JPS603801A - Dielectric porcelain 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 Field of Industrial Application The present invention is applicable to barium oxide (Bad), titanium oxide (T i
02) The present invention relates to a high frequency dielectric ceramic composition composed of samarium oxide (Sm2o3) and zirconium oxide (ZrO2).

Conventional configurations and their problems In recent years, with the advancement of high-frequency circuit technology that handles microwaves and millimeter waves (hereinafter collectively referred to as microwaves) with wavelengths of several centimeters or less, it has become difficult to miniaturize this circuit. It is being actively pursued. Until now, cavity resonators, antennas, and the like have been used in these high-frequency circuits, but the size of these devices is comparable to the wavelength of microwaves, which poses an obstacle to miniaturization. To solve this problem, a method has been used to shorten the wavelength itself by using dielectric ceramics with a high dielectric constant.

TiO2-based materials are often used as materials suitable for such uses, such as Tio2-Zro2-8.
n O2 system, CaTi○s M g T iO3L a
2032, T zo2 series, and recently B a (Zn
Dielectric ceramics such as %TaH)o3-Ba (Zn%Nb%)o3 system are known.

However, when a dielectric resonator is made of these materials, the dielectric constant is as low as about 30. For example, in an X-band dielectric resonator with a resonance frequency of about 11'GHz, εr-
When using material No. 30, the diameter is 6.6 mm and the thickness is 2.
．． Although it is a small unit of about 2 mm, if the frequency is lowered and used in the UHF band of about 2 GHz, the same ε,
= 30, the diameter is 30.7 mm and the thickness is 12.
The shape is significantly larger, about the size of three temples. If the dielectric constant of the material used here could be increased to about 80, the size could be reduced to about 18.8 mm in diameter and 7.5 mm thick, but conventional materials meet these requirements. could not be satisfied.

Purpose of the Invention The present invention has been made in order to improve the above-mentioned drawbacks.The present invention has been made to improve the relative dielectric constant and no-load Q, and to have a stable temperature coefficient of the resonant frequency. The purpose of this invention is to provide a dielectric ceramic that can be varied over a wide range.

Components of the Invention The inventors have conducted various studies on materials that meet the above requirements, and found that in the composition represented by xBao-yTio-zsm203, 5≦X≦23 (mol %).

57≦y≦82.5 (mol%), 2.5≦2≦37
．． 6 (mol%), x + y - 1 - z = 100 (mol%) of the main component, and the porcelain has a composition in which 5 weight or less of SnO2 is added and contained, which is an excellent high frequency dielectric porcelain. That's the headline.

Description of Examples Starting materials include chemically highly purified B a Co a +
T 102.

Sm2O3 and ZrO2 were wet mixed with pure water to a predetermined composition in a rubber-lined 90-ball mill equipped with a weighed agate ball. This mixture was removed from the ball mill, dried, and then calcined in air at a temperature of 900° C. for 2 hours. The calcined product was wet-milled together with pure water in the ball mill described above. After dehydrating and drying the crushed slurry, the powder was sized through a Barash sieve. The sized powder was molded into a disk with a diameter of 20 mm and a thickness of about 8 cylinders at a molding pressure of 800 V using a mold and a hydraulic press. The molded body is #fJ[tD 7tv, if @ ('#(7)9A
ft, 1m1RKi U.

The mixture was then fired in air at a temperature within the range of 1,220 to 1,560° C. for 2 hours to obtain dielectric porcelain having the composition shown in the table. Using this ceramic element, the resonant frequency, no-load Q, and dielectric constant were determined by measurements using the dielectric resonator method. The temperature dependence of the resonance frequency was measured in the range of -30°C to 70°C, and the temperature coefficient τf was determined. The resonant frequency was 2-4 GHz.

The experimental results obtained are shown in the table. Note that the samples marked with ■ in the table are comparative examples outside the scope of the present invention, and the other samples are examples within the scope of the present invention.

(The following is a blank space) As is clear from the table, the dielectric ceramic within the scope of the present invention can increase the no-load Q while maintaining a high relative dielectric constant. However, since the dielectric ceramic of the present invention exhibits stable temperature characteristics of the resonant frequency, it is useful for stabilizing the temperature dependence of oscillators and resonators, and furthermore, because of its large dielectric constant, it is suitable for use in the UHF band. It can be used to create small, high-performance electronic circuit components.

To explain the reason for limiting the range of the main component composition, BaO
The amount (x) is 23 momoles more or T 10
2 amount (y) is less than 57 momoles or Sm
If the amount of 2O3 (z) is less than 2.6 molar ratio, it becomes difficult to sinter the porcelain, and the no-load Q decreases, making it impossible to measure, and is therefore excluded from the scope of the present invention. However, if X is less than 5 moles or 2 is more than 37.6 moles, the sintering of the porcelain becomes unstable and the no-load Q decreases, making it impossible to measure.
．． If the amount is more than 5 mol or more, the sintering of the porcelain becomes unstable and the temperature characteristics change significantly, so it is excluded from the scope of the present invention.

In addition, regarding the amount of Z r O2 added as a subcomponent, if the sintering temperature of porcelain can be lowered as the amount added increases, the no-load Q can be increased, and the temperature characteristics can also be changed. However, if more than 6% by weight is added, the relative permittivity and no load will increase.

This is excluded from the scope of the present invention because the decrease in

Effects of the Invention The dielectric ceramic composition of the present invention has a large dielectric constant in the microwave frequency band and is unloaded. is large, and the temperature coefficient of the resonance frequency exhibits a stable value, so it is useful for stabilizing the temperature dependence of oscillators and resonators. Also,
Due to its large dielectric constant, it is suitable for use in the UHF band.
High-performance electronic circuit components can be made using the JS type. Furthermore, the temperature coefficient of the desired resonance frequency can be selected by changing the composition of the material, so when the dielectric resonator is assembled, a temperature compensation effect that eliminates the influence of the surrounding metal plates on the temperature characteristics can be achieved. It can be made to stand. In addition, the dielectric ceramic composition of the present invention can provide a material useful not only for dielectric resonators but also for microwave substrates, dielectric adjustment rods, etc., and has industrial utility value. It's big.

Claims (1)

[Claims] Dielectric porcelain consisting of barium oxide, titanium oxide, samarium oxide, and tin oxide, whose main component composition formula is x B a
When expressed as Oy T iO22S l111203, x, y, z are 5≦X≦23 (mol%), 67≦y≦
82.5 (mol%), 2.5≦Z≦37.6 (mol%)
. A dielectric ceramic composition characterized in that Z r O2 is added in an amount of 6 weight φ or less based on the main component in the range of x 10 y 10 z = 100 (mol %).