Converter

Abstract

To provide a converter that can couple a derivative waveguide to a coaxial wire with low loss.SOLUTION: A converter 10 that electromagnetically couples a dielectric waveguide 3 and a coaxial line 2 comprises a shaft-shaped waveguide member 7 made of a dielectric and having a conical shaped part 71 at one end portion in an axial direction, a taper slot antenna 6 disposed to face a conical surface 71a of the conical shaped part 71, a housing 4 that accommodates the waveguide member 7 and the taper slot antenna 6, and a support member 8 that supports the waveguide member 7 with respect to the housing 4, wherein the coaxial line 2 is connected to the taper slot antenna 6 and the dielectric waveguide 3 is connected to the waveguide member 7. The support member 8 contacts a part in a circumferential direction of an outer peripheral surface 7a of the waveguide member 7 to support the waveguide member 7 with respect to the housing 4, and a gap is formed between another part in the circumferential direction of the outer peripheral surface 7a of the waveguide member 7 that is not contacted by the support member 8 and an inner surface 4a of the housing 4.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a converter for converting a transmission medium of an electromagnetic wave by electromagnetically coupling a dielectric waveguide with a coaxial line. [Background technology]

[0002] Conventionally, a transmission path for transmitting a high-frequency signal may be configured by coupling a plurality of different transmission members. For example, Patent Document 1 describes a coaxial-waveguide converter that couples a coaxial line and a waveguide. The present applicant has also proposed a dielectric waveguide described in Patent Document 2 that has excellent flexibility and is capable of transmitting electromagnetic waves in the quasi-millimeter wave band or millimeter wave band with low loss. The dielectric waveguide described in Patent Document 2 includes a core that bundles a plurality of dielectric waveguides made of a dielectric material such as a resin such as a fluororesin, and an outer jacket that covers the core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-157486 [Patent Document 2] Japanese Patent Application Publication No. 2023-169959 Summary of the Invention [Problem to be solved by the invention]

[0004] In transmission paths for transmitting high-frequency signals, it is expected that a dielectric waveguide and a coaxial line will be coupled together. Therefore, an object of the present invention is to provide a transducer that can couple a dielectric waveguide and a coaxial line with low loss. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a converter that electromagnetically couples a dielectric waveguide and a coaxial line, comprising: an axial waveguide member made of a dielectric material and having a conical portion at one axial end thereof; an antenna arranged opposite the conical surface of the conical portion; a housing that accommodates the waveguide member and the antenna; and a support member that supports the waveguide member relative to the housing, wherein the coaxial line is connected to the antenna and the dielectric waveguide is connected to the waveguide member, the support member is in contact with a portion of the circumferential surface of the waveguide member in the circumferential direction and supports the waveguide member relative to the housing, and a gap is formed between the inner surface of the housing and another portion of the circumferential surface of the waveguide member that is not in contact with the support member. [Effects of the Invention]

[0006] The converter according to the present invention makes it possible to couple the dielectric waveguide and the coaxial line with low loss. [Brief explanation of the drawings]

[0007] [Figure 1] 1A is a diagram showing a part of a transmission line including a converter according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of a coaxial line of the transmission line. [Figure 2] 1A is a perspective view showing an example of the configuration of a dielectric waveguide, and FIG. 1B is a cross-sectional view of the dielectric waveguide. [Figure 3] FIG. 2 is a six-view diagram showing the appearance of the converter. [Figure 4] (a) is a cross-sectional view taken along the axial direction of the transducer along line AA in Fig. 3. (b) is a partial cross-sectional view of one end of a dielectric waveguide connected to the transducer. (c) is a cross-sectional view of the transducer and the dielectric waveguide combined together. [Figure 5] 3A is an end view showing one axial end face of the converter, omitting the illustration of the coaxial connector. (b) is a cross-sectional view of the converter taken along line BB in FIG. 3. (c) is a cross-sectional view of the converter taken along line CC in FIG. 3. (d) is a cross-sectional view of the converter taken along line DD in FIG. 3. [Figure 6] 4A is a cross-sectional view of the converter taken along the EE line in FIG. 3, showing the inside of the housing with the second housing member omitted. 4B is an external view of the coaxial connector as seen from the direction shown in 4A. 4C is a plan view of the tapered slot antenna as seen from the direction shown in 4A. [Figure 7] 1A is a perspective view of a tapered slot antenna viewed from an oblique direction, and FIGS. 1B and 1C are explanatory diagrams showing electromagnetic waves radiated from the tapered slot antenna. [Figure 8] 10(b) is a cross-sectional view of the converter taken along line FF in FIG. [Figure 9] 1A is a graph showing the results of measuring the S parameter S21 when using the converter according to the embodiment and the converter according to the comparative example, and FIG. 1B is a graph showing the results of measuring the S parameter S11 when using the converter according to the embodiment and the converter according to the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment Mode] 1(a) is a configuration diagram showing a portion of a transmission line 1 including a converter 10 according to an embodiment of the present invention. This transmission line 1 has a coaxial line 2, a dielectric waveguide 3, and a converter 10 that electromagnetically couples the coaxial line 2 and the dielectric waveguide 3, and transmits electromagnetic waves in the GHz band. The converter 10 propagates the electromagnetic waves that have propagated through the coaxial line 2 to the dielectric waveguide 3. The transmission line 1 is particularly suitable for transmitting electromagnetic waves of 20 GHz or more and 100 GHz or less, but can also be used for transmitting electromagnetic waves of 100 GHz or more and 300 GHz or less.

[0009] 1(b) is a cross-sectional view of the coaxial line 2. The coaxial line 2 has a center conductor line 21, a dielectric 22 surrounding the center conductor line 21, an outer conductor line 23 covering the dielectric 22, and a sheath 24 covering the outer conductor line 23. The center conductor line 21 is a solid wire made of, for example, copper or a copper alloy. The outer conductor line 23 is made of, for example, a braided wire or a conductive tape. The coaxial line 2 has a connector 20 at one end, which is connected to the connector 5 of the converter 10.

[0010] Fig. 2(a) is a perspective view showing an example of the configuration of a dielectric waveguide 3. Fig. 2(b) is a cross-sectional view of the dielectric waveguide 3. Fig. 2(a) shows the end of the dielectric waveguide 3 in a stepped state. Also, in Fig. 2(a), the central axis C1 of the dielectric waveguide 3 is indicated by a dashed line.

[0011] The dielectric waveguide 3 has a core 3A, which is a waveguide made of a dielectric material, and an outer jacket 3B provided on the outer periphery of the core 3A. The core 3A is configured to have a dielectric waveguide 31 and a plurality of dielectric waveguide lines 32 arranged around the dielectric waveguide 31. The dielectric waveguide 31 is a hollow tube with a cavity 310 formed in the center. The plurality of dielectric waveguide lines 32 are twisted in a spiral shape at an angle with respect to the longitudinal direction of the dielectric waveguide 3. This configuration of the core 3A improves the flexibility of the dielectric waveguide 3.

[0012] The dielectric material constituting the core 3A has a dielectric loss tangent of 1×10 at the frequency of the electromagnetic wave transmitted by the dielectric waveguide 3. -3 The dielectric loss tangent (also referred to as tanδ, tangent delta, or tan delta) is an index value that indicates the proportion of energy that is converted into heat when an AC electric field is applied to a dielectric, and the smaller the dielectric loss tangent value, the smaller the loss. The cavity 310 of the dielectric waveguide 31 is filled with air. The dielectric loss tangent of air is lower than the dielectric loss tangent of the resin, and the formation of the cavity 310 in the center of the core 3A reduces loss. Furthermore, a portion of the electromagnetic waves transmitted by the dielectric waveguide 3 propagates on the outer surface of the dielectric waveguide 3.

[0013] Specifically, for example, any one of fluororesin, foamed fluororesin, polyethylene, foamed polyethylene, polypropylene, and foamed polypropylene can be used as the material of the dielectric waveguide 31 and the dielectric waveguide 32. The material of the dielectric waveguide 31 is desirably harder than the material of the dielectric waveguide 32 so that the dielectric waveguide 3 maintains its cylindrical shape even when bent. For example, PTFE (polytetrafluoroethylene) can be suitably used as the material of the dielectric waveguide 31, and FEP (tetrafluoroethylene-hexafluoropropylene copolymer) can be suitably used as the material of the dielectric waveguide 32.

[0014] 2(a) and 2(b), the core 3A has 30 dielectric waveguides 32 twisted in a spiral shape with an inner and outer double layer structure around one dielectric waveguide 31 arranged in the center. Of the 30 dielectric waveguides 32, 12 dielectric waveguides 32 in the inner layer are arranged so as to be in contact with the outer peripheral surface 31a of the dielectric waveguide 31, and 18 dielectric waveguides 32 in the outer layer are arranged on the outer side of the 12 dielectric waveguides 32 in the inner layer.

[0015] The jacket 3B is composed of a band-shaped pressure wrapping tape 33 wound around the outer periphery of the core 3A and a sheath 34 covering the pressure wrapping tape 33. The pressure wrapping tape 33 is spirally wound around the core 3A so that they partially overlap in the width direction. The pressure wrapping tape 33 prevents the multiple dielectric waveguides 32 from coming apart during the manufacturing process of the dielectric waveguide 3, and the sheath 34 protects the core 3A and the pressure wrapping tape 33. The sheath 34 is formed around the outer periphery of the pressure wrapping tape 33 by extrusion molding. It is sufficient that the jacket 3B is composed of at least either the pressure wrapping tape 33 or the sheath 34.

[0016] The materials of the pressure wrapping tape 33 and the sheath 34 may have a dielectric loss tangent value higher than that of the dielectric waveguide 31 and the dielectric waveguide 32, but it is desirable that they have strength higher than that of the materials of the dielectric waveguide 31 and the dielectric waveguide 32. The pressure wrapping tape 33 is made of a sealing tape made of a fluororesin such as PTFE. The sheath 34 is made of a fluororesin such as FEP, and it is preferable to use a material that is particularly excellent in abrasion resistance and tear resistance.

[0017] FIG. 3 is a six-sided view showing the appearance of the converter 10. FIG. 4(a) is a cross-sectional view along the axial direction of the converter 10 taken along line AA in FIG. 3. FIG. 4(b) is a partial cross-sectional view of one end of the dielectric waveguide 3 connected to the converter 10. FIG. 4(c) is a cross-sectional view of the converter 10 and the dielectric waveguide 3 combined together. In FIGS. 4(b) and 4(c), the appearance of the dielectric waveguide 3 is shown above the central axis C1 of the dielectric waveguide 3, and the cross section of the dielectric waveguide 3 is shown below the central axis C1. At one end of the dielectric waveguide 3, a part of the dielectric waveguide 32 is exposed from the jacket 3B, and further, the dielectric waveguide 31 protrudes from the end face 32a of the dielectric waveguide 32.

[0018] Fig. 5(a) is an end view showing one axial end face of the converter 10, omitting the illustration of the coaxial connector 5. Fig. 5(b) is a cross-sectional view of the converter 10 perpendicular to the axial direction along line BB in Fig. 3. Fig. 5(c) is a cross-sectional view of the converter 10 perpendicular to the axial direction along line CC in Fig. 3. Fig. 5(d) is a cross-sectional view of the converter 10 perpendicular to the axial direction along line DD in Fig. 3.

[0019] The converter 10 comprises a conductive housing 4, a coaxial connector 5 attached to one end of the housing 4, a tapered slot antenna 6 fixed to the housing 4, an axial waveguide member 7 made of a dielectric material arranged opposite the tapered slot antenna 6 within the housing 4, a pair of support members 8 supporting the waveguide member 7 relative to the housing 4, a pair of bolts 91, 92 for fixing the tapered slot antenna 6 to the housing 4, a pair of set screws 93, 94 for pressing the pair of support members 8 against the waveguide member 7, and positioning pins 95, 96 for positioning the waveguide member 7 and the pair of support members 8 relative to each other.

[0020] The waveguide member 7 and the support member 8 are made of a dielectric material such as fluororesin, specifically PTFE. The housing 4 is cylindrical and has a central axis C2 as its center, with a cavity 40 formed therein. Hereinafter, the direction parallel to the central axis C2 will be referred to as the axial direction. When the converter 10 is combined with the dielectric waveguide 3, the central axis C1 of the dielectric waveguide 3 and the central axis C2 of the housing 4 coincide with each other.

[0021] The housing 4 is formed by combining a first housing member 41 and a second housing member 42, and houses the tapered slot antenna 6 and the waveguide member 7. A portion of the pair of support members 8 is housed in the housing 4 in the axial direction. The first housing member 41 and the second housing member 42 are fastened together with a plurality of bolts 431 to 435. However, the first housing member 41 and the second housing member 42 may be integrated into one body to form the housing 4 as a one-piece structure. The housing 4 is made of, for example, a conductive metal, but is not limited to this, and may be made of, for example, resin whose entire surface is plated with, for example, silver or gold.

[0022] Fig. 6(a) is a cross-sectional view of the converter 10 taken along the EE line in Fig. 3, showing the inside of the housing 4 with the second housing member 42 omitted. Fig. 6(b) is an external view of the coaxial connector 5 as seen from the direction shown in Fig. 6(a). Fig. 6(c) is a plan view of the tapered slot antenna 6 as seen from the direction shown in Fig. 6(a).

[0023] The coaxial connector 5 has a center conductor 51 to which the center conductor wire 21 of the coaxial line 2 is electrically connected, and an outer conductor 52 to which the outer conductor wire 23 of the coaxial line 2 is electrically connected. The outer conductor 52 has a cylindrical threaded portion 521, a pair of mounting pieces 522, 523, and a trunk portion 524 between the threaded portion 521 and the pair of mounting pieces 522, 523. The center conductor 51 and the outer conductor 52 are insulated from each other by an insulator disposed within the trunk portion 524. The pair of mounting pieces 522, 523 are formed with threaded holes 522a, 523a, into which bolts 91, 92 are threaded, respectively.

[0024] The tapered slot antenna 6 is a planar antenna having a first element 61 and a second element 62 as antenna elements made of a flat conductor. The tapered slot antenna 6 and the waveguide 7 are aligned in the axial direction. A tapered slot 60 is formed between the first element 61 and the second element 62 in a part of the tapered slot antenna 6 on the waveguide 7 side. The distance between the first element 61 and the second element 62 in the part where the slot 60 is formed gradually increases toward the waveguide 7 side.

[0025] A feed line 63 is provided between the first element 61 and the second element 62 in a portion where the slot 60 is not formed. As shown in FIG. 6(c), the feed line 63 has a straight portion 631 extending along the axial direction between the first element 61 and the second element 62, and a connection line portion 632 connecting one end of the straight portion 631 on the slot 60 side to the first element 61. The center conductor 51 of the coaxial connector 5 is connected to the other end of the straight portion 631 by, for example, soldering. The distance between the straight portion 631 of the feed line 63 and the first element 61 is wider near the connection line portion 632.

[0026] 5(b), the first element 61, the second element 62, and the feed line 63 of the tapered slot antenna 6 are made of copper foil formed by etching on one surface 64a of a base material 64 made of a dielectric material such as FR4 (glass cloth impregnated with epoxy resin). In other words, the first element 61, the second element 62, and the feed line 63 of the tapered slot antenna 6 are formed as a wiring pattern on one surface 64a of the base material 64 of the printed circuit board 600.

[0027] The other surface 64b of the substrate 64 is in contact with the first housing member 41. The first element 61 and the second element 62 of the tapered slot antenna 6 are in contact with the mounting pieces 522, 523 of the coaxial connector 5 and the second housing 42. This places the first element 61 and the second element 62 in electrical conduction with the first housing member 41, the second housing member 42, and the outer conductor 52 of the coaxial connector 5. As shown in FIG. 5(a), a notch 410 is formed in the first housing member 41 in a portion surrounding the back side (the other surface 64b) of the feed line 63. Note that the tapered slot antenna 6 may be formed of a single layer of copper plate, omitting the substrate 64.

[0028] The printed circuit board 600 has through holes 601 and 602 through which bolts 91 and 92 are inserted. The through holes 601 and 602 penetrate the base material 64, the first element 61, and the second element 62 in the thickness direction. The bolts 91 and 92 are inserted into the bolt insertion holes 411 and 412 formed in the first housing member 41 and the through holes 601 and 602 in the printed circuit board 600, and are screwed into the screw holes 522a and 523a of the pair of mounting pieces 522 and 523 in the outer conductor 52 of the coaxial connector 5. The printed circuit board 600 is sandwiched between the pair of mounting pieces 522 and 523 and the first housing member 41, and the first element 61 and the second element 62 are in contact with the mounting pieces 522 and 523, respectively. This electrically connects the coaxial line 2 to the tapered slot antenna 6 via the coaxial connector 5.

[0029] The waveguide 7 has a conical portion 71 at one axial end and a cylindrical portion 72 that is continuous with and aligned with the conical portion 71 in the axial direction. The outer diameter of the cylindrical portion 72 is the same as the outer diameter of the end of the conical portion 71 on the cylindrical portion 72 side. The central axis C3 of the waveguide 7 coincides with the central axis C2 of the housing 4. FIGS. 4(a) and 4(c) show a conical surface 71a of a portion of the axial direction of the conical portion 71, including the tip portion 711, and a cross section of the conical portion 71 taken along the central axis C3. A central hole 70 is formed in the center of the waveguide 7, extending from an axial end face 72a of the cylindrical portion 72 opposite the conical portion 71 to the conical portion 71 along the central axis C3.

[0030] The tapered slot antenna 6 is disposed opposite a conical surface 71a, which is the outer peripheral surface of the conical portion 71. Specifically, at least a portion of the conical portion 71 is disposed in the slot 60 of the tapered slot antenna 6, and an axial portion of the conical portion 71, including a tip portion 711, is disposed between an end portion 61a of the first element 61 on the slot 60 side and an end portion 62a of the second element 62 on the slot 60 side. A first gap S1 is formed between the end portion 61a of the first element 61 on the slot 60 side and the end portion 62a of the second element 62 on the slot 60 side and the conical surface 71a of the conical portion 71.

[0031] The dielectric waveguide 3 is connected to the end of the waveguide member 7 opposite to the tapered slot antenna 6. End faces 32a of the plurality of dielectric waveguides 32 contact the axial end face 72a of the cylindrical portion 72, and a dielectric waveguide 31 is inserted into the center hole 70 of the waveguide member 7. The plurality of dielectric waveguides 32 exposed from the jacket 3B are sandwiched between a pair of support members 8.

[0032] As shown in FIG. 5(d), the pair of support members 8 contact a portion of the outer circumferential surface 7a of the waveguide 7 to support the waveguide 7 relative to the housing 4. In this embodiment, the pair of support members 8 each contact a portion of the outer circumferential surface 7a of the cylindrical portion 72 of the waveguide 7, and the cylindrical portion 72 is sandwiched between the pair of support members 8. A second gap S2 is formed between the inner surface 4a of the housing 4 and the other portion of the outer circumferential surface 7a of the waveguide 7 that is not in contact with the support members 8. The second gap S2 communicates with the first gap S1 between the first element 61 and the second element 62 and the conical portion 71 within the housing 4. The first gap S1 and the second gap S2 are filled with air, whose dielectric loss tangent is approximately zero.

[0033] The support member 8 integrally includes a curved plate portion 81 interposed between the housing 4 and the cylindrical portion 72 of the waveguide 7 and the plurality of dielectric waveguide lines 32 of the dielectric waveguide 3, and a flange portion 82 facing the axial end face 4b of the housing 4. The curved plate portion 81 is curved in an arc shape when viewed from the axial direction, and has a concave curved surface 81a facing the outer circumferential surface 7a of the waveguide 7 and a convex curved surface 81b facing the inner surface 4a of the housing 4. A pair of set screws 93, 94 contact the convex curved surfaces 81b of the one and other support members 8, and when the pair of set screws 93, 94 are tightened, the concave curved surface 81a of the curved plate portion 81 is pressed against the outer circumferential surface 7a of the cylindrical portion 72 of the waveguide 7. The axial position of the support member 8 relative to the housing 4 is determined by the flange portion 82 abutting against the axial end face 4b of the housing 4.

[0034] FIG. 7(a) is a perspective view of the tapered slot antenna 6 viewed from an oblique direction. In FIG. 7(a), an imaginary plane 6a including the tapered slot antenna 6 is shown in gray, and the radiation axis 6b of the tapered slot antenna 6 is shown by a dashed line. The radiation axis 6b is a straight line perpendicular to the arrangement direction of the first element 61 and the second element 62, and is included in the imaginary plane 6a together with the first element 61 and the second element 62. The waveguide member 7 is supported so that the central axis C3 coincides with the radiation axis 6b. The E-plane (electric field plane) of the tapered slot antenna 6 is included in the imaginary plane 6a. The H-plane (magnetic field plane) of the tapered slot antenna 6 is perpendicular to the imaginary plane 6a.

[0035] 7(b) and 7(c) are explanatory diagrams schematically showing electromagnetic waves radiated from the tapered slot antenna 6. Fig. 7(b) shows a state seen from a direction perpendicular to the imaginary plane 6a and the tapered slot antenna 6, and Fig. 7(c) shows a state seen from a direction perpendicular to the radiation axis 6b and parallel to the imaginary plane 6a. The electromagnetic waves radiated from the tapered slot antenna 6 are traveling waves that proceed toward the opening direction of the slot 60, and a portion of the waves propagates along the outer surface of the dielectric waveguide 3 via the outer peripheral surface 7a of the waveguide member 7, and another portion enters the waveguide member 7 and propagates through the cavity 310 of the dielectric waveguide 31 and the plurality of dielectric waveguides 32.

[0036] In Figure 5(d), the imaginary plane 6a is indicated by a two-dot chain line. As shown in Figure 5(d), the imaginary plane 6a does not intersect with the pair of support members 8. The pair of support members 8 sandwich the waveguide member 7 in a direction perpendicular to the imaginary plane 6a. This support structure of the waveguide member 7 makes it difficult for the support members 8 to block surface waves propagating along the outer surface 7a of the waveguide member 7. In the direction perpendicular to the imaginary plane 6a, the width W of the portion where each support member 8 contacts the waveguide member 7 is 10% or less of the outer diameter D of the cylindrical portion 72, which is the outer diameter of the waveguide member 7 at the portion where the support member 8 contacts.

[0037] FIG. 8(a) is a three-view diagram showing the configuration of a converter 10A according to a comparative example. FIG. 8(b) is a cross-sectional view of the converter 10A taken along line FF in FIG. 8(a). Like the converter 10 according to the above embodiment, the converter 10A includes a housing 4, a coaxial connector 5, a tapered slot antenna 6, and a waveguide 7. However, the shape of a support member 8A that supports the waveguide 7 relative to the housing 4 is different from that of the support member 8 according to the above embodiment. The support member 8A is made of the same dielectric material as the support member 8, and integrally includes a cylindrical portion 83 that covers the entire circumference of a portion of the cylindrical portion 72 of the waveguide 7 in the axial direction, and an annular flange portion 84 that faces the axial end face 4b of the housing 4.

[0038] 9(a) is a graph showing the results of measuring the S-parameter S21 (transmission coefficient) when the converter 10 according to the above embodiment is used and when the converter 10A according to the comparative example is used. FIG. 9(b) is a graph showing the results of measuring the S-parameter S11 (reflection coefficient) when the converter 10 according to the above embodiment is used and when the converter 10A according to the comparative example is used. In FIGS. 9(a) and 9(b), the S21 and S11 when the converter 10 is used are shown by solid lines, and the S21 and S11 when the converter 10A is used are shown by solid lines.

[0039] As shown in FIG. 9(a), when converter 10 is used, S21 is generally higher and better transmission characteristics are obtained compared to when converter 10A is used. Furthermore, as shown in FIG. 9(b), when converter 10 is used, S11 is generally lower and reflection is suppressed compared to when converter 10A is used. This proves that, due to the second gap S2 formed between the pair of support members 8 that support the waveguide member 7 in converter 10, surface waves propagating along the outer surface 7a of the waveguide member 7 are less likely to be blocked by the support members 8, and reflection at the support members 8 is suppressed, thereby improving the transmission characteristics of the transmission line 1. Within the frequency ranges shown in FIGS. 9(a) and 9(b), particularly good transmission characteristics are obtained in the 28 GHz band (27.0 GHz to 29.5 GHz).

[0040] (Actions and Effects of the Embodiments) According to the embodiment described above, the following effects (1) to (4) can be obtained.

[0041] (1) A gap is formed between a circumferential portion of the outer surface 7a of the waveguide member 7 that is not in contact with the support member 8 and the inner surface 4a of the housing 4, thereby coupling the dielectric waveguide 3 and the coaxial line 2 with low loss. (2) Since the cylindrical portion 72 of the waveguide member 7 is sandwiched between the pair of support members 8, the waveguide member 7 can be supported with high support rigidity relative to the housing 4, and a gap can be provided between the pair of support members 8. (3) The imaginary plane 6a including the tapered slot antenna 6, which is a planar antenna, does not intersect with the pair of support members 8, and the pair of support members 8 sandwich the waveguide member 7 in a direction perpendicular to the imaginary plane 6a, thereby achieving good transmission characteristics and suppressing reflection. (4) By arranging the conical portion 71 of the waveguide member 7 in the slot 60 of the tapered slot antenna 6, the distance between the first element 61 and the second element 62 and the conical surface 71a of the conical portion 71 can be shortened, and the first element 61 and the second element 62 can face the conical surface 71a of the conical portion 71 over a long distance along the axial direction, thereby reducing loss.

[0042] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiments will be described by using the reference numerals and the like in the embodiments. However, the reference numerals in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiments.

[0043] [1] A converter (10) for electromagnetically coupling a dielectric waveguide (3) and a coaxial line (2), comprising: an axial waveguide member (7) made of a dielectric material having a conical portion (71) at one end in the axial direction; an antenna (6) arranged opposite to the conical surface (71a) of the conical portion (71); a housing (4) for accommodating the waveguide member (7) and the antenna (6); and a support member (8) for supporting the waveguide member (7) relative to the housing (4), a dielectric waveguide (3) connected to the waveguide member (7); the support member (8) is in contact with a portion of the circumferential direction of the outer circumferential surface (7 a) of the waveguide member (7) to support the waveguide member (7) relative to the housing (4); and a gap (S2) is formed between the inner surface (4 a) of the housing (4) and another portion of the circumferential direction of the outer circumferential surface (7 a) of the waveguide member (7) that is not in contact with the support member (8).

[0044] [2] The converter (10) according to [1] above, wherein the waveguide member (7) has a cylindrical portion (72) that is continuous with the conical portion (71) and aligned in the axial direction, and the cylindrical portion (72) is sandwiched between a pair of the support members (8).

[0045] [3] The converter (10) according to [1] above, wherein the antenna (6) is a planar antenna having flat antenna elements (61, 62), and an imaginary plane (6a) including the antenna (6) does not intersect with the support member (8).

[0046] [4] The converter (10) according to [3] above, having a pair of support members (8), the pair of support members (8) sandwiching the waveguide member (7) in a direction perpendicular to the imaginary plane (6a).

[0047] [5] The converter (10) according to any one of [1] to [4] above, wherein the antenna (6) is a tapered slot antenna having a first element (61) and a second element (62) made of a flat conductor, a tapered slot (60) formed between the first element (61) and the second element (62), and at least a part of the conical portion (71) of the waveguide member (7) is arranged in the slot (6).

[0048] Although the embodiments of the present invention have been described above, the invention according to the claims is not limited to the above embodiments. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention.

[0049] Furthermore, the present invention can be appropriately modified and implemented without departing from the spirit and scope of the present invention. For example, in the above embodiment, the case where the central hole 70 is formed in the waveguide member 7 has been described, but the central hole 70 does not have to be formed in the waveguide member 7. In this case, a plurality of dielectric waveguide lines 32 may be arranged in the center of the dielectric waveguide 3 instead of the dielectric waveguide 31.

[0050] Furthermore, in the above embodiment, the case where the waveguide member 7 is sandwiched between a pair of support members 8 has been described, but the support structure of the waveguide member 7 is not limited to this, and various support structures can be adopted as long as a gap is formed between a part in the circumferential direction of the outer circumferential surface 7a of the waveguide member 7 that is not in contact with the support members 8 and the inner surface 4a of the housing 4. Furthermore, the support members 8 may be integrated with the waveguide member 7. [Explanation of symbols]

[0051] 1...Transmission line 10...Converter 2... Coaxial line 3... Dielectric waveguide 4...Housing 5...Coaxial connector 6...Tapered slot antenna (planar antenna) 60...Slot 61...First element 62...Second element 6a... Virtual plane 7... Waveguide member 71...conical portion 71a...conical surface 72... Cylindrical portion 7a... Outer circumferential surface 8...Support member S1...First gap S2: Second gap

Claims

1. A transducer that electromagnetically couples a dielectric waveguide and a coaxial line, a waveguide member made of a dielectric and having a conical portion at one end in the axial direction; an antenna disposed opposite to the conical surface of the conical portion; a housing that accommodates the waveguide member and the antenna; and a support member that supports the waveguide member relative to the housing, the coaxial line is connected to the antenna, and the dielectric waveguide is connected to the waveguide member; the support member is in contact with a portion of an outer circumferential surface of the waveguide member in a circumferential direction to support the waveguide member with respect to the housing, a gap is formed between another part in the circumferential direction of the outer circumferential surface of the waveguide member that is not in contact with the support member and the inner surface of the housing; Converter.

2. the waveguide member has a cylindrical portion that is continuous with the conical portion and aligned in the axial direction, The cylindrical portion is sandwiched between the pair of support members. The converter of claim 1 .

3. the antenna is a planar antenna having a flat antenna element, an imaginary plane including the antenna does not intersect with the support member; The converter of claim 1 .

4. a pair of support members are provided, and the pair of support members sandwich the waveguide member in a direction perpendicular to the imaginary plane; The converter of claim 3 .

5. the antenna is a tapered slot antenna having a first element and a second element made of a flat conductor, and a tapered slot formed between the first element and the second element, At least a portion of the conical portion of the waveguide member is disposed in the slot. A converter according to any one of claims 1 to 4.

Images