JPH0354863B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a microwave circuit device that can be used in a MIC (Microwave IC) high frequency amplifier using transistors used in a microwave communication device.

Conventional configurations and their problems In recent years, MIC circuits in which a microstrip line circuit is formed on a dielectric substrate have become commonly used as the circuit configuration for microwave communication equipment. When constructing the amplifier used, if the transistors are not grounded reliably, the gain will decrease and the operation will become unstable.

A conventional microwave circuit device will be described below with reference to the drawings. FIG. 1 is a drawing of the main part of a conventional MIC amplifier where transistors are arranged. Figure a shows input/output microstrip lines 3a and 3b on a dielectric substrate 1 having a back conductor 2.
A through hole 4 having a conductor forming a conductor and connecting the back conductor 2 to the inside thereof for grounding the transistor.
FIG. 4 is a perspective view of the main parts of the MIC board on which portions a and 4b are formed. Figure b is a perspective view of the main parts of the transistor 5 mounted on the MIC board shown in figure a, with 6a and 6b
is an emitter terminal to be grounded, and 7 and 8 are a base terminal and a collector terminal for signal input/output, respectively. Figure c is a sectional view taken along line A-A' in figure b.
Furthermore, figure d is a sectional view taken along line BB' in figure b.
Note that 12 indicates a stray capacitance generated between the input and output terminals of the transistor.

Now, in the above-mentioned MIC amplifier, stray capacitance occurs between the input and output terminals 7 and 8 of the transistor 5, as shown in Figure 1d, which may cause the circuit to oscillate or malfunction. It had the disadvantage of being unstable.

OBJECTS OF THE INVENTION An object of the present invention is to provide a microwave circuit device capable of stabilizing circuit operation by reducing stray capacitance between input and output of a microwave band MIC amplifier.

Structure of the Invention The microwave circuit device of the present invention is provided on a dielectric substrate provided with a through hole in the shape of a narrow slit connecting two holes for inserting two ground terminals of a transistor. A microstrip line is provided on both sides of the slit portion of the through hole so as to be perpendicular to it, and a ground conductor is formed on the remaining surface of the dielectric substrate, and the ground conductor is formed inside the through hole. The transistor is provided in the center of the through hole, its input and output terminals are respectively connected to the microstrip line, and the ground terminal of the transistor is connected to the two holes. The transistor is connected to the ground conductor at the two holes, and the transistor can be grounded at the two holes, and the stray capacitance generated between the input and output terminals of the transistor can be reduced by connecting the ground conductor to the ground conductor at the narrow width. The slit-like penetrations have the advantage of being able to be reduced.

DESCRIPTION OF EMBODIMENTS FIG. 2a is a perspective view of essential parts of a MIC board used in a microwave circuit device according to a first embodiment of the present invention.
In the figure, 13 is a dielectric substrate, 14 is a back conductor, 1
5 and 16 are input and output microstrip lines, 17a and 17b are circular through holes,
18 is a narrow slit, and a circular through hole 1
It extends to connect 7a and 17b. Incidentally, the through holes 17a, 17b and the slit 18 have conductors formed inside thereof so as to connect the back conductor 14. Figures 2b and c are the second
FIG. 2 is a cross-sectional view taken along line CC' and line D-D' in FIG.
FIG. 3a is a top view of the microwave circuit device shown in FIG. 2, in which transistors are mounted on the MIC board. In the same figure, 19 is a transistor package,
20a and 20b are emitter terminals to be grounded;
1 and 22 are an input base terminal and an output collector terminal, respectively. 23a, 23b,
24 and 25 are soldered parts. FIGS. 3b and 3c are sectional views taken along line EE' and line FF' of FIG. 3a, respectively. In addition, 26a and 2
6b is the capacitance between the input/output terminal of the transistor and the ground conductor inside the slit.

In the microwave circuit device configured as described above, the transistor can be grounded very close to the transistor package 19, and the stray capacitance generated between the input and output of the transistor can be connected in series as shown in FIG. 3c. Since a part of the feedback capacitance becomes a parallel additional capacitance, the series feedback capacitance is reduced, the circuit is less likely to fall into an oscillation state, and the circuit operation is stabilized.

Figure 4 shows the MIC used in the second embodiment of the present invention.
FIG. 3 is a perspective view of the main parts of the board. In the figure, 27 is a dielectric substrate, 28 is a back ground conductor, 29 and 30 are input and output microstrip lines, and 31a
and 31b are rectangular through holes matching the shape of the electrodes to be grounded of the transistor, and 32 is a narrow slit extending so as to connect the through holes 31a and 31b. Note that a conductor is formed inside the through holes 31a, 31b and the slit 32 so as to be connected to the back conductor 28. FIG. 5 is a perspective view of the transistor to be mounted. In the figure, 33 is a transistor package, 34a and 34b are grounding emitter terminals bent to fit into the two rectangular through holes 31a and 31b of the MIC board shown in FIG. 4, and 35 and 36 are input terminals, respectively. The base terminal and the collector terminal of the output. FIG. 6a is a top view of essential parts of a microwave circuit device in which the transistors shown in FIG. 5 are mounted on the MIC board shown in FIG. 4. In the same figure, 37a, 37b, 3
8 and 39 are soldered parts. Figure 6b
and c are the GG' and H-H' sectional views of FIG. 6a, respectively.

In the microwave circuit device configured as described above, the grounding of the transistor can be obtained in the close vicinity of the transistor package 33, and the floating amount generated between the input and output of the transistor can be reduced by the slit-shaped through hole 32 having a ground conductor. Therefore, the circuit operation can be stabilized.
Furthermore, by bending and inserting the ground terminals 34a and 34b of the transistors into the rectangular through holes 31a and 31b, it is possible to clarify the placement position of the transistors.

FIG. 7 is a perspective view of essential parts of a MIC board used in a microwave circuit device according to still another embodiment of the present invention.
In the figure, 40 is a dielectric substrate, 41 is a back conductor, and 4
2 and 43 are input/output microstrip lines, 44a and 44b are square through holes, and 45a and 45b are square through hole portions 44.
a semicircular through hole connecting to a and 44b, 46
are narrow slits through holes 44a and 44b.
It stretches out as if tying it together. Note that the through holes 44a,
A conductor connected to the back conductor 41 is formed inside the through hole made up of 44b, 45a, 45b and the slit 46. Figure 8a is the MIC of Figure 7.
6 is a top view of essential parts of a microwave circuit device in which the transistor of FIG. 5 is mounted on a substrate. FIG. In the same figure, 47a
Reference numerals 47b and 47b represent the soldering portions of the ground terminals of the transistors, and the semicircular through holes 45a and 45b are filled with solder. 48 and 49 are input/output microstrip lines 42 and 43, respectively.
This is the soldered portion of the connection between the input and output terminals 35 and 36 of the transistor. FIGS. 8b and 8c are a sectional view taken along line I-I' and sectional view taken along line J-J' in FIG. 8a, respectively.

Now, in the microwave circuit device configured as described above, by filling the semicircular penetration parts 45a and 45b of the grounding part of the transistor with solder, the grounding can be more reliably achieved than in the case of only a rectangular penetration hole. It will be done. At the same time, stray capacitance between the input and output terminals of the transistor is reduced by the slit-shaped through hole 46, making it possible to stabilize circuit operation. Further, by bending the ground terminals of the transistors and inserting them into the rectangular through holes 44a and 44b, it becomes easy to determine the placement position of the transistors.

Note that in the above embodiments, the shape of the through hole connecting the ground terminal of the transistor was circular, square, or a combination of square and circular, but the shape is not limited to these. Any other shape may be used as long as it can ground the ground terminal of the transistor.

Effects of the Invention As is clear from the above description, the present invention provides a dielectric substrate having a through hole in which two holes for inserting two ground terminals of a transistor are connected by a narrow slit. A microstrip line is provided on both sides of the through hole so as to be perpendicular to the slit portion of the through hole, and a ground conductor is formed on the remaining surface of the dielectric substrate, and a ground conductor is provided inside the through hole. A conductor is formed so as to be connected to the ground conductor on the one surface, the transistor is provided in the center of the through hole, its input and output terminals are respectively connected to the microstrip line, and the transistor is connected to the ground conductor. Since the microwave circuit device has a structure in which the terminals are connected to the ground conductor at the positions of the two holes, the transistor can be grounded very close to the transistor package. Depending on the part, stray capacitance generated between the input and output terminals of the transistor can be reduced, and the effect of preventing the circuit operation from falling into an oscillation state and stabilizing it can be obtained.

[Brief explanation of drawings]

Figure 1 shows the main parts of a conventional MIC amplifier.
Figure a is a perspective view of the MIC board, Figure b is a perspective view of the main parts of an MIC amplifier with transistors mounted, Figure c is A-A' cross-sectional view, Figure d is B-B' cross-sectional view,
Figure 2a is a perspective view of essential parts of the MIC board according to the first embodiment of the present invention, Figure 2b is a sectional view taken along line C-C', and Figure 2c is a cross-sectional view of D
-D' sectional view, FIG.
E' cross-sectional view, Figure c is F-F' cross-sectional view, Figure 4 is a perspective view of essential parts of the MIC board according to the second embodiment of the present invention, and Figure 5 a is the second embodiment of the present invention. A perspective view of a packaged transistor used in a MIC amplifier.
FIG. 5b is a rear view thereof, and FIG. 6a is a second view of the present invention.
A top view of the main parts of the MIC amplifier according to the embodiment, Figure b
is a sectional view taken along the line G-G', c is a sectional view taken along the line FF', and FIG.
FIG. 8a is a top view of essential parts of an MIC amplifier according to another embodiment of the present invention, FIG. 8b is a sectional view taken along line I-I', and FIG. 8c is a sectional view taken along line J-J'. 18... Narrow slit, 26a, b... Stray capacitance between the input/output terminal of the transistor and the inner ground conductor of the narrow slit, 31a, b... Rectangular through hole, 3
2...Narrow width slit, 45a, b...Semicircular through hole, 46...Narrow width slit.

Claims (1)

[Scope of Claims] 1. A dielectric substrate having a through hole in which two holes for inserting two ground terminals of a transistor are connected by a narrow slit, and a slit portion of the through hole. A microstrip line is provided on both sides of the dielectric substrate, and a ground conductor is formed on the remaining surface of the dielectric substrate, and a conductor is formed inside the through hole to be connected to the ground conductor. and disposing the transistor on the dielectric substrate so as to correspond to the center of the through hole,
A microwave circuit device characterized in that input and output terminals of the transistors are respectively connected to the microstrip line, and ground terminals of the transistors are connected to the ground conductor at the positions of the two holes. 2. The microwave circuit device according to claim 1, wherein the two holes into which the two ground terminals of the transistor are inserted are each formed in a square shape.