds to the design of the feed assembly 16 as shown in Figure 4 However, the feed sub - assemblies 16a, 16b have been adapted to a reduced number of the associated conical slot antennas 22.

[0121] Figure 6 The feed sub - assembly 16a is shown. However, the feed sub - assembly 16b is the same.

[0122] When integrated into the roof assembly 12, the feed sub - assembly 16a is capacitively coupled to the first set of conical slot antennas 22 of the antenna assembly 14. For this purpose, the feed sub - assembly 16a is located on the first side of the carrier layer 48, which is the top side in this example.

[0123] The feed sub - assembly 16b is capacitively coupled to the second set of conical slot antennas 22 of the antenna assembly 14. For this purpose, the feed sub - assembly 16b is located on the second side of the carrier layer 48, which is the bottom side in this example.

[0124] Thus, the first feed sub - assembly 16a and the second feed sub - assembly 16b are arranged on opposite sides of the antenna assembly 14.

[0125] In other words, both the first feed sub - assembly 16a and the second feed sub - assembly 16b are offset from the antenna assembly 14 in a direction perpendicular to the plane defined by the carrier layer 48. Moreover, the first feed sub - assembly 16a and the second feed sub - assembly 16b are offset from each other in the same direction.

[0126] In the examples of Figure 6 and Figure 7In the example, the first cover layer 50 covers the first feed sub - assembly 16a and the carrier layer 48 on the top side.

[0127] The second cover layer 52 covers the second feed sub - assembly 16b and the carrier layer on the bottom side.

[0128] Figure 6 and Figure 7 Another difference in the example concerns the power supply of the feed sub - assemblies 16a, 16b. In this example, each of the feed sub - assemblies 16a, 16b includes a common port 42a, 42b electrically connected to the associated sector stub 38.

[0129] In Figure 6 and Figure 7 the example, the common ports 42a, 42b are formed by corresponding feed lines 56a, 56b protruding towards the edge of the roof assembly 12. At the edge of the roof assembly 12, the feed lines 56a, 56b can be conductively connected to the electrical connector 58.

[0130] It should be noted that according to Figure 6 and Figure 7 a variant of the example, the sub - assemblies 16a, 16b can also be powered using electromagnetic connectors, as explained in connection with the first example.

[0131] It should also be noted that even though it has been explained that the roof assembly 12 has a single antenna assembly 14 and a single associated feed assembly 16, the roof assembly 12 can be equipped with two or more antenna assemblies 14 and thus two or more associated feed assemblies 16. Each of the multiple antenna assemblies 14 can be used for different wireless services that can be provided to the vehicle 10.

[0132] It should also be noted that although the roof assembly 12 has been explained in connection with the antenna assembly 14 as shown in Figure 2 and Figure 3 and the feed assembly as shown in Figure 4 and Figure 6 the roof assembly can also include any other antenna assembly instead of the antenna assembly 14. It should be understood that in this case, another feed assembly is also used.

[0133] As used herein, the phrase "at least one" with respect to a list of one or more entities shall be understood to mean at least one entity selected from any one or more of the entities in the list of entities, but not necessarily including at least one of each of the entities specifically listed within the list of entities, and not excluding any combination of the entities in the list of entities. This definition also allows that entities other than those specifically identified within the list of entities to which the phrase "at least one" refers may optionally exist, whether related or unrelated to those specifically identified. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently, "at least one of A and / or B") may in one example refer to at least one A, optionally including more than one A, without B (and optionally including entities other than B); in another example, to at least one B, optionally including more than one B, without A (and optionally including entities other than A); in yet another example, to at least one A, optionally including more than one A, and at least one B, optionally including more than one B (and optionally including other entities). In other words, the phrases "at least one", "one or more", and "and / or" are open-ended expressions which are both conjunctive and disjunctive in operation. For example, each of the expressions "at least one of A, B, and C", "at least one of A, B, or C", "one or more of A, B, and C", "one or more of A, B, or C", and "A, B, and / or C" may represent A alone, B alone, C alone, A and B together, A and C together, B and C together, A, B, and C together, and optionally any combination of any of the foregoing with at least one other entity.

[0134] By studying the drawings, the disclosure, and the appended claims, those skilled in the art can understand and realize other variations of the disclosed examples when practicing the claimed disclosure. In a claim, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may implement the functions of several items or steps recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium provided together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope of the claims.

[0135] List of reference signs

[0136] 10 vehicle

[0137] 12 Roof Assembly

[0138] 14 Antenna Assembly

[0139] 16 Feeding Assembly

[0140] 18 Transmitter Antenna

[0141] 20 Cell Signal Tower

[0142] 22 Conical Slot Antenna

[0143] 24 Common Conductor

[0144] 26 Center Point

[0145] 28 Conical Slot

[0146] 30 Slot Direction

[0147] 32 Oval Resonator

[0148] 34 Plate - shaped Conductor

[0149] 36 Bar - shaped Conductor Element

[0150] 38 Sector - shaped End Segment

[0151] 40 L - shaped Conductor Segment

[0152] 42 Common Port of Feeding Assembly

[0153] 44 Network of Power Divider

[0154] 46 Power Divider

[0155] 48 Carrier Layer

[0156] 50 First Cover Layer

[0157] 52 Second Cover Layer

[0158] 54 Electromagnetic Connector

[0159] 56a Feeding Line

[0160] 56b Feeding Line

[0161] 58 Electrical Connector

[0162] D Diameter

[0163] W Widest Slot Width

[0164] L Length of Conical Slot

[0165] R Maximum Radius of Common Conductor

[0166] LS Length of Bar - shaped Conductor Element

[0167] Width of the WS bar conductor element

[0168] Distance between adjacent bar conductor elements of the DS

Claims

1. An antenna assembly (14) for a vehicle (10), the antenna assembly (14) comprising at least three tapered slot antennas (22), each of the tapered slot antennas (22) comprising a plate-shaped conductor (34) and a tapered slot (28) extending in the plate-shaped conductor (34) and extending in a slot direction (30), in, All slot directions (30) are oriented toward a center point (26) of the antenna assembly (14), wherein all the tapered grooves (28) taper gradually toward the center point (26), and Therein, the groove directions (30) are distributed relative to a circumference extending around the center point (26).

2. The antenna assembly (14) of claim 1, wherein each of the tapered slots (28) has a widest slot width W, and wherein the widest slot widths W of adjacent tapered slot antennas (22) are directly adjacent to each other.

3. The antenna assembly (14) of claim 1, wherein: Each of the tapered slots (28) has a widest slot width W, and wherein the widest slot width W corresponds to 0.05 to 0.15 times the maximum wavelength of the bandwidth of the antenna assembly (14).

4. The antenna assembly (14) of claim 1, wherein: Each of the tapered slots (28) has a slot length L, and wherein the slot length L corresponds to 0.1 to 0.2 times the maximum wavelength of the bandwidth of the antenna assembly (14).

5. The antenna assembly (14) of claim 1, wherein: The plate-shaped conductors (34) of the at least three conical slot antennas (22) are galvanically coupled and / or electromagnetically coupled.

6. The antenna assembly (14) according to claim 5, wherein: The plate-shaped conductors (34) of the at least three tapered slot antennas (22) are formed by a common conductor (24).

7. The antenna assembly (14) of claim 6, wherein: The maximum radius R of the common conductor (24) corresponds to 0.15 to 0.35 times the maximum wavelength of the bandwidth of the antenna assembly (14).

8. The antenna assembly (14) of claim 1, wherein: At least one strip conductor element (36) is at least partially arranged in at least one of the tapered slots (28).

9. The antenna assembly (14) of claim 8, wherein: A group comprising a plurality of strip-shaped conductor elements (36) is at least partially arranged in at least one of the tapered slots (28), adjacent to a wide end of the associated slot (28).

10. The antenna assembly (14) of claim 1, comprising four to one hundred slot antennas (22).

11. A roof assembly (12) for a vehicle (10), comprising a carrier layer (48) and at least one antenna assembly (14) according to any one of the preceding claims, wherein: The at least one antenna component (14) is arranged on the carrier layer (48).

12. The roof assembly (12) of claim 11, further comprising a feed assembly (16) for the antenna assembly (14), wherein the feed assembly (16) and the antenna assembly (14) are offset in a direction perpendicular to a plane defined by the carrier layer (48), and wherein, The feed assembly (16) and the antenna assembly (14) are capacitively coupled.

13. The roof assembly (12) according to claim 12, wherein: The feed assembly (16) includes a first feed subassembly (16a) capacitively coupled to a first group of conical slot antennas (22) of the antenna assembly (14), and a second feed subassembly (16b) capacitively coupled to a second group of conical slot antennas (22) of the antenna assembly (14), wherein the first feed subassembly (16a) and the second feed subassembly (16b) are offset in a direction perpendicular to a plane defined by the carrier layer (48).

14. The roof assembly (12) of claim 13, wherein: The first feed subassembly (16a) and the second feed subassembly (16b) are arranged on opposite sides of the antenna assembly (14).

15. The roof assembly (12) of claim 12, wherein: The feed assembly (16) comprises a feed line (42a, 42b), wherein the feed line (42a, 42b) protrudes from the remaining components of the feed assembly (16).

16. The roof assembly (12) of claim 11, further comprising a first cover layer (50) disposed on a first side of the carrier layer (48) and / or a second cover layer (52) disposed on a second side of the carrier layer (48).

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