JPS6224967Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a coaxial-microstrip line connection circuit provided in a microwave integrated circuit device. Generally, when a microwave integrated circuit (hereinafter referred to as MIC circuit) made up of microstrip lines is placed in a case and connected to a coaxial connector, the method shown in FIG. 1 is conventionally used. 1 in Fig. 1 is the case, and the coaxial connector outer conductor 2 is the case 1.
The connector center conductor 3 is attached to the
It is connected to the microstrip line 5 on the MIC board 4. To complete this connection, a microstrip line 5 is usually welded as the connector center conductor 3 via gold foil 6 or the like. Also, 7 is a carrier plate, and on this
A MIC board 4 is mounted, and a carrier plate 7 is attached to the case 1. In such a configuration, the radius of the connector outer conductor and the thickness of the MIC board 4 generally differ significantly, so as shown by the arrows in FIG. As a result, the electric field distribution changes rapidly at the boundary portion 8 of the connection portion, causing disturbance and mismatch. Conventionally, in such a structure, this mismatch has been solved by adjusting the MIC circuit, such as by putting gold foil on the microstrip line 5. For this reason, a great deal of time is spent on adjustment work, and in some cases, adjustment is impossible in circuits intended to widen the band. Furthermore, the MIC board 4 attached to the case 1
When removing the connector, the gold foil 6 for connection must be removed and the connector must be unplugged. Therefore, it was extremely difficult to replace and install the board. Furthermore, after the connector center conductor 3 and the gold foil were connected, the connection points sometimes came off due to vibrations or changes in ambient temperature. This idea was made in order to eliminate the above-mentioned drawbacks of the conventional method, and it connects a metal foil plate, such as a copper foil plate, between the coaxial connector center conductor and the microstrip line. It is an object of the present invention to provide a microwave integrated circuit device having a coaxial-microstrip line connection circuit capable of eliminating generation. Embodiments of the microwave integrated circuit device of this invention will be described below with reference to the drawings. Figure 2a
is a plan view showing the configuration of one embodiment;
Figure b is a front view. In the embodiments shown in FIGS. 2a and 2b, the coaxial connector and the microstrip line are connected using a metal foil having the shape shown in FIG. 3. The lower part of the outer conductor 10 of the connector 9 is attached so as to be substantially flush with the surface 11 of the case, and is also attached at a distance. Further, one end of the metal foil is bent, a through hole 13 is provided in this bent portion, and the center conductor 12 of the connector 9 is inserted into the through hole 13 and connected by soldering or the like. The center part 14 of this metal foil is arranged approximately parallel to the surface 11 of the case that serves as a ground conductor, and a second wing-shaped stub 15 is formed in this center part 14. It is bent.
The other end of the metal foil is bent to form a sloped part 16, and the tip 17 of this sloped part 16 has approximately the same width as the microstrip line 19 on the MIC board 18. Connected by welding etc. Furthermore, first stubs 21 for alignment are formed on both sides of the inclined portion 16. Note that this metal foil is preferably plated with gold so that welding (such as thermocompression bonding) and soldering can be easily performed. The MIC board 18 is bonded to a carrier plate 20 with solder or the like, and the carrier plate 20 is tightly attached to the case surface 11 with screws or the like. By configuring as above, the connector 9
Since the outer conductor 10 and the case surface 11 are connected without any difference in level, the electromagnetic field distribution shown by the arrows in the figure is transmitted without being disturbed. Next, the electromagnetic field reaching the central part 14 of the gold foil is guided to the microstrip line 19 through the part 16 that is inclined with respect to the case surface 11 which is a ground conductor, that is, the right part 16. With such a structure, the electromagnetic field is not suddenly changed and is gradually guided to the microstrip line, so mismatching is less likely to occur. Here, metal foil and case surface 11
A microstrip line is formed to transmit an electromagnetic field, and the line characteristic impedance of this part must be 50Ω. Generally, when the width of the microstrip line is w and the gap between this and the ground conductor is h, the characteristic impedance Zc can be expressed by the following equation. It is. The source of this equation (1) is MARGuston,
Microwave Transmission−Line Impedance
Data, PP42−43, Van Nostrand Reinhold Co,
New York, 1972. Since ε _eff =1 in air, substituting this into equation (1) and finding w/h when Zc = 50Ω yields w/h = 4.9. From this, the width w of the central portion 14 of the metal foil is determined by the distance h from the ground conductor 11.
Then, it becomes 4.9h. Next, since the electric field in the inclined portion 16 is as shown in FIG. 2, the effective distance h from the ground conductor can be considered to be the length of the electric wire indicated by the arrow in the figure. Using this length h, the first stub 2 is adjusted to the width of the inclined portion 16.
We can calculate w ₂ by adding the width of 1. In this way, when the width of the metal foil in the configurations shown in FIGS. 2a and 2b is determined, the shape as shown in FIG. 3 is obtained. A second stub 15 attached to the central portion 14 of the metal foil then compensates for the lead inductance of the central conductor 1 of the connector 9. If the lead inductance is L and the capacitance of the stub 15 is C, then

Select C so that [formula] is satisfied. This value of C is adjusted by adjusting the bending angle of the second stub 15. As mentioned above, in the microwave integrated circuit device of this invention, a coaxial-microstrip line connection circuit formed by bending metal foil is connected between the center conductor of the connector and the microstrip line. As a result, impedance mismatch occurring at the connection between the two can be removed, and a signal incident from the connector can be guided to the microstrip line without being reflected. In particular, the connection between the center conductor of the connector and the metal foil is
Connections are made by inserting the center conductor into a through-hole in the metal foil, making it easy to work with, and ensuring reliability as the connection will not come off due to vibrations or changes in ambient temperature even after connection. Are better. In addition, according to the configuration of this invention, it is only necessary to connect the metal plate between the connector and the microstrip line, which improves the workability of assembly.
When replacing the MIC board, there is no need to remove the connector, making the work even easier.

[Brief explanation of the drawing]

FIG. 1 is a sectional view for explaining the method of connecting coaxial-microstrip lines in a conventional microwave integrated circuit device, and FIG. A plan view showing an example of the line connection circuit, 2nd
FIG. 3 is a sectional view of the microstrip line connection circuit as described above, and FIG. 3 is a plan view showing the shape of the metal foil for connection used in the coaxial-microstrip line connection circuit as described above. 9... Connector, 10... Outer conductor, 11... Case surface, 12... Center conductor, 13... Hole in metal foil, 14... Center portion of metal foil, 15... Second stub, 16... ... Inclined part, 17... Tip part, 18...
...MIC board, 19...microstrip line,
20...Carrier plate, 21...First stub.

Claims (1)

[Claims for Utility Model Registration] An MIC board housed in a case and on which a microwave integrated circuit is formed, and a coaxial connector provided in the case, in which the distance between the center conductor and the outer conductor is different from the thickness of the MIC board. and a coaxial-microstrip line connection circuit that connects the center conductor of the coaxial connector and the MIC board, wherein the coaxial connector is connected to the lower part of the outer conductor and the
The coaxial-microstrip line connecting circuit is provided at a distance so that the bottom surface of the MIC board is substantially flush with the bottom surface of the MIC board, and one end of the coaxial-microstrip line connecting circuit is bent, and the center conductor of the coaxial connector is inserted into this bent portion. It has a through hole to be connected, and the other end has an inclined part that is inclined to the height of the microstrip line of the microwave integrated circuit, and the width of the tip of this inclined part is equal to the height of the microstrip line of the microwave integrated circuit. is set to the same width as
Further, first stubs are provided on both sides of the inclined portion to align with the microstrip line and the coaxial connector with respect to the height from the bottom of the case, and second stubs are provided on both sides of the central portion. A microwave integrated circuit device characterized in that it is formed of a metal foil provided with.