JPH11150407A - Small-sized resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably provide the small-sized resonator with high performance and high quality at low cost and facilitate the formation of a resonance conductor of the resonator for communication equipment. SOLUTION: A conductor 23 made of a wire or a foil of copper or silver or gold that is a noble metal is laminated by placing it between ceramic sheets. A small-sized resonator 31 is obtained by forming an inner electrode and an outer electrode on a surface of a dielectric body 33, that is sintered at a temperature of 1,200 deg.C or over and 1,350 deg.C or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric small resonator used for a dielectric filter of a mobile communication device, for example.

[0002]

2. Description of the Related Art Hitherto, a dielectric filter has been often used in a high frequency section of a mobile communication device, and this dielectric filter is generally formed of a coaxial λ / 4 dielectric resonator. .

FIG. 12 is a perspective view of a conventional coaxial λ / 4 dielectric resonator. In this coaxial type λ / 4 dielectric resonator, the dielectric material 2 is formed into a shape shown in the drawing by dry molding.
An outer conductor 1 and an inner conductor 3 having an inner diameter connected to the outer conductor 1 are provided, and a hole 6, an open portion 4, and a short-circuit portion 5 penetrating at the center are formed respectively.

On the other hand, as a resonator in which a conductive wire is embedded in a dielectric ceramic, there is a resonator described in, for example, JP-A-8-316711. FIG. 13 is a perspective view of the internal structure of a dielectric resonator showing a structure in which conductive wires are embedded in a dielectric. In FIG. 13, 131 is a dielectric ceramic, 132 is an external electrode formed on the surface of the dielectric ceramic 131, and 133 is a conductive wire. The dielectric resonator having such a configuration forms a porcelain material sheet formed by kneading a dielectric porcelain composition and a binder, and arranges conductive lines 133 at predetermined positions on the porcelain material sheet. Then, a ceramic material sheet is further stacked to form a laminate, cut into a predetermined shape, and fired at 900 to 1000 ° C. to form an external electrode 132 on the outer surface of the fired body, that is, the dielectric ceramic 131. A compact and high-performance dielectric resonator can be obtained.

[0005]

In the conventional coaxial .lambda. / 4 dielectric resonator, in order to reduce the size and height of the dielectric filter, the coaxial .lambda. / 4 dielectric resonator is replaced with a conventional coaxial .lambda. / 4 dielectric resonator. ×
1.5mm for 2mm or 1.7x1.7mm square shape
It is necessary to make the size of the square not more than mx 1.5 mm square.

However, in the one shown in FIG.
It is difficult to form a conductor because a plating solution does not enter the inside of the through hole 6 during the production or mass production of the die having the coaxial shape and the SIR shape. Further, the diameter of the hole 6 penetrated by dry molding is set to 1.0 mm.
The following molding involves variations in molding density due to raw material clogging during molding of the raw material. As a result, variation in quality becomes a serious problem, and it is difficult to provide a high-quality and inexpensive coaxial λ / 4 dielectric resonator.

Further, in the dielectric resonator to which the method of arranging the conductive lines 133 shown in FIG. 13 can be applied, the conductive lines are arranged in the unfired dielectric. Since the conductive wire itself shrinks during firing but does not shrink during firing, there is a problem that cracks are generated due to strain at the boundary surface between the dielectric and the conductive wire, resulting in poor quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to provide a high-performance, compact resonator that is compact, has excellent productivity and workability, is high quality, is inexpensive, and is suitable for mass production. Aim.

[0009]

The miniature resonator of the present invention comprises:
A ceramic sheet formed by a wet method and a conductor made of silver or gold of copper or a noble metal, a conductor is laminated in a ceramic sheet laminate,
It is characterized by being sintered at a sintering temperature of 350 ° C. or less.

According to this configuration, the coaxial shape or SIR
It is possible to obtain a high-quality, inexpensive, small-sized resonator that is easy to form a conductor, has no variation in molding density, and has excellent workability without cracks.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 comprises a ceramic sheet formed by a wet process and a conductor made of silver or gold of copper or a noble metal, wherein the conductor is laminated in a laminate of ceramic sheets; 1200 ° C or higher 1350
It is sintered at a sintering temperature of less than ℃, and the conductor inside the ceramic can be easily and reliably formed by inserting metal wires into the laminate of ceramic sheets for conductor formation. In addition, firing at 1200 ° C. or more and 1350 ° C. or less has an effect of eliminating cracking and peeling due to a difference in shrinkage between the noble metal and the ceramic.

According to a second aspect of the present invention, the conductor is provided with a portion having a different thickness in a part thereof. Since the conductor has a different thickness, the conductor becomes a resonator having an SIR structure, and the wavelength can be reduced. It has the action of:

According to a third aspect of the present invention, the conductor is a laminate of a precious metal foil of copper or silver or gold,
The use of a metal foil has an effect that processing is simple and an electrode can be formed in an arbitrary shape.

According to a fourth aspect of the present invention, the conductor is constituted by a metal wire of a noble metal of copper, silver or gold, and a homogeneous net covering the metal wire. Has the effect of increasing the adhesion strength at the interface with the ceramic and making it difficult to cause cracking and peeling.

According to a fifth aspect of the present invention, a metal wire made of a copper wire or a noble metal of silver or gold and a homogeneous metal wire spirally wound therearound are provided. By spirally winding a metal wire, the adhesive strength at the interface with the ceramic is increased, and cracking and peeling are less likely to occur.

According to a sixth aspect of the present invention, a dielectric paste of the same material as that of the ceramic sheet is applied to form a laminate of these ceramic sheets and the dielectric paste. By applying the dielectric paste to the metal sheet, there is an effect that the step between the metal wire and the ceramic sheet at the time of lamination is eliminated, and the occurrence of cracks and peeling can be suppressed.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1 is a diagram showing a manufacturing method for obtaining a small-sized resonator according to the present invention.
On a ceramic green sheet 21 having a diameter of 0.1 m, conductors 23 of noble metal wire or copper wire having a diameter of 0.1 mm to 1.0 mm are arranged at regular intervals, and on these conductors 23,
The ceramic green sheet 22 made of the same material as the ceramic green sheet 21 is stacked, and the compact resonator 31 shown in FIG. In FIG. 2, 32 is an external electrode, and 33 is a dielectric.

Here, the diameter of the conductor 23 of a noble metal wire or a copper wire is preferably 0.2 to 0.5 times the shape of the small resonator, that is, the sum of the thicknesses of the ceramic green sheets 21 and 22 shown in FIG. In consideration of the increase in the resistance of the conductor 23 and the increase in the conduction loss, the no-load Q of the small resonator can be maximized. As the noble metal wire used for the conductor 23, silver or gold having a low resistivity and a melting point of 1200 ° C. or less is preferable.

FIG. 2 is a perspective view of the small resonator according to the first aspect of the present invention. The compact of the small resonator manufactured by the manufacturing method of FIG. Dipped in the solution to attach silver and 6
The external electrodes 32 are formed at a temperature of 00 ° C. to 800 ° C. Although the example in which the external electrode 32 is formed by depositing silver in a silver solution has been described, the same effect can be obtained by forming the external electrode 32 by plating. The conductor 23 is made of a noble metal wire or a copper wire and has a function as a resonance conductor of the small resonator 31. As described with reference to FIG.
Sm-Ti ceramic green sheets 21 and 22 are laminated and fired together with the conductor 23 at a temperature of 1200 ° C. or more and 1350 ° C. or less, and have a relative dielectric constant of 81 and a wavelength shortening effect of 1/9 in a wavelength shortening rate. Have. The melting point is 96
In the case where silver having a melting point of 2 ° C., gold having a melting point of 1064 ° C., and copper having a melting point of 1083 ° C. are used as the conductor 23, the temperature is not lower than 1200 ° C.
By firing at 50 ° C., silver, gold and copper are liquefied at the sintering temperature of the dielectric 33 and the conductor 23 and the dielectric 33
No stress on the interface. In addition, 1200 ° C or more and 135
When baked at 0 ° C. or lower, silver, gold, and copper, which are conductors, become more dense and become thinner than the initial wire diameter when silver, gold, and copper are solidified again. It has the effect of suppressing stress on the body. Further, when firing at a temperature higher than 1350 ° C., the internal conductor 23 melts and disappears, and the function as a resonance conductor is lost.

When firing at a temperature lower than 1200 ° C., as shown in FIG. 3, cracks 41 are generated at the interface between the conductor 23 and the dielectric 33 due to the difference in contraction.

(Embodiment 2) FIG. 4 is a perspective view of a small resonator according to the second aspect of the present invention, in which portions having different wire diameters are provided within one continuous wire of a copper wire or a noble metal wire conductor 51. By providing a step, a difference in impedance can be provided at this step. As a result, an SIR structure is obtained, and an effect of shortening the wavelength can be provided. That is, in the example shown in the drawing, the conductor 51 has a structure in which conductors 51 having different wire diameters are laminated inside the dielectric 33 within one wire of the conductor 51.

Here, to shorten the wavelength, it is necessary to lower the characteristic impedance on the open end side where the electrostatic energy of the λ / 4 resonator is concentrated and increase the characteristic impedance on the short circuit side where the magnetic energy is concentrated. Therefore, FIG.
As shown in FIG. 4 (cross-sectional view of FIG. 4), by making the open-end-side conductor 61 thicker than the short-circuit-end-side conductor 62, the capacitance of the open-end-side conductor 61 on which electrostatic energy is concentrated is increased, and the characteristic impedance is increased. Make it smaller. Further, by making the short-circuit-side conductor 62 thin, the short-circuit-side inductance where magnetic energy is concentrated can be increased, and the characteristic impedance of the short-circuit-end conductor 62 is increased. By setting such characteristic impedance, the wavelength can be shortened and the resonator length can be shortened.

(Embodiment 3) FIG. 6 is a view showing an example according to the third aspect of the present invention, and FIG. 7 is an external perspective view of a small resonator formed by the foil of FIG. 71
Indicates that the ceramic green sheets 21 and 22 have the same overall size and are punched and laminated at the same time. Then, the ceramic green sheets 21 and 22 together with these laminates are cut into the shape shown in FIG. 6 and fired at a firing temperature of 1200 ° C. or more and 1350 ° C. or less to form the small resonator 81 shown in FIG. FIG. 7 shows a conductor 82 as a cut of the foil 71 shown in FIG. By adopting such a structure, the conductor 82 can be easily laminated by the same method as when the ceramic green sheets 21 and 22 are punched out, and since the foil 71 is punched and formed, the shape can be freely set and the design can be freely performed. The degree increases. That is, in the example shown in the figure, the conductor 82 which can be mass-produced and has stable quality is composed of the foil 71 and the ceramic green sheets 21 and 22.

(Embodiment 4) FIG. 8 is a view showing an example according to the fourth aspect of the present invention, wherein a copper wire or a noble metal silver coated with a copper or silver or gold net 93 which is a noble metal. FIG. 6 is a view showing a conductor 91 of a metal wire 92 made of any one of gold and gold. FIG. 9 is a view showing an example according to the fifth aspect of the present invention, in which a copper wire or a noble metal silver or gold metal wire 103 is spirally formed into a copper wire or a noble metal silver or gold metal wire 102. FIG. 3 is a view showing a conductor 101 wound around the slab.

FIG. 10 shows the respective conductors 9 of FIGS.
It is a perspective view when 1,101 are laminated | stacked. Conductor 91,
By laminating the conductor 111 on any one of the conductors 101, the adhesion at the interface between the dielectric 33 and the conductor 111 is increased, so that a small-sized resonator 110 with high reliability can be manufactured.

(Embodiment 5) FIG. 11 is a perspective view showing a small resonator 121 according to a sixth aspect of the present invention.

In FIG. 11, reference numeral 122 denotes a dielectric paste constituting the laminate, and a method for producing the paste will be described. First, a paste material is formed by dissolving 10 g of ethyl cellulose in a mixed solution of 45 g of terpineol (manufactured by Nippon Perfume Chemicals) and 45 g of mineral spirit A (manufactured by Nippon Oil Co., Ltd.). Next, as a dispersant, Tenlo 70 (manufactured by San Nopco Co., Ltd.) and TT
1 g each of S (manufactured by Ajinomoto Co.) is added and mixed. Further, 7 g each of the above terpineol and mineral spirit A and 19 g of the above prepared paste material are added and mixed to prepare a dielectric paste. Next, the small resonator 121 of FIG. 11 is obtained in the same manner as in the first embodiment. Here, the dielectric paste 122 is printed on the ceramic sheet 21 (see FIG. 1) by screen engraving, the conductors 23 are arranged, and the dielectric paste is printed thereon by screen engraving. It is desirable that the dielectric paste be laminated in a semi-dry state. Thereby, the dielectric paste 122 is filled in the gap formed on the boundary surface between the conductor 23 and the laminated surface of the two ceramic sheets 21 and 22 (see FIG. 1), and a laminated molded body in which the gap is filled can be manufactured. These laminated molded articles are heated at a temperature of
By firing at a temperature of 0 ° C. or lower, preferably 1300 ° C. for 4 hours, the small resonator 121 is obtained. 1350 ° C
When baked at a higher temperature, the vapor pressure rises and the internal conductor 2
3 evaporates and loses its function as a resonance conductor.
If it is fired at a temperature lower than 1200 ° C., cracks occur at the interface between the conductor 23 and the dielectric 33 due to the stress due to the difference in shrinkage as shown in FIG. By coating the dielectric paste on the conductor 23, the same effect as described above can be obtained without directly printing the dielectric 33 composed of the laminated ceramic sheets by screen plate making.

Table 1 shows the no-load Q values of the small resonator prepared by the above method and the conventional resonator.

[0029]

[Table 1]

[0030]

According to the miniature resonator of the present invention, when the conventional manufacturing method is downsized, there is a problem that the resonating conductor is not conducting, or a part of the electrode as the resonating conductor is not formed. However, these problems can be eliminated, and a small resonator can be easily manufactured. In addition, by using a foil as the resonance conductor, a resonance conductor having a shape that has not been obtained conventionally can be formed, so that the degree of freedom in designing the resonator can be greatly improved and downsizing can be easily achieved. More than 1200 ° C 1
By firing at 350 ° C. or lower, cracks and peeling which have conventionally occurred when a copper wire or a noble metal wire is buried in a laminate are eliminated, and a resonator excellent in quality can be produced. Has an effect. Further, in terms of characteristics, there is an effect that a small resonator having a large no-load Q and a small variation in resonance frequency with respect to a temperature change can be stably manufactured with high quality at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a manufacturing method for obtaining a small resonator according to the present invention.

FIG. 2 is a perspective view of the small resonator according to the first embodiment;

FIG. 3 is a perspective view of the small resonator according to the first embodiment;

FIG. 4 is a perspective view of a small resonator according to the invention of claim 2;

FIG. 5 is a sectional view of FIG. 4;

FIG. 6 is a diagram showing an example according to the invention of claim 3;

FIG. 7 is an external perspective view of a small resonator formed by the foil of FIG. 6;

FIG. 8 is a diagram showing an example according to the invention of claim 4;

FIG. 9 is a diagram showing an example according to the invention of claim 5;

FIG. 10 is a perspective view when the conductors shown in FIGS. 8 and 9 are stacked.

FIG. 11 is a perspective view showing a small resonator according to the invention of claim 6;

FIG. 12 is a perspective view of a conventional coaxial λ / 4 dielectric resonator.

FIG. 13 is a perspective view of the internal structure of a dielectric resonator showing a structure in which conductive wires are embedded in a dielectric.

[Description of Signs] 1,32,132 External electrode 2,131 Dielectric material 3 Inner diameter inner conductor 4 Opening part 5 Short circuit part 6,133 hole 21,22 Ceramic green sheet 23,51,82,91,101,111 Conductor 31, 81, 110, 121 Small resonator 33 Dielectric 41 Crack 61 Open end side conductor 62 Short end side conductor 71 Foil 92 Metal wire 93 Net 102 Metal wire 103 Metal wire 122 Dielectric paste 131 Dielectric ceramic

Claims (6)

[Claims] 1. A ceramic sheet formed by a wet process, and a conductor made of silver or gold of copper or a noble metal.
A small resonator characterized in that it is sintered at a sintering temperature of 200 ° C. or more and 1350 ° C. or less. 2. The small resonator according to claim 1, wherein the conductor has a portion having a different thickness in a part thereof. 3. The small resonator according to claim 1, wherein the conductor is a laminate of a precious metal foil of copper, silver or gold. 4. The small resonator according to claim 1, wherein the conductor comprises a metal wire of a noble metal of copper, silver or gold, and a homogeneous net covering the metal wire. 5. The small resonant circuit according to claim 1, wherein the conductor comprises a copper wire or a noble metal wire of silver or gold, and a homogeneous metal wire spirally wound therearound. vessel. 6. A laminate comprising a ceramic sheet and a dielectric paste formed by applying a dielectric paste of the same material as the ceramic sheet.
6. The small resonator according to any one of claims 1 to 5.