JP2002145662A - Dielectric porcelain composition for microwave - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dielectric porcelain composition having a large dielectric constant ε, a temperature coefficient τf of resonance frequency close to 0, and a large Q value by adding and blending a dielectric porcelain composition having a large positive temperature coefficient τf of resonance frequency to a dielectric porcelain composition having a large negative temperature coefficient τf of resonance frequency. SOLUTION: In a dielectric porcelain composition expressed by compositional formula: (Li1+1/2.R3+1/2).TiO2, wherein R3+ is one or more selected from La3+, Nd3+, and Sm3+, a specific amount of Bi3+ is incorporated as a portion of the amount of the R3+, thereby, a dielectric constant ε larger than that of the dielectric porcelain composition above can be obtained and the temperature coefficient τf of resonance frequency becomes large, and further, it is possible to control the temperature coefficient τf of resonance frequency, e.g. to bring the value of τf close to 0 by substituting a portion of Li1+ with Na1+.

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 for microwaves used for a resonator material or a capacitor material used in a microwave range of several GHz.

[0002]

2. Description of the Related Art In recent years, dielectrics have been used for resonators, filters, and capacitors used in transceivers such as satellite communication broadcasting utilizing microwaves in the several GHz band or mobile object identification devices.

Conventionally, this type of dielectric porcelain material includes:
For example, BaO-TiO_Two-Nd_TwoO _Three-Bi_TwoO_ThreeSystem composition
An article has been proposed (JP-A-61-8806).
The composition has a dielectric constant ε of about 70 to 110,
When configuring an electronic resonator or capacitor, the dielectric constant
The larger the material used, the smaller the size of the resonator
Therefore, a material having a larger dielectric constant ε is desired.
You.

Conventionally, materials having a large dielectric constant ε include, for example, SrTiO ₃ , CaTiO _3, etc., whose dielectric constants ε are very large, 300 and 180, but whose temperature coefficient τf of the resonance frequency is +1700 ppm / ° C. And + 800p
It cannot be used because it is very large at pm / ° C.

Therefore, the temperature coefficient τ of the dielectric ceramic composition
As a method of lowering f, there is a method of combining a material having a dielectric constant ε as large as possible and a temperature coefficient τf having a negative value. Temperature temperature coefficient τf
Is obtained.

[0006]

For example, Japanese Patent Application Laid-Open No. H5-25-2
No. 11009 discloses that the dielectric constant ε is large and the temperature coefficient τ
As a material having a negative value of f, the composition formula is (A ¹⁺
_1/2 · B ³⁺ _1/2 ) TiO ₃ , where A ¹⁺ is Li ¹⁺ , B ³⁺
By combining materials that are Nd ³⁺ , Sm ³⁺ , Co ³⁺ or Pr ^3+, it is possible to obtain a porcelain composition having a large dielectric constant ε and a temperature coefficient τf of resonance frequency close to 0. Proposed.

However, today, there is a strong demand for miniaturization of portable electronic terminal equipment, and the use of a material having a higher dielectric constant ε for a dielectric of a resonator, a filter, and a capacitor used in such equipment has been required. Is strongly required.

In view of the characteristics required for a dielectric ceramic composition for microwaves, the present invention provides a temperature coefficient τf of the resonance frequency.
The dielectric constant ε is large, the temperature coefficient τf of the resonance frequency is close to 0, and the dielectric ceramic composition having a large Q value is obtained by adding and mixing a porcelain composition having a large τf to the positive side and a ceramic composition having a large negative side. The purpose is to get things.

[0009]

Means for Solving the Problems The present inventors have found that the composition formula is represented by (Li ¹⁺ _1/2 · R ³⁺ _1/2 ) · TiO ₃ , and R ³⁺ is L
In a dielectric porcelain composition containing one or more of a ³⁺ , Nd ³⁺ , Sm ³⁺ , Co ³⁺ and Pr ^3+, a specific amount of Bi ³⁺ is used as a part of R ^3+. It has been found that by containing, a larger dielectric constant ε can be obtained and the temperature coefficient τf of the resonance frequency can be suppressed from increasing as compared with the dielectric ceramic composition.

Further, the present inventors have made it possible to adjust τf by, for example, making the temperature coefficient τf of the porcelain composition close to zero by replacing a part of Li ^{1+ in} the above composition formula with Na ¹⁺ . Knowing that the present invention can be performed, the present invention has been completed.

According to the present invention, the composition formula is represented by {(1-u) Li
¹⁺ + uNa ¹⁺ ｝ _1/2・ ｛xBi ³⁺ （(1-x) R ³⁺ ｝ _1/2
R ³⁺ is represented by TiO ₂ , La ³⁺ , Nd ³⁺ , and Sm
^The dielectric ceramic composition for microwaves includes one or more of ³⁺ , and u and x satisfy the following values. 0.03 <u <0.8 0 <x <0.7

[0012]

BEST MODE ^FOR CARRYING OUT THE INVENTION According to the present invention, a composition formula (Li ¹⁺
_1/2・ R ³⁺ _1/2 ) ・ TiO ₃ , where R ³⁺ is La ³⁺ , N
A dielectric ceramic composition containing one or more of d ³⁺ , Sm ³⁺ , Co ³⁺ and Pr ³⁺ , characterized in that Bi ³⁺ is contained as a part of R ^3+. .

The Bi ³⁺ content has the effect of improving the dielectric constant ε, but when Bi ³⁺ exceeds 0.7, Bi ₂ O ₃ as Bi ³⁺ has a low melting point, so that the porcelain composition during firing has a low melting point. However, it is not preferable because it may react and fuse with the floor plate or the floor powder.

In the present invention, the reason why the substitution amount of Na ^{1+ which} partially replaces Li ¹⁺ is limited to 0.03 to 0.8 is that if it is less than 0.03, τf becomes a large negative value,
If it exceeds 0.8, τf becomes a large plus value, which is not preferable.

[0015]

EXAMPLE Composition formula {(1-u) Li ¹⁺ + uNa ¹⁺ } _1/2
｛XBi ³⁺ · (1-x) R ³⁺ ｝ _1/2 · TiO ₂
Li ¹⁺ and Na ¹⁺ with different mixing ratios and Bi ³⁺ with different mixing ratios
And R ³⁺ as La ³⁺ , Nd ³⁺ , Sm ³⁺ , Co ³⁺ , Pr ³⁺
La ₂ as a raw material so that a porcelain composition consisting of
_{O 3, Nd 2 O 3,} Sm 2 O 3, Co 2 O 3 and Pr ₆ O _{1 1} and _{Li 2 CO 3, Nd 2 O} , Bi 2 O 3, a predetermined molar fraction of high purity powder of TiO ₂ It was blended so that

Thereafter, the mixture is mixed for 5 to 20 hours by a ball mill, calcined at 700 ° C. to 1000 ° C. for 1 hour, and then pulverized again for 2 to 50 hours. After classification, the resultant was molded into a disk having a diameter of 10 mm and a thickness of 6 mm at a pressure of ^{2 to 3} T / cm ² . After sintering the molded body at 1200 ° C. to 1400 ° C. for 1 to 5 hours, both sides were polished so that the thickness of the sintered body was の of the diameter, to prepare a measurement sample.

The dielectric constant ε, the Q value, and the temperature coefficient τf of the resonance frequency of the measurement sample were measured at a measurement frequency of 3 GHz by the Hakki & Coleman method. Table 1 shows Li ¹⁺ and Na
The mixing ratio of ¹⁺ is different, and R ³⁺ is Bi ³⁺ , La ³⁺ , Nd
The dielectric constant ε, the Q value, and the temperature coefficient τf of the resonance frequency of the porcelain compositions having different mixing ratios of ³⁺ , Sm ³⁺ , Co ³⁺ , and Pr ³⁺ are shown.

[0018]

[Table 1]

[0019]

As described above, the dielectric porcelain composition according to the present invention
Formula (Li¹⁺ _1/2・ R³⁺ _1/2) ・ TiO _TwoIn, R³⁺
Specific amount of Bi as part of³⁺By containing
A larger dielectric constant ε was obtained than the dielectric ceramic composition.
And the temperature coefficient τf of the resonance frequency increases,
And Li¹⁺Part of Na¹⁺By replacing with
Adjust τf such as bringing the temperature coefficient τf of the vibration frequency close to 0
it can.

As apparent from the examples, the dielectric ceramic composition according to the present invention has a large dielectric constant ε, a temperature coefficient τf of the resonance frequency close to 0, a large Q value, and several GHz band. It is most suitable for resonators, filters, and dielectrics used in transceivers such as satellite communication broadcasting using microwaves or mobile object identification devices.

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[Procedure amendment]

[Submission date] January 22, 2001 (2001.1.2)
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

Means for Solving the Problems The present inventors have found that the composition formula is represented by (Li ¹⁺ _1/2 · R ³⁺ _1/2 ) · TiO ₃ , and R ³⁺ is L
a ^3+, Nd ^3+, the Sm ^{3 +} 1 type or a dielectric ceramic composition comprising two or more of, the specific amount as part of the R ³⁺ B
It has been found that by containing i ³⁺ , a larger dielectric constant ε can be obtained and the temperature coefficient τf of the resonance frequency can be suppressed from increasing as compared with the dielectric ceramic composition.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

[0012]

BEST MODE ^FOR CARRYING OUT THE INVENTION According to the present invention, the composition formula is (Li ¹⁺
_1/2・ R ³⁺ _1/2 ) ・ TiO ₃ , where R ³⁺ is La ³⁺ , N
d ^3+, in Sm ^{3 +} 1 type or a dielectric ceramic composition comprising two or more of, characterized in that it contains a Bi ³⁺ as part of the R ^3+.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

[0015]

EXAMPLE Composition formula {(1-u) Li ¹⁺ + uNa ¹⁺ } _1/2
｛XBi ³⁺ · (1-x) R ³⁺ ｝ _1/2 · TiO ₂
Li ¹⁺ and Na ¹⁺ with different mixing ratios and Bi ³⁺ with different mixing ratios
And La ³⁺ as _{^{R 3+, Nd 3+, La 2}} O 3 as a raw material as Sm ^{3 +} or Ranaru porcelain composition is obtained, Nd ₂ O _3, S
m ₂ O ₃ and _{Li 2 CO 3, N a 2} O, was formulated Bi ₂ O _3, so that a high purity powder of TiO ₂ becomes a predetermined mole fractions.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The dielectric constant ε, the Q value, and the temperature coefficient τf of the resonance frequency of the measurement sample were measured at a measurement frequency of 3 GHz by the Hakki & Coleman method. Table 1 shows Li ¹⁺ and Na
The mixing ratio of ¹⁺ is different, and R ³⁺ is Bi ³⁺ , La ³⁺ , Nd
^3+, the dielectric constant of the different ceramic composition of Sm ^{3 +} compounding ratio of epsilon, Q
The values and the temperature coefficient τf of the resonance frequency are shown.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Nishikawa 2- 15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Sumitomo Special Metals Co., Ltd. Yamazaki Works (72) Inventor Shigeru Kawahara 2 Egawa, Shimamoto-cho, Mishima-gun, Osaka Chome 15-17 Sumitomo Special Metals Co., Ltd. Yamazaki Works F-term (reference) 4G031 AA01 AA07 AA09 AA35 BA09 5E001 AB01 AE00 AE03 AE04 AH05 AH09 AJ02 5J006 HC07

Claims (1)

[Claims] 1. The composition formula is {(1-u) Li ¹⁺ + uNa.
¹⁺ ｝ _1/2 ｛xBi ^{3 +}・ (1-x) R ³⁺ ｝ _1/2・ TiO ₂
In expressed, R ³⁺ is La ^3+, Nd ^3+, and Sm ^{3 +} of 1
A dielectric ceramic composition for microwaves comprising at least one species and u and x satisfying the following values. 0.03 <u <0.8 0 <x <0.7