JPS6340213A - Dielectric ceramic composition for microwave - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dielectric ceramic composition for microwave use, and in particular to a microwave filter, an LNB ○SC (oscillator), a duplexer, and a VCO (voltage controlled oscillator). The present invention relates to a composition suitable for dielectric ceramic materials for microwave circuits such as the above.

[Conventional technology]

Dielectric materials have been widely applied to microwave circuits such as oscillators for receiving 4rJ star broadcasts.

In recent years, this trend has been accelerated more and more, and the frequency band has expanded to the low frequency range, the sub-millimeter wave range, and the millimeter wave range, and higher performance dielectric materials are required. Conventionally, Ba0-TtOz-based dielectric materials have been used as dielectric materials for use in boats.

[Problem that the invention seeks to solve]

In BaO~TiOz-based dielectric materials, BaO
and T i O*, or BaO
It is possible to freely control the temperature coefficient of the dielectric material by using appropriate additives for the composition of the dielectric material.However, the conventional Ba0TiO□-based dielectric material as mentioned above is The sintered body is easily reduced, resulting in large dielectric loss and problems such as insufficient linearity of temperature characteristics.

An object of the present invention is to solve the problems of the conventional fJi described above, and to provide a microstructure that has a high dielectric constant, a small dielectric loss, and a small temperature coefficient of the dielectric constant, and the temperature coefficient is constant within a predetermined temperature range. An object of the present invention is to provide a dielectric ceramic composition for waves.

[Means for solving problems]

For the above purpose, Ba0 (18-22 mol%), Ti0z (78-8
2 mol%), Nb, 03
(0.5-3.5% by weight) and Z r Ot (0.1-3
．． N b t○,
(0.5-3.5% by weight) and Z r Oz (0.1-3
．． This is achieved by using a dielectric ceramic composition containing ZnO (0% by weight or less) and ZnO (17% by weight or less).

In the microwave dielectric ceramic composition of the present invention, Ba
The main components are d (18 to 22 mol 9A) and Ti0t (78 to 82 mol %). When BaO and TiOz are outside the above range, the dielectric loss increases in both cases,
It becomes impossible to measure the properties of the dielectric material.

The present invention has the above-mentioned components as main components, and Nbt.
It has a composition in which O, and Zr01 are added. The amount of NbzOs added is 0.5-3.5% by weight. N
The addition of b z Os increases the temperature coefficient of the dielectric material by +70
The purpose is to maintain the temperature constant within the range of ℃ to -50℃, but if the amount added is less than 0.5% by weight, the effect will be small, while if the amount added exceeds 3.5% by weight, the temperature coefficient will be It becomes difficult to keep it constant, and the no-load Q (Qu) further decreases. The amount of ZrO added is 0.1 to 3.0% by weight. The purpose of adding ZrO is to reduce the dielectric loss of the dielectric material, and if the amount added is less than 0.1% by weight, the effect of reducing dielectric loss will be low;
On the contrary, if it exceeds 0% by weight, the dielectric loss increases.

In the present invention, in the case of a dielectric ceramic composition containing ZnO, ZnO can change the temperature coefficient (τf6) of the dielectric material from positive to negative while maintaining the dielectric constant (εr) at 30 or more. can. In this case, if the amount of ZnO added exceeds 17% by weight, the temperature coefficient (τ, .) becomes too large on the negative side and the dielectric constant (ε'') further decreases.

[Embodiments of the invention]

Raw materials BaC0=, Ti0z, ZnO, NbtO3, and ZrOZ were weighed so as to have the respective compositions shown in Table 1, and after wet In association, they were overdried and calcined at a temperature of 1000°C. After crushing, granulating and molding this calcined product, 1
Samples fired in the air at temperatures of 200-1350°C for 10 hours were measured at a frequency of about 13GH. The results are shown in Table 1.

Although BaCO was used instead of BaO as a raw material, carbonates such as 3aCO* are chemically more stable than oxides such as BaO, and in the calcination process, B
a Since COi is decomposed into BaO and COz, it does not affect the properties of the dielectric material.

Further, FIG. 1 shows the relationship between the amount of Nb2O5 added and the temperature characteristics of the dielectric material in Examples 4, 11, and 12 shown in Table 1.

From Table 1, Examples 1 to 14 all have a dielectric constant (ε
While keeping r) high, the no-load Q (Qu) is set to 300.
0 or more, and the temperature coefficient is r. This shows that you can freely control it.

Also, from Figure 1, when the amount of Nbz○ added is 2.5% by weight, the temperature/frequency change can be made most linear, and NbzO
When the amount of NbtOs added is 0.5% by weight, the effect of making the temperature/frequency change linear is slightly lower than when it is 2.5% by weight, and furthermore, when the amount of NbtOs added is 3.5% by weight, the temperature/frequency change becomes linear. /
The linearity of the frequency change increases considerably and therefore Nbt
It is recognized that when the amount of Os added exceeds 3.5% by weight, the temperature characteristics deteriorate.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to sufficiently ensure linearity of temperature characteristics while maintaining a high dielectric constant (and a low dielectric loss).

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the amount of Nb, o, added and the temperature characteristics of the dielectric material.

Claims (2)

[Claims] (1) BaO (18-22 mol%), TiO_2 (78
~82 mol%), Nb_
2O_3 (0.5-3.5% by weight) and ZrO_2 (0.5% to 3.5% by weight).
1 to 3.0% by weight) of a dielectric ceramic composition for microwave use. (2) BaO (18-22 mol%), TiO_2 (78
~82 mol%), Nb_
2O_3 (0.5-3.5% by weight) and ZrO_2 (0.5% to 3.5% by weight).
1 to 3.0% by weight) and ZnO (17% by weight or less).