JPH09312505A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the Q0 (sharpness Q at no load) from being deteriorated and to obtain a desired external coupling without changing a forming position of an input/output electrode by tilting a center axis of a throughhole with respect to an outer face of a dielectric block. SOLUTION: An opening of each throughhole 6 having an inner conductor 3 on its inner peripheral face, having a connection conductor 7 used to connect to an input output electrode 5 and leading toward the input output electrode 5 is formed tilted to a side face of a dielectric block 1 to get near the bottom side of the block 1. And then the area of the side face of the input output electrode 5 is made smaller than that of a conventional filter. That is, in this dielectric filter, the center axis of each throughhole 6 is formed tilted toward the bottom face and the side face to make the area of the side face of the input output electrode 5 small. Through the constitution above, since the area of the side face of the input output electrode 5 is made smaller than that of a conventional filter, the deterioration in the Q0 is prevented and characteristics such as an insertion loss are improved. Furthermore, the standardization of the input output electrode is made possible and the mounting cost is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of resonator holes formed in a dielectric block, an inner conductor formed on the inner peripheral surface of the resonator hole and an input / output formed on the outer surface of the dielectric block. The present invention relates to a dielectric filter in which electrodes are directly connected to obtain external coupling.

[0002]

2. Description of the Related Art FIG. 3 shows the structure of a conventional dielectric filter in which a dielectric block is used to directly connect an inner conductor and an input / output electrode to obtain external coupling. 3A is a perspective view, and FIG. 3B is a cross-sectional view taken along line XX of FIG.
In addition, in the following figures, the dot-painted portion indicates a portion (conductor non-forming portion) where the base material of the dielectric block is exposed.

In this dielectric filter, as shown in FIG. 3 (a), an inner conductor 3 which functions as a resonance conductor is formed on the inner peripheral surface of the rectangular parallelepiped dielectric block 1 by penetrating between a pair of opposing end faces. The formed resonator holes 2, 2 and 2 are formed, the outer conductor 4 that functions as a ground conductor is formed on substantially the entire outer surface of the dielectric block 1, and the input / output electrodes 5 are provided at predetermined positions on the outer conductor 4. 5 is formed. Then, through holes 6, 6 are provided between each input / output electrode 5 and the corresponding inner conductor 3, and each input / output electrode 5 is connected by the connecting conductor 7 formed on the inner surface of each through hole 6. It is directly connected to the corresponding inner conductor 3.

Each inner conductor 3 is electrically connected to the outer conductor 4 at one opening surface of each resonator hole 2 (a front surface in FIG. 3A, hereinafter referred to as an end surface on the short-circuit side) and the other opening surface ( Figure 3
On the back surface in (a), hereinafter referred to as the open side end surface) side, the inner conductor non-forming portion 3a is provided in the vicinity thereof and the outer conductor 4 is formed.
And are separated.

The input / output electrodes 5 and 5 are formed near the end face on the short-circuit side, and are formed across the bottom face (the upper face in FIGS. 3A and 3B) and the side face which are the mounting faces, and are surrounded by the outside. A conductor non-formation portion 5a is provided and separated from the outer conductor 4. The reason why the input / output electrode 5 is formed across the side surface is to increase the soldering strength.

Each through hole 6 is formed perpendicularly to the side surface on which the central axis corresponds to the input / output electrode 5.

This dielectric filter is constructed so as to obtain external coupling by directly connecting the input / output electrodes 5 and the inner conductors 3 corresponding thereto, and the through holes 6 in the axial direction of the resonator hole are formed. The degree (strength) of external coupling changes depending on the formation position, that is, the connection position of the connection conductor 7 with the inner conductor 3.

[0008]

However, in the above-mentioned conventional dielectric filter, since the central axis of each through hole is formed perpendicularly (90 °) to the side surface on which the input / output electrode is formed, The area of the output electrode increases,
There is a problem that Qo (no load Q) of the dielectric filter is lowered. In other words, since the opening of the through hole is substantially the center of the side surface and the input / output electrode formed on the side surface needs to be formed up to the position including the opening of the through hole, the area of the input / output electrode is inevitably large. Had to do.

Further, when the formation position of the through hole 6 is changed to change the degree of external coupling, that is, in order to obtain a desired external coupling, the formation position of the input / output electrode 5 must be changed each time. There was a problem that it was difficult to standardize the input / output electrodes.

Therefore, it is an object of the present invention to reduce the area of the input / output electrodes and thus prevent the Qo from decreasing, and also to achieve a desired external coupling without changing the formation position of the input / output electrodes. It is to provide a dielectric filter that can be obtained.

[0011]

In order to achieve the above-mentioned object, the present invention is formed between a rectangular parallelepiped-shaped dielectric block and a pair of end faces of the dielectric block, and an inner conductor is formed on the inner peripheral surface. A plurality of resonator holes, an outer conductor formed on the outer surface of the dielectric block, and an insertion hole formed at a predetermined location of the outer conductor across the bottom surface and the side surface of the dielectric block. A through hole formed between an output electrode and the input / output electrode and the inner conductor corresponding to the input / output electrode, and having a connection conductor formed on the inner peripheral surface for connecting the input / output electrode and the inner conductor. In the dielectric filter consisting of, the central axis of the through hole is inclined with respect to the outer surface of the dielectric block.

According to the above construction, the through hole in which the connection conductor for connecting the inner conductor and the input / output electrode is formed is formed to be inclined, so that the opening of the through hole is formed on the bottom surface or the bottom surface of the dielectric block. It can be formed on the side surface closer to the (mounting surface) side. Therefore, the area of the input / output electrode formed on the side surface of the dielectric block can be reduced, and the reduction of Qo can be prevented. That is, it is possible to set the minimum area in consideration of the soldering strength that allows the input / output electrodes.

Further, without changing the formation position of the input / output electrode, the through hole formation position on the resonator hole side, that is, the connection position of the connection conductor with the inner conductor can be set to an arbitrary position, and the desired external coupling can be achieved. Can be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof. In the following drawings, the same reference numerals are given to those having the same or the same functions as the conventional example.

The structure of the dielectric filter according to the first embodiment of the present invention is shown in FIG. FIG. 1A is a perspective view and FIG.
FIG. 3 is a sectional view taken along line XX of FIG.

In the dielectric filter of the present embodiment, the connection conductor 7 for connecting the inner conductor 3 and the input / output electrode 5 to the inner peripheral surface thereof.
Each of the through holes 6 formed with is formed so as to be inclined so that the opening on the input / output electrode 5 side is the side surface of the dielectric block 1 and is closer to the bottom surface (mounting surface) side. The side surface area is formed smaller than the conventional one.

That is, in the dielectric filter of this embodiment, in order to reduce the area of the side surface portion of the input / output electrode 5,
The central axis of each through hole 6 is formed to be inclined with respect to the bottom surface and the side surface. The configuration other than the above is the same as the configuration described in FIG. 3 of the conventional example, and the description thereof will be omitted.

In the configuration of this embodiment, the input / output electrode 5
Is formed smaller than that of the conventional one, so that the reduction of Qo is suppressed and the characteristics such as insertion loss are improved.

FIG. 2 is a perspective view of a dielectric filter according to the second embodiment of the present invention. In the dielectric filter of the present embodiment, each through hole 6 in which the connecting conductor 7 is formed has an opening on the input / output electrode 5 side that is a side surface of the dielectric block 1 and is closer to the bottom surface (mounting surface) side. As described above, the opening on the side of the resonator hole 2 is formed so as to be inclined so as to be closer to the end surface on the short-circuit side, and the area of the side surface of the input / output electrode 5 is smaller than that of the conventional one.

That is, in the dielectric filter of this embodiment, in order to reduce the area of the side surface portion of the input / output electrode 5,
In addition, in order to obtain a larger external coupling, the central axis of the through hole 6 is formed to be inclined with respect to the end face on the short-circuit side, the bottom face and the side face. For configurations other than the above, FIG.
Since the configuration is the same as that described in 1 above, the description thereof is omitted.

In the structure of this embodiment, the input / output electrode 5
Area is smaller than that of the conventional one, and the connection position of the connection electrode 7 with the inner conductor 3 is formed closer to the end surface on the short-circuit side, so that a decrease in Qo is suppressed and a larger external coupling is obtained. Has been. On the contrary to the present embodiment, the external coupling can be reduced by inclining the through hole 6 so that the connecting position of the connecting conductor 7 and the inner conductor 3 is separated from the end face on the short-circuit side.

By forming the through holes in a slanted manner as described above, the degree of external coupling can be easily set without changing the formation position of the input / output electrodes, and various dielectric blocks having the same shape can be used. It is possible to obtain various filter characteristics. That is, since the input / output electrodes can be standardized, it is possible to standardize the mounting substrate such as standardizing the pattern of the mounting substrate and reduce the mounting cost.

In each of the above-described embodiments, the through hole 6 has a circular cross section and its central axis is a straight line, but the through hole 6 may have any shape, for example, an ellipse, The cross-sectional shape may be a quadrangle or the like, and the central axis thereof may be a meandering curve. Further, an opening of the through hole on the input / output electrode side may be formed on the bottom surface of the input / output electrode.

Further, the shape of the resonator hole 2 is not limited to the circular cross section but may be another shape such as an elliptical shape, and the inner diameters of the open side end surface side and the short side end surface side are different. Different resonator holes may be so-called step holes.

Further, the number of stages of the dielectric filter, that is, the number of resonator holes is not limited to that in the above-mentioned embodiment, but it is applicable to a dielectric filter in which two or more resonator holes are formed in one dielectric block. The invention can be applied.

[0026]

As described above, according to the dielectric filter of the present invention, since the through hole in which the connection conductor for connecting the inner conductor and the input / output electrode is formed is inclined, Since the opening of the hole is formed on the bottom surface of the dielectric block or on the side surface near the bottom surface (mounting surface) side, the area of the input / output electrodes formed on the side surface of the dielectric block can be reduced, resulting in a decrease in Qo. And the characteristics such as insertion loss can be significantly improved.

Further, without changing the formation position of the input / output electrodes, the through hole formation position on the resonator hole side, that is, the connection position of the connection conductor with the inner conductor is set to an arbitrary position to obtain a desired external coupling. Therefore, the input / output electrodes can be standardized, and the mounting cost can be reduced by standardizing the mounting board.

[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 taken along line XX of FIG.

FIG. 2 is a perspective view of a dielectric filter according to a second embodiment of the present invention.

FIG. 3A is a perspective view of a conventional dielectric filter, and FIG. 3B is a sectional view taken along line XX of FIG.

[Explanation of symbols]

 1 Dielectric Block 2 Resonator Hole 3 Inner Conductor 4 Outer Conductor 5 Input / Output Electrode 6 Through Hole 7 Connection Conductor

Claims (1)

[Claims] 1. A rectangular parallelepiped dielectric block, a plurality of resonator holes formed between a pair of end faces of the dielectric block and having inner conductors formed on an inner peripheral surface, and an outer surface of the dielectric block. The formed outer conductor, the input / output electrode formed at a predetermined location of the outer conductor across the bottom surface and the side surface of the dielectric block, and corresponding to the input / output electrode and the input / output electrode. A dielectric filter comprising a through hole formed between the inner conductor and a connection conductor for connecting the input / output electrode and the inner conductor on an inner peripheral surface thereof, wherein a central axis of the through hole is A dielectric filter characterized by being inclined with respect to an outer surface of a dielectric block.