JP2002084103A - Dielectric filter and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact dielectric filter, having improved characteristics by adopting filter structure for miniaturization without changing the volume of a dielectric, especially for reducing the occupancy area of a substrate, even though it has not been sufficient to cope with the needs for miniaturizing a radio equipment terminal, since wavelength in a waveguide becomes smaller, in proportion to the square of the dielectric constant of the dielectric in the waveguide filter. SOLUTION: This dielectric filter 1 has a dielectric substrate 4, where at least two dielectric plates 2 and 3, are laminated for integration. Island-like I/O electrodes 7 and 8 are formed in contact with the side of a pair of main surfaces of the dielectric substrate 4, and an internal ground electrode 5 having an opening 6 for coupling is provided on the lamination interface of the dielectric plate 4. Additionally, ground conductors 9, 10, and 13 are formed on a pair of main and side surfaces of the dielectric substrate 4, so that the earth conductors are separated and insulated form the I/O electrodes 7 and 8, and at the same time, are equipped with conductor exposure sections 11 and 12 in a specific shape that include the I/O electrodes 7 and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type dielectric filter used for radio equipment, and more particularly to a structure of a small dielectric filter and a method of manufacturing the same.

[0002]

2. Description of the Related Art Waveguide filters are frequently used in the high frequency range because they use air as a dielectric and have a high Q value even at high frequencies. However, in a waveguide filter, the wavelength in the waveguide decreases in proportion to the power of the dielectric constant of the dielectric, so that the size of the waveguide filter that forms a resonator using air having a dielectric constant of 1 is small. There is a drawback that it cannot be used for a wireless device terminal having a low frequency of about 5 GHz, inevitably becoming large.

[0003] Therefore, a compact dielectric filter has been developed by packing a dielectric having a high dielectric constant inside a waveguide. For example, JP-A-11-274815 discloses a filter using two λ / 4 resonators as the smallest dielectric filter. FIG. 9 schematically shows the configuration of this filter, which has a structure in which two λ / 4 resonators are formed in a rectangular parallelepiped dielectric 100. In the center of the dielectric 100, a through hole 101 in which a ground conductor is formed is formed.
The coupling between the resonators is adjusted. Input / output electrodes 102 and 103 are formed on two opposing sides of the dielectric 100 so as to be separated and insulated from the ground electrode 104. Dielectric side surfaces 105, 10 and 10 where these input / output electrodes 102, 103 are in contact
Reference numeral 6 denotes an open surface of the λ / 4 resonator, in which no ground conductor is formed. The length L of the dielectric side surfaces 105 and 106 is about λ
/ 2, and a ground conductor is formed on the two side surfaces 107 and 108 that are in contact with the dielectric side surfaces 105 and 106, thereby forming a λ / 2 resonator and enhancing the resonance phenomenon.

FIG. 10 shows the filter characteristics when the dielectric filter shown in FIG. 9 is manufactured with a dielectric material having a dielectric constant of 37 and a size of 6 × 6 mm. It can be seen from the graph of FIG. 10 that this dielectric filter exhibits the characteristics of a band-pass filter having a center frequency of 6.8 GHz. Not enough to meet the needs.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed to solve such a conventional problem, and has as its object to provide a small-sized dielectric filter having good characteristics.

[0006]

It is known that the Q value of a dielectric resonator used in a dielectric filter increases as the volume of the dielectric material increases for the same dielectric material. . The higher the Q value, the better the filter characteristics including the passband insertion loss and the filter steepness. Therefore, the larger the filter is, the better the performance is, and there is a risk that the simple miniaturization is accompanied by the performance degradation. Then, the inventor studied a filter structure that can be reduced in size without changing the volume of the dielectric, and in particular, can reduce the occupied area of the substrate. As a result, instead of coupling two resonators each composed of a rectangular parallelepiped dielectric substrate on the side surface, the principal surfaces having the largest area are coupled, and furthermore, by devising the mounting direction and electrode formation, The present inventors have found that the occupied area of the substrate can be reduced to の or less of the conventional one, and arrived at the present invention.

Specifically, a pair of main surfaces of a dielectric substrate
An input / output electrode extending up to the edge and an earth conductor separated and insulated from the input / output electrode are formed, and λ /
The ground conductor is formed except for the side surface constituting the open surface of the four resonator. By coupling two λ / 4 resonators having such a structure,
A part of the internal ground electrode formed at the interface to be joined is removed to form a dielectric exposed portion, ie, an opening.
Are coupled. With such a structure, the area occupied by the substrate (projected area) can be reduced without reducing the volume of the dielectric, and since the input / output electrodes reach the same side surface, they must be surface-mounted. Becomes possible.

When the dielectric filter described in Japanese Patent Application Laid-Open No. H11-274815 is modified so as to satisfy the above requirements, a device having the structure shown in FIG. 11 can be obtained. In this filter, input / output electrodes 202 and 203 are formed on two dielectric substrates 200 and 201 having a size of (λ / 4) × (λ / 2) along a side having a length of λ / 2. Then, a ground electrode is formed separately and insulated from these input / output electrodes. These dielectric substrates 200 and 201 are stacked such that the input / output electrodes 202 and 203 are on the same side, and the side surface (the shaded surface) where the input / output electrodes 202 and 203 are in contact is an open surface. Ground conductor 2 on the other remaining surface
04 is formed.

The device shown in FIG. 11 did not exhibit filter characteristics. This is because the open surfaces of the two λ / 4 resonators are formed on the same surface and are adjacent to each other with the ground conductor formed at the interface between the two λ / 4 resonators therebetween. It has been found that the cause is that the λ / 4 resonators are strongly coupled via the surface, and the filter waveform disappears due to the strong coupling.

Therefore, in the present invention, a ground conductor is formed along at least one or more sides between the ground conductor formed on the front and back main surfaces and the ground conductor formed on the four side surfaces. An unexposed strip-shaped dielectric exposed portion is provided. This dielectric exposed portion becomes an open surface of each resonator, and is separated by a ground conductor formed on the side surface.
That is, according to the present invention, a filter is formed in which two λ / 4 resonators each having the strip-shaped exposed dielectric portion as an open surface are coupled via an opening formed in the internal ground electrode. As a result, the coupling between the two λ / 4 resonators is weakened, filter characteristics can be exhibited, and the area occupied by the dielectric substrate can be reduced without changing the volume of the substrate. Therefore, in the present invention, it is necessary that ground electrodes are formed on all four side surfaces.

Although the input / output electrodes do not necessarily need to extend to the edge, it is desirable that the two input / output electrodes are formed so as to be in contact with the same side surface for surface mounting. Further, the input / output electrodes may be further extended to a part of the side surface. By setting the side surface in contact with the input / output electrode as the mounting lower surface, surface mounting becomes possible, and the area occupied by the dielectric substrate can be further reduced.

The dielectric filter according to the present invention has a short circuit at both ends λ /
In order to function as a two-resonator, its longitudinal dimension is λ / 2
However, it is also possible to replace the both-end short-circuited λ / 2 resonator with a one-side open λ / 4 resonator by using the above method. A filter in which a strip having no ground conductor is formed over two adjacent sides can be formed, and further downsizing can be realized.

The dielectric filter according to the present invention is classified into two types, one having a large volume and one having a small volume. Therefore, it is desirable to use these two types properly according to the required filter characteristics and dimensions. In fact, when the volume of the filter is reduced, the Q of the resonator is reduced accordingly, and the filter characteristics are slightly deteriorated. Therefore, as a result of studying a structure capable of improving the filter performance despite the miniaturization, it was found that the ground conductor and the input / output electrodes formed parallel to the main surface were multilayered with a thin dielectric therebetween. As a result, it has been found that by dispersing a current to each conductor layer, electric resistance can be reduced, conductor loss can be reduced, and filter performance can be improved. However, it is, of course, necessary to optimize the design for the multilayer structure.

Therefore, the dielectric filter according to the present invention is manufactured integrally by laminating and sintering a ceramic green sheet on which a conductor pattern is formed by a metal paste, that is, a multilayer ceramic structure process that facilitates multilayering. It is desirable to manufacture using the method which does.
By using this method, it is possible to realize, at low cost, a configuration in which the ground conductor formed on the joint surface between the two resonators has a multilayer structure such as a double or triple structure with a thin dielectric layer interposed therebetween.
The multilayered ground conductor can prevent deterioration of filter performance due to conductor loss. Also, multilayered ground conductors and input / output electrodes formed on the front and back main surfaces,
This is effective because the same purpose can be achieved. It is desirable that these multilayered conductors are connected by a plurality of via holes so that the same potential can be maintained.

In view of the above description, the invention of claim 1 is directed to a pair of opposing main surfaces formed by laminating and integrating at least two dielectric plates and a side surface in contact with the main surfaces. A dielectric filter comprising a dielectric substrate having: an island-shaped input / output electrode formed respectively in contact with sides of the pair of main surfaces; and a coupling opening at a lamination interface of the dielectric plate. An internal ground electrode formed so as to have a dielectric exposed portion of a predetermined shape including the input / output electrode on the pair of main surfaces and side surfaces so as to be insulated and separated from the input / output electrode. And a ground conductor formed on the dielectric filter.

According to a second aspect of the present invention, the dielectric substrate has a rectangular parallelepiped shape, and the pair of input / output electrodes is formed so as to be in contact with one side surface of the dielectric substrate. It is characterized by being formed in a belt shape along the one side surface.

According to a third aspect of the present invention, the dielectric substrate has a rectangular parallelepiped shape, a first side surface, a second side surface in contact with one end of the first side surface, and the other end of the first side surface. The third in contact with
And a pair of the input / output electrodes is formed so as to be in contact with a first side surface of the dielectric substrate, and the dielectric exposed portion is formed between the first side surface and the second side surface. It is characterized by being formed in an L-shape along.

According to a fourth aspect of the present invention, the pair of input / output electrodes is formed at a corner where the first side surface and the second side surface intersect. The invention of claim 5 is
One of the input / output electrodes is formed at a corner where the first side surface and the second side surface intersect, and the other of the input / output electrode intersects the first side surface and the third side surface. It is characterized in that it is formed at the corner where it is formed.

The invention according to claim 6 is characterized in that at least one of the input / output electrode, the ground conductor, and the internal ground electrode is a multilayer conductor layer. The invention according to claim 7 is a step of forming a laminate in which a predetermined conductor pattern is formed by a material that becomes a conductor by firing, on a green sheet that becomes a dielectric ceramic by firing, and simultaneously firing the laminate. And a method for manufacturing the dielectric filter according to any one of claims 1 to 6.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of a dielectric filter according to the present invention will be described below in detail with reference to FIGS. In these figures, the same reference numerals indicate the same or similar components.

FIGS. 1A, 1B and 1C schematically show one embodiment of the dielectric filter according to the present invention, wherein the dielectric filter 1 comprises two sheets. It has a dielectric substrate 4 in which dielectric plates 2 and 3 are laminated and integrated. The dielectric substrate 4 is, for example, rectangular, and the length of the long side is about λ /
2. The length of the short side is about λ / 4. A pair of wide surfaces facing each other of the dielectric substrate 4 is referred to as a main surface, and two sets of surfaces in contact with the main surface are referred to as side surfaces. An internal earth electrode 5 having a shape shown in FIG. 1A is sandwiched between the dielectric plate 2 and the dielectric plate 3. An opening 6 having a predetermined size is formed at an appropriate position on one of the long sides.

As shown in FIG. 1B, the dielectric substrate 4
On one main surface having an area of (λ / 2) × (λ / 4), an input / output electrode 7 having a predetermined shape such as a rectangle is formed at an appropriate position along one long side. On the other main surface, an input / output electrode 8 having a predetermined shape is formed as shown in FIG. As shown in (b), these input / output electrodes 7 and 8 are formed so as to be in contact with the same side surface of the dielectric substrate 4.

Further, a ground conductor 9 is formed so as to cover the entire surface of one main surface and so as to be separated and insulated from the input / output electrode 7, and similarly, a ground conductor 10 covers the entire surface of the other main surface. And insulated and isolated from the input / output electrode 8. Thus, a strip-shaped open surface or a dielectric exposed portion 11 is provided between the input / output electrode 7 and the ground conductor 9, and a strip-shaped open surface or the dielectric exposed portion 11 is also provided between the input / output electrode 8 and the ground conductor 10. A part 12 is provided. Ground conductors 9 and 10 are input / output electrodes 7 and 8 on each main surface and open surfaces 11 and
The reason why it is formed on the entire surface except for the surface 12 is to enable surface mounting.

Ground conductors 13 are also formed on the four side surfaces of the dielectric substrate 4. However, gaps 14 and 15 having a required width are formed to separate and insulate the input / output electrodes 7 and 8 from the ground conductor 13 on the side surface. The ground conductor 13 is formed so as to be electrically connected to the internal ground electrode 5 sandwiched between the dielectric plates 2 and 3 and the ground conductors 9 and 10 formed on both main surfaces.

In FIG. 1, the input / output electrodes 7, 8
Is formed at the center of one long side, but the point is that the input / output electrodes 7 and 8 only need to be formed in the open surfaces 11 and 12, and the position is not only at the center of the long side. Can be formed at any position. Further, the two input / output electrodes 7 and 8 may be formed at different positions along one long side. Furthermore, the open surfaces 11 and 12 do not have to be formed on the main surface, and may be provided on the side surfaces.
You may make it straddle a main surface and a side surface.

A dielectric filter 1 having the structure shown in FIG. 1 was constructed by using two dielectric plates 2 and 3 having a dielectric constant of 70 and a size of 5.0 × 2.7 mm. The size of the opening 6 of the internal earth electrode 5 is 0.4 × 0.4 mm, the size of the input / output electrodes 7 and 8 is 1.0 × 0.6 mm, and the thickness between the input / output electrodes is 2.5 mm. And the width of the open surfaces 11 and 12 is 0.5 mm
Met. When the frequency characteristics of the dielectric filter were measured, a graph shown in FIG. 2 was obtained. The solid line in FIG. 2 indicates the pass characteristic of the filter, and the dotted line indicates the reflection characteristic. From these graphs, it can be seen that the dielectric filter has a center frequency of 5.8.
It can be seen that the filter has the characteristics of a GHz band-pass filter.

FIGS. 3A, 3B and 3C schematically show a dielectric filter according to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment shown in FIG. 1 is that, as clearly shown in the figure, the open surfaces 11 and 12 extend from one long side where the input / output electrodes 7 and 8 come into contact. This is a point formed in an L shape along one short side adjacent to the long side.

Using two dielectric plates 2 and 3 having a dielectric constant of 70 and a size of 3.2 × 2.2 mm, input / output electrodes 7 and 8 are formed at the center of the long side in FIG. The dielectric filter 1 was configured. The size of the opening 6 of the internal earth electrode 5 is 0.3
× 0.3 mm, and the dimensions of the input / output electrodes 7 and 8 are 1 ×
The thickness between the input and output electrodes was 2.5 mm, and the width of the L-shaped open surfaces 11 and 12 was 0.5 mm. When the frequency characteristics of the dielectric filter were measured, a graph shown in FIG. 4 was obtained. The solid line in FIG. 4 indicates the pass characteristic of the filter, and the dotted line indicates the reflection characteristic. From these graphs, it can be seen that this dielectric filter has the characteristics of a bandpass filter having a center frequency of 5.8 GHz.

In the second embodiment shown in FIG.
The input / output electrodes 7 and 8 need only be provided in the open surfaces of the filter, that is, in the L-shaped open surfaces 11 and 12, and the position does not need to be at the center of the long side. FIG. 5 shows the input / output electrodes 7 and 8 at the corners where the long sides and the short sides intersect in the second embodiment shown in FIG. 3 along these sides and at the same position as viewed from the main surface. The example shown in FIG. Since the open surfaces 11 and 12 are L-shaped, the input / output electrodes 7 and 8 formed at the corners are also preferably L-shaped.

A dielectric filter 1 having the structure shown in FIG. 5 was constructed by using two dielectric plates 2 and 3 having a dielectric constant of 70 and a size of 2.7 × 2.7 mm. The size of the opening 6 of the internal earth electrode 5 is 0.2 × 0.2 mm, the size of the input / output electrodes 7 and 8 is 1.0 × 0.6 mm, and the thickness between the input / output electrodes is 2.5 mm. And the width of the open surfaces 11 and 12 is 0.8 mm
Met. When the frequency characteristics of the dielectric filter were measured, a graph shown in FIG. 6 was obtained. The solid line in FIG. 6 indicates the pass characteristic of the filter, and the dotted line indicates the reflection characteristic. From these graphs, it can be seen that the dielectric filter has a center frequency of 5.8.
It can be seen that the filter has the characteristics of a GHz band-pass filter.

In the second embodiment shown in FIG. 3, the input / output electrodes 7, 8 do not need to be formed at the same position when viewed from the main surface. FIG. 7 shows that in the second embodiment shown in FIG. 3, an input / output electrode 7 is formed at a corner where one long side and one short side adjacent to the long side intersect. Is formed at a corner where the long side intersects with the other short side adjacent to the long side. Therefore, in this example, the input / output electrodes 7 and 8 are located at both ends of one long side.

Here, (a), (b) and (c) of FIG.
The third embodiment of the dielectric filter according to the present invention will be described with reference to FIG. This embodiment differs from the first and second embodiments described so far in that the number of dielectric plates constituting the dielectric substrate 4 is three instead of two.
And correspondingly, the internal ground electrode is not one but two.
This is a point that a plurality of sheets are provided and a multilayer structure is provided.

That is, the dielectric substrate 4 comprises the first dielectric plate 2,
The second dielectric plate 3 and the thin third dielectric plate 16 sandwiched between them are laminated and integrated in this order,
A first internal ground electrode 5a having a coupling opening 6a formed between the first dielectric plate 2 and the third dielectric plate 16
Is formed, and a second internal ground electrode 5b having an opening 6b for coupling is also formed between the third dielectric plate 16 and the second dielectric plate 3. The third dielectric plate 16 has a thickness of, for example, 60 μm, and as shown in FIG.
First internal ground electrode 5a and second internal ground electrode 5b
Are electrically connected to each other through a via hole having a diameter of, for example, 0.6 mm formed at an interval of, for example, 1.0 mm.
Are maintained at the same potential.

As described above, by forming the internal ground electrode in a multilayer structure, the conductor loss of the filter can be reduced.
Filter performance can be improved. Such a reduction in conductor loss can be realized not only by increasing the number of layers of the internal ground electrode, but also by increasing the number of layers of one or both of the ground conductors 9 and 10 formed on the main surface.

As a method for manufacturing the dielectric filters shown in FIGS. 1, 3, 5, 7, and 8 described above, a multilayer ceramic manufacturing process is suitable. Applying this multilayer ceramic manufacturing process, the dielectric filter of the present invention is manufactured by the following steps. (1) a ceramic mainly composed of _{BaO-Nd203-TiO 2 B 2} O 3, were added aid GeO ₂ or the like, the dielectric ceramics of the silver paste fired simultaneously possible dielectric constant 70 in a sheet form Form green sheets. (2) I / O electrodes and ground conductors are screen-printed on one surface of the formed green sheet using a silver paste in a predetermined pattern. An internal ground electrode is screen-printed on one surface of another green sheet in a predetermined pattern. (3) Green sheet with input / output electrodes and ground conductor printed on the bottom, green sheet with internal ground electrode printed, green sheet with input / output electrodes and ground conductor printed on green sheet Are laminated in this order with a predetermined number of unprinted green sheets sandwiched between the green sheets, and laminated by pressing to integrate them. (4) The integrated green sheet is cut into a predetermined size to form a laminate. (5) On the side surface of the laminate, a predetermined pattern of the ground conductor is screen-printed using a silver paste so as to be electrically connected to the ground conductor and the internal ground electrode. (6) 900 ° C laminated body with ground conductor printed on the side
Baking.

In the above step, when the earth conductor or the internal earth electrode is multi-layered and connected to each other by a via hole, the above step (2)
In this method, after a via hole is previously formed in a green sheet using a punch or the like, a silver paste may be filled in the via hole by screen-printing a ground conductor or an internal ground electrode using a silver paste.

In the case of multi-layering by laminating individual dielectrics, as the number of layers increases, the assembling process becomes more complicated and the manufacturing cost increases. However, when the multilayer ceramic manufacturing process is applied as described above,
Since the dielectric substrate can be manufactured integrally, the earth conductor or the internal earth electrode can be easily multilayered.

[0038]

As can be understood from the above description of the embodiments and the modifications of the dielectric filter according to the present invention, the present invention provides a dielectric filter which is extremely miniaturized as compared with the prior art. The use of the multilayer ceramic manufacturing process provides a special effect that a multilayer structure for reducing the conductor loss of the filter can be easily and inexpensively realized.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams schematically showing a first embodiment of a dielectric filter according to the present invention, wherein FIG. 1A is a perspective view of an internal ground electrode, and FIG. (C) is a perspective view of the other main surface.

FIG. 2 is a diagram showing a result of measuring frequency characteristics of a specific example of the dielectric filter shown in FIG.

3A and 3B are diagrams schematically illustrating a second embodiment of the dielectric filter according to the present invention, wherein FIG. 3A is a perspective view of an internal ground electrode, and FIG. (C) is a perspective view of the other main surface.

4 is a diagram showing a result of measuring frequency characteristics of a specific example of the dielectric filter shown in FIG.

5A and 5B are diagrams schematically showing a modification of the dielectric filter shown in FIG. 3, wherein FIG. 5A is a perspective view of an internal ground electrode, and FIG. (C) is a perspective view of the other main surface.

6 is a diagram showing a result of measuring frequency characteristics of a specific example of the dielectric filter shown in FIG.

FIG. 7 is a view schematically showing another modified example of the dielectric filter shown in FIG. 3, (a) is a perspective view of an internal ground electrode,
(B) is a perspective view of the dielectric filter as viewed from one main surface, and (c) is a perspective view of the other main surface.

8A and 8B are diagrams schematically showing a third embodiment of the dielectric filter according to the present invention, wherein FIG. 8A is a perspective view of an internal ground electrode, and FIG. (C) is a perspective view of the other main surface.

FIG. 9 is a diagram schematically showing an example of a conventional dielectric filter.

FIG. 10 is a diagram illustrating a frequency characteristic of the dielectric filter illustrated in FIG. 9;

FIG. 11 is a diagram for explaining a process leading to the idea of the present invention.

[Explanation of symbols]

 1: dielectric filter, 2, 3, 16: dielectric plate, 4: dielectric substrate, 5, 5a, 5b: internal ground electrode, 6, 6a, 6b: opening, 7, 8: input / output electrode, 9, 10, 13: ground conductor, 11, 12: open surface, 14, 15: gap

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuya Kurihara 1-8 Fuso-cho, Amagasaki-shi, Hyogo Sumitomo Metal Industries, Ltd. Electronics Technology Research Laboratory F-term (reference) 5J006 HC01 JA01 LA23 NA00 NA06 NA06 ND05

Claims (7)

[Claims] 1. A dielectric filter comprising a dielectric substrate formed by laminating and integrating at least two dielectric plates and having a pair of opposing main surfaces and a side surface in contact with the main surfaces, Island-shaped input / output electrodes respectively formed in contact with the sides of the pair of main surfaces; and an internal ground electrode formed to have a coupling opening at a lamination interface of the dielectric plates; and A ground conductor formed on the main surface and the side surface so as to be separated and insulated from the input / output electrode and to have a dielectric exposed portion of a predetermined shape including the input / output electrode,
A dielectric filter comprising: 2. The dielectric filter according to claim 1, wherein said dielectric substrate has a rectangular parallelepiped shape, and said pair of input / output electrodes is formed so as to be in contact with one side surface of said dielectric substrate. The dielectric filter, wherein the dielectric exposed portion is formed in a band shape along the one side surface. 3. The dielectric filter according to claim 1, wherein the dielectric substrate has a rectangular parallelepiped shape, a first side surface, a second side surface in contact with one end of the first side surface, A third side surface in contact with the other end of the first side surface, a pair of the input / output electrodes is formed so as to be in contact with the first side surface of the dielectric substrate, and the dielectric exposed portion is the A dielectric filter formed in an L-shape along the first side surface and the second side surface. 4. The dielectric filter according to claim 3, wherein the pair of input / output electrodes is formed at a corner where the first side surface and the second side surface intersect. Dielectric filter. 5. The dielectric filter according to claim 3, wherein one of said input / output electrodes is formed at a corner where said first side surface and said second side surface intersect, and said input / output electrode is Wherein the other is formed at a corner where the first side surface and the third side surface intersect. 6. The dielectric filter according to claim 1, wherein at least one of the input / output electrode, the ground conductor, and the internal ground electrode comprises a multilayer conductor layer. A dielectric filter, characterized in that: 7. The method for producing a dielectric filter according to claim 1, wherein a predetermined conductor is formed on a green sheet that becomes a dielectric ceramic by firing, and a material that becomes a conductor by firing. A manufacturing method, comprising: forming a layered body having a pattern formed thereon; and simultaneously firing the layered body.