JPH08111601A - Dielectric filter - Google Patents

Abstract

PURPOSE: To obtain the dielectric filter with excellent yield in which the effect of contraction of a volume is reduced when a dielectric material is baked by covering an inner face or the inner side face and a bottom face of a non- throughhole formed to a forming body made of a dielectric material with an electrode. CONSTITUTION: An inner side face or the inner side face and a bottom face of a non-throughhole 2 made from an upper face to a lower face of a forming body 1 and of a non-throughhole 3 made from the lower side to the upper side with a dielectric material 9 inbetween are covered by electrodes 5, 6 to form an independent resonator. Then the electrode 5 and an input electrode 7, and the electrode 6 and an output electrode 8 or the electrodes 5, 6 form a coupling capacitor via the dielectric material 9, they act respectively like a λ/4 resonator to form 2-stages of dielectric filters. As a result, since the characteristic of the filters of the 2-stages mainly depends on the distance between the bottom faces of the two non-throughholes 2, 3, the dielectric filter hardly receives the contraction of a volume when the dielectric body is baked and the dielectric filter with excellent yield is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter used for communication equipment and the like.

[0002]

2. Description of the Related Art A conventional dielectric filter will be described below with reference to the drawings. FIG. 6 is a perspective view of a conventional dielectric filter, which is described in JP-A-4-103202.

As shown in FIG. 6, a conventional dielectric filter has a molded body 81 made of a dielectric material and two non-through holes 82 provided from one end surface to the other end surface of the molded body 81.
And a ground electrode 85 formed by coating the outer peripheral surface of the molded body 81 with a conductor. Further, on the side surface of the molded body 81, a part of the ground electrode 85 is removed so that the input / output electrode 83
And a non-through hole 84 for adjusting the band is provided on the other end surface facing the non-through hole 82. further,
Inner peripheral surfaces of the two non-through holes are provided with inner peripheral electrodes 86 formed by coating a conductor, and the non-through holes 84 for band adjustment are provided.
The band adjusting electrode 87 formed by coating a conductor on the inner peripheral surface of the
It is a configuration provided with.

With this configuration, before firing the molded body,
Since the non-through holes 84 for adjusting the band are provided, the coupling degree between the non-through holes 82 can be adjusted by changing the depth of the non-through holes 84 in consideration of the band of the dielectric filter. The band characteristic of the dielectric filter can be obtained.

[0005]

In the above structure, the band of the filter is highly dependent on the distance between the non-through holes 82 and the depth of the non-through holes 84 for adjusting the band. However, since the molded body 81 is usually formed by firing, a volume contraction occurs during firing, and the distance between the non-through holes 82 and the non-through holes 8 are reduced.
4 had a problem that the depth of the filter was changed, the band of the filter adjusted before firing was shifted, and the yield of the dielectric filter was deteriorated.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a dielectric filter having a good yield by reducing the influence of volume contraction during firing of the dielectric.

[0007]

To achieve the above object, in a dielectric filter of the present invention, a molded body made of a dielectric material, a non-through hole provided from the upper surface to the lower surface of the molded body, It comprises a non-through hole provided from the lower surface to the upper surface, an earth electrode formed by covering the outer peripheral surface of the molded body with a conductor, and an input electrode and an output electrode provided by removing a part of the earth electrode. The inner surface and the bottom surface of the non-through hole are covered with a conductor to provide an electrode.

[0008]

With the above structure, in the dielectric filter of the present invention, the characteristics of the filter are mainly determined by the distance between the bottom surfaces of the two non-penetrating holes, so that they are less susceptible to the volume contraction during firing of the dielectric. Therefore, a dielectric filter having a high yield can be obtained.

[0009]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1A is a perspective view of a dielectric filter according to the first embodiment of the present invention, and FIG. 1B is a sectional view of the same.

As shown in FIGS. 1 (a) and 1 (b), the dielectric filter of the present invention has a prismatic or cylindrical molded body 1 made of a dielectric material, and a molded body 1 directed from the upper surface to the lower surface. The non-through hole 2 provided from the bottom surface, the non-through hole 3 provided from the lower surface to the upper surface, the ground electrode 4 formed by coating the outer peripheral surface of the molded body with a conductor, and the ground electrode 4 partially removed. It is composed of the input electrode 7 and the output electrode 8 provided, and the non-through holes 2, 3
The inner side surface and the bottom surface are covered with electrodes 5 and 6, respectively.

The characteristics of the dielectric filter having the above structure will be described below. A non-through hole 2 provided from the upper surface to the lower surface of the molded body 1 and a non-through hole 3 provided from the lower surface to the upper surface are formed with the dielectric 9 sandwiched therebetween. The side surface and the bottom surface are covered with electrodes 5 and 6, respectively, to form independent resonators. At this time, a coupling capacitance is generated between the electrode 5 and the input electrode 7, between the electrode 6 and the output electrode 8, and between the electrodes 5 and 6 via the dielectric 9, and each becomes a λ / 4 type resonator, and a two-stage dielectric is formed. Form a body filter.

As a result, the characteristics of the filter are mainly two non-through holes 2, 3 while forming a two-stage dielectric filter.
Since it is determined by the distance between the bottom surfaces of the dielectrics, the dielectric filter is less affected by the volume contraction during firing of the dielectric, and a dielectric filter having a good yield can be obtained.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2A is a perspective view of a dielectric filter according to the second embodiment of the present invention, and FIG. 2B is a sectional view of the same.

As shown in FIGS. 2A and 2B, the dielectric filter of the present invention has a prismatic or cylindrical molded body 11 made of a dielectric material and an upper surface 21 to a lower surface 20 of the molded body 11. , A non-through hole 12 provided toward the upper surface 21, a non-through hole 13 provided from the lower surface 20 to the upper surface 21, and a ground electrode 14 formed by coating the outer peripheral surface of the molded body 11 excluding the upper surface 21 and the lower surface 20 with a conductor. And an input electrode 17 and an output electrode 18 provided by removing a part of the ground electrode 14,
The inner side surface and the bottom surface of the non-through holes 12 and 13 are covered with electrodes 15 and 16, respectively.

The characteristics of the dielectric filter having the above structure will be described below. The non-through hole 12 provided from the upper surface to the lower surface of the molded body 11 and the non-through hole 13 provided from the lower surface to the upper surface are formed with the dielectric 19 interposed therebetween. The side surface and the bottom surface are covered with electrodes 15 and 16, respectively, to form independent resonators.

At this time, between the electrode 15 and the input electrode 17, between the electrode 16 and the output electrode 18, and between the electrodes 15 and 16 is the dielectric 1.
Coupling capacitance is generated via 9 and each becomes a λ / 2 type resonator to form a two-stage dielectric filter.

As a result, the characteristics of the filter are mainly two non-through holes 12, while forming a two-stage dielectric filter.
Since it is determined by the distance between the bottom surfaces of the dielectrics 13, the dielectric filter is less affected by the volume contraction during firing of the dielectric and a dielectric filter having a good yield can be obtained.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of a dielectric filter according to the third embodiment of the present invention. As shown in FIG. 3, the dielectric filter of the present invention has a prismatic or cylindrical molded body 31 made of a dielectric material, a non-through hole 32 provided from the upper surface to the lower surface of the molded body 31, and a lower surface. A non-through hole 33 provided from above to the upper surface, an earth electrode 34 formed by covering the outer peripheral surface of the molded body 31 with a conductor, an input electrode provided by removing a part of the earth electrode 34, and an output electrode. Consists of
The inner surfaces of the non-through holes 32 and 33 are connected to the electrodes 35 and 36, respectively.
It is a structure covered with. At this time, no conductor is provided on the bottom surfaces 29 and 30 of the non-through holes 32 and 33.

The characteristics of the dielectric filter having the above structure will be described below. A non-through hole 32 provided from the upper surface to the lower surface of the molded body 31 and a non-through hole 33 provided from the lower surface to the upper surface are formed sandwiching the dielectric 39. The sides are electrodes 35,
36, each of which forms an independent resonator. At this time, between the electrode 35 and the input electrode, between the electrode 36 and the output electrode,
Further, the electrodes 35 and 36 generate a coupling capacitance through the dielectric 39 to serve as λ / 4 type resonators, respectively, and form a two-stage dielectric filter.

As a result, while forming a two-stage dielectric filter, the characteristics of the filter are mainly two non-through holes 32,
Since it is determined by the distance between the bottom surfaces of 33, the dielectric filter is less affected by volume contraction during firing of the dielectric, and a dielectric filter having a good yield can be obtained.

(Embodiment 4) A fourth embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a sectional view of a dielectric filter according to the fourth embodiment of the present invention. As shown in FIG. 4, the dielectric filter of the present invention comprises a prismatic or cylindrical molded body 41 made of a dielectric material, a non-through hole 42 provided from the upper surface to the lower surface of the molded body 41, and a lower surface. The non-through hole 43 provided from above to the upper surface and the outer peripheral surface of the molded body 41 to the upper surface 51.
And a ground electrode 44 covered with a conductor except the lower surface 52, an input electrode and an output electrode provided by removing a part of the ground electrode 44, and the non-through holes 42, 43.
The inner side surface of is covered with electrodes 45 and 46, respectively. At this time, no conductor is provided on the bottom surfaces 40 and 50 of the non-through holes 42 and 43.

The characteristics of the dielectric filter having the above structure will be described below. A non-through hole 42 provided from the upper surface to the lower surface of the molded body 41 and a non-through hole 43 provided from the lower surface to the upper surface are formed with the dielectric 49 sandwiched between the non-through holes 42, 43. The sides are electrodes 45,
46, each of which forms an independent resonator. At this time, between the electrode 45 and the input electrode, between the electrode 46 and the output electrode,
In addition, the electrodes 45 and 46 generate a coupling capacitance through the dielectric 49 to become λ / 2 type resonators, respectively, and form a two-stage dielectric filter.

As a result, the characteristics of the filter are mainly two non-through holes 42, while forming a two-stage dielectric filter.
Since it is determined by the distance between the bottom surfaces of 43, the dielectric filter is less affected by the volume contraction during firing of the dielectric, and a dielectric filter having a good yield can be obtained.

(Fifth Embodiment) A fifth embodiment of the present invention will be described below with reference to the drawings.

FIG. 5A is a perspective view of a dielectric filter according to the fifth embodiment of the present invention, and FIG. 5B is a sectional view of the same.

As shown in FIG. 5, the dielectric filter of the present invention has a rectangular or columnar molded body 61 made of a dielectric material, and a recessed portion formed on the outer peripheral surface of the molded body perpendicularly to the non-through holes 62 and 63. 70 is provided, and the non-through hole 62 provided from the upper surface to the lower surface of the molded body 61, the non-through hole 63 provided from the lower surface to the upper surface, and the outer peripheral surface of the molded body 61 is covered with a conductor. The ground electrode 64, the input electrode 67 provided by removing a part of the ground electrode 64, and the output electrode 6
In this configuration, the inner side surface and the bottom surface of the non-through holes 62 and 63 are covered with electrodes 65 and 66, respectively.

The characteristics of the dielectric filter having the above structure will be described below. A non-through hole 62 provided from the upper surface to the lower surface of the molded body 61 and a non-through hole 63 provided from the lower surface to the upper surface are formed with the dielectric 69 sandwiched between the non-through holes 62, 63. The side surface and the bottom surface are covered with electrodes 65 and 66, respectively, to form independent resonators. At this time, between electrode 65 and input electrode 67, electrode 66
Between the output electrode 68 and the output electrode 68, and the electrodes 65 and 66 generate a coupling capacitance through the dielectric 69 to serve as a λ / 4 type resonator, forming a two-stage dielectric filter.

As a result, the characteristics of the filter are mainly two non-through holes 62, while forming a two-stage dielectric filter.
Since it is determined by the distance between the bottom surfaces of 63, the dielectric filter is unlikely to be affected by volume contraction during firing of the dielectric, and a dielectric filter having a good yield can be obtained.

Further, the required filter characteristics can be easily realized by changing the depth and width of the concave portion 70 provided on the outer peripheral surface of the molded body.

[0034]

As described above, the dielectric filter of the present invention is provided with a molded body made of a dielectric material, non-through holes provided from the upper surface to the lower surface of the molded body, and from the lower surface to the upper surface. An inner surface of the non-through hole, which comprises a non-through hole, an earth electrode formed by coating the outer peripheral surface of the molded body with a conductor, and an input electrode and an output electrode provided by removing a part of the earth electrode. Alternatively, since the inner surface and the bottom surface are covered with electrodes, the characteristics of the filter are mainly determined by the distance between the bottom surfaces of the two non-penetrating holes, and are less affected by the volume contraction during firing of the dielectric material. That is, a good dielectric filter can be obtained.

[Brief description of drawings]

FIG. 1A is a perspective view of a dielectric filter according to a first embodiment of the present invention, and FIG. 1B is a sectional view of the dielectric filter.

2A is a perspective view of a dielectric filter according to a second embodiment of the present invention, and FIG. 2B is a sectional view of the dielectric filter.

FIG. 3 is a sectional view of a dielectric filter according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a dielectric filter according to a fourth embodiment of the present invention.

FIG. 5A is a perspective view of a dielectric filter according to a fifth embodiment of the present invention. FIG. 5B is a sectional view of the dielectric filter.

FIG. 6 is a perspective view of a dielectric filter according to a conventional example.

[Explanation of symbols]

 1 molded body 2 non-through hole 3 non-through hole 4 ground electrode 5 electrode 6 electrode 7 input electrode 8 output electrode 9 dielectric

Claims (4)

[Claims] 1. A molded body made of a dielectric material, a non-through hole provided from the upper surface to the lower surface of the molded body, a non-through hole provided from the lower surface to the upper surface, and an outer peripheral surface of the molded body. An earth electrode covered with a conductor, and an input electrode and an output electrode provided by removing a part of the earth electrode,
A dielectric filter in which an electrode is provided by coating a conductor on the inner side surface or the inner side surface and the bottom surface of the non-through hole. 2. The ground electrode provided on the upper and lower surfaces of the ground electrode provided on the outer peripheral surface of the molded body, or a part or all of the ground electrode provided on the upper surface is removed.
The dielectric filter described. 3. The dielectric filter according to claim 1, wherein a part or all of the electrode provided on the bottom surface of the non-through hole of the molded body is removed. 4. The dielectric filter according to claim 1, wherein a recess is provided on the outer peripheral surface of the molded body perpendicularly to the non-through hole.