JPH11251857A - Laminated filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laminated filter which has been designed for easily realizing desired characteristics. SOLUTION: Signal lines 3a to 3c and ground lines 2a to 2d are alternately arranged by respectively inserting dielectric layers 1a to 1i in a laminating direction. Ground lines 4a to 4c and 5a to 5c apart from the lines 2a to 2d are respectively provided for the same layers with the lines 3a to 3c for respective layers. The lines for the respective layers are mutually connected, and both their ends are connected to the input terminal and the output terminal of the outer surface of the main body. The lines 2a to 2d, 4a to 4c and 5a to 5c are mutually connected, and only one terminal of the ground lines are connected to the ground terminal of the outer surface of the main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed constant type laminated LC filter used as a noise filter or the like.

[0002]

2. Description of the Related Art FIG. 9A is a view showing a laminated structure of a laminated filter disclosed in Japanese Patent Laid-Open No. 4-2108.
(B) is an equivalent circuit diagram thereof. In FIG. 9A,
60a to 60g are insulator layers, 61a to 61c are FIG.
(B) First conductors constituting the coil 61, 62a to 62a
Reference numeral 2c denotes a second conductor facing the first conductors 61a to 61c via an insulating layer, and constitutes the coil 62 shown in FIG. 9B. 63, 64 are first conductors 61a to 61, respectively.
c, a connection conductor for the second conductors 62a to 62c, and 65 is a via hole. Both ends of the first coil 61 are connected to an input terminal 66 and an output terminal 67, and both ends of the second coil 62 are connected to terminals 68 and 69.

[0003]

As shown in FIG. 9, in the laminated filter in which the first conductors 61b and 61c and the second conductors 62b and 62c having the structure of being circulated face each other in the laminating direction, different characteristics are obtained. In order to obtain, to change the capacitance, these conductors 61b, 61c, 62b,
It is necessary to change the shape of 62c to increase or decrease the facing area, change the thickness of the insulator layer between the conductors, or change the dielectric constant of the insulator layer. Therefore, there is a problem that it is not easy to design to obtain the desired characteristics. For example, conductors 61a to 61c, 62a to 6
It is not easy to grasp the change of the facing area due to the change of the shape of 2c, and it is not easy to grasp the change of the capacitance.
Since not only the capacitance but also the inductance tends to change, it is difficult to obtain the desired characteristics.

[0004] In view of the above problems, it is an object of the present invention to provide a laminated filter having a configuration that can easily obtain desired characteristics in design. Another object of the present invention is to provide a multilayer filter having a configuration in which the capacitance can be easily increased. Further, the present invention provides a multilayer filter having a configuration in which a high capacitance value can be obtained by miniaturization, the degree of capacitive coupling between each line and a terminal is reduced, and the original capacitive coupling between each layer is easily obtained. Another purpose is to provide

[0005]

(1) According to a first aspect of the present invention, a signal line and a ground line are alternately arranged via a dielectric layer in a laminating direction, respectively, and are arranged in the same layer as the signal lines of the respective layers. A ground line different from the ground line is provided, the signal lines of the respective layers are connected to each other, and both ends thereof are connected to an input terminal and an output terminal on the outer surface of the base, and the ground lines are connected to each other to ground. Only one end of the line is connected to a ground terminal on the outer surface of the base.

In the first aspect, for example, the pattern of the signal line of each layer is not changed, and the length of the ground line or the signal line facing the signal line in the stacking direction and the distance between the ground line of the same layer and the signal line are set. When it is changed, the capacitance can be changed, and the capacitance can be changed without changing the inductance of the signal line, so that a desired filter characteristic can be easily obtained. (2) The invention of claim 2 is characterized in that, in claim 1, ground lines provided on the same layer as the signal lines of the respective layers are provided on both sides of the signal lines of the respective layers.

According to the second aspect, by providing the ground lines on both sides of the signal line, a higher capacitance can be obtained as compared with a case where the ground lines are simply provided in the stacking direction and on one side of the signal line. Further, by changing the length and the like of the ground lines on both sides of the same layer of the signal line, the range of change of the capacitance is expanded. (3) In the third aspect of the present invention, in any one of the first and second aspects, the signal line and the ground line are opposed to each other in the stacking direction, or at least one of the opposed portions facing each other in the same layer. The dielectric constant of the body layer is higher than the dielectric constant of the surrounding dielectric layer.

According to the third aspect, a high capacitance value can be obtained by miniaturization, the degree of capacitive coupling between each line and the terminal is reduced, and the original capacitive coupling between the respective layers can be easily obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a laminated structure showing an embodiment of a laminated filter according to the present invention, and FIGS.
(G) is a plan view of each layer, FIGS. 3 (A) and 3 (B) are external views and equivalent circuit diagrams, respectively, and FIGS. 4 (A) to 4 (C) are plan views showing overlapping of the lines. Is a sectional view thereof.

In FIGS. 1, 2, 4 and 5, 1a to 1a
1i is an insulating layer made of a dielectric, 3a to 3c are signal lines, 2a to 2d are ground lines alternately facing the signal lines 3a to 3c in the stacking direction, 4a to 4c, 5a
5c are ground lines provided on both sides of the same layer as the signal lines 3a-3c of each layer.

Each of the lines 2a-2d, 3a-3c, 4
a to 4c, 5a to 5c are linear, and the signal lines 3a to
Connection protrusions d and e are formed on both sides of the ground lines 2a to 2d facing the stacking direction with respect to 3c, respectively, and one protrusion d is provided with a via hole 6a provided in each of the insulator layers 1b to 1g. The ground lines 4a to 4c are connected through 6c, 6e, 6g, 6i, and 6k, and the ground lines 2a to 2d are connected to each other.

The other protruding portion e is formed of each of the insulator layers 1b to 1g.
Via holes 6b, 6d, 6f, 6h, 6
j, 6m are connected to the ground lines 5a to 5c, and the ground lines 2a to 2d are connected to each other.

One end of the signal line 3a is connected to one end of the upper signal line 3b via via holes 7a and 7b provided in the insulator layers 1c and 1d, respectively. It is connected to one end of a signal line 3c thereover via via holes 7c and 7d provided in the insulator layers 1e and 1f.

In the manufacture, the insulator layers 1a to 1i are realized as dielectric green sheets containing, for example, alumina and glass or layers formed in a film shape by screen printing, and the ground lines 2a to 2d and the signal lines 3 are formed.
a to 3c are realized by printing a layer of a conductive paste such as silver or silver-palladium on the insulator layers 1a to 1i, and the via holes 6a to 6m are realized by filling the paste into the via holes 6a to 6m. Is done.

Green sheets on which a large number of these conductor patterns are formed are laminated, cut into chips, fired, and then, as shown in FIG. 3A, the base 1 obtained as described above. It is manufactured by providing input terminals 8, output terminals 9 at both ends and ground terminals 10, 10 at both sides by baking and plating on the outer surface. Both ends k and m of the ground line 2a in FIGS.
0, the end o of the signal line 3a is connected to the input terminal 8, and the end n of the signal line 3c is connected to the output terminal 9.

As can be seen from FIG. 4, the ground line 2
By alternately arranging the signal lines a to 2d and the signal lines 3a to 3c, they oppose each other with an insulator layer interposed therebetween, thereby forming a capacitor in an opposing area z indicated by oblique lines. Also,
Ground lines 4a to 4c are provided on both sides of each signal line 3a to 3c.
4c, 5a to 5c face each other in the same layer,
Construct a capacitor.

As shown in FIG. 3B, the multilayer filter has ground lines 2a-2d, 4a-4c, 5a
To 5c constitute a coil 11, and the signal lines 3a to 3c
A coil 3 is formed by 3c, and a capacitor 12 is formed between them by opposing each other.

According to the multilayer filter having such a structure, a multilayer filter having a large attenuation in a high frequency band exceeding 1 GHz can be obtained as compared with the multilayer filter having the conventional structure.

As described above, since the signal lines 3a to 3c and the ground lines 2a to 2d, 4a to 4c, and 5a to 5c are formed linearly, for example, the pattern of the signal lines 3a to 3c is not changed and the ground lines are not changed. Lines 2a-2d, 4a
By changing the length of any one of 〜4c, 5a〜5c, the capacitance can be changed, and thereby the filter characteristics can be changed. Therefore, the target filter characteristics can be easily obtained. In particular, the capacitance can be finely adjusted by changing the length of at least one of the ground lines 4a to 4c or 5a to 5c on both sides having a small area facing the signal lines 3a to 3c.

Also, since the ground lines 4a to 4c and 5a to 5c are provided in the same layer as the signal lines 3a to 3c, the capacitance value is larger than when the signal lines and the ground lines are simply opposed in the stacking direction. Is obtained, and a multilayer filter having a large attenuation is obtained. In addition, the signal lines 3a to 3a
3c is the ground line 2a-2d, 4a-4c, 5a-
5c, noise is generated by the signal line 3a.
3c is prevented, and a noise reduction effect is obtained.

In the present invention, a configuration may be adopted in which only one of the ground lines 4a to 4c and 5a to 5c on both sides of the signal lines 3a to 3c is provided. However, ground lines 4a to 4c are provided on both sides of these signal lines 3a to 3c.
And 5a to 5c, the signal line 3
The influence of external noise on a to 3c can be reduced more effectively.

FIG. 6 is a sectional view showing another embodiment of the present invention, and FIG. 7 is a sectional view thereof. In the present embodiment, the signal lines 3a-3c and the ground lines 2a-2
The dielectric constants of the dielectric layers 13a to 13f interposed in a portion facing the portion d are higher than the dielectric constants of the surrounding insulator layers 1a to 1g. Specifically, for example, the insulator layers 1a to 1a
1i is made to have a dielectric constant of, for example, about 4 to 11 by the mixture of alumina and glass, while the dielectric layers 13a to 13i are made.
For 13f, the dielectric constant is increased to, for example, about 20 to 100 by mixing titanium oxide with alumina and glass.

According to the examples of FIGS. 6 and 7, the signal line 3a
By increasing the dielectric constant of the dielectrics 13a to 13f at the opposing portions between the ground lines 2a to 2d, a high capacitance value can be obtained and the size of the multilayer filter can be further reduced. Moreover, each line 2a-2d, 3a-
Since the degree of capacitive coupling between the terminal 3c and the terminals 8 to 10 can be reduced, the original capacitive coupling between the respective layers can be easily obtained, and the original attenuation characteristics can be easily obtained.

FIG. 8 is a sectional view showing another embodiment of the present invention. In the present embodiment, not only is the dielectric layer 13 having a high dielectric constant provided between the signal lines 3a to 3c and the ground lines 2a to 2d facing each other in the stacking direction,
The dielectric layer 14 having a high dielectric constant is provided between the signal lines 3a to 3c and the ground lines 4a to 4c and 5a to 5c provided in the same layer. According to the present embodiment,
Higher capacitance is obtained, and further miniaturization is achieved. It should be noted that the opposing signal line 3a in the same layer
3C and the ground lines 4a-4c and 5a-5c, the above effect can be achieved even if the high dielectric layer 14 is provided.

[0025]

According to the first aspect, the signal lines and the ground lines are alternately arranged in the stacking direction via the dielectric layers, respectively, and the ground lines and the ground lines are respectively arranged in the same layer as the signal lines of the respective layers. Since another ground line is provided, the capacitance can be changed by changing the length of the ground line or the distance from the signal line, so that the desired filter characteristics can be easily obtained. In particular, by changing the length of the ground line facing the same layer as the signal line or the distance to the signal line, the capacitance can be minutely changed and the filter characteristics can be finely changed.

Further, since the ground line is also provided on the same layer as the signal line, a large capacitance value can be obtained as compared with a case where the signal line and the ground line are simply opposed in the stacking direction, and the stacked type having a large attenuation can be obtained. A filter is obtained. Further, since the signal line is surrounded by the ground line, noise is prevented from entering the signal line, and a noise reduction effect is obtained.

According to the second aspect, in addition to the first aspect, the ground lines provided on the same layer as the signal lines of the respective layers are provided on both sides of the signal lines of the respective layers. A higher capacitance can be obtained as compared with the case where a ground line is provided on one side of the. Also,
By changing the length or the like of the ground line on both sides of the same layer of the signal line, the adjustment range of the capacitance can be expanded, and the change range of the filter characteristic can be expanded.

According to the third aspect, in addition to the first and second aspects,
Since the dielectric constant of the dielectric layer interposed in at least one of the direction in which the signal line and the ground line are stacked or facing each other in the same layer is higher than the dielectric constant of the surrounding dielectric layer, the size is high due to miniaturization. The capacitance value can be obtained, and the effect of reducing the degree of capacitive coupling between each line and the terminal can be further obtained, so that the original capacitive coupling between the layers can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a laminated structure of an embodiment of a laminated filter according to the present invention.

FIGS. 2A to 2G are plan views of respective layers of the multilayer filter of FIG.

FIGS. 3A and 3B are an external view and an equivalent circuit diagram of the multilayer filter of the present embodiment, respectively.

FIGS. 4A to 4C are plan views showing overlapping lines of the multilayer filter of the present embodiment.

FIG. 5 is a cross-sectional view showing the multilayer filter of the present embodiment.

FIG. 6 is a diagram showing a laminated structure of another embodiment of the laminated filter according to the present invention.

FIG. 7 is a sectional view showing the multilayer filter of the embodiment shown in FIG. 6;

FIG. 8 is a sectional view showing another embodiment of the multilayer filter according to the present invention.

FIGS. 9A and 9B are a laminated structure diagram and an equivalent circuit diagram of a conventional laminated filter, respectively.

[Explanation of symbols]

1: base, 1a-1i: insulator layer, 2a-2d, 4a-
4c, 5a to 5c: ground line, 3, 11: coil, 3a to 3c: signal line, 6a to 6m, 7a to 7
d: via hole, 8: input terminal, 9: output terminal, 10:
Ground terminal, 12: capacitor, 13, 13a to 13f,
14: High dielectric constant layer

Claims (3)

[Claims] 1. A signal line and a ground line are alternately arranged via a dielectric layer in a laminating direction, and a ground line different from the ground line is provided on the same layer as the signal line of each layer. The signal lines of the respective layers are connected to each other, and both ends thereof are connected to input terminals and output terminals on the outer surface of the base, and the ground lines are connected to each other, and only one end of the ground line is connected to the ground terminal on the outer surface of the base. A stacked filter characterized by the following. 2. The multilayer filter according to claim 1, wherein ground lines provided on the same layer as the signal lines of the respective layers are provided on both sides of the signal lines of the respective layers. 3. The dielectric constant of a dielectric layer according to claim 1, wherein the signal line and the ground line face each other in the stacking direction or at least one of opposing portions in the same layer. Is higher than the dielectric constant of the surrounding dielectric layer.