JP2001185254A - Board for microwave and connection mechanism of connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To output a microwave signal to the outside of desired level by suppressing the discontinuity of GND of a microwave signal, generated at the transmission path constructed with a board housed in a housing and a connector, to restrain to a state where it will not influence the signal. SOLUTION: A two-layered board 30 is housed in a body of equipment 10a, and mounted on a board fixing part 19 and fixed to the body of equipment 10a by a screw 22. At this time, the board 30 is in a state of being lifted from a bottom board 11. A connector 120 is inserted into the connector insertion hole 16 from a side 12a at the outer surface of the body of equipment 10a, and the body of equipment 10a is fixed by a screw 125. A GND part 31 at the back side of the board 30 and an outward guide body 123 are soldered (soldering part 23 of the figure (b)).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection mechanism between a microwave circuit board and a connector for suppressing attenuation of a microwave signal due to mismatch of a microwave signal transmission line in connection between a printed wiring board and a connector.

[0002]

2. Description of the Related Art Currently, in communication equipment and other devices,
Printed wiring boards are used because of their small size, high-density mounting, and ease of wiring. On this printed wiring board,
A passive element, an active element, and the like are mounted, and each is generally connected by a microstrip line.

When handling high-frequency signals that need to be designed as distributed constant circuits, such as microwaves, on a printed wiring board, microstrip lines are mainly used.
FIG. 9 is a principle diagram showing microwave propagation on a microstrip line. Microstrip line is conductor 1
01, the conductor 103 is configured to sandwich the dielectric 102, and the conductor 103 is grounded. When the microwave propagates through the microstrip line, an electric field and a magnetic field are generated as shown in FIG. 9 and propagate in a direction perpendicular to the electric field and the magnetic field, that is, along the conductor direction (parallel to the conductor).

A microwave signal amplified and modulated on a printed wiring board composed of a microstrip line, a passive element, and an active element is generally output to the outside by a connector having a coaxial line structure. The connector is
The outer conductor of the connector and the GND portion of the board (conductor 103 in FIG. 9), and the center conductor of the connector and the conductor 1 of FIG.
01, the microwave signal is transmitted.

[0005] Further, the printed wiring board is housed in a housing due to signal leakage, radiation, or a problem with board strength. The housing generally has the attribute of GND, and aluminum or the like is generally used in terms of ease of processing, cost, and strength.

A conventional connection example between a board housed in a housing and a connector will be described below.

<First Conventional Example> First, a description will be given of a first conventional example in which a two-layer board is housed in a housing and connected to a connector. FIG. 10 is a perspective view showing the configuration of this housing. The housing 110 of FIG. 10 is an aluminum box-shaped housing, in which a substrate is housed inside, and a screw hole 119 for fixing the substrate to the bottom plate is provided. The housing 110 has a hole 116 in which a connector can be mounted, and a screw hole 117 for fixing the connector to the housing 110.

Next, examples of connectors having a coaxial line structure are shown in FIGS. 11 (a), 11 (b) and 11 (c). FIG. 11 (b),
(C) is a diagram viewed from arrows A and B in FIG. 11 (a), respectively. As shown in FIGS. 11A, 11B, and 11C, the connector 120 includes a central conductor 121 and a dielectric 12.
2. It comprises an outer conductor 123 (123a to 123c), and a dielectric 122 is filled between the center conductor 121 and the outer conductor 123 to form a coaxial line. In addition, for convenience of description below, as shown in FIG. 11A, the outer conductor 123 is referred to as outer conductors 123a, 123b, and 123c from the left. The outer conductors 123a and 123c are cylindrical and have outer conductors 123b.
Has a rectangular plate shape, and has fixing screw holes 124 formed near four corners.

The housing 110 shown in FIG. 10 and the connector 1 shown in FIG.
FIG. 12 shows an example of a connection between a board and a connector when using the No. 20 connector.
(A) and (b) show. FIG. 12A is a cross-sectional view of the connector connection mechanism, and FIG. 12B is a plan view thereof.
It is assumed that the substrate 130 is a two-layer substrate, and a passive element and an active element are mounted on the conductor 131 on the upper side when the substrate 130 is housed in the housing 110 and connected by a microstrip line. When the substrate 130 is housed in the housing 110, the conductor 132 on the lower side is a ground conductor (GND plane).

First, in the board storage space of the housing 110,
Stored until the substrate 130 contacts the bottom surface of the housing 110,
It is fixed to the housing 110 with screws 118. Next, the housing 11
0 in the connector mounting hole 116,
0 outer conductor 123c is attached from the outside of the housing 110,
It is fixed to the housing 110 with screws 125.

At this time, as shown in FIG. 12B, the center conductor 121 is brought into contact with the connection conductor 133 of the center conductor 121 formed of a microstrip line on the substrate 130 and soldered. .

As shown in FIGS. 12A and 12B, the GND of the board 130 and the GND of the connector 120 are generally connected as follows. First, the GND between the substrate 130 and the housing 110 is the screw 118 of FIG.
The connection is established by contact between the ND section 132 and the housing 110.
The GND between the housing 110 and the connector 120 is the screw 125 of FIG.
Connection is made by contact with 23b. Therefore, GND between the board 130 and the connector 120 is the screw 118, the screw 12
5. The connection is made via the housing 110 by the contact between the GND portion 132 of the substrate 130 and the housing 110, and the contact between the outer conductor 123b (GND portion) of the connector 120 and the housing 110.

<Second Conventional Example> Next, as a second conventional example, an example of connection between a printed wiring board having three or more layers and a connector will be described. FIGS. 13A and 13B are configuration diagrams illustrating a housing used in the second conventional example, in which FIG. 13A is a cross-sectional view of a board accommodating portion of the housing, and FIG. 13B is a plan view of the housing. The housing 140 shown in FIG. 13A has a box shape made of sheet metal. At a board storage position of a side plate, the board is bent inward to protrude to form a board storage section 141, and a board is placed thereon. Thus, the substrate can be stored. However, the housing 140 is
As shown in FIG. 13A, a connector connection hole 146 and a screw hole 147 are formed in the connector connection surface.

The multi-layer substrate 150 having three or more layers housed in the housing 140 has 2n (n =
2, 3, 4 ...) layer structure. As shown in FIG. 14, the inner conductor is designed and processed to be smaller than the conductor of the layer that is in contact with air (hereinafter referred to as the outer conductor) so that each layer of the multilayer substrate 150 does not short-circuit. Therefore, the outer dimension difference between the outer conductor 151 and the inner conductor 152 is m.

In each layer, the same potential portion, particularly GND, is connected by a through hole. Typically,
The two outer layer conductors formed on the front surface / back surface of the multilayer substrate are
It is generally referred to as a component side or a solder side, and which of them is referred to as a component side or a solder side is generally arbitrary. Here, when the substrate 150 is stored in the housing 140, the conductor surface on the upper side is called a component surface, and the conductor surface on the lower side is called a solder surface. In the multilayer substrate 150, the inner layer conductors are arranged in the first order from the component side.
It will be referred to as an inner layer or a second inner layer. In the 2n layer board, the first layer is the component side, the 2n layer is the solder side,
Others are inner layers.

The multilayer board 15 is connected via the casing 140 shown in FIG.
15 and 16 show examples of connection between connector 0 and connector 120.
(A) and (b) show. As shown in FIG. 15, the multilayer substrate 150 is a four-layer substrate. The four-layer board 150 includes a component surface layer, a first inner layer, a second inner layer, and a solder surface layer from the upper layer, and the component surface layer and the first inner layer constitute a microstrip line. Here, the first inner layer is connected to a ground conductor (FIG. 1).
5), and as shown in FIG.
D and the first inner layer are connected via a through hole 153. The propagation of the microwave signal on the multilayer substrate 150 is the same as that shown in FIG. The microwave signal on the microstrip line constituted by the component surface layer and the first inner layer is output to the outside by the coaxial connector 120.

As shown in FIG. 15, the four-layer substrate 150 is housed in the
The GND portion of the outer conductor 50 and the housing 140 are soldered (soldering portion 161 in FIG. 15). 12, the connector 120 is mounted on the connector mounting hole 146 formed in the housing 140 from the outside of the housing 140, and is fixed to the housing 140 with the connector mounting screw 125.

In this way, as shown in FIGS. 16A and 16B, the board 150 and the connector 120 are connected via the housing 140. The housing 140 and the GND portion (outer conductor 123) of the connector 120 are connected by contact of the connector mounting screw 125 or the housing 140 and the GND portion (outer conductor 123b) of the connector 120. Further, the first inner layer serving as the GND portion of the microstrip line and the housing 1
Reference numeral 40 denotes a connection between the GND portion of the component surface layer and the solder surface layer and the soldering portion 161 of the GND portion of the component surface layer and the solder surface layer via the through hole 22. Therefore, the connection between the first inner layer, which is the GND portion of the microstrip line, and the outer conductor 123 of the connector is made through the through hole 153 and the multilayer substrate 1.
The connection is made by soldering the connector 50 to the housing 140 or by contacting the connector mounting screw 125 or the housing 140 with the connector 120.

[0019]

In the first conventional example, that is, in the connection structure of the two-layer board 130 and the connector 120 shown in FIG. 12, a microstrip line in which a high-frequency signal such as a microwave signal is arranged on the board 130 is used. The following problem occurs when the data is output to the outside through the connector 120 from the external device. That is, the position and number of the screw 118, the substrate 1
The level of the microwave signal to be output differs depending on the state of contact between the GND plane 30 and the housing 110. Substrate 130
In the contact between the GND plane of the housing 110 and the
The housing 110 cannot be brought into contact with the housing 110 without any gap because it is a hard material. Therefore, the GND signal is
And the state of the gap affects the impedance matching between the microstrip line and the connector 120 as a coaxial line, and a desired microwave signal may not be obtained.

As one of the countermeasures, the number of screws for fixing the substrate 130 to the housing 110 has been increased, or a design has been made in consideration of impedance matching of screw mounting positions and intervals. Thus, by increasing the connection amount between the housing 110 and the substrate 130 as much as possible,
The method of stable connection of D has been taken. In general, in order to stably connect one surface of the GND to another, the interval between the screws 118 is set to λ / 8n (λ: wavelength, n = 1, 2,
…) However, in the case of high-density mounting with respect to the board area, the number of screws that can be used is limited, and a desired screw mounting position or interval may not be obtained.

As another measure, the GND of the substrate 130 is
Soldering the case 110 to the GND land formed on the surface via the surface and the through hole. However, since the aluminum housing 110 has high heat dissipation, it needs to be soldered at high heat. In the case of soldering at high heat, the maximum heat resistance standard is degraded by the material of the mounted component, and when the temperature exceeds the heat resistance temperature, characteristic deterioration or destruction occurs. Generally, the aluminum casing 110 and the substrate 13
0, or soldering to the connector 120 requires high heat higher than the maximum heat resistance standard.
It is difficult to connect the GND section 0, the housing 110, and the GND section of the connector 120.

The second conventional example, that is, the connection structure between the four-layer substrate 150 and the connector 120 shown in FIGS. 15 and 16 also has the following problem. When a high frequency such as a microwave is output from a microstrip line arranged on a substrate to the outside via a connector, in the above-described GND connection, between the first inner layer of the multilayer substrate 150 and the outer conductor 123 of the connector 120. In this case, the microwave signal level is attenuated. That is, the first and second inner layers are smaller in outer shape than the component surface due to problems in manufacturing the multilayer substrate. Accordingly, as shown in FIG. 14, a portion m where the conductor of the inner layer which is the ground conductor is not present with respect to the conductor on the component surface of the microstrip line. Inner layer conductors are connected. Therefore, when the distance between the GND portion of the connector 120 and the through hole 153 is equal to or longer than λ / 4 (λ: wavelength), the microwave signal is L-shaped, and the microwave signal level is attenuated.

As a countermeasure for suppressing the attenuation, a method of arranging the through hole 153 so that the position of the through hole 153 is λ / 4 or less with respect to the connector GND portion is considered. However, FIG.
As shown in (b), the wavelength λ is very short at a high frequency, and if the position of the through hole 153 is arranged at λ / 4 or less with respect to the connector GND portion, the GND portion formed on the component surface by opening the through hole 153 is formed. Is closer to the connection conductor 15 of the connector center conductor 9 (FIG. 16B).
Length p). Generally, in order not to affect the microwave transmission, p is the connection conductor 15 of the connector 120.
Although it is required to be five times or more than one, the through hole 153 is required.
Is less than or equal to λ / 4 with respect to the connector GND portion, this cannot be satisfied. Therefore, a desired signal level of the microwave signal level output from the connector 120 may not be obtained in some cases.

As described above, when a high frequency such as a microwave is output from the board to the outside via the connector, the ground conductor of the microstrip line on the board and the G of the connector are output.
The connection of the ND section becomes mismatched, and the GND section becomes discontinuous in the transmission path of the microwave signal, which sometimes makes it difficult to output the microwave signal to a desired level to the outside.

An object of the present invention is to reduce the discontinuity of GND in a microwave signal transmission path composed of a board and a connector housed in a housing without affecting the signal in consideration of the above problem. An object of the present invention is to provide a connection mechanism between a microwave substrate and a connector, which can suppress and output a microwave signal of a desired level to the outside.

[0026]

According to the present invention, there is provided a substrate having a microstrip line accommodated in a box-shaped housing comprising a bottom plate and a side plate standing upright, a center conductor, an outer conductor, and a dielectric between them. And a connector for connecting a connector having a structure of a coaxial line filled with a microwave substrate and the connector via the housing. The housing is provided with a board fixing portion for floating and fixing the board from the bottom plate, and a connector mounting hole formed to penetrate the side plate and having a size larger on the inner side than on the outer side of the side plate. The substrate housed in a housing is fixed to the substrate fixing portion, the connector is mounted in the connector mounting hole, and an outer conductor of the connector is connected to GND of the substrate by soldering. Things.

A counterbore may be formed inside the side plate where the connector mounting hole is formed and around the hole, and the size of the connector mounting hole gradually increases as going from the outside to the inside of the side plate. May be larger.

Further, the substrate may have a multilayer structure, in which the GND conductor in the inner layer is exposed to the outside, and the exposed portion and the outer conductor of the connector may be soldered.

In the present invention, since the GND portion of the board and the connector housed in the housing is soldered by having the above-described substrate and housing mechanism, the GND in the transmission path of the microwave signal is provided. The microwave signal at a desired level can be output to the outside while the discontinuity of the signal is not affected.

This reduces the heat radiation as much as possible by reducing the contact portion between the board and the connector, which is provided between the board and the connector, or between the housing and the connector.
In this way, the amount of heat required for soldering can be reduced, and soldering can be performed with less influence on the mounted components.

Further, the conductor serving as the GND portion of the microstrip line in the inner layer of the multilayer substrate is exposed to the outside, and the exposed portion and the outer conductor of the connector are exposed. It can be attached. Thus, it is possible to directly solder to the GND portion of the inner layer of the substrate without through the through hole, and it is possible to reduce the amount of signal attenuation.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> First, a first embodiment of a connection mechanism between a microwave substrate and a connector according to the present invention will be described. This connection mechanism accommodates a two-layer board composed of microstrip lines in a housing,
This is a mechanism for connecting a connector having a coaxial line to the board via a housing. When a microwave signal modulated and amplified on the two-layer board is output to the outside by a connector, the microwave signal is connected to the microstrip line on the board, which is a microwave transmission path. This is to minimize the mismatch between the GND connection between the board and the connector.

First, FIG. 1 shows a perspective view of the housing of the present embodiment. As shown in FIG. 1, the housing 10 has a box-like shape, a rectangular bottom plate 11, and side plates 1 erected vertically on four sides thereof.
2, 13, 14, and 15. A hole for installing a connector 120 (the same structure as the conventional example) is formed through the side plate 12, and a hole for installing the connector 120 is a connector mounting hole to which the connector 120 of FIG. 11 can be mounted. 16 and a screw hole 17 for fixing the connector 120 and the housing 10 of FIG. The outer surface of the side plate 12 is referred to as a side surface 12a, and the inner surface is referred to as a side surface 12b. Similarly, the outer surface of the side plate 13 is a side surface 13a, the inner surface is a side surface 13b, the outer surface of the side plate 14 is a side surface 14a, the inner surface is a side surface 14b, the outer surface of the side plate 15 is a side surface 15a, and an inner surface. Is the side surface 15b.

At four corners inside the bottom plate 11 of the housing 10, there are formed substrate fixing portions 18 each having a rectangular shape. At the center of the upper surface of the substrate fixing portion 18, a screw hole 19 for fixing the substrate is provided. The substrate is placed on the substrate fixing portion 18, floats from the bottom plate 11, and is fixed to the substrate fixing screw holes 19 with screws.

The housing 10 has the above structure.
Some examples are further considered depending on the shape of the side plate 12 in which the connector mounting holes 16 are formed. FIG. 2 is an enlarged view showing an example of a housing and a substrate housed therein. This housing 1
0a is a connector mounting hole 1 in the inner side surface 12b of the side plate 12.
The counterbore 21 is formed so that 6 is enlarged. FIG.
As shown in (a), the remaining thickness of the counterbore 21 portion is L1, the length of the outer conductor 123c of the connector 120 is L3, and the side plate 12 is
Let L2 be the plate thickness of L3.
= L2, L1 <L3.

The substrate 30 shown in FIG. 2 is a two-layer substrate and has the same configuration as the substrate 130 described in the conventional example. That is, in the two-layer board 30, components are mounted on the upper conductor when housed in the housing, and are connected to each other by the microstrip line in the microwave transmission path. When the substrate is housed in the housing, the lower conductor is a solid GND surface, which is a GND portion of the microstrip line.

Next, the process of connecting the connector 120 to the board 30 will be described. The two-layer substrate 30 is housed in the housing 10a,
The substrate 30 is placed on the substrate fixing portion 19 and fixed to the housing 10a with screws 22. At this time, the substrate 30 is floating from the bottom plate 11. Connect the connector 120 to the housing 10
a is inserted into the connector mounting hole 16 from the side surface 12a side, and the housing 10a is fixed by screws 125. And FIG.
As shown in (b), the GND part 31 on the back side of the substrate 30
And the outer conductor 123c of the connector 120 are soldered (FIG. 2).
(B) Soldering part 23). Here, although not shown, a structure in which a hole for soldering the bottom plate 11 is formed, or a lid for soldering is formed in the bottom plate 11 is conceivable.

By providing the board fixing portion 19 on the housing inner bottom plate 11 as described above, the solderable space is increased.
And between the bottom plate 11 of the housing 10 and the outer conductor 123, which is the GND portion of the connector 120, and the GND surface 32 of the board 30 can be soldered. Further, the GND surface 32 of the substrate 30 and the housing 1 are formed by the substrate fixing portion 19 and the counterbore 21 provided in the connector mounting hole 16.
The contact portion with zero is reduced. That is, the contact portion between the connector 120 and the connector mounting hole 16 is reduced by the counterbore 21 as compared with the conventional example.

As a result, it becomes difficult for the heat to escape to the housing having high heat dissipation, so that the components mounted on the board 30 can be soldered to the GND surface of the board with heat within the maximum heat resistance standard. By soldering according to the above configuration, the G
The ND surface and the outer conductor 123 of the connector 120 can be directly connected to each other, and the position of the screw for fixing the housing 10a and the board 30 and the number of the screws on the GND surface of the housing 30 depend on the number of the screws. Matching can be reduced, and it becomes easy to output a desired microwave signal to the outside.

Next, another example of the housing 10 will be described. As shown in FIG. 3, the housing 10b has a connector mounting hole 16
It is formed so as to gradually increase from the side surface 12a to the side surface 12b. Also in this case, for the same reason as described above, it is possible to solder the component mounted on the substrate 30 to the GND surface of the substrate with heat within the maximum heat resistance standard. By soldering, the GND surface of the board and the outer conductor of the connector can be directly connected to each other.
The mismatch of the GND plane due to the contact state with the D plane can be reduced,
It becomes easy to output a desired microwave signal to the outside.

<Second Embodiment> Next, a second embodiment of the connection mechanism between the microwave substrate and the connector will be described. In the second embodiment, a substrate having a three-layer structure is housed in a housing, and an inner layer (GND) of the substrate and an outer conductor of a connector are connected by soldering. When a microwave signal modulated and amplified on the substrate having the three-layer structure is output to the outside from the connector, the microwave signal is converted into a microwave signal by connecting the connector to a microstrip line on the substrate which is a microwave transmission path. On the other hand, the mismatch between the GND connection between the board and the connector is minimized.

FIG. 4A shows an example of the substrate having the three-layer structure.
(B). In FIG. 4A, substrates 41, 42
Are two-layer substrates, which are bonded together to form a substrate 40 having a three-layer structure. In this two-layer board 41, the conductor that is on the upper side when the
a, the conductor on the lower side is the conductor 42b, and the conductor on the upper side is the conductor 42a and the conductor 42b on the lower side in the two-layer board 42. Therefore, the conductor 41a is a component surface layer and the conductor 4
1b and the dynamics 42a are inner layers, and the conductor 42b is a solder surface layer. An active element, a passive element, and the like are mounted on the component surface layer. These components are a component surface layer and a second layer.
Assume that they are connected by a microstrip line D. The propagation of the microwave signal on the microstrip line is the propagation mode shown in FIG. here,
It is assumed that wiring and components for a low frequency signal or a DC component which can be considered in a lumped constant circuit are mounted on the solder surface layer.

Further, as shown in FIG.
When 0 is accommodated in the housing, the portion of the two-layer board 42 adjacent to the connector mounting hole 16 is cut out in a rectangular shape. Therefore, the conductor 41b is exposed in the cutout portion 44 of the hatched portion in FIG.

As shown in FIG. 5, a substrate 40 having a three-layer structure is housed in the housing 10a described in the first embodiment, and
0 is placed on the substrate fixing portion 18 and the housing 1 is
0a. The connector 120 is inserted into the connector mounting hole 16 from the side surface 12a, and the
To fix the connector 120 and the housing 10a. The center conductor 121 of the connector 120 is brought into contact with the microstrip line 43 and soldered, and the conductor 41b exposed at the notch portion 44 and the outer conductor 123c of the connector 120 are soldered (the soldering portion 23 in FIG. 5).

As described above, the board 40 is fixed to the board fixing portion 18 of the housing 10a, and the board 40 does not contact the housing bottom plate 11. Therefore, heat dissipation is reduced and
Space for soldering can be secured. And the notch 44
The exposed substrate conductor (inner layer conductor) 41b
Connector outer conductor 123c can be soldered to the micro strip line G existing in the inner layer of the multilayer board.
The ND surface and the GND portion of the connector can be soldered with a heat amount within the maximum heat resistance standard. In this way, conduction can be achieved not only through the through-holes and the housing, but also by directly connecting the GND surface of the board and the outer conductor of the connector. Can be reduced due to the influence of the position and number on the GND plane, and it becomes easy to output a desired microwave signal to the outside.

Next, it is shown by measurement data that the substrate of the second embodiment has a smaller signal attenuation as compared with the substrate in the notch. In this measurement, a high-frequency signal is input from a coaxial connector, and a signal output from the coaxial connector through a microstrip line on a substrate is measured for S-parameters by a network analyzer.

First, the measuring mechanism will be described. FIG. 6 is a configuration diagram illustrating the measurement mechanism 1, and FIG. 7 is a configuration diagram illustrating the measurement mechanism 2. The measuring mechanism 1 uses the outer conductor of the back surface of the four-layer substrate 150 described in the conventional example as the outer conductor 12 of the connector 120.
3 and the measuring mechanism 2 attaches the outer conductor 1 of the connector 120 to the inner conductor 41 b of the three-layer board 40.
23 is soldered. In order to confirm the effectiveness of the cutout portion 44 of the substrate 40, which is a feature of the second embodiment, the material / shape of the housing and the material of the substrate were common. That is, the housing 10c is made of aluminum,
Counterbores were formed in the connector mounting holes of the housings 2 and 14 similarly to the case 10a. Further, the substrates 150 and 40 have a specific electrostatic capacity E
A substrate made of a PPO material with r = 10.5 was used. Then, the connectors 120 are connected to the opposing side plates 12 and 14 of the housing 10a, respectively, and the center conductors 121 of the connectors 120 are connected to connection conductors serving as microstrip lines of the substrates 150 and 40.

The side plate thickness of the housing 10a is L2, the remaining thickness of the side plate in the counterbore portion is L1, the width of the connection conductor, which is a microstrip line of the substrate, is W, the distance between the connection conductor and the GND conductor is p, The distance to the conductor is m.
Further, the distance from the outer shape of the board on the side plate side on which the connector is mounted to the through hole is 11, and the distance between the through holes is l.
2. The width of the notch in the direction parallel to the side plate on which the connector is mounted is k1, and the width of the notch in the direction perpendicular to the side plate on which the connector is mounted is k2. Further, the thickness of the substrate conductor is t, the thickness of the first to second layers of the substrate conductor is h1,
The thickness of the substrate including the substrate conductor is defined as h2. L1 and L2 are
L1 <L2 and a dimension that can be soldered is set. p is a dimension capable of processing the substrate. k
At 1 and k2, the GND portion of the connector and the GND portion of the microstrip line have dimensions that allow soldering. Then, one connector is connected to port 1 of the network analyzer and the other connector is connected to port 2 of the network analyzer.
And measure the S-parameters. Dimension is 10GH
The setting is based on the case where the signal of z passes through the signal line.

The dimensions of the measuring mechanism 1 are shown in Table 1, and the dimensions of the measuring mechanism 2 are shown in Table 2.

[0051]

[Table 1]

[0052]

[Table 2]

In determining W, l1, l2, and p, assuming that the propagation of the microstrip line is the TEM wave mode shown in FIG. 9, the microstrip line characteristic impedance Zc and the effective relative permittivity Er and eff are as follows. .

[0054]

(Equation 1)

The substrate 150 used is Er = 10.
5, since h1 = 5 mm and t = 18 μm, W that satisfies Zc = 50Ω was calculated from equations (1) and (2). Further, the wavelength λg of f = 10 GHz passing through the microstrip line in which W, h1, and t are set as described above.
Is λg = λ0 / (Er, eff) ^1/2 (3) λ0: The wavelength in free space is (3 × 10 ⁸ ) / f [m].

Therefore, the wavelength λg on this substrate = 11.
36 mm. In l1 and l2, p is set to be at least 5 times the W so that the substrate can be processed at λg / 8 or less.

FIG. 8 shows measurement data of the attenuation amount of the signals of frequencies 8 GHz to 12 GHz in the measuring mechanisms 1 and 2 having the dimensions set as described above. It can be seen from FIG. 8 that the signal attenuation is improved. That is, the measuring mechanism 1 generates a portion m where the conductor of the first inner layer, which is the ground conductor, does not exist with respect to the conductor of the component surface of the microstrip line. Are connected. On the other hand, since the measurement mechanism 2 connects the GND of the connector directly to the inner layer conductor, the L property does not occur for the microwave signal, and the microwave signal level is not easily attenuated.

In the second embodiment, the housing in which the counterbore is formed is used. However, the housing in which the connector mounting hole is formed so as to gradually increase from the outside to the inside of the side plate is used. Is also good.

[0059]

According to the present invention, in the connection structure of a substrate for transmitting microwaves by a microstrip line and a connector having a coaxial line structure and outputting a microwave signal from the substrate to the outside, In a mechanism in which the connector and the connector are sandwiched by the housing, the number of connecting portions between the external conductor (GND) of the connector and the housing having high heat dissipation is reduced. By adopting a configuration in which the number of contact portions is reduced, the amount of heat required for soldering is reduced, and the external conductor of the connector can be soldered to the GND portion of the board without affecting the mounted components. Thus, it is possible to reduce the mismatch of the GND portion between the microstrip line and the connector having the coaxial line with respect to the microwave signal, and it becomes easy to output a desired microwave signal to the outside.

Further, the substrate has a multi-layer structure for transmitting microwaves by a microstrip line and a coaxial line structure, and has a multi-layer structure in connection with a connector for outputting a microwave signal from the substrate to the outside. By making the outer shape of the substrate forming the structure such that the GND portion of the microstrip line connected to the center conductor of the connector is exposed, the GND portion of the microstrip line and the outer conductor of the connector (GND) )
Can be soldered, and for microwave signals,
GND mismatch between the microstrip line and the connector having the coaxial line can be reduced, and the amount of signal attenuation can be reduced to easily output a desired microwave signal to the outside.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a housing according to a first embodiment.

FIG. 2 is an enlarged view showing an example of a housing and a substrate accommodated therein.

FIG. 3 is a perspective view showing another example of the housing in the first embodiment.

FIG. 4 is a configuration diagram illustrating a substrate according to a second embodiment.

FIG. 5 is an enlarged view showing an example of a housing and a substrate accommodated therein in the second embodiment.

FIG. 6 is a configuration diagram showing a measurement mechanism 1.

FIG. 7 is a configuration diagram showing a measurement mechanism 2.

FIG. 8 is a characteristic diagram illustrating a relationship between signal attenuation and frequency of the measurement mechanisms 1 and 2;

FIG. 9 is a principle diagram showing microwave propagation on a microstrip line.

FIG. 10 is a perspective view showing a configuration of a housing used in a first conventional example.

FIG. 11 is a configuration diagram showing a configuration of a first conventional connector.

FIG. 12 is a configuration diagram showing a connection mechanism between a board and a connector according to a first conventional example.

FIG. 13 is a configuration diagram showing a housing used in a second conventional example.

FIG. 14 is a configuration diagram showing a substrate used in a second conventional example.

FIG. 15 is a configuration diagram showing a connection mechanism between a board and a connector according to a second conventional example.

FIG. 16 is an enlarged configuration diagram showing a connection mechanism between a board and a connector according to a second conventional example.

[Explanation of symbols]

 10, 10a, 10b, 10c Housing 11 Bottom plate 12, 13, 14, 15 Side plate 16 Connector mounting hole 17 Connector fixing screw hole 18 Board fixing part 21 Counterbore 23 Soldering part 30, 40 Board

Claims (4)

[Claims] 1. A structure of a substrate having a microstrip line accommodated in a box-shaped housing composed of a bottom plate and side plates erected therearound, a center conductor, an outer conductor, and a coaxial line filled with a dielectric between them. A connection mechanism for connecting a connector having the following to the microwave board and the connector via the housing, wherein the housing is formed by a board fixing portion for floating and fixing the board from the bottom plate; And a connector mounting hole formed on the inner side of the side plate and having a larger size on the inner side than on the outer side of the side plate, wherein the substrate accommodated in the housing is fixed to the substrate fixing portion, and the connector is mounted on the connector mounting hole. And connecting the outer conductor of the connector and the GND of the board by soldering. 2. The connection mechanism between a microwave board and a connector according to claim 1, wherein a counterbore is formed inside the side plate having the connector mounting hole and around the hole. 3. The connection mechanism according to claim 1, wherein the size of the connector mounting hole gradually increases from the outside to the inside of the side plate. 4. The substrate according to claim 1, wherein the substrate has a multilayer structure, wherein a GND conductor in an inner layer is exposed to the outside, and the exposed portion is soldered to an outer conductor of the connector.
A connection mechanism between the microwave substrate and the connector according to any one of the above.