JPH0554718A - Dielectric porcelain composition for high frequency - Google Patents

Abstract

PURPOSE:To provide a dielectric porcelain composition for high frequency, the Q value of which is larger than that of conventional dielectric porcelain compositions, while providing a large dielectric constant and satisfactory temperature coefficient of a resonant frequency. CONSTITUTION:In a dielectric porcelain composition expressed by the formula: Ba(SnXMgYTaZ)OW (where X+Y+Z=1, W is an arbitrary number), the values X, Y, Z are respectively designed to be included within the region of molar ratio enclosed by the following four points: A(X, Y, Z), B(X, Y, Z), C(X, Y, Z), D(X, Y, Z), wherein A is (0.001, 0.360, 0.640), B(0.001, 0.300, 0.700), C(0.010, 0.300, 0.690), D(0.010, 0.360, 0.630).

Description

Detailed Description of the Invention

[0001]

The present invention relates to a dielectric ceramic composition,
In particular, the present invention relates to a high frequency dielectric ceramic composition used for a dielectric resonator or the like in a high frequency region.

[0002]

2. Description of the Related Art Dielectric ceramics are widely used in dielectric resonators, dielectric substrates, etc. in high frequency regions such as microwaves and millimeter waves. A high frequency dielectric ceramic composition of this type is disclosed in, for example, JP-A-60-1243.
No. 05, the formula: Ba (Sn _X
Mg _Y Ta _Z ) O _{7 / 2-X / 2-3Y / 2} , X, Y, Z
However, there are compositions in the range of 0.04 ≦ X ≦ 0.26, 0.23 ≦ Y ≦ 0.31, 0.51 ≦ Z ≦ 0.65 (where X + Y + Z = 1).

This conventional high frequency dielectric ceramic composition is
The dielectric ceramic composition has a large relative dielectric constant and a large Q value in a high frequency region and has a good temperature coefficient of resonance frequency.

[0004]

However, in recent years, there has been a tendency for the frequency range used to become higher, and dielectric ceramic compositions for dielectric resonators and dielectric substrates having a Q value as large as possible have been developed. These requirements have been met, and the above-mentioned conventional high-frequency dielectric ceramic composition cannot sufficiently meet the demand.

The present invention solves the above problems and has a higher Q value in a high frequency region than a conventional dielectric ceramic composition, and has a large relative permittivity and good resonance. An object of the present invention is to provide a high frequency dielectric ceramic composition having a temperature temperature coefficient.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have conducted diligent research and conducted research on Ba (Sn _X Mg _Y Ta
_{In the} composition represented by _Z ) O _W , the composition is adjusted so that X, Y and Z have a predetermined ratio,
The inventors have found that a high frequency dielectric ceramic composition having excellent characteristics such as Q value can be obtained, and completed the present invention.

That is, the dielectric ceramic composition for high frequency of the present invention has the formula: Ba (Sn _X Mg _Y Ta _Z ) O _W (however,
In the dielectric ceramic composition represented by X + Y + Z = 1, W = arbitrary number), X, Y, and Z are the four points A (X, Y, Z) and B (X, Y, Z) shown below, respectively. ), C (X, Y, Z), D
It is characterized by being in a molar ratio region surrounded by (X, Y, Z) A (0.001, 0.360, 0.640) B (0.001, 0.300, 0,700) C (0.010, 0.300, 0.690) D (0.010, 0.360) , 0.630).

In the high frequency dielectric ceramic composition of the present invention, the proportion of X, Y and Z is limited to the above range.
The composition outside the line connecting A and D shown in FIG. 1 (that is,
When Y> 0.36) and the composition outside the line connecting B and C (that is, Y <0.30), the sintering becomes unstable and a stable dielectric ceramic is obtained. In addition, when the composition outside the line connecting C and D in FIG. 1 (that is, X> 0.01), the obtained Q value is small, and outside the line connecting A and B in FIG. (For example, X
When <0.001), the Q value is small, and the temperature coefficient of the resonance frequency increases to the positive side, which is not preferable. The value of W varies somewhat depending on the ratio of X, Y, and Z, and for example, the formula: (7 / 2−X / 2−
3Y / 2).

[0009]

EXAMPLES Hereinafter, examples of the present invention will be shown together with comparative examples to clarify the characteristics of the invention.

The high frequency dielectric ceramic compositions of the examples and comparative examples of the present invention (that is, the formula: Ba (Sn _X Mg _Y Ta)
_Z ) O _W , a composition represented by
First, high-purity BaCO ₃ , SnO ₂ , MgCO ₃ , Ta ₂
O ₅ is prepared, these raw materials are weighed so as to have the composition shown in Table 1 below, put in a ball mill, and wet mixed for 16 hours. In addition, in Table 1, the values of X, Y, and Z indicate the molar ratios.

After drying the mixed raw material, 13
It is calcined at 00 ° C. for 3 hours to obtain a calcined product. Then, this calcined product is put into a ball mill together with water and an organic binder and wet-ground for 4 hours. After drying this crushed product, 5
The powder was adjusted to a predetermined particle size through a 0 mesh sieve, and the obtained powder was applied with a pressure of 2000 kg / cm ² and a diameter of 12 mm,
It is formed into a disc with a thickness of 5 mm. And this molded product 1
Each sample of the example and the comparative example was obtained by baking in the air at 600 ° C. for 20 hours.

The relative permittivity ε _r and Q value at a frequency of 10 GHz were measured for each sample of the example and the comparative example prepared as described above, and the temperature coefficient τ _{f of the} resonance frequency was calculated from the temperature change rate of the resonance frequency. Was calculated. The results are shown in Table 1.

[0013]

[Table 1]

In Table 1, the samples marked with * are samples outside the scope of the present invention, that is, comparative examples,
Others are samples within the scope of the present invention, that is, samples of Examples.

From Table 1, as shown in Sample No. 1, A in FIG.
Composition outside the line connecting D (that is, Y> 0.36)
In such a case, the sintering became unstable, a stable dielectric ceramic could not be obtained, and the characteristics could not be measured. This means that a dielectric ceramic (that is, a sintered body) that can be used as a high frequency dielectric ceramic cannot be obtained.

Also, as in the case of sample No. 5, when the composition outside the line connecting B and C in FIG. 1 (that is, Y <0.30), sintering becomes unstable like sample No. 1. Therefore, a stable dielectric ceramic could not be obtained and the characteristics could not be measured.

Further, like sample No. 9, C and D in FIG.
It can be seen that a sufficiently large Q value cannot be obtained with a composition outside the line connecting (i.e., X> 0.01).

In addition, as in Sample Nos. 2, 4, and 12, FIG.
Outside the line connecting A and B (ie, X <0.001)
, The Q value is small, and the temperature coefficient τ _{f of the} resonance frequency is
Is increased in the positive direction, which is not preferable.

On the other hand, sample Nos. 3, 6, 7, 8, 10, 1
1, 13, X, Y, and Z are the four points A,
The sample in the region of the molar ratio surrounded by B, C and D, that is, the sample within the range of the present invention has a higher Q value than the sample of the comparative example and has a good temperature coefficient of resonance frequency. It has τ _f , and the relative permittivity is equal to or higher than that of the comparative example, and it can be seen that it has a practically sufficient size.

[0020]

As described above, the high frequency dielectric ceramic composition of the present invention has X, Y, and Z values of the dielectric ceramic composition represented by Ba (Sn _X Mg _Y Ta _Z ) O _W. Is adjusted so as to be within a predetermined range surrounded by A, B, C, and D described above, so that it has a high Q value which cannot be obtained by the conventional dielectric ceramic composition and has a high Q value. A high frequency dielectric ceramic composition having a relative dielectric constant and a good temperature coefficient of resonance frequency can be obtained.

That is, according to the present invention, it is possible to provide a high frequency dielectric ceramic composition useful for applications such as a dielectric resonator and a dielectric substrate.

[Brief description of drawings]

FIG. 1 is a diagram showing a composition range of a high frequency dielectric ceramic composition of the present invention.

[Explanation of symbols]

 A, B, C, D Each point that defines the composition range, ..., Sample No.

Claims (1)

[Claims] 1. In a dielectric ceramic composition represented by the formula: Ba (Sn _X Mg _Y Ta _Z ) O _W (where X + Y + Z = 1, W = arbitrary number), X, Y and Z are respectively the following: 4 points A (X, Y, Z), B (X, Y,
Z), C (X, Y, Z), and D (X, Y, Z) in a molar ratio region, characterized by a high frequency dielectric ceramic composition A (0.001, 0.360, 0.640) B (0.001, 0.300, 0,700) C (0.010, 0.300, 0.690) D (0.010, 0.360, 0.630).