JP2002319802A - Laminated dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated dielectric filter in which dispersion in the characteristic is less. SOLUTION: Since capacitance forming electrodes 122, 123 150 and 151 to sufficiently increase the capacitance caused between the ground electrodes 121 and 149 more than the capacitance caused between a ground electrode 121 and 149 and a sneaked path part of an input terminal (output terminal) are positioned, dispersion in the characteristic caused by the manufacturing accuracy of the sneaked path part of the input terminal (output terminal) can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated dielectric filter suitable for a high-frequency circuit.

[0002]

2. Description of the Related Art A conventional laminated dielectric filter will be described with reference to FIGS. FIG. 15 is an external perspective view of a conventional laminated dielectric filter, and FIG. 16 is a cross-sectional view of the laminated filter cut along a ground electrode forming layer.

As shown in FIG. 15, a conventional laminated dielectric filter 10 includes a laminated body 11 formed by laminating a dielectric and a conductor, and a pair of input / output terminals 12 attached to both ends of the laminated body 11. And a ground terminal 1 formed on the outer surface of the laminate 11
3 is provided.

The input / output terminals 12 are formed linearly at the center of both end faces 11a parallel to the stacking direction of the stacked body 11 and at the ends of upper and lower surfaces 11b orthogonal to the stacking direction.
The ground terminal 13 is formed from the entire surface of the side surface 11c parallel to the stacking direction of the stacked body 11 to the end surface 11a and the end of the upper and lower surfaces 11b.

The laminated body 11 includes a resonance element and a ground electrode 1.
4 and a dielectric. Here, the ground electrode 14 is disposed in a layer near the upper and lower surfaces 11 b of the multilayer body 11. Further, the resonance element is disposed in the middle layer of the multilayer body 11 so as to be sandwiched between the pair of ground electrodes 14 via the dielectric.

[0006] As shown in FIG. 16, the ground electrode 14 is connected to the ground terminal 13. Further, the ground electrode 14 has a shape in which a side facing the surface on which the input / output terminal 12 is formed is drawn inward.

A method for manufacturing the laminated dielectric filter 10 will be described. First, a conductive paste for forming a resonance element, a ground electrode, and the like is printed on a green sheet. Next, the green sheets are laminated in a predetermined order.
Crimping is performed to obtain a sheet laminate. Next, the sheet laminate is cut into unit parts to obtain a laminated chip. Next, the laminated chip is fired at a predetermined temperature to obtain the laminated body 10. Next, a conductive paste for forming the input / output terminals 12 and the ground terminals 13 is applied to the outer surface of the laminate 10. Next, the laminated body 10 is fired to obtain the laminated dielectric filter 10.

[0008]

However, it is difficult for the conventional laminated dielectric filter 10 to stabilize various characteristics such as frequency specification. One of the factors is the application accuracy of the conductive paste for the input / output terminals 12. The relationship between the application accuracy of the conductive paste and the stability of the frequency characteristics will be described below.

Generally, a transfer method or the like is used for applying the conductive paste for the input / output terminals 12. In the transfer method,
First, a groove is provided on the surface of an elastic body such as silicon rubber, and the groove is filled with a conductive paste. Then, the conductive paste is attached by pressing the side surface 11a of the laminate 11 against the elastic body. In such a coating method, FIG.
As shown in FIG. 7, the conductive paste wraps around and adheres to not only the side surface 11a of the laminate 11 but also the adjacent upper and lower surfaces 11b. Here, the accuracy of the wraparound length is affected by the immersion distance of the laminate in the conductive paste, the pressing force on the elastic body, the viscosity of the conductive paste, the hardness of the elastic body, and the like. There are limits to improvement.

On the other hand, as shown in FIG.
2 is connected to the ground electrode 1 via a dielectric.
4. Therefore, a stray capacitance is formed between the wraparound portion 12a and the ground electrode 14. The value of the stray capacitance depends on the wraparound length of the wraparound portion 12a.
However, as described above, it is difficult to control the wraparound length of the wraparound portion 12a with high accuracy. For this reason,
The value of the stray capacitance of each laminated dielectric filter 10 is not stable. On the other hand, the fluctuation of the stray capacitance greatly affects various characteristics of the laminated dielectric filter 10. In particular, the stray capacitance greatly affects various characteristics in a high frequency region.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated dielectric filter having less variation in characteristics.

[0012]

In order to achieve the above object, according to the present invention, a laminated body in which a dielectric and a conductor are laminated, an input / output terminal and a ground terminal formed on the outer surface of the laminated body are provided. Wherein the input / output terminal is adjacent to the main portion formed on one outer surface parallel to the laminating direction of the laminate and is orthogonal to the laminating direction. A wraparound part wrapped around another outer surface, wherein the laminate is formed so as not to overlap with the wraparound part of the input / output terminal via a dielectric layer, and a ground electrode connected to the ground terminal; A capacitance forming electrode connected to the input / output terminal and having a capacitance generated between the wraparound portion of the input / output terminal and the ground electrode, which is sufficiently larger than a capacitance generated between the wraparound portion of the input / output terminal and the ground electrode. Things To draft.

According to the present invention, the stray capacitance between the input / output terminal and the ground electrode is the capacitance generated between the capacitance forming electrode and the ground electrode, and the capacitance generated between the wraparound portion of the input / output terminal and the ground electrode. Is a combined capacitance connected in parallel. Here, the capacitance generated between the capacitance forming electrode and the ground electrode is sufficiently larger than the capacitance generated between the wraparound portion of the input / output terminal and the ground electrode. Therefore, even if the capacitance generated between the wraparound portion of the input / output terminal and the ground electrode fluctuates, the fluctuation of the stray capacitance between the input / output terminal and the ground electrode becomes negligibly small. On the other hand, the fluctuation of the stray capacitance between the input / output terminal and the ground electrode is affected by the fluctuation of the capacitance between the capacitance forming electrode and the ground electrode. This capacitance is determined by the shape of the capacitance forming electrode, the distance from the ground electrode, and the like. The shape of the capacitance forming electrode, the distance to the ground electrode, and the like can be controlled with higher precision than the length of the wraparound portion of the input / output terminal. Generally, the accuracy of the former and the accuracy of the latter have an order of magnitude of one digit or more. Therefore, in the laminated dielectric filter according to the present invention, the value of the stray capacitance can be controlled with high accuracy, and thus, variation in characteristics can be suppressed.

As an example of a preferred mode of the present embodiment,
According to a second aspect, in the multilayer dielectric filter according to the first aspect, the capacitance generated between the capacitance forming electrode and the ground electrode is two times the capacitance generated between the wraparound portion of the input / output terminal and the ground electrode. We propose something that is more than double. In claim 3, claim 1 or 2
2. The multilayer dielectric filter according to claim 1, wherein the capacitance forming electrode is formed in the same layer as a ground electrode. According to a fourth aspect of the present invention, in the laminated dielectric according to any one of the first to third aspects, the wraparound portion of the input / output terminal overlaps a part of the capacitance forming electrode via a dielectric layer. I suggest something.

According to a fifth aspect of the present invention, there is provided a laminated dielectric filter comprising a laminate in which a dielectric and a conductor are laminated, and an input / output terminal and a ground terminal formed on an outer surface of the laminate. The output terminal includes a main portion formed on one outer surface parallel to the laminating direction of the laminate and a wraparound portion adjacent to the outer surface and wrapping around to another outer surface orthogonal to the laminating direction. The laminate includes a wraparound portion of the input / output terminal and a ground electrode formed so as not to overlap with a dielectric layer interposed therebetween, and a ground electrode connected to the ground terminal. It is proposed that the distance between the main part of the terminal and the side of the ground electrode facing the main part be 50% or less.

According to the present invention, the capacitance generated between the wraparound portion of the ground terminal and the ground electrode can be reduced. Therefore, it is possible to suppress variations in characteristics regardless of the formation accuracy of the ground terminal.

According to a sixth aspect of the present invention, there is provided the multilayer dielectric filter according to the fifth aspect, further comprising a characteristic measuring terminal formed integrally with the wraparound portion on an outer surface facing the mounting destination during mounting. I suggest something.

In the laminated dielectric filter according to the fifth aspect, the area of the wraparound portion of the input / output terminal is smaller than that of the conventional one. This wraparound portion is not particularly required for mounting, but is required for measuring characteristics. According to the present invention, since the characteristic measuring terminal formed integrally with the wraparound portion is provided, characteristic measurement can be easily performed.

According to a seventh aspect of the present invention, in the laminated dielectric filter according to the sixth aspect, the width of the characteristic measuring terminal is smaller than the width of the input / output terminal. Suggest what to do. According to claim 8, in the multilayer dielectric filter according to any one of claims 6 and 7, the characteristic measurement terminal is formed so as not to overlap with the ground electrode via a dielectric layer. We propose the one that features.

[0020]

(First Embodiment) A laminated dielectric filter according to an embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG. 1 is an external perspective view of a multilayer dielectric filter, FIG. 2 is a diagram illustrating a multilayer structure of the multilayer dielectric filter, and FIG. 3 is a cross-sectional view of the multilayer dielectric filter taken along line AA ′ in FIG. 4 is a cross-sectional view of the multilayer dielectric filter taken along line BB 'in FIG. 2, FIG. 5 is a cross-sectional view of the multilayer filter cut by a ground electrode forming layer, FIG. 6 is an equivalent circuit diagram of the multilayer dielectric filter, FIG. 7 is an enlarged sectional view of a portion C in FIG. 4 of the laminated dielectric filter.

As shown in FIG. 1, this laminated dielectric filter 100 is composed of a laminated body 10 formed by laminating a dielectric and a conductor.
1, a pair of input / output terminals 102 attached to both ends of the multilayer body 101, and a ground terminal 103 formed on the outer surface of the multilayer body 101.

The input / output terminal 102 has a main portion 102a extending in the laminating direction at the center of both end surfaces 101a parallel to the laminating direction of the laminated body 101, and an upper and lower surface 101b perpendicular to the laminating direction from the end surface 101a. And a wraparound portion 102b formed by wraparound.

The ground terminal 103 is formed from the entire side surface 101c parallel to the laminating direction of the laminated body 101 to the end surface 101a and the ends of the upper and lower surfaces 101b. That is, the ground terminal 103 is formed on the main portion 103a formed on the entire surface of the side surface 101c parallel to the stacking direction of the stacked body 101.
And the end face 101a and the upper and lower faces 101 from the side face 101c.
and a wraparound portion 103b formed so as to wrap around the end of b.

As shown in FIG. 2 to FIG.
Has an integrated structure in which a dielectric layer 110 on which no conductor is formed and a plurality of dielectric layers 111 to 119 on which conductors of a predetermined pattern are formed are laminated. Each dielectric layer 110-1
Reference numeral 19 is made of, for example, a BaTiO ₃ -based ceramic sintered body having a dielectric property.

The first ground electrode 121 is formed on the dielectric layer 111. First ground electrode 121
Are exposed on the long side of the dielectric layer 111 and are connected to the main portion 103a of the ground terminal 103. Also, the first
The ground electrode 121 is not formed at the end on the short side of the dielectric layer 111. First, when the first ground electrode 121 is formed on the entire surface of the dielectric layer 111, the bonding strength between the dielectric layer 111 and the dielectric layer 110 is reduced. Second, the ground terminal 10
3 to prevent a short circuit between the input / output terminal 3 and the input / output terminal 102.

The first ground electrode 121 has a shape in which the center of the side facing the input / output terminal 102 is drawn toward the center of the dielectric layer 111. Thus, the first ground electrode 121 does not overlap with the wraparound portion 102b of the input / output terminal 102 via the dielectric layer 110 as shown in FIG.

Further, on the dielectric layer 111, capacitance forming electrodes 122 and 123 connected to the main portion 102a of the input / output terminal 102 are formed. These capacitance forming electrodes 122 and 123 are arranged in the lead-in portion of the first ground electrode 121 described above. Thereby, the capacitance forming electrode 1
A predetermined capacitance is formed between the first and second ground electrodes 121 and 123. Further, the capacitance forming electrodes 122 and 1
23, as shown in FIG.
Are formed so as to overlap with the wraparound portion 102b of the input / output terminal 102 through the.

On the dielectric layer 112, rectangular wavelength shortening electrodes 124, 125 and 126 formed in parallel with each other are formed. The wavelength shortening electrodes 124 to 126 are
The dielectric layer 112 extends in the short direction. That is, each of the wavelength shortening electrodes 124 to 126 extends in a direction orthogonal to a direction connecting the pair of input / output terminals 102. One end of each of the wavelength shortening electrodes 124 to 126 is connected to the dielectric layer 1.
12, and is connected to the main portion 103a of the ground terminal 103. This wavelength shortening electrode 12
4 to 126 are disposed so as to overlap with first resonance element pieces 127 to 129 described later via the dielectric layer 112. Thus, the wavelength shortening electrodes 124 to 126 and the first
Since the resonance element pieces 127 to 129 are capacitively coupled, an effect of shortening the wavelength of the resonance element can be obtained.

On the dielectric layer 113, rectangular first resonance element pieces 127, 128, and 129 are formed. This first
The resonance element pieces 127 to 129 are connected to the pair of input / output terminals 1.
02 extends in a direction perpendicular to the direction connecting the two. The first resonance element pieces 127 to 129 are arranged on the dielectric layer 113 on the side where the wavelength shortening electrodes 124 to 126 are formed. Further, the first resonance element piece 127
To 129 are disposed so as to overlap with second resonance element pieces 134 to 136 described later via the dielectric layer 113.
Further, via holes 152 (see FIG. 3) are formed at one ends of the first resonance element pieces 127 to 129. The first resonance element pieces 127 to 129 are
They are connected to the second resonance element pieces 134 to 136 and the third resonance element pieces 143 to 145 via (see FIG. 3).

The coupling electrode 130 is formed on the dielectric layer 114. The coupling electrode 130 is formed on the dielectric layer 114.
Is formed so as to extend in the longitudinal direction of the dielectric layer 114 substantially in the vicinity of the center. The coupling electrode 130 has a rectangular coupling portion 130a formed at both ends and a connecting line portion 130b which connects the coupling portions 130a and has a width smaller than the coupling portion 130a.
Consists of One coupling portion 130a of the coupling electrode 130
Are arranged at positions overlapping the vicinity of the center of the first resonance element piece 127 and the second resonance element piece 134 with the dielectric layers 113 and 114 interposed therebetween. The other coupling portion 130a of the coupling electrode 130 is disposed at a position where the vicinity of the center of the first resonance element piece 128 and the second resonance element piece 135 overlaps with the dielectric layers 113 and 114 therebetween. Also, the dielectric layer 1
14, lands 131 to 133 connected to via holes 152 (see FIG. 3) of the dielectric layer 113 are formed. The via holes 152 (see FIG. 3) are formed at the positions where the lands 131 to 133 are formed.

On the dielectric layer 115, strip line type second resonance element pieces 134, 135, and 136 are formed so as to be parallel to each other. Each second resonance element piece 135
136 extend in a direction orthogonal to the direction connecting the pair of input / output terminals 102. Each of the second resonance element pieces 134 to
One end of 136 is connected to the wavelength shortening electrodes 124 to 126.
Of the ground terminal 103 on the side where is not connected
a. The other end of each of the second resonance element pieces 134 to 136 is opposed to the ground terminal 103 to which the wavelength shortening electrodes 124 to 126 are connected at a predetermined distance. The via holes 152 (see FIG. 3) are formed at the open ends of the second resonance element pieces 134 to 136.

The input / output electrodes 137 and 138 connected to the main part 102a of the input / output terminal 102 are connected to the input / output side second resonance element pieces 134 and 136 of the three second resonance elements 134 to 136. ing. Input / output electrode 137
And 138, input / output units 137a, 138a arranged at the ends of the dielectric layer 115, and the input / output units 137
a, 138a and connection lines 137b, 138b connecting the second resonance element pieces 134, 136. Connection line 1
37b and 138b are formed in a meandering linear shape,
The second resonance element piece 13 is located at a position slightly open from the center.
4,136. Note that the connection line portion 137b,
The connection position between the 138b and the second resonance element pieces 134 and 136 may be appropriately moved to the open end side or the short-circuit end side according to a filter characteristic to be a design target.

The coupling electrode 139 is formed on the dielectric layer 116. The coupling electrode 139 is formed on the dielectric layer 116.
Is formed so as to extend in the longitudinal direction of the dielectric layer 116 substantially in the vicinity of the center. The coupling electrode 139 includes a rectangular coupling portion 139a formed at both ends and a connecting line portion 139b which connects the coupling portions 139a and has a width smaller than the coupling portion 139a.
Consists of One coupling portion 139a of the coupling electrode 139
Are arranged at positions overlapping the vicinity of the center of the second resonance element piece 135 and a third resonance element piece 144 described later with the dielectric layers 115 and 116 interposed therebetween. The other coupling portion 139a of the coupling electrode 139 is located near the center of the second resonance element piece 136 and a third resonance element piece 145, which will be described later, and the dielectric layer 11.
5 and 116 are disposed at positions overlapping each other.
In the dielectric layer 116, lands 140 to 142 connected to the via holes 152 (see FIG. 3) of the dielectric layer 115 are provided.
Are formed. Via holes 152 (see FIG. 3) are formed at the positions where the lands 140 to 142 are formed.

On the dielectric layer 117, rectangular third resonance element pieces 143 to 145 are formed. The shape and arrangement of the third resonance element pieces 143 to 145 are the same as those of the first resonance element pieces 127 to 129. Third resonance element piece 143
145 are connected to via holes 152 of the dielectric layer 116 (see FIG. 3). Thereby, the first
Resonance element pieces 127 to 129, second resonance element pieces 134 to 1
36, the ends of the third resonance element pieces 143 to 145 are connected.

On the dielectric layer 118, rectangular wavelength shortening electrodes 146 to 148 formed in parallel with each other are formed. The shape and arrangement of the wavelength shortening electrodes 146 to 146 are the same as those of the wavelength shortening electrodes 124 to 126.

On the dielectric layer 119, a second ground electrode 149 and capacitance forming electrodes 150 and 151 are formed. The second ground electrode 149 has the same shape as the first ground electrode 121. Further, regarding the shape and arrangement of the capacitance forming electrodes 150 and 151, the capacitance forming electrodes 122 and 123 formed on the dielectric layer 111 are formed.
Is the same as

FIG. 6 shows an equivalent circuit of the laminated dielectric filter 100. In the figure, inductors 161 and 162
Are the connection lines 13 of the input / output electrodes 137 and 138, respectively.
7b and 138b.

The capacitor 163 is connected to the wavelength shortening electrode 12.
4 and a capacitor component generated between the first resonance element piece 127. The capacitor 164 is connected to the wavelength shortening electrode 146.
And the first resonance element piece 143. The capacitor 165 is a capacitor component generated between the wavelength shortening electrode 125 and the first resonance element piece 128. The capacitor 166 is a capacitor component generated between the wavelength shortening electrode 147 and the first resonance element piece 144. The capacitor 167 is connected to the wavelength shortening electrode 126 and the first
This is a capacitor component generated between the resonance element piece 129 and the resonance element piece 129. The capacitor 168 is connected to the wavelength shortening electrode 148 and the first
This is a capacitor component generated between the resonance element piece 145 and the resonance element piece 145.

The capacitor 169 is connected to the first resonance element piece 12.
7 and a capacitor component generated between the second resonance element piece 134 and one coupling portion 130 a of the coupling electrode 130. The inductor 170 is an inductor component generated by the connection line portion 130b of the coupling electrode 130. The capacitor 171 is a capacitor component generated between the first resonance element piece 128 and the second resonance element piece 135 and the other coupling part 130 a of the coupling electrode 130.

The capacitor 172 is connected to the second resonance element piece 13.
This is a capacitor component generated between the fifth and third resonance element pieces 144 and one coupling portion 139 a of the coupling electrode 139. The inductor 173 is an inductor component generated by the connection line portion 139b of the coupling electrode 139. The capacitor 174 is a capacitor component generated between the second resonance element piece 136 and the third resonance element piece 145 and the other coupling portion 139 a of the coupling electrode 139.

The capacitor 175 is connected to one input / output terminal 1
02 and the first ground electrode 121
And the second ground electrode 149. The capacitor 176 is connected to the capacitance forming electrode 12.
2 and 150, and a capacitor component generated between the first ground electrode 121 and the second ground electrode 149. The capacitor 177 is provided between the wraparound portion 102b of the other input / output terminal 102, the first ground electrode 121, and the second
Capacitor component generated between the ground electrode 149 and the ground electrode 149. The capacitor 178 includes the capacitance forming electrodes 123 and 1
This is a capacitor component generated between the first ground electrode 121 and the first ground electrode 121 and the second ground electrode 149.

Here, the value of the capacitor 176 is sufficiently larger than that of the capacitor 175 such that the change in the combined capacitance of the capacitor 175 and the capacitor 176 is negligible with respect to the change in the capacitor 175 (FIG. 7
reference). Similarly, capacitor 178 is
7, the capacitors 177 and 17
8 so that the change in the combined capacitance of capacitor 8 can be ignored.
This is a sufficiently large value compared to 77. The size of the capacitors 176 and 178 is preferably twice or more, more preferably ten times or more, as compared with the capacitors 175 and 177.

Further, in this laminated dielectric filter 100, as shown in this equivalent circuit, the resonance elements are composed of one resonance element pieces 127 to 129 and third resonance element pieces 143 to 145, respectively.
The second resonance element pieces 134 to 136 are connected in series to the parallel circuit.

Next, a method of manufacturing the laminated dielectric filter 100 will be described. Here, a case where a number of laminated dielectric filters are manufactured simultaneously will be described.

First, a predetermined amount of an organic binder, an organic solvent or water is mixed and stirred with a dielectric ceramic material in which, for example, BaTiO ₃ or the like is used as a main material and SiO ₂ or the like is added as an additive to obtain a ceramic slurry. Next, the ceramic slurry is formed into a ceramic green sheet by a tape molding method such as a doctor blade method.

Next, on this ceramic green sheet,
After punching with a punch or a laser if necessary, a conductive paste is printed in a predetermined shape by a screen printing method, an intaglio printing method, a relief printing method, or the like. Here, the application pattern of the conductive paste corresponds to the various electrodes and lands described above. In the present embodiment, the dimensional accuracy in this printing step was ± 0.05 mm.

Next, the ceramic green sheets are laminated and pressed by using a pressing device to obtain a sheet laminate.
Here, the lamination order of the ceramic green sheets is as shown in FIG.
And the configuration described with reference to FIG.

Next, the sheet laminate is cut into a size per component unit to obtain a laminated chip. Next, the laminated chip is fired under predetermined temperature and atmosphere conditions to obtain a laminated body 101.

Next, a conductive paste for the input / output terminals 102 is applied to the outer surface of the laminate 101 by a transfer method. Specifically, first, an elastic body such as silicon rubber having a groove corresponding to the width of the input / output terminal 102 is prepared. And
The conductive paste is filled in the grooves of the elastic body. Then
The end face 101a of the laminated body 101 is pressed against the elastic body. At this time, the elastic paste is slightly elastically deformed so that the conductive paste filled in the groove adheres to the upper and lower surfaces 101b adjacent to the end surface 101a. Thereby, a wraparound portion 102b of the input / output terminal 102 is formed. In the present embodiment, the dimensional accuracy of the wraparound portion 102b in this coating process is ±
0.2 mm.

Next, a conductive paste for the ground terminal 103 is applied to the outer surface of the laminate 101 by a dipping method.
Specifically, first, a conductive paste is applied with a predetermined thickness on the flat surface of the support base. The wraparound length of the wraparound portion 103b of the ground terminal 103 is determined by the thickness of the conductive paste. Then, the side surface 101c of the laminate 101
The side is immersed in a conductive paste on a flat surface. As a result, the conductive paste adheres not only to the side surface 101c but also to the adjacent end surface 101a and the upper and lower surfaces 101b.

Next, the laminate 101 is put into a furnace at a predetermined temperature to bake the conductive paste attached to the outer surface. Finally, the input / output terminal 102 and the ground terminal 10
3 is plated to obtain a laminated dielectric filter 100
Get.

In such a laminated dielectric filter 100, as shown in FIG. 6, a combined capacitor in which a capacitor 175 and a capacitor 176 are connected in parallel is connected before the filter circuit, and a capacitor 177 and a capacitor 1 are connected after the filter circuit.
An equivalent circuit is formed by connecting 77 combined capacitors connected in parallel. Here, as described above, the capacitors 176, 1
Since 78 is sufficiently larger than capacitors 175 and 177, the accuracy of these combined capacitances is exclusively
6,178 only affects the accuracy and the capacitors 175,1
77 is not affected.

The capacitors 176 and 178 are connected to the capacitance forming electrodes 122, 123, 150, 151 and the first
Of the first ground electrode 121 and the second ground electrode 122. On the other hand, capacitors 175 and 17
The value of 7 is affected by the accuracy of forming the wraparound portion 102b of the external electrode 102. In general, the former has higher precision than the latter by one digit or more. Therefore, in the laminated dielectric filter 100, the combined capacitance connected before and after the filter circuit is stabilized, so that variations in characteristics can be suppressed.

Although the first embodiment of the present invention has been described above, the present invention is not limited to this. The scope of the invention is indicated by the appended claims, and all modifications that fall within the meaning of each claim are included in the present invention.

For example, in the present embodiment, the capacitance forming electrodes 122, 123, 150, and 151 are provided on the same layer as the first ground electrode 121 and the second ground electrode 149, but are provided on other layers. Is also good. Further, it may be provided in a plurality of layers.

Further, the connection position and the number of connection of each resonance element piece by the via hole 152 may be appropriately changed in order to obtain desired characteristics. Thereby, since the characteristic impedance of each resonance element can be controlled, a laminated dielectric filter having desired characteristics can be obtained. For example, as shown in FIG. 8, the via hole 152 may be formed on the short-circuit side and near the center of the second resonance element. Further, as shown in FIG. 9, the via hole 152 may be formed only near the center of the second resonance element. Further, as shown in FIG. 10, a wavelength shortening electrode may not be provided. Further, FIG.
As shown in FIG. 1, each resonance element may be constituted by one resonance element piece. 8 to 11, the same elements as those in the above embodiment are denoted by the same reference numerals.

Furthermore, in the present embodiment, as shown in the equivalent circuit of FIG. 6, the connection between the equivalent circuit resonance element and the input / output terminal 102 is connected by the inductor.
You may make it connect with a capacitor. The connection circuits may be different between the input side and the output side. For example, the input side may be connected to a capacitor and the output side may be connected to an inductor.

Further, in the present embodiment, the ground terminal is formed by the dip method, but may be formed by another method such as the transfer method.

Furthermore, in the present embodiment, a configuration in which the resonance circuit has a three-stage configuration in the laminated body is illustrated, but the number may be two or four or more.

(Second Embodiment) A laminated dielectric filter according to a second embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG. FIG. 12 is an external perspective view of the multilayer dielectric filter, FIG. 13 is a top view of the multilayer dielectric filter, and FIG. 14 is a bottom view of the multilayer dielectric filter.

The multilayer dielectric filter 200 according to the present embodiment is different from the multilayer dielectric filter 1 according to the first embodiment.
The point different from 00 is that the capacitor forming electrode is not provided,
The difference lies in that the shape of the input / output terminals is different and that the input / output terminals are provided with characteristic measurement terminals. Other configurations are the same as those of the first embodiment, and therefore, only the differences will be described here.

As shown in FIG. 12, a laminated dielectric filter 200 has a laminated body 201 formed by laminating a dielectric and a conductor.
And a pair of input / output terminals 202 attached to both ends of the multilayer body 201 and a ground terminal 203 formed on the outer surface of the multilayer body 201.

The input / output terminal 202 has a main portion 202a extending in the laminating direction at the center of both end surfaces 201a parallel to the laminating direction of the laminate 201, and an upper surface 201b and a lower surface 201c perpendicular to the laminating direction from the end surface 201a. And a wraparound portion 202b formed around the portion.

The ground terminal 203 is formed from the entire surface of the side surface 201d parallel to the laminating direction of the laminated body 201 to the end surface 201a and the ends of the upper surface 201b and the lower surface 201c. That is, the ground terminal 203 is
No. 01 includes a main portion 203a formed on the entire side surface 201d parallel to the laminating direction, and a wraparound portion 203b formed to wrap around the end surface 201a and the ends of the upper surface 201b and the lower surface 201c from the side surface 201d.

As shown in FIG. 13, the wraparound portions 20 formed on the upper surface 201b and the lower surface 201c of the laminate 201 are formed.
The length L1 of 2b is a distance D between the ground electrode 210 laminated in the laminate 201 and the surface on which the input / output terminal 202 is formed.
Less than. The length L1 is preferably 50% or less of the distance D, and more preferably 20% or less. Here, the shape of the ground electrode 210 is the same as that of the first ground electrode 121 according to the first embodiment.

Further, as shown in FIG.
A characteristic measuring terminal 204 is formed integrally with the wraparound portion 202b at an end portion of the wraparound portion 202b formed on the lower surface 201c of the device. This characteristic measuring terminal 20
4 is smaller than the width of the main part 202a of the input / output terminal 202. The length L2 of the characteristic measuring terminal 204 is smaller than the distance D between the ground electrode 210 laminated in the layer body 201 and the surface on which the input / output terminal 202 is formed.

In this embodiment, when mounting the laminated dielectric filter 200, the surface facing the circuit board or the like on which the multilayer dielectric filter 200 is mounted is called the lower surface 201c, and the surface opposite to the lower surface 201c. Is referred to as an upper surface 201b.

According to such a laminated dielectric filter 200, the stray capacitance generated between the wraparound portion 202b of the input / output terminal 202 and the ground electrode 210 can be reduced, so that the accuracy of forming the input / output terminal 202 can be reduced. Irrespective of this, variations in characteristics are small. In addition, since the terminal 204 for measuring characteristics is provided, the input / output terminal 202
Despite the fact that the length of the wraparound portion 202b is significantly smaller than that of the conventional one, the characteristic test of the product can be easily and reliably performed.

Although the second embodiment of the present invention has been described above, the present invention is not limited to this. The scope of the invention is indicated by the appended claims, and all modifications that fall within the meaning of each claim are included in the present invention. Therefore, various modifications described above in the first embodiment can be similarly applied to the present embodiment.

[0070]

As described above in detail, according to the multilayer dielectric filter of the present invention, even if a slight error occurs in the formation of the input / output terminals, it is possible to suppress variations in characteristics due to the error. .

[Brief description of the drawings]

FIG. 1 is an external perspective view of a multilayer dielectric filter according to a first embodiment.

FIG. 2 is a diagram illustrating a laminated structure of the laminated dielectric filter according to the first embodiment.

FIG. 3 is a sectional view of the multilayer dielectric filter according to the first embodiment taken along line AA ′ in FIG. 2;

FIG. 4 is a cross-sectional view of the multilayer dielectric filter according to the first embodiment taken along line BB ′ in FIG. 2;

FIG. 5 is a cross-sectional view of the multilayer filter cut by a ground electrode forming layer according to the first embodiment;

FIG. 6 is an equivalent circuit diagram of the multilayer dielectric filter according to the first embodiment.

FIG. 7 is an enlarged sectional view of a portion C in FIG. 4 of the multilayer dielectric filter according to the first embodiment;

FIG. 8 is a sectional view of a multilayer dielectric filter according to another example of the first embodiment.

FIG. 9 is a sectional view of a multilayer dielectric filter according to another example of the first embodiment.

FIG. 10 is a sectional view of a multilayer dielectric filter according to another example of the first embodiment.

FIG. 11 is a sectional view of a multilayer dielectric filter according to another example of the first embodiment.

FIG. 12 is an external perspective view of a multilayer dielectric filter according to a second embodiment.

FIG. 13 is a top view of the multilayer dielectric filter according to the second embodiment.

FIG. 14 is a bottom view of the multilayer dielectric filter according to the second embodiment.

FIG. 15 is an external perspective view of a conventional laminated dielectric filter.

FIG. 16 is a cross-sectional view of a multilayer filter cut along a formation layer of a ground electrode.

[Explanation of symbols]

100, 200: laminated dielectric filter, 101, 20
1 ... laminated body, 102, 202 ... input / output terminal, 102a,
202a ... main part, 102b, 202b ... wraparound part, 1
03, 203: ground terminal, 121: first ground electrode, 122, 123, 150, 151: capacitance forming electrode, 124 to 126, 146 to 148: wavelength shortening electrode, 127 to 129: first resonance element piece , 130, 13
9: coupling electrode, 134 to 136: second resonance element piece, 1
43 to 146: third resonance element piece, 149: second ground electrode, 204: terminal for measuring characteristics, 210: ground electrode

Claims (8)

[Claims] 1. A laminated dielectric filter comprising: a laminated body in which a dielectric and a conductor are laminated; and an input / output terminal and a ground terminal formed on an outer surface of the laminated body. The laminate includes a main portion formed on one outer surface parallel to the laminating direction of the laminate and a wraparound portion adjacent to the outer surface and wrapping around to another outer surface orthogonal to the laminating direction. The ground electrode formed so as not to overlap with the wraparound portion of the input / output terminal via the dielectric layer and connected to the ground terminal, and the capacitance generated between the ground electrode connected to the input / output terminal and the ground electrode are A laminated dielectric filter comprising: a capacitance forming electrode which is sufficiently larger than a capacitance generated between a wraparound portion of a writing output terminal and a ground electrode. 2. A capacitance generated between the capacitance forming electrode and a ground electrode is at least twice as large as a capacitance generated between a wraparound portion of the input / output terminal and a ground electrode. The laminated dielectric filter as described in the above. 3. The multilayer dielectric filter according to claim 1, wherein the capacitance forming electrode is formed in the same layer as a ground electrode. 4. The multilayer dielectric filter according to claim 1, wherein the wraparound portion of the input / output terminal overlaps a part of the capacitance forming electrode via a dielectric layer. 5. A laminated dielectric filter comprising: a laminated body in which a dielectric and a conductor are laminated; and an input / output terminal and a ground terminal formed on an outer surface of the laminated body. The laminate includes a main portion formed on one outer surface parallel to the laminating direction of the laminate and a wraparound portion adjacent to the outer surface and wrapping around to another outer surface orthogonal to the laminating direction. And a ground electrode formed so as not to overlap with the wraparound portion of the input / output terminal via a dielectric layer and connected to the ground terminal. The length of the wraparound portion is different from that of the main portion of the input / output terminal. The laminated dielectric filter is 50% or less of the distance from the side of the ground electrode facing the main part. 6. The laminated dielectric filter according to claim 5, further comprising a characteristic measuring terminal formed integrally with the wraparound portion on an outer surface facing the mounting destination during mounting. 7. The multilayer dielectric filter according to claim 6, wherein the width of the characteristic measuring terminal is smaller than the width of the input / output terminal. 8. The laminated dielectric filter according to claim 6, wherein the characteristic measuring terminal is formed so as not to overlap with the ground electrode via a dielectric layer. .