JP5461898B2 - High frequency equipment with coaxial connector - Google Patents

Description

  The present invention relates to a high-frequency device including a coaxial connector, and more particularly to an electromagnetic shield structure of a high-frequency circuit device including a high-frequency coaxial connector such as an SMA type coaxial connector.

  SMA (SUB-MINITURE Type A) type coaxial connectors are widely used as coaxial connectors for coaxial cables in the high frequency band. Materials, surface finishes, electrical / mechanical performance and environmental performance according to MIL standards (US military standards) Etc. are prescribed.

  As a related technique, in a high-frequency device provided with a coaxial connector such as an SMA type coaxial connector in a housing, there is a structure as shown in FIG. 3 as one method for preventing the influence of electromagnetic noise on the coaxial connector core wire. In the case of this housing mounting, a shield plate or rib 4 for electromagnetic shielding is provided inside the housing 2, and the connection portion between the SMA type coaxial connector core wire 16 and the coaxial cable 8 is physically surrounded by a metal so as to have a high frequency. The circuit board 3 is isolated from the electromagnetic noise source.

  As another structure, as shown in FIG. 4, a noise source, for example, a noise source on the high-frequency circuit board 3 is covered with a metal case 41 or the like to shield electromagnetic noise from reaching the SMA type coaxial connector core wire 16. It is. This structure electrically isolates the SMA type coaxial connector from electromagnetic noise.

  3 and 4, the coaxial connector 1 is fixed to the housing 2 by a fixing nut 24 arranged inside the housing 2. As shown in the drawing, the outer conductor portion 14 and the inner conductor portion 16 of the coaxial connector 1 are exposed to the outside from the fixing nut 24, and the core wire of the coaxial cable 8 is connected to the inner conductor portion 16 of the coaxial connector 1 by soldering. At the same time, the shield wire 84 of the coaxial cable 8 is electrically connected to the outer conductor 14 of the coaxial connector 1.

  In addition, a technology is known in which a coaxial connector is fixed to a housing with a fixing nut, and a shielded cable (outer conductor) of the coaxial cable is connected to a grounding (earth) metal fitting sandwiched between the nut and the housing. (Patent Document 1). In this document, a large number of bent pieces are provided in a grounding metal fitting sandwiched between a nut and a rear panel, and the bent pieces are connected to a shield wire (external conductor) of a coaxial cable. Furthermore, an attempt has been made to electromagnetically shield a large number of bent pieces arranged so as to surround a connection portion between the coaxial connector and the coaxial cable.

No. 7-35306 (Fig. 2)

  In the case of the electromagnetic shield structure using the SMA type coaxial connector in the related art, as shown in FIGS. 3 and 4, the volume of the structure indispensable for the electromagnetic shield inside the casing is increased. There was a problem that it was difficult.

  In Patent Document 1, a large number of bent pieces are regularly aligned, overlapped with the outer conductor of the coaxial cable, and sandwiched by a ferrule to be crimped, which requires a troublesome assembly work. There was a point.

  An object of the present invention is to solve the above-mentioned problem that it is difficult to reduce the size of a casing, and to provide a high-frequency device having a space-saving electromagnetic shield structure including a coaxial connector that can be easily assembled.

  The high-frequency circuit device including the coaxial connector according to the present invention is mechanically connected to a coaxial cable having a joint portion electrically connected to the central conductor portion of the coaxial connector and an outer conductor portion of the coaxial connector so as to surround the joint portion. And a first connection member that is electrically connected, and a second connection that is mechanically and electrically connected to the first connection member by including a bottom surface portion having a through hole through which at least a part of the coaxial cable passes. Member. And a grounding plate member interposed between the bottom surface portion and the first connecting member with a coaxial cable shield member interposed therebetween. The ground plate member is disposed in a direction in which the main surface thereof crosses the extending direction of the coaxial cable, and the shield member of the coaxial cable is pressed against the main surface to be electrically connected to the outer conductor portion of the coaxial connector. Yes.

  According to the present invention, it is easy to assemble, the electromagnetic shield structure in the housing can be downsized, and downsizing of the housing is realized.

It is a perspective view which shows the example which attached the space saving electromagnetic shielding structure by one Embodiment of this invention to the housing | casing of a high frequency circuit device. (A) It is decomposition | disassembly explanatory drawing which shows arrangement | positioning before the assembly of the space saving electromagnetic shielding structure shown in FIG.

(B) It is a partially expanded sectional view which expands and shows after the assembly of the space saving electromagnetic shielding structure part shown to Fig.2 (a).
It is a perspective view which shows an example of the electromagnetic shielding structure of the high frequency apparatus provided with the coaxial connector in related technology. It is a perspective view which shows the other example of the electromagnetic shielding structure of the high frequency device provided with the coaxial connector in related technology.

  A high-frequency circuit device including a coaxial connector according to the present invention includes a coaxial cable having a joint portion electrically connected to a central conductor portion of the coaxial connector, and an outer conductor portion of the coaxial connector mechanically and so as to surround the joint portion. A first connecting member that is electrically connected; and a second connecting member that is mechanically and electrically connected to the first connecting member and includes a bottom surface portion having a through hole through which at least a part of the coaxial cable passes. A grounding plate member sandwiched between the inside of the bottom surface of the second coupling member and the end surface of the first coupling member via a shield member of the coaxial cable, and the grounding plate member has its main surface Is arranged in a direction crossing the extending direction of the coaxial cable, and the shield member is pressed against the main surface of the ground plate member to be electrically connected to the outer conductor portion of the coaxial connector.

  Hereinafter, a specific configuration of the SMA type coaxial connector electromagnetic shield structure of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a perspective view showing an example in which a space-saving shield structure 46 of an SMA type coaxial connector 1 according to an embodiment of the present invention is attached to a housing 2 of a high-frequency circuit device having a high-frequency circuit board 3.

  Referring to FIG. 2 (a), which is an exploded explanatory view showing the arrangement of the space-saving shield structure 46 before assembly, and FIG. 2 (b), which is a partially enlarged sectional view showing the assembly after assembly, An embodiment of the invention will be described in detail.

  As shown in FIG. 2 (a), inside the housing 2 having the coaxial connector 1 such as an SMA type coaxial connector, a special connecting member for fixing the coaxial connector 1 to the housing 2 is used. A nut 43 is arranged. Here, the special nut is a special nut in which a male screw is provided on the outer periphery of the nut. On one end side of the coaxial cable 8 connected to the coaxial connector 1, the coaxial cable core 86 is exposed from the inner insulating coating layer 87 and penetrates the through hole 448 of the grounding plate member 44 made of a perforated metal disk or the like. doing. The shield wire 84 serving as a shield member such as a braided shield wire of the coaxial cable 8 covering the periphery of the inner insulating coating layer 87 is radially spread by the ground plate member 44 in a direction transverse to the core wire 86 of the coaxial cable 8. Yes. On the other end side of the coaxial cable 8, a so-called lid nut 45 having a lid portion at one end is disposed as a second coupling member mechanically and electrically coupled to the special nut 43.

  As shown in FIG. 2B, the coaxial connector 1 has a flange portion 12, an external conductor portion 14, and a central conductor portion 16 thereof. The central conductor portion 16 of the coaxial connector 1 inserted into the through hole 21 of the housing 2 is electrically connected to the core wire 86 of the coaxial cable 8 by soldering or the like. A male screw is provided on the outer periphery of the outer conductor portion 14 of the coaxial connector 1 and is screwed into the special nut 43. Accordingly, the casing 2 is sandwiched between the flange portion 12 of the coaxial connector 1 and the special nut 43, and the coaxial connector 1 is fixed to the casing 2. The connecting portion between the central conductor portion 16 of the coaxial connector 1 and the core wire 86 of the coaxial cable 8 is arranged so as not to protrude from the special nut 43.

  A male screw is provided on the outer periphery of the special nut 43 and the grounding plate member 44 is pressed against one end of the special nut 43 by screwing and attaching the lid nut 45, and between the grounding plate member 44 and the lid nut 45. The shield wire 84 is sandwiched between the inner surface of the lid portion. With this configuration, the shield wire 84 and the housing 2 are electrically connected, and an electromagnetic shield structure can be secured. Needless to say, the special nut 43 and the lid nut 45 are made of a conductor such as metal.

  A through hole 448 is provided at the center of the grounding plate member 44, and is arranged so as to be located around the inner insulator 87 of the coaxial cable, so that the core wire 86 of the coaxial cable and the grounding plate member 44 are arranged. Can be prevented from short-circuiting.

  According to such a configuration, the shield wires 84 are arranged radially in a direction intersecting with the extending direction of the coaxial cable, for example, in a direction orthogonal as shown in the figure, and the main surface of the ground plate member 44 is also formed of the coaxial cable. Since it is arranged in a direction intersecting with the extending direction, the component size in the extending direction of the coaxial cable can be minimized, and a space-saving electromagnetic shield structure can be realized.

  In order to realize the above configuration, the outer diameter of the ground plate member 44 is preferably larger than the inner diameter of the special nut 43 and smaller than or equal to the outer diameter of the special nut 43. Further, the inner diameter of the through hole 48 through which the coaxial cable 8 of the lid nut 45 passes is smaller than the inner diameter of the special nut 43, thereby increasing the contact area between the shield wire 84 and the grounding plate member 44 and further improving electrical conduction. It is desirable to make it.

  A through hole 448 through which at least the core wire 86 of the coaxial cable 8 passes may be provided at the center of the grounding plate member 44. Preferably, it is larger than the size through which the internal insulator 87 of the coaxial cable 8 passes. desirable. However, in order to ensure the electromagnetic shielding effect and to facilitate positioning, it is more preferable that the outer diameter of the internal insulator 87 is substantially the same. For the same reason, the inner diameter of the through hole 48 through which the coaxial cable 8 of the lid nut 45 passes is preferably about the same as the outer diameter of the external insulator 88 of the coaxial cable 8 for the shielding effect.

  The ground plate member 44 is a plate for sandwiching the shield wire 84 of the coaxial cable 8, and the shape thereof is not particularly limited as long as it is a good conductor in surface contact with the shield wire.

  The present invention does not require a rib or the like inside a casing or a metal case of a high-frequency circuit board in the related art, and can prevent the influence of internal noise by providing an electromagnetic shielding structure directly on the SMA type coaxial connector. It is possible to reduce the internal structure volume.

  Since the electromagnetic shield structure is composed of only two types of nut volumes, a comparison of the related technology shown in FIG. 3 and the volume ratio of FIG. Was realized.

  In Patent Document 1, a large number of bent pieces are regularly aligned, overlapped with the outer conductor of the coaxial cable, and sandwiched between ferrules to be crimped. Therefore, it requires troublesome assembly work and tools, Furthermore, the connection between the coaxial cable and the core wire of the coaxial connector is only surrounded by a large number of bent pieces, which is insufficient to prevent the influence of internal noise on the coaxial connector core wire. was there.

  On the other hand, in the present invention, the shield wire is easily spread radially by interposing the grounding plate member, the assembling work is facilitated and the electrical contact is secured, and the highly reliable electromagnetic shielding effect is exhibited. it can.

  Note that the present invention has actually been prototyped to demonstrate that the SMA type coaxial connector is not affected by internal noise.

  As described above, according to the present invention, in the electromagnetic shield structure that prevents the core wire of the coaxial connector from being affected by noise, there is a lid nut that is screwed onto the outside of the special nut that fixes the coaxial connector to the housing. In addition, the grounding plate member through which the coaxial cable passes and the shield member of the coaxial cable are jointly fastened and electrically connected by the special nut and the lid nut, so the electromagnetic shielding effect that prevents the influence of internal noise on the coaxial connector core wire Can be realized with a space-saving structure that is easy to assemble.

  In the present embodiment, the SMA type coaxial connector is used. However, the present invention is not limited to this, and it is needless to say that other coaxial connectors can also be used. Further, as a connection member such as a special nut or a lid nut, a connection member by fitting or fitting or a connection member by snap coupling may be employed instead of the nuts by screwing described above.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

DESCRIPTION OF SYMBOLS 1 SMA type | mold coaxial connector 12 Flange part of coaxial connector 14 Outer conductor part of coaxial connector 16 Center conductor part of coaxial connector 2 Case of high frequency circuit device 21 Through hole of case 24 Fixing nut 3 High frequency circuit board 4 Rib 41 Metal Case 43 Special nut 44 Grounding plate member 448 Grounding plate member through-hole 45 Lid nut 46 Space-saving shield structure 48 Lid nut through-hole 8 Coaxial cable 84 Coaxial cable shield wire 86 Coaxial cable core wire 87 Inside of coaxial cable Insulator 88 External insulation of coaxial cable

Claims (8)

In a high-frequency circuit device including a coaxial connector, a coaxial cable having a joint portion electrically connected to a central conductor portion of the coaxial connector, and a machine on an outer periphery of the outer conductor portion of the coaxial connector so as to surround the joint portion A first connecting member that is connected electrically and electrically, and a bottom surface portion having a through hole through which at least a part of the coaxial cable passes, and mechanically and electrically connected to the outer periphery of the first connecting member. A second connecting member; and a grounding plate member sandwiched between the bottom surface portion and the first connecting member with a shield member of the coaxial cable interposed therebetween. The main surface is arranged in a direction crossing the extending direction of the coaxial cable, and the outer diameter of the ground plate member is larger than the inner diameter of the first connecting member and smaller than the outer diameter of the first connecting member. , said seal High-frequency circuit device having a coaxial connector, characterized in that the member is conductive to the outer conductor portion electrically the coaxial connector pressed against the main surface. 2. The first connecting member is screwed to an outer periphery of an outer conductor portion of the coaxial connector, and the second connecting member is screwed to an outer periphery of the first connecting member. A high-frequency circuit device comprising the coaxial connector described in 1. The high-frequency circuit device with a coaxial connector according to claim 2 , wherein the second connecting member is a lid nut . 3. The high-frequency circuit device having a coaxial connector according to claim 2, wherein a through hole through which at least a core wire of the coaxial cable passes is provided at a center portion of the ground plate member. The high-frequency circuit device having a coaxial connector according to claim 2, wherein the shield member is radially expanded in a direction crossing the core wire of the coaxial cable. 3. The high-frequency circuit device having a coaxial connector according to claim 2, wherein an inner diameter of the through hole of the second connecting member is smaller than an inner diameter of the first connecting member. The coaxial connector has a flange portion, the casing of the high-frequency circuit device is interposed between the first connecting member and the flange portion, and the coaxial connector is fixed to the casing, and the ground plate member The high-frequency circuit device comprising the coaxial connector according to claim 2, wherein electrical continuity is formed between the housing and the casing. The coaxial connector according to claim 2, wherein the coaxial connector is an SMA type coaxial connector, the first connecting member is a special nut, and the second connecting member is a lid nut. High frequency circuit device.

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