KR0162873B1 - Dielectric ceramic composition for high frequency - Google Patents

Abstract

In order to obtain a further improved quality factor (Q), dielectric constant (K) and temperature coefficient (τ _f ) of the resonant frequency, 90 to 99 mol% of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4) in a dielectric ceramic composition of 0.5 to 5.0 mol% magnesium oxide and 0.5 to 5.0 mol% tantalum oxide or 0.5 to A 5.0 mol% composite of niobium oxide is added and in addition 0.75 to 1.5 wt% zinc oxide is added to provide a sintered dielectric ceramic composition for high frequency.

Description

High Frequency Dielectric Magnetic Composition

The present invention relates to a dielectric ceramic composition for high frequency, and more particularly, to a dielectric ceramic composition for high frequency which is a material of a dielectric resonator used for filters and vibrators of RF and microwaves.

As the use of high frequency communication systems such as mobile communication and satellite broadcasting is actively progressing, components operating in the frequency band 300 MHz to 300 GHz, such as resonator elements, band pass (or stop) filters, and microwave integrated circuits (MIC)

The importance of high-temperature dielectric ceramics is increasing.

High frequency dielectrics used in microwave communication systems,

1) Since the wavelength of microwaves in the dielectric is inversely proportional to the half power of the dielectric constant, the dielectric constant (K) must be large for the miniaturization of components.

2) Dielectric loss increases in proportion to frequency, so for high performance, quality factor Q, which is the inverse of dielectric loss tanδ, must be high.

3) The temperature coefficient (τ _f ) of the resonant frequency of the dielectric resonator is small and should have characteristics close to 0 ppm / ℃,

Incidentally, it is required that the change over time is small, the thermal conductivity is high, and the mechanical strength is high.

The dielectric ceramic composition for high frequency has been generally provided with the following.

Japanese Patent Laid-Open No. 3-75268 describes xTiO ₂ -yZrO ₂ -zSnO ₂ (0.3≤x≤0.6, 0.25≤y≤0.6, 0.025≤z≤0.2) as a main component, and 5% or less of Co and Nb in weight ratio. Disclosing the dielectric ceramic composition prepared by addition, it has a dielectric property with a quality factor (Q) of 9,300 and a dielectric constant (K) of 39.4, but the temperature coefficients of the measurement frequency band and the resonance frequency are not described.

Japanese Patent Application Laid-Open No. 4-106807 discloses MnO, Al ₂ O ₃ , CuO, Li in xTiO ₂ -yZrO ₂ -zSnO ₂ (0.3≤x≤0.6, 0.25≤y≤0.6, 0.025≤z≤0.2) as main components. the ₂ O ratio by weight is added to less than 5%, Nb ₂ O and discloses a dielectric ceramic composition having a composition 10% or less to ₅ ratio by weight, the quality factor is 8500 and the dielectric constant is 37.0 and the temperature coefficient of resonant frequency 10ppm / ℃ It has a dielectric characteristic of. However, since the actual usable temperature coefficient should be in the range of ± 5ppm / ℃ has a disadvantage that the temperature coefficient is too high.

Japanese Laid-Open Patent Publication No. 5-117024 discloses a dielectric ceramic composition containing (Zr, Sn) TiO ₄ as a main component and adding CaO content at 300 ppm or less. The dielectric properties of the dielectric ceramic composition is the quality factor of 15,000 and a dielectric constant of 37.0 at 3GHz, temperature coefficient of resonance frequency, but that _{-2ppm / ℃, TiO 2 -ZrO 2} -SnO ₂ based applications in a range of frequencies of the dielectric 7GHz Therefore, it is expected to show much lower value in this frequency band.

The commercially available dielectric material of Murata, Japan, has a Qf of 44,380 and a dielectric constant of 37.55 at 7 GHz.

Accordingly, an object of the present invention is to obtain a further improved quality factor (Q), dielectric constant (K) and temperature coefficient (τ _f ) of the resonant frequency required for increasing the use frequency in dielectric ceramic compositions for high frequency. In order to achieve the above object, the present invention replaces the existing pentavalent addition oxides Ta ₂ O ₅ and Nb ₂ O ₅ in the ZrO ₂ -SnO ₂ -TiO ₂ -based dielectric ceramic composition, and the addition oxides Ta ₂ O ₅ Alternatively, a novel high frequency dielectric ceramic composition is obtained in which divalent oxide Mgo is added together with Nb ₂ O ₅ .

Therefore, the present invention is 90 to 99 mol% (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6≤x≤1.0, 0≤y≤0.4, 0.6≤z≤1.4), 0.5 at A dielectric ceramic composition for high frequency, comprising 5.0 mol% magnesium oxide, 0.5 to 5.0 mol% tantalum oxide, and 0.75 to 1.5 wt% zinc oxide.

98.5 to 98 mol% of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6≤x≤1.0, 0≤y≤0.4, 0.6≤z≤1.4) as the main components in the composition range. The dielectric ceramic composition prepared by adding a composite of 1.0 to 1.5 mol% magnesium oxide and 1.0 to 1.5 mol% tantalum oxide, and additionally adding 0.75 to 1.5 wt% zinc oxide to the dielectric ceramic composition is particularly excellent. Do.

Further, in the compound of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4), x = 0.8, y = 0.2 And for (Zr _0.8 Sn _0.2 ) TiO _{4 with} z = 1.0, most preferred results are obtained.

In addition, the present invention is 90 to 99 mol% (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6≤x≤1.0, 0≤y≤0.4, 0.6≤z≤1.4), 0.5 At 5.0 mol% magnesium oxide, 0.5 to 5.0 mol% niobium oxide, and 0.75 to 1.5 weight% zinc oxide.

98.5 to 98 mol% of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6≤x≤1.0, 0≤y≤0.4, 0.6≤z≤1.4) as the main components in the composition range. The dielectric ceramic composition prepared by adding a composite of 0.75 to 1.25 mol% magnesium oxide and 0.75 to 1.25 mol% niobium oxide to 0.75 to 1.5 wt% zinc oxide was added to the dielectric ceramic composition. Especially excellent.

Further, in the compound (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4), x = 0.8, y = 0.2 and The most desirable result is obtained for (Zr _0.8 Sn _0.2 ) TiO _{4 with} z = 1.0.

The sample was prepared by a conventional method for preparing a dielectric ceramic composition, which will be briefly described as follows.

After each sample of high purity is weighed in a desired ratio, it is mixed with a ball mill, using an organic solvent as a dispersion medium. The mixed slurry is dried and then calcined. Then, using an organic solvent as a dispersion medium, the mixture is pulverized and mixed with an attrition mill, dried, pressed into a mold, and subjected to isostatic molding. The molded specimen is then fired in an atmospheric atmosphere.

The results of the embodiments described below are inferred from those of the high frequency dielectric ceramic composition according to the present invention in which a divalent oxide and a pentavalent oxide are added to the ZrO ₂ —SnO ₂ —TiO ₂ based dielectric ceramic composition in comparison with the conventional dielectric ceramic composition. It can be seen that the characteristic has an improved value. Specifically, at 7 GHz, the Qf is greater than 44,830 and reaches 52,808 (multiplying the value of 7 in the attached table by the value at 7 GHz), The constant reaches 38.48 and the temperature coefficient of the resonance frequency is -10ppm / ℃ ~ 10ppm / ℃ it can be seen that the very excellent dielectric properties.

In the following examples the invention will be explained in more detail. However, the present invention is not limited to the examples described below.

EXAMPLE

Example 1

(Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4) with a purity of at least 99.9%, and magnesium oxide, tantalum oxide and After zinc oxide was weighed in a ratio according to Table 1, the mixture was mixed with a ball of nylon and a zirconia ball for 24 hours. Ethyl alcohol was used as a dispersion medium, and the mixed slurry was dried and then calcined at 1150 ° C. for 5 hours. Ethyl alcohol was again used as a dispersion medium, pulverized and mixed for 2 hours using an Attrition Mill, dried, pressed into a mold having a diameter of 12.0 mm, and then subjected to isostatic molding. Thereafter, the molded specimen was fired in an atmosphere of air at a temperature of 1300 to 1450 ° C.

Its sintering temperature, dielectric constant and quality factor are also shown in Table 1.

Example 2

(Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6≤x≤1.0, 0≤y≤0.4, 0.6≤z≤1.4) with purity of 99.9% or more, magnesium oxide, niobium oxide After chromium and zinc oxide were weighed in the ratios of Table 2, they were mixed with a ball of nylon and zirconia for 24 hours in a ball mill. Ethyl alcohol was used as a dispersion medium, and the mixed slurry was dried and calcined at 1150 ° C. for 5 hours. Ethyl alcohol was again used as a dispersion medium, pulverized and mixed for 2 hours using an Attrition Mill, dried, pressed into a mold having a diameter of 12.0 mm, and then subjected to isostatic molding. Thereafter, the molded specimen was fired in an atmosphere of air at a temperature of 1300 to 1450 ° C.

Its sintering temperature, dielectric constant and quality factor are also shown in Table 2.

Claims (10)

90 to 99 mol% of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4), and 0.5 to 5.0 mol% A high-frequency dielectric ceramic composition comprising magnesium oxide, 0.5 to 5.0 mol% tantalum oxide and 0.75 to 1.5 wt% zinc oxide. The method of claim 1, wherein the amount of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4) is 98.5 to 98. A mole% dielectric ceramic composition for high frequency. The dielectric ceramic composition for high frequency according to claim 1, wherein the amount of magnesium oxide is 1.0 to 1.5 mol%. The dielectric ceramic composition for high frequency according to claim 1, wherein the amount of tantalum oxide is 1.0 to 1.5 mol%. The dielectric ceramic composition for high frequency according to any one of claims 1 to 4, wherein x, y, z are x = 0.8, y = 0.2 and z = 1.0. 90 to 99 mol% of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4), and 0.5 to 5.0 mol% A high frequency dielectric ceramic composition comprising magnesium oxide, 0.5 to 5.0 mol% niobium oxide, and 0.75 to 1.5 wt% zinc oxide. The method according to claim 6, wherein the amount of (Zr _x Sn _y ) Ti _z O ₄ (x + y + z = 2, 0.6 ≦ x ≦ 1.0, 0 ≦ y ≦ 0.4, 0.6 ≦ z ≦ 1.4) is 98.5 to 98. A mole% dielectric ceramic composition for high frequency. 7. The dielectric ceramic composition for high frequency according to claim 6, wherein the amount of magnesium oxide is 0.75 to 1.25 mol%. 7. The dielectric ceramic composition for high frequency according to claim 6, wherein the amount of niobium oxide is 0.75 to 1.25 mol%. The dielectric ceramic composition for high frequency according to any one of claims 6 to 9, wherein x, y, and z are x = 0.8, y = 0.2 and z = 1.0.