JP2017055301A - Antenna device and fixture for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device which can inhibit occurrence of failure and deterioration of the communication quality while using a coaxial cable having high flexibility, and to provide a fixture for the antenna device.SOLUTION: An antenna device 1 includes: an antenna substrate 2 in which an antenna element 2a for emitting or receiving electromagnetic waves is formed by a microstrip line 21; a radome 3 which houses the antenna substrate 2; a flexible coaxial cable 4 having a central conductor 40 connected with the microstrip line 21, an insulator 41 for covering a periphery of the central conductor 40, an external conductor 42 provided at a periphery of the insulator 41, and a sheath 43 for covering a periphery of the external conductor 42; and a fixture 5 which fixes the coaxial cable 4 to the radome 3. An introduction passage 3a into which an end part of the coaxial cable 4 is introduced is formed at the radome 3. The fixture 5 fastens the sheath 43 to hold the coaxial cable 4 and is fixed to the radome 3 inside the introduction passage 3a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an antenna device in which a coaxial cable is electrically connected to an antenna element and an antenna device fixture.

  2. Description of the Related Art Conventionally, an antenna device that includes a substrate having a plurality of radiating elements formed on the surface and a radome that accommodates the substrate and that feeds the radiating elements by a coaxial cable is used as an antenna for a base station of mobile communication, for example. Used (see, for example, Patent Document 1).

  In the antenna device described in Patent Document 1, a connector is provided at an end of a cylindrical radome that accommodates a substrate on which a radiating element is formed. The connector connects a coaxial cable made of a semi-flexible cable connected to the substrate in the radome and a corrugated copper tube type coaxial cable arranged outside the radome.

  The connector includes two guides that are electrically connected to the respective outer conductors of the two coaxial cables, and a hollow cylindrical conductive shell that is attached so that the two guides close the openings at both ends. A conductive center contact provided in the hollow portion of the conductive shell and contacting the central conductors of the two coaxial cables, and for fixing the central contact apart from the inner peripheral surface of the conductive shell And an insulator.

JP 2015-18697 A

  In the antenna device described in Patent Document 1, since the coaxial cable arranged outside the radome is a corrugated copper tube type, the flexibility is poor, and the wiring is troublesome. Further, if the coaxial cable arranged outside the radome is made highly flexible, the coaxial cable receives wind pressure load and places a burden on the connector, which easily damages the components of the connector. Furthermore, when the coaxial cable is subjected to wind pressure load, the contact between the conductive members inside the connector is likely to become unstable, and there is a possibility that the communication quality is deteriorated due to modulation distortion caused by PIM (passive intermodulation). is there.

  Therefore, an object of the present invention is to provide an antenna device and an antenna device fixture that can suppress the occurrence of a failure and the deterioration of communication quality while using a highly flexible coaxial cable.

  In order to solve the above problems, the present invention provides an antenna substrate in which an antenna element that radiates or receives electromagnetic waves is formed by a microstrip line, a housing member that houses the antenna substrate, and a connection to the microstrip line A flexible coaxial cable having a center conductor formed, an insulator covering the periphery of the center conductor, an outer conductor provided around the insulator, and a jacket covering the periphery of the outer conductor; A fixing tool for fixing the coaxial cable to the housing member, and an introduction path through which an end of the coaxial cable is introduced is formed in the housing member. Provided is an antenna device that holds a cable and is fixed to the housing member inside the introduction path.

  In order to solve the above-described problems, the present invention provides a coaxial cable connected to the antenna substrate in a housing member that houses an antenna substrate in which an antenna element that radiates or receives electromagnetic waves is formed by a microstrip line. And is fixed to the housing member inside an introduction path formed in the housing member, and a slit-like gap is formed in a part of the circumferential direction and the width of the gap is changed. A cylindrical main body having elasticity, and a shaft-shaped fastening member disposed between both ends of the main body across the gap to reduce the diameter of the main body. An antenna apparatus fixture that clamps the coaxial cable by tightening a jacket of the coaxial cable.

  According to the antenna device and the antenna device fixture according to the present invention, it is possible to suppress the occurrence of failure and the deterioration of communication quality while using a highly flexible coaxial cable.

(A) is an external view which shows the antenna apparatus which concerns on embodiment of this invention. (B) is the block diagram which showed the radome of the antenna apparatus with the virtual line (two-dot chain line), and showed the internal structure with the continuous line. It is an enlarged view which shows the periphery of the connection part of the antenna board | substrate and coaxial cable seen from the direction shown in FIG.1 (b). FIG. 3 is an enlarged view showing the periphery of the connection portion between the antenna substrate and the coaxial cable as seen from a direction different from FIG. 2. It is a perspective view which shows a fixing tool with a part of antenna board | substrate and a coaxial cable. It is the sectional view on the AA line of FIG.

[Embodiment]
Fig.1 (a) is an external view which shows the antenna apparatus 1 which concerns on embodiment of this invention. FIG. 1B is a configuration diagram in which the radome 3 of the antenna device 1 is indicated by a virtual line (two-dot chain line), and the internal configuration is indicated by a solid line. The antenna device 1 includes an antenna substrate 2, a radome 3 as a housing member that accommodates the antenna substrate 2, a coaxial cable 4 that is connected to the antenna substrate 2 inside the radome 3, and the coaxial cable 4 is fixed to the radome 3. And a fixing tool 5 (antenna device fixing tool).

  FIG. 2 is an enlarged view showing the periphery of the connection portion between the antenna substrate 2 and the coaxial cable 4 as seen from the direction shown in FIG. FIG. 3 is an enlarged view showing the periphery of the connection portion between the antenna substrate 2 and the coaxial cable 4 as seen from a direction different from FIG. 2 and 3, the radome 3 is shown in cross section. 4 is a perspective view showing the fixture 5 together with the antenna substrate 2 and a part of the coaxial cable 4, and FIG. 5 is a cross-sectional view taken along line AA of FIG.

  In the antenna substrate 2, an antenna element 2 a that radiates or receives an electromagnetic wave is formed by a microstrip line 21 on a front surface 20 a of a base material 20 made of a plate-like dielectric. A ground pattern 22 is formed on the back surface 2 b of the base material 20.

  The radome 3 includes a main body portion 30 that accommodates the antenna substrate 2 and a cylindrical portion 31 in which the fixture 5 is disposed. In the present embodiment, both the main body portion 30 and the cylindrical portion 31 are cylindrical, and the outer diameter of the main body portion 30 is formed substantially the same as the inner diameter of the cylindrical portion 31. The cylindrical portion 31 has an axial length shorter than the axial length of the main body portion 30, and is fitted to the outer periphery of one end portion of the main body portion 30. The main body 30 is made of a material such as FRP (fiber reinforced plastic) having a high electromagnetic wave transmittance. Although the material of the cylindrical part 31 does not have a restriction | limiting in particular, For example, the same thing as the main-body part 30 can be used.

  In the antenna device 1, the main body 30 is fixed to a support column (not shown) so that the cylindrical portion 31 of the radome 3 is positioned below the vertical direction. The antenna substrate 2 is fixed to the radome 3 so that the longitudinal direction thereof coincides with the central axis direction of the main body portion 30 and the cylindrical portion 31 of the radome 3.

  The coaxial cable 4 has flexibility, one end is connected to the antenna substrate 2, and the other end is connected to, for example, a transmitter or a receiver. When the other end of the coaxial cable 4 is connected to the transmitter, electromagnetic waves are radiated from the antenna element 2a of the antenna substrate 2, and when the other end of the coaxial cable 4 is connected to the receiver. The electromagnetic wave is received by the antenna element 2a of the antenna substrate 2.

  The coaxial cable 4 includes a center conductor 40 connected to the microstrip line 21, an insulator 41 covering the periphery of the center conductor 40, an external conductor 42 provided around the insulator 41, and an external conductor 42. And a sheath 43 as a jacket covering the periphery of the. The center conductor 40 is a single wire made of soft copper, for example, and is soldered to the microstrip line 21. The insulator 41 is made of, for example, a resin such as polypropylene resin, polyethylene resin, or fluorine resin (PTFE, PFA, FEP, ETFE, or the like). The outer conductor 42 is formed of a braided wire in which a copper wire or a nickel wire is woven, for example. The sheath 43 is made of an insulating material such as polyvinyl chloride or polyethylene resin.

  The radome 3 is formed with an introduction path 3a through which one end of the coaxial cable 4 is introduced. In the present embodiment, the introduction path 3 a is formed by the cylindrical portion 31. That is, the hollow part of the cylindrical part 31 becomes the introduction path 3a. Inside the cylindrical portion 31, the main body portion 30 is inserted from one end portion in the axial direction (longitudinal direction), and the fixture 5 is accommodated in the other end portion. The fixture 5 clamps the coaxial cable 4 by tightening the sheath 43 which is the outermost layer of the coaxial cable 4, and is fixed to the radome 3 inside the introduction path 3a.

  The fixture 5 is disposed between a cylindrical fixture body 50 in which a slit-like gap 50a is formed in a part of the circumferential direction, and both ends in the circumferential direction of the fixture body 50 sandwiching the gap 50a. A plurality of (four) fastening bolts 51 as shaft-like fastening members for reducing the diameter of the main body 50 are provided. The fixture main body 50 is made of, for example, a thermoplastic resin such as polyamide resin or polyacetal resin, and has elasticity that can elastically change the width of the gap 50 a in the circumferential direction of the fixture main body 50.

  The fixture main body 50 has a C-shaped section 500, a plurality of (four) ribs 501 formed on the outer periphery of the cylinder 500 and extending in the circumferential direction of the cylinder 500, and a pair with a gap 50a interposed therebetween. A plurality of pairs (four pairs) of first protrusions 502 and second protrusions 503 are integrally formed. The first protrusion 502 and the second protrusion 503 are opposed to each other through the gap 50a. The first protrusion 502 protrudes on the outer peripheral side of the cylindrical portion 500 at one side of the gap 50 a in the circumferential direction of the cylindrical portion 500, and the second protrusion 503 is a cylinder on the other side of the gap 50 a in the circumferential direction of the cylindrical portion 500. Projecting on the outer peripheral side of the portion 500. The side surface 502b on the gap 50a side of the first protrusion 502 and the side surface 503b on the gap 50a side of the second protrusion 503 are substantially parallel.

  The rib 501 is provided at a position corresponding to the first protrusion 502 and the second protrusion 503 in the axial direction of the fixture main body 50, and reinforces the cylindrical portion 500. In other words, the first protrusion 502 is continuously provided at one end of the rib 501 in the circumferential direction of the cylinder part 500, and the second protrusion 503 is continuously provided at the other end of the rib 501 in the circumferential direction of the cylinder part 500. Is provided. The outer diameter of the rib 501 is formed to be slightly smaller than the inner diameter of the cylindrical portion 31.

  As indicated by broken lines in FIG. 5, each of the plurality of first protrusions 502 is formed with a bolt insertion hole 502 a through which the shaft portion 510 of the tightening bolt 51 is inserted. Further, each of the plurality of second protrusions 503 is formed with a screw hole 503a into which a male screw formed on the shaft portion 510 of the tightening bolt 51 is screwed. The head 511 of the tightening bolt 51 is in contact with the side surface 502c of the first protrusion 502 opposite to the gap 50a.

  When the shaft portion 510 of the tightening bolt 51 is screwed into the screw hole 503a of the second protrusion 503, the inner diameter of the cylindrical portion 500 is reduced, and the distance between the side surface 502b of the first protrusion 502 and the side surface 503b of the second protrusion 503 is reduced. Becomes narrower. Thereby, the fixture 5 tightens the sheath 43 of the coaxial cable 4. The coaxial cable 4 is fixed to the fixture 5 by this tightening force, and axial movement and rotation with respect to the fixture 5 are restricted.

  As shown in FIG. 3, the cylindrical portion 500 of the fixture main body 50 is formed with an engagement hole 500 a that opens to the outer peripheral surface of the cylindrical portion 500 and has a predetermined depth in the radial direction. In the present embodiment, among the plurality of ribs 501, the introduction path 3 a is further further than the rib 501 located closest to the opening end of the introduction path 3 a (the end of the cylindrical portion 31 opposite to the main body 30 side). An engagement hole 500a is opened on the outer peripheral surface of the cylindrical portion 500 near the opening end.

  The fixing tool 5 is fixed to the cylindrical portion 31 by engaging a fixing bolt 32 inserted through the bolt hole 310 formed in the cylindrical portion 31 of the radome 3 with the engagement hole 500a. The bolt hole 310 penetrates the cylindrical portion 31 in the thickness direction, and opens to the inner surface of the introduction path 3 a (the inner peripheral surface of the cylindrical portion 31) and the outer peripheral surface of the cylindrical portion 31.

  In the present embodiment, a female screw is formed on the inner surface of the bolt hole 310, and a male screw formed on the shaft portion 320 of the fixing bolt 32 is screwed into this female screw. The shaft portion 320 of the fixing bolt 32 is screwed into the bolt hole 310 until the head portion 321 of the fixing bolt 32 contacts the outer peripheral surface of the cylindrical portion 31. As a result, the distal end portion of the shaft portion 320 of the fixing bolt 32 is fitted into the engaging hole 500 a of the fixing device 5, and the fixing device 5 is prevented from coming off and rotating with respect to the tubular portion 31.

(Operation and effect of the embodiment)
According to the embodiment described above, the following operations and effects can be obtained.

(1) Since the central conductor 40 of the coaxial cable 4 is directly connected to the microstrip line 21 of the antenna substrate 2 without using a connector, for example, it is generated due to impedance mismatching or the like at a connection portion when a connector is used. It is possible to eliminate the deterioration of VSWR (standing wave ratio) to be obtained, power loss, or modulation distortion due to PIM, and improve communication quality.

(2) The coaxial cable 4 is fixed to the radome 3 by the fixture 5 without using a connector. For this reason, the number of parts can be reduced, the risk of failure occurrence can be reduced, and the cost can be reduced. In addition, it is possible to eliminate the occurrence of problems caused by rainwater or the like entering the connector.

(3) Since the coaxial cable 4 has higher flexibility than that of, for example, a corrugated copper tube type used in a conventional antenna device, it is easy to route. Further, even if the coaxial cable 4 receives a wind pressure load, the load is absorbed by the fixture 5 that tightens the sheath 43, and no load is applied to the connection portion between the center conductor 40 and the outer conductor 42 and the antenna substrate 2. For this reason, generation | occurrence | production of contact failure can be suppressed.

(4) The fixture 5 includes a cylindrical fixture body 50 in which a slit-like gap 50a is formed in a part of the circumferential direction, and between both ends of the fixture body 50 sandwiching the gap 50a (first projection 502 and A plurality of fastening bolts 51 arranged between the second protrusions 503 and reducing the diameter of the fixing body 50, and the fixing body 50 is reduced in diameter by screwing the plurality of fastening bolts 51 to be coaxial. Tighten the cable 4. At this time, since the inner peripheral surface of the cylindrical portion 500 of the fixture main body 50 is in wide contact with the outer peripheral surface of the sheath 43, the tightening load is not locally applied, and the coaxial cable 4 can be prevented from being damaged.

(5) Since the fixing tool 5 is fixed by the fixing bolt 32 inserted through the bolt hole 310 formed in the cylindrical portion 31 of the radome 3, the fixing work is easy. Moreover, since the fixing bolt 32 engages with the engagement hole 500a formed in the cylindrical portion 500 of the fixture main body 50, the distal end portion of the shaft portion 320 is reliably prevented from coming off.

(Summary of embodiment)
Next, the technical idea grasped from the embodiment described above will be described with reference to the reference numerals in the embodiment. However, each reference numeral in the following description does not limit the constituent elements in the claims to members or the like specifically shown in the embodiment.

[1] An antenna substrate (2) in which an antenna element (2a) for radiating or receiving electromagnetic waves is formed by a microstrip line (21), a housing member (radome 3) for housing the antenna substrate (2), A center conductor (40) connected to the microstrip line (21), an insulator (41) covering the periphery of the center conductor (40), and an outer conductor (42) provided around the insulator (41) And a flexible coaxial cable (4) having a jacket (sheath 43) covering the periphery of the outer conductor (42), and a fixture for fixing the coaxial cable (4) to the housing member (3) (5), the housing member (3) is formed with an introduction path (3a) into which an end of the coaxial cable (4) is introduced, and the fixture (5) 43) While gripping table (4), fixed internally to the housing member of said introduction path (3a) (3), the antenna device (1).

[2] The fixture (5) has a cylindrical main body having a slit-like gap (50a) formed in a part of the circumferential direction and having elasticity capable of changing the width of the gap (50a). (Fixing tool main body 50) and a shaft-like tightening member (clamping bolt 51) disposed between both ends of the main body (50) sandwiching the gap (50a) to reduce the diameter of the main body (50). The antenna device (1) according to [1], including:

[3] The fixing tool (5) is fixed to the housing member (3) by a bolt (fixing bolt 32) that passes through a bolt hole (310) that opens to the inner surface of the introduction path (3a). The antenna device (1) according to [1] or [2].

[4] An antenna element (2a) that radiates or receives electromagnetic waves is connected to the antenna substrate (2) in a housing member (3) that houses an antenna substrate (2) formed by a microstrip line (21). A fixture (5) for fixing a coaxial cable (4), which is fixed to the housing member (3) inside an introduction path (3a) formed in the housing member (3), and is a part in the circumferential direction A slit-shaped gap (50a) is formed in the cylindrical body (50) having elasticity capable of changing the width of the gap (50a), and the body (50) sandwiching the gap (50a). ) And a shaft-like fastening member (51) for reducing the diameter of the main body (50). The diameter of the main body (50) reduces the diameter of the coaxial cable (4). Tighten the jacket (43) to Gripping Le (4), the antenna device fixture (5).

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  In addition, the present invention can be implemented with appropriate modifications without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the fastening bolt 51 is used as the shaft-like fastening member for reducing the diameter of the fixture main body 50 has been described. However, the present invention is not limited thereto, and for example, a rivet is used as the fastening member. May be. Alternatively, a band-type metal fitting may be used as the fastening member.

  Moreover, although the case where the one introduction path 3a was provided in the radome 3 was demonstrated in the said embodiment, you may provide not only this but the several introduction path 3a in the radome 3. FIG.

DESCRIPTION OF SYMBOLS 1 ... Antenna apparatus 2 ... Antenna board 21 ... Microstrip line 3 ... Radome (accommodating member)
32 ... Fixing bolt 4 ... Coaxial cable 40 ... Center conductor 41 ... Insulator 42 ... External conductor 43 ... Sheath 5 ... Fixing tool (fixing tool for antenna device)
50 ... Fixing body 51 ... Clamping bolt

Claims (4)

An antenna substrate in which an antenna element that radiates or receives electromagnetic waves is formed by a microstrip line;
A housing member for housing the antenna substrate;
A flexible body having a center conductor connected to the microstrip line, an insulator covering the periphery of the center conductor, an outer conductor provided around the insulator, and a jacket covering the periphery of the outer conductor Coaxial cable,
A fixture for fixing the coaxial cable to the housing member,
The housing member is formed with an introduction path through which an end of the coaxial cable is introduced,
The fixing tool is clamped to the outer cover to hold the coaxial cable, and is fixed to the housing member inside the introduction path.
Antenna device. The fixture is formed between a cylindrical main body having elasticity capable of changing a width of the gap and a gap between the both ends of the main body sandwiching the gap. A shaft-shaped fastening member that is disposed in the shaft and reduces the diameter of the main body,
The antenna device according to claim 1. The fixture is fixed to the housing member by a bolt that passes through a bolt hole that opens to the inner surface of the introduction path.
The antenna device according to claim 1 or 2. A fixing tool for fixing a coaxial cable connected to the antenna substrate to a housing member that houses an antenna substrate in which an antenna element that radiates or receives electromagnetic waves is formed by a microstrip line,
A cylindrical shape that is fixed to the housing member inside the introduction path formed in the housing member, has a slit-like gap formed in a part of the circumferential direction, and has elasticity capable of changing the width of the gap. The body of
A shaft-shaped fastening member disposed between both end portions of the main body across the gap to reduce the diameter of the main body,
The coaxial cable is clamped by tightening the outer sheath of the coaxial cable by reducing the diameter of the main body,
Fixture for antenna device.

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