JPH0616364B2 - Dielectric porcelain composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dielectric ceramic composition suitable as a dielectric resonator material.

More specifically, according to the present invention, when the dielectric resonator is used in the microwave frequency band (for example, 2 to 10 GHz band), the unloaded Q (Qu) is particularly large and the dielectric constant (εr) is appropriately large. ) And having excellent stability of the temperature coefficient (τf) of the resonance frequency, the present invention relates to a dielectric ceramic composition.

Dielectric resonator materials with low dielectric loss,
In other words, it is required that the value of the no-load Q is as large as possible and the temperature characteristics are stable, and the performance of the resonator greatly depends on these.

The size of the dielectric resonator is It is inversely proportional to, and the larger the relative permittivity, the smaller the resonator can be and the circuit can be miniaturized. Therefore, it is generally desirable that the relative permittivity be large as a resonator material, but if it is too large, the resonator becomes too small. Since it becomes too much and it is rather difficult to handle, an appropriately large dielectric constant is required.

[Prior Art] For a dielectric ceramic composition used as a dielectric resonator material, for example, Ba (Zn _1/3 Ta _2/3 ) O ₃ −Ba (Mg _1/3 Ta _2/3 )
O ₃ system, CaTiO ₃ −MgTiO ₃ −La ₂ O ₃ −2TiO ₂ system, Sr (Zn _1/3 Nb
_2/3 ) O ₃ -SrTiO ₃ system has already been proposed.

[Problems to be solved by the invention]

However, a dielectric ceramic composition proposed as a dielectric resonator material, for example, even if the relative dielectric constant has an appropriate size, the unloaded Q is small, the temperature coefficient of the resonance frequency is too large, and The relative dielectric constant is too large, and there are many disadvantages when actually used as a dielectric resonator in the microwave frequency band.

DISCLOSURE OF THE INVENTION The present invention provides a dielectric ceramic composition which can improve the above-mentioned problems as a dielectric resonator material conventionally used in a microwave frequency band, in particular.

The present invention also provides a dielectric ceramic composition suitable as a dielectric resonator material, which can satisfy all of no load Q, relative permittivity and temperature coefficient of resonance frequency when used as a dielectric resonator. It is something to do.

[Means for solving problems]

The present invention provides a general formula: Ba _x Sr _1-x [(Zn _y Me _1-y ) _1/3 Nb _2/3 ] 0 ₃ (wherein Ba barium, Sr is strontium, Zn is zinc,
Me is magnesium and / or nickel, Nb is niobium and 0 is oxygen, the subscript is the number of atoms, 0.2 <x
<0.5, 0.2 <y <0.9. ) Related to the dielectric magnetic composition.

In the dielectric porcelain composition of the present invention, magnesium and nickel exhibit excellent electrical characteristics as in the later-described examples even if both of them are contained or only one of them is contained.

However, if the composition of the dielectric ceramic composition is out of the range represented by the above general formula, for example, the dielectric loss becomes large and the temperature characteristics become poor, which is not preferable.

The dielectric porcelain composition of the present invention is prepared by using carbonates, oxides, etc. of barium, strontium, zinc, magnesium, nickel, etc. as starting materials, mixing and calcining them, and then molding and firing them to sinter them. Can be manufactured in.

For example, barium carbonate, strontium carbonate, zinc oxide, niobium pentoxide, magnesium oxide, and / or nickel oxide are wet-mixed with a solvent such as water or alcohol, and then water or alcohol is removed and pulverized to obtain oxygen. 80 in a contained gas atmosphere, for example, in an air atmosphere
After calcination for about 10 hours at 0 to 1400 ° C., crushing the calcined product, adding an organic binder such as polyvinyl alcohol, drying and crushing, pressure molding (pressure 100 to 100)
0 kg / cm ² ) and firing the molded product at 1400 to 1650 ° C. in an oxygen-containing gas atmosphere such as air to obtain a dielectric ceramic composition. This dielectric porcelain composition may be used as it is, or may have an appropriate shape and size according to the purpose, for example, a diameter of 5 to 30 mmφ and a thickness of 2 to 12
It can be used as a high-performance dielectric resonator by processing a disk shape of about mm. The dielectric ceramic composition can be used not only as a dielectric resonator material, but also as a material for a microwave IC dielectric substrate, a dielectric adjusting rod, and the like.

〔Example〕

Example 1 0.27 mol of barium carbonate [BaCO ₃ ] powder, 0.43 mol of strontium carbonate [SrCO ₃ ] powder, zinc oxide [ZnO]
Powder 0.18 mol, niobium pentoxide [Nb ₂ O ₅ ] powder 0.2
3 mol and 0.05 mol of magnesium oxide [MgO] powder were put into a ball mill together with ethanol and wet-mixed for 10 hours, and then the mixture was taken out from the ball mill to evaporate the ethanol in the melt and crushed and ground for 1 hour with a crusher. did.

The crushed product was calcined in an air atmosphere at 1200 ° C. for 10 hours and then crushed and crushed again by a crusher for 1 hour.

Polyvinyl alcohol solution was added to the obtained calcined powder to make it uniform, then dried and pressure-molded into pellets with a diameter of 15 mmφ and a thickness of 7 mm, which were fired and sintered at 1530 ° C. for 4 hours in an air atmosphere and sintered. A dielectric ceramic composition was obtained.

The dielectric ceramic composition, which diameter 11Mmfai, after cutting to a size of a thickness of 5 mm, as measured by a dielectric resonator method, the no-load at the resonant frequency (f ₀₎ (Q _U) and the relative dielectric constant ( ε _r ) was determined. Regarding the temperature dependence of the resonance frequency, the temperature coefficient (τ _f ) was obtained by measuring in the range of −40 ° C. to + 50 ° C. The results are shown in Table 1.

Examples 2 to 9 Dielectric ceramic compositions were produced in the same manner as in Example 1 except that the amount of the starting materials used was changed so that the dielectric ceramic composition had the composition shown in Table 1. The electrical characteristics were measured in the same manner as in. The results are shown in Table 1.

Examples 10 to 18 Using the nickel oxide [NiO] in place of the starting magnesium oxide of Example 1, the dielectric ceramic compositions shown in Table 1 were produced in the same manner as in Example 1, and The electrical characteristics were measured in the same manner as in 1. The results are shown in Table 1.

EFFECTS OF THE INVENTION The dielectric ceramic composition of the present invention has not only a large unloaded Q value but also a moderately large relative permittivity and stable temperature characteristics. It is suitable as a container material, and using this as a resonator has the advantage that the performance of the receiver can be greatly improved and the size can be reduced.

Claims (1)

[Claims] 1. A general formula, Ba _x Sr _1-x [(Zn _y Me _1-y ) _1/3 Nb _2/3 ] 0 ₃ (wherein Ba is barium, Sr is strontium, Zn is zinc, and Me is Is magnesium and / or nickel, Nb is niobium and 0 is oxygen, the subscript is the number of atoms, 0.2
<X <0.5 and 0.2 <y <0.9. ) Dielectric magnetic composition represented by.