JPS63261901A - Strip line for microwave hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To facilitate the forming of a microwave hybrid integrated circuit by laminating a ground conductor layer, a dielectric layer and a strip conductor layer to one face of an insulating board. CONSTITUTION:The ground conductor layer 2, the dielectric layer 3 and the strip conductor layer 4 are laminated on one face of an insulating board crystal ceramic dielectric board 1 by vapor-deposition processing. In forming the layers by similar thermal expansion coefficient, the effect of distortion due to temperature change is decreased. Then the other side of the board is shielded by high frequency by the layer 2 and other circuit is mounted freely in the microwave hybrid integrated circuit, which is formed easily by one side processing only.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microwave hybrid integrated circuit having a microwave stripline.

[Conventional technology]

Conventionally, regarding microwave strip lines formed in microwave hybrid integrated circuits, Japanese Patent Publication No. 60
As shown in Japanese Patent No. 14521, a dielectric material is provided on a plate-shaped ground conductor such as a metal plate as a substrate, and a strip conductor is further formed on the substrate to form a strip line. Further, a dielectric is used as a substrate, and a ground conductor is formed on one side of the substrate, and a strip conductor is formed on the opposite side.

[Problem that the invention seeks to solve]

Problems with the above-mentioned conventional technology include the following.

When the ground conductor is used as a substrate, it is necessary to use a substrate with a small thermal tensile coefficient, and there are restrictions on the types of materials that can be used.

Further, even if a substrate with a small coefficient of thermal expansion is used, the coefficient of thermal expansion of the substrate is considerably large compared to that of the dielectric material formed thereon. Therefore, it also depends on the dielectric material.

But it will be limited.

When a dielectric is formed on a metal plate as a substrate, the dielectric layer must be particularly thick in order to maintain the necessary mechanical strength in order to mount components, etc. Therefore, it is necessary to The pattern width also becomes wider, making it unsuitable for miniaturization.

That is, conventionally, when a strip line is formed on a crystalline ceramic dielectric substrate with a board thickness of 0@B1 m (ratio u t 'its gr = 9,6, working frequency f: 800 MHz vC), the width W of the strip conductor becomes Q, 9 mm. , and has a fairly large area, so there is a limit to miniaturization.

Furthermore, the board must include not only strip lines but also component rounds to incorporate electronic circuits that utilize them, so stray capacitance between component rounds becomes a problem, especially when the dielectric must be thick. becomes. This may cause oscillation, especially when a high gain amplifier is used.

When a high-frequency circuit is built into a board with a dielectric layer formed on a ground conductor, and other circuits are built into a part of the board, the ground conductor is placed under this circuit through the dielectric. Therefore, it is unavoidable that stray capacitance will occur between this circuit and the ground conductor.

Although it is possible to suppress the generation of stray capacitance by using an insulator in a part of the substrate, such a substrate has the disadvantage that it has a complicated structure and is expensive.

Furthermore, when making a compact hybrid board and attaching lead pins to the board, it is necessary to perfect the insulation between the lead pins and the board, which requires a complicated process.

In addition, in order to make the strip line compact, - In order to shorten the effective wavelength, use a material with a large 6R - Interfusion between the ground conductor and the strip conductor, that is, l! The viewing layer must be made thin, but if a dielectric substrate is used, it cannot be made thin in order to maintain mechanical strength, and a dielectric with a high specific electric constant Mr must be used. This greatly limits the selection of the types of materials to be used, causing design problems.

Further, when a dielectric material is used as a substrate, there is a problem in that both sides must be processed, which increases the number of manufacturing steps.

Furthermore, the input impedance of transistors etc. is 5 to 2
Since it is extremely low at 0Ω, it was necessary to take up a fairly large conductor area in order to match the impedance of the strip line.

[Means for solving problems]

The present invention uses an insulator as a substrate, forms a conductor to serve as a ground conductor on the substrate by printing, vapor deposition, or other methods, forms a dielectric material on top of the dielectric material, and further forms a strip conductor on top of that. , which solves the problems in the prior art described above.

[For production]

The stripline formed as described above requires processing only on one side when configuring the microwave stripline on the substrate, and when using a material with a similar expansion coefficient, the effect of distortion on expansion due to temperature changes can be avoided. It can be reduced.

Further, since a conductor is formed on the back surface of the dielectric to form a strip line, the ground conductor of the microwave strip line provides a state of high frequency shielding from other surfaces of the ground conductor. Therefore, it is possible to freely assemble another circuit that is not subject to high-frequency interference on other surfaces of the insulator substrate, and to easily connect the strip line on the insulator substrate and other parts electrically. . Therefore, all sides of the substrate can be used effectively.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

A conductor such as Ay/Pb (silver palladium) paste or EU (copper) paste is printed on the crystal ceramic dielectric substrate 1 and fired to form a ground conductor layer 2 (FIG. 1A). Next, a dielectric paste such as glass is printed on the ground conductor layer 2 and fired to form a "C dielectric layer 5" (see Figure 1B).
). Further, At/PA or CLL paste is printed thereon to form the strip conductor 4 (FIG. 1C).

fil 111D shows a hybrid integrated circuit with a microwave stripline formed in this way. The impedance Z of the microwave strip arm formed in this manner is generally determined by the following equation using the thickness of the dielectric layer 5, the relative dielectric constant 1r, and @W of the strip conductor 4.

Note that by using materials 2 and 5 formed on the insulating substrate 1 with expansion coefficients similar to those of the insulating substrate 1, a /1 hybrid integrated circuit without the problem of thermal expansion distortion can be obtained. can.

FIG. 2 shows another embodiment according to the present invention, in which microwave strip conductors 4 are similarly formed on both sides of an insulating substrate 1 by the above-described means.

In FIG. 5, an insulator substrate 1 is used as a substrate, and a ground conductor 2. A hybrid integrated circuit board having a dielectric layer 5 and a strip conductor 4 formed thereon.

In the plate, the ground conductor 2 is commonly used on the opposite surface (lower surface) of the insulating substrate, and a dielectric layer 5 and a microwave strip line 4 are formed thereon in the same manner as in the above means. This shows an example.

FIG. 4 shows that a conductor layer 2 and a dielectric layer 5 are formed on the other surface of the insulator substrate 1 on which other circuits are formed by the same method as described above.
2 shows an example in which a microwave strip line 4 is formed.

FIG. 5 shows an embodiment in which a circuit provided on the opposite side of the insulating substrate 10 is electrically connected to the strip line 4 by a hole provided in the insulating substrate 1.

First, the ground conductor 2 is formed by providing a part slightly thicker than the hole to avoid the hole so as not to block the hole provided in the board 1 and to prevent it from entering the hole. Further, a dielectric layer 5 is formed by providing a hole-avoiding portion in the same manner as the ground conductor 2. Further, a strip conductor 4 is formed on the dielectric layer 5 to form an integrated circuit according to this embodiment.

The strip conductor 4 formed above the hole can be electrically connected to the other surface of the insulator substrate 1 through the hole, but the upper IJ tube conductor 4 and the lower ground groove/body 2 are connected around the hole. In order to avoid contact at the parts, when forming the dielectric layer 5, the part to avoid the hole is made smaller than the lower ground conductor 2, so that the exposed part of the ground conductor 2 is reduced.

FIG. 6 shows a modification of the embodiment shown in FIG. 5 in which the ground conductor 2 formed on the surface of the insulator substrate 10 is not provided with a hole-avoiding part, and the strip conductor 4 is grounded. A circuit electrically connected to the conductor 2 and formed on one surface of the insulating substrate 1 is electrically connected to the ground conductor 2 provided on the other surface through the hole.

FIG. 7 shows another modified embodiment in which the hole passing through the insulator substrate 11C is not provided as described above, and the strip conductor 4 is electrically connected to the ground conductor 2.

However, it is not connected to other circuits placed on the opposite side.

〔Effect of the invention〕

According to the invention, printing, vapor deposition or other methods.

Since a ground conductor, a dielectric layer, and an IJ tube conductor are all constructed on an insulating substrate, at the design stage, the relative permittivity εr of the dielectric layer and the thickness of this dielectric layer are determined.

The width W of the strip conductor can be freely selected.

In particular, the problem of stray capacitance when a ground conductor is used as a substrate, and the problem that when a dielectric is used as a substrate, both sides must be processed and the manufacturing process increases are eliminated, and according to the present invention, only one side of the substrate is required. It is possible to configure all of them, and even in that case, there is an extremely excellent effect that no stray capacitance occurs.

Furthermore, when a dielectric material is used as the substrate, there is an effect that there is no need to consider such a problem of stray capacitance, and there is also a significant effect in terms of manufacturing cost since double-sided processing is not required in the manufacturing process.

For example, with the conventional method, it was quite difficult to make the strip conductor width W = 0.6 mm or less to make a 50 Ω line when using a crystalline ceramic dielectric substrate, but according to the present invention, it is difficult to make the strip conductor width W = 0.6 mm or less. To make a railway line, gy=
If you use the materials in step 5, A: 60fim.

W = 150 μm, and if a material with #y = = 5.5 is used, A = 40 μs and W = 100 μm, so it can be freely designed according to manufacturing technology, making it easy and inexpensive to configure a VC. There is a possible effect.

In addition, the input impedance of transistors etc. is 5 to 20
Because the Ω is very low, the conductor surface #lC is small even for input lines that have been quite large up until now.

Therefore, impedance matching t5 of the strip line can be achieved.

In the device of the present invention, a line passes through from the strip conductor surface to the back surface of the ground conductor (the number of electric lines of force has no relation to the charge on the back surface of the substrate. Therefore, in the special present invention, the M911vC of the board No processing work required.

Furthermore, since the ground conductor layer has a shielding function, other circuits can be incorporated as they are without considering high frequency interference, and both sides of the board can be used effectively.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the manufacturing process of a microwave hybrid board according to an embodiment of the present invention, and FIGS.
The figure is a diagram showing a schematic cross-sectional view of the modified example. 1...Grounding conductor layer 2...Dielectric layer 6...Strip conductor 4...Crystal ceramic dielectric substrate B

Claims (1)

[Claims] 1. A ground conductor layer formed on one surface of an insulating substrate, a dielectric layer formed on the ground conductor layer, and a strip conductor layer formed on the dielectric layer. A microwave hybrid integrated circuit strip line characterized by comprising: 2. A ground conductor layer formed on one surface of the insulator substrate, a first dielectric layer formed on the ground conductor layer, and a second dielectric layer formed on the other surface of the insulator substrate. 1. A strip line for a microwave hybrid integrated circuit, comprising a first strip conductor layer and a second strip conductor layer formed on the first and second dielectric layers, respectively. 3. The strip line of the microwave hybrid integrated circuit according to claim 1, further comprising another circuit on the opposite surface of the insulating substrate.