JP5888249B2 - High frequency circuit equipment - Google Patents

Description

  The present invention relates to a high-frequency circuit device including a connection portion between a coaxial line and a microstrip line.

  Conventionally, when the center conductor of the coaxial line is arranged perpendicularly to the microstrip line and both lines are connected, the end of the center conductor of the coaxial line is prevented so that the thermal stress acts on the connection portion and the breakage does not occur. And the end of the microstrip line are connected by a metal ribbon having an extra length (see, for example, Patent Document 1). Even if a stress relief (stress removal) works due to the extra length of the metal ribbon and thermal stress acts on the connection portion between the central conductor of the coaxial line and the microstrip line, the breakage of the connection portion can be suppressed.

JP 2008-235447 A

  However, when the end portion of the central conductor of the coaxial line and the end portion of the microstrip line are connected by a metal ribbon, there is a problem that loss in electrical characteristics increases due to the parasitic inductance of the metal ribbon. In addition, since a work process for ribbon bonding the metal ribbon to the central conductor of the coaxial line and the microstrip line is required, it takes time to assemble the high-frequency circuit device, and the production price cannot be suppressed.

  The present invention has been made in order to solve the above-described problems, and when a central conductor of a coaxial line is arranged perpendicularly to a microstrip line to connect both lines, thermal stress can be applied without using a metal ribbon. The aim is to obtain a relaxed connection.

  A high frequency circuit device according to the present invention comprises a high frequency printed circuit board having a microstrip line and a through hole connected to the line, a center conductor and an outer conductor, and the center conductor is inserted into the through hole and soldered. A coaxial line in which the central conductor is disposed perpendicular to the microstrip line, and a case to which the high-frequency printed circuit board and the coaxial line are attached. The case is a space through which the central conductor passes. And the junction between the high-frequency printed circuit board and the central conductor and the periphery thereof are joined to the back surface of the high-frequency printed circuit board in a non-contact manner through the space.

  According to the present invention, it is possible to relieve the thermal stress generated in the solder joint portion between the microstrip line and the central conductor of the coaxial connector and the high-frequency printed circuit board.

1 is a diagram showing a configuration of a high-frequency circuit device according to Embodiment 1. FIG. 2 is a partial enlarged cross-sectional view of a coaxial connector of the high-frequency circuit device according to Embodiment 1. FIG.

Embodiment 1 FIG.
1A and 1B are diagrams showing a configuration of a high-frequency circuit device according to Embodiment 1 of the present invention, in which FIG. 1A is a top view of the high-frequency circuit device, and FIG. 1B is an XX cross-sectional view of the high-frequency circuit device. FIG. 2 is an enlarged view of part A of the high-frequency circuit device. 1, the high-frequency circuit device according to the first embodiment includes a high-frequency printed circuit board 1, a coaxial connector 3 having a coaxial line, a high-frequency circuit 20, and a metal container (hereinafter referred to as a case) 7 made of metal. . The case 7 has a concave cavity 30 formed in the upper part. The high-frequency printed circuit board 1 and the high-frequency circuit 20 are housed in the cavity 30 above the case 7, and are held and fixed using screws or an adhesive. A lower portion of the case 7 is formed with a protruding portion 19 that protrudes downward and is provided with a hole near the right side surface of FIG. The coaxial connector 3 is disposed inside the hole of the protruding portion 19 at the bottom of the case 7. The upper end portion of the coaxial connector 3 is connected to the end portion of the high-frequency printed circuit board 1. The case 7 may be a metal, a resin member whose surface is covered with a conductor film, or a multilayer ceramic with a ground conductor attached to the surface.

  The high frequency circuit 20 includes an oscillator, an amplifier, a frequency converter (mixer), an attenuator, a phase shifter, a filter circuit, and the like formed or mounted on a compound semiconductor substrate or a ceramic substrate. The high-frequency circuit 20 performs local signal oscillation, signal amplification, frequency conversion, signal attenuation, phase shift (phase shift), signal passband for RF (Radio Frequency) signals (hereinafter referred to as high frequency signals) such as microwaves and millimeter wave bands. Perform signal processing such as restriction.

  The high frequency printed circuit board 1 is composed of a high dielectric constant high frequency substrate in which PTFE (fluorine resin) is reinforced with a glass material, for example, and the high frequency substrate sandwiches one dielectric layer or inner layer conductor. It consists of dielectric layers stacked in multiple layers. The high-frequency printed circuit board 1 has a strip conductor 25 formed on the top surface and a ground conductor 26 formed on the back surface. The strip conductor 25 and the ground conductor 26 together with the dielectric layer between the strip conductor 25 and the ground conductor 26 in the high-frequency printed circuit board 1 constitute a microstrip line.

  The high frequency printed circuit board 1 transmits a high frequency signal processed by the high frequency circuit 20 to the coaxial connector 3 or transmits a high frequency signal input from the coaxial connector 3 to the high frequency circuit 20. The connection portion between the high-frequency printed circuit board 1 and the coaxial connector 3 constitutes a vertical converter that converts the signal transmission direction of the coaxial connector 3 and the microstrip line into a vertical direction. In addition, space saving of a circuit mounting area (footprint) can be achieved by using the coaxial connector 3 and the vertical converter of a microstrip line in the high frequency circuit device.

  1 and 2, the coaxial connector 3 includes a center conductor 4, an outer conductor 15, and an insulator 16 to constitute a coaxial line. The center conductor 4 is made of a wire material obtained by extending a conductive metal having a circular cross section into an elongated shape. The outer conductor 15 forms a circular tube shape having an inner diameter larger than that of the central conductor 4 and is made of a conductive metal. A male screw 10 is formed on the outer periphery of the outer conductor 15, and a small-diameter portion where the male screw 10 is not formed is provided on the top. The center conductor 4 is disposed on the inner side of the inner periphery of the outer conductor 15. The insulator 16 is made of an insulating material such as a fluororesin or glass material having a cylindrical shape, and is filled between the inner periphery of the outer conductor 15 and the outer periphery of the center conductor 4 without a gap. The upper end portion of the center conductor 4 is disposed so as to protrude upward from the upper end portion of the outer conductor 15. The upper end portion of the insulator 16 is flush with the upper end portion of the outer conductor 15. In the lower part of the coaxial connector 3, a receptacle (receptor) 17 constituting a male coaxial connector is formed. A lower portion of the center conductor 4 protrudes inside the receptacle 17. The receptacle 17 has a structure in which a separate male coaxial connector is fitted. The center conductor 4 inside the receptacle 17 is fitted into a split sleeve provided inside the male coaxial connector. The split sleeve of the male coaxial connector forms a central conductor having an outer conductor formed around it.

  In the protruding portion 19 of the case 7, a stress relief space 11, a through hole 21, an impedance matching space 13, and a screw hole 27 are sequentially formed around the center conductor 4 of the coaxial connector 3. The stress relief space 11, the through hole 21, the impedance matching space 13, and the screw hole 27 are arranged on the coaxial line and communicate with each other. The inner peripheral diameters of the stress relief space 11 and the impedance matching space 13 are larger than the inner peripheral diameter of the through hole 21. The inner diameters of the stress relief space 11 and the impedance matching space 13 are approximately the same. The outer conductor 15 of the coaxial connector 3 is held and fixed to the case 7 with the male screw 10 engaging with a screw hole 27 which is a female screw.

  The high frequency printed circuit board 1 has a through hole 2 penetrating the top and bottom of the substrate at the end. The through hole 2 has a conductor film formed on the inner periphery. The through hole 2 is formed with a conductor film constituting the open stub 2c at the upper edge of the hole and a donut-shaped conductor film 2b at the lower edge. The conductor film of the through hole 2 is connected to the strip conductor 25 of the microstrip line. The upper end portion of the center conductor 4 of the coaxial connector 3 is inserted into the through hole 2 of the high-frequency printed circuit board 1 and is disposed on the center axis of the through hole 2 so as not to contact the through hole 2. In this state, the upper end portion of the center conductor 4 is soldered to the conductor film of the through hole 2 to form a solder joint portion 5. The central conductor 4 of the coaxial connector 3 is disposed in a non-contact manner on the center axis of the holes of the stress relief space 11 and the impedance matching space 13. In FIG. 2, the hole diameter of the through hole 2 is approximately the same as the hole diameter of the through hole 21, but is not limited thereto.

  The ground conductor 26 on the back surface of the high-frequency printed circuit board 1 is bonded to the bottom surface of the cavity 30 of the case 7 using the conductive substrate bonding material 6 as a bonding medium. The substrate bonding material 6 is made of a conductive adhesive, solder, or the like. Around the through hole 2 on the back surface of the high-frequency printed circuit board 1, a non-joint portion 12 is formed in which the ground conductor 26 is removed and the surface of the insulator is exposed. A part of the high-frequency printed circuit board 1 including the non-joining portion 12 in contact with the stress relief space 11 constitutes a solder non-joining portion 32.

The high-frequency circuit device according to Embodiment 1 is configured as described above and operates as follows.
The coaxial connector 3 and the high-frequency printed circuit board 1 are joined to the case 7, and the central conductor 4 and the through hole 2 of the high-frequency printed circuit board 1 are joined rigidly at the solder joint 5. For this reason, when a thermal shock is applied due to a temperature change in the surrounding environment, the solder joint portion 5 that connects the center conductor 4 and the through hole 2 due to the difference in thermal expansion coefficient between the center conductor 4 and the solder joint portion 5. Thermal stress is generated.

However, since the gap and the solder non-joining portion 32 are provided in the stress relief space 11 below the through hole 2, the thermal stress acting on the high-frequency printed circuit board 1 due to the expansion and contraction of the central conductor 5 causes the solder non-joining portion 32 to bend. As a result, the thermal stress applied to the solder joint 5 is absorbed. For example, when an iron nickel cobalt (Fe / Ni / Co) alloy (for example, thermal expansion coefficient 4.7 × 10 ⁻⁶ / ° C.) is used as the center conductor 4, the solder joint portion 5 (for example, thermal expansion coefficient 24.7 × 10 ^−6). Thermal stress is applied due to the difference in thermal expansion coefficient from / ° C. At this time, the thermal contraction of the solder joint portion 5 increases, but the PTFE substrate having a thermal expansion coefficient close to that of the solder joint portion 5 as the high-frequency printed circuit board 1 (for example, the thermal expansion coefficient in the in-plane direction is 16 × 10 ⁻⁶ / ° C. By using an RT / Duroid board (Rogers Corporation product, Duroid is a registered trademark of Rogers Corporation) having a thermal expansion coefficient of 24 × 10 ⁻⁶ / ° C. in the thickness direction, the non-joint portion 32 of the high-frequency printed board can be obtained. The heat shrinks in the same manner as the solder and acts as a stress relief for the solder joint 5.

  Further, the male screw 10 is formed on the outer conductor 15 of the coaxial connector 3, and the male screw 10 engages with the screw hole 27 (female screw) of the case 7 and is screw-coupled, thereby joining such as an adhesive or solder. Even if the material 8 is not poured, the coaxial connector 3 is securely fixed to the case 7. Thus, since it is not necessary to pour the bonding material 8 between the coaxial connector 3 and the case 7, even if a gap is provided in the contact portion between the outer conductor 15 and the case 7, the bonding material 8 penetrates and leaks into the gap ( Therefore, the impedance matching space 13 having a desired size can be reliably formed at the contact portion between the end face of the outer conductor 15 and the bottom of the screw hole 27 of the case 7. The impedance matching space 13 can be freely formed in the case 7 by machining. Thus, since the electrical path can be freely adjusted by providing the impedance matching space 13, the output characteristics of the high-frequency circuit device can be improved by combining the input impedance and the output impedance.

  As described above, the high-frequency circuit device according to the first embodiment includes the high-frequency printed circuit board 1 in which the microstrip line and the through hole 2 connected to the line are formed, the center conductor 4 and the outer conductor 7, and the center conductor 4 is inserted into the through-hole 2 and soldered, and a coaxial line in which the central conductor 4 is arranged perpendicular to the microstrip line, and a case 7 to which the high-frequency printed circuit board 1 and the coaxial line are attached, The case 7 has a stress relief space 11 through which the center conductor 4 penetrates, and the high frequency printed circuit board 1 and the solder joint 5 of the center conductor 4 and the periphery of the solder joint 5 are contactless by the stress relief space 11. Bonded to the back surface of the high-frequency printed circuit board 1. Thus, in the vertical converter between the coaxial connector 3 and the microstrip line, a stress relief space 11 is formed between the back surface of the high frequency printed circuit board 1 and the bonding surface of the case 7, and the solder joint portion 5 and its periphery in the high frequency printed circuit board 1. By forming the solder non-joining portion 32 in (surrounding), the solder non-joining portion 32 has a structure that relieves the thermal stress of the solder joint portion 5 in the central conductor 4 of the coaxial connector 3 (stress relief). It is a feature.

  With such a configuration, in the high frequency circuit device, thermal stress generated in the solder joint portion 5 of the central conductor 4 of the microstrip line and the coaxial connector 3 and the high frequency printed board 1 can be alleviated.

  In the high-frequency circuit device according to the first embodiment, in the vertical converter for vertically converting the coaxial connector 3 and the microstrip line, the male screw 10 is provided on the outer conductor 15 of the coaxial connector 3 and the screw hole of the case 7 is screwed. 27, and the impedance matching space 13 is provided at the contact portion between the end face of the outer conductor 15 and the bottom of the screw hole 27 of the case 7, thereby providing impedance matching between the coaxial connector 3 and the microstrip line. It is characterized by that.

  With this configuration, the outer conductor 15 of the coaxial connector 3 is engaged with the screw hole 27 of the case 7 by screw coupling, and the contact portion between the end of the outer conductor 15 and the bottom of the screw hole 27 of the case 7 is engaged. By forming the impedance matching space 13 in the impedance matching between the coaxial connector 3 and the microstrip line can be easily achieved.

  DESCRIPTION OF SYMBOLS 1 High frequency printed circuit board, 2 Through hole, 3 Coaxial connector, 4 Center conductor, 5 Solder joint, 6 Board joining material, 7 Case, 8 Joining material, 10 Male screw, 11 Stress relief space, 13 Impedance matching space, 15 Outside Conductor, 16 insulator, 19 protrusion, 20 high-frequency circuit, 21 through-hole, 25 strip conductor, 26 ground conductor, 27 screw hole, 32 solder non-joining part.

Claims (2)

A high-frequency printed circuit board on which a microstrip line and a through hole connected to the line are formed;
A coaxial conductor composed of a central conductor and an outer conductor, the central conductor inserted into a through hole of the high-frequency printed circuit board and soldered, and the central conductor disposed perpendicular to the microstrip line;
A case to which the outer conductor of the high-frequency printed circuit board and the coaxial line is attached;
With
The case has a space through which the central conductor penetrates, and the through hole of the high-frequency printed circuit board , the solder joint portion of the central conductor and the periphery thereof are joined to the back surface of the high-frequency printed circuit board in a non-contact manner through the space. High frequency circuit device.   The high-frequency circuit device according to claim 1, wherein the outer conductor of the coaxial line is provided with a screw, and is engaged with the case by screw connection.

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