Vehicle antenna module

Abstract

The invention relates to a vehicle antenna module (100) comprising a main first printed circuit board (201) housed horizontally in a casing, at least a second printed circuit board (205a) comprising a radiofrequency antenna, mounted vertically on the first printed circuit board (201) and protruding from an upper face of the casing, and a cover (101), mounted on said casing, and configured to cover at least the second printed circuit board (205a), the antenna module (100) being such that the cover (101) comprises a shell (206) and an elastic element (207), the elastic element (207) being configured to exert pressure on the upper edge face of the second board (205a) when the cover is in place on the casing in order to ensure electrical contact between the lower edge face of the second board (205a) and at least one flexible contact element (300) on the surface of the first board (201).

Description

Technical field

[0001] The present invention relates to the field of antennas for road vehicles, and more particularly relates to a vertical antenna module integrated into a roof spoiler of a vehicle. Prior art

[0002] Nowadays, road vehicles are increasingly equipped with compact roof antennas configured to allow the exchange of data between the vehicle and Wi-Fi or cellular communication networks, the reception of radio programs or the reception of signals transmitted by GNSS (Global Navigation Satellite System) geolocation satellites. These antennas are generally referred to as smart antennas because they include signal processing circuits in addition to the antennas themselves.

[0003] Automotive antennas of this type are conventionally housed in an antenna housing located on the roof of the vehicle and protected by a cover, for example a fin-shaped cover, mounted on a base (see for example EP3761446A1, US2021 / 050655A1, WO2017 / 178384A1, FR3092440A3). The antenna module comprises a first horizontal printed circuit, on which is vertically arranged at least one second printed circuit comprising one or more particular antenna patterns. The second printed circuit constitutes the antenna itself which can be electrically connected to one face of the first circuit via a connector fixed to the first board, forming a clamp into which the second board is inserted. Such a method of connection between the first and second circuits is however bulky and expensive.

[0004] Alternatively, the second circuit can be connected to the first circuit by soldering. However, this is a delicate operation that complicates the assembly step and poses reliability problems over time, particularly due to vibration phenomena and / or deformations due to temperature changes that can weaken the solder joints.

[0005] There is therefore a need for an antenna module that does not have the aforementioned drawbacks. Summary of the invention

[0006] For this purpose, a vehicle antenna module according to claim 1 is provided.

[0007] The antenna module is notable in that the cover comprises a shell and an elastic element, the elastic element being configured to exert pressure on the upper edge of the second card when the cover is in place on the housing in order to ensure electrical contact between the lower edge of the second card and at least one flexible contact element on the surface of the first card.

[0008] This results in an assembly of the first card with the second card which is robust, easy to implement and which allows a secure electrical contact between the two perpendicular cards, which resists vibrations, temperature changes and relaxation of the plastic parts due to their aging.

[0009] The flexible contact element with which the lower edge of the second card comes into contact absorbs the play and relative movements of one card in relation to the other, thus ensuring permanent contact.

[0010] The elastic element placed between the cover and the upper edge of the second card exerts vertical pressure on the second card, ensuring that the lower edge of the second card is pressed against the flexible contact elements arranged on the surface of the first card.

[0011] This makes it easier to mount the antenna module and avoids the need for soldering, while ensuring good electrical continuity between the first and second boards. This results in a robust, reliable and easy-to-assemble antenna module.

[0012] According to a particular embodiment, the elastic element is configured to exert pressure on the upper edge of the second card via at least one interference presser.

[0013] In this way, the applied element exerts a point force on one or more points of the upper edge of the antenna. The applied force is thus controlled, unlike continuous contact along the length of the upper edge of the antenna, where irregularities in the cutting of the antenna and / or in the molding of the elastic element would make the pressure force exerted and its distribution on the antenna uncertain.

[0014] According to a particular embodiment, the at least one flexible contact element is of the spring finger type.

[0015] The use of spring fingers ensures contact between the first and second cards at low cost.

[0016] According to a particular embodiment, the at least one flexible contact element is made of a conductive elastomer material.

[0017] Such an arrangement improves contact reliability by preventing oxidation and allows for better absorption of mechanical tolerances. A flexible contact made of conductive elastomer also offers greater resistance to the risk of tearing and / or deformation during handling, unlike metal contacts of the Z-spring or clamp type.

[0018] In a particular embodiment, the second card comprises at least one shoulder forming a stop bearing on the housing to limit the crushing of the at least one flexible contact element by the lower edge of the second card.

[0019] The shoulder abutting the housing limits the vertical travel of the antenna. This controls the crushing of the flexible contact points. This prevents excessive crushing of the flexible contacts from causing permanent deformation of the contact points and impaired electrical continuity. This arrangement improves the reliability of the antenna module.

[0020] According to a particular embodiment, the elastic element is produced by overmolding an internal part of the shell with a thermoplastic elastomer.

[0021] Overmolding allows for greater positioning accuracy of the flexible element. In addition, it can be produced automatically, unlike an added part, which is particularly difficult to handle by a robot given the required flexibility. This improves the quality and production cost of the antenna module.

[0022] In a particular embodiment, the elastic element comprises at least one pair of lateral ribs configured to accommodate the upper edge of the second card and limit its lateral movements.

[0023] The upper part of the antenna is thus held laterally. This avoids the appearance of vibration phenomena likely to cause noise and alter the contact between the vertical card and the main card. Unlike other techniques in which the upper part of the card is held by formations provided for this purpose inside the cover such as a slot, the insertion of the printed circuit card including the antenna between flexible ribs can be carried out with controlled mechanical effort, facilitating assembly and causing no stress to the printed circuit.

[0024] In a particular embodiment, the elastic element has a hardness of between 45 and 55 shore A, preferably 50 shore A.

[0025] Such a hardness value makes it possible to limit the assembly effort required when fitting the cover while allowing satisfactory absorption of vibrations.

[0026] The elastomer is further formulated to provide a low dielectric loss tangent so as not to disrupt the operation of the vertical antennas housed by the cover.

[0027] According to another aspect, the invention relates to a vehicle comprising an antenna module as described above.

[0028] Such a vehicle has at least advantages similar to those conferred on the antenna module described above. Brief description of the figures

[0029] Other aspects, aims and advantages of the invention will appear on reading the following description of one of its embodiments, given by way of non-limiting example. The invention will also be better understood with reference to the attached drawings in which: [ Fig. 1 ] There figure 1 is a perspective view of an antenna module according to a particular embodiment. Fig. 2 ] There figure 2 is an exploded view of an antenna module according to a particular embodiment. Fig. 3 ] There figure 3 is a sectional view of an antenna module according to a particular embodiment, taken along the section line AA shown in the figure 1 [ Fig. 4 ] There figure 4 is a view from below of the interior of the cover comprising an elastic element and a PCB antenna, according to a particular embodiment. Detailed description

[0030] In the following description, numerous specific details are set forth so that a person skilled in the art may better understand the present invention. However, it is obvious that the implementation of the present invention may not include some of these specific details. Furthermore, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, it is conceivable to implement the present invention with any combination of the following features and elements, whether or not they involve different embodiments. Therefore, the aspects, features, embodiments, and advantages that will be described are for illustrative purposes only and should not be considered as elements or limitations of the claims unless explicitly set forth in the claims.

[0031] There figure 1 represents a perspective view of an antenna module 100 according to a particular embodiment. The antenna module 100 is intended to be integrated into the roof of a vehicle and comprises a housing 102 on which a cover 101 is fixed. The housing 102 comprises at least one connector 103 intended to connect an electronic card included in the housing 102 to at least one device of the vehicle in which the antenna module is integrated.

[0032] There figure 2 is an exploded view of the antenna module 100 according to a particular embodiment. The housing 102 is composed of a lower part 200 and an upper part 202 between which is arranged horizontally a main printed circuit board 201, called the motherboard. The lower 200 and upper 202 parts of the housing are for example assembled by a set of screws. In a particular embodiment, the upper part 202 is made of metal in order to ground the module to the vehicle and to shield the junction between the antennas and the main board.

[0033] The motherboard 201 may be composed of a single board comprising, for example, power supply circuits, baseband signal processing circuits and a radio frequency processing circuit. However, without modifying the invention, the motherboard may be composed of separate boards supporting different circuits.

[0034] The upper portion 202 of the housing includes a recess 203 through which one or more vertical PCB antennas 205a, 205b protrude. PCB antenna means printed circuit boards on which one or more tracks forming an antenna pattern are traced and / or printed circuit boards comprising one or more three-dimensional antennas, such as a wire extending over the board, a metal element or even a chip antenna.

[0035] Although the figures illustrating a particular embodiment of the antenna module show two PCB antennas 205a and 205b, the number and position of these antennas may vary without modifying the invention. For example, the antenna module may comprise a single antenna 205a.

[0036] For the sake of clarity and conciseness, this description will focus on describing the features of the invention in relation to antenna 205a, the same inventive concepts applying analogously to antenna 205b and / or other vertical PCB antennas that may be included in the antenna module.

[0037] The antenna 205a is for example configured to allow the transmission and / or reception of radio frequency signals. It may be an antenna for receiving an analog or digital radio signal, a Wi-Fi signal, or an antenna for establishing connections to a cellular access network, for example a 2G, 3G, 4G or 5G access network.

[0038] The PCB antenna 205a is arranged perpendicular to the motherboard 201. According to a particular embodiment, the antenna module comprises a guide element 204 for holding the PCB antenna 205a in a vertical position, perpendicular to the motherboard. In a particular embodiment, the guide element is constituted by a particular formation of the upper part 202 of the housing.

[0039] There figure 2 also shows a cover 101 in the shape of a “shark fin” intended to cover the antenna 205a. The cover 101 comprises a shell 206 made of a non-metallic material and fixed to the upper part 202 of the housing, for example by screws or clips, as well as an elastic element 207.

[0040] The elastic element 207 is interposed between the upper internal portion of the shell 206 and the upper portion of the antenna 205a such that at least a portion of the elastic element 207 is in contact with the upper internal portion of the shell 206 and the upper edge of the PCB antenna 205a. The elastic element is preferably a thermoplastic elastomer (TPE) of low hardness, for example 50 Shore A, and having a low dielectric loss tangent, preferably less than 0.07 at 6 GHz. In a particular embodiment, the elastic element 207 is overmolded in the shell 206.

[0041] It is noted that the upper part of the shell 206 and the upper edge of the antenna 205a have a substantially identical profile. The shell 206 being intended to protrude from the roof of a vehicle, its shark fin shape makes it possible to limit aerodynamic disturbances. The shape of the antenna 205a is thus adapted to optimally occupy the interior of the shell 206 and to allow the elastic element 207 to be inserted between the shell 206 and the antenna 205a using a minimum of material.

[0042] There figure 3 is a longitudinal section of the assembled antenna module, along a section line AA shown in the figure 1 . There figure 3 shows flexible contacts 300 intended to electrically connect the antenna 205a to the motherboard 201. The flexible contacts 300 are in contact with a conductive portion of the lower edge of the antenna 205a and connected to a circuit of the motherboard. They thus allow electrical continuity between the antenna 205a and the motherboard while allowing relative movement of the antenna 205a with respect to the motherboard 201. Such an assembly thus offers tolerance to deformations, expansions or vibrations without loss of electrical continuity. According to a particular embodiment, the flexible contact points 300 are spring-type contact fingers. According to a particular embodiment, the flexible contact points 300 are made of a conductive elastomer material, for example a resilient silicone elastomer loaded with copper particles.

[0043] Of course, the number of flexible contacts depends on the number and / or type of antenna 205a with which the antenna module is equipped. The motherboard 201 may, for example, have a single flexible contact point 300.

[0044] The antenna 205a comprises at least one shoulder 301 configured to bear on a portion of the upper part 202 of the housing so as to guarantee a minimum spacing between the lower edge of the antenna 205a and the motherboard and limit the crushing of the contact points 300.

[0045] There figure 3 shows two interfering pressers 302 formed by the elastic element 207 and configured to exert pressure on the upper edge of the antenna 302 when the shell 206 is in place and thus ensure that the shoulders 301 are pressed against the housing and that the flexible contact points 300 are minimally crushed. The width of a presser is, for example, between 1.5 and 3 millimeters.

[0046] An interference presser is understood to mean a portion of the elastic element 207 whose height is greater than the space available between the top of the internal portion of the shell 206 and the upper edge of the antenna 205a, so that when the cover is in place, the elastic element 207 is compressed between the shell 206 and the antenna 205a and exerts vertical pressure from top to bottom on the upper edge of the antenna 205a.

[0047] According to a particular embodiment, the upper edge of the antenna 205a comprises at least one horizontal portion 303 on which a presser 302 applies pressure, so that the pressure is exerted vertically on the card.

[0048] There figure 4 is an interior view of the cover 101 according to a particular embodiment in which the elastic element 207 and the antenna 205a can be seen. figure 4 shows lateral holding elements, such as a pair of ribs 400, arranged opposite each other and configured to accommodate the PCB antenna 205a and limit its lateral movements. Such ribs are, for example, 2 to 5 millimeters wide. Such an arrangement allows the upper part of the antenna 205a to be held when the cover 101 is put in place and the damping of vibration phenomena likely to appear in the upper part of the antenna 205a. In addition, the insertion of the upper part of the antenna 205a between the ribs when the cover 101 is put in place can be carried out with a controlled mechanical force, thus limiting the stress caused to the boards.

[0049] Finally, the figure 4 shows a conductive part 501 of the lower edge of the antenna 205a intended to establish electrical contact with the flexible contacts 300 of the motherboard described above.

[0050] As previously indicated, a particular embodiment of the antenna module may comprise several PCB antennas. For example, the figures 2 , 3 And 4 show a second vertical PCB antenna 205b, arranged perpendicular to the motherboard, the plane of the antenna 205b being perpendicular to the plane of the antenna 205a. The figure 4 shows a presser 401 formed in the elastic element 207 and configured to exert pressure on the upper edge of the antenna 205b in order to press it against a flexible contact element on the surface of the motherboard. In a manner similar to what was previously described with reference to the antenna 205a, the antenna 205b comprises at least one shoulder denoted 206 on the figure 2 configured to rest on the upper part 202 of the housing and limit the crushing of a flexible contact referenced 300 on the figure 3 allowing electrical continuity between the antenna 205b and the motherboard 201. The lateral movements of the antenna 205b are limited by holding elements referenced 402 on the figure 4 , such as ribs or tongues, formed by the flexible element 207.

[0051] The characteristics described above make it possible to obtain a particularly reliable antenna module whose assembly costs and efforts are reduced compared to the prior art.

Claims

1. Vehicle antenna module (100) comprising: - a housing, - a first main printed circuit board (201) seated horizontally in the housing, - at least one second printed circuit board (205a) comprising a radio frequency antenna mounted vertically on the first printed circuit board (201) and projecting from an upper face of the housing, - a cover (101) mounted on said housing and designed to cover at least the second printed circuit board (205a), the antenna module (100) being characterized in that the cover (101) comprises a shell (206) and an elastic element (207), the elastic element (207) being designed to exert a pressure on the upper edge of the second board (205a) when the cover is in place on the housing in order to provide an electrical contact between the lower edge of the second board (205a) and at least one flexible contact element (300) on the surface of the first board (201).

2. Antenna module according to Claim 1, wherein the elastic element is designed to exert a pressure on the upper edge of the second board by means of at least one interference pusher.

3. Antenna module according to any one of the preceding claims, wherein the at least one flexible contact element is a spring-loaded pin.

4. Antenna module according to either of Claims 1 and 2, wherein the at least one flexible contact element is made of a conductive elastomer.

5. Antenna module according to any one of the preceding claims, wherein the second board comprises at least one shoulder forming a stop bearing against the housing to limit the compression of the at least one flexible contact by the lower edge of the second board.

6. Antenna module according to any one of the preceding claims, wherein the elastic element is made by overmoulding an internal part of the shell with a thermoplastic elastomer.

7. Antenna module according to any one of the preceding claims, wherein the elastic element comprises at least one pair of lateral ribs designed to receive the upper edge of the second board and to limit the lateral displacements thereof.

8. Antenna module according to any one of the preceding claims, wherein the elastic element has a Shore A hardness of between 45 and 55.

9. Vehicle comprising an antenna module according to any one of the preceding claims.

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