KR20210123976A - Coaxial cable - Google Patents

Abstract

Provided is a coaxial cable having a good outer appearance and having excellent processibility. The present invention comprises: a central conductor (11); an insulator (12) installed on the outer circumference of the central conductor (11); outer conductors (13, 14) installed on the outer circumference of the insulator (12); and outer covers (15, 16) enveloping the outer conductors (13, 14). The outer conductors (13, 14) consist of a horizontal winding shield (13) installed by winding a metallic thin wire horizontally around the outer circumference of the insulator (12); and a metallic resin tape (14) wound around the horizontal winding shield (13) with a metallic layer side overlapped as an inner side. The outer covers (15, 16) consist of a resin tape (15) wound around a metallic resin tape (14); and an extrusion sheath enveloping the resin tape (15). T2/T1 is equal to or greater than 1/4 and equal to or smaller than 4/5 where the thickness of the resin tape (15) is T2 and the thickness of the metallic resin tape (14) is T1.

Description

Coaxial Cable {COAXIAL CABLE}

The present invention relates to a coaxial cable, and more particularly, to a coaxial cable that is used for in-device antenna wiring or semiconductor devices conforming to the 5th generation communication standard (5G), has a good appearance, and has excellent workability.

Coaxial cables are used for transmission of high-frequency signals because they have excellent shielding characteristics against noise and the like. In such a coaxial cable, when an external force acts on the cable, the insulator deforms, the impedance fluctuates, and reflection attenuation occurs, and there exists a problem that transmission efficiency falls. Moreover, while thinning is requested|required for the coaxial cable used for in-device antenna wiring and a semiconductor device, favorable bending characteristic is calculated|required.

In response to such a request, Patent Document 1 proposes a coaxial cable that satisfies shield properties, flexibility, narrow configuration, flex resistance, and economy, and improves terminal workability. This coaxial cable has a structure in which a center conductor, an insulator, an outer conductor having a cross-winding shield structure, and a sheath are sequentially laminated coaxially. When the sheath is PFA, the insulator is formed by fluorinated PFA, and when the sheath is FEP or FTFE, the insulator is formed by any one of fluorinated FEP, PFA, and fluorinated PFA. In addition, a metal-deposited or plated tape layer is installed between the insulator and the external conductor, the transverse winding angle of the transverse winding line of the external conductor is set to 70˚ to 85˚, or the center conductor is a multi-wire or single-wire conductor It is suggested that it is preferable to

Japanese Patent Application Laid-Open No. 2007-188782

In recent years, coaxial cables have been used for transmission of high-frequency signals in electronic devices, such as PCs, smartphones, and tablet terminals, which are being miniaturized. is being demanded In particular, a coaxial cable used for in-device antenna wiring or semiconductor devices conforming to the 5th generation communication standard (5G) is required to have a thin diameter and good transmission characteristics.

The coaxial cable of Patent Document 1 is provided with an outer conductor made of a transversely wound shield in which a thin wire is transversely wound, and is thinner than a conventional outer conductor made of a braided shield in which a thin wire is braided. It is advantageous. However, in the case of a transverse winding shield, it is easy to generate|occur|produce between the thin wire wound transversely at the time of wiring etc., and there exists a possibility that the shielding effect may fall. In order to solve this problem, a metal resin tape is overlapped with a predetermined wrap on the transverse winding shield, and a decrease in the shielding effect is suppressed.

When the metal resin tape is rolled over, there is air in the step caused by the thickness of the metal resin tape, and the air then expands with the heat when the extrusion sheath is extrusion-molded, causing irregularities and deterioration of the appearance. There was a problem. For this reason, extrusion molding was carried out while suctioning with a vacuum pump so that as little air remained as possible, but it was not sufficiently solved. These appearance irregularities change the outer diameter in the longitudinal direction of the coaxial cable, and when the terminal is connected to the connector, when the same terminal processing conditions are used, the processing yield deteriorates. Therefore, the terminal processing conditions must be changed every time. .

The present invention has been made in order to solve the above problems, and the object thereof is to provide a coaxial cable with good appearance and excellent workability, which is used for in-device antenna wiring or semiconductor devices compliant with the 5th generation communication standard (5G). is in doing

A coaxial cable according to the present invention is a coaxial cable comprising a central conductor, an insulator provided on the outer periphery of the central conductor, an outer conductor provided on the outer periphery of the insulator, and a shell covering the outer conductor, The outer conductor is composed of a transverse winding shield provided by horizontally winding a thin metal wire around the outer periphery of the insulator, and a metal resin tape wound over the transverse winding shield with a metal layer side inside, wherein the outer conductor includes the metal resin tape It is composed of a resin tape wound on top and an extruded sheath covering the resin tape, and when the thickness of the resin tape is T2 and the thickness of the metal resin tape is T1, T2/T1 is 1/4 or more 4/ It is characterized in that it is within the range of 5 or less.

According to this invention, since the thickness (T2) of the resin tape and the thickness (T1) of the metal resin tape are in the above relationship, the step difference can be made small (about 1/4 to 4/5) compared to the case of only the metal resin tape, , it is possible to suppress the appearance irregularities caused by the air present in the level difference. As a result, changes in the outer diameter in the longitudinal direction can be suppressed, and terminal processing can be performed under the same conditions when connecting the terminal to the connector. In addition, since the outer conductor has a transverse winding shield, it is possible to realize narrower thickness compared to the braided shield. Further, since the metal resin tape is provided on the transverse winding shield, it is possible to suppress a decrease in the shielding effect even if a gap occurs in the transverse winding shield. Such a coaxial cable can realize thinness that can realize in-device wiring in a narrow space, and is particularly suitable for in-device antenna wiring or semiconductor devices conforming to the 5th generation communication standard (5G).

The coaxial cable which concerns on this invention WHEREIN: The thickness of the said metal resin tape is 8 micrometers or more and 18 micrometers or less, and the thickness of the said resin tape is 4 micrometers or more and 9 micrometers or less. According to this invention, since the thickness of a metal resin tape and the thickness of a resin tape are within the said range, compared with the case where only the metal resin tape is used, the level|step difference can be made small (about 9 micrometers or less).

In the coaxial cable according to the present invention, the metal resin tape and the resin tape are wound overlappingly in the range of 1/4 wrap to 1/2 wrap. According to this invention, the level|step difference at the time of overlapping winding in such a range can be made small.

In the coaxial cable according to the present invention, an adhesive layer is provided on one side of the resin tape, and the adhesive layer is wound inside. According to this invention, since the metal resin tape is fixed so as not to be shifted by the adhesive layer of the resin tape, there is no shift in the transverse winding shield even if stress is applied during wiring of the coaxial cable. As a result, a decrease in the shielding effect can be suppressed.

ADVANTAGE OF THE INVENTION According to this invention, the coaxial cable which is used for in-device antenna wiring and a semiconductor device conforming to the 5th generation communication standard (5G), has a good external appearance, and is excellent in processability can be provided. In particular, since the appearance unevenness is suppressed, the change in the outer diameter in the longitudinal direction can be suppressed, and terminal processing can be performed under the same conditions when the terminal is connected to the connector. In addition, as compared with the braided shield, it is possible to achieve a narrower thickness, and even if a gap occurs in the transverse winding shield, it is possible to suppress a decrease in the shielding effect.

1 is a perspective configuration diagram showing an example of a coaxial cable according to the present invention.
2(A) is an example in which the insulator has a solid structure, and FIG. 2(B) is an example in which the insulator has a hollow structure.

EMBODIMENT OF THE INVENTION Embodiment of the coaxial cable which concerns on this invention is described, referring drawings. In addition, this invention includes invention of the technical idea similar to the embodiment described below and the form described in drawing, The technical scope of this invention is not limited only to description of embodiment and description of drawing.

[coax]

As shown in FIG. 1 , the coaxial cable 10 according to the present invention includes a central conductor 11 , an insulator 12 provided on the outer periphery of the central conductor 11 , and an outer periphery of the insulator 12 . It is a coaxial cable provided with the outer conductors 13 and 14 used as an external conductor, and the outer conductors 13 and 14, and the outer sheath 15, 16 which covers it. And, as a feature thereof, the external conductors 13 and 14 include a transverse winding shield 13 provided by winding a thin metal wire horizontally around the outer periphery of the insulator 12, and on the transverse winding shield 13, with the metal layer side inside, It is composed of a metal resin tape 14 wound on top of each other, and the outer shells 15 and 16 are composed of a resin tape 15 wound on the metal resin tape 14 and an extruded sheath 16 covering the resin tape 15 . When the thickness of the resin tape 15 is T2 and the thickness of the metallic resin tape 14 is T1, T2/T1 is 1/4 (=0.25) or more and 4/5 (=0.8) or less. It is characterized in that it is within the range.

Since this coaxial cable 10 is (1) the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 have a relationship of "T2/T1 = 1/4 to 4/5", , the step difference can be made small (about 1/4 to 4/5) compared to the case of only the metal resin tape 14, and the appearance irregularities due to the air present in the step can be suppressed. As a result, changes in the outer diameter in the longitudinal direction can be suppressed, and terminal processing can be performed under the same conditions when connecting the terminal to the connector. (2) Furthermore, since the outer conductor has the transverse winding shield 13, it is possible to realize narrower thickness compared to the braided shield. (3) Furthermore, since the metal resin tape 14 is provided on the transverse winding shield 13, even if a gap occurs in the transverse winding shield 13, a decrease in the shielding effect can be suppressed. Such a coaxial cable 10 can realize the thinness that can realize in-device wiring in a narrow space, and is particularly suitable for in-device antenna wiring or semiconductor devices conforming to the 5th generation communication standard (5G). do.

Hereinafter, each component will be described in detail.

As shown in FIG. 1 , the coaxial cable 10 includes a central conductor 11 , an insulator 12 provided on the outer periphery of the central conductor 11 , and an outer conductor 13 provided on the outer periphery of the insulator 12 . , 14) and outer conductors 13 and 14 covering the outer conductors 13 and 14, respectively.

(center conductor)

The central conductor 11 is comprised from one strand extended in the longitudinal direction of the coaxial cable 10, or is comprised by twisting a plurality of strands. The type of the wire is not particularly limited as long as it is a positively conductive metal, but a metal conductor of high conductivity such as a copper wire, a copper alloy wire, an aluminum wire, an aluminum alloy wire, and a copper-aluminum composite wire, or a plating layer on these surfaces What was formed is mentioned as a preferable thing. From a viewpoint for high frequency use, a copper wire and a copper alloy wire are especially preferable. As a plating layer, a solder plating layer, a tin plating layer, a gold plating layer, a silver plating layer, a nickel plating layer, etc. are preferable. The cross-sectional shape of the strand is also not particularly limited, and the cross-sectional shape may be a circular or substantially circular wire, or may be a square shape.

The cross-sectional shape of the central conductor 11 is also not specifically limited. A circular shape (including an oval shape) may be sufficient, a rectangle, etc. may be sufficient, However, It is preferable that it is circular. The outer diameter of the central conductor 11 is preferably as large as possible so that the electrical resistance (AC resistance, conductor resistance) becomes small. can be within the range of An insulating film (not shown) may be provided on the surface of the central conductor 11 as needed. Although the kind and thickness of an insulating film are not specifically limited, For example, it is preferable that it decomposes|disassembles favorably at the time of soldering, and a thermosetting polyurethane film etc. are mentioned as a preferable thing.

(insulator)

The insulator 12 is an insulating layer of low dielectric constant provided continuously in the longitudinal direction on the outer periphery of the central conductor 11 as shown in FIGS. 1 and 2 . The material of the insulator 12 is not particularly limited and is arbitrarily selected depending on the required impedance characteristics. For example, PFA (ε2.1), ETFE (ε2.5), FEP (ε2.1), etc. have a dielectric constant of 2.0 A fluorine-based resin having a low dielectric constant of ~2.5 is preferable, and among these, a PFA resin is preferable. Moreover, you may make the material of the insulator 12 contain a coloring agent. The thickness of the insulator 12 is also not particularly limited, and although it is arbitrarily selected according to the required impedance characteristic, it is preferable to set it within the range of about 0.15-1.5 mm, for example. Although the formation method of the insulator 12 is not specifically limited, A solid structure, a hollow structure, and a foam structure can all be formed easily by extrusion.

The insulator 12 may have a solid structure shown in Fig. 2(A), a hollow structure shown in Fig. 2(B), or a foamed structure (not shown). Further, the hollow structure has a void portion 12' inside the structure, and for example, the void portion 12' is surrounded by an inner annular portion 12a, an outer annular portion 12b, and a connecting portion 12c. can be said to be a cross-sectional shape, etc. In the case of a hollow structure or a foam structure, the material density of the insulator 12 is reduced, and there is an additional effect of making the insulator 12 flexible.

(outer conductor)

The outer conductors 13 and 14 are provided on the outer periphery of the insulator 12 as shown in FIG. 1 . The outer conductors 13 and 14 are formed by a transverse winding shield 13 provided by winding a thin metal wire horizontally around the outer periphery of the insulator 12, and a metal resin tape wound on the transverse winding shield 13 with the metal layer side inside and overlapped ( 14) consists of The outer conductor having such a double structure has a large conductor cross-sectional area and can reduce insertion loss. In addition, since the outer conductor has the transverse winding shield 13, it is possible to realize narrowing compared to the braided shield. In addition, since the metal resin tape 14 is provided on the transverse winding shield 13 in the form of electrical connection (the thin wire and the metal layer are in direct contact), stress is applied to the transverse winding shield 13 and the thin wire It is possible to suppress a decrease in the shielding effect even when a gap occurs between them.

(Horizontal Winding Shield)

The transverse winding shield 13 is formed by transversely winding a thin metal wire on the insulator 12 as shown in FIG. 1 . Although the thin metal wire wound horizontally may be the single layer shown in FIG. 1 or the lamination|stacking which is not shown in figure, is not specifically limited, A single layer is preferable. The transverse winding of the thin metal wires makes it possible to reduce the thickness of the transverse winding shield 13 within a range that produces the same effect (sealing effect, etc.) compared to a braided structure in which the thin wires intersect to form a twisted eye, It is advantageous from the viewpoint of the narrowing of the coaxial cable 10 .

The thin metal wire is not particularly limited as long as it is a conductive metal wire that can be provided on the outer periphery of the insulator 12 as the transverse winding shield 13 constituting the coaxial cable 10 . For example, various metal fine wires typified by a tin-plated copper wire or the like can be preferably used. The outer diameter of the fine metal wire is not particularly limited, and it is determined in relation to the outer diameter of the insulator 12 , and for example, it is in the range of about 0.04 to 0.1 mm. The number of fine metal wires is also arbitrarily selected according to the outer diameter of the insulator 12 or the predetermined outer diameter of the coaxial cable 10 . Although the horizontal winding pitch at the time of transversely winding a metal fine wire is also not specifically limited, Usually, it is preferable that it is about 0.5-11 mm.

(Metal Resin Tape)

The metal resin tape 14 is installed by transverse winding (spiral winding) on the transverse winding shield 13, as shown in FIG. The metal resin tape 14 is comprised at least from the resin base material and the metal layer provided in the outermost surface of one surface of the resin base material. This metal resin tape 14 is installed by making the metal layer side the side winding shield 13 side, and winding it horizontally. By doing in this way, even when a gap is generated in the transverse winding shield 13, since the thin wire of the transverse winding shield 13 and the metal layer of the metal resin tape 14 are in direct contact, a decrease in the shielding effect can be suppressed. In addition, "at least" or "the outermost surface" means that another layer may be arbitrarily provided between the resin substrate and the metal layer or on the other surface of the resin substrate.

The metal resin tape 14 is overlapped and wound in the range of 1/4 laps to 1/2 laps. By setting it as the wrap within this range, the contact of the metal layer which comprises the metal resin tape 14 and the transverse winding shield 13 can be ensured, and a stable shielding effect can be implement|achieved. When the lap is less than 1/4, the overlap is small, so there is a fear that the overlap is shifted during horizontal winding. can be detrimental Moreover, since the winding pitch of the metal resin tape 14 is set arbitrarily by the width|variety and lap|wrap of the metal resin tape 14, it is although it does not specifically limit, The width of the metal resin tape 14 is about 3-6 mm, for example. When it is within the range, it is preferable that the winding pitch be in the range of 1.5-10 mm, for example. The transverse winding direction of the metal resin tape 14 may be the same winding direction as the transverse winding direction of the fine metal wire described above, or may be a winding direction in the opposite direction, but the opposite direction is preferable.

The transverse winding of the metal resin tape 14 is wound in an opposite state so that the metal layer side faces the fine metal wire so that the metal layer directly contacts the thin metal wire of the transverse winding shield 13 . As a result, by making the metal thin wire and the metal layer of the metal resin tape in direct contact, electrical conduction can be more stabilized, and a stable shielding characteristic can be ensured. By transverse winding under the wrap, there is no gap between the metal layers of the metal resin tape 14, so that the metal layer can be placed in direct contact with the thin metal wire. Moreover, since the metal resin tape 14 itself has the state of transverse winding being fixed by the adhesive layer which the resin tape 15 has, in this metal resin tape 14, the stress at the time of wiring of the coaxial cable 10 causes a metal thin wire. Even if the movement is slightly shifted, since the metal resin tape 14 provided thereon does not shift, stable shielding characteristics can be ensured.

Although the resin base material which comprises the metal resin tape 14 is not specifically limited, Polyester films, such as a polyethylene terephthalate and a polyethylene naphthalate, can be used preferably. The thickness of the resin substrate is arbitrarily selected within a range of, for example, about 2 to 16 µm.

As for the metal layer which comprises the metal resin tape 14, a copper layer, an aluminum layer, etc. are mentioned as a preferable thing. The metal layer is preferably a metal layer formed by vapor deposition or plating on a resin substrate, or a metal foil bonded through an adhesive layer provided as necessary (eg, polyester-based thermoplastic adhesive resin, etc.). The thickness of the metal layer is not particularly limited, and the thickness of the metal layer varies depending on the forming means, but the thickness of the metal layer can be arbitrarily selected within the range of about 2 to 8 µm by vapor deposition or plating.

It is preferable that the thickness of the metal resin tape 14 exists in the range of about 8-18 micrometers. By setting it in this range, it can contribute to the thinning of the coaxial cable 10.

(cortex)

The shell bodies 15 and 16 are provided on the outer periphery of the shell conductors 13 and 14, and, in detail, are provided on the metal resin tape 14, as shown in FIG. The outer shells 15 and 16 are composed of a resin tape 15 wound on a metal resin tape 14 and an extruded sheath 16 covering the resin tape 15 . The material of these resin tapes 15 and the extruded sheath 16 is not particularly limited as long as they have insulating properties. The resin tape 15 is a resin tape which has an adhesive layer on one surface, and is spirally wound on the metal resin tape 14, and is provided. The extruded sheath 16 is an insulating sheath provided by extruding resin.

(resin tape)

The resin tape 15 is installed by transverse winding (spiral winding) on the metal resin tape 14, as shown in FIG. The resin tape 15 is composed of at least a resin substrate and an adhesive layer provided on the outermost surface of one surface of the resin substrate. This resin tape 15 is installed by transversely winding the adhesive layer side toward the metal resin tape 14 side. Since the resin tape 15 and the metal resin tape 14 are adhesively fixed by doing in this way, even when stress is applied at the time of wiring, the metal resin tape 14 does not shift|deviate. As a result, it is possible to suppress a decrease in the shielding effect acting as the metal resin tape 14 and the transverse winding shield 13 . In addition, "at least" or "the outermost surface" means that another layer may be arbitrarily provided between the resin substrate and the adhesive layer or on the other surface of the resin substrate. In addition, an adhesive layer is not provided on the other side, and it is not adhered to the extrusion sheath 16 formed thereon, so, for example, when stress is applied during wiring, the resin tape 15 and the extrusion sheath 16 are not provided. There is also an advantage in that the flexure becomes flexible due to the occurrence of sliding at the interface.

The resin tape 15 is overlapped and wound in the range of 1/4 laps to 1/2 laps, similarly to the metal resin tape 14 described above. By setting it as a wrap within this range, the adhesive layer constituting the resin tape 15 can fix the resin tape 15 itself, and it can be adhered to the metal resin tape 14 to fix the metal resin tape 14. can If the lap is less than 1/4, the overlap is small, so there is a fear that the overlap is shifted during horizontal winding. can In addition, although the winding pitch of the resin tape 15 is arbitrarily set by the width|variety and lap|wrap of the resin tape 15, when the width of the resin tape 15 is in the range of about 3-6 mm, for example, the winding pitch is For example, it is preferable to become in the range of 1.5-10 mm. The transverse winding direction of the resin tape 15 may be the same winding direction as the transverse winding direction of the metal resin tape 14 described above, or may be a winding direction in the opposite direction, but the opposite direction is preferable.

In the coaxial cable 10 according to the present invention, when the thickness of the resin tape 15 is T2 and the thickness of the metal resin tape 14 is T1, T2/T1 is 1/4 (=0.25) or more and 4 /5 (=0.8) or less. By doing in this way, the level difference can be made small (about 7 micrometers or less) compared with the case where only the metal resin tape 14 is used. Therefore, it is possible to suppress the appearance irregularities caused by the air present in the level difference. As a result, changes in the outer diameter in the longitudinal direction can be suppressed, and terminal processing can be performed under the same conditions when connecting the terminal to the connector.

When T2/T1 is greater than 1/2, a level difference also occurs in the resin tape 15, so that a sufficient improvement effect may not be obtained. When T2/T1 is smaller than 1/4, the resin tape 14 is too thin and the degree of the level difference of the metal resin tape 14 remains as it is, and a sufficient improvement effect may not be obtained. The size of the step that affects the appearance varies depending on the overall outer diameter. For example, when a step of 10 µm or more occurs, the unevenness of the appearance becomes conspicuous. Therefore, it is preferable that the step difference of less than 10 µm is the limit. do. Moreover, the thickness T2 of the resin tape 15 satisfies the relationship of "T2/T1 = 1/4 - 4/5" (0.25 - 0.8), and specifically 4 micrometers or more and less than 10 micrometers, detailed Preferably, the thickness is 4 µm or more and 9 µm or less.

Although the resin base material which comprises the resin tape 15 is not specifically limited, For example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide (PA), polyimide (PI), polyphenylene sulfide (PPS), ethylene-4 fluorinated ethylene copolymer (ETFE), tetrafluorinated ethylene-6 fluorinated propylene copolymer (FEP), fluorinated resin copolymer (perfluoroalkoxy fluororesin: PFA), polyether ether ketone (PEEK) etc. are mentioned. In particular, polyester films, such as a polyethylene terephthalate and a polyethylene naphthalate, can be used preferably. The thickness of the resin substrate is arbitrarily selected within the range of, for example, about 2 to 6 µm.

The adhesive layer constituting the resin tape 15 is provided on one surface of the resin substrate, and examples of the material include a urethane-based adhesive, an epoxy-based adhesive, and an acrylic adhesive. Although the thickness of a contact bonding layer is not specifically limited, either, It can be set as about 1-3 micrometers.

(extrusion sheath)

The extrusion sheath 16 is provided on the resin tape 15 by extrusion molding. As the constituent resin of the extruded sheath 16, various resins applied to the extruding resin for the outer shell can be used. For example, fluorine resin, such as PFA, ETFE, and FEP, may be sufficient, vinyl chloride resin may be sufficient, polyolefin resin, such as polyethylene, and polyester resin, such as polyethylene terephthalate, may be sufficient. In the coaxial cable 10 according to the present invention, it is preferable that it is a fluororesin.

When providing the extrusion sheath 16, it is preferable to perform extrusion molding while suctioning with a vacuum pump so that no air remains between the resin tape 15 and the resin tape 15 as much as possible. The total thickness of the outer shell composed of the extruded sheath 16 and the resin tape 15 can be, for example, in the range of about 0.1 to 1.0 mm.

The final outer diameter of the obtained coaxial cable 10 is preferably in the range of about 0.6 to 3.5 mm. Such a coaxial cable 10 can suppress the appearance unevenness|corrugation, can suppress the outer diameter change in the longitudinal direction, and can terminal-process under the same conditions when connecting a terminal to a connector. Moreover, while being able to implement|achieve narrower diameter compared with a braided shield, even when a gap arises in a transverse winding shield, the fall of a shielding effect can be suppressed. As a result, it is possible to realize a narrow width that can realize in-device wiring in a narrow space, and is particularly suitable for in-device antenna wiring or semiconductor devices conforming to the 5th generation communication standard (5G).

[Example]

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited to the following example.

[Example 1]

First, the coaxial cable 10 of the form shown in FIG. 1 was produced. As the central conductor 11, a silver-plated annealed copper wire having an outer diameter of 0.203 mm was used. Next, on the outer periphery of the central conductor 11, PFA resin (manufactured by DuPont, dielectric constant 2.1) having a thickness of 0.21 mm was extruded so as to have the solid structure shown in Fig. 2A, and the outer diameter was 0.623 mm. Next, a transverse winding shield 13 and a metal resin tape 14 were provided as external conductors. The transverse winding shield 13 was formed so as to be a single layer on the insulator 12 . Specifically, 38 silver-plated annealed copper wires having an outer diameter of 0.05 mm were wound to the left at a pitch of 6.5 mm. The outer diameter after formation was 0.780 mm. Next, the metal resin tape 14 was wound on the transverse winding shield 13 . As the metal resin tape 14, a copper foil having a thickness of 4 μm was provided on one side of a PET base material having a thickness of 8 μm, and a total thickness of 12 μm and a width of 3 mm was used. This metal resin tape 14 was wound in a direction opposite to that of the transverse winding shield 13 in 1/3 wrap (overlapping only the width of 1 mm) so that the copper foil side was inside (the side of the transverse winding shield 13).

Next, on the metal resin tape 14, a resin tape 15 having a total thickness of 4 μm and a width of 3 mm provided on one side with an adhesive layer having a thickness of 1 μm, the adhesive layer side is inside (the side of the metal resin tape 14) I wrapped it up to make it this way. The winding form is 1/3 wrap (only the width of 1 mm overlaps), and it wound in the reverse direction with the metal resin tape 14. It was heated just before the winding process to adhere the adhesive layer and the metal resin tape 14 . Then, as the extruded sheath 16, a layer of PFA resin (manufactured by DuPont) was extruded to a thickness of 50 µm while suctioning with a vacuum pump to prepare a coaxial cable 10 having an outer diameter of 0.880 mm. In this coaxial cable 10, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=4/12=0.333.

[Example 2]

In Example 1, as the resin tape 15, a resin tape having a total thickness of 6 µm and a width of 3 mm in which an adhesive layer having a thickness of 1 µm was provided on one side was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of Example 2 used as an outer diameter of 0.888 mm. In this coaxial cable 10, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=6/12=0.500.

[Example 3]

In Example 1, as the resin tape 15, a resin tape having a total thickness of 3 µm and a width of 3 mm in which an adhesive layer having a thickness of 1 µm was provided on one side was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of Example 3 used as an outer diameter of 0.879 mm. In this coaxial cable 10, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=3/12=0.250.

[Example 4]

In Example 1, as the resin tape 15, a resin tape having a total thickness of 8 µm and a width of 3 mm in which an adhesive layer having a thickness of 1 µm was provided on one side was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable 10 of Example 4 used as an outer diameter of 0.894 mm. In this coaxial cable, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=8/12=0.666.

[Example 5]

In Example 1, a metal resin tape 14 having a total thickness of 16 µm and a width of 3 mm in which a copper foil having a thickness of 4 µm was provided on one side of a 12 µm-thick PET base material was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of Example 5 used as an outer diameter of 0.890 mm. In this coaxial cable 10, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=4/16=0.250.

[Example 6]

In Example 1, a metal resin tape 14 having a total thickness of 10 µm and a width of 3 mm in which a copper foil having a thickness of 4 µm was provided on one side of a PET base material having a thickness of 6 µm was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of Example 6 used as an outer diameter of 0.872 mm. In this coaxial cable 10, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=4/10=0.400.

[Example 7]

In Example 1, the insulator 12 was made into a hollow structure. The hollow structure is formed by extruding a PFA resin (manufactured by DuPont) at 350° C. with a die nipple for forming a hollow structure, and the voids have an inner annular portion 12a having a thickness of 0.05 mm, an outer annular portion 12b having a thickness of 0.05 mm and a thickness A hollow structure having a cross-sectional shape surrounded by a 0.05 mm connection portion 12c was molded, and the porosity was 54%. Other than that, it carried out similarly to Example 1, and produced the coaxial cable 10 of Example 7.

[Comparative Example 1]

In Example 1, the resin tape 15 was not provided. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of Comparative Example 1.

[Comparative Example 2]

In Example 1, as the resin tape 15, a resin tape having a total thickness of 10 µm and a width of 3 mm in which an adhesive layer having a thickness of 1 µm was provided on one side was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of the comparative example 2 used as an outer diameter of 0.900 mm. In this coaxial cable, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=10/12=0.833.

[Comparative example 3]

In Example 1, as the resin tape 15, a resin tape having a total thickness of 2 µm and a width of 3 mm in which an adhesive layer having a thickness of 1 µm was provided on one side was used. Other than that, it carried out similarly to Example 1, and produced the coaxial cable of the comparative example 3 used as an outer diameter of 0.876 mm. In this coaxial cable, the thickness T2 of the resin tape 15 and the thickness T1 of the metal resin tape 14 are T2/T1=2/12=0.166.

[evaluation]

Steps and appearance were visually evaluated. The step was mainly formed by the tape of the uppermost layer, and Examples 1, 5, 6, and 7 were 4 μm, Example 2 was 6 μm, Example 3 was 3 μm, and Example 4 was 8 μm, and Comparative Example 1 was 12 µm, Comparative Example 2 was 10 µm. Moreover, in Comparative Example 3, the thickness of the resin tape 15 of the uppermost layer is as thin as 2 micrometers, the influence of the metal resin tape 14 with a thickness of 12 micrometers below it is large, and the step difference of about 8-7 micrometers as a whole. had arisen

The appearance of the final coaxial cable after installing the extruded sheath 16 was small in Examples 1 to 7, but compared with Comparative Examples 1 to 3, and the terminal processing was also possible under the same conditions. As described above, it was visually confirmed that the air layer became small by reducing the step, the appearance was improved, and the curvature (external diameter fluctuation) in the longitudinal direction was reduced.

10 coaxial cable
11 center conductor
12 insulator
12a inner annular upper part
12b outer annulus
12c connection
12' void
13 transverse winding shield
14 Metal Resin Tape
15 resin tape
16 Extrusion Sheath

Claims (5)

A coaxial cable comprising: a central conductor; a transverse winding shield provided by winding a thin metal wire horizontally on the It is composed of an extruded sheath covering the tape, and when the thickness of the resin tape is T2 and the thickness of the metal resin tape is T1, T2/T1 is in the range of 1/4 or more and 4/5 or less. coaxial cable. The coaxial cable according to claim 1, wherein the metal resin tape has a thickness of 8 µm or more and 18 µm or less, and the resin tape has a thickness of 4 µm or more and 9 µm or less. The coaxial cable according to claim 1 or 2, wherein the metal resin tape and the resin tape are overlapped in the range of 1/4 wrap to 1/2 wrap. The coaxial cable according to claim 1 or 2, wherein an adhesive layer is provided on one side of the resin tape, and the adhesive layer is wound inside. The coaxial cable according to claim 3, wherein an adhesive layer is provided on one side of the resin tape, and the adhesive layer is wound inside.

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