JP3305009B2 - Dielectric 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 resonator and a dielectric filter which can be used for various radio devices or other communication devices.

[0002]

2. Description of the Related Art FIG. 9 is a diagram showing a conventional example.
FIG. 9A is an exploded perspective view of a dielectric filter, and FIG. 9B is a perspective view of a dielectric filter (an external view of a completed product). In FIG. 9, 1-
1-1 to 1-4 are dielectric layers, 3 is a GND electrode, and 4-1 to 4-
4 is a resonance conductor (resonance electrode), 5 is an input terminal (IN), 6
Indicates an output terminal (OUT), and 7 indicates a blank (portion where no conductor is formed).

Conventionally, as a dielectric filter using a dielectric resonator, a dielectric filter using a ceramic dielectric has been proposed. One example is shown in FIG. This dielectric filter is manufactured using a lamination technique of a ceramic multilayer substrate, and includes a ceramic dielectric as a first to a first dielectric filter.
This is an example using the fourth dielectric layers 1-1 to 1-4.

As shown in FIG. 9A, a first dielectric layer 1
-1, a GND electrode 3 is formed on the third dielectric layer 1
-4, four resonance conductors (resonance electrodes of a λ / 4 type resonator) 4-1 to 4-4 are formed on the lower side (outside) of the fourth dielectric layer 1-4. , The GND electrode 3 is formed.

The first to fourth dielectric layers 1-1 to 1-1
After laminating No. -4, the GND electrodes 3 are formed on all surfaces except for one surface of the laminate, as shown in FIG. 9B. G
An input terminal (I) is provided on one surface of the laminate in which the ND electrode 3 is not provided.
N) 5 and an output terminal (OUT) 6. in this case,
Since the input terminal 5 and the output terminal 6 need to be separated from the GND electrode 3, a margin 7 is provided between them.
Thus, a dielectric filter using the ceramic dielectric is obtained.

[0006]

The above-mentioned conventional apparatus has the following problems. (1) a dielectric resonator using a ceramic dielectric,
When manufacturing a dielectric filter, a firing step is required. For this reason, especially for thick ones, it takes time and effort to remove the binder.

(2) A dielectric resonator or a dielectric filter using a ceramic dielectric is a component that is heavier than other circuit components. (3) It is difficult to reduce the size (particularly in the thickness direction) without lowering the Q of the resonator.

In order to solve these problems, it has been considered to arrange a high dielectric substance around the resonance conductor and arrange a low dielectric substance outside the high dielectric substance. In this case, the combination of the high dielectric and the low dielectric which has been considered is as follows.

The high dielectric is made of ceramic and the low dielectric is made of ceramic. : The high dielectric is made of ceramic and resin, and the low dielectric is made of resin. : The high dielectric is made of resin and the low dielectric is made of resin.

However, the combination of such a high dielectric substance and a low dielectric substance causes the following new problem. (1) In the above combination, it is necessary to stack green sheets of different materials and fire them simultaneously. In this case, since the shrinkage ratio between the materials is different, it is difficult to control firing.

(2) The above combinations are as follows. That is, since a resin generally has a low dielectric constant, a resin in which ceramic powder is dispersed is used as a high dielectric substance.

However, even when such a material is used, the dielectric constant is lower than that in the case. Therefore, the wavelength cannot be sufficiently shortened. (3) In the above combination, it is as follows. That is, generally, resin has a low dielectric constant, and thus is not suitable as a high dielectric constant material.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, to realize a reduction in size and weight of a resonator and a filter, and to facilitate manufacture.

[0014]

FIG. 1 is an explanatory view of the principle of the present invention. In FIG. 1, the same components as those in FIG. 9 are denoted by the same reference numerals. Reference numeral 4 denotes a resonance conductor, 9-1 and 9-2 denote low dielectric layers (resins), 10-1 and 10-2 denote high dielectric layers (ceramics).

The present invention has the following configuration to solve the above problems. (1) A dielectric resonator in which a resonance conductor is set in a laminate obtained by laminating a plurality of dielectric layers, wherein the plurality of dielectric layers are formed of a resin low dielectric layer (dielectric constant ε ₂ ). , And a high-dielectric ceramic layer (dielectric constant ε ₁ ) (where ε ₁
> Ε ₂ ), both sides of the resonance conductor 4 (both sides in the stacking direction) are sandwiched between ceramic high dielectric layers 10-1 and 10-2, and both sides (both sides in the stack direction) are resin low dielectric layers. 9-
The layers were stacked so as to be sandwiched between 1, 9-2, and the GND electrodes 3 were set on both sides (both sides in the stacking direction).

(2) A dielectric filter in which a plurality of dielectric conductors having different resonance frequencies are set in a laminate obtained by laminating a plurality of dielectric layers, wherein the plurality of dielectric layers are formed of a resin low dielectric material. (Dielectric constant ε ₂ ) and a ceramic high dielectric layer (dielectric constant ε ₁ ) (however, ε ₁ > ε ₂ ), and both sides of a plurality of resonance conductors having different resonance frequencies (both sides in the stacking direction) ) Are replaced with the ceramic high dielectric layers 10-1 and 10-2.
And laminated on both sides (both sides in the laminating direction) so as to be sandwiched between the resin low dielectric layers 9-1 and 9-2.
Further, on both sides thereof (both sides in the stacking direction), GND electrodes (3)
It was set.

[0017]

The operation of the present invention based on the above configuration will be described with reference to FIG. In a resonator such as a dielectric resonator, the no-load Q (referred to as Qu) is generally defined by the following equation.

[0018]

(Equation 1)

Here, Qc is Q, Qd by the transmission line conductor.
Indicates Q by a dielectric, and Qr indicates Q by radiation. By the way, in a coaxial type resonator, 1 / Qr is usually ignored, so that the equation is as follows.

[0020]

(Equation 2)

Here, Qc is expressed by the following equation using the series resistance component r _S of the transmission line conductor and the line impedance Z ₀ of the transmission line.

[0022]

(Equation 3)

Further, Qd is expressed by the following equation by the relative dielectric constant ε _r ′ of the dielectric and the relative dielectric loss ε _r ″.

[0024]

(Equation 4)

From the above equation, to increase the no-load Q (Qu) of the resonator, it is necessary to (a) increase the line impedance Z ₀ and the relative permittivity ε _r ′. (B), reducing the series resistance component r _S and the relative dielectric loss ε _r ″.

In particular, if the relative permittivity ε _r ′ is increased, the wavelength is shortened as shown in the following equation.

[0027]

(Equation 5)

That is, the length of the resonance conductor of the λ / 4 type resonator becomes shorter due to the wavelength shortening shown by the equation. Therefore, the series resistance component r _S also decreases, and both Qc and Qd increase. As a result, the no-load Q (Qu) also increases.

In the dielectric resonator and the dielectric filter of the present invention, the resonance conductor 4 or a plurality of resonance conductors having different resonance frequencies are sandwiched between the high dielectric layers 10-1 and 10-2. The wavelength shown in the equation can be shortened.

Moreover, since the low dielectric layers 9-1 and 9-2 are interposed between the high dielectric layers 10-1 and 10-2 and the GND electrode 3, the thickness in the stacking direction is reduced. However, the capacitance C component does not increase. Therefore, the line impedance Z ₀ can be increased.

Accordingly, the Q of the resonance conductor 4 which is a transmission line conductor
(Qc) increases, and the no-load Q (Qu) also increases. That is, the size of the dielectric resonator and the dielectric filter can be reduced without lowering the Q.

Further, since the high dielectric layer is made of ceramics, a firing step is required. However, instead of simultaneous firing of different materials of a high dielectric constant material and a low dielectric constant material, which is conventionally considered, a single firing step is required. Since one material is fired, the firing process is relatively easy.

Further, since the low dielectric layer is made of a resin, a firing step is not required as in the case of ceramics, so that the low dielectric layer can be easily manufactured by injection or the like. And a dielectric filter can be realized.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. (1) Description of the first embodiment ... See FIGS. 2 to 6 FIGS. 2 to 6 are views showing a first embodiment of the present invention.
2 to 6, the same elements as those in FIGS. 1 and 50 to 58 are denoted by the same reference numerals. 10B is a ceramic fired body, 11 is an external terminal (side electrode), 11 is an external terminal (side electrode), 13 is an external electrode, 14 is a metal plate, 15 is a mold, 16 is an exterior resin, and 17 is a solder. Show.

The first embodiment is an example of a λ / 4 type (λ: signal wavelength) dielectric resonator, which will be described in detail below. (Description of Configuration of Dielectric Resonator)... See FIG. 2 FIG. 2A is a perspective view of the dielectric resonator, and FIG. 2B is a cross-sectional view taken along the line XY of FIG. 2A.

In this embodiment, a ceramic high dielectric layer (dielectric constant ε ₁ ) and a resin low dielectric layer (dielectric constant ε ₂ ) were used as dielectric layers (where ε ₁ > ε). ₂ ).
As shown in the figure, the dielectric resonator is provided with a resonance conductor (resonance electrode) 4 constituting a λ / 4-type resonator at the center in the longitudinal direction.

On both sides of the resonance conductor 4 (both sides in the stacking direction of the stacked body), a ceramic high dielectric layer 10-1 is formed.
10-2 is provided, and resin low dielectric layers 9-1 and 9-2 are provided on both sides (both sides in the stacking direction of the stacked body). In this case, it is desirable that the high dielectric layers 10-1 and 10-2 be formed thinner than the low dielectric layers 9-1 and 9-2.

The high dielectric layers 10-1 and 10-
2 and the outside of the stacked body composed of the low dielectric layers 9-1 and 9-2, except for the signal input terminal portion, the GND electrode 3 is formed, and the signal input terminal portion not forming the GND electrode is: An external terminal 11 is formed and connected to the internal resonance conductor 4.

In this case, a margin (portion where no conductor is provided) 7 is provided between the external terminal 11 and the GND electrode 3.
The external electrode 11 and the GND electrode 3 are prevented from contacting each other. With such a configuration, a dielectric resonator formed into an SMD (Surface Mount Component) is obtained.

(Description of Manufacturing Method of Dielectric Resonator)
FIGS. 3 to 6 are explanatory views of the manufacturing process of the dielectric resonator in the first embodiment. Hereinafter, a method of manufacturing the dielectric resonator will be described with reference to these drawings. In addition, S1 of FIG.
S7 indicates a process number (process number for explanation) of each manufacturing process.

Step S1: See FIGS. 3 and 4A First, a ceramic powder and a binder are mixed to form a slurry, and this is coated on a polyester film to produce a green sheet. That is, a green sheet constituting the high dielectric layers 10-1 and 10-2 shown in FIG. 2 is manufactured.

Step S2: see FIGS. 3 and 4A In this step, a conductor paste is applied to the green sheet by thick film printing to form the resonance conductor 4.

Step S3: see FIGS. 3 and 4B In this step, the green sheet is laminated with another green sheet so as to sandwich the resonance conductor 4, and hot-pressed to form a laminate.

Step S4: FIGS. 3, 4B and 5C
In this step, the laminate is removed from the laminate and fired to obtain a ceramic sintered body 10B. And the ceramic sintered body 10
The external electrode 13 is printed on the end where the B resonance conductor is exposed. Thereafter, as shown in FIG.
Next, the metal plate 14 is soldered with high-temperature solder.

Step S5: see FIGS. 3 and 5D In this step, the ceramic sintered body 10B provided with the metal plate 14 is inserted into a mold 15 and, for example, is formed by injection molding of a liquid crystal polymer. Apply resin around body. This resin is used for the low dielectric layers 9-1 and 9-9.
-2.

In this case, in the mold 15, the ceramic sintered body 10 B is made to have a structure in which the metal plate 14 is used as a pillar, and the periphery thereof is covered with a resin. : Step S6 ... See FIGS. 3 and 6E In this step, the resin portion formed in the above step, that is, the portion of the exterior resin 16 that is not plated is masked by a printing method or the like. Thereafter, the surface of the exterior resin 16 is etched with an acid or an alkali.

Step S7: FIGS. 3, 6F and 6G
In this step, the surface of the exterior resin 16 is plated.
Thereafter, as shown in FIG. 6G, the plated portion (GN
The D electrode 3) and the metal plate 14 on the GND side of the dielectric resonator are soldered, and the metal plate 14 is connected to the plating portion (the part to be the GND electrode 3) by solder 17. .

In this case, since the other metal plate 14 is used as the external terminal 11, a margin (a portion where no conductor is provided) 7 is formed around the other metal plate 14, and the plating portion (the GND electrode 3) is formed. And insulated.

Through the above steps, the dielectric resonator of the first embodiment can be manufactured. In addition, the manufacturing conditions of the above resin may be a resin having good workability at 200 ° C. to 300 ° C. and a relative dielectric constant of 5 or less.

The resin may be of any kind as long as it satisfies the above conditions. For example, PPS represented by epoxy resin and engineering plastic
(Poly-phenylene-sulfide), liquid crystal polymers, and the like.

(2) Description of the second embodiment: see FIGS. 7 and 8 FIGS. 7 and 8 show a second embodiment of the present invention.
7 is an exploded perspective view of the dielectric filter, and FIG. 8 is a perspective view of the dielectric filter (A is a view from the front side, and B is a view from the back side). 7 and 8, the same components as those in FIGS. 1 to 6 and 9 are denoted by the same reference numerals.

(Explanation of Configuration of Dielectric Resonator) FIG. 7 and FIG. 8 In the second embodiment, the resonance conductor forming the λ / 4 type resonator has four resonance conductors.
In this example, a dielectric filter (bandpass filter) is used.

As shown, the high dielectric layer (dielectric constant ε ₁ )
10-2, four resonance conductors (resonance electrodes) 4-1 and 4-
2, 4-3 and 4-4, and a high dielectric layer 10 is formed thereon.
-1 are laminated. Then, on both sides of these high dielectric layers (both sides in the stacking direction of the laminate), a low dielectric layer 9-1,
9-2 are laminated, and the GND electrodes 3 are formed on both sides thereof.

In this case, the four resonance conductors 4-1 and 4-
2, 4-3 and 4-4 have different lengths and different resonance frequencies. Also, the resonance conductor 4-1
One end (the end having a wider portion in the figure) of the reference numerals 4-4 is the GND side, and the other end is the signal input side.

In this way, the four resonance conductors 4-1 and 4-1
Both sides of 4-2, 4-3, and 4-4 (both sides in the stacking direction of the laminate) are sandwiched between the high dielectric layers 10-1 and 10-2, and both sides (both sides in the stacking direction of the laminate) are sandwiched. , Low dielectric layer 9-1,
9-2, and both sides thereof (both sides in the stacking direction of the stack) are sandwiched by the GND electrodes 3.

Then, except for one surface on the signal input side in the above-mentioned laminated body, the GND electrodes 3 are formed on all the remaining surfaces, and the input terminals (IN) 5 as external side electrodes are formed on the signal input surface. , An output terminal (OUT) 6 is formed.

In this case, since the input terminal 5 and the output terminal 6 are formed of a conductor having the same length as the thickness of the laminated body, a part of the GND electrode 3 around the input terminal 5 and the output terminal 6 is cut off, and a margin (a part without a conductor) is formed. ) 7 is formed in advance.

In this way, the input terminal 5 and the output terminal 6 can be prevented from coming into contact with the GND electrode 3. Also,
By providing such external terminals, it is possible to realize a dielectric filter formed as an SMD (Surface Mount Component).

(Description of manufacturing method of dielectric filter)
-See FIGS. 3 to 6 Since the dielectric filter of the second embodiment can be manufactured by the same manufacturing method (see FIGS. 3 to 6) as the dielectric resonator of the first embodiment, the description is omitted. However, it is necessary to set four resonance conductors having different resonance frequencies as the resonance conductor.

(Other Embodiments) Although the embodiments have been described above, the present invention can be implemented as follows. (1) In the dielectric filter of the second embodiment, the resonance conductor
However, the present invention is not limited to such an example, and an arbitrary number of resonance conductors may be used.

(2) The dielectric resonator of the above embodiment,
The outer shape of the dielectric filter is not limited to a square, but may be any shape.

[0062]

As described above, the present invention has the following effects. (1) A structure in which both sides of a resonance conductor are sandwiched between high dielectric layers, both sides of which are sandwiched between low dielectric layers, and both sides of which are sandwiched between GND electrodes, without lowering the Q value, The size of the dielectric filter can be reduced.

(2) Since only the high dielectric layer is made of ceramic, the firing step is compared with the case of simultaneous firing of different materials (simultaneous firing of the high dielectric layer and the low dielectric layer). It becomes easy.

(3) Since the low dielectric layer is made of resin, the weight of the dielectric resonator and the dielectric filter can be reduced as compared with the case where all of the low dielectric layers are made of ceramic. (4) Since the high dielectric layer is made of ceramic, it is easier to increase the high dielectric constant of the high dielectric layer than that made of resin.

(5) Since the low dielectric layer is made of a resin, the area around the high dielectric layer can be easily covered by, for example, injection. Therefore, the manufacture of the dielectric resonator and the dielectric filter becomes easy.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a diagram showing a dielectric resonator according to a first embodiment of the present invention.

FIG. 3 is an explanatory view (1) of a manufacturing process of the dielectric resonator according to the first embodiment of the present invention.

FIG. 4 is an explanatory view (2) of a manufacturing process of the dielectric resonator according to the first embodiment of the present invention.

FIG. 5 is an explanatory view (3) of a manufacturing process of the dielectric resonator according to the first embodiment of the present invention.

FIG. 6 is an explanatory view (No. 4) of a manufacturing process of the dielectric resonator according to the first embodiment of the present invention.

FIG. 7 is an exploded perspective view of a dielectric filter according to a second embodiment of the present invention.

FIG. 8 is a perspective view of a dielectric filter according to a second embodiment of the present invention.

FIG. 9 is an explanatory diagram of a conventional example.

[Explanation of symbols]

 3 GND electrode 4 Resonant conductor 9-1, 9-2 Low dielectric layer (resin) 10-1, 10-2 High dielectric layer (ceramic)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01P 1/00-9/00

Claims (2)

(57) [Claims] 1. A dielectric resonator in which a resonance conductor is set in a laminate obtained by laminating a plurality of dielectric layers, wherein the plurality of dielectric layers are formed of a resin low dielectric layer (dielectric constant ε ₂ ). And a ceramic high dielectric layer (dielectric constant ε ₁ ) (where ε ₁ > ε ₂ ), and both sides (both sides in the laminating direction) of the resonance conductor (4) are connected to the ceramic high dielectric layer ( 10-1 and 10-2), and both sides thereof (both sides in the stacking direction) are formed of a resin low dielectric layer (9).
-1, 9-2), and a GND electrode (3) on both sides thereof (both sides in the stacking direction).
A dielectric resonator characterized in that: 2. A dielectric filter in which a plurality of dielectric conductors having different resonance frequencies are set in a laminate obtained by laminating a plurality of dielectric layers, wherein the plurality of dielectric layers are formed of a resin low dielectric layer. (Dielectric constant ε ₂ ) and a high dielectric layer of ceramics (dielectric constant ε ₁ ) (where ε ₁ > ε ₂ ), and a plurality of resonance conductors (4-1, 4-2,
4-3, 4-4) on both sides (both sides in the laminating direction) are sandwiched between ceramic high dielectric layers (10-1, 10-2), and on both sides (both sides in the laminating direction) of resin low dielectric constant. Body layer (9
-1, 9-2), and a GND electrode (3) on both sides thereof (both sides in the stacking direction).
A dielectric filter characterized by setting: