JPH06283909A - Circuit element for microstrip line - Google Patents

Abstract

PURPOSE:To mount a microwave circuit with high density by constructing a circuit element without changing the width of a microstrip line. CONSTITUTION:A dielectric substrate 1 contains a ground layer 2 on one of both sides and a strip line 3 formed on the other side respectively. In such a constitution of a microstrip line, a high dielectric constant layer 4 is laminated in an area including a circuit element area between the substrate 1 and the line 3. So that the dielectric constant is partly increased for the dielectric constant placed between the layer 2 and the line 3. Then the impedance of the dielectric member is varied, and a capacity element is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit element of a microstrip line, for example, in a microstrip line used for a microwave integrated circuit and composed of a ground layer sandwiching a dielectric substrate and a strip-shaped line, The present invention relates to a technique for forming a circuit element by changing a characteristic impedance by partially changing a dielectric constant of a dielectric member interposed between a conductor layer and a conductor line.

[0002]

2. Description of the Related Art For example, a microstrip line is used as a microwave transmission line used in a microwave integrated circuit. The microstrip line forms a transmission line by forming a planar ground layer of a conductor layer on one surface of a dielectric substrate such as alumina ceramic and forming a strip-shaped line on the other surface. The characteristics of this strip line are equivalent to those of a coaxial cable developed in a plane, and the characteristic impedance is determined by the width and thickness of the strip line, the dielectric constant of the dielectric substrate, and the thickness.

In such a microwave integrated circuit, circuit elements such as resistors, capacitors, inductors, resonators and bandpass filters are formed by partially changing the characteristic impedance of the microstrip line. An electronic circuit can be constructed.

Conventionally, a method of forming a circuit element using a microstrip line has been to change the characteristic impedance by partially changing the line width of the strip line at the circuit element forming portion. For example, in FIG.
Is a capacitive element configured in a distributed constant manner by changing the characteristic impedance by partially forming the strip line width. When forming the reactance element, conversely, it can be formed by partially narrowing the strip line width.

[0005]

However, in such a conventional circuit element forming method, since the line width is changed, the interval between the adjacent lines is partially changed, and the line is easily affected by the adjacent line. Was becoming. In particular, when a capacitive element is formed, it is easily affected by partially widening the line width, and it is necessary to widen the line spacing in order to secure a sufficient space between adjacent lines. Therefore, the wiring density of the microwave integrated circuit becomes low, which hinders high integration.

Accordingly, an object of the present invention is to provide a structure for forming a circuit element by changing the characteristic impedance of the circuit element of the microstrip line without changing the width of the strip line, thereby improving the microwave integrated circuit. The purpose is to enable high-density wiring, and to downsize and highly integrate the device.

[0007]

In order to solve the above problems, according to the present invention, a strip-shaped conductor line is provided on the other surface of a dielectric substrate having a conductor layer as a ground layer on one surface. In the circuit element structure of the microstrip line in which the microstrip line is formed to form a circuit element by partially changing the impedance of the microstrip line, the dielectric that is interposed between the ground layer and the strip line. The circuit element is configured by partially changing the dielectric constant of a region of the body member including the circuit element forming portion to change the impedance of the portion.

Further, the structure in which the dielectric constant of the dielectric member is partially changed is such that a dielectric layer having a dielectric constant different from that of the dielectric substrate is laminated between the strip line and the dielectric substrate. Can be

[0009]

In such a microstrip line circuit element, since the dielectric constant of the dielectric member between the ground layer and the strip line at the circuit element forming portion is partially changed, the characteristic impedance of that portion is It will be different from other parts. Therefore, for example, a capacitive element can be formed by increasing the permittivity of the circuit element forming portion higher than the permittivity of the dielectric substrate of the other portion, and the reactance element can be formed by lowering the permittivity. You can

Therefore, the circuit element can be formed on the microstrip line without changing the line width of the strip line, and the microwave circuit can be mounted at a high density and the degree of integration can be increased.

Further, layers having different permittivity can be laminated by a method such as printing a dielectric paste different from the permittivity of the dielectric substrate on the dielectric substrate, so that the permittivity of the dielectric member can be easily varied. , And various circuit elements having different impedances can be easily formed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a structure of a circuit element of a microstrip line according to an embodiment of the present invention, and FIG. 2B is a schematic view of the circuit element of FIG. 1 seen from above.

Alumina ceramic (dielectric constant: ε = 9.
4) and the like, a conductor ground layer 2 made of Cu or the like is laminated on one surface of the dielectric substrate 1, and an elongated flat plate-like strip line 3 forming a microwave circuit is formed on the other surface. Has been done. A high dielectric layer 4 having a dielectric constant higher than that of the dielectric substrate 1 is formed between the strip line 3 at the capacitive element forming portion of the microwave circuit and the dielectric substrate 1. The high-dielectric layer 4 is formed by printing a high-dielectric paste, an Ag strip line is formed on the high-dielectric paste, and the strip line 3 is formed by applying an electroless Cu plating layer to the strip line.
To form.

In the above structure, the dielectric substrate 1
In the region where the high dielectric layer 4 is laminated, the dielectric constant of the high dielectric layer 4 is combined with the dielectric constant of the dielectric substrate 1, so that the dielectric member interposed between the strip line 3 and the ground layer 2 is formed. The permittivity as a whole is partially increased. Therefore, as the impedance changes and the dielectric constant between the electrodes increases, the capacitance increases in a distributed constant manner, so that a capacitive element is formed in that portion.

In this embodiment, the capacitive element is formed by forming a dielectric layer having a higher dielectric constant than that of the dielectric substrate. However, a dielectric layer having a lower dielectric constant than that of the dielectric substrate is formed. It is also possible to partially reduce the dielectric constant of the dielectric member to form a reactance element.

Further, in this embodiment, the dielectric constant is changed by laminating the high dielectric layers, but the present invention is not limited to the means for laminating dielectric members having different dielectric constants, and a dielectric substrate is formed. It is also possible to use a method of forming the circuit element formation planned portions at different stages with materials having different dielectric constants.

Further, although the strip line is formed in a straight line in the present embodiment, the method of forming a circuit element by partially changing the line width as in the conventional method may be used in combination, and the spiral line may be used. You may combine with other line patterns, such as shape.

[0018]

As described above, according to the present invention, the circuit element can be formed by changing the impedance without changing the strip line width, so that the influence of the adjacent line can be prevented in the microwave circuit. Therefore, it is not necessary to widen the space between the adjacent lines, and high-density mounting is possible. Therefore, the degree of integration of the microwave integrated circuit can be significantly increased and the device can be downsized.

Further, by printing a dielectric paste or the like different from the dielectric substrate on the dielectric substrate to partially change the dielectric constant, it becomes extremely easy to control the impedance of the circuit element, so that the microwave integrated circuit can be controlled. The performance of can be greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a circuit element of a microstrip line according to an embodiment of the present invention.

FIG. 2 is a plan view showing a structure of a conventional microstripline capacitive element stripline (a) and a microstripline capacitive element (b) according to an embodiment of the present invention.

[Explanation of symbols]

 1 Dielectric Substrate 2 Ground Layer 3 Stripline 4 High Dielectric Layer

Claims (2)

[Claims] 1. A circuit element is provided by partially changing the impedance of a microstrip line in which a strip-shaped conductor line is formed on the other surface of a dielectric substrate having a conductor layer as a ground layer on one surface. In the circuit element of the microstrip line to be formed, by partially changing the dielectric constant of the region of the dielectric member interposed between the conductor layer and the conductor line, the region including the formation position of the circuit element. , A circuit element of a microstrip line characterized in that the circuit element is formed by changing the impedance. 2. The conductor layer and the conductor line are formed by laminating a dielectric layer having a dielectric constant different from that of the dielectric substrate between the conductor line and the dielectric substrate. The circuit element of the microstrip line according to claim 1, wherein the dielectric constant of the dielectric member interposed between the two is partially changed.