JPH0794910A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To easily obtain large external coupling capacitance without reducing the Q0 of a resonator by forming two inner conductor forming holes corresponding to two I/O electrodes respectively as a shape with a cross section of an approximate square. CONSTITUTION:In this dielectric resonator, two inner conductor forming holes 2 each of which has a cross section of an approximate square are formed so as to be penetrated between a pair of opposite faces of a dielectric block 1 having an approximately rectangular paralleopiped shape. An inner conductor 3 is formed on the inner peripheral face of each hole 2. A pair of I/O electordes 4 are formed on a part of the outer peripheral face of the block 1 and an outer electrode 5 is formed on the whole surface of the external peripheral face excluding the formation area of the I/O electrodes 4. An inner conducor non-formation part is formed in the vicinity of one aperture face of the hole 2 so as to release (separate) the inner conductor 3 from the external conductor 5 and the conductor 3 is short-circuited from the conductor 5 on the other aperture face. An external conductor non-formation part is formed on the perphery of each electrode 4 so that the electrode 4 is formed over a main face and a side face of the block 1 separated by the conductor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator in which at least one inner conductor forming hole is formed in a dielectric block and an outer conductor is formed on the outer surface of the dielectric block.

[0002]

2. Description of the Related Art The structure of a conventional dielectric resonator using a dielectric block is shown in FIG. FIG. 5A is an external perspective view in which the conductor forming portion is hatched. FIG. 11B is a sectional view taken along line XX of FIG.

In FIG. 1, a dielectric block 1 is formed with, for example, two inner conductor forming holes 2 having a circular cross section so as to penetrate between a pair of opposing surfaces. An inner conductor 3 is formed on the inner peripheral surface of each inner conductor forming hole 2. Further, a pair of input / output electrodes 4 are formed at predetermined locations on the outer peripheral surface of the dielectric block 1, and an outer conductor 5 is formed on the entire outer peripheral surface excluding the region where the input / output electrodes 4 are formed. Inner conductor 3
Is provided with a non-formed portion of the inner conductor 3 in the vicinity of one opening surface of the inner conductor forming hole 2, is released (separated) from the outer conductor 5, and is short-circuited with the outer conductor 5 at the other opening surface.

In such a structure, the input / output electrode 4
As shown in FIG. 5B, a coupling capacitance Ce is generated between the inner conductor 3 and the corresponding inner conductor 3.

[0005]

By the way, as in the above-mentioned conventional example, a dielectric resonator in which an input / output electrode is formed by separating a part of the outer conductor formed on the outer peripheral surface of the dielectric block from the outer conductor. In the above, the area of the input / output electrode and the inner peripheral diameter of the inner conductor forming hole are changed to obtain an appropriate external coupling capacitance. Therefore, when a large external coupling capacitance is required, a method of increasing the area of the input / output electrode or increasing the inner peripheral diameter of the inner conductor forming hole is used. However, when the input / output electrodes are enlarged to increase the external coupling capacitance, there is a problem that Qo is lowered. Furthermore, the closer the input / output electrode is to the short-circuited surface (the surface where the inner conductor and the outer conductor are short-circuited), the smaller the effect of increasing the coupling capacitance due to the increase in the area of the input / output electrode. Therefore, it is not possible to obtain a large external coupling capacitance by only changing the area of the input / output electrodes. Further, when the inner peripheral diameter of the inner conductor forming hole is increased to increase the outer coupling capacity, there is a limit to the increase of the outer coupling capacity due to the reduction of Qo and the mechanical strength of the dielectric block. .

Therefore, when a large external coupling capacitance is required, another component such as an external capacitor may be added in some cases.

Therefore, an object of the present invention is to solve the problems of the conventional dielectric resonator as described above, and to improve the Qo of the resonator.
Another object of the present invention is to provide a dielectric resonator in which a large external coupling capacitance can be easily obtained without reducing the value.

[0008]

In order to achieve the above object, a dielectric resonator according to claim 1 of the present invention is provided with at least one inner conductor forming hole inside a dielectric block.
An input / output in which an inner conductor is formed on the inner peripheral surface of the inner conductor forming hole, an outer conductor is formed so as to cover substantially the entire outer peripheral surface of the dielectric block, and a part of the outer conductor is capacitively coupled with the inner conductor. In the dielectric resonator provided with electrodes, the inner conductor forming holes corresponding to the input / output electrodes are formed in a substantially rectangular cross section.

The dielectric resonator according to claim 2 is characterized in that, in the invention according to claim 1, the inner conductor forming hole having a substantially rectangular cross section is arranged close to the input / output electrode forming surface side. It is what

[0010]

According to the above structure, since the inner conductor forming hole is formed in a substantially rectangular shape in cross section, the input / output electrode surface and the inner conductor surface can be formed as parallel surfaces. A large coupling capacitance is formed between the inner conductor and the corresponding inner conductor.

Further, by forming the inner conductor forming hole having a substantially rectangular cross section close to the input / output electrode forming surface side, a larger coupling capacitance is formed between the input / output electrode and the corresponding inner conductor. Is formed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A dielectric resonator according to an embodiment of the present invention will be described below with reference to the drawings. In the figure, the same parts are denoted by the same reference numerals, and the conductor forming portions are hatched in the perspective view.

FIG. 1 shows the structure of a dielectric resonator according to the first embodiment of the present invention. FIG. 1A is an external perspective view, and FIG. 1B is a sectional view taken along line XX of FIG. In the figure, the dielectric resonator is provided with two inner conductor forming holes 2 having a substantially rectangular cross section so as to penetrate between a pair of opposing surfaces of a substantially rectangular parallelepiped dielectric block 1. An inner conductor 3 is formed on the inner peripheral surface of each inner conductor forming hole 2. Further, a pair of input / output electrodes 4 are formed on a part of the outer peripheral surface of the dielectric block 1, and an outer conductor 5 is formed on the entire outer peripheral surface excluding the region where the input / output electrodes 4 are formed.

The inner conductor 3 is provided with a non-formed portion of the inner conductor 3 in the vicinity of one opening surface of the inner conductor forming hole 2, is released (separated) from the outer conductor 5, and is open at the other opening surface. Conductor 5
Is short-circuited (not shown).

The input / output electrode 4 is separated from the outer conductor 5 by providing a non-formed portion of the outer conductor 5 around the input / output electrode 4 and straddles one main surface (upper surface in the drawing) and side surfaces of the dielectric block 1. Has been formed.

When this dielectric resonator is mounted on a substrate, the surface on which the input / output electrodes 4 are formed (upper surface in the figure) is the substrate side.

In this structure, a coupling capacitance Ce is formed between the input / output electrode 4 and the inner conductor 3 corresponding thereto, as schematically shown in FIG. 1 (b).

As described above, the present invention is characterized in that the inner conductor forming hole is changed from the conventional circular cross section to the substantially square cross section, and other configurations are the same as those of the conventional example. It is composed.

As described above, since the inner conductor forming holes corresponding to the input / output electrodes are formed in a substantially quadrangular shape in cross section, the input / output electrode surface and the inner conductor surface can be constituted by parallel surfaces, and a circular cross section can be formed. It is possible to obtain a larger external coupling capacitance Ce as compared with the conventional dielectric resonator having the inner conductor forming hole.

Next, FIG. 2 shows the structure of a dielectric resonator according to a second embodiment of the present invention. The dielectric resonator according to this example has the same configuration as the dielectric resonator shown in FIG. 1, and the inner conductor forming hole having a substantially rectangular cross section in FIG. 1 is brought close to the input / output electrode forming surface side. It was formed. That is, the dielectric block 1 is formed by being offset toward one main surface or side surface or both surfaces thereof on which the input / output electrodes are formed.

In this structure, by making the input / output electrode surface and the inner conductor surface closer to each other, a larger external coupling capacitance Ce can be formed between the input / output electrode and the inner conductor.

In each of the first and second embodiments, the dielectric resonator having the two-stage resonator has been described. However, the number of resonator stages is not limited to this, and FIG. The one-stage resonator as shown, the three-stage resonator as shown in FIG. 4, or the four- or more-stage resonator may be used. Three
In the case of a resonator having more than one step, the inner conductor forming holes that do not correspond to the input / output electrodes may have a circular cross section. In short, the cross-sectional shape of the inner conductor forming hole corresponding to the input / output electrode that needs to have a large external coupling capacitance may be a substantially quadrangle.

Further, the input / output electrode formation position and the like are not limited to those in the embodiment, but may be formed only on one main surface or side surface of the dielectric block, for example. Further, the inner conductor and the outer conductor are also separated from each other by providing the non-formed portion of the inner conductor in the present embodiment, but the present invention is not limited to this, and the non-formed portion of the outer conductor is provided on a part or one surface of the outer conductor. Good.

Further, the present invention can be applied not only to the combline type as in the present embodiment but also to an interdigital type dielectric resonator.

[0025]

As described above, according to the dielectric resonator of the present invention, the input / output electrodes and the corresponding inner conductor forming holes are formed in a simple rectangular shape in cross section. A large coupling capacitance can be formed between the input / output electrode and the corresponding inner conductor without increasing the area of the output electrode and without increasing the sectional size of the inner conductor forming hole. Furthermore, by forming the inner conductor forming hole having a substantially square cross section close to the surface on which the input / output electrode is formed, a larger coupling capacitance can be formed between the input / output electrode and the inner conductor. Therefore, a dielectric resonator having a large external coupling capacitance and a high Qo can be obtained.

Therefore, when the dielectric resonator of the present invention is applied to a filter, a trap or the like, an external capacitor or the like is not required, the parts cost and the manufacturing cost can be reduced, and further, the filter and the trap can be reduced. It can also contribute to downsizing of the device.

[Brief description of drawings]

1A is an external perspective view of a dielectric resonator according to a first embodiment of the present invention, and FIG. 1B is a sectional view taken along line XX of FIG.

2A is an external perspective view of a dielectric resonator according to a second embodiment of the present invention, and FIG. 2B is a sectional view taken along line XX of FIG.

FIG. 3 is an external perspective view of a dielectric resonator including a one-stage resonator of the present invention.

FIG. 4 is an external perspective view of a dielectric resonator including a three-stage resonator of the present invention.

FIG. 5 is an external perspective view of a conventional dielectric resonator.

[Explanation of symbols]

 1 Dielectric block 2 Inner conductor forming hole 3 Inner conductor 4 Input / output electrode 5 Outer conductor

Claims (2)

[Claims] 1. A dielectric block is provided with at least one inner conductor forming hole, and an inner conductor is formed on an inner peripheral surface of the inner conductor forming hole so as to cover substantially the entire outer peripheral surface of the dielectric block. In a dielectric resonator comprising an outer conductor formed on the outer conductor and an input / output electrode capacitively coupled to the inner conductor in a part of the outer conductor, an inner conductor forming hole corresponding to the input / output electrode has a substantially rectangular cross section. A dielectric resonator characterized by being formed. 2. The dielectric resonator according to claim 1, wherein the inner conductor forming hole having a substantially quadrangular cross section is arranged close to a side on which an input / output electrode is formed.