Dielectric waveguide cable and terminal structure of dielectric waveguide cable

Abstract

The invention provides a dielectric waveguide cable capable of reducing transmission loss and a tail end structure of the dielectric waveguide cable capable of suppressing reflection of an end portion of the dielectric waveguide cable. A dielectric waveguide cable (1) has a core (2) formed from a dielectric, and a cavity (20) extending in the longitudinal direction of the cable is formed in the center of the core (2) in a cross section perpendicular to the longitudinal direction of the cable. In a terminal structure of a dielectric waveguide cable (1), a terminal member (5) having a conical portion (52) and the dielectric waveguide cable are arranged side by side, a shaft hole (50) having a reduced diameter portion (502b) whose inner diameter decreases toward a tip portion of the conical portion (52) is formed in the terminal member (5), and a cavity (20) of the dielectric waveguide cable communicates with the shaft hole (50) of the terminal member (5). Alternatively, at least one linear dielectric (23) having a smaller outer diameter than the inner diameter of the cavity (20) is housed in the cavity (20) at the end of the dielectric waveguide cable (1).

Description

Technical Field

[0001] The present invention relates to a dielectric waveguide cable having a waveguide formed of a dielectric and an end structure of the dielectric waveguide cable. Background Art

[0002] In the prior art, in order to transmit high-frequency signals such as millimeter waves, a dielectric with a high dielectric constant and a low dielectric loss tangent is used as a signal transmission medium. In the dielectric waveguide circuit described in Patent Document 1, a resin such as PTFE (polytetrafluoroethylene) is used as a signal transmission medium. In addition, Patent Document 1 describes that the dielectric waveguide circuit is composed of a dielectric waveguide circuit body having a circular cross-section and a dielectric waveguide circuit end formed in a conical shape, and a part of the dielectric waveguide circuit body is embedded in an embedding hole provided in a connector.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2018 / 216636 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In recent years, with the high speed of mobile communications, a dielectric waveguide cable capable of transmitting higher frequency signals over long distances has been required. In order to enable long-distance transmission of high-frequency signals, reducing the transmission loss in the dielectric waveguide cable has become a problem. In addition, suppressing the reflection at the end of the dielectric waveguide cable has also become an important problem. Therefore, the object of the present invention is to provide a dielectric waveguide cable capable of reducing the transmission loss, and a terminal structure of a dielectric waveguide cable capable of suppressing the reflection at the end of the dielectric waveguide cable.

[0008] Solutions to Solve Problems

[0009] The present invention aims to solve the above-mentioned problems and provides a dielectric waveguide cable having a core formed of a dielectric, wherein electromagnetic waves in the GHz frequency band are transmitted through the core, and a cavity extending along the length direction of the cable is formed in the center of the core in a cross section perpendicular to the length direction of the cable.

[0010] In addition, the present invention aims to solve the above-mentioned problems and provides an end structure of a dielectric waveguide cable, wherein the dielectric waveguide cable transmits electromagnetic waves in the GHz frequency band using a core formed by a dielectric, and the end component and the dielectric waveguide cable are arranged in such a manner that the central axis of the end component composed of a dielectric having a conical portion is consistent with the central axis of the dielectric waveguide cable, in which a cavity extending along the length direction of the cable is formed in the central portion of the core in a cross section perpendicular to the length direction of the cable, and an axial hole having a reduced diameter portion whose inner diameter decreases toward the front end portion of the conical portion is formed in the end component, and the cavity of the dielectric waveguide cable is connected to the axial hole of the end component.

[0011] In addition, the present invention aims to solve the above-mentioned problems and provides an end structure of a dielectric waveguide cable, wherein the dielectric waveguide cable transmits electromagnetic waves in the GHz frequency band using a core formed of a dielectric, and the end component and the dielectric waveguide cable are arranged in such a manner that the central axis of an end component having a conical portion and formed of a dielectric is consistent with the central axis of the dielectric waveguide cable, and in the dielectric waveguide cable, a cavity extending along the length direction of the cable is formed in the central portion of the core in a cross section perpendicular to the length direction of the cable, and at least one linear dielectric having an outer diameter smaller than the inner diameter of the cavity is accommodated in the cavity at the end portion of the core on the end component side.

[0012] Effects of the Invention

[0013] According to the dielectric waveguide cable of the present invention, transmission loss can be reduced. In addition, according to the terminal structure of the dielectric waveguide cable of the present invention, reflection at the end of the dielectric waveguide cable can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 (a) is a perspective view showing a configuration example of a dielectric waveguide cable according to an embodiment of the present invention. (b) is a cross-sectional view taken along line AA of (a).

[0015] Figure 2 (a) is a graph showing the analysis result of the relationship between the inner and outer diameter ratio and the transmission loss in a dielectric waveguide having a cavity at the center. (b) is a cross-sectional view showing the dielectric waveguide used for the analysis.

[0016] Figure 3 (a) is a graph showing the results of measuring the transmission loss of the dielectric waveguide cable of the present embodiment and the dielectric waveguide cable of the comparative example at a transmission frequency of 28 GHz. (b) is a cross-sectional view showing the structure of the dielectric waveguide cable of the comparative example.

[0017] Figure 4This is a graph showing the results of measuring S21 at transmission frequencies ranging from 21 GHz to 40 GHz for a plurality of dielectric waveguide cables having different cable lengths.

[0018] Figure 5 (a) and (b) are structural diagrams showing a first structural example of the terminal structure of the dielectric waveguide cable.

[0019] Figure 6 (a) to (c) are structural diagrams showing a second structural example of the terminal structure of the dielectric waveguide cable.

[0020] Explanation of symbols

[0021] 1—dielectric waveguide cable, 2—core, 20—cavity, 21—dielectric waveguide tube, 22—dielectric waveguide wire, 23—linear dielectric, 3—jacket, 31—rolled tape, 32—sheath, 5, 5A—end component, 50—axial hole, 502—thin-diameter portion, 502b—reduced-diameter portion, 51—cylindrical portion, 52—conical portion, C1, C5—center axis. DETAILED DESCRIPTION

[0022] [Implementation Method]

[0023] Figure 1 (a) is a perspective view showing a configuration example of a dielectric waveguide cable 1 according to an embodiment of the present invention. Figure 1 (b) is Figure 1 (a) AA line cross-sectional view. Figure 1 (a) shows the end of the dielectric waveguide cable 1 in a delaminated state. Figure 1 In (a) and (b), the central axis C1 of the dielectric waveguide cable 1 is indicated by a dashed line. Hereinafter, the direction along the central axis C1 of the dielectric waveguide cable 1 is referred to as a cable length direction. Figure 1 (b) shows a cross section of the dielectric waveguide cable 1 perpendicular to the longitudinal direction of the cable.

[0024] The dielectric waveguide cable 1 is configured to include a core 2 which is a waveguide formed of a dielectric and a jacket 3 provided on the outer periphery of the core 2, and electromagnetic waves in the GHz band are transmitted by the core 2. The dielectric waveguide cable 1 of this embodiment is particularly suitable for the transmission of electromagnetic waves in the range of 20 GHz to 100 GHz, but can also be used for the transmission of electromagnetic waves in the range of 100 GHz to 300 GHz.

[0025] The dielectric material constituting the core 2 is such that the dielectric loss tangent at the frequency of the electromagnetic wave transmitted by the dielectric waveguide cable 1 is less than 1×10 -3Here, dielectric loss tangent (also called tanδ, tangent δ or dielectric loss tangent) is an index value indicating the ratio of a part of the energy of a dielectric to heat when an AC electric field is applied to the dielectric, and the smaller the loss, the smaller the value of dielectric loss tangent. More specifically, as the resin constituting the core 2, for example, any one of fluororesin, foamed fluororesin, polyethylene, foamed polyethylene, polypropylene, and foamed polypropylene can be used.

[0026] A cavity 20 extending along the length direction of the cable is formed in the center of the core 2 in a cross section perpendicular to the length direction of the cable. The cavity 20 is filled with air (atmosphere). The dielectric loss tangent of air is generally lower than that of resin, and the electromagnetic waves transmitted by the core 2 propagate more in the center, so the cavity 20 is formed in the center of the core 2 to reduce the loss.

[0027] like Figure 1 As shown in (b), when the cable outer diameter of the dielectric waveguide cable 1 is set to D1 and the inner diameter of the cavity 20 is set to Di, the ratio (Di / D1) of the inner diameter Di of the cavity 20 to the cable outer diameter D1 is greater than 20% and less than 40%. If Di / D1 is less than 20%, the cross-sectional area of ​​the cavity 20 in the cross section perpendicular to the length direction of the cable becomes smaller, and the effect of reducing the loss becomes smaller. In addition, if Di / D1 is greater than 40%, the thickness of the dielectric waveguide cable 1 outside the cavity 20 becomes smaller, the effect of confining the electromagnetic wave inside the waveguide becomes smaller, and the electromagnetic wave is radiated to the outside of the dielectric waveguide cable 1, and the loss becomes larger. Therefore, in the range of Di / D1 being greater than 20% and less than 40%, the effect of suppressing the loss becomes larger. As an example, the cable outer diameter D1 of the dielectric waveguide cable 1 is 10.08 mm, and as an example, the inner diameter Di of the cavity 20 is 3.00 mm.

[0028] In this embodiment, the core 2 is configured to include a dielectric waveguide 21 and a plurality of dielectric waveguide lines 22 arranged around the dielectric waveguide 21. The dielectric waveguide 21 is a hollow tube having a cavity 20 formed in the center. The outer diameter D of the dielectric waveguide 21 is 21 As an example, it is 4.00 mm. The plurality of dielectric waveguide wires 22 are twisted into a spiral shape at an angle with respect to the cable longitudinal direction. The structure of the core 2 improves the flexibility of the dielectric waveguide cable 1.

[0029] The dielectric waveguide 21 and the plurality of dielectric waveguide wires 22 are each composed of a dielectric loss tangent less than 1×10 -3In order to maintain the shape of the dielectric waveguide 21, the resin material of the dielectric waveguide 21 is preferably harder than the resin material of the dielectric waveguide 22. In the present embodiment, the dielectric waveguide 21 is made of PTFE (polytetrafluoroethylene), and the dielectric waveguide 22 is made of FEP (tetrafluoroethylene-hexafluoropropylene copolymer).

[0030] like Figure 1 As shown in (a) and (b), the core 2 is a core 2 in which 30 dielectric waveguide wires 22 are twisted in a spiral shape in a two-layer structure of inner and outer layers on the outer periphery of a dielectric waveguide 21 disposed at the center. The 12 dielectric waveguide wires 22 located in the inner layer of the 30 dielectric waveguide wires 22 are disposed in contact with the outer peripheral surface 21a of the dielectric waveguide 21, which is equivalent to the 18 dielectric waveguide wires 22 in the outer layer being disposed on the outer peripheral side of the 12 dielectric waveguide wires 22 located in the inner layer. In this embodiment, as Figure 1 As shown in (a), the spiral winding direction of the 12 dielectric waveguide wires 22 corresponding to the inner layer is the same as the spiral winding direction of the 18 dielectric waveguide wires 22 corresponding to the outer layer, but the winding directions of the plurality of dielectric waveguide wires 22 in the inner layer and the outer layer may be opposite. When the spiral winding directions of the inner layer and the outer layer are the same, the dielectric waveguide cable 1 is easy to bend. When the spiral winding directions of the inner layer and the outer layer are opposite, the twist of the plurality of dielectric waveguide wires 22 is difficult to loosen, so it is easy to obtain the effect of confining the transmitted electromagnetic waves inside the waveguide.

[0031] The cross section of each dielectric waveguide 22 perpendicular to the longitudinal direction is circular, and its outer diameter D 22 For example, it is 1.33 mm. The diameter D2 of the core 2 is set as the outer diameter D 21 The diameter D2 of the core 2 is obtained by adding the outer diameter D22 of the plurality of dielectric waveguides 22. In the present embodiment, the diameter D2 of the core 2 is obtained by adding the outer diameter D22 of the dielectric waveguide 21 to the outer diameter D22 of the dielectric waveguide 21. 21 Add the outer diameter D of the dielectric waveguide 22 of 4 22 As an example, the outer diameter D of the dielectric waveguide 21 is 21 The outer diameter D of the dielectric waveguide 22 is 4.00 mm. 22 When the inner diameter Di of the cavity 20 of the dielectric waveguide 21 is 3.00 mm and the diameter D2 of the core 2 is 9.32 mm, the ratio (Di / D2) of the inner diameter Di of the cavity 20 to the diameter D2 of the core 2 is preferably within the range of Di / D2 (i.e., 20% or more and 40% or less). As an example, when the inner diameter Di of the cavity 20 of the dielectric waveguide 21 is 3.00 mm and the diameter D2 of the core 2 is 9.32 mm, the ratio is approximately 32%.

[0032] The jacket 3 is composed of a band-shaped compression tape 31 wound around the periphery of a collection of multiple (30 in the present embodiment) dielectric waveguide wires 22 and a sheath 32 covering the compression tape 31. The compression tape 31 is spirally wound around the core 2 in a manner that a portion of the width direction overlaps. The compression tape 31 can be used to prevent multiple dielectric waveguide wires 22 from spreading out during the manufacturing process of the dielectric waveguide cable 1. In addition, the sheath 32 is used to protect the core 2 and the compression tape 31. The sheath 32 is formed on the periphery of the compression tape 31 by extrusion molding. The compression tape 31 is sandwiched between the sheath 32 and the core 2, so that the sheath 32 is easily molded and the bendability of the dielectric waveguide cable 1 is improved. In addition, the jacket 3 only needs to be composed of at least one of the compression tape 31 and the sheath 32.

[0033] The dielectric loss tangent value of the material of the compression tape 31 and the sheath 32 can be higher than that of the dielectric waveguide 21 and the dielectric waveguide 22, but the strength is preferably higher than that of the material of the dielectric waveguide 21 and the dielectric waveguide 22. The electromagnetic wave transmitted by the dielectric waveguide cable 1 is mainly transmitted in the core 2, but a part of it can also be transmitted in the compression tape 31 and the sheath 32. The compression tape 31 is composed of a sealing tape composed of a fluororesin such as PTFE, for example. The sheath 32 is composed of a fluororesin such as FEP, and it is especially preferable to use a material with excellent wear resistance and crack resistance. The thickness of the compression tape 31 is, for example, more than 0.07 mm and less than 0.09 mm, and the thickness of the sheath 32 is, for example, more than 0.25 mm and less than 0.35 mm.

[0034] Figure 2 (a) is a line graph showing the analytical results of the relationship between the inner and outer diameter ratio and the transmission loss in a dielectric waveguide having a cavity at the center. In this analysis, Figure 2 As shown in (b), a dielectric waveguide 4 having a cavity 40 at the center is used, and the inner diameter D of the cavity 40 is 40 The transmission loss per 1 m length of the dielectric waveguide 4 was analyzed for a plurality of different samples. The outer diameter D4 of the dielectric waveguide 4 was 10 mm, and as the material of the dielectric waveguide 4, a dielectric loss tangent of 3×10 -4 The vertical axis of the graph is the transmission loss (dB / m) when the 28 GHz electromagnetic wave is transmitted by the dielectric waveguide 4, and the horizontal axis of the graph is the D 40 / D4 represents the inner and outer diameter ratio of the dielectric waveguide 4. The sample with a value of 0 on the horizontal axis is a sample of a solid structure in which the cavity 40 is not formed.

[0035] As shown in the graph, the transmission loss of the dielectric waveguide 4 is as small as 2.4 dB / m or less when the inner / outer diameter ratio is in the range of 0.2 to 0.4, and the transmission loss is the smallest when the inner / outer diameter ratio is 0.3. 40In the case where the inner diameter D is 3 mm, the transmission loss is improved by 0.34 dB / m compared to the case where the cavity 40 is not formed. 40 By adjusting the ratio to the outer diameter D4 to an appropriate value, the transmission loss can be reduced compared to the case where the cavity 40 is not formed.

[0036] Figure 3 (a) is for the dielectric waveguide cable 1 and Figure 3 The dielectric waveguide cable 1A of the comparative example shown in (b) is a graph showing the result of measuring the transmission loss when the transmission frequency is 28 GHz. The dielectric waveguide cable 1A of the comparative example has 7 dielectric waveguide wires 22 arranged at the center instead of the dielectric waveguide wires 21 of the dielectric waveguide cable 1 of the embodiment, and the core 2A is composed of a total of 37 dielectric waveguide wires 22. The outer diameter D of the dielectric waveguide cable 1A is 1A , the diameter D of the core 2A in the dielectric waveguide cable 1A 2A and the outer diameter D of the dielectric waveguide 22 22 The outer diameter D1 of the dielectric waveguide cable 1, the diameter D2 of the core 2, and the outer diameter D 22 same.

[0037] like Figure 3 As shown in the diagram of (a), the dielectric waveguide cable 1 of the embodiment has a cavity 20 formed in the center portion of the core 2, and thus has a lower loss than the dielectric waveguide cable 1A of the comparative example.

[0038] Figure 4 : is a graph showing the results of measuring S21 (transmission coefficient from the input end to the output end) at a transmission frequency of 21 GHz to 40 GHz for dielectric waveguide cables 1 having cable lengths of 2 m, 4 m, 6 m, 8 m, and 10 m. Figure 4 As shown, the dielectric waveguide cable 1 has a tendency that the longer the cable length is and the higher the transmission frequency is, the smaller S21 is and the larger the transmission loss is, but the transmission loss is suppressed to be small as a whole.

[0039] Next, we will refer to Figure 5 as well as Figure 6 Two configuration examples of the terminal structure of the dielectric waveguide cable 1 will be described.

[0040] Figure 5 (a) and (b) are structural diagrams showing a first structural example of the terminal structure of the dielectric waveguide cable 1. In the first structural example, the dielectric waveguide cable 1 is connected to the connector 6 via a hollow terminal component 5. A coaxial waveguide conversion part 7 is mounted on the connector 6, and a coaxial cable 9 is connected to the coaxial waveguide conversion part 7 via a coaxial connector 8.

[0041] exist Figure 5 In (a), the dielectric waveguide cable 1, the terminal member 5, and the connector 6 are arranged separately in the axial direction. Figure 5 (b) shows the state in which the dielectric waveguide cable 1, the terminal component 5, and the connector 6 are combined. The dielectric waveguide cable 1 and the terminal component 5 are arranged in the axial direction so that the central axis C1 of the dielectric waveguide cable 1 coincides with the central axis C5 of the terminal component 5. Figure 5 In (a) and (b), cross sections of the dielectric waveguide cable 1 and the terminal member 5 are shown above the central axes C1 and C5, and appearances of the dielectric waveguide cable 1 and the terminal member 5 are shown below the central axes C1 and C5.

[0042] In the dielectric waveguide cable 1, at one end portion on the connector 6 side, 18 dielectric waveguide wires 22 corresponding to the outer layer are cut together with the crimping tape 31 and the sheath 32 covering them at the first end surface portion 1a, and 12 dielectric waveguide wires 22 corresponding to the inner layer are cut together with the dielectric waveguide tube 21 at the second end surface portion 1b on the connector 6 side relative to the first end surface portion 1a. The 12 dielectric waveguide wires 22 and the dielectric waveguide tube 21 between the first end surface portion 1a and the second end surface portion 1b form a fitting portion 10 that fits with the terminal member 5.

[0043] The terminal member 5 is formed by a dielectric loss tangent less than 1×10 -3 The end member 5 has a cylindrical portion 51 and a conical portion 52 in one piece, and the cylindrical portion 51 and the conical portion 52 are arranged in the axial direction along the central axis C5. The cylindrical portion 51 has an outer diameter D 51 The conical portion 52 has a constant cylindrical shape in the entire length direction. 52 The outer diameter D of the cylindrical portion 51 is gradually reduced toward the front end. 51 The outer diameter D1 of the conical portion 52 is equal to the outer diameter D1 of the dielectric waveguide cable 1. 52 The end portion on the cylindrical portion 51 side and the outer diameter D of the cylindrical portion 51 51 The angle θ of the conical portion 52 is equal to the angle θ of the cylindrical portion 51 and gradually decreases as the angle θ increases in the axial direction away from the cylindrical portion 51. The cone angle θ of the conical portion 52 is, for example, not less than 5° and not more than 15°.

[0044] The terminal member 5 is provided with an axial hole 50 centered on the central axis C5. The axial hole 50 is composed of a fitting portion 501 to which the fitting portion 10 of the dielectric waveguide cable 1 is fitted, a thin-diameter portion 502 having an inner diameter smaller than that of the fitting portion 501, and a tapered portion 503 between the fitting portion 501 and the thin-diameter portion 502. The fitting portion 501, the thin-diameter portion 502, and the tapered portion 503 are arranged along the central axis C5 of the terminal member 5, and the thin-diameter portion 502 is formed on the front end side of the conical portion 52 relative to the fitting portion 501. The fitting portion 501, the thin-diameter portion 502, and the tapered portion 503 in the cross section perpendicular to the central axis C5 of the terminal member 5 are each circular. The inner diameter of the tapered portion 503 gradually decreases from the fitting portion 501 side toward the thin-diameter portion 502 side.

[0045] The length of the fitting portion 501 in the axial direction of the terminal member 5 is equal to the length of the fitting portion 10 of the dielectric waveguide cable 1. The first end surface portion 1a of the dielectric waveguide cable 1 abuts against the rear end surface 5a of the terminal member 5 facing the first end surface portion 1a. The dielectric waveguide cable 1 and the terminal member 5 are wound together by adding a tape member of the same material as the pressure-wound tape 31 or fixed by a fixing member so that the fitting portion 10 of the dielectric waveguide cable 1 does not fall off from the fitting portion 501 of the terminal member 5.

[0046] The fitting portion 501 and the tapered portion 503 are formed in the cylindrical portion 51. A part of the small diameter portion 502 is formed in the center of the cylindrical portion 51, and the remaining part is formed in the center of the tapered portion 52. The small diameter portion 502 includes a cylindrical hole portion 502a having a constant inner diameter and a reduced diameter portion 502b having an inner diameter that decreases toward the front end of the tapered portion 52. The cylindrical hole portion 502a is formed in the center of the cylindrical portion 51, and the reduced diameter portion 502b is formed in the center of the tapered portion 52. The inner diameter of the cylindrical hole portion 502a is equal to the inner diameter of the cavity 20 of the dielectric waveguide 21. The inner diameter of the reduced diameter portion 502b is equal to the inner diameter of the cylindrical hole portion 502a at the end portion on the cylindrical hole portion 502a side, and gradually decreases as it moves away from the cylindrical hole portion 502a in the axial direction.

[0047] The connector 6 has a main body 61 and a mounting portion 62, and the mounting portion 62 is mounted on the main body 61 by a plurality of bolts 63. The main body 61 is formed with a housing hole 610 for housing a part of the cylindrical portion 51 and the conical portion 52 of the terminal component 5. The mounting portion 62 is formed with an insertion hole 620 for inserting the terminal component 5, and a holding member 64 for holding the cylindrical portion 51 of the terminal component 5 is arranged inside the insertion hole 620. The holding member 64 is made of resin, for example, PTFE.

[0048] The fitting portion 10 of the dielectric waveguide cable 1 is fitted with the fitting portion 501 of the terminal member 5, so that the dielectric waveguide cable 1 and the terminal member 5 are coaxially connected along the central axis C1 of the dielectric waveguide cable 1 and the central axis C5 of the terminal member 5, and the cavity 20 of the dielectric waveguide cable 1 is communicated with the axial hole 50 of the terminal member 5. The electromagnetic wave propagating toward the terminal member 5 side along the cavity 20 of the dielectric waveguide 21 in the dielectric waveguide cable 1 is emitted from the cavity 20 at the second end surface portion 1b and is incident on the thin-diameter portion 502 of the axial hole 50 of the terminal member 5, and is incident on the coaxial waveguide conversion portion 7 via the terminal member 5.

[0049] In the first structural example of the terminal structure, the reduced diameter portion 502b is formed in the axial hole 50 of the terminal member 5, thereby suppressing the reflection of the electromagnetic wave at the terminal portion of the dielectric waveguide cable 1. That is, if the small diameter portion 502 is not formed in the terminal member 5, the ratio of the electromagnetic wave reflected at the end face of the terminal member 5 facing the opening of the cavity 20 becomes large, but in the first structural example of the terminal structure, the small diameter portion 502 having the reduced diameter portion 502b is formed in the terminal member 5, so the cross-sectional shape of the dielectric waveguide cable 1 and the terminal member 5 is continuous, and the electric field distribution and magnetic field distribution of the transmitted electromagnetic wave are also substantially the same, so the reflectivity at the end face of the terminal member 5 can be suppressed.

[0050] Figure 6 (a) to (c) are structural diagrams showing a second structural example of the terminal structure of the dielectric waveguide cable 1. Figure 6 In (a), the dielectric waveguide cable 1, the terminal member 5A and the connector 6 are arranged separately in the axial direction. Figure 6 (b) shows a state where the dielectric waveguide cable 1, the terminal member 5A, and the connector 6 are assembled. Figure 6 (c) is Figure 6 (b) is a cross-sectional view of the BB line. Figure 6 In (a) to (c) of Figure 5 Parts that are common to the parts described in (a) and (b) are marked with Figure 5 The same symbols are used for (a) and (b), and repeated descriptions are omitted.

[0051] In the second configuration example, the dielectric waveguide cable 1 is connected to the connector 6 via the terminal member 5A. The dielectric waveguide cable 1 and the terminal member 5A are arranged in the axial direction so that the central axis C1 of the dielectric waveguide cable 1 coincides with the central axis C5 of the terminal member 5A. The terminal member 5A is made of a fluororesin such as PTFE, similarly to the terminal member 5 in the first configuration example, and has a cylindrical portion 51 and a conical portion 52 integrally. In addition, similarly to the fitting portion 501 of the axial hole 50 of the terminal member 5 in the first configuration example, a fitting hole 500 into which the fitting portion 10 of the dielectric waveguide cable 1 fits is formed in the terminal member 5A, but a hole corresponding to the small diameter portion 502 is not formed.

[0052] A linear dielectric 23 having an outer diameter smaller than the inner diameter of the cavity 20 is accommodated in the cavity 20 at the end portion on the terminal member 5A side of the core 2 of the dielectric waveguide cable 1. The linear dielectric 23 is similar to the dielectric waveguide tube 21 and the dielectric waveguide wire 22, and has a dielectric loss tangent less than 1×10 -3 In this example, Figure 6 As shown in (c), three linear dielectrics 23 are arranged in the cavity 20. However, the number of linear dielectrics 23 is not limited to three, and may be one, two, or four or more. That is, as long as at least one linear dielectric having an outer diameter smaller than the inner diameter of the cavity 20 is accommodated.

[0053] The length of the linear dielectric 23 is not particularly limited, and is, for example, 1 to 10 times the outer diameter of the dielectric waveguide cable 1. The linear dielectric 23 is arranged in a straight line parallel to the central axis C1 in the cavity 20. Figure 6 In the examples shown in (a) and (b), the end face 23a on the end component 5A side of the linear dielectric 23 is at the same position as the second end surface portion 1b, but the position of the end face 23a of the linear dielectric 23 can also be within the interlocking portion 10, and a portion of the linear dielectric 23 can also protrude from the dielectric waveguide 21 to the end component 5A side.

[0054] According to the second configuration example of the terminal structure, the reflection of the electromagnetic wave at the terminal portion of the dielectric waveguide cable 1 can also be suppressed. That is, in the second configuration example of the terminal structure, the axial hole 50 is not formed in the terminal component 5A, so the linear dielectric 23 is accommodated in the opening portion of the cavity 20, so that the cross-sectional shape of the dielectric waveguide cable 1 and the terminal component 5A is continuous, and the electric field distribution and magnetic field distribution of the propagating electromagnetic wave are similar, so the reflectivity is suppressed. The cross-sectional shape of the linear dielectric 23 accommodated in the cavity 20 on the side opposite to the terminal component 5A is discontinuous, but is arranged on the outside of the connector 6, so the change in the electric field distribution and magnetic field distribution of the propagating electromagnetic wave is small, and the reflectivity is suppressed.

[0055] (Summary of Implementation Methods)

[0056] Next, the technical ideas grasped from the above-described embodiments are described by citing the symbols in the embodiments. However, each symbol in the following description is not limited to specifically indicating the constituent elements in the claims as the components in the embodiments.

[0057] [1] A dielectric waveguide cable 1 having a core 2 formed of a dielectric, wherein the core 2 transmits electromagnetic waves in the GHz frequency band, wherein a cavity 20 extending along the length direction of the cable is formed at the center of the core 2 in a cross section perpendicular to the length direction of the cable.

[0058] [2] According to the dielectric waveguide cable 1 described in [1], the dielectric forming the core 2 has a dielectric loss tangent of less than 1×10 -3 of resin.

[0059] [3] In the dielectric waveguide cable 1 according to [2], a ratio of an inner diameter Di of the cavity 20 to a cable outer diameter D1 is 20% or more and 40% or less.

[0060] [4] According to the dielectric waveguide cable 1 described in any one of [1] to [3], the core 2 has a hollow dielectric waveguide tube 21 in which the cavity 20 is formed, and a plurality of dielectric waveguide tubes 22 arranged around the dielectric waveguide tube 21, and the plurality of dielectric waveguide tubes 22 are twisted in a spiral shape on the outer periphery of the dielectric waveguide tube 21.

[0061] [5] In the dielectric waveguide cable 1 according to [4], a roll tape 31 is wound around the outer circumference of the plurality of dielectric waveguide wires 22 , and the roll tape 31 is covered with a sheath 32 .

[0062] [6] An end structure of a dielectric waveguide cable 1, the dielectric waveguide cable 1 transmitting GHz-band electromagnetic waves using a core 2 formed of a dielectric, wherein the end component 5 and the dielectric waveguide cable 1 are arranged in such a manner that a central axis C5 of an end component 5 having a conical portion 52 and formed of a dielectric coincides with a central axis C1 of the dielectric waveguide cable 1, wherein in the dielectric waveguide cable 1, a cavity 20 extending in the cable length direction is formed in a central portion of the core 2 in a cross section perpendicular to the cable length direction, and an axial hole 50 having a reduced diameter portion 502b whose inner diameter decreases toward a front end portion of the conical portion 52 is formed in the end component 5, and the cavity 20 of the dielectric waveguide cable 1 is connected to the axial hole 50 of the end component 5.

[0063] [7] An end structure of a dielectric waveguide cable 1, wherein the dielectric waveguide cable 1 transmits electromagnetic waves in the GHz band using a core 2 formed of a dielectric, wherein the end component 5A and the dielectric waveguide cable 1 are arranged in such a manner that a central axis C5 of an end component 5A having a conical portion 52 and formed of a dielectric is aligned with a central axis C1 of the dielectric waveguide cable 1, wherein in the dielectric waveguide cable 1, a cavity 20 extending in the longitudinal direction of the cable is formed in the central portion of the core 2 in a cross section perpendicular to the longitudinal direction of the cable, and at least one linear dielectric 23 having an outer diameter smaller than an inner diameter of the cavity 20 is accommodated in the cavity 20 at an end portion of the core 2 on the side of the end component 5A.

[0064] The embodiments of the present invention have been described above, but the above embodiments do not limit the invention involved in the claims. In addition, it should be noted that the combination of features described in the embodiments is not necessarily all necessary for solving the problems of the invention.

Claims

1. A dielectric waveguide cable having a core formed of a dielectric and transmitting electromagnetic waves in the GHz frequency band through the core, characterized in that: A cavity extending along the length direction of the cable is formed in a central portion of the core in a cross section perpendicular to the length direction of the cable.

2. The dielectric waveguide cable according to claim 1, characterized in that The dielectric forming the core has a dielectric loss tangent of less than 1×10 -3 of resin.

3. The dielectric waveguide cable according to claim 2, characterized in that The ratio of the inner diameter of the cavity to the outer diameter of the cable is 20% or more and 40% or less.

4. The dielectric waveguide cable according to any one of claims 1 to 3, characterized in that The core includes a hollow dielectric waveguide tube in which the cavity is formed and a plurality of dielectric waveguide wires arranged around the dielectric waveguide tube. The plurality of dielectric waveguide wires are twisted in a spiral shape around the outer circumference of the dielectric waveguide tube.

5. The dielectric waveguide cable according to claim 4, characterized in that A compression tape is wound around the outer circumferences of the plurality of dielectric waveguide wires, and the compression tape is covered with a sheath.

6. An end structure of a dielectric waveguide cable, wherein the dielectric waveguide cable transmits electromagnetic waves in the GHz frequency band using a core formed of a dielectric, characterized in that: The terminal member and the dielectric waveguide cable are arranged so that the central axis of the terminal member having a conical portion and made of dielectric material coincides with the central axis of the dielectric waveguide cable. In the dielectric waveguide cable, a cavity extending in the cable length direction is formed in the center portion of the core in a cross section perpendicular to the cable length direction. The terminal member is provided with an axial hole having a reduced diameter portion whose inner diameter decreases toward the front end portion of the conical portion. The cavity of the dielectric waveguide cable communicates with the axial hole of the terminal member.

7. An end structure of a dielectric waveguide cable, wherein the dielectric waveguide cable transmits electromagnetic waves in the GHz frequency band using a core formed of a dielectric, characterized in that: The terminal member and the dielectric waveguide cable are arranged so that the central axis of the terminal member having a conical portion and made of dielectric material coincides with the central axis of the dielectric waveguide cable. In the dielectric waveguide cable, a cavity extending in the cable length direction is formed in the center portion of the core in a cross section perpendicular to the cable length direction. At least one linear dielectric having an outer diameter smaller than an inner diameter of the cavity is accommodated in the cavity at the end portion of the core on the terminal member side.

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