JPH0959059A - Conductor ceramic composition for microwave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a large conductivity by compounding a main component consisting of Li2 O, CaO, Pr6 O11 and TiO2 at specific ratios with one oxide selected from Bi2 O3 , SnO2 , MnO2 , Nb2 O5 and Ta2 O5 in a specified amount. SOLUTION: A main component consisting of Li2 CO3 , CaCO3 , Pr6 O11 , TiO2 , etc., is compounded with one oxide selected from Bi2 O3 , SnO2 , MnO2 , Nb2 O5 and Ta2 O5 , each in a specified amount. The mixture is subjected to wet blending by a ball mill, etc., and bried. Subsequently, the blended material is calcined at about 700-1000 deg.C for 1-5hr and pulverized. The mixed powder is compounded with an organic binder such as PVA and granulated. The granules are classified and formed under pressure. The forming is baked at about 1200-1400 deg.C for 1-5hr to obtain a composition expressed by the formula w.Li2 O-x.CaO-y.Pr6 O11 - z.TiO2 (0.0<w<=25.0mol%; 0.0<=x<=50.0mol%; 0.1<y<=30.0mol%; 0.1<z<=80.0mol%; w+x+y+z=100mol%). The material is compounded with Bi2 O3 , etc., in an amount of <=10 pts.wt. to obtain the objective conductor ceramic composition for microwaves.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dielectric ceramic composition, and relates to a technical field of a resonator used in a microwave region of several GHz band.

[0002]

2. Description of the Related Art In recent years, the high density of information has led to an increase in the frequency of signals used. For this reason,
For the resonators and filters for transmitters / receivers required as information transmission media, it is essential to use dielectric ceramic materials that have a sufficient function in the high frequency band.

Conventionally, this type of dielectric porcelain material includes:
BaO-Ti because the high frequency characteristics are relatively good
O ₂ system, Ba {Zn _1/3 (Nb ・ Ta) _2/3 } O ₃ system, or (Zr
・ Sn) TiO ₄ series is used.

However, in a resonator or the like made of this dielectric ceramic material, if the permittivity of this dielectric is ε, the wavelength of the electromagnetic wave propagating in the dielectric will be as short as 1 / √ε. Therefore, the larger the dielectric constant ε is, the smaller the dimensions of the resonator and the like can be.

On the other hand, such a dielectric ceramic material is
In practice, it is necessary to make the temperature coefficient τf of the resonance frequency as small as possible. Therefore, as a measure for making the temperature coefficient τf close to zero, a method of combining with a material having a large dielectric constant and a negative temperature coefficient τf is used.

However, in general, the larger the permittivity ε, the greater the temperature coefficient τf becomes, so that a suitable material having a large permittivity and a negative temperature coefficient τf cannot be found. In addition, it has been difficult to increase the Q value as a dielectric ceramic material for microwaves.

[0007] In recent years as a material for solving these _{problems, w · Li 2 O-x} · CaO-y · Sm 2 O 3 -z · TiO 2 dielectric ceramic compositions have been proposed. Regarding this dielectric porcelain composition, there is, for example, Japanese Patent Application No. 3-323237.

[0008]

[Problems that the Invention is to Solve this _{w · Li 2 O-x ·} C
_{aO-y · Sm 2 O 3} -z · TiO 2 composition but exhibit superior properties compared with previous materials, further characteristic improvement has been desired.

In view of the above points, the present invention has an object to obtain a dielectric ceramic composition having a large dielectric constant and Q value and a temperature coefficient τf of the resonance frequency close to zero.

[0010]

The feature of the dielectric ceramic composition for microwaves of the present invention is that the composition formula is w.Li.
_{2 O-x · CaO-y} · Pr 6 O 11 microwave dielectric ceramic composition represented by the -z · TiO ₂ At a, each w, x,
y and z are 0.0 mol% <w ≦ 25.0 mol% 0.0 mol% ≦ x ≦ 50.0 mol% 0.0 mol% <y ≦ 30.0 mol% 0.0 mol% < z ≦ 80.0 mol% w + x + y + z = 100 mol% as the main component, with Bi ₂ O ₃ , Sn
10% of any one of O ₂ , MnO ₂ , Nb ₂ O _{5 and} Ta ₂ O ₅
It is because it contained less than or equal to parts by weight.

[0011]

EXAMPLES In producing the dielectric ceramic composition for microwaves of the present invention, first, the raw materials Li ₂ CO ₃ and CaCO are used.
₃ , Pr ₆ O ₁₁ , TiO ₂ , and Bi ₂ O ₃ are prepared. Then, these are weighed and mixed so as to have a predetermined composition.

As an example, the composition ratios of Li ₂ O, CaO, Pr ₆ O ₁₁ and TiO ₂ are 9 mol% and 16 mol, respectively.
%, 12 mol% and 63 mol% are weighed and blended. Then, 3 parts by weight of Bi ₂ O ₃ is weighed and blended with this weighed material.

Next, this is 5-2 by a ball mill or the like.
After wet mixing with alcohol for 0 hours, 70
Calcination is performed at 0 to 1000 ° C. for 1 to 5 hours. Subsequently, this calcined product is pulverized again by a ball mill or the like for 2 to 50 hours.

Next, an organic binder such as polyvinyl alcohol is added to this, and the mixture is granulated and classified to 2000 to 300.
Molding is performed by applying a pressure of 0 kg / cm ² . Subsequently, this molded product is fired at a temperature of 1200 to 1400 ° C. for 1 to 5 hours, and then both surfaces are polished so that the thickness of the fired product becomes about ½ of the diameter, and a measurement sample is completed.

The sample thus completed is
The dielectric constant (ε), the Q value, and the temperature coefficient (τf) of the resonance frequency were measured near the measurement frequency of 3 GHz by using the Coleman method. The measurement results are shown in Tables 1 and 2. In addition, as the sample used for the description in the examples, sample No. 3 in Table 1 was used.
Corresponds to this.

[0016]

[Table 1]

[0017]

[Table 2]

As shown in the table, Bi ₂ O ₃ , SnO ₂ , Mn
It can be seen that by including O ₂ , Nb ₂ O ₅ or Ta ₂ O ₅ , the relative permittivity εr is slightly decreased, but the Q value is effectively increased. In particular, the Q value has a content of 3 to
It can be seen that the maximum value is shown in the vicinity of 5 parts by weight, while the value is rapidly decreased in the case of 10 parts by weight or more.

On the other hand, the temperature coefficient is as large as 60 ppm / ° C. when the above-mentioned inclusions are not included, but by including these inclusions, a good porcelain composition with a small temperature coefficient can be obtained. Is shown.

Therefore, when the dielectric ceramic composition for microwaves of the present invention is used in, for example, a resonator, it is appropriately selected in consideration of the above-described tendency when the amounts of these contents are changed. Will be used.

Further, when the dielectric ceramic composition for microwaves of the present invention is used for microwaves, especially when the Q value and the above temperature coefficient are important parameters in design, even if the dielectric constant is Even if the value of is small, it is practical.

In the present invention, Bi ₂ O ₃ , SnO ₂ , MnO ₂ , Nb ₂
O ₅ , Ta ₂ O _5, etc. were used, but in addition to these, magnesium oxide, cobalt oxide, nickel oxide, zinc oxide, tin oxide,
Examples include selenium oxide, tellurium oxide, thallium oxide, tungsten oxide, and rare earth oxides. These also have the same effects as MnO ₂ described in the examples.

In the present invention, Pr is used as a part of the main component.
_{Although 6} O ₁₁ was used, a similar effect can be expected for a composition using La ₂ O ₃ instead of ₆ O ₁₁ .

[0024]

According to the dielectric ceramic composition for microwaves of the present invention, lithium oxide (Li ₂ O) and calcium oxide (Ca
O), praseodymium oxide (Pr ₆ O ₁₁ ) and titanium oxide (TiO ₂ ) in a mixture of Bi ₂ O ₃ , SnO ₂ , MnO ₂ and Nb ₂
O ₅ or by incorporating 10 parts by weight or less of any one of Ta ₂ O _5, the relative dielectric constant εr and Q value is large,
Moreover, a small temperature coefficient τf can be obtained.

Therefore, the resonator or the like made of this composition can be downsized, and can be used with high reliability even in a situation where the temperature change is relatively large. Become.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Shibata 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A composition formula, At a microwave dielectric ceramic composition represented by _{w · Li 2 O-x ·} CaO-y · Pr 6 O 11 -z · TiO 2, each of w, x, y and z are 0.0 mol% <w ≦ 25.0 mol% 0.0 mol% ≦ x ≦ 50.0 mol% 0.0 mol% <y ≦ 30.0 mol% 0.0 mol% < z ≦ 80.0 mol% w + x + y + z = 100 mol% as the main component, with Bi ₂ O ₃ , Sn
10% of any one of O ₂ , MnO ₂ , Nb ₂ O _{5 and} Ta ₂ O ₅
A dielectric porcelain composition for microwaves, characterized in that it is contained in an amount of not more than part by weight.