JP2643634B2 - Dielectric coaxial resonator and dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric coaxial resonator and a dielectric filter using the same.

[0002]

2. Description of the Related Art When a dielectric filter is formed by using a plurality of dielectric coaxial resonators, a coupling terminal is inserted into a center hole of each dielectric coaxial resonator, and a coupling substrate is formed between adjacent coupling terminals. Connected through.

FIG. 12 shows an example of a band-pass filter in which dielectric coaxial resonators are connected in three stages.

In FIG. 12, R1 to R3 denote dielectric coaxial resonators, respectively, and 14 to 16 denote dielectric coaxial resonators R1 to R1.
This is a coupling terminal inserted into the center hole of R3. Also 17
Is a coupling substrate having three electrodes 18 to 20 formed on its surface, and 11 and 12 are input / output terminals connected to electrodes on the back surface side of the coupling substrate 17. Between the input / output terminal 11 and the coupling terminal 14, the electrode on the back side of the coupling substrate 17 and the electrode 1 on the front side
The coupling terminals 14 and 15 are coupled by the capacitance between the electrodes 18 and 19, and the coupling terminals 15 and 16 are similarly coupled by the capacitance between the electrodes 19 and 20. Is done.

Further, the coupling terminal 16 and the input / output terminal 12 are coupled by an electrostatic capacitance between an electrode on the back surface of the coupling substrate 17 and an electrode 20 on the front surface.

[0006]

However, when a dielectric filter or the like is constructed using a plurality of dielectric coaxial resonators as described above, a coupling terminal and a coupling substrate are required in addition to the dielectric coaxial resonator. However, there is a disadvantage that the entire size is increased. This is not limited to the case where a band-pass filter is configured, but is also the same when, for example, a band rejection filter is configured.

Further, each dielectric coaxial resonator can be miniaturized in the length direction by using a λ / 4 resonator, but the size is still determined in accordance with the dielectric constant and the resonance frequency of the dielectric, and furthermore, Could not be downsized.

An object of the present invention is to provide a dielectric coaxial resonator which is effective in reducing the number of parts and reducing the size by eliminating the need for a coupling terminal, a coupling substrate and a coupling element.

Another object of the present invention is to provide a dielectric coaxial resonator which can be reduced in size in the length direction as compared with the resonance frequency and is effective for miniaturization.

Another object of the present invention is to provide a smaller dielectric filter which is constituted by connecting a plurality of coaxial dielectric resonators without using a coupling terminal, a coupling substrate, or the like.

[0011]

[Means for Solving the Problems]

A dielectric coaxial resonator according to a first aspect of the present invention is a dielectric coaxial resonator having an inner conductor formed in a center hole of a dielectric and an outer conductor formed on an outer peripheral surface, An open surface having a surface continuous from the inner surface of the center hole,
A tongue-shaped projection thinner than the thickness of the inner surface and the outer peripheral surface, an electrode continuous from the inner conductor is formed on one surface continuous from the center hole of the projection, and an independent electrode is formed on the other surface. characterized in that the formation of the.

A dielectric coaxial resonator according to a second aspect of the present invention is a dielectric coaxial resonator in which an inner conductor is formed in a center hole of a dielectric and an outer conductor is formed on an outer peripheral surface. The center
Has a surface that is continuous from the inner surface of the hole and the outer surface.
A tongue-shaped protrusion is provided, and an electrode continuous from the inner conductor is formed on one surface of the protrusion, and an electrode continuous from the outer conductor is formed on the other surface.

[0014] The dielectric filter according to claim 3 further comprises:
A dielectric coaxial resonator according to claim 1 or 2 is arranged in parallel, and the protrusions of adjacent dielectric coaxial resonators are connected via a lead or a component.

[0015]

[Action]

In the dielectric coaxial resonator according to the first aspect of the present invention, the surface continuous from the inner surface of the center hole to the open surface of the resonator.
Having a thickness smaller than the thickness of the inner surface of the center hole and the outer peripheral surface.
Protrusions have tongue-like is that provided. And of the protrusion
An electrode continuous from the inner conductor is formed on one surface continuous from the center hole, and an independent electrode is formed on the other surface. Therefore, a capacitance is formed between the two opposing electrodes of the protrusion, and the relationship between the independent electrode formed on the protrusion and the resonator is equivalent to a circuit in which a capacitor is connected in series to the resonator. Become. Since the capacitor can be used as a coupling element with the resonator, a special capacitor as a coupling component is not required. Also the tongue
A continuous electrode from the inner conductor at the protrusion
Since the surface is a surface that is continuous with the inner surface of the central hole,
The poles can be easily formed. Further, the tongue-shaped projections
Is thinner than the thickness of the inner surface of the center hole and the outer peripheral surface.
Therefore, connection of components and leads can be easily performed.

In the dielectric coaxial resonator according to the second aspect, the open surface of the resonator is formed from the inner surface and the outer surface of the center hole.
Tongue-shaped projections having a continuous surface is al provided. So
Then , an electrode continuous from the inner conductor is formed on one surface of the protrusion, and an electrode continuous from the outer conductor is formed on the other surface. Since a capacitance is formed between the two opposing electrodes of the protrusion, a capacitor is equivalently connected between the inner conductor and the outer conductor (earth) at the open end of the resonator.

Assuming that the resonance frequency of the resonator is fo and the relative permittivity of the dielectric is εr, the resonator length X of the λ / 4 resonator is expressed by Equation 1.

[0019]

(Equation 1)

Here, if a capacitance C _A is added between the inner conductor at the open end of the resonator and the ground, the relationship expressed by Equation 2 holds when the length of the resonator at the same resonance frequency fo is X1.

[0021]

(Equation 2)

For example, fo = 900 MHz, εr = 90,
When Za = 10 and C _A = 10 pF, X = 8.778 mm and X1 = 5.902 mm. In addition, the tongue-shaped protrusions are
And surfaces that are continuous from the outer peripheral surface
Therefore, the molding of the dielectric can be easily performed, and the protrusion can be formed.
Of the inner conductor and the outer conductor
The subsequent electrodes can be easily formed.

In the dielectric filter according to the third aspect , the dielectric coaxial resonator having the configuration of the first or second aspect is arranged in parallel, and the protrusions of the adjacent dielectric coaxial resonator are connected via a lead or a component. ing. In the dielectric coaxial resonator having the configuration of claim 1 , since the capacitor is equivalently connected in series to the resonator, the electrodes formed on the protruding portions of the adjacent dielectric coaxial resonator are connected by the lead. The band-pass filter can be formed by simply performing the operation, and the band rejection filter can be easily formed by connecting the predetermined electrode portions formed on the protrusions with the coil.

In addition, when the dielectric coaxial resonator having the structure of claim 2 is used, not only is the resonator itself small, but also its protrusion is used as a mounting portion for connecting a capacitor or a coil. Therefore, the projections do not hinder miniaturization, and a small-sized dielectric filter can be configured as a whole.

[0025]

1 and 2 show the structure of a dielectric coaxial resonator according to a first embodiment of the present invention. 1 is an external perspective view, and FIG. 2 is a central vertical sectional view. As shown in both figures, a center hole 2 is formed at the center of a prismatic dielectric 1, an inner conductor 4 is formed on the inner surface of the center hole 2, and an outer conductor 3 is formed on the outer peripheral surface of the dielectric 1. I have. Also, a short-circuit electrode is formed on the surface indicated by B of the dielectric material, thereby forming a λ / 4 resonator having B as a short-circuit surface and A as an open surface.

On the open surface A side, the dielectric 1 is integrally formed.
One surface is continuous from the inner surface of the center hole, and
A tongue-shaped projection 1a thinner than the thickness of the surface and the outer peripheral surface is formed, and an electrode 4a continuous from the inner conductor 4 is formed on the upper surface (a surface continuous from the inner surface of the center hole) in the figure to extend. An independent electrode 5 is formed on the lower surface. Therefore, the independent electrode 5 is opposed to the electrode 4a which is continuous from the inner conductor via the projection 1a which is a dielectric, and a capacitance is formed therebetween. This constitutes a resonator in which a capacitor is equivalently connected in series to the inner conductor of the resonator. In addition, the electrode continuous from the inner conductor is
Since the electrode is formed on a continuous surface from the inner surface, it is easy to form the electrode.
Easy to do.

Next, FIG. 3 shows a structure of a dielectric filter according to a second embodiment, and FIG. 4 shows an equivalent circuit thereof. FIG.
, R1, R2 and R3 are the same dielectric coaxial resonators as those shown in FIG. C4 is a chip-shaped capacitor, which is mounted on the upper surface of the projection of the resonator R3, that is, on the electrode continuous from the inner conductor of the resonator R3. Further, the distance between the protrusions of adjacent resonators is 6, 7, 8,
They are connected via input / output terminals and leads shown at 9. Specifically, the input / output terminal 6 is connected to the independent electrode of the resonator R1, one end of the lead 7 is connected to the electrode 4a1 on the upper surface of the projection of the resonator R1, and the other end is the independent electrode of the projection of the resonator R2. And one end of the lead 8 is connected to the electrode 4 on the upper surface of the protrusion.
a2, the other end is connected to the independent electrode of the protrusion of the resonator R3, and one end of the input / output terminal 9 is connected to the upper electrode of the capacitor C4. Here, a tongue-shaped projection 1a
Thickness is smaller than the thickness of the inner and outer peripheral surfaces of the center hole.
The advantage that components and leads can be easily connected
There is.

With the above configuration, a three-stage band-pass filter as shown in FIG. 4 is formed.

Here, C1, C2 and C3 are capacitances formed on the projections of the resonators R1, R2 and R3, respectively.

Next, FIG. 5 shows a structure of a dielectric filter according to a third embodiment, and FIG. 6 shows an equivalent circuit thereof. In FIG. 5, R1, R2, and R3 are the same dielectric coaxial resonators as those shown in FIG. 1, and three dielectric coaxial resonators are arranged in parallel as shown in FIG.
One end of the input / output terminal 6 and one end of the coil L1 are connected to the electrode 4a1 of the protrusion of the resonator R1, and the other end of the coil L1 and one end of the coil L2 are connected to the electrode 4a2 of the protrusion of the resonator R2. The other end of the coil L2 and one end of the input / output terminal 9 are connected to the electrode 4a3 of the protrusion of the resonator R3. Thus, a three-stage band rejection type dielectric filter as shown in FIG. 6 is formed. Here, C1, C2, and C3 correspond to the capacitances formed on the protrusions of the resonators R1, R2, and R3, respectively.

Next, the structure of a dielectric coaxial resonator according to a fourth embodiment is shown in FIG. The difference from the dielectric coaxial resonator shown in FIG. 1 lies in that a cylindrical dielectric 1 is used and a center hole of a round hole is formed. As described above, the dielectric shape is not limited to the prismatic shape, and the band-pass or band-stop type dielectric filter as shown in FIG. 3 or FIG. Can be configured.

Next, the structure of a dielectric coaxial resonator according to a fifth embodiment is shown in FIGS.

FIG. 8 is a perspective view of the external appearance, and FIG. 9 is a vertical sectional view on the right side. As shown in both figures, a central hole 2 of a round hole is formed in a prism-shaped dielectric 1, an inner conductor 4 is formed in the center hole, and an outer conductor 3 is formed on the outer peripheral surface of the dielectric. The open surface A of the resonator
From the inner surface and the outer surface of the center hole 2
And an electrode 4a continuous from the inner conductor 4 is formed on the upper surface (a surface continuous from the inner surface of the center hole 2) in the drawing, and the lower surface (the outer surface) in the drawing is formed.
Electrode 3a continuous from outer conductor 3 on the surface (continuous from the peripheral surface)
Is formed. Therefore, as shown in FIG. 9, a capacitor is formed between the two electrodes 4a-3a facing each other via the projection 1a which is a dielectric, and the capacitor is formed on the open surface of the resonator by the inner conductor and the outer conductor (earth). Will be connected between them. This shortens the resonator length for obtaining the same resonance frequency as described above. Also, sudden
The raised portion 1a is connected from the inner surface and the outer peripheral surface of the center hole 2, respectively.
Shape having a continuous surface, that is, the thickness of the protrusion 1a
Since the inner and outer peripheral surfaces of the center hole 2 have the same thickness,
The molding of the conductor is easy and the upper surface of the projection 1a and
And an electrode 4a continuous from the inner conductor 4 to the lower surface and
A continuous electrode 3a can be easily formed from the outer conductor 3.

Next, FIG. 10 shows a structure of a dielectric filter according to a sixth embodiment, and FIG. 11 shows an equivalent circuit thereof. In FIG. 10, R1, R2 and R3 are the same dielectric coaxial resonators as those shown in FIG. Chip-shaped capacitors C1, C2, and C3 are mounted on the protrusions of the dielectric coaxial resonators. One end of the input / output terminal 6 and one end of the coil L1 are connected to the upper electrode of the capacitor C1. The other end of the coil L1 and one end of the coil L2 are connected to the upper surface electrode, and the other end of the coil L2 and one end of the input / output terminal 9 are connected to the upper surface electrode of the capacitor C3. As a result, a band rejection type dielectric filter as shown in FIG. 11 is formed.

In FIG. 11, C _A1 , C _A2 and C _A3 are capacitances formed on the projections of the resonators R1, R2 and R3, respectively.

Although the dielectric coaxial resonator shown in FIGS. 8 and 10 is an example in which a center hole of a circular hole is formed in a prismatic dielectric, the center of the square hole is formed in a dielectric of a prismatic shape. A hole may be formed.

[0037]

【The invention's effect】

In the dielectric coaxial resonator according to the first aspect of the present invention, since a capacitor connected in series to the inner conductor on the open surface is integrally formed, the capacitor is used for signal coupling with another resonator or the like. When configuring a dielectric filter or the like, the number of components can be reduced. The electrode continuous from the inner conductor is
The electrode is formed on a continuous surface from the inner surface of the
Easy. Furthermore, the thickness of the tongue-shaped protrusion is
Because it is thinner than the thickness between the inner surface and the outer peripheral surface,
Connection of components and leads to electrodes formed on the protrusions
Can also be easily performed.

[0039] In the dielectric coaxial resonator according to claim 2, Medium
Has a surface that is continuous from the inner surface and outer surface of the core hole
A tongue-shaped projection, and the center of the projection
Form an electrode that is continuous from the inner conductor on one side that is continuous from the hole.
And an electrode continuous from the outer conductor was formed on the other surface.
As a result, the capacitor connected between the inner conductor on the open surface and the ground is integrally formed, so that the resonator length for obtaining the same resonance frequency can be shortened, and a small-sized dielectric coaxial resonator can be obtained. Also, it continues from the inner surface of the center hole of the projection
A continuous electrode is formed on the surface from the inner conductor and continuous from the outer peripheral surface.
To form a continuous electrode from the outer conductor on the surface
Therefore, these electrodes can be easily formed. further,
The thickness of the tongue-shaped protrusion is defined by the difference between the inner surface of the center hole and the outer peripheral surface.
Since the thickness is the same as that between them, molding of the dielectric is also easy.

In the dielectric filter according to the third aspect , it is not necessary to form the capacitor by the coupling substrate, and the coupling terminal is not required, and the entire dielectric filter can be reduced in size.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a dielectric coaxial resonator according to a first embodiment.

FIG. 2 is a right side vertical sectional view of the dielectric coaxial resonator according to the first embodiment.

FIG. 3 is an external perspective view of a dielectric filter according to a second embodiment.

FIG. 4 is an equivalent circuit diagram of a dielectric filter according to a second embodiment.

FIG. 5 is an external perspective view of a dielectric filter according to a third embodiment.

FIG. 6 is an equivalent circuit diagram of a dielectric filter according to a third embodiment.

FIG. 7 is an external perspective view of a dielectric coaxial resonator according to a fourth embodiment.

FIG. 8 is an external perspective view of a dielectric coaxial resonator according to a fifth embodiment.

FIG. 9 is a right side vertical sectional view of a dielectric coaxial resonator according to a fifth embodiment.

FIG. 10 is an external perspective view of a dielectric filter according to a sixth embodiment.

FIG. 11 is an equivalent circuit diagram of a dielectric filter according to a sixth embodiment.

FIG. 12 is an external perspective view of a conventional dielectric filter.

[Explanation of symbols]

 1-dielectric 2-center hole 3-outer conductor 4-inner conductor 5-independent electrode 6-input / output terminal 7,8-lead 9-input / output terminal R-resonator A-open surface B-short-circuit surface

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-16802 (JP, A) JP-A-4-188902 (JP, A) JP-A-62-53804 (JP, U) JP-A-2-53804 130103 (JP, U) Japanese Utility Model 4-59603 (JP, U)

Claims (3)

(57) [Claims] 1. A dielectric coaxial resonator having an inner conductor formed in a center hole of a dielectric and an outer conductor formed on an outer peripheral surface, wherein the open surface has a surface continuous from the inner surface of the center hole. And said
A tongue-like projection that is thinner than the thickness between the inner surface of the center hole and the outer peripheral surface is provided .
Form a continuous electrode from the inner conductor on one side, and
A dielectric coaxial resonator formed with independent electrodes . 2. A dielectric coaxial resonator in which an inner conductor is formed in a center hole of a dielectric and an outer conductor is formed on an outer peripheral surface, wherein an open surface is respectively reached from the inner surface of the central hole and the outer peripheral surface.
A tongue-shaped protrusion having a continuous surface is provided, an electrode continuous from the inner conductor is formed on one surface of the protrusion, and
A dielectric coaxial resonator formed by forming a continuous electrode from an outer conductor . 3. The dielectric coaxial resonance according to claim 1 or 2.
And the adjacent dielectric coaxial resonator
That the projections are connected via leads or components
A dielectric filter characterized by the above-mentioned.