Cable and antenna equipment with coaxial cable

Abstract

The cable includes a first shielding part, which includes at least one or more wires for transmitting signals or power and is arranged on the outside of the wires, a first layer, which is arranged to cover the outer periphery of the first shielding part and includes a component for absorbing radio waves, a second shielding part, which is arranged on the outside of the first layer; a second layer, which is arranged to cover the outer periphery of the second shielding part and includes a component for absorbing radio waves; and an insulating resin covering the outside of the second layer.

Description

Technical Field

[0001] The present technology relates to a power cable, a coaxial cable for transmitting television RF signals, a cable suitable for differential serial transmission standards such as USB (Universal Serial Bus) or HDMI (registered trademark) (High-Definition Multimedia Interface), and an antenna device with a coaxial cable. Background Art

[0002] Conventional coaxial cables connected to and used with balanced antennas cause various problems because the shielding wire of the outer conductor is connected to the ground of the device (such as a television receiver) to be connected to the coaxial cable. One of the problems is that the high-frequency current caused by the characteristic impedance mismatch of the coaxial cable connected to the antenna flows to the outer coating of the coaxial cable and affects the radiation characteristics of the antenna. Another problem is that when the coaxial cable is not properly connected to the ground of the device to be connected to the coaxial cable, such as in a pigtail, the noise of the device flows to the outer coating of the coaxial cable, and depending on the length of the coaxial cable, the outer coating of the coaxial cable acts as an antenna and radiates radio waves. In addition, there is a problem that, depending on the device to be connected to the coaxial cable, common mode or normal mode noise enters the outer coating or core wire of the coaxial cable due to the influence of the noise emitted from the device.

[0003] Usually, in order to solve the former problem described above, a spertopf antenna (spertopf) providing high impedance in the desired frequency is provided in the antenna or a balanced-unbalanced converter (balun) is used. And in order to solve the latter problem, the connection around the connector is properly established on the entire periphery to prevent such a situation as described above. In the case where there is still a problem even with this countermeasure, a ferrite core is wound around the connector side root of the coaxial cable to prevent current from flowing to the shielding wire outer coating of the coaxial cable. On the other hand, when the coaxial cable is placed in a portable device such as a smart phone, the outer coating of the coaxial cable is peeled off, and the coaxial cable is connected to the ground of the device to prevent current from flowing to the shielding wire outer coating of the coaxial cable.

[0004] This technology aims to solve the problem that performance cannot be demonstrated due to the influence of high-frequency current flowing to the cable and noise radiated from the device caused by connecting the cable to the device. In short, high-frequency current is prevented from flowing to the outer coating of the cable, thereby suppressing the influence of noise from the device.

[0005] For noise suppression in the cable used, for example, in the USB standard (USB cable), a technique such as disclosed in PTL 1 is known. The USB cable includes four wires, which include a set of differential data lines, a power line, and a ground line. Generally, in order to suppress noise to be emitted from the cable to the outside and electromagnetic waves entering the cable from the outside, a shielding layer woven with copper wire is provided. The shielding layer is connected to its end opposite to the ground potential portion.

[0006] However, the USB cable has a problem that the effect of electromagnetic shielding becomes insufficient when the ground potential is unreliable. The USB cable has another problem that when the ground potentials of two devices connected to each other are not equal to each other, current flows through the shielding layer and noise is transmitted to these devices. Furthermore, as a measure against this problem, it has been proposed to use a resin mixed with a radio wave absorbing material such as ferrite for a covering material for covering the shielding layer to suppress noise. In addition, a noise suppression member such as an inductor is provided at the cable connection portion where the cable is connected to the device to cope with it.

[0007] For example, PTL 1 discloses a cable configured such that two signal lines, a shield covering the periphery of the two signal lines, and two power lines are covered by a sheath layer. The sheath layer includes a magnetic powder mixed resin layer and a protective sheath layer covering the outer periphery of the magnetic powder mixed resin layer. It is possible to reliably suppress the intrusion of noise from the power line into the signal line. On the other hand, even if the noise from the signal line leaks from the shield layer, the magnetic powder mixed resin layer can reliably suppress the intrusion of noise into the power line 2.

[0008] Citation list

[0009] [Patent Document]

[0010] [PTL 1]

[0011] Japanese Patent 4032898 Summary of the invention

[0012] [Technical issues]

[0013] The configuration of PTL 1 as described above is directed to a cable configured such that a power line and a signal line are arranged in a common sheath layer, which is insufficient in measures against noise emission from the cable to the outside and noise intrusion from the outside into the cable.

[0014] Accordingly, an object of the present technology is to provide a cable and an antenna device having a coaxial cable, which can suppress the influence of noise that may be caused by the device and can suppress radiation noise from the cable.

[0015] [Solution to the problem]

[0016] The present technology provides a cable, comprising: a first shielding part, including at least one or more wires for transmitting signals or power, and arranged on the outside of the wires; a first layer, arranged to cover the outer periphery of the first shielding part, and including a resin that absorbs radio waves; a second shielding part, arranged on the outside of the first layer; a second layer, arranged to cover the outer periphery of the second shielding part, and including a resin that absorbs radio waves; and an insulating resin covering the outside of the second layer.

[0017] The present technology further provides an antenna device having a coaxial cable, wherein the cable as described above is connected to a balanced type antenna.

[0018] [Beneficial Effects of the Invention]

[0019] According to at least one embodiment, a first shielding part, a first layer, a second shielding part, and a second layer are provided in sequence, and noise caused by a large electromagnetic field in a near field can be suppressed thereby. The beneficial effects described herein are not necessarily restrictive, and any beneficial effects described in the present technology and beneficial effects different from these beneficial effects are applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [ Figure 1 ] Figure 1 It is a diagram used to explain the near field and far field.

[0021] [ Figure 2 ] Figure 2 is a graph depicting the amplitude of the electromagnetic field in the near field.

[0022] [ Figure 3 ] Figure 3 is a schematic diagram showing a method of measuring noise near a television receiver.

[0023] [ Figure 4 ] Figure 4 4A and 4B are diagrams for explaining noise in the high frequency band of the VHF band.

[0024] [ Figure 5 ] Figure 5 is a diagram for explaining noise in the UHF band.

[0025] [ Figure 6 ] Figure 6 is a diagram showing the noise of a television receiver relative to an indoor antenna.

[0026] [ Figure 7 ] Figure 7 7A and 7B are respectively a cross-sectional view and a front elevation view of an embodiment of the present technology.

[0027] [ Figure 8 ] Figure 8 It is a schematic diagram for explaining the noise suppression effect obtained by the embodiment of the present technology.

[0028] [ Fig. 9 ] Fig. 9 9A and 9B are schematic diagrams for explaining noise generation.

[0029] [ Fig.10 ] Fig.10 is a block diagram depicting the system configuration for sensitivity evaluation.

[0030] [ Fig.11 ] Fig.11 is a front elevation view depicting an example configuration regarding a receiving antenna.

[0031] [ Fig.12 ] Fig.12 : is a graph depicting the sensitivity evaluation results regarding the high frequency band of the VHF band.

[0032] [ Fig.13 ] Fig.13 is a graph depicting the sensitivity evaluation results of the UHF band.

[0033] [ Fig.14 ] Fig.14 This is a cross-sectional view of a USB 2.0 cable to which this technology is applicable.

[0034] [ Fig.15 ] Fig.15 This is a cross-sectional view of a USB 3.0 cable to which this technology is applicable.

[0035] [ Fig.16 ] Fig.16 This is a cross-sectional view of an Ethernet cable to which this technology is applicable.

[0036] [ Fig.17 ] Fig.17 It is a cross-sectional view of a modification of the present technology.

[0037] [ Fig.18 ] Fig.18 is a partial perspective view depicting the configuration of another example of the shield member related to the present technology.

[0038] [ Fig.19 ] Fig.19 is a perspective view for explaining a winding method of another example of the shield member related to the present technology.

[0039] [ Fig. 20 ] Fig. 20 It is a cross-sectional view for explaining a winding method of another example of the shield member related to the present technology.

[0040] [ Fig.21 ] Fig.21 It is a perspective view for explaining a winding method of still another example of the shield member related to the present technology.

[0041] [ Fig. 22 ] Fig. 22 It is a cross-sectional view for explaining a winding method of still another example of the shield member related to the present technology. DETAILED DESCRIPTION

[0042] The following will describe embodiments of the present technology with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred specific examples of the present technology and are subject to various technically advantageous limitations. However, unless otherwise specified in the following description to limit the present technology, the scope of the present technology should not be limited to these embodiments.

[0043] In the case where an electromagnetic shield is used near an antenna, the shielding effect changes depending on the wave impedance. Wave impedance is the ratio (E / H) of the electric field (E) to the magnetic field (H) at a specific location. Figure 1 It is a graph that depicts the change in wave impedance with respect to distance, and depicts the change in wave impedance of a micro dipole antenna and a micro loop antenna. Near the dipole antenna, the wave impedance is high because the electric field is strong. On the other hand, near the loop antenna, the wave impedance is low because the magnetic field is strong. If the distance exceeds λ (electromagnetic field wavelength) / (2π), the wave impedance of both antennas converges to a predetermined value (376.7Ω). Generally, the electromagnetic field up to this value λ / (2π) is called the near field, and the electromagnetic field farther than this value λ / (2π) is called the far field.

[0044] Figure 1 The distance r in a state normalized by λ / (2π) is depicted, and 1 on the abscissa axis corresponds to (r=λ / (2π); and this distance is the boundary between the near field and the far field. For example, in the case of 100 MHz, the boundary distance r=0.48 m, and (0.1) corresponds to (r=4.8 cm), and (10) corresponds to (r=4.8 m). Similarly, in the case of 200 MHz, (1: r=0.24 m), (0.1: r=2.4 cm), and (10: r=2.4 m) are all true. In addition, in the case of 500 MHz, (1: r=0.095 m), (0.1: r=0.95 cm), and (10: r=0.95 m) are all true.

[0045] Figure 2 The graph depicts the intensity of the electromagnetic field, the induced electromagnetic field and the radiated wave relative to the abscissa axis (λ / (2π)). Figure 2As can be seen from the figure, since the electromagnetic field is quite strong in the near field, shielding is required as a measure to combat noise. In order to suppress the influence of noise, it is necessary to reduce the influence of conducted noise transmitted to the cable and spatial noise entering the cable. In particular, since the impedance of the magnetic field component is very low, there is a problem that it is difficult to eliminate the noise of the magnetic field component.

[0046] The noise component generated from an electronic device (such as a commercially available television receiver 1) is measured. Figure 3 As shown, a dipole antenna 2 is installed near the back of the television receiver 1, and a reception signal of the dipole antenna 2 is supplied to a spectrum analyzer 4 via a cable 3. The noise component (spatial noise) received by the dipole antenna 2 can be analyzed by the spectrum analyzer 4.

[0047] Figure 4 A and 4B depict the Figure 3 The configuration depicted in FIG. 1 shows the level of the noise component of the VHF band high frequency band (179 to 228 MHz) obtained. In the case where the power supply of the television receiver 1 is turned off, as shown in FIG. Figure 4 As shown in FIG. 1A , the level of the noise component is quite low. On the other hand, when the power of the television receiver 1 is turned on, as shown in FIG. Figure 4 As depicted in B, the level of the noise signal becomes higher. Figure 5 Plotted is the frequency distribution of a noise signal in the UHF band (450 to 850 MHz) in the case where the power of the television receiver 1 is turned on. Also in the UHF band, the noise component is high as in the VHF band.

[0048] In particular, in an indoor antenna, such as a balanced antenna 7, as Figure 6 In the case of being connected to the television receiver 1 via the coaxial cable 8 shown in the figure, in order to minimize the influence of such noise components (spatial conduction noise) as described above, it is necessary to space the balanced antenna 7 from the television receiver 1. The coaxial cable 8 is connected to the television receiver 1 through an IEC connector or an F connector. For example, the present technology is applied to the coaxial cable 8. By the present technology, the noise entering the coaxial cable 8 and the noise generated from the coaxial cable 8 can be suppressed.

[0049] An embodiment of a cable according to the present technology that can suppress the magnetic field noise and electric field noise in the near field described above will be described below. Figure 7 7A and 7B are respectively a cross-sectional view and a front elevation view of a cable according to an embodiment of the present technology. Figure 7 The front elevation view of B depicts the internal structure of the cable in an easily understandable manner by peeling off the covering parts in order from the center to the peripheral side. This embodiment is an example in which the present technology is applied to a coaxial cable.

[0050] A wire (central conductor) 11 for signal transmission, for example, including annealed copper wire, is located at the center of the cable. An insulator 12, for example, including foamed polyurethane, polyethylene, foamed polyethylene, etc., is located outside the wire 11. Around the insulator 12, a first shielding part S1 having an electric field shielding function covering the insulator 12 is provided. The first shielding part S1, for example, includes an aluminum sheet 13 arranged on the outer surface of the insulator 12 and a braided wire 14 arranged on the outer surface of the aluminum sheet 13. The first shielding part S1 is not limited to having such a configuration as just described, and has a configuration including a braided wire formed by braiding annealed copper wire, another configuration including a braided wire and a metal sheet (aluminum, copper, iron, etc.) arranged on the inside or outside of the braided wire in the form of foil, a further configuration including a winding made by winding annealed copper wire, or a further configuration including a winding and a metal sheet (aluminum, copper, iron, etc.) arranged on the inside or outside of the winding in the form of foil. It should be noted that the annealed copper wire can be tinned.

[0051] The braided wire 14 of the first shield portion S1 is connected to a ground portion of a circuit inside the electronic device via a connector, etc. The first shield portion S1 is provided to suppress the influence of noise on the wire 11 or to suppress noise emission from the wire 11 to the outside.

[0052] A first layer F1 is arranged on the outer peripheral portion of the outer side of the braided wire 14 of the first shielding part S1, and the first layer F1 includes a resin that absorbs radio waves, such as a magnetic powder mixed resin. The first layer F1 has a magnetic shielding function. In other words, the first layer F1 has a function of being used as a measure against conducted noise. The magnetic powder mixed resin is a mixture of magnetic powder in a synthetic resin. An example of a synthetic resin is a styrene-based elastomer. Instead of a styrene-based elastomer, a synthetic resin such as an olefin-based elastomer or PCV can be used. An example of a magnetic powder is a nickel-zinc-based ferrite. In terms of a weight ratio to the resin, the ratio of iron powder or ferrite powder to the resin is equal to or higher than 70% and equal to or lower than 98%. And, as the magnetic powder, Ni-Cu-Zn-based ferrite, Mn-Zn-based ferrite, soft magnetic metal-based magnetic powder, copper-based magnetic powder, magnesium-based magnetic powder, lithium-based magnetic powder, zinc-based magnetic powder, iron-based (such as permalloy) magnetic powder, cobalt-based magnetic powder, and any other similar magnetic powder can be used.

[0053] The second shielding part S2 having an electric field shielding function is arranged in a manner covering the outer periphery of the first layer F1. The second shielding part S2 is, for example, an aluminum sheet. In addition to the aluminum sheet, only a braided wire or only a winding may be used. In addition, a combination of a braided wire or a winding and an aluminum metal sheet or the like may be used. The second shielding part S2 does not need to be grounded.

[0054] A second layer F2 is arranged on the outer peripheral portion of the outer side of the second shielding part S2, and the second layer F2 includes a resin that absorbs radio waves, such as a magnetic powder mixed resin. The second layer F2 with a magnetic shielding function is provided as a measure against spatial noise. The outer peripheral portion of the outer side of the second layer F2 is covered by a covering material 15. The covering material 15 can be formed using an insulating material, such as, for example, polyethylene, polypropylene, PVC (polyvinyl chloride) or an elastomer.

[0055] Generally, complex magnetic permeability is expressed by a real part of an inductance component and an imaginary part corresponding to a resistance component (loss component), as shown by the following expression.

[0056] [Mathematics 1]

[0057]

[0058] When the first layer F1 and the second layer F2 are compared with each other, the first layer F1 has a function of converting noise into heat through the high-frequency resistance indicated by the imaginary part, and the second layer F2 has a function of magnetic shielding that suppresses the influence of the inductance component indicated by the real part on the magnetic field. That is, the high-frequency impedance of the ferrite of the first layer F1 on the inside prevents noise from entering the outer covering of the braided wire 14 of the first shielding part S1. In addition, the influence of noise (spatial conduction noise) from the outside can be prevented by the magnetic shielding formed by the second layer F2. Even if the thickness of the first layer F1 is not made large, since the effect of the ferrite depends on its volume, the high-frequency resistance of the cable becomes higher, and the noise of the braided wire 14 of the first shielding part S1 that may be caused to the outer covering can be suppressed.

[0059] refer to Figure 8 Describe the influence of the noise generation source (transmitting side) on the equipment (protected side) such as the electronic circuit and the noise suppression function obtained by the present technology. As the types of noise interference, there are conductor conduction for conducting the noise to the equipment side via the conductor, space conduction for conducting the noise to the equipment side via the space, conductor-space conduction for conducting the noise to the equipment side via the conductor and then via the space, and space-conductor conduction for conducting the noise to the equipment side via the space and then the conductor. In the case where the device is an antenna, the device needs to be separated from the TV receiver as the noise generation source by a necessary distance (preferably 2.4m or more in the case of 200MHz). In the case where the device is not an antenna, the device needs to be shielded.

[0060] refer to Figure 8, the solid arrow marks represent the electric field component of the noise, and the dotted arrow marks represent the magnetic field component of the noise. The second shielding portion S2 can reflect the electric field component of the noise, and the second layer F2 can suppress the magnetic field component of the noise. Specifically, the influence of the noise caused by the spatial conduction of the near field can be alleviated by the second shielding portion S2 and the second layer F2. In addition, the noise (noise caused by conductor conduction and noise caused by conductor-spatial conduction) flowing into the first shielding portion S1 connected to the ground of the device can be suppressed by the first layer F1.

[0061] refer to Fig. 9 A and 9B describe conventional measures against noise generating sources. Fig. 9 In the case where the circuit board 22 shown in A is housed in the shield case 21, noise caused by conductor conduction through the wire 23 entering and exiting the shield case 21 is generated, and noise caused by spatial conduction is generated through the wire 23 serving as an antenna. In this way, even if an effort is made to remove the noise caused by spatial conduction by the shield case 21, noise is still generated through the wire 23 entering and exiting the shield case 21.

[0062] As a measure against this, the following configuration has been used, where Fig. 9 B, a shielded cable 24 (indicated by a dotted line) covering the wire 23 is provided, and the shielded cable 24 is connected to the circuit ground of the circuit board 22, and is connected to the shell shield ground of the shield shell 21. In the case where the circuit ground is in a sufficiently stable state, it is only necessary to connect the shielded cable 24 to the circuit ground. In the case where the shielded cable 24 is only connected to the shell shield ground, it is necessary to separately provide a wiring for connecting the shell and the circuit ground to each other as a signal wiring. However, even with the countermeasure just described, the noise suppression effect is still insufficient.

[0063] By Fig.10 The system configured in the manner shown is used to evaluate the noise suppression performance of the present technology. A test signal (for example, DVB-T2 mode) is generated by a signal generator 31, the signal level of the test signal is changed by an attenuator 32, and then the test signal is transmitted by a transmitting antenna 33. A receiving antenna 34 having a configuration of a balanced antenna is set at a position spaced a predetermined distance from the transmitting antenna 33, and the received signal of the receiving antenna 34 is provided to a television receiver 36 via a coaxial cable 35 and an F connector (or an IECIEC (International Electrotechnical Commission) connector) of, for example, 1.3 meters in length. As the length of the coaxial cable 35, a length equal to or greater than 1 m is preferably used to ensure the amount necessary for noise suppression of the magnetic powder contained in the first layer F1 and the second layer F2, respectively.

[0064] The transmission signal level that can be received in the case where the transmission signal level is gradually reduced by the attenuator 32 is measured. As the measurement signal, for example, a sound signal is used. A microphone 37 that detects the output sound of the television receiver 36 is used, and the output signal of the microphone 37 is amplified by an amplifier 38 and monitored by a sound monitor (e.g., a speaker) 39 outside a dark room (indicated by a surrounding dotted line) 40. Instead of monitoring the sound, an imaging device may be used to monitor the image instead of the microphone 37.

[0065] Fig.11 . As a balanced transmission path, two wirings 52 and 53 are arranged in parallel with each other on an insulating plate 51. One end of the wiring 52 is connected to the center conductor (core wire) of the coaxial cable 35, and one end of the wiring 53 is connected to the outer conductor (braided wire) of the coaxial cable 35. The coaxial cable 35 is connected to the tuner of the television receiver 36 via, for example, an F-type connector 41.

[0066] Antenna elements 60 and 70 are provided on both sides of the balanced transmission path. Antenna elements 60 and 70 have similar configurations to each other. Antenna element 60 is connected to the other end of wiring 52, and antenna element 70 is connected to the other end of wiring 53. Antenna element 60 is configured as a triangular antenna element by connecting the ends of linear elements 61 and 62, the ends of linear elements 61 and 63, and the ends of linear elements 62 and 63 to each other, respectively.

[0067] In addition, the antenna element 70 is similarly configured as a triangular antenna element by connecting the ends of the linear elements 71 and 72, the ends of the linear elements 71 and 73, and the ends of the linear elements 72 and 73 to each other, respectively. The vertex portion formed by the ends of the linear elements 72 and 73 is connected to the other end of the wiring 53 of the balanced transmission path.

[0068] In addition, a linear element 74 is provided, which is connected to the linear element 71 of the triangular antenna element and extends (or folds back) toward one end of the wiring 53 of the balanced transmission path. The extended end of the linear element 74 is fixed to the insulating plate 51. However, the linear element 74 is not connected to the wiring 53. There is impedance matching between the balanced transmission path and the linear element 74.

[0069] The lengths (L1, L2, L3, and L4) of the linear elements 61, 62, 63, and 64 and the lengths of the linear elements 71, 72, 73, and 74 are respectively set equal to each other. As described above, the lengths are set according to the reception frequency.

[0070] The linear elements 61 to 64 and 71 to 74 are formed using metal wires including a material having conductivity such as copper, silver, iron, or aluminum, and can flexibly change the shape of the antenna elements 60 and 70. In addition, in order to maintain strength in a case where the material is repeatedly bent or curved to change the shape, the material may be configured as a binding wire in which two or more metal wires are bound. In addition, each of the insulating plates 51, 65, and 75 is a printed circuit board of glass epoxy resin or ceramic, an FPC (flexible printed circuit), a glass plate, or a plastic plate of molded resin, etc. In addition, the insulating plates 51, 65, and 75 may be completely covered as a whole with a housing of resin or the like.

[0071] The antenna element 70 constitutes a dipole antenna together with the antenna element 60. In addition, the feed point 100 to the antenna device is the other end side of the balanced transmission path (wiring 52 and 53), and by appropriately setting the length of the balanced transmission path, the unbalanced transmission line (coaxial cable 35) can be connected to the balanced load (antenna device) without using a balun (balanced-unbalanced converter). By inserting a balanced transmission path, the phase can be adjusted and a wider bandwidth can be achieved.

[0072] With the above-mentioned antenna device, a wider bandwidth can be achieved by setting the length of each linear element of the antenna elements 60 and 70 to a value corresponding to the received frequency. Specifically, in order to receive the high frequency band (200Mhz band) of the VHF band, the length of (L3+L1+L4) or (L2+L4) is set to approximately (1 / 4) of the wavelength (λ1) of the band, for example, to approximately 38cm. In addition, in order to receive the frequency band (470Hz to 800MHz) of terrestrial digital television in the UHF band, the length of L3 or L2 is set to approximately (1 / 4) of the wavelength (λ2) of the band, for example, to approximately 16cm. The lengths L1 to L4 are values ​​including the wavelength shortening rate.

[0073] By Fig.10 The results of the receive sensitivity evaluation performed on this system are shown in Fig.12 and 13 Shown in. Fig.12 is a graph depicting the reception sensitivity evaluation of the VHF band high band (179 to 228 MHz), and Fig.13 Graphs depicting reception sensitivity evaluations of the UHF band (450 to 850 MHz) In these graphs, the abscissa axis represents frequency, the ordinate axis represents sensitivity, and smaller values ​​on the ordinate axis represent better sensitivity.

[0074] Fig.12 and 13The figure in represents each sensitivity in the case where the type of the coaxial cable 35 is changed. Specifically, the sensitivity of the coaxial cable 35 is described with respect to the ordinary coaxial cable, the coaxial cable of the S+F configuration, the coaxial cable of the S+F+S configuration, and the coaxial cable of the S1+F1+S2+F2 configuration (configuration of the present technology). It should be noted that S, S1, and S2 represent shielding parts, and F, F1, and F2 represent resin layers in which magnetic powder of ferrite or the like is mixed, and they are described in order from the center of the cable to the outside.

[0075] from Fig.12 As can be recognized from the graph, the coaxial cable to which the present technology is applied has the highest sensitivity characteristic. The coaxial cable with the second highest sensitivity characteristic is S+F; the coaxial cable with the third highest sensitivity characteristic is S+F+S; and the ordinary coaxial cable has the lowest sensitivity characteristic. In the frequency band of the VHF band high frequency band, since the influence of the magnetic field is large, the configuration with a higher magnetic field shielding effect indicates better results.

[0076] from Fig.13 As can be recognized from the graph, the coaxial cable to which the present technology is applied has the highest sensitivity characteristic. The coaxial cable with the second highest sensitivity characteristic is S+F+S; the coaxial cable with the third highest sensitivity characteristic is S+F; and the ordinary coaxial cable has the lowest sensitivity characteristic. In the frequency band of the UHF band, since the influence of the electric field is large, the configuration with a higher electric field shielding effect indicates better results.

[0077] The foregoing description is directed to an embodiment in which the present technology is applied to a coaxial cable. The present technology can also be applied to cables other than coaxial cables. A cable to which the present invention can be applied will be described.

[0078] Fig.14 : is a cross-sectional view of a USB 2.0 cable. The USB cable includes five wirings, including a set of signal cables 81a (D-) and 81b (D+) for differential transmission, power cables 82a and 82b, and a drain wire 83 as a ground wire. Each of the cables 81a, 81b, 82a, and 82b is formed by covering the outer periphery of a core wire with an insulating coating.

[0079] The core wire can be formed using copper and can be formed using any one of a configuration of a single wiring including a single conductor and another twisted wire configuration in which thin conductors are twisted into a single conductor. The signal cables 81a and 81b form a twisted pair cable. The signal cables 81a and 81b and the power cables 82a and 82b are covered by an aluminum foil shield 84 and a copper wire mesh shield 85. The drain wire 83 and the aluminum foil shield 84 are electrically connected to each other.

[0080] In the case of applying the present technology to the USB 2.0 cable as described above, the aluminum foil shield 84 and the copper wire mesh shield 85 are applied as the first shielding part S1. In addition, the first layer F1, the second shielding part S2, and the second layer F2 are arranged on the outer peripheral side of the first shielding part S1. A coating 86 is provided on the outermost periphery. The USB 2.0 cable to which the present technology is applied can suppress noise.

[0081] Fig.15 is a cross-sectional view of a USB 3.0 cable. Like a USB 2.0 cable, a USB 3.0 cable includes four wirings, including a set of signal cables 91a and 91b for differential transmission and power cables 92a and 92b. Signal cables 91a and 91b are called UTP (unshielded twisted pair). The USB 3.0 cable also includes signal cables 93a and 93b and drain wire 93c of USB 3.0, as well as other signal wires 94a and 94b and drain wire 94c of USB 3.0. Signal cables 93a and 93b are called SDP (shielded differential pair). Filling material 95 is used as an option. The wiring and filling material are covered with a copper wire mesh shield 96.

[0082] In the case of applying the present technology to the USB 3.0 cable as described above, the copper wire mesh shield 96 is applied as the first shielding part S1. In addition, the first layer F1, the second shielding part S2, and the second layer F2 are sequentially arranged on the outer peripheral side of the first shielding part S1. A coating 97 is provided on the outermost periphery. The USB 3.0 cable to which the present technology is applied can suppress noise.

[0083] Fig.16 : is a cross-sectional view of an Ethernet cable (LAN cable). The four pairs of signal wires 101a, 101b, 101c and 101d of the twisted pair cable configuration are covered by a shield. The shield includes a shield portion 102 of aluminum / PET and a braided wire 103 that are layered from the inside.

[0084] In the case of applying the present technology to the Ethernet cable (LAN cable) as described above, the shielding part 102 of aluminum / PET and the braided wire 103 are applied as the first shielding part S1. In addition, the first layer F1, the second shielding part S2, and the second layer F2 are sequentially arranged on the outer peripheral side of the first shielding part S1. The coating 104 is provided on the outermost periphery. The Ethernet cable (LAN cable) to which the present technology is applied can suppress noise.

[0085] Fig.17 1 is a cross-sectional view of a modification of the present technology applied to a cable including two wirings 110a and 110b. Each of the wirings 110a and 110b is a power supply cable including two wirings of a signal transmission line or a hot line and a ground line. The wirings 110a and 110b have a structure similar to Figure 7 Shielding configuration of the illustrated embodiment. Specifically, an insulator 12 is provided on the outside of the wirings 110a and 110b, including, for example, foamed polyurethane, polyethylene, foamed polyethylene, etc. Around the insulator 12, a first shielding portion S1 having an electric field shielding function and covering the insulator 12 is provided. The first shielding portion S1 includes, for example, an aluminum sheet 13 arranged on the outer surface of the insulator 12 and a braided wire 14 arranged on the outer surface of the aluminum sheet 13. The first shielding portion S1 is not limited to having such a configuration as just described, but has a configuration including a braided wire formed by braiding annealed copper wire, another configuration including a braided wire and a metal sheet (aluminum, copper, iron, etc.) arranged in a foil shape on the inside or outside of the braided wire, a further configuration including a winding manufactured by winding annealed copper wire, or a further configuration including a winding and a metal sheet (aluminum, copper, iron, etc.) arranged in a foil shape on the inside or outside of the winding.

[0086] A first layer F1 is arranged on the outer peripheral portion of the outer side of the braided wire 14 of the first shielding part S1, and the first layer F1 includes a resin that absorbs radio waves, for example, a magnetic powder mixed resin. The first layer F1 has a function of magnetic shielding. In other words, the first layer F1 has a function of being used as a measure against conducted noise. The magnetic powder mixed resin is a mixture of magnetic powder in a synthetic resin. An example of a synthetic resin is a styrene-based elastomer. Instead of a styrene-based elastomer, a synthetic resin such as an olefin-based elastomer or PCV can be used. An example of a magnetic powder is a nickel-zinc-based ferrite. The ratio of iron powder or ferrite powder to resin is equal to or higher than 70% and equal to or lower than 98% in terms of weight ratio to the resin. As the magnetic powder, Ni-Cu-Zn-based ferrite, Mn-Zn-based ferrite, soft magnetic metal-based magnetic powder, copper-based magnetic powder, magnesium-based magnetic powder, lithium-based magnetic powder, zinc-based magnetic powder, iron-based (e.g., Permalloy) magnetic powder, cobalt-based magnetic powder, and any other similar magnetic powder can also be used.

[0087] The second shielding part S2 having an electric field shielding function is arranged in a manner covering the outer periphery of the first layer F1. The second shielding part S2 is, for example, an aluminum sheet. In addition to the aluminum sheet, only a braided wire or only a winding may be used. In addition, a combination of a braided wire or a winding and an aluminum metal sheet or the like may be used. The second shielding part S2 does not need to be grounded.

[0088] A second layer F2 is arranged on the outer peripheral portion of the outer side of the second shielding part S2, and the second layer F2 is made of a resin that absorbs radio waves, for example, a magnetic powder mixed resin. The second layer F2 having a magnetic shielding function is provided as a measure against spatial noise. The outer peripheral portion of the outer side of the second layer F2 is covered with a covering material 15. The covering material 15 can be formed using an insulating material such as polyethylene, polypropylene, PVC (polyvinyl chloride) or an elastomer.

[0089] Modifications of the present technology will be described below. Fig.18 As shown, the member provided on the braided wire 14 of the first shielding part S1 is configured as a shielding member SP in the form of a sheet or a tape. For example, a double-sided tape 16 is provided on the innermost peripheral side, and a magnetic sheet F11 constituting the first layer F1 is stacked on the double-sided tape 16. A conductive layer S12 constituting the second layer S2 is stacked on the magnetic sheet F11. The magnetic sheet F12 constituting the second layer F2 is stacked on the conductive layer S12. It should be noted that the double-sided tape 16 may not be provided.

[0090] The conductive layer S12 includes a metal foil of aluminum, copper, etc., and a magnetic material such as iron powder, ferrite powder or carbon powder is vapor deposited or coated on both surfaces of the metal foil. As an example, the thickness of the magnetic sheets F11 and F12 is 0.05 mm, and the thickness of the conductive layer S12 is 0.03 mm.

[0091] The shield member SP as described above is tightly wound around the first shield portion S1 (for example, see Figure 7 A) on the outer surface of the braided wire 14, such as Fig.19 Although, Fig.19 In order to facilitate understanding, a gap is provided between the ends of the shield member SP, but the shield member SP is wound around the braided wire 14 so that the ends thereof overlap each other, as shown in FIG. Fig. 20 The outer peripheral surface of the magnetic sheet F12 is covered with a covering material (not depicted). The covering material is, for example, an insulating material such as polyethylene, polypropylene, PVC (polyvinyl chloride) or an elastomer.

[0092] like Fig.21 As shown, the sheet-shaped shielding member SP' can be tightly wound around the braided wire 14, as shown in FIG. Fig.21 As shown. Fig.21 and 22 As shown, the ends of the sheet-shaped shielding member SP' in the cable extension direction overlap each other. As in the shielding member SP, in the shielding member SP', the magnetic sheet F11 and the magnetic sheet F12 are formed by adhering magnetic materials to both surfaces of the conductive layer S12 by vapor deposition or coating. The outer peripheral surface of the magnetic sheet F12 is covered with a covering material (not shown). The covering material is, for example, an insulating material such as polyethylene, polypropylene, PVC (polyvinyl chloride) or an elastomer.

[0093] The magnetic sheet F11 of the shielding member SP or the shielding member SP' has a function of serving as a measure against conductive noise, as the first layer F1 including the magnetic powder mixed resin described above does, and the magnetic sheet F12 is provided as a measure against spatial noise, as the second layer F2. The conductive layer S12 has a function of the second shielding portion S2 (electric field shielding function).

[0094] Compared with the first layer F1 and the second layer F2 in which magnetic powder is mixed in a synthetic resin, the magnetic permeability of the magnetic sheet F11 and the magnetic sheet F12 in which the magnetic material is vapor deposited or coated can be improved, and the layer thickness can be reduced. Therefore, the cable can be made thinner and lighter. A small-sized and light-weight cable is preferred as a cable to be used, for example, a cable used in a vehicle.

[0095] Although the embodiments of the present technology have been specifically described, the present technology is not limited to the above embodiments, and various modifications can be made based on the technical ideas of the present technology. For example, the configurations, methods, steps, shapes, materials, values, etc. specified in the embodiments described above are only final examples, and configurations, methods, steps, shapes, materials, values, etc. different from them can be used as occasion requirements. For example, the present technology can be applied not only to the above cables, but also to HDMI (registered trademark) cables, IEEE (Institute of Electrical and Electronics Engineers) 1394 cables, etc.

[0096] 11: Line

[0097] 12: Insulator

[0098] 13: Aluminum sheet

[0099] 14: Braided wire

[0100] S1: First shielding part

[0101] F1: First floor

[0102] S2: Second shielding part

[0103] F2: Second floor

[0104] SP, SP': shielding member

Claims

1. A cable, comprising: One or more wires used to transmit signals or power; a first shielding portion, the first shielding portion being disposed outside the line; a first layer of magnetic material, the first layer being arranged to cover an outer periphery of the first shielding portion and including a member for absorbing radio waves; a second shielding portion, the second shielding portion being disposed outside the first layer; a second layer of magnetic material, the second layer being arranged to cover an outer periphery of the second shielding portion and including a member for absorbing radio waves; as well as an insulating resin covering an outer side of the second layer, Wherein, a tape or sheet formed by vapor depositing or coating the first layer of the magnetic material and the second layer of the magnetic material on opposite surfaces of the second shielding portion is wrapped around the outside of the first shielding portion.

2. The cable according to claim 1, wherein the first shielding portion comprises a braided wire manufactured by braiding annealed copper wires, a winding manufactured by winding annealed copper wires, or a metal sheet formed at an upper portion or a lower portion of the braided wire or the winding.

3. The cable according to claim 2, wherein the metal sheet comprises a metal, and the metal comprises aluminum, copper or iron.

4. The cable of claim 1, wherein the wires comprise twisted pair cables for transmitting one or more sets of signals.

5. The cable according to claim 1, wherein the first layer has high frequency resistance and has a function of converting noise into heat. The cable according to claim 1 , wherein the second layer has a magnetic shielding function for preventing the influence of a magnetic field.

7. An antenna device having a coaxial cable, wherein the cable according to claim 1 is connected to a balanced type antenna.

8. The antenna device with a coaxial cable according to claim 7, wherein a length of the coaxial cable connected to the balanced type antenna is equal to or longer than 1 m.

9. The antenna device with a coaxial cable according to claim 7, wherein a connector of the coaxial cable connected to the balanced type antenna is an IEC connector or an F connector.

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