JP2965417B2 - Dielectric porcelain composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition suitable for a dielectric resonator and a dielectric filter used in a high frequency region such as a microwave and a millimeter wave band.

[0002]

2. Description of the Related Art Hitherto, dielectric materials have been applied to impedance matching of circuits, dielectric resonators, filters, and the like in the high frequency region. There is a demand for the development of a dielectric having a small fluctuation in the resonance frequency due to the above.

As a dielectric porcelain composition, Japanese Patent Application Laid-Open No.
No. 60544 discloses xBaO.yMgO.zTa ₂ O ₅
A system has been proposed. This material has a high unloaded Q factor and a small rate of temperature change at the resonant frequency.

[0004]

However, in the above-mentioned conventional composition, since the Q value has a large variation, there is a problem in practical use such as a decrease in manufacturing yield and an increase in variation in characteristics when mounted on a device.

An object of the present invention is to provide a dielectric ceramic composition having a small Q value and a large Q value in order to solve the above-mentioned problems of the prior art.

[0006]

In order to solve the above-mentioned problems, the first dielectric ceramic composition of the present invention comprises BaO,
MgO, TaO _2.5, the dielectric ceramic composition containing _{ZrO 2, Ba (Zr x Mg} y Ta z) when expressed as _w O _n (n is an arbitrary number), x + y + z = 1,0.001 ≦ x
≦ 0.02, 0.292 ≦ y ≦ 0.335, 0.664 ≦ z ≦ 0.688, and 0.97 ≦ w ≦ 0.998.

Next, a second dielectric porcelain composition of the present invention is a dielectric porcelain composition containing BaO, MgO, CoO, TaO _2.5 and ZrO ₂ , wherein Ba [Zr _x (Mg
_{1-v Co v) y Ta} z] when expressed as _w O _n (n is an arbitrary number), x + y + z = 1,0.001 ≦ x ≦ 0.025, 0.28
7 ≤ y ≤ 0.335, 0.665 ≤ z ≤ 0.689, 0.01 ≤ v ≤ 0.2
5, and a configuration in which 0.97 ≦ w ≦ 0.998.

[0008]

According to the first and second dielectric ceramic compositions of the present invention, the variation of the unloaded Q value is extremely small,
In addition, a high-quality porcelain having a high Q value and a good temperature change rate of the resonance frequency can be obtained.

[0009]

The present invention will be described more specifically with reference to the following examples.
explain. Example 1 As a starting material, chemically high purity BaCO_Three, ZrO
_Two, MgO, Ta_TwoO _FiveUsing the specified
Weighed into the composition and wet-mixed using a ball mill.
Processed. The mixture is dried and calcined at 800 ° C. for 2 hours.
After calcination, this calcined powder is further pulverized with a ball mill.
After dehydration and drying, polyvinyl alcohol is used as a binder.
Add an appropriate amount, 1 ton / cm^TwoPressure of 8
mm and a 4 mm thick disk.

The molded body is heated at 1500 to 1550 ° C. for 12 hours.
The sintering was performed for a time to obtain a porcelain sample. The calcination was carried out in a state in which 20 specimens of the same composition were placed in a platinum container sufficiently filled with the calcined powder of the same composition in consideration of the evaporation of the components at high temperatures.

For 20 porcelain samples for each composition,
Relative permittivity at a frequency of 10 GHz: ε _r , no load:
± 5% of the average value of no-load Q as an index of Q and variation
%, And the temperature change rate of the resonance frequency at -50 ° C to 50 ° C: τ _f (ppm / ° C) was measured. In addition, ε _r , Q, and τ _f were used as test data by calculating an average of 20 values (Table 1).

[0012]

[Table 1]

As is apparent from Table 1, Ba and Ba at w = 1
With a composition having a composition ratio of 1: 1 other than the above, there are a large number of samples in which the variation of the Q value is large and does not fall within ± 5%. In the region where w is smaller than 1 according to the present embodiment, excellent characteristics were obtained with small variations. Further, when the composition ratio (w) other than Ba and Ba is higher than 1: 1 composition, it is not preferable.

[0014] Further, even when the composition does not contain ZrO ₂ at x = 0, the variation of the Q value is large, and the variation can be suppressed by including ZrO ₂ . Further, when the composition is x> 0.02, τ _f is sharply increased, when the composition is z> 0.688, the sinterability is poor, and when the composition is z <0.664, the Q value is remarkably reduced, which is not practical.

In the composition range according to this embodiment, the Q value is 20,000 or more for any composition, the variation of the Q value with respect to the average of 20 samples is ± 5% or less, and the temperature change rate of the resonance frequency is 4 ppm / It was confirmed that the film had very good electrical characteristics of not more than ℃.

Example 2 As a starting material, chemically high-purity BaCO ₃ , ZrO
_2, MgO, CoO, using the Ta ₂ O _5. Next, Table 2
Was weighed to a predetermined composition shown in Table 2, and this was subjected to wet mixing treatment using a ball mill. Hereinafter, test samples were obtained in the same manner as in Example 1. Table 2 shows the relative permittivity at a frequency of 10 GHz for each composition: ε _r , the no-load Q: Q, the number of samples that do not fall within ± 6% of the average value of the no-load Q as an index of variation: S, and −50. It shows the temperature change rate of the resonance frequency from ℃ to 50 ℃: τ _f (ppm / ℃). Note that ε _r , Q, τ
_{For f,} the average value of 20 samples was calculated and used as test data (Table 2).

[0017]

[Table 2]

As is clear from Table 2, as in Example 1, the Q value was determined for a composition in which the composition ratio of Ba to Ba was 1: 1 except for w = 1 and a composition containing no ZrO ₂ at x = 0. Was large.

Other behaviors are the same as in the first embodiment,
In this embodiment, τ _f is good up to a composition of x ≧ 0.025,
The composition range in which τ _f is smaller than in Example 1 is widened. Also,
Since τ _f and ε _r change according to the amount of Co while maintaining a high Q value in the composition of v <0.25, the required τ _f for any ε _r can be obtained by controlling the composition.

A high-frequency device using a dielectric porcelain may have a temperature dependency generated from the device itself,
In this case, it is necessary to compensate for the temperature dependence of the whole by the temperature dependence of the dielectric while maintaining the dielectric constant of the porcelain required for the device. Therefore, controlling τ _f for an arbitrary ε _r is extremely useful in designing a high-frequency device having no temperature dependence.

In the composition range according to this embodiment, the Q value is 20,000 or more for any composition, the variation of the Q value with respect to the average of 20 samples is ± 6% or less, and the temperature change rate of the resonance frequency is 2 ppm / It has very good electrical characteristics of less than ℃.

[0022] As described above, according to this embodiment, the composition formula _{Ba (Zr x Mg y Ta z} ) w O n specific x in the dielectric ceramic composition represented by, y, in the range of z, B
The composition ratio other than a and Ba is slightly smaller than 1, especially 0.1.
By being in the range of 97 ≦ w ≦ 0.998,
The variation of the Q value is extremely small and has a high Q value,
Further, it is possible to obtain a high-quality dielectric porcelain having a good temperature change rate of the resonance frequency. Further, it is useful for a dielectric ceramic composition suitable for a dielectric resonator and a dielectric filter used in a high frequency region such as a microwave and a millimeter wave band.

[0023]

As described above, according to the present invention, the variation of the no-load Q value is extremely small, the Q value is high, and the high-quality dielectric material having a good temperature change rate of the resonance frequency is obtained. It becomes possible to obtain a body porcelain.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-105107 (JP, A) JP-A-1-124272 (JP, A) JP-A-5-198210 (JP, A) (58) Investigation Field (Int.Cl. ⁶ , DB name) H01B 3/12 312 C04B 35/495 H01P 7/10

Claims (2)

(57) [Claims] 1. BaO, MgO, TaO _2.5 , ZrO ₂
In a dielectric porcelain composition containing: Ba (Zr _x Mg _y)
Ta _z) when expressed as _w O _n (n is an arbitrary number), x +
y + z = 1, 0.001 ≦ x ≦ 0.02, 0.292 ≦ y ≦ 0.335,
A dielectric ceramic composition in which 0.664 ≦ z ≦ 0.688 and 0.97 ≦ w ≦ 0.998. 2. BaO, MgO, CoO, TaO _2.5 ,
In a dielectric porcelain composition containing ZrO ₂ , Ba [Zr
_{x (Mg 1-v Co v} ) y Ta z] when expressed as _w O _n (n is an arbitrary number), x + y + z = 1,0.001 ≦ x ≦ 0.02
5, 0.287 ≤ y ≤ 0.335, 0.665 ≤ z ≤ 0.689, 0.01 ≤
A dielectric ceramic composition in the range of v ≦ 0.25 and 0.97 ≦ w ≦ 0.998.