communication equipment

Abstract

This communications device comprises a base board, an antenna unit, and a cover. The antenna unit is provided at least on one primary surface of the base board. The cover is provided on the primary surface of the base board so as to touch at least a portion of the upper part of the antenna unit.

Description

[Technical Field]

[0001] The present invention relates to a communication device. [Background technology]

[0002] Conventionally, radar devices have been used for inter-vehicle communication between automobiles, perimeter monitoring, etc. In such radar devices, the antenna unit is generally covered with a radome (covering unit). As described in Patent Document 1, such a radome has a space between the top of the antenna unit and the radome. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 145305 Summary of the Invention [Means for solving the problem]

[0004] A communication device according to the present disclosure includes a substrate, an antenna unit, and a covering unit. The antenna unit is located on at least one main surface of the substrate. The covering unit is located on the main surface of the substrate so as to abut at least a portion of an upper portion of the antenna unit. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is an explanatory diagram illustrating a communication device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0006] When a space (layer of air) exists between the top of the antenna unit and the radome, as in conventional communication devices, moisture is likely to be generated due to temperature changes in the air in the space. This moisture can easily cause deterioration of the metal antenna unit. Therefore, there is a demand for communication devices that are less likely to generate moisture due to temperature changes and whose antenna unit is less likely to deteriorate.

[0007] As described above, in the communication device according to the present disclosure, the covering is positioned on the main surface of the substrate so as to abut at least a portion of the upper part of the antenna part. Therefore, there is no space (air layer) between the upper part of the antenna part and the covering part. Therefore, in the communication device according to the present disclosure, moisture due to air is less likely to be generated between the antenna part and the covering part, and the antenna part is less likely to deteriorate. In this specification, "there is no air layer" also includes the case where there is an unavoidable gap between the upper part of the antenna part and the covering part due to manufacturing.

[0008] A communication device according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing a communication device 10 according to an embodiment of the present disclosure.

[0009] A communication device 10 according to an embodiment of the present disclosure includes a substrate 1, an antenna unit 2, and a covering unit 3. The substrate 1 included in the communication device 10 according to an embodiment is not limited to a substrate generally used in communication devices.

[0010] Examples of such a substrate 1 include circuit boards such as printed circuit boards. Specifically, the substrate 1 has a structure in which insulating layers and wiring conductor layers are alternately laminated. The insulating layers are formed of resins such as epoxy resin, bismaleimide-triazine resin, polyimide resin, and polyphenylene ether resin. The substrate 1 may contain insulating fabric materials such as glass fiber, glass nonwoven fabric, aramid nonwoven fabric, aramid fiber, and polyester fiber as reinforcing materials. Furthermore, the substrate 1 may have inorganic fillers dispersed therein, such as silica, barium sulfate, talc, clay, glass, calcium carbonate, and titanium oxide. Although an insulating layer containing an organic resin is given as an example here, the present disclosure also provides that the insulating layer may be made of not only organic resin but also ceramic. The wiring conductor layer is formed of a metal such as copper.

[0011] The thickness and size of the substrate 1 are not limited as long as they are large enough to accommodate the antenna unit 2 on at least one of the main surfaces 11. The thickness and size of the substrate 1 are set appropriately depending on the application of the communication device 10.

[0012] The antenna unit 2 is a member that transmits and receives radio waves, and is disposed on at least one of the main surfaces 11 of the substrate 1. In the communication device 10 according to one embodiment, the frequency of the radio waves that can be transmitted and received is not limited and is set appropriately depending on the application. The material used for the antenna unit 2 may be a metal. Preferably, the metal has high conductivity. Examples of such metals include base metals such as copper and nickel, precious metals such as gold, platinum, and silver, aluminum, brass, etc.

[0013] As such, in the communication device of the present disclosure, there is no air gap between the upper portion 21 of the metal antenna unit 2 and the covering 3. In other words, at least a portion of the upper portion 21 of the metal antenna unit 2 is in contact with the covering 3. This allows for the antenna unit 2 to be made of a base metal such as copper, which has lower corrosion resistance than noble metals. In this case, the surface of the metal constituting the antenna unit 2 may be exposed. Note that the surface of the antenna unit 2 that contacts the covering 3 may have an organic resin layer that is originally formed on the material of the antenna unit 2 and has undergone silane coupling treatment, benzotriazole treatment, or the like. Such an organic resin layer may make it difficult for moisture to penetrate the interface between the antenna unit 2 and the covering 3, or may facilitate moisture repelling.

[0014] The covering 3 is located on the main surface 11 of the substrate 1 so as to abut against the antenna unit 2. In the communication device 10 according to one embodiment, the covering 3 abuts against both the antenna unit 2 and the substrate 1. That is, no air layer exists between the upper portion 21 of the antenna unit 2 and the covering 3. With this configuration, the communication device 10 according to one embodiment is less susceptible to moisture caused by air, making the antenna unit 2 less susceptible to deterioration. Furthermore, since the covering 3 abuts against the upper portion 21 and side portion 22 of the antenna unit 2, as in the communication device 10 according to one embodiment, the possibility of radio wave reflection can be reduced. As a result, radio wave attenuation can be more unlikely to occur. In this specification, the term "air layer" refers to a layer in which the entire upper portion 21 of the antenna unit 2 is in contact with air.

[0015] The covering 3 may be disposed at a height where there is no air gap between the substrate 1 and the antenna 2. When the covering 3 is in contact with the substrate 1 and the antenna 2, the communication device is less susceptible to stresses that occur between the covering 3 and the substrate 1 and the antenna 2 due to changes in the ambient temperature. This improves the durability of the communication device.

[0016] Furthermore, if there is a space (air layer) between the top of the antenna unit and the radome, as in conventional radomes, it is necessary to precisely determine the thickness of the space (air layer) (the distance between the bottom surface of the radome and the top surface of the antenna unit) and align the antenna unit and the radome. Even a slight error in the thickness of the space or in the alignment could change the diffusion of radio waves. Furthermore, forming the radome to be as uniform in thickness as possible with high precision would result in high costs. This problem can be solved by abutting the top 21 of the antenna unit 2 with the covering 3.

[0017] The covering portion 3 is formed of, for example, a resin, and examples of such resins include a resin containing cyclic olefin copolymer as a main component, a polyimide resin, a polyphenylene ether resin, etc. Among these resins, cyclic olefin copolymer has a low water absorption rate (0.02% or less), making it more difficult for moisture to be generated.

[0018] A cyclic olefin copolymer is a polyolefin copolymer having a cyclic structure. The cyclic olefin copolymer is obtained by polymerizing a cyclic olefin with another monomer copolymerizable with the cyclic olefin. The ratio of the cyclic olefin to the other monomer is not particularly limited. For example, the other monomer is used in a ratio of 1 part by mass to 100 parts by mass per 100 parts by mass of the cyclic olefin.

[0019] Examples of cyclic olefins include norbornene-based monomers, cyclic diene-based monomers, and vinyl alicyclic hydrocarbon-based monomers. Specific examples of cyclic olefins include norbornene, vinylnorbornene, phenylnorbornene, dicyclopentadiene, tetracyclododecene, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cyclohexadiene, and cyclooctadiene. These cyclic olefins may be used alone or in combination of two or more.

[0020] Examples of other monomers copolymerizable with cyclic olefins include linear olefins, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, aromatic vinyl compounds, unsaturated nitriles, and aliphatic conjugated dienes. Specific examples of such monomers include ethylene, propylene, butene, acrylic acid, methacrylic acid, fumaric acid, fumaric anhydride, maleic acid, maleic anhydride, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, styrene, vinyltoluene, acrylonitrile, methacrylonitrile, 1,3-butadiene, 2-methyl-1,3-butadiene, and 2,3-dimethyl-1,3-butadiene. These other monomers may be used alone or in combination of two or more.

[0021] In the present disclosure, a "resin containing a cyclic olefin copolymer as a main component" refers to a resin containing 50% by mass or more of the above-mentioned cyclic olefin copolymer, excluding additives described below. That is, a "resin containing a cyclic olefin copolymer as a main component" may be a resin consisting only of a cyclic olefin copolymer (100% by mass of cyclic olefin copolymer), or may be a resin containing a cyclic olefin copolymer and a resin other than a cyclic olefin copolymer.

[0022] Examples of resins other than the cyclic olefin copolymer include acrylic resins, epoxy resins, phenolic resins, melamine resins, urea resins, polyamides, polyimides, etc. These resins may be used alone or in combination of two or more, taking into consideration, for example, compatibility with the cyclic olefin copolymer.

[0023] Examples of cyclic olefin copolymers include thermoplastic cyclic olefin copolymers and thermosetting cyclic olefin copolymers. Among these, cyclic olefin copolymers including thermosetting cyclic olefin copolymers are preferred. For example, a polymer composite of a thermoplastic cyclic olefin copolymer and a thermosetting cyclic olefin copolymer may be used as long as heat resistance can be ensured. Among these, thermoplastic cyclic olefin copolymers are more flexible than thermosetting resins even in a solid state, allowing for closer adhesion to the antenna portion 2, which protrudes from the substrate 1. The composite of a thermoplastic cyclic olefin copolymer and a thermosetting cyclic olefin copolymer exhibits heat resistance due to the presence of the thermosetting cyclic olefin copolymer, allowing the communication device 10 to be placed in high-temperature environments (e.g., in the engine section of an automobile).

[0024] The cyclic olefin copolymer may have a relative dielectric constant of 3 or less at a frequency of 10 GHz or more and 1 THz or less. Using a cyclic olefin copolymer with such a relative dielectric constant allows the thickness of the covering 3 to be relatively thin (for example, 10 mm or less, particularly 5 mm or less). As a result, even if a step due to the thickness of the antenna unit 2 exists when the antenna unit 2 protrudes from the surface of the substrate 1, gaps are unlikely to form on the side of the step (the side of the antenna unit 2). The thickness of the covering 3 is preferably 0.1 mm or more to improve moisture resistance and increase the strength as a protective film. Furthermore, the communication device can be made thinner.

[0025] The covering portion 3 may have an in-plane (X and Y directions) variation in relative permittivity of 0.005 or less. The in-plane (X and Y directions) refers to the range of the plane formed by the X and Y axes when the substrate 1, including the antenna portion 2, is viewed in a plan view and the surface of the substrate 1 is defined by coordinates in the X and Y directions that are virtually orthogonal to each other. If the in-plane variation in relative permittivity is 0.005 or less, the anisotropy of the transmission and reflection characteristics of the input and output radio waves is reduced. As a result, for example, the anisotropy of horizontally polarized waves of the antenna portion 2 can be reduced.

[0026] The thickness of the covering portion 3 is not limited as long as it is thick enough to cover the antenna portion 2. The thickness of the covering portion 3 may be partially uneven. In other words, the covering portion 3 may include a portion of uneven thickness in the region including the antenna portion 2 and its surroundings. For example, the covering portion 3 may be thicker in the region where the antenna portion 2 is located than in other regions. In this way, if the covering portion 3 is thicker in the region where the antenna portion 2 is located, the antenna portion 2 can be efficiently protected from mechanical shock. In this specification, the "thickness of the covering portion 3" means the dimension of the covering portion 3 in the direction perpendicular to one main surface 11 of the substrate 1.

[0027] The method for manufacturing the communication device 10 according to one embodiment is not limited, and may be, for example, as follows. First, as described above, a substrate 1 having a structure in which insulating layers and wiring conductor layers are alternately stacked is prepared. Next, an antenna unit 2, for example, is mounted on at least one main surface 11 of the substrate 1. Next, a covering unit 3 is formed so as to abut on the antenna unit 2.

[0028] The communication device is not limited to a structure in which the antenna unit 2 is mounted on the substrate 1. For the purpose of reducing the height of the antenna unit 2, a structure in which a metal film that becomes the antenna unit 2 is attached to the surface of the substrate 1 may also be used. Alternatively, a structure in which a part of the metal film that becomes the antenna unit 2 is buried to a predetermined depth from the surface of the substrate 1 may also be used. The structure in which a part of the metal film that becomes the antenna unit 2 is buried to a predetermined depth from the surface of the substrate 1 may be a structure similar to that of a so-called printed circuit board, which is formed by, for example, attaching a metal foil of a predetermined area to the surface of an insulating layer made of organic resin and then performing a heat and pressure treatment.

[0029] The covering portion 3 is formed, for example, as follows. First, a cyclic olefin copolymer in a sheet or paste form is attached to the surface of the substrate 1 including the antenna portion 2. At this time, care is taken to ensure that no space (air layer) is formed between the covering portion 3 and the antenna portion 2. The covering portion 3 is preferably attached without any gaps to the main surface 11 on which the antenna portion 2 is disposed, among the surfaces of the substrate 1 on which the antenna portion 2 is mounted. Thereafter, the covering portion 3 is formed by curing the cyclic olefin copolymer.

[0030] The communication device 10 according to the embodiment obtained in this manner is mounted on, for example, a radar device for vehicle-to-vehicle communication between automobiles, a radar device for perimeter monitoring, or the like.

[0031] The communication device according to the present disclosure is not limited to the communication device 10 according to the above-described embodiment. In the communication device according to the present disclosure, the covering portion may be located on the main surface of the substrate so as to abut at least a portion of the upper portion of the antenna portion, and the covering portion may abut the entire upper portion of the antenna portion. By having the covering portion abut the entire upper portion of the antenna portion, an air layer does not exist above the antenna portion. As a result, it is possible to make it more difficult for radio waves emitted from the antenna portion and radio waves received by the antenna portion to be attenuated. [Explanation of symbols]

[0032] 1 board 11 Main surface 2 Antenna section 21 Upper 22 Side 3 Covering 10. Communications equipment

Claims

1. The antenna includes a substrate, an antenna portion, and a covering portion, the antenna portion is located on at least one main surface of the substrate, the covering portion is located on the main surface of the substrate so as to abut on at least a part of an upper portion of the antenna portion, The coating portion is made of a resin containing a cyclic olefin copolymer as a main component and has a thickness of 5 mm or less. Communication equipment.

2. The communication device according to claim 1 , wherein the covering portion abuts against the entire upper surface of the antenna portion.

3. The communication device according to claim 1 , wherein the covering portion abuts against an upper portion and a side portion of the antenna portion.

4. The communication device according to claim 1 or 2, wherein the cyclic olefin copolymer has a relative dielectric constant of 3 or less at a frequency of 10 GHz or more and 1 THz or less.

5. The communication device of claim 1 or 2, wherein the cyclic olefin copolymer comprises a thermosetting cyclic olefin copolymer.

6. 3. The communication device according to claim 1, wherein the covering has a relative dielectric constant whose change in plane (XY directions) is 0.005 or less.

7. The communication device according to claim 1 , wherein the covering portion has a thickness greater in a region where the antenna portion is disposed than in other regions.

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