JPS59191204A - 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 (BaO), titanium oxide (TiO
2), samarium oxide (Sm2o3) and iron oxide (F
The present invention relates to a high frequency dielectric ceramic composition composed of the following components: e203).

Conventional configuration and its problems In recent years, the technology of high-frequency circuits that handle microwaves and MIJ waves (hereinafter collectively referred to as microwaves) with wavelengths of several degrees or less has progressed.・Proactive efforts are being made to shape the system.

Until now, cavity resonators, antennas, etc. have been used in these high-frequency circuits, but their size is comparable to the wavelength of microwaves, which has been an obstacle to miniaturization. In order to solve this problem, methods have been taken to shorten the wavelength itself by using dielectric ceramics with a high dielectric constant. T102-based materials are often used as materials suitable for such uses; for example, T102
-Z T02-3n○2 series, Ca TiOs -Mg
Dielectric ceramics such as T 103- L a 203-2 T z○2 series and recently Ba (Zn%Nb%)Q3 series are known. However, when a dielectric resonator is made of these materials, the dielectric constant is as low as 30, so for example, in an X-band dielectric resonator with a resonance frequency of about 11 GHz, 1 is a material with εr-30. When using the same material with ε1 = 30, it becomes a small unit with a diameter of 5.6mm and a thickness of 2.2mm, but when the frequency is lowered to about 2GHz and is used in the UHF band, the same material with ε1 = 30 has a diameter of 30mm. -7
The shape of the joint is significantly large, with a thickness of 12 mm and approximately 3 mm. If the dielectric constant of the material used here can be increased to about 80, the size will be 18.8wn in diameter,
Although it can be made smaller with a thickness of 7.7 mm, conventional materials have not been able to satisfy such requirements.

Purpose of the Invention The present invention has been made to improve the above-mentioned drawbacks, and has a large relative dielectric constant ε and no-load θ, and a stable temperature coefficient τf of the resonance wavenumber. The present invention aims to provide a dielectric ceramic whose temperature coefficient can be varied over a wide range.

Structure of the Invention The present invention is a material that satisfies the above-mentioned needs, and is made of xBao-
In the composition represented by yTio2-zStn203, 6≦X≦23 (molti), 57≦y≦82.5 (mol%
), 2.5≦2≦37.5 (Morch), x 10 y + z = 1
Fe2O3 for the main components in the range of 00 (mol%)
This porcelain has a composition in which 3% by weight or less (excluding 0% by weight) of 0% by weight or less is added, and is excellent as a dielectric porcelain for high frequency use.

Description of Examples The starting material is chemically highly purified Ba(:X:)3t.
T i○2, Sm2o3, and Fe2Q3 were weighed to have a predetermined composition, and wet mixed with pure water in a rubber-lined ball mill equipped with an agate ball. This mixture was taken out 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 the crushed slurry was dehydrated and dried, 8 parts by weight of a polyvinyl alcohol solution with a concentration of 3 parts was added to the powder as a binder to make it homogeneous, and then the powder was sized by passing through a 32≠mesh sieve. The sized powder was molded into a disk with a diameter of 20 m and a thickness of about 8 mm using a mold and a hydraulic press at a molding pressure of 800 kg/ca. The molded body is placed in a pot made of high-purity alumina and heated to a temperature of 122o to 1550o in air depending on the composition.
The mixture was held at a temperature within the range of .degree. C. for 2 hours and fired to obtain dielectric porcelain having the composition shown in the table. Using this ceramic element, the resonant frequency, no-load θ, and relative permittivity were determined from measurements using the dielectric resonator method. The temperature dependence of the resonant frequency was measured in the range of -30"C to 7Q"C, and the temperature coefficient τ
I found f. The resonant frequency was 2-4 GHz. The experimental results 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 θ while maintaining a high relative dielectric constant. In addition, 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 can be used 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) exceeds 23 momoles or the amount of TiO3 (
y) decreases by 57 momoles or Sm2o3
If the amount (z) is less than 2.5 moles,
This is excluded from the scope of the present invention because it becomes difficult to sinter the porcelain and the no-load θ decreases, making it impossible to measure. In addition, if X becomes less than 5 molar coefficient or 2 becomes more than 37.5 molar coefficient, the sintering of the porcelain becomes unstable and the no-load θ decreases, making it impossible to measure. ,
If y increases by more than 82.5 moles, the sintering of the porcelain becomes unstable and changes in temperature characteristics become significantly large, so it is excluded from the scope of the present invention.

In addition, regarding the amount of Fe2o3 added as a subcomponent, as the amount added increases, it is possible to lower the sintering temperature of porcelain and increase the no-load θ, as well as change the temperature characteristics. , 3 weight coefficient, the dielectric constant and the no-load θ drop significantly, and this is excluded from the scope of the present invention.

Effects of the Invention The dielectric ceramic composition of the present invention has a large dielectric constant in the microwave frequency band, a large no-load θ, and a stable temperature coefficient of the resonant frequency, which reduces the temperature dependence of oscillators and resonators. Useful for stabilizing In addition, since it has a high dielectric constant, it is suitable for use in the UHF band, and small, high-performance electronic circuit components can be made. moreover,
Since a desired τf can be selected by changing the composition of the filler material, when the dielectric resonator is assembled, it is possible to provide a temperature compensation effect that eliminates the influence of the surrounding metal plates on the temperature characteristics.

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 great industrial utility value. It is.

Claims (1)

[Claims] Dielectric porcelain consisting of barium oxide, titanium oxide, samarium oxide, and iron oxide, whose main component composition formula is xBa○-y.
When expressed as TIO2-2Sm203, z, y. Z is 5≦X≦23 (mol%), 57≦y≦82.5 (mol%), 2.6≦2≦37.5 (mole ratio), x + y
+z = 100 (mol %), and a dielectric ceramic composition characterized in that Fe203 is added in an amount of 3 weight or less (excluding 0 weight %) based on the main component.