Shielded cable

Abstract

A shielded cable according to the present application includes an electromagnetic-noise-shielding layer. The electromagnetic-noise-shielding layer is a laminate including a base material and a magnetic layer. The magnetic layer includes a soft magnetic material and a resin. The imaginary part of the relative permeability of the magnetic layer is 2.0 or more at a frequency of 2 GHz, and the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation amount in a frequency range of 2-3 GHz is 5 dB or less in a relationship diagram between the shielding attenuation amount and the frequency measured in accordance with IEC 62153-4.

Description

Shielded Cable

[0001] This application relates to a shielded cable provided with an electromagnetic noise shielding layer for shielding electromagnetic waves in the MHz to GHz band.

[0002] With the development of wireless communication technologies represented by mobile phones, various devices and sensors are being wirelessly connected to networks. Also, in the medical field, from the perspective of infection prevention, the equipment is becoming cordless, and medical devices are starting to be wirelessly connected. These communications require high-speed large-capacity at relatively short distances and use high frequencies. With the increase in the number of devices using such high frequencies, the risk of malfunctions due to electromagnetic noise generated by the devices and interference with the used electromagnetic waves, etc., causing problems in electronic devices and communications is increasing. Furthermore, in recent years, the installation of millimeter-wave radars for the purpose of preventing automobile collision accidents has also started. Malfunctions in these medical and automotive field devices affect human lives, so there must be no malfunction. In such a situation, in recent years, as a measure to prevent problems caused by electromagnetic noise and the interference caused by it, so-called EMC (Electromagnetic Compatibility) measures, in addition to the conventional braided noise shielding layer, it has been proposed to incorporate a high-frequency noise shielding layer into shielded cables such as coaxial cables that transmit high-frequency signals.

[0003] By providing shielded cables incorporating a high-frequency noise shielding layer to society, among the 17 goals of the Sustainable Development Goals (SDGs) established by the United Nations, it is possible to contribute to the achievement of Goal 3 (Ensure healthy lives and promote well-being for all people of all ages), Goal 9 [Build resilient infrastructure, promote inclusive and sustainable industrialization, and foster innovation], and Goal 12 (Ensure sustainable consumption and production patterns).

[0004] Conventionally, a communication cable with a shielding function against external electromagnetic waves and for transmitting high-frequency signals has been used, for example, for transmitting the image signal of an in-vehicle camera. Such a communication cable needs to transmit a larger amount of signals compared to a signal cable, so the carrier frequency of the signal is as high as several GHz to several tens of GHz, and it is necessary to transmit high-frequency signals.

[0005] Generally, shielded cables such as twisted-rod cables and coaxial cables are often used to transmit high-frequency signals. For example, in the case of coaxial cables, a braided noise shielding layer is placed between the core wire (internal conductor) in the center of the cable and an insulator for the purpose of noise shielding. However, for high-frequency signals, the braided noise shielding layer alone is insufficient for noise shielding, and further noise countermeasures were necessary.

[0006] In this context, Figure 2 of Patent Document 1 proposes a magnetic shielded cable equipped with a magnetic shielding layer in which, in addition to the conventional braided shielding layer, a magnetic powder layer is further sandwiched between coating layers. However, when the shielding attenuation of such a shielded cable equipped with a magnetic shielding layer is measured in accordance with IEC 62153-4, a standard for evaluating electromagnetic wave shielding performance, it has been found that the shielding attenuation may fluctuate with respect to the measurement frequency. This fluctuation in shielding attenuation poses a problem in the practical use of shielded cables because the electromagnetic wave shielding performance changes depending on the frequency of the external electromagnetic waves.

[0007] Furthermore, prior art documents related to the shielded cable of this application include Patent Documents 2 and 3. Patent Document 2 discloses a communication wire having a magnetic sheath layer containing a magnetic material. Patent Document 3 discloses a method for manufacturing a coaxial cable.

[0008] Japanese Patent Publication No. 2016-197509, Japanese Patent Publication No. 2022-108557, Japanese Patent Publication No. 2006-252937

[0009] This invention solves the above problem and provides a shielded cable that exhibits small fluctuations in electromagnetic noise shielding performance in a specific frequency band and has a stable electromagnetic noise shielding function.

[0010] The shielded cable of the present invention includes an electromagnetic noise shielding layer, the electromagnetic noise shielding layer is a laminate comprising a base material and a magnetic layer, the magnetic layer comprises a soft magnetic material and a resin, the imaginary part of the relative permeability of the magnetic layer is 2.0 or more at a frequency of 2 GHz, and in a relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz is 5 dB or less.

[0011] According to the present invention, it is possible to provide a shielded cable with stable electromagnetic noise shielding functionality and minimal fluctuations in electromagnetic noise shielding performance in a specific frequency band. Furthermore, according to a preferred embodiment of the present invention, it is possible to provide a shielded cable that suppresses increases in cable diameter and cable weight.

[0012] Figure 1 is a schematic cross-sectional view of the coaxial cable according to Embodiment 1. Figure 2 is a schematic cross-sectional view of the coaxial cable according to Embodiment 2. Figure 3 is a schematic cross-sectional view of the coaxial cable according to Embodiment 3.

[0013] An embodiment of the shielded cable of the present invention will now be described. The shielded cable of this embodiment includes an electromagnetic noise shielding layer, the electromagnetic noise shielding layer is a laminate including a base material and a magnetic layer, the magnetic layer includes a soft magnetic material and a resin, the imaginary part of the relative permeability of the magnetic layer is 2.0 or more at a frequency of 2 GHz, and in a relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz is 5 dB or less.

[0014] According to the inventors' studies, the variation in the shielding attenuation measured in accordance with IEC 62153-4 with respect to the measurement frequency was found to depend on the imaginary part of the relative permeability of the magnetic layer, and that the larger the imaginary part of the relative permeability of the magnetic layer, the smaller the variation. Therefore, in this embodiment, the imaginary part of the relative permeability of the magnetic layer was set to 2.0 or higher at a frequency of 2 GHz. Here, in order to increase the imaginary part of the relative permeability of the magnetic layer, it is effective to select a soft magnetic powder used in the magnetic layer that has a high imaginary part of relative permeability at the desired frequency, and to increase the packing density of this soft magnetic powder within the magnetic layer.

[0015] Thus, the imaginary part of the relative permeability of the magnetic layer, which affects the variation in the shielding attenuation, is influenced by the imaginary part of the relative permeability of the soft magnetic powder and the packing density of the soft magnetic powder in the magnetic layer made using this powder. Furthermore, the imaginary part of the relative permeability of the soft magnetic powder is influenced by the type of soft magnetic powder, its size (particle diameter), and its shape (flat, spherical, etc.). Moreover, the packing density of the soft magnetic powder in the magnetic layer is influenced by the temperature, pressure, and time of the pressurized heat treatment during the manufacturing of the magnetic layer. In other words, the imaginary part of the relative permeability of the magnetic layer is a value that reflects the influence of all the various factors that affect both the imaginary part of the relative permeability of the soft magnetic powder and the packing density of that soft magnetic powder.

[0016] Therefore, by appropriately setting the conditions related to these factors, the imaginary part of the relative permeability of the magnetic layer can be increased, and as a result, the variation in the shielding attenuation measured in accordance with IEC 62153-4 with respect to the measurement frequency can be suppressed.

[0017] In the shielded cable of this embodiment, the imaginary part of the relative permeability of the magnetic layer is set to 2.0 or higher at a frequency of 2 GHz. Therefore, in the relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of shielding attenuation in the frequency range of 2 to 3 GHz can be set to 5 dB or less. This makes it possible to provide a shielded cable with stable electromagnetic noise shielding function.

[0018] Furthermore, in the shielded cable of this embodiment, it is preferable to set the thickness of the magnetic layer to less than 200 μm. When using a soft magnetic powder with a low imaginary part of relative permeability for the magnetic layer, if the thickness of the magnetic layer is thin, it is not possible to suppress fluctuations in the shielding attenuation even if the packing density of the soft magnetic powder within the magnetic layer is increased. However, by increasing the thickness of the magnetic layer, it is possible to suppress fluctuations in the shielding attenuation even when using a soft magnetic powder with a low imaginary part of relative permeability. That is, by increasing the thickness of the magnetic layer, the amount of magnetic powder particles that can pass through the magnetic layer to transmit electromagnetic noise that has entered the magnetic layer increases, and fluctuations in the shielding attenuation can be suppressed even in a magnetic layer using a material with a low imaginary part of relative permeability. However, when the magnetic layer is thickened, the overall diameter of the cable increases, the overall weight of the cable increases, and the flexibility of the cable decreases. Furthermore, when the overall diameter of the cable increases, there is also the problem that it will not match the size of the connectors that are connected to both ends of the cable. Therefore, by reducing the thickness of the magnetic layer to less than 200 μm, it is possible to provide a shielded cable that has stable electromagnetic noise shielding functionality with minimal fluctuations in electromagnetic noise shielding performance in a specific frequency band, while suppressing an increase in the overall diameter and weight of the shielded cable.

[0019] Furthermore, in the shielded cable of this embodiment, it is preferable that the imaginary part of the relative permeability of the magnetic layer be 1.5 or more at a frequency of 3 GHz.

[0020] The shielded cables of this embodiment include coaxial cables, twisted-pair cables, multi-core cables, etc. In particular, coaxial cables are used as communication cables for transmitting high-frequency signals and are used for video cable applications. Below, a coaxial cable, which is one of the shielded cables of this embodiment, will be described with reference to the drawings.

[0021] (Embodiment 1) Figure 1 is a schematic cross-sectional view of a coaxial cable according to Embodiment 1. The coaxial cable 10 comprises, from the inside out, an internal conductor 11, an insulating layer 12, a metal layer 13, a metal braided body 14, an electromagnetic noise shielding layer 15, and an outer covering layer 16. The coaxial cable 10 has a double shield structure with the internal conductor 11 (internal conductor), a metal layer 13 (first outer conductor), and a metal braided body 14 (second outer conductor). The electromagnetic noise shielding layer 15 is configured as a laminate formed by stacking a base material layer 15a and a magnetic layer 15b arranged on one side of the base material layer 15a.

[0022] In Figure 1, the base layer 15a of the electromagnetic noise shielding layer 15 is positioned on the axial side, but the magnetic layer 15b may also be positioned on the axial side.

[0023] The electromagnetic noise shielding layer 15 is usually formed as a tape-like sheet, and is incorporated into the coaxial cable 10 by wrapping this tape-like sheet around the outer surface of a cable-like laminate consisting of an internal conductor 11, an insulating layer 12, a metal layer 13, and a metal braid 14.

[0024] Furthermore, the magnetic layer 15b of the electromagnetic noise shielding layer 15 includes a soft magnetic material and a resin, and the imaginary part of the relative permeability of the magnetic layer 15b is set to 2.0 or higher at a frequency of 2 GHz. As a result, in the coaxial cable 10, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz can be made 5 dB or less in the relationship diagram between the shielding attenuation and frequency measured in accordance with IEC 62153-4. This makes it possible to realize a coaxial cable 10 with small fluctuations in electromagnetic noise shielding performance in a specific frequency band and a stable electromagnetic noise shielding function.

[0025] The electromagnetic noise shielding layer of the above-mentioned coaxial cable will be explained in detail below.

[0026] [Electromagnetic Noise Shielding Layer] The electromagnetic noise shielding layer of this embodiment is configured as a laminate formed by laminating a base material and a magnetic layer. The overall thickness of the electromagnetic noise shielding layer is preferably 30 μm to 220 μm, and more preferably 50 to 120 μm. If the overall thickness of the electromagnetic noise shielding layer is too thin, the thickness of the magnetic layer will also be thin, reducing the electromagnetic noise shielding performance and the strength of the electromagnetic noise shielding layer. On the other hand, if the overall thickness of the electromagnetic noise shielding layer is too thick, flexibility will decrease, making it difficult to wrap around a cable. Also, the overall diameter of the cable will increase, the weight will increase, and the flexibility will decrease. Within the range in which the effects of this embodiment can be achieved, the electromagnetic noise shielding layer may include layers other than the magnetic layer and the base material.

[0027] <Magnetic Layer> The magnetic layer contains a soft magnetic material and a resin. As mentioned above, the thickness of the magnetic layer is preferably less than 200 μm. If the thickness of the magnetic layer is 200 μm or more, the flexibility of the magnetic layer decreases, the overall diameter of the cable increases, the weight increases, and it tends to become difficult to wrap around the cable. Furthermore, from the viewpoint of reducing the weight of the cable, the thickness of the magnetic layer is more preferably 60 μm or less. On the other hand, if the thickness of the magnetic layer is too thin, the electromagnetic noise shielding performance decreases, so it is usually preferable to set it to 10 μm or more. That is, the thickness of the magnetic layer is preferably 10 μm or more and less than 200 μm, and more preferably 10 μm or more and 60 μm or less.

[0028] Furthermore, the arithmetic mean roughness Ra of the magnetic layer surface is preferably 0.5 μm or more and 3.0 μm or less. When Ra is within the above range, the surface of the magnetic layer has an appropriate roughness, the sliding effect of the magnetic layer surface is improved, and the sliding durability of the magnetic layer when wrapped around a cable is improved.

[0029] The imaginary part of the relative permeability of the magnetic layer described above is set to 2.0 or higher at a frequency of 2 GHz. As a result, in the relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz can be made to 5 dB or less, thereby suppressing the fluctuation of the shielding attenuation of the coaxial cable of this embodiment with respect to the measurement frequency.

[0030] The imaginary part of the relative permeability of the above magnetic layer (ε r The imaginary part (ε) of the relative permeability was measured in accordance with IEC 60556-2006. Specifically, the imaginary part (ε) of the relative permeability was measured. r The measurement was performed by connecting an Anritsu Corporation vector network analyzer "MS46122B-043" and a Keycom Corporation high-frequency magnetic material measurement system "PER01" with a 3m coaxial cable "MWX051-03000KFSKMS / B" manufactured by Junko Co., Ltd.

[0031] The above vector network analyzer was pre-calibrated using SOLT (Short-Open-Load-Thru) and measured using Keycom's analysis software "DMP-PWR01-03A Measurement Software". The frequency range was 0.01 GHz to 10 GHz, and measurement points were set using 401 logarithmic scaling points to measure the imaginary part (ε) of the relative permeability of the magnetic layer. r The imaginary part of the relative permeability (ε) was measured. r The value was calculated as the average of 11 measurements, with five points before and five points after the measurement point closest to the frequency of 2 GHz and 3 GHz, respectively.

[0032] Furthermore, the shielding attenuation of the above cable was measured in accordance with IEC 62153-4. Specifically, the measurement was performed by connecting an Anritsu Corporation vector network analyzer "MS46122B-043" to bda connectivity's CoMeT Test System "CoMeT40". The vector network analyzer was pre-calibrated using SOLT (Short-Open-Load-Thru) and measured using bda connectivity's analysis software "WinCoMeT software". The cable length measured was 1m, the frequency range was 0.01GHz to 10GHz, and measurement points were set up with 801 logarithmic scaling points to measure the shielding attenuation (unit: dB). The standard deviation was calculated between measurement points with frequencies closest to 2 GHz and 3 GHz, respectively.

[0033] The imaginary part of the relative permeability of the magnetic layer described above is preferably 2.0 or more and 3.0 or less at a frequency of 2 GHz. Within this range, in the relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz can be made 2 dB or less, which can more effectively suppress the fluctuation of the shielding attenuation of the coaxial cable of this embodiment with respect to the measurement frequency, and a more stable electromagnetic noise shielding effect can be obtained. Furthermore, the imaginary part of the relative permeability of the magnetic layer described above is more preferably 2.4 or more and 3.0 or less at a frequency of 2 GHz. As a result, in the relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4 described above, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz can be made 1.8 dB or less, which can further effectively suppress the fluctuation of the shielding attenuation of the coaxial cable of this embodiment with respect to the measurement frequency, and an extremely stable electromagnetic noise shielding effect can be obtained. Furthermore, the lower limit of the standard deviation is usually 1.2 dB or higher.

[0034] Specifically, the imaginary part of the relative permeability of the magnetic layer is preferably 2.0 or more and 3.0 or less at a frequency of 2 GHz, and in the relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz is preferably 2 dB or less. More preferably, the imaginary part of the relative permeability of the magnetic layer is preferably 2.4 or more and 3.0 or less at a frequency of 2 GHz, and in the relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz is preferably 1.2 dB or more and 1.8 dB or less.

[0035] [Soft Magnetic Material] In this embodiment, a soft magnetic material is used as the magnetic material. Soft magnetic materials have a high initial magnetic permeability and can exhibit electromagnetic noise shielding performance even when included in small amounts in the magnetic layer, so the electromagnetic noise shielding effect can be achieved even when the magnetic layer is made into a thin film.

[0036] Examples of the above soft magnetic materials include iron, carbonyl iron powder, silicon iron, Fe-Ni alloy, Fe-Si-Al alloy, Fe-Co alloy, soft ferrite, ferritic stainless steel, electromagnetic stainless steel, amorphous magnetic alloy, nanocrystal magnetic alloy, etc., but Fe(CO) is particularly noteworthy as a soft magnetic material. ５ Carbonyl iron powder or Fe-Si-Al alloy is preferred. This is because carbonyl iron powder and Fe-Si-Al alloy can exhibit electromagnetic wave absorption performance (electromagnetic noise suppression effect) even in relatively high frequency ranges such as the GHz band.

[0037] The above-mentioned soft magnetic material is usually provided as a spherical or flattened powder, but the powder of the soft magnetic material may also be granular (irregular shape), needle-shaped, etc. The average particle diameter is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less. If the average particle diameter of the soft magnetic material is too small, the particles tend to aggregate secondarily, making it difficult to obtain a uniform coating film (magnetic layer). On the other hand, if the average particle diameter is too large, the particles tend to protrude from the magnetic layer as protrusions, making it easy for the magnetic layer to peel off the substrate when the electromagnetic noise shielding layer is wrapped around a cable. The above-mentioned average particle diameter can be measured with a laser diffraction scattering particle size distribution analyzer.

[0038] The above soft magnetic material preferably uses flattened soft magnetic powder. Using flattened soft magnetic powder improves the packing of the magnetic layer, increases the imaginary part of the relative permeability of the magnetic layer, and suppresses fluctuations in the shielding attenuation.

[0039] The volume content of the soft magnetic material contained in the magnetic layer is preferably 25% by volume or more and 70% by volume or less, and more preferably 35% by volume or more and 60% by volume or less. If the volume content falls below 25% by volume, the amount of soft magnetic material decreases, and the magnetic noise shielding performance of the magnetic layer deteriorates. If the volume content exceeds 70% by volume, the weight of the magnetic layer increases, and its flexibility decreases, making it difficult to wrap the electromagnetic noise shielding layer around the cable.

[0040] [Resin] The resin used in the magnetic layer functions as a binder that holds and fixes the soft magnetic material and adheres it to the substrate. At least one of thermoplastic resins, thermosetting resins, and rubber can be used as the resin. When forming a magnetic layer by applying a coating for forming a magnetic layer containing the soft magnetic material of this application onto a substrate, thermosetting resins or rubber are preferred. Furthermore, when mixing the soft magnetic material of this application with a resin, melting and extruding the mixture, and then attaching the substrate thereto, a thermoplastic resin is preferred. Furthermore, when mixing the soft magnetic material of this application with a resin, forming the mixture into a sheet by pressurizing and heating, and then attaching the substrate thereto, rubber can be used.

[0041] As the above-mentioned thermosetting resin, for example, phenolic resin, urea resin, melamine resin, epoxy resin, polyester resin, alkyd resin, silicone resin, polyurethane resin, acrylic resin, etc. can be used. It is preferable that these resins are crosslinked in the magnetic layer by adding a crosslinking agent. As the above-mentioned crosslinking agent, isocyanate or an epoxy group-containing compound can be used.

[0042] As the above-mentioned thermoplastic resin, for example, polyethylene, polypropylene, polystyrene, ABS resin, methyl methacrylate resin, polyvinyl chloride, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, etc. can be used.

[0043] As the above-mentioned rubber, for example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), nitrile rubber (NBR), ethylene-propylene rubber (EPDM), chloroprene rubber (CR), acrylic rubber (ACM), chlorosulfonated polyethylene rubber (CSR), urethane rubber (PUR), silicone rubber (Q), fluororubber (FKM), ethylene-vinyl acetate rubber (EVA), epichlorohydrin rubber (CO), polysulfide rubber (T), urethane rubber (U), etc. can be used.

[0044] Further, from another perspective, as the above-mentioned resin, a plurality of resins having different glass transition temperatures can be used. For example, it is preferable to include an amorphous resin (A) having a glass transition temperature of -50°C to 0°C and an amorphous resin (B) having a glass transition temperature of 10°C or higher. Since amorphous resins have high solubility in water and other solvents and excellent dispersibility of magnetic materials (magnetic powder), magnetic powder can be dispersed in a resin dissolved in water or other solvents, and then coated and dried on a substrate with an arbitrary thickness to form a magnetic layer into a sheet.

[0045] As the amorphous resin (A), an amorphous polyester, an amorphous polyurethane, an amorphous acrylic, etc. with a glass transition temperature of -50°C to 0°C can be used. As the amorphous resin (B), an amorphous polyester, an amorphous polyurethane, an amorphous acrylic, etc. with a glass transition temperature of 10°C or higher can be used. Among these, in particular, as the amorphous resin (A), an amorphous polyester (a) with a glass transition temperature of -50°C to 0°C is preferable, and as the amorphous resin (B), an amorphous polyester (b) with a glass transition temperature of 10°C or higher is preferable. Among amorphous resins, amorphous polyester is excellent in solubility and flexibility and is suitable for manufacturing a sheet-like magnetic layer.

[0046] From the above viewpoints, the content ratios of the amorphous polyester (a) and the amorphous polyester (b) are preferably (a):(b) = 95:5 to 35:65, more preferably (a):(b) = 90:10 to 50:50, in terms of the mass ratio of the solid content. The content ratios of the amorphous polyester (a) and (b) can be estimated to some extent from the intensities of the peaks of the two detected glass transition temperatures by measuring the glass transition temperature of the magnetic layer. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

[0047] Further, as another example of using a plurality of resins with different glass transition temperatures, an amorphous resin (A) with a glass transition temperature of -50°C to 0°C, an amorphous resin (B) with a glass transition temperature of 10°C or higher, and an amorphous resin (C) with a glass transition temperature greater than 0°C and lower than 10°C may be used in combination. As the amorphous resin (C), an amorphous polyester, an amorphous polyurethane, an amorphous acrylic, etc. with a glass transition temperature greater than 0°C and lower than 10°C can be used. Among these, an amorphous polyester (c) with a glass transition temperature greater than 0°C and lower than 10°C is preferable as the amorphous resin (C). By using these three types of resins in combination, the flexibility and hot melt property of the shielded cable can be improved. The content ratios of the amorphous polyester (a), the amorphous polyester (b), and the amorphous polyester (c) are preferably (a):(b):(c) = 20:40:4 to 60:20:20 in terms of the mass ratio of the solid content.

[0048] <Substrate> The substrate used in the electromagnetic noise shielding layer of this embodiment is a base material for forming the magnetic layer.

[0049] The above-mentioned substrate can be any material that is flexible and can ensure adhesion to the magnetic layer, and is usually a resin film. Examples of resins that make up the above-mentioned substrate include polyolefin resins (polyethylene, polypropylene, etc.), polyester resins (polyethylene terephthalate: PET, polyethylene naphthalate: PEN, polybutylene terephthalate: PBT, polybutylene naphthalate: PBN, etc.), polyimide resins, polyamide resins, ethylene-vinyl acetate copolymers, ionomer resins, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, ethylene-butene copolymers, ethylene-hexene copolymers, polyurethane resins, polyetherketone resins, polyether resins, polyethersulfone resins, polystyrene resins (polystyrene, etc.), polyvinyl chloride resins, polyvinylidene chloride resins, polyvinyl alcohol resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymers, polycarbonate resins, fluororesins, silicone resins, cellulose resins, and crosslinked products of these resins. Among these, polyethylene terephthalate (PET) is more preferred in terms of mechanical properties and cost. One or more of these resin materials can be used. Furthermore, the above resin materials may have functional groups as needed. Functional monomers or modifier monomers may also be grafted onto the resin material.

[0050] Furthermore, the resin constituting the above-mentioned resin film may contain, if necessary, known auxiliary agents such as fillers, flame retardants, degradation inhibitors, antistatic agents, softeners, and plasticizers.

[0051] The surface of the above-mentioned substrate may be subjected to known surface treatments to improve adhesion with adjacent magnetic layers. Specific examples of such surface treatments include corona discharge treatment, ozone exposure treatment, high-voltage electric shock exposure treatment, and ionization radiation treatment. Furthermore, the substrate may be subjected to coating treatments with undercoating agents (such as silicone treatment), primer treatment, matting treatment, crosslinking treatment, etc.

[0052] The above-mentioned substrate may be a single layer or a laminate of two or more layers. In the case of a laminate, a laminate of a metal layer (metal foil) and a resin film can be used. In this case, the electromagnetic noise shielding layer will include a substrate containing the metal layer and the resin film, and a magnetic layer. The magnetic layer may be placed on the metal layer side of the substrate or on the resin film side of the substrate.

[0053] The type of metal constituting the above metal layer is not particularly limited as long as it has some degree of flexibility, but aluminum, copper, permalloy, and their alloys are preferred. Among aluminum, soft aluminum and among copper, rolled copper are more preferred because they have high conductivity, are inexpensive, are easy to process into thin films, and have excellent flexibility. In addition, permalloy has high magnetic collection effect in the kHz range in addition to conductivity, and can also be used as a magnetic shield.

[0054] The thickness of the metal layer is preferably between 5 μm and 30 μm. If the thickness of the metal layer is less than 5 μm, the strength decreases, and if the thickness exceeds 30 μm, the metal layer becomes too thick, which increases the overall diameter of the cable, increases the overall weight of the cable, and reduces the flexibility of the cable. Furthermore, if the overall diameter of the cable becomes too large, it may not match the size of the connectors that are connected to both ends of the cable.

[0055] The thickness of the above-mentioned substrate is not particularly limited, but in the case of a single layer, it is preferably 5 to 20 μm, and more preferably 10 to 15 μm. In the case of a laminate consisting of two or more layers, it is preferably 10 to 50 μm, and more preferably 15 to 40 μm. If the thickness of the above-mentioned substrate is within the above range, both the strength and flexibility of the electromagnetic noise shielding layer of this embodiment can be achieved.

[0056] Next, we will describe the components of the coaxial cable other than the electromagnetic noise shielding layer. However, a detailed description of these components is disclosed in Patent Document 2 (Japanese Patent Application Publication No. 2022-108557), so we will only briefly describe each of these components here.

[0057] [Internal Conductors] The internal conductors mentioned above, also called core wires or core wires, are internal conductors composed of perfectly circular wires, usually made of soft copper for electrical use, and radio waves (signals) are transmitted around these internal conductors.

[0058] [Insulating Layer] The insulating layer described above is placed between the internal wire (internal conductor) and the metal layer (outer conductor), and is an insulator made of resin material or the like. It has the function of electrically insulating the internal conductor from the outer conductor, as well as the function of holding and protecting the internal conductor.

[0059] [Metal Layer] The above-mentioned metal layer is a first outer conductor formed of aluminum foil or the like, and has the function of preventing radio waves (signals) transmitted through the inner conductor from leaking to the outside as noise, as well as the function of preventing external noise from entering the inner conductor.

[0060] [Metal Braid] The above-mentioned metal braid is a second outer conductor formed by twisting conductors into a mesh, and, similar to the above-mentioned metal layer (first outer conductor), has the function of preventing radio waves (signals) transmitted through the inner conductor from leaking to the outside as noise, and also has the function of preventing external noise from entering the inner conductor. The above-mentioned metal braid can further suppress the leakage of internal noise and the intrusion of external noise, and can also provide flexibility to the cable.

[0061] [Outer Sheath Layer] The outer sheath layer, also known as the sheath layer, consists of an insulator made of resin material or the like, and constitutes the outermost layer of the coaxial cable. The outer sheath layer has the function of protecting the entire cable and maintaining its shape.

[0062] (Embodiment 2) Figure 2 is a schematic cross-sectional view of the coaxial cable of Embodiment 2. The coaxial cable 20 comprises, from the inside out, an internal conductor 11, an insulating layer 12, a first metal layer 13, a metal braid 14, a second metal layer 17, an electromagnetic noise shielding layer 15, and an outer covering layer 16. The coaxial cable 20 of Embodiment 2 has a structure in which the second metal layer 17 is further added to the coaxial cable 10 of Embodiment 1 shown in Figure 1, so the explanation of the components that overlap with Embodiment 1 will be omitted.

[0063] The coaxial cable 20 has a triple-shielded structure comprising an internal conductor 11, a first metal layer 13 (first outer conductor), a metal braid 14 (second outer conductor), and a second metal layer 17 (third outer conductor). The triple-shielded structure of Embodiment 2 can further improve electromagnetic noise shielding performance compared to the double-shielded structure of Embodiment 1.

[0064] <Second Metal Layer> The second metal layer is usually made of metal foil, and the type of metal that makes up the metal foil is not particularly limited as long as it has some degree of flexibility, but aluminum, copper, and alloys thereof are preferred. Among aluminum, soft aluminum and among copper, rolled copper are more preferred because they have high conductivity, are inexpensive, are easy to process into thin films, and have excellent flexibility. The second metal layer may also be magnetic.

[0065] The thickness of the second metal layer is not particularly limited, but if it is too thick, the flexibility will decrease, so it is usually set in the range of 5 to 30 μm, and 7 to 15 μm is more preferred.

[0066] (Embodiment 3) Figure 3 is a schematic cross-sectional view of the coaxial cable of Embodiment 3. The coaxial cable 30 comprises, from the inside out, an internal conductor 11, an insulating layer 12, a metal braided body 14, an electromagnetic noise shielding layer 15, and an outer covering layer 16, in that order. The coaxial cable 30 of Embodiment 3 has a structure in which the metal layer 13 is removed from the coaxial cable 10 of Embodiment 1 shown in Figure 1, so the explanation of the components that overlap with Embodiment 1 will be omitted.

[0067] The coaxial cable 30 has a single-shielded structure with a metal braided body 14 (outer conductor) surrounding the internal conductor 11 (internal wire). The single-shielded structure of Embodiment 3 can exhibit the electromagnetic noise shielding performance required depending on the application.

[0068] The present application will be described in detail below using examples. However, the present application is not limited to the following examples. Unless otherwise specified, "parts" below means "parts by mass".

[0069] (Example 1) <Preparation of magnetic layer forming coating> Magnetic layer forming coating A was prepared by mixing and dispersing the following components. (1) Soft magnetic material (spherical carbonyl iron powder manufactured by Tenichi Co., Ltd., trade name "YW-3"): 70.6 parts (2) Amorphous polyester resin solution (a) (manufactured by Toyobo MC Co., Ltd., trade name "Byron BX-10AS", resin Tg: -18°C, solids concentration: 40% by mass, solvent: methyl ethyl ketone): 5.7 parts (3) Amorphous polyester resin solution (b) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 630", resin Tg: 7°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 5.0 parts (4) Amorphous polyester resin solution (c) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 200", resin Tg: 67°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 12.6 parts (5) Crosslinking agent (polyisocyanate for paints / non-yellowing type, manufactured by Tosoh Corporation, trade name "Coronate® HX"): 0.2 parts (6) Solvent (methyl ethyl ketone): 5.9 parts

[0070] In the above-mentioned magnetic layer forming coating A, the content ratio of amorphous polyesters (a), (b), and (c) was (a):(b):(c) = 30:20:50 in terms of solid content mass ratio, and the volume content of the soft magnetic material relative to the total solid content of the magnetic layer forming coating A was 58.3% by volume.

[0071] <Formation of Magnetic Layer> Next, a PET film with a thickness of 12 μm (manufactured by Toyobo Co., Ltd., product name "Toyobo Ester® Film E5100") was used as a substrate. The magnetic layer forming coating A was applied to one main surface of the substrate using a comma direct coating so that the thickness of the magnetic layer after calendering would be 190 μm, and it was dried at 120°C. Subsequently, the raw material roll was calendered at a temperature of 80°C and a linear pressure of 300 kg / cm using a calendering device with a metal roll, thereby producing an electromagnetic noise suppression sheet in which a magnetic layer was formed on one main surface of the substrate.

[0072] <Formation of Coaxial Cable> The obtained electromagnetic noise suppression sheet was slit to a width of 9 mm, and the electromagnetic noise suppression sheet was wrapped around the outer circumference of a cable-like laminate with an outer diameter of 2.3 mm, consisting of an internal conductor, an insulating layer, a metal layer, and a metal braid, as an electromagnetic noise shielding layer, with the base material positioned on the central axis side, and an outer covering layer (outer sheath) was formed by extruding resin around the outer circumference to form the coaxial cable of Example 1.

[0073] (Example 2) The following components were mixed and dispersed to prepare coating B for forming a magnetic layer. (1) Soft magnetic material (spherical carbonyl iron powder manufactured by Tenichi Co., Ltd., trade name "YW-3"): 43.1 parts (2) Amorphous polyester resin solution (a) (manufactured by Toyobo MC Co., Ltd., trade name "Byron BX-10AS", resin Tg: -18°C, solids concentration: 40% by mass, solvent: methyl ethyl ketone): 8.1 parts (3) Amorphous polyester resin solution (b) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 630", resin Tg: 7°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 7.2 parts (4) Amorphous polyester resin solution (c) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 200", resin Tg: 67°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 18.0 parts (5) Crosslinking agent (polyisocyanate for paints / non-yellowing type, manufactured by Tosoh Corporation, trade name "Coronate® HX"): 0.2 parts (6) Solvent (methyl ethyl ketone): 23.3 parts

[0074] The volume content of the soft magnetic material relative to the total solid content of the magnetic layer-forming coating B described above was 38.8% by volume. The content ratios of amorphous polyesters (a), (b), and (c) were the same as in Example 1.

[0075] <Formation of Magnetic Layer> Next, an electromagnetic noise suppression sheet was prepared in the same manner as in Example 1, except that the magnetic layer-forming coating B described above was used, with a magnetic layer formed on one main surface of the substrate. The thickness of the magnetic layer was 60 μm.

[0076] <Formation of coaxial cable> The coaxial cable of Example 2 was formed in the same manner as in Example 1, except that the above-mentioned electromagnetic noise suppression sheet was used as an electromagnetic noise shielding layer.

[0077] (Example 3) A magnetic layer-forming coating C was prepared by mixing and dispersing the following components. (1) Soft magnetic material (flat Fe-Si-Al iron powder manufactured by Sanyo Special Steel Co., Ltd., trade name "FME3D-AH"): 40.1 parts (2) Amorphous polyester resin solution (a) (manufactured by Toyobo MC Co., Ltd., trade name "Byron BX-10AS", resin Tg: -18°C, solids concentration: 40% by mass, solvent: methyl ethyl ketone): 8.6 parts (3) Amorphous polyester resin solution (b) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 630", resin Tg: 7°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 7.6 parts (4) Amorphous polyester resin solution (c) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 200", resin Tg: 67°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 19.0 parts (5) Crosslinking agent (polyisocyanate for paints / non-yellowing type, manufactured by Tosoh Corporation, trade name "Coronate® HX"): 0.2 parts (6) Solvent (methyl ethyl ketone): 24.5 parts

[0078] The volume content of the soft magnetic material relative to the total solid content of the magnetic layer-forming coating C described above was 39.6% by volume. The content ratios of amorphous polyesters (a), (b), and (c) were the same as in Example 1.

[0079] <Formation of Magnetic Layer> Next, an electromagnetic noise suppression sheet was prepared in the same manner as in Example 1, except that the magnetic layer-forming coating C described above was used, with a magnetic layer formed on one main surface of the substrate. The thickness of the magnetic layer was 40 μm.

[0080] <Formation of coaxial cable> The coaxial cable of Example 3 was formed in the same manner as in Example 1, except that the above-mentioned electromagnetic noise suppression sheet was used as an electromagnetic noise shielding layer.

[0081] (Example 4) The coaxial cable of Example 4 was formed in the same manner as in Example 3, except that the thickness of the magnetic layer of the electromagnetic noise suppression sheet (electromagnetic noise shielding layer) was changed to 20 μm.

[0082] (Example 5) An aluminum foil / PET composite film (manufactured by Daido Chemical Co., Ltd., product name "Alpet #1012") made by laminating a 10 μm thick aluminum foil and a 12 μm thick PET film was used as the base material. The magnetic layer forming coating C prepared in Example 3 was applied to the PET surface of the base material in a comma direct application manner so that the thickness of the magnetic layer after calendering would be 40 μm, and it was dried at 100°C. Subsequently, an electromagnetic noise suppression sheet was produced in which a magnetic layer was formed on the PET surface by calendering the raw material roll at a temperature of 80°C and a linear pressure of 300 kg / cm using a calendering device with a metal roll.

[0083] <Formation of Coaxial Cable> The coaxial cable of Example 5 was formed in the same manner as in Example 1, except that the above-mentioned electromagnetic noise suppression sheet was used as an electromagnetic noise shielding layer and the aluminum foil was positioned on the central axis side (so that the metal braid and the aluminum foil were in contact).

[0084] (Example 6) The coaxial cable of Example 6 was formed in the same manner as in Example 1, except that the thickness of the magnetic layer of the electromagnetic noise suppression sheet (electromagnetic noise shielding layer) was changed to 200 μm.

[0085] (Comparative Example 1) A magnetic layer-forming coating D was prepared by mixing and dispersing the following components. (1) Soft magnetic material (Ni-Zn ferrite powder manufactured by Toda Kogyo Co., Ltd., trade name "BSN-714"): 49.8 parts (2) Amorphous polyester resin solution (a) (manufactured by Toyobo MC Co., Ltd., trade name "Byron BX-10AS", resin Tg: -18°C, solids concentration: 40% by mass, solvent: methyl ethyl ketone): 7.5 parts (3) Amorphous polyester resin solution (b) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 630", resin Tg: 7°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 6.6 parts (4) Amorphous polyester resin solution (c) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 200", resin Tg: 67°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 16.6 parts (5) Crosslinking agent (polyisocyanate for paints / non-yellowing type, manufactured by Tosoh Corporation, trade name "Coronate® HX"): 0.3 parts (6) Solvent (methyl ethyl ketone): 19.3 parts

[0086] The volume content of the soft magnetic material relative to the total solid content of the magnetic layer-forming coating D was 53.4% ​​by volume. The content ratios of amorphous polyesters (a), (b), and (c) were the same as in Example 1.

[0087] <Formation of Magnetic Layer> Next, an electromagnetic noise suppression sheet was prepared in the same manner as in Example 1, except that the magnetic layer-forming coating D described above was used, with a magnetic layer formed on one main surface of the substrate. The thickness of the magnetic layer was 190 μm.

[0088] <Formation of Coaxial Cable> A coaxial cable of Comparative Example 1 was formed in the same manner as in Example 1, except that the above-mentioned electromagnetic noise suppression sheet was used as an electromagnetic noise shielding layer.

[0089] (Comparative Example 2) A magnetic layer-forming coating E was prepared by mixing and dispersing the following components. (1) Soft magnetic material (Ni-Zn ferrite powder manufactured by Toda Kogyo Co., Ltd., trade name "BSN-714"): 7.0 parts (2) Amorphous polyester resin solution (a) (manufactured by Toyobo MC Co., Ltd., trade name "Byron BX-10AS", resin Tg: -18°C, solids concentration: 40% by mass, solvent: methyl ethyl ketone): 20.5 parts (3) Amorphous polyester resin solution (b) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 630", resin Tg: 7°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 18.2 parts (4) Amorphous polyester resin solution (c) (manufactured by Toyobo MC Co., Ltd., trade name "Byron 200", resin Tg: 67°C, solids concentration: 30% by mass, solvent: methyl ethyl ketone): 45.5 parts (5) Crosslinking agent (polyisocyanate for paints / non-yellowing type, manufactured by Tosoh Corporation, trade name "Coronate® HX"): 0.7 parts (6) Solvent (methyl ethyl ketone): 2.0 parts

[0090] The volume content of the soft magnetic material relative to the total solid content of the magnetic layer-forming coating E was 3.7% by volume. The content ratios of amorphous polyesters (a), (b), and (c) were the same as in Example 1.

[0091] <Formation of Magnetic Layer> Next, an electromagnetic noise suppression sheet was prepared in the same manner as in Example 1, except that the magnetic layer-forming coating E described above was used, with a magnetic layer formed on one main surface of the substrate. The thickness of the magnetic layer was 240 μm.

[0092] <Formation of Coaxial Cable> The coaxial cable of Comparative Example 2 was formed in the same manner as in Example 1, except that the above-mentioned electromagnetic noise suppression sheet was used as an electromagnetic noise shielding layer.

[0093] (Comparative Example 3) A coaxial cable of Comparative Example 3 was formed in the same manner as in Example 1, except that an electromagnetic noise shielding layer made of an electromagnetic noise suppression sheet was not incorporated into the cable.

[0094] For the coaxial cables of Examples 1 to 6 and Comparative Examples 1 to 3 described above, the imaginary part of the relative permeability of the magnetic layer at a frequency of 2 GHz, and the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz were measured using the method described above. However, since there was no magnetic layer in Comparative Example 3, the measurement of the imaginary part of the relative permeability was not performed.

[0095] Furthermore, the ratio (%) of the diameter and weight of the other coaxial cables was calculated, assuming that the diameter of the coaxial cable of Comparative Example 3, which did not incorporate an electromagnetic noise shielding layer, was 100%, and the weight of the coaxial cable of Comparative Example 3 was also 100%.

[0096] Table 1 shows the type of magnetic material and substrate used and the thickness of the magnetic layer for Examples 1 to 6 and Comparative Examples 1 to 3 described above. Table 2 shows the standard deviation of the amplitude of the relative permeability imaginary part and shielding attenuation of the magnetic layer measured above, as well as the ratio of the cable diameter and weight calculated above.

[0097]

[0098]

[0099] Tables 1 and 2 show that in Examples 1 to 6, where the imaginary part of the relative permeability of the magnetic layer was 2.0 or higher at a frequency of 2 GHz, the relationship diagram between shielding attenuation and frequency, measured in accordance with IEC 62153-4, showed that the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz was 5 dB or less. This demonstrated that the fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz was small, and a shielded cable with stable electromagnetic noise shielding functionality was realized. Furthermore, in Examples 1 to 5, where the thickness of the magnetic layer was less than 200 μm, in addition to stable electromagnetic noise shielding functionality, the cable diameter was increased to a maximum of 110% and the cable weight to a maximum of 150% compared to Comparative Example 3, which did not incorporate an electromagnetic noise shielding layer. Thus, a shielded cable with suppressed increases in cable diameter and cable weight was also realized.

[0100] On the other hand, in Comparative Examples 1 and 2, where the imaginary part of the relative permeability of the magnetic layer was less than 2.0 at a frequency of 2 GHz, the standard deviation of the amplitude of the shielding attenuation in the frequency range of 2 to 3 GHz exceeded 5 dB, indicating large fluctuations in the shielding attenuation. Furthermore, in Comparative Example 3, which did not incorporate an electromagnetic noise shielding layer, the standard deviation of the amplitude of the shielding attenuation in the frequency range of 2 to 3 GHz also exceeded 5 dB, indicating large fluctuations in the shielding attenuation.

[0101] Because the shielded cable of this invention is lightweight and has a small diameter, it can be wired to the finer details of electronic equipment. Examples of such electronic equipment include precision measuring devices, automotive parts, and computer equipment. As a result, it is possible to realize electronic equipment that is less susceptible to electromagnetic noise.

[0102] With respect to embodiments of the present application including the above-described examples 1 to 6, the following additional embodiments are further disclosed. (Additional Embodiment 1) A shielded cable including an electromagnetic noise shielding layer, wherein the electromagnetic noise shielding layer is a laminate including a base material and a magnetic layer, the magnetic layer includes a soft magnetic material and a resin, the imaginary part of the relative permeability of the magnetic layer is 2.0 or more at a frequency of 2 GHz, and in a relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz is 5 dB or less. (Additional Embodiment 2) The shielded cable according to Additional Embodiment 1, wherein the thickness of the magnetic layer is less than 200 μm. (Additional Embodiment 3) The shielded cable according to Additional Embodiment 1, wherein the thickness of the magnetic layer is 60 μm or less. (Additional Embodiment 4) The shielded cable according to Additional Embodiment 1, wherein the thickness of the magnetic layer is 10 μm or more and less than 200 μm. (Appendix 5) The shielded cable according to Appendix 1, wherein the thickness of the magnetic layer is 10 μm or more and 60 μm or less. (Appendix 6) The shielded cable according to any of Appendix 1 to 5, wherein the thickness of the electromagnetic noise shielding layer is 30 μm or more and 220 μm or less. (Appendix 7) The shielded cable according to any of Appendix 1 to 6, wherein the soft magnetic material has a flattened shape. (Appendix 8) The shielded cable according to any of Appendix 1 to 7, wherein the volume content of the soft magnetic material contained in the magnetic layer is 25 volume% or more and 70 volume% or less. (Appendix 9) The shielded cable according to any of Appendix 1 to 8, wherein the base material is a resin film. (Appendix 10) The shielded cable according to any of Appendix 1 to 9, further comprising a metal layer on the side of the electromagnetic noise shielding layer opposite to the magnetic layer relative to the base material. (Appendix form 11) A shielded cable according to any of the appendix forms 1 to 10, comprising, from the inside out, an internal conductor, an insulating layer, a metal layer, a metal braid, the electromagnetic noise shielding layer, and an outer covering layer, in this order. (Appendix form 12) A shielded cable according to any of the appendix forms 1 to 10, comprising, from the inside out, an internal conductor, an insulating layer, a first metal layer, a metal braid, a second metal layer, the electromagnetic noise shielding layer, and an outer covering layer, in this order.(Appendix form 13) A shielded cable according to any of the appendix forms 1 to 10, comprising, from the inside out, an internal conductor, an insulating layer, a metal braided body, the electromagnetic noise shielding layer, and an outer covering layer in this order. (Appendix form 14) An electronic device characterized by including a shielded cable according to any of the appendix forms 1 to 13.

[0103] This application can also be implemented in forms other than those described above. The embodiments disclosed herein are examples and are not limiting. The scope of this application shall be interpreted in accordance with the claims attached, which take precedence over the description in the above specification, and all modifications within the scope equivalent to the claims shall be included in the claims.

[0104] 10, 20, 30 Coaxial cable 11 Internal conductor 12 Insulation layer 13 Metal layer (first metal layer) 14 Metal braid 15 Electromagnetic noise shielding layer 15a Base layer 15b Magnetic layer 16 Outer covering layer 17 Second metal layer

Claims

1. A shielded cable comprising an electromagnetic noise shielding layer, wherein the electromagnetic noise shielding layer is a laminate comprising a base material and a magnetic layer, the magnetic layer comprises a soft magnetic material and a resin, the imaginary part of the relative permeability of the magnetic layer is 2.0 or more at a frequency of 2 GHz, and in a relationship diagram between shielding attenuation and frequency measured in accordance with IEC 62153-4, the standard deviation of the amplitude of the periodic amplitude fluctuation of the shielding attenuation in the frequency range of 2 to 3 GHz is 5 dB or less.

2. The shielded cable according to claim 1, wherein the thickness of the magnetic layer is less than 200 μm.

3. The shielded cable according to claim 1, wherein the thickness of the magnetic layer is 60 μm or less.

4. The shielded cable according to claim 1, wherein the thickness of the magnetic layer is 10 μm or more and less than 200 μm.

5. The shielded cable according to claim 1, wherein the thickness of the magnetic layer is 10 μm or more and 60 μm or less.

6. The shielded cable according to claim 1, wherein the thickness of the electromagnetic noise shielding layer is 30 μm or more and 220 μm or less.

7. The shielded cable according to claim 1, wherein the soft magnetic material has a flattened shape.

8. The shielded cable according to claim 1, wherein the volume content of the soft magnetic material contained in the magnetic layer is 25% by volume or more and 70% by volume or less.

9. The shielded cable according to claim 1, wherein the base material is a resin film.

10. The shielded cable according to claim 1, further comprising a metal layer on the side of the electromagnetic noise shielding layer opposite to the magnetic layer relative to the substrate.

11. A shielded cable according to any one of claims 1 to 10, comprising, from the inside out, an internal conductor, an insulating layer, a metal layer, a metal braided body, the electromagnetic noise shielding layer, and an outer covering layer, in this order.

12. A shielded cable according to any one of claims 1 to 10, comprising, from the inside out, an internal conductor, an insulating layer, a first metal layer, a metal braid, a second metal layer, the electromagnetic noise shielding layer, and an outer covering layer, in this order.

13. A shielded cable according to any one of claims 1 to 10, comprising, from the inside out, an internal conductor, an insulating layer, a metal braided body, the electromagnetic noise shielding layer, and an outer covering layer, in this order.

14. Electronic device comprising a shielded cable according to any one of claims 1 to 10.

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