JPH06215624A - High-frequency dielectric porcelain composition - Google Patents

Abstract

PURPOSE:To provide a high-frequency dielectric porcelain composition which has a high Q-value and at the same time excels in the temperature stability of a resonance frequency and has preferable characteristics to materials for a dielectric resonator, a dielectric substrate and the like. CONSTITUTION:MnCO3 and Ta2O5 are added at the rate of MnCo3: 0.5 parts by weight or less and Ta2O5: 1.0 part by weight to a composition containing BaO and TiO2 at the rate of Bad: 15 to 25% by mole and TiO2: 75 to 85% by mole. Further, for a material having perovskite structure, at least one kind selected from a group consisting of Ba(Zn1/3Nb2/3)O3, Ba(Mg2/3Nb2/3) O3, Ba(Mg2/3Ta2/3) O3, Ba(Zr, Zn, Ta)O3 and Ba(Sn, Mg, Ta)O3 is added thereto at 2 % by weight or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition, and particularly to a high frequency dielectric having preferable characteristics as a material for a dielectric resonator or a dielectric substrate used in a high frequency region such as a microwave region. It relates to a porcelain composition.

[0002]

2. Description of the Related Art High frequency dielectric porcelain compositions have been widely used as materials for dielectric resonators and dielectric substrates for high frequencies such as microwaves and millimeter waves.

This type of high frequency dielectric ceramic composition
As the material, for example, BaO-TiO For 2 materials,
As a perovskite-based material, Ba (Ni_1/3Ta_2/3)
O₃Of 0.2% by weight or less (Japanese Patent Laid-Open No. 62-16
5806) and BaO-TiO.₂For system materials,
As a composite perovskite material, Ba (Zn_1/3T
a_2/3) O₃In an amount of 0.3% by weight or less
No. 119957) is proposed.

However, in recent years, the demand for dielectric ceramic materials having a higher Q value has increased with the progress of higher frequency and narrower frequency bands used, and composite materials such as the above-mentioned dielectric ceramic compositions have been demanded. Even with a dielectric ceramic composition to which a perovskite-based material has been added, there are cases in which characteristics that satisfy the requirements in terms of Q value, temperature stability of frequency, etc. cannot always be obtained. Therefore, regarding the high frequency dielectric material, a material having a higher Q value than that of the conventional high frequency dielectric ceramic composition and having excellent temperature temperature stability has been demanded.

The present invention solves the above-mentioned problems, and is used as a material for a dielectric resonator, a dielectric substrate, or the like, which has a high Q value in the high frequency region and is excellent in the temperature stability of the resonance frequency. It is an object of the present invention to provide a dielectric ceramic composition for high frequency, which makes it possible to obtain a dielectric ceramic having preferable characteristics.

[0006]

In order to achieve the above object, the high frequency dielectric porcelain composition of the present invention comprises BaO and TiO ₂ of BaO: 15 to 25 mol% TiO ₂ : 75 to 85 mol%. MnCO ₃ and Ta ₂ O ₅ relative to the composition contained in proportion
Is added at a ratio of MnCO ₃ : 0.5 wt% or less Ta ₂ O ₅ : 1.0 wt% or less. Furthermore, as a material having a composite perovskite structure, Ba (Zn _1/3 Nb _2/3 ) O is added. ₃ Ba (Mg _1/3 Nb _2/3 ) O ₃ Ba (Mg _1/3 Ta _2/3 ) O ₃ Ba (Zr, Zn, Ta) O ₃ Ba (Sn, Mg, Ta) O ₃ It is characterized in that at least one selected from the above is added at a ratio of 2% by weight or less.

The MnC added in the present invention
O ₃ (Mn raw material) is Mn oxide (MnO ₂ , Mn) after sintering.
O, etc.). Therefore, instead of MnCO ₃ , any material that becomes a Mn oxide by sintering is used as a starting material (MnCO ₃ ).
It can be used as a raw material). In addition, MnO ₂
It is also possible to use Mn oxides such as the above as a starting material (Mn material). That is, MnCO ₃ added to the high frequency dielectric ceramic composition of the present invention is a broad concept including various Mn raw materials as described above. In addition,
In that case, the starting raw material (Mn raw material) is added at a ratio of 0.5% by weight or less when converted to MnCO ₃ .

[0008]

EXAMPLES Hereinafter, the features of the present invention will be described in more detail by showing examples of the present invention together with comparative examples.

First, as a raw material, high-purity BaCO ₃ ,
TiO ₂ , MnCO ₃ , and Ta ₂ O ₅ are prepared, and these raw materials are weighed so that the composition ratios shown in Table 1 are obtained.

[0010]

[Table 1]

In Table 1, the sample numbers marked with * indicate comparative examples outside the scope of the present invention, and the others indicate examples within the scope of the present invention.

Next, the weighed raw materials are put into a ball mill together with water and wet mixed for 16 hours to obtain a mixture. Then, this mixture is dried and then calcined at 1000 to 1200 ° C. for 3 hours to obtain a calcined body.

Then, a material having a composite perovskite structure as shown in Table 1 (composite perovskite material) is added to the calcined body, and the mixture is put in a ball mill together with water and an organic binder and wet mixed for 16 hours to be ground. .
Next, the obtained pulverized product of the calcined body is dried, and the particle size is adjusted through a 50-mesh sieve to obtain a powder (raw material powder) of the high-frequency dielectric ceramic composition.

Approximately 2500 kg of this raw material powder
After pressure-molding into a disk shape having a diameter of 12 mm and a thickness of 5.5 mm with a pressure of / cm ^2, the disk-shaped molded body is 1200 to 1400
A dielectric ceramic for high frequency (sample) is prepared by firing at 4 ° C. for 4 hours.

With respect to the sample thus obtained, the relative permittivity ε _r , the Q value, and the temperature coefficient τf (ppm / ° C.) of the resonance frequency at a frequency of 7 GHz were measured.

Table 1 shows the measurement results for the relative permittivity ε _r , the Q value, and the temperature coefficient τf (ppm / ° C.) of the resonance frequency.

From Table 1, in the high frequency dielectric porcelain composition of the example of the present invention to which an appropriate amount of the composite perovskite material was added, the relative permittivity ε _r , the Q value, and the resonance frequency in the high frequency region of 7 GHz. Temperature coefficient τf (ppm / ° C)
It can be seen that good results are obtained for each of the characteristics.

Next, the reason for limiting the composition range of each component will be described.

[Proportion of BaO and TiO ₂ ] Regarding the proportion of BaO and TiO ₂ which are the main components, the proportion of BaO is 1
Less than 5% by weight (ie 85% TiO ₂
If it exceeds 10% by weight), the Q value decreases, the temperature coefficient τf of the resonance frequency increases, and the proportion of BaO exceeds 25% by weight (that is, the proportion of TiO ₂ is 7%).
If it is less than 5% by weight), the Q value tends to decrease.
Therefore, the ratio of BaO and TiO ₂ is 15 for BaO.
˜25 mol% and TiO _{2 in} the range of 75 to 85 mol%.

When [MnCO ₃ ] MnCO ₃ is added in an amount exceeding 0.5% by weight, the Q value tends to decrease. Therefore, MnCO ₃ is preferably added in the range of 0.5 wt% or less.

If the amount of [Ta ₂ O ₅ ] Ta ₂ O ₅ added exceeds 1.0% by weight, the dielectric constant εr and the Q value decrease. Therefore, the addition amount of Ta ₂ O ₅ is preferably 1.0% by weight or less.

[Composite Perovskite Material] A composite perovskite material of Ba (Zn _1/3 Nb _2/3 ) O ₃ , B
a (Mg _1/3 Nb _2/3 ) O ₃ , Ba (Mg _1/3 Ta _2/3 )
O ₃ , Ba (Zr, Zn, Ta) O ₃ , and Ba (Sn,
Regarding Mg, Ta) O ₃ , when the addition amount exceeds 2.0% by weight, the dielectric constant εr tends to decrease, and the temperature coefficient τf of the resonance frequency tends to be too large on the plus side. The added amount is preferably 2.0% by weight or less.

[0023]

As described above, the high frequency dielectric of the present invention is used.
Body porcelain composition is BaO and TiO₂BaO: 15-2
5 mol%, TiO₂: Contained in a proportion of 75 to 85 mol%
MnCO₃And Ta₂O_FiveMnCO₃:
0.5% by weight or less, Ta₂O_Five: 1.0% by weight or less
And a material having a composite perovskite structure
As a charge, Ba (Zn_1/3Nb_2/3) O₃, Ba (Mg_1/3
Nb_2/3) O₃, Ba (Mg 1_{/ 3}Ta_2/3) O₃, Ba (Z
r, Zn, Ta) O₃, And Ba (Sn, Mg, Ta)
O₃2% by weight of at least one selected from the group consisting of
The microwave is added in the following proportions.
It has a high Q value in high frequency bands such as regions
And a dielectric resonator with excellent temperature stability of the resonance frequency
Dielectrics with desirable properties as materials for dielectric substrates
A high frequency dielectric porcelain composition capable of obtaining body porcelain
Obtainable.

Claims (1)

[Claims] 1. A composition containing BaO and TiO ₂ at a ratio of BaO: 15 to 25 mol% TiO ₂ : 75 to 85 mol%, MnCO ₃ and Ta ₂ O ₅
Is added at a ratio of MnCO ₃ : 0.5 wt% or less Ta ₂ O ₅ : 1.0 wt% or less. Furthermore, as a material having a composite perovskite structure, Ba (Zn _1/3 Nb _2/3 ) O is added. ₃ Ba (Mg _1/3 Nb _2/3 ) O ₃ Ba (Mg _1/3 Ta _2/3 ) O ₃ Ba (Zr, Zn, Ta) O ₃ Ba (Sn, Mg, Ta) O ₃ A dielectric ceramic composition for high frequencies, comprising at least 2% by weight of at least one selected from the above.