JPH01234358A - Dielectric ceramic composition - Google Patents

Abstract

PURPOSE:To obtain the title ceramic composition having a small loss and a high dielectric constant and wherein the temp. characteristic of the resonance frequency can be widely changed by incorporating Sm2O3 into a specified composition of TiO2, BaO, and Nd2O3. CONSTITUTION:From 1 to 15wt.% Sm2O3 is incorporated into the composition consisting essentially of TiO2, BaO, and Nd2O3 and having a composition shown by the formula, wherein the component rates (x), (y), and (z) are limited to conform to 0.05<=x<=0.15, 0.50<=y<=0.75, 0.20<=z<=0.35, and (x+y+z)=1, to obtain the ceramic composition. The temp. characteristic of the resonance frequency of the ceramic composition can be changed in the range 0-100ppm/ deg.C by the amt. of Sm2O3 to be added in the frequency region of the microwave. Accordingly, the resonance frequency temp. of the resonator and a dielectric resonator can be easily stabilized when the ceramic composition is used, and a small-sized high-performance microwave circuit can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a dielectric ceramic composition used for oscillators, dielectric resonators, etc.

BACKGROUND ART Dielectric ceramic compositions have been applied to oscillators, dielectric resonators, etc. in the microwave frequency range.

In recent years, especially as the integration technology of microwave circuits has progressed, active efforts have been made to use dielectric ceramics with high permittivity and low loss and to miniaturize them in order to stabilize the frequency of oscillators. There is. Conventionally, these dielectric materials include BaO.TiOz ceramics and dielectric ceramic compositions in which a part of the BaO.TiOz ceramics is replaced with other elements.

Problems to be Solved by the Invention However, these materials have low dielectric constants, large dielectric losses, or are unable to obtain the desired resonant frequency temperature coefficient when configuring a dielectric resonator. There are many problems above.

Means for Solving the Problems In order to solve the above problems, the dielectric ceramic composition of the present invention has a composition represented by the general formula xBaO・yTi02L(z/2)NdzGa, where 0.05≦x ≦0.15, 0.5
0≦y≦0.75.0.20≦z≦0.35. X+y+
SmzOs is 1 to 1 for a composition in the range of 2=1.
It is added and contained within a range of 15% by weight.

Effect By adding and containing 5rnxOa, the temperature coefficient of co-photography frequency changes over a wide range from 0 to 1100 pp/°C.

Example An embodiment of the present invention will be described below.

First, as a starting material, BaTi0a or BaCO
3, TiOz, Nd2O3 and SmzOs powders were weighed to give a predetermined composition and wet mixed. After drying this mixture, it was made into a powder, to which a 10% polyvinyl alcohol solution was added as a binder, kneaded, and then passed through a sieve to size the powder. The sized powder is molded into a cylindrical shape and heated to 1200-1400℃ in air.
After firing at a temperature within the range of 2 to 10 hours, the resulting dielectric ceramic was used as a dielectric resonator, and the resonant frequency and no-load Q were measured.

The dielectric constant was calculated from the resonance frequency and the size of the dielectric ceramic. And the resonance frequency temperature characteristics = 25℃~50
Measured in the range of °C. In addition, the resonant frequency is 3~5GHz
Met. The experimental results are shown in Table 1 on the next page.

, 8□yoi! As a result of this experiment, the additive amount is 5l120! When the added content of I is 1 to 15% by weight, the amount of BaO (x), the amount of TE01 (y
), the amount of Nd2O3 (z) is x>0.15. Alternatively, if y<Q, 5'O, or z<0.20 (mole fraction), the no-load Q decreases and the resonant frequency temperature characteristic becomes large. Also, x<0.05. Or y>0.75.
Alternatively, if z>0.35, the no-load Q will decrease, making it unsuitable as a dielectric ceramic composition. Also, 5112
It was found that when the additive content of 0!5 exceeds 15% by weight, the dielectric constant decreases, and when it falls below 1% by weight, the resonance frequency temperature characteristics become large, making it unsuitable for use as a dielectric resonator composition. .

All compositions within the scope of the present invention have low loss, high dielectric constant, and resonance frequency temperature characteristics of 0 to 1100 pp/
It has been found that 'C can be varied over a wide range.

As described in the detailed description of the invention, the dielectric ceramic composition of the present invention has an additive of 5+1120 in the microwave frequency range.
Depending on the amount of 3, the resonance frequency temperature characteristics can be changed in the range of 0 to 1100 pp/°C. Therefore, by using the dielectric ceramic composition within the scope of the present invention, the resonant frequency temperature characteristics of a resonator or dielectric resonator can be easily stabilized, and a small and high-performance microwave circuit ( I can do that.

As described above, the dielectric ceramic composition of the present invention has high industrial utility value.

Claims (1)

[Claims] The main components are TiO_2, BaO, and Nd_2O_3, and its compositional formula is xBaO・yTiO_2・(z/2)Nd_
The component ratios x, y, and z when expressed as 2O_3 are each 0.05
≦x≦0.15, 0.50≦y≦0.75, 0.20≦
A dielectric ceramic composition characterized in that Sm_2O_3 is added in an amount of 1 to 15% by weight to a composition in which z≦0.35 and x+y+z=1.