JPH10190325A - Dielectric resonator and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably provide a small-sized low-height molding, to perform sintering even at the temperature of fusing a metallic material to be an inner conductor and to provide a high dielectric constant and a high Q value. SOLUTION: The mixture of dielectric material powder and a binder whose main component is an organic high polymer compound and the mixture of metal powder and the binder whose main component is the organic high polymer compound are simultaneously extruded. Thus, a small-sized low-height sintered compact 1 provided with an open terminal 2 and a short-circuit terminal 3 on both ends for which an outer conductor 5 is executed to an outer surface and the inner conductor 4 is executed to an inner surface excluding both ends is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator mainly used for a microwave filter, a microwave oscillator, and the like mounted on a mobile communication device and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A conventional technique will be described below.

In recent years, with the progress of communication technology, mobile phones,
Mobile communication systems such as PHS and GPS (Global Pos
itioning System) is rapidly spreading. for that reason,
The frequency band used for communication has been expanded, and the use in the microwave band has become active.

[0004] However, in such a communication system, since various systems are used, discrimination of the frequency between the systems becomes a serious problem.

A coaxial dielectric resonator using a dielectric ceramic for this frequency discrimination has advantages in that the resonance frequency can be freely set according to the length of the resonator itself and that it can cope with a high frequency band of 1 GHz or more. Yes, demand can be expected to increase in the future.

Recently, circuit components have been actively reduced in size and thickness and are being put to practical use. Along with this, a small and low-profile dielectric resonator has been required.

[0007]

However, the dielectric material having the maximum dielectric constant is about 115,
Transverse Electric and used in 00MHz band
Magnetic (TEM) dielectric resonators are generally
When the axial length is about three times or more of one side, it is difficult to perform molding by the uniaxial press molding method, so that there is a problem that the yield is extremely reduced.

That is, as shown in FIG. 2, an open end 2 and a short-circuit end 3 are provided at both ends of a prism, a through hole 6 is provided in a central axis direction, and an internal conductor 4 is formed on the inner periphery of the through hole. In the case of a coaxial dielectric resonator in which the outer conductor 5 is provided on the outer periphery of the four surfaces excluding both ends of the prism, when a molded body is obtained by using the conventional uniaxial press molding method, the pin forming the through hole is thin and the pin is short. Is bent or broken, and a compact and low-profile molded body cannot be obtained.

In a dielectric resonator having a shape as shown in FIG. 2, since the conductor and the dielectric resonator are simultaneously sintered, a dielectric material which can be sintered at a temperature lower than the melting point of the conductor is usually used. Is required.

However, such a dielectric material which can be sintered at a low temperature has a drawback that the dielectric constant and the Q value are deteriorated as compared with ordinary dielectric materials.

Therefore, the technical problem of the present invention is to provide a compact, low-profile molded product that can be stably obtained even at a temperature at which a metal material serving as an internal conductor melts, has a high dielectric constant,
An object of the present invention is to provide a dielectric resonator capable of obtaining a high Q value and a method of manufacturing the same.

[0012]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors paid attention to a two-color extrusion molding method used for molding plastics, and as a result of various studies,
It has been found that the above problem is solved by using an extruder in which a feed block is provided between an adapter of a conventional extruder and a flat die.

[0013] That is, since the slurry flow can be extruded by the feed block at an appropriate ratio and in order, a multilayer sheet can be obtained. Since the conductive paste can be filled, the pin portion is not bent or broken at all, and it has been found that a small, low-profile molded product can be stably obtained.

Moreover, when a molded body for a dielectric resonator is obtained by using a two-color extruder, the portions of the molded body where the paste for the internal conductor has flowed are extremely thin and thick at the center axis. Therefore, it was found that the sintering was not affected by the sintering temperature. Therefore, after sintering, both ends of the columnar molded body can be cut out to obtain a predetermined resonator shown in FIG.

Therefore, a dielectric resonator having a high dielectric constant and a high Q value can be obtained even at a temperature at which the metal material serving as the internal conductor melts.

That is, according to the present invention, in a dielectric resonator in which one end of a columnar member has a short-circuited end on a surface opposite to an open end and an external conductor is provided on the other surface except the both ends, A dielectric resonator characterized in that the shaft center is filled with an internal conductor is obtained.

According to the present invention, a slurry containing a dielectric material powder and an organic polymer compound as main components and a paste for an internal conductor containing a metal powder and an organic polymer compound as main components are simultaneously extruded, A method for manufacturing a dielectric resonator, characterized in that a center axis portion is filled with an internal conductor and a molded body in which the periphery of the internal conductor is filled with the slurry is sintered.

Further, according to the present invention, there is provided a method for manufacturing a dielectric resonator, characterized in that a two-color extrusion molding method is used in the method for manufacturing a dielectric resonator.

When Ag, which has a relatively low melting point, is used as the metal material serving as the internal conductor, 1200 mm is used as the dielectric material.
BaO-TiO ₂ sinterable at about 1350 ° C, B
aO-TiO ₂ -rare earth oxide, BaO-TiO ₂ -B
i ₂ O ₃ -Rare earth oxide type, BaO-TiO ₂ -Bi ₂ O ₃
-PbO-rare earth oxide system (the rare earth is La, Ce,
Compounds such as Pr, Nd, Sm, Eu, and Gd) can be used.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a dielectric resonator according to the present invention will be described in detail.

First, BaO—Sm ₂ O ₃ —Bi ₂ O ₃ —Ti
A calcined powder of an O ₂ -based dielectric material was obtained by a usual powder metallurgy method.

Next, this calcined powder is 90 wt%, melting point 60
6% by weight of paraffin wax at ℃, average molecular weight of about 16
2% by weight of low-density polyethylene having a molecular weight of about 0000, 11% vinyl acetate content and an average molecular weight of about 110,000.
After weighing each so that the vinyl acetate copolymer was 2 wt%, the mixture was kneaded with a pressure kneader at 130 ° C. for 1 hour to obtain a slurry mainly composed of a dielectric material powder and an organic polymer compound.

The slurry was formed into pellets having a diameter of 4 mm and a length of about 5 mm by an extruder equipped with a rotary blade, and used as raw materials for molding.

Using this raw material, an Ag paste for an internal conductor composed of a metal powder and an organic polymer compound, one of two feed ports of a feed block of a two-color extruder was used to
Extrude slurry of dielectric material powder and organic polymer compound,
The other extruded a slurry of Ag paste into the center axis.

The compact thus obtained is somewhat larger in size than the sintered compact of FIG. In particular, although not shown, a molded body having an inner conductor filled with Ag paste at both ends was not shown, but the injection port was small and spread toward the inside.
Is slightly different from the shape of

When obtaining the sintered body of FIG. 1, both end faces having an injection port of the molded body are cut off. At the time of sintering, the obtained molded body is processed without cutting off both end faces.
Therefore, since the inlets of the internal conductors at both end surfaces are very small, the influence of the sintering temperature is extremely small.

Further, the above-mentioned molded body was inserted into a degreasing furnace, and heated in the atmosphere from room temperature to 400 ° C. at a rate of 20 ° C./hour to perform degreasing.

By sintering the degreased body in the air at a temperature of 1300 ° C. for 2 hours, both ends of the sintered body are cut, processed into a predetermined size, and the length h, width a, length l A sintered body having the dimensions shown in Table 1 having a filled long-axis internal conductor having a rectangular cross section (consisting of vertical d and horizontal b) at the center axis was obtained.

[0029] * _Fr is the resonance frequency.

Next, C is formed on the sintered body as an external conductor.
After forming the u-plated layer, the plating film on one cross section was scraped off to obtain a sample shown in FIG.

Next, the Q value was measured with a network analyzer. Note that the Q value of the dielectric resonator is required to be large.

For comparison with the product of the present invention, a sample of a conventional product was obtained as follows.

A powder of a BaO—Sm ₂ O ₃ —Bi ₂ O ₃ —TiO ₂ based dielectric material was obtained by a usual powder metallurgy method.

Next, after pressing this powder, it was sintered in air at a temperature of 1300 ° C. for 2 hours to obtain a sintered body having the dimensions shown in Table 2.

[0035] * _Fr is the resonance frequency.

Next, after forming a Cu plating layer as an outer conductor and an inner conductor of the sintered body, the plating film of one cross section was scraped off to obtain a sample shown in FIG.

Next, the Q value was measured by a network analyzer.

As is apparent from these results, by using the two-color extrusion molding method for molding, a compact, low-profile dielectric resonator molded body that could not be obtained by the conventional uniaxial press molding method. Can be obtained stably, and
A comparable Q value can be obtained as compared with a sample manufactured by a uniaxial press molding method.

[0039]

As described above, according to the present invention,
By using a two-color extrusion molding method for molding, it is possible to stably obtain a compact, low-profile molded body of a dielectric resonator that could not be obtained by a uniaxial press molding method, and
Since it is possible to provide a dielectric resonator which can be sintered even at a temperature at which a metal material serving as an internal conductor is melted, obtain a high dielectric constant and a high Q value, and a method of manufacturing the same, a circuit miniaturization which is expected to proceed further in the future It can be made thinner and has great industrial value.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a molded body used for a dielectric resonator of the present invention.

FIG. 2 is a perspective view showing a molded body used for a conventional dielectric resonator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sintered body 2 Open end 3 Short-circuit end 4 Inner conductor 5 Outer conductor 6 Through hole

Claims (3)

[Claims] 1. A dielectric resonator having one end of a columnar member having a short-circuited end on a surface facing an open end and an outer conductor provided on another surface excluding the both ends, wherein an inner conductor is provided on a center axis portion. A dielectric resonator characterized by being filled with: 2. A slurry containing a dielectric material powder and an organic polymer compound as main components and a paste for an internal conductor containing a metal powder and an organic polymer compound as main components are simultaneously extruded and formed into a central axis portion. A method for manufacturing a dielectric resonator, comprising: sintering a molded body in which a conductor is filled and a periphery of an inner conductor is filled with the slurry. 3. The method for manufacturing a dielectric resonator according to claim 2, wherein a two-color extrusion molding method is used.