JPS6272558A - Dielectric ceramic composition - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The dielectric ceramic composition of the present invention can be used not only as a dielectric resonator material but also as a dielectric substrate for microwave ICs, for example.

It is also applied to dielectric adjustment rods, etc.

[Prior art and its problems]

In recent years, with the increasing integration of microwave circuits, there has been a demand for small, high-performance dielectric resonators.

The dielectric ceramic composition used in such a dielectric resonator has a large relative dielectric constant ε1.

Characteristics such as excellent stability of the temperature coefficient τf of the resonant frequency and linearity of the temperature characteristic of the resonant frequency, and the ability to construct a resonator with a large no-load Q are required. Conventionally, TlO2 and BaO-T are used as such dielectric ceramic compositions.
Those containing iO2 as a main component are common, but they have problems such as large loss in the microwave band where the temperature coefficient of dielectric constant is large.

As this improved system, for example, B a O-T i Oz −
N d 203 is B a O in the main publication No. 102003.
-T i O2-N d 203.

A dielectric resonator material has been proposed in which a trace amount of Bi2O3 is added as an additive to improve the no-load Q.
), which makes it difficult to put it into practical use.

On the other hand, recently v B a (M fy ・T a H)
O3 and Ba(ZnKTa2,4)03. Ba(Zn
34"bz, g) Os-based dielectric ceramics with a perovskite structure are known. However, these materials have a small dielectric constant (el-=25 to 40), so it is difficult to miniaturize the resonator sufficiently. There is a drawback that it cannot be done.

The object of the present invention is to provide dielectric resonator materials, in particular 0.1-4
An object of the present invention is to provide a dielectric ceramic composition suitable as a dielectric resonator material used in the GHz band.

Furthermore, the object of the present invention is to have a high dielectric constant and a large Q.

The object of the present invention is to provide a dielectric ceramic composition having good stability of τf and good linearity of temperature characteristics.

The purpose of the present invention is to:

Composition formula % formula % (wherein, X is 0.1-0, 2.y is 0.5-0.8.Z
is 0.1 to 0.2, x+y+z=1, and t is 0.
It is 1 to 0.2. ) is achieved by a dielectric ceramic composition consisting of barium, titanium, neodymium, bismuth and oxygen.

The present invention contains Bad, TiO2 and Nd2o3 as main components, and in particular contains a larger amount of BiO% than conventional porcelain compositions.
In other words, in the above compositional formula, X+7+Z is set to 1 mol, and B10y is added to this by 0.1 to 1 mole.
By containing 0.2 mol, the temperature coefficient of the resonance frequency can be made 10 ppm/'C or less, making it possible to achieve the above-mentioned object of the present invention.

The dielectric ceramic composition according to the present invention has a large dielectric constant, and also has a large no-load Q value when forming a resonator. Furthermore, it has a stable temperature characteristic of a resonant frequency, and particularly has good linearity in the temperature characteristic at -40°C to 60°C.

〔Example〕

Two embodiments of the present invention will be described in detail below.

The dielectric ceramic composition according to the present invention is made of barium.

It can be manufactured by a method in which starting materials such as carbonates and oxides of titanium, neodymium, bismuth, etc. are mixed and calcined, then shaped, fired, and sintered.

First, predetermined amounts of each of barium carbonate, titanium oxide, neodymium oxide, and bismuth oxide are wet-mixed with a solvent such as water and alcohol. Next, water.

After removing alcohol and the like, it is pulverized and calcined at 900 to 1100°C for about 5 hours in an oxygen-containing gas atmosphere (for example, air atmosphere). The calcined product thus formed is pulverized, then mixed with an organic binder such as polyvinyl alcohol to make it homogeneous, dried, pulverized, and pressure-molded (at a pressure of 100 to 1000 Kg/-). Then, this molded product is placed in an oxygen-containing gas atmosphere such as air at a temperature of 1,300 to 1
By firing at 450°C, the above dielectric ceramic composition can be obtained.

The dielectric ceramic composition thus obtained can be used as is or by processing it into an appropriate shape and size as necessary.
It can be used as a material for dielectric resonators, dielectric substrates for micro technology C, dielectric adjustment rods, etc.
Excellent effects can be achieved when used as a dielectric resonator used in the 4 GHz band.

[Example 1] 0.15 mol of barium carbonate (BaCO3) powder, 0.70 mol of titanium oxide powder (Ti02), 0.15 mol of neodymium oxide powder (Nd203) and 0.10 mol of bismuth oxide powder (Bi03A) were added to ethanol. The mixture was placed in a ball mill and mixed for 10 hours. The mixture was taken out from the ball mill, the solvent ethanol was evaporated, and the mixture was ground for 1 hour using a millstone. The pulverized product was calcined at 950°C in an air atmosphere, and then pulverized again using a leprosy crusher for 1 hour. After adding an appropriate amount of polyvinyl alcohol solution and mixing uniformly, this pulverized product has a diameter of 15 mJL and a thickness of 5.5 m.
Formed into 5m pellets and heated at 1360°C in an air atmosphere.
Bake for 2 hours.

The dielectric ceramic composition of this example (0,15Ba0
・0.70T102・0.15Nd203・0.10B
iO%) was obtained.

The thus obtained porcelain composition of Example 1 was prepared with a diameter of 9 g,
Thickness 31111! After cutting to the size of
The no-load Q and relative dielectric constant ε were determined. Also,
The temperature dependence of the resonance frequency was measured in the range of -40 to 50°C, and the temperature coefficient τf was determined. The results are shown in Table 1.

[Examples 2 to 5] Bismuth oxide powder (Bib, 4) of Example 1 0.10
mole, 0.12 mole (Example 2), o, 1 s mole (
Example 3), 0.17 mol (Example 4) and 0620
A dielectric ceramic composition was produced in the same manner as in Example 1, except that the molar ratio was changed to molar (Example 5), and the characteristics were measured in the same manner. The results are shown in Table 1.

[Comparative Examples 1 to 4] Bismuth oxide powder of Example 1 (Bi○3/2) 0.10
The mole was not added (Comparative Example 1), o, o1 mole was changed (Comparative Example 2), and o was changed to 0.02 mole (Comparative Example 3).
) and 0.25 mol (Comparative Example 4), a dielectric ceramic composition was produced in the same manner as in Example 1, and its properties were measured in the same manner. The results are shown in Table 1.

Table 1 *A=0.15BaO-0,70Ti02-0.15N
d203 [Effect of the invention] The dielectric ceramic composition of the present invention has a high dielectric constant and a large Q,
The stability of τf is good, the linearity of temperature characteristics is good,
It is suitable as a dielectric resonator material, especially as a resonator material used in the 0.1 to 40H2 band.

Claims (1)

[Claims] Compositional formula xBaO・yTiO_2・zNd_2O_3・tBiO
_3_/_2 (in the formula, x is 0.1 to 0.2, y is 0.5
~0.8, z is 0.1-0.2, x+y+z=1, and t is 0.1-0.2. ) A dielectric ceramic composition consisting of barium, titanium, neodymium, bismuth and oxygen.