JPH06244612A - Manufacture of laminated dielectric filter - Google Patents

Abstract

PURPOSE:To efficiently manufacture a laminated dielectric filter according to a many number taking system and to stabilize quality/characteristics by eliminating assembly deviation among respective members. CONSTITUTION:A resonator substrate is manufactured by laminating/adhering a lot of dielectric substrates, for which electrodes are formed on the main surfaces, and cutting the laminated body vertically to the main surfaces. Plural resonator substrates 36a and 36b are laminated with a substrate 40 for coupling adjustment in between and integrally structured by arranging, outside substrates 42a and 42b. Then, it is cut and separated in parallel to an internal electrode 38 so as to intermediately position the internal electrode as a filter element body, and an electrode is formed on the outer surface. One part 44 of the external electrode and an input/output electrode 46 are previously formed on the outside main surface of the outside substrate, and it is preferable to form any electrode required for the remaining outer surface (four faces) of the filter element body later.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a laminated dielectric filter having a 1/4 wavelength resonance type strip line. More specifically, the multi-cavity resonator substrate, the coupling adjustment substrate, and the outer substrate are laminated and adhered, and then cut and separated, and electrodes are provided on the outer surface. The present invention relates to a method for manufacturing a laminated dielectric filter which is intended to stabilize the above. This dielectric filter is suitable for various types of radio equipment for microwaves, for example.

[0002]

2. Description of the Related Art As a microwave filter, there is a type in which a resonator is composed of a strip line. For example, in the case of a quarter-wave resonator, a linear stripline resonator conductor is provided on a dielectric substrate, one end of which is open and the other end is short-circuited to an external electrode. Here, the resonator conductor is set to have a length that is an odd multiple of a quarter wavelength of the resonance wavelength.
When constructing an actual filter, a plurality of the above-mentioned resonator conductors are arranged on the dielectric substrate and the short-circuit surfaces are commonly connected, and the distance between the adjacent resonator conductors is a predetermined value that provides a coupling strength corresponding to the filter characteristics. Set to distance.

In such a strip line type filter, for example, a conductive paste is attached on a dielectric substrate in a predetermined shape by screen printing, or an electrode forming portion is formed on the surface of the dielectric substrate so as to have a predetermined shape. A process of making it slightly depressed is performed, and the inside is filled with a conductive paste. After that, the dielectric substrate is heat-treated to bake the conductive paste to form a desired electrode pattern. As another example, there is also a tri-plate structure in which a thin conductive plate (resonator conductor) which is previously formed into a predetermined shape by punching or etching is sandwiched between two dielectric substrates.

[0004]

In any of these conventional stripline filters, the resonator conductor is formed in a plane on the same dielectric substrate, and the band of the filter is the resonator conductor. Since it is determined by the coupling state due to the spacing, it is difficult to control to a desired band, especially when the filter is miniaturized.

The formation of the resonator pattern by the screen printing method generally cannot be said to have sufficient printing accuracy, and the resonance frequency and the coupling change, so that trimming is necessary. Further, when forming a concave portion on the dielectric substrate and filling the conductive material with the conductive material, the conductive material adheres to unnecessary portions as well, so that it must be removed and complicated work is required. Further, in the case of the triplate structure, the presence of the conductive plate causes a gap between the two dielectric substrates by the thickness of the conductive plate, so that the equivalent dielectric constant is lowered and the size cannot be reduced so much. In addition, it is necessary to take measures to shield the thickness of the conductive plate. When the dielectric substrates are superposed, a dimensional deviation is likely to occur, and it is difficult to obtain desired characteristics.

To solve these drawbacks, the present inventors previously proposed a laminated dielectric filter (for example, Japanese Patent Application No. 4-158578). Here, it is manufactured by stacking a plurality of resonators each having a strip line inside with a coupling adjustment member between them, providing outer members on both sides in the stacking direction, and forming external electrodes on the outer surface. is doing.

It is an object of the present invention to efficiently manufacture a multi-layer dielectric filter having the above-mentioned structure by a multi-cavity manufacturing method, and to eliminate assembly misalignment between members to stabilize quality and characteristics. It is to provide a manufacturing method.

[0008]

According to the present invention, a large number of dielectric substrates, each having an electrode serving as an internal electrode of a stripline resonator formed on a main surface thereof, are laminated and adhered, and the laminated body is attached to the main surface. A step of vertically cutting a plurality of resonator substrates, and stacking a plurality of the resonator substrates with a coupling adjustment substrate sandwiched therebetween, and further stacking the resonator substrates on both sides in the stacking direction. An outer substrate is arranged on the outer side to be bonded and integrated, and the integrated structure is cut and separated so that the inner electrode is parallel to the inner electrode and the inner electrode is located in the middle, and an electrode is formed on the outer surface of the separated filter body. The method for manufacturing a laminated dielectric filter, comprising:

Here, a part of the external electrodes and the input / output electrodes are previously formed on the outer main surface of the outer substrate, an integrated structure is produced using the outer substrate with electrodes, and the separated filter element body is formed. It is preferable to form a necessary electrode (an island-shaped electrode that is electrically connected to the rest of the external electrode and the input / output electrode) on the remaining outer surface (four surfaces) of the above. Alternatively, a method may be used in which an integrated structure is manufactured using an outer substrate without electrodes, and then necessary electrodes are formed on the entire outer surfaces (6 surfaces) of the separated filter body. The resonator substrate is used in a number corresponding to the required number of filter stages, and these are stacked to assemble a filter.

[0010]

In the step of producing a resonator substrate, the laminated body is cut, so that a large number of substrates of the same shape in which a large number of resonators are aligned in the lateral direction and integrated are obtained. The precision of the internal electrodes of the resonator is determined by the precision of the cutting process and is sufficiently high and stable. In the next step, since the resonator substrates are stacked via the coupling adjustment substrate, the members originally cut from the same dielectric substrate are stacked, and the positional deviation of the overlapping resonators is It does not occur at any position on the resonator substrate (either near the edge or near the center). This makes it possible to easily obtain a large number of laminated dielectric filters having uniform characteristics.

[0011]

1 to 6 show each step of an example of a method for manufacturing a laminated dielectric filter according to the present invention. This is 2
This is the case of a stage filter. As shown in FIG. 6, the laminated dielectric filter obtained by this manufacturing method has two quarter-wave resonator stripline type resonators 10a and 10b.
And one coupling adjusting member 12 are alternately laminated in the thickness direction, outside members 14a and 14b are arranged on the outside thereof, and necessary electrodes such as input / output electrodes and external electrodes are formed on their outer surfaces. Is.

The manufacturing process is as follows. First, Fig. 1
And as shown in FIG. 2, a resonator substrate is produced. As shown in FIG. 1, an electrode 32 is formed on the main surface of the dielectric substrate 30, and a large number of these are laminated and bonded. The dielectric substrate 30 is a material of the resonator, and is a sintered body of a microwave high dielectric constant material such as barium titanate, which is usually used for microwave filters. A silver paste is applied to the entire main surface of a flat plate-shaped dielectric substrate 30 having a predetermined thickness to form a baking electrode 32 (this electrode 32).
Is the internal electrode of the stripline resonator). A silver paste for adhesion is applied to this, and a large number of them are laminated, pressed together, and baked to form a laminated body 34.

Next, as indicated by phantom lines, each dielectric substrate 3
2. The resonator substrate 3 as shown in FIG. 2 is thinly sliced at a predetermined thickness (resonator width dimension) perpendicularly to the main surface of 0.
Get 6. Therefore, each resonator substrate 36 has an internal electrode 38.
A large number of resonators provided with are aligned in the lateral direction and are integrally coupled.

Among the resonator substrates 36 thus obtained, as shown in FIG. 3, two resonator substrates 36a, 36 are provided.
b is laminated with the coupling adjusting substrate 40 sandwiched therebetween, and the outer substrates 42a and 42b are arranged on both sides in the laminating direction, and integrated with an adhesive such as glass. At this time, it goes without saying that both the resonator substrates 36a and 36b are laminated so as to be aligned so that the corresponding internal electrodes 38 are located in the same plane. Coupling adjustment substrate 40 and outer substrates 42a, 42b
Is not necessarily the same as the material of the dielectric substrate 30 (dielectric material forming the resonator). A material having a dielectric constant lower than that of the resonator material (for example, forsterite) may be used.

In this embodiment, the outer substrates 42a, 42b
An electrode pattern composed of a part 44 of the external electrode and the input / output electrode 46 is previously formed on the outer main surface of the. Although not shown, the input / output electrodes 46 of the one outer substrate 42a and the other outer substrate 42b are in opposite positions (in the figure, the input / output electrodes of the outer substrate 42a are on the front side, and the input / output electrodes of the outer substrate 42b are It is formed on the back side). As shown in FIG. 4, the integrated structure 50 laminated by using the outer substrates 42a and 42b with electrode patterns is cut and separated at positions indicated by imaginary lines. The cutting position (cut surface) is the resonator substrate 36.
parallel to the internal electrodes 38 of a and 36b, and the internal electrodes 38
Is a surface located in the middle. In addition, in order to adjust the shape, the entire circumference of the integrated structure 50 is cut off as shown by an imaginary line. As a result, the filter element body 5 as shown in FIG.
2 is obtained. In the step of cutting and separating, the electrode patterns on the outer main surfaces of the outer substrates 42a and 42b have a shape in which the part 44 of the external electrode and the input / output electrode 46 are separated.

Outer surfaces (four sides) of the filter element body 52
Then, as shown in FIG. 6, the remaining portion 45 of the external electrode and the island-shaped electrode 48 are formed by metallization. Remaining part of external electrode 4
5 is electrically connected to the part 44 of the external electrode described above, and the island-shaped electrode 48 is provided at the resonator part and electrically connected to the input / output electrode 46. In this way, the laminated dielectric filter 60 is obtained. 6A and 6B show a state viewed from the surfaces opposite to each other.

The structure of the produced laminated dielectric filter 60 is as follows. Two 1/4 wavelength resonance strip line type resonators 10a and 10b are combined into one coupling adjusting member 1.
2, and the outer members 14a and 14b are provided on the outer side thereof.
Are arranged, and necessary electrodes are formed on their outer surfaces. Both resonators 10a and 10b have the same shape, and the end surface on the electrodeless side is an open surface and the end surface on the electrode forming side is a short circuit surface. Here, the directions of the resonators 10a and 10b (positions of the open surface and the short-circuit surface) are set exactly opposite to each other. Then, the independent island-shaped electrode 48 is located on the outer surface near the electrodeless end surface. Note that, in order to make the drawings easy to understand, a shadow line is drawn in each drawing, and a non-electrode portion (a portion where the base material of the dielectric is exposed) is shown with fine dots.

In the strip line type resonator as described above, a quarter wavelength resonator is formed by an internal electrode formed in a dielectric material, and is shorted by an external electrode. Therefore, the resonance wavelength (resonance frequency) is basically determined by the length dimension of the resonator. Further, the larger the width (dimension in the stacking direction) of the resonator, the lower the resonance frequency, and the smaller the height (interval between the inner electrode and the outer electrode), the lower the resonance frequency. The resonance frequency of the resonator can be finely adjusted by trimming its external electrodes. The input / output coupling is performed by the capacitance between the internal electrode of the resonator and the island electrode. Therefore, by trimming the island electrodes,
I / O coupling can be fine-tuned. In this embodiment, the input / output electrodes are formed on the outer member, but the capacitance of this input / output electrode portion is not significantly affected. With this input / output electrode, the soldering portion (fillet) can be visually confirmed at the time of surface mounting, the reliability of mounting can be enhanced, and the work can be facilitated.

In each resonator, the coupling adjustment member between the resonators adjusts the coupling between the stages, thereby realizing a desired filter. This is shown in FIGS. 7 and 8. Figure 7
When the width (dimension in the stacking direction) of the coupling adjusting member is set to 1 mm, the relative bandwidth (ΔB _T / f) to the dielectric constant εr of the material
₀ ) shows the relationship. Further, FIG. 8 shows the relationship between the width and the specific bandwidth, using a material having a dielectric constant εr of 7 as the coupling adjusting member. As described above, it is understood that the degree of coupling can be easily controlled and the specific bandwidth can be adjusted by changing the material (dielectric constant) or the size of the coupling adjusting member.

In the laminated dielectric filter of this embodiment, since the input and output electrodes are located diagonally and are separated from each other, radio wave skipping between the input and output can be reduced, and as a result, the metal case is not always required. You don't have to cover it. As described above, this filter can be directly surface-mounted on the circuit board. On the circuit board, the input / output electrodes are connected to the input / output pattern of the circuit board, and the external electrodes are soldered to the ground pattern of the circuit board for electrical connection and mechanical fixing. Of course, you may cover with a metal case.

The preferred embodiment of the present invention has been described above in detail, but the present invention is not limited to this configuration. The present invention can be applied to a filter having three or more stages.
In that case, a required number of resonator substrates may be stacked with a coupling adjustment substrate interposed therebetween. The position of the input / output electrodes and the orientation of the resonator can be set freely. In addition, in the above-mentioned embodiment, although a part of the external electrodes and the input / output electrodes are formed on the outer substrate in advance, an integrated structure is produced using the electrodeless outer substrate, and the separated filter elements are Outer surface (6 sides)
The electrodes required for the above may be formed. However, workability is better if electrodes are formed on the outer substrate in advance.

[0022]

As described above, the present invention obtains a large number of resonator substrates by laminating and slicing a large number of dielectric substrates with electrodes interposed therebetween, and the resonator substrates are interposed with a substrate for adjusting coupling therebetween. Since the outer substrates are provided on both sides and laminated, and the substrates are cut to form a filter element body and external electrodes and the like are provided, a laminated dielectric filter can be efficiently manufactured by a multi-piece manufacturing method. Further, since the resonator substrates having the same shape can be obtained, it is possible to eliminate assembly deviation between the respective members (in particular, positional deviation between the resonators at the time of stacking), and the quality and characteristics are stabilized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a manufacturing process of a resonator substrate.

FIG. 2 is a perspective view of a resonator substrate.

FIG. 3 is an explanatory diagram of a stacked state of a resonator substrate, a coupling adjustment substrate, and an outer substrate.

FIG. 4 is an explanatory view showing an integrated structure and a cutting position.

FIG. 5 is a perspective view of a filter element body.

FIG. 6 is a perspective view of a laminated dielectric filter.

FIG. 7 is a graph showing the relationship between the dielectric constant and the specific bandwidth of the coupling adjusting member.

FIG. 8 is a graph showing the relationship between the thickness of the coupling adjusting member member and the specific bandwidth.

[Explanation of symbols]

 30 Dielectric Substrate 32 Electrode 34 Laminates 36, 36a, 36b Resonator Substrate 38 Internal Electrode 40 Coupling Adjustment Substrates 42a, 42b Outer Substrate 44 Part of External Electrode 45 Remaining External Electrode 46 Input / Output Electrode 48 Island-like Electrode 50 Integrated structure 52 Filter element 60 Laminated dielectric filter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location H01P 7/08 (72) Inventor Masaki Ina 5-3-11 Shinbashi, Minato-ku, Tokyo Fuji Electric Chemical Incorporated (72) Inventor Teruno Kanno 5-36-1 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd.

Claims (2)

[Claims] 1. A plurality of resonances are formed by laminating a plurality of dielectric substrates, each having an electrode serving as an internal electrode of a stripline resonator formed on a main surface thereof, and laminating the laminated body perpendicularly to the main surface. A step of producing a resonator substrate, and stacking a plurality of the resonator substrates with a coupling adjustment substrate sandwiched therebetween, and disposing outer substrates further outside the resonator substrates located on both sides in the stacking direction. Adhesively integrating, cutting the integrated structure so that the internal electrode is parallel to the internal electrode and the internal electrode is located in the middle, and forming an electrode on the outer surface of the separated filter body. Method of manufacturing laminated dielectric filter. 2. A filter element body in which a part of external electrodes and input / output electrodes are formed in advance on the outer main surface of the outer substrate, and an integrated structure is produced using the outer substrate with electrodes, and separated. 2. The method for manufacturing a laminated dielectric filter according to claim 1, wherein the remaining external electrodes and island-shaped electrodes that are electrically connected to the input / output electrodes are formed on the remaining four outer surfaces.