JPH06187828A - High frequency dielectric ceramic composition - Google Patents

Abstract

PURPOSE:To obtain a high dielectric constant and a Q value in a high frequency area and to allow the control of a Ta quantity and the free control of temperature property in a certain area by mixing BaO, MgO, WO3 and Ta2O5 at a specified ratio. CONSTITUTION:High frequency dielectric ceramic composition containing BaO, MgO, WO3 and Ta2O5 is formed of metal composite oxide as shown by a composition formula of xBaO.yMgO.zWO3.wTaO5/2 by mole ratio: x, y, z and w satisfy the formula. By changing these values within the composition formula, the temperature property of resonance frequency can be freely controlled in a certain area while loweres or sintering becomes difficult.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel high frequency dielectric ceramic composition having a high dielectric constant and a high Q value in a high frequency region such as a microwave and a millimeter wave.

[0002]

2. Description of the Related Art Dielectric ceramics are widely used for dielectric resonators, dielectric substrates for MICs, etc. in a high frequency range such as microwaves and millimeter waves.

Conventionally, as a dielectric ceramic of this type,
For example, ZrO ₂ —SnO ₂ —TiO ₂ -based material, BaO—
TiO ₂ materials, (Ba, Sr) (Zr, Ti) O ₃ based materials, Ba (Zn, Ta) O ₃ based materials and the like are known.

The above-mentioned material has a frequency of 10 due to various improvements.
The dielectric constant is 20 to 40, the Q value is 3000 or more at GHz, and the temperature coefficient (τf) of the resonance frequency is 0 ppm /
Excellent properties near ℃ have been achieved.

[0005]

Recently, the frequency to be used tends to be higher and the dielectric material is required to have more excellent dielectric properties, especially the Q value. However, in the above-mentioned conventional dielectric material,
At 10 GHz, even if the Q value is particularly increased, the limit is about 6000, and it is the current situation that these requirements cannot be sufficiently satisfied. Further, the conventional dielectric material cannot control the temperature coefficient (τf) of the resonance frequency.

An object of the present invention is to provide a dielectric porcelain composition which can meet such requirements, has a high dielectric constant and a high Q value in a high frequency range, and can control the temperature characteristic of the resonance frequency. It is what

[0007]

[Means for Solving the Problems] The inventors of the present invention have studied the above problems, and as a result, BaO, MgO, WO
It has been found that excellent dielectric properties can be obtained by containing ₃ and Ta ₂ O ₅ and adjusting these to a specific composition.

That is, the dielectric porcelain composition of the present invention is composed of a metal composite oxide and is composed of BaO, MgO, WO ₃ and Ta _2.
It is composed of O ₅ . The present invention provides a composition formula by molar ratio xBaO · yMgO · zWO ₃ · w
When expressed as TaO _5/2 , the x, y, z and w are

[0009]

[Equation 2]

The composition range is set to satisfy the above condition.

These ratios are set in the above range because the Q value decreases when the BaO amount (x) is less than 0.40 and the sintering becomes difficult, and the Q value decreases when it exceeds 0.55. Because. Further, if the MgO amount (y) is less than 0.10, the sinterability will be difficult or the Q value will be lowered, and if it is more than 0.40, the Q value will tend to be lowered. Furthermore, if the WO ₃ amount (z) is more than 0.30, the Q value will decrease. Also, the Q value decreases when the TaO _5/2 amount (w) becomes 0.40 or more.

And, in the dielectric ceramic composition of the present invention,
By changing the molar ratio of Ta ₂ O ₅ , BaO, MgO, and WO ₃ within the above range, it is possible to freely control the temperature characteristic of the resonance frequency in a fixed region while maintaining a high Q value.

Further, the reason for setting 0.20≤z + w≤0.40 is that when z + w is less than 0.2 or more than 0.4, the Q value is lowered or sintering is defective. is there.

In addition,

[0015]

[Equation 3]

The reason for this is that if the value is less than 0.17 or is 0.94 or more, the Q value is lowered and sintering becomes defective.

Further, Y, H is added to 1 mol part of this composition.
f, Zr, Mn, Sn, Ti, Ca, La, Ce, N
By adding at least one oxide of d, Pr, and Sm in the range of 0.3 parts by mole or less, the sinterability can be improved and the dielectric characteristics can be controlled.

As a method for producing a porcelain based on the present invention, for example, an oxide of Ba, Mg, W, Ta or a metal salt such as a carbonate or a nitrate which produces an oxide by firing is used as a raw material. Weigh it so that it falls within the specified range, and then mix thoroughly. Then, the mixture is 900-1
It is calcined at 300 ° C and crushed. Then, this calcined powder is molded into a predetermined shape by a molding method such as press molding or a doctor blade method.

Next, the molded body is fired at 1300 to 1600 ° C. in an oxidizing atmosphere such as the air to obtain a dielectric ceramic.

[0020]

In the dielectric ceramic composition of the present invention, BaO, Mg
By changing the molar ratio of O, WO ₃ , and Ta ₂ O ₅ , it is possible to freely control the temperature characteristic of the resonance frequency in a constant region while maintaining a high Q value. That is, as the Ta amount increases, the temperature coefficient τf tends to increase, and the temperature coefficient (τf) can be controlled. Hereinafter, the present invention will be described in the following examples.

[0021]

【Example】

Example 1 As raw materials, BaCO ₃ , MgCO _{3 having} a purity of 99% or more,
Using WO ₃ and Ta ₂ O ₅ powders, these are shown in Table 1.
Were weighed in the ratio shown in Table 1 and put into a ball mill lined with rubber together with water, and wet mixed for 8 hours. Next, this mixture was dehydrated and dried, and then calcined at 1000 ° C. for 2 hours, and the calcined material was wet-ground for 8 hours by adding water and an organic binder to a ball mill.

Thereafter, the pulverized product was dried and then granulated through a mesh of No. 50 mesh, and the obtained powder was 3000
It was molded into a cylinder having a size of 10 mmφ × 5 mmt at a pressure of kg / cm ² . Furthermore, this cylinder is 1400-16
Firing was performed under the condition of 00 ° C. × 6 hours to obtain a porcelain sample.

The relative permittivity (εr) and the Q value of the thus obtained porcelain sample at a frequency of 10 GHz were measured by the dielectric resonator method, and the temperature change of the resonance frequency in the temperature range from 25 ° C. to 85 ° C. The temperature coefficient (τf) of the resonance frequency was calculated from the ratio. The results are shown in Table 1.

[0024]

[Table 1]

According to Table 1, BaO, MgO, WO ₃ ,
Sample N in which the composition of Ta ₂ O ₅ deviates from the scope of the present invention
o. 4,8,11,12,18,22,25,26,2
In Nos. 7 and 28, the Q value was 1200 or less, or sintering failure occurred. On the other hand, the sample of the present invention has a relative dielectric constant of 10 or more,
A Q value of 3000 or more was achieved, and when the compounding amount of Ta ₂ O ₅ was changed, the temperature characteristic of the resonance frequency was -28 to 13 ppm.
It is understood that the temperature fluctuates up to / ° C.

Example 2 As raw materials, BaCO ₃ , MgCO _{3 having} a purity of 99% or more,
Using WO ₃ and Ta ₂ O ₅ powder, the material No. 2,
7 and 10 were weighed, and Y ₂ O ₃ , HfO ₂ , ZrO ₂ , MnO ₂ and Sn were added to 1 mol part of the main component composition.
O ₂ , TiO ₂ , CaO, La ₂ O ₃ , CeO ₂ , Nd
_At least one kind of powder of ₂ O ₃ , Pr ₆ O ₁₁ and Sm ₂ O ₃ was weighed in a ratio shown in Table 2, put in a ball mill lined with rubber together with water, and wet mixed for 8 hours. Next, this mixture was dehydrated and dried, and then calcined at 1000 ° C. for 2 hours, and the calcined material was wet-ground for 8 hours by adding water and an organic binder to a ball mill.

Thereafter, the pulverized product was dried and then granulated through a mesh of No. 50 mesh, and the obtained powder was 3000
It was molded into a cylinder having a size of 10 mmφ × 5 mmt at a pressure of kg / cm ² . Furthermore, this cylinder is 1400-16
Firing was performed under the condition of 00 ° C. × 6 hours to obtain a porcelain sample.

With respect to the thus obtained porcelain sample, the relative permittivity (εr) and the Q value at a frequency of 10 GHz were measured by the dielectric resonator method, and the temperature change of the resonance frequency in the temperature range from 25 ° C to 85 ° C was measured. The temperature coefficient (τf) of the resonance frequency was calculated from the ratio. The results are shown in Table 2.

[0029]

[Table 2]

According to Table 2, Y, Hf,
Zr, Mn, Sn, Ti, Ca, La, Ce, Nd, P
Even if at least one of the oxides of r and Sm is added in an amount of 0.2 mol parts or less, a high Q value of 3000 or more is obtained, and at the same time, the resonance frequency temperature characteristic is ± 30 ppm / ° C.
It can be seen that the value can be controlled to any value within the range.

[0031]

As described above in detail, according to the present invention, B
By blending aO, MgO, WO ₃ and Ta ₂ O ₅ in a predetermined ratio, it is possible to obtain a high dielectric constant and a Q value in a high frequency region, and by controlling the Ta amount, the temperature characteristics can be controlled in a constant region. You can control it freely. As a result, it can be sufficiently applied to various resonator materials used in the microwave and millimeter wave regions, dielectric substrate materials for MIC, and the like.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Gentaro Kaji, 1-4 Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Stock Company Research Institute

Claims (1)

[Claims] 1. A composition formula containing BaO, MgO, WO ₃ and Ta ₂ O ₅ and having a molar ratio of xBaO.yMgO.z.
When expressed as WO ₃ wTaO _5/2 , the above x, y, z, w
Is [Equation 1] A dielectric ceramic composition for high frequency, characterized in that: