JP3303525B2 - Dielectric porcelain material and dielectric resonator - 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 material and a dielectric resonator used as a material for a dielectric resonator and the like.

[0002]

2. Description of the Related Art In recent years, in the high-frequency region of microwaves or millimeter waves (hereinafter, these are collectively referred to as microwaves) having a wavelength of several centimeters or less, dielectric ceramic materials include dielectric resonators and high-frequency integrated circuit substrates. Has been widely used. By the way, in this kind of dielectric porcelain material,
a) The dielectric constant (εr) is large and stable. b) The no-load Q value (Qu) is high and the variation is small. c) It has been demanded that the temperature coefficient (τf) of the resonance frequency is small and it is easy to set a desired value with high accuracy. As a dielectric ceramic material satisfying this condition, a composite perovskite structure has been conventionally used. (A (B
_1/3 B _'2/3) oxide having the indicated are) at O ₃ has been studied extensively.

For example, in Japanese Patent Publication No. 2-53884, the general formula (1-x) Ba (Zn _1/3 Ta _2/3 ) O _{3 is used.}
When expressed as -xBa (Co _1/3 Nb _2/3 ) O ₃ , the component composition is in the range of 0 <x <1 in terms of mole fraction, and the relative dielectric constant (εr) is 31 as a characteristic. ~ 33, no load (Q
u) is 9420-10050, and the resonance frequency (τf) is −
A dielectric porcelain composition that achieves a characteristic value of 0.2 to -10.8 ppm / ° C is disclosed. A dielectric ceramic material made of this composition is incorporated as a bandpass filter or a local oscillator as a dielectric resonator, and has a frequency of 900 MHz to 1.5 G.
Hz mobile phone, mobile phone, etc. contribute to miniaturization, and further, 1.2GHz to 12GHz GPS
And temperature stabilization of frequency converters for satellite broadcasting and satellite communications.

[0004]

By the way, in the recent communication field, especially in the field of mobile communication, the output power of transmission / reception has been increased as the frequency of use becomes higher in the microwave band. . However, a filter made of a conventional dielectric porcelain material is restricted in use in this region due to heat generation, and is made of a material having a lower dielectric loss, that is, a material having a high unloaded Q value (Q = 1 / tan δ). In addition, a stable material having a small variation is desired.
Research on the application of dielectric resonators in the high-frequency range has also been actively conducted, and it has been found that the unloaded Q value is high, the temperature coefficient of resonance frequency (τf) is small, and a desired value can be set accurately. A stable material that is easy is desired.

However, in response to this demand, the conventional materials
In particular, the no-load Q value is about 10050 at the maximum, which is not yet sufficient in the microwave band, and there are variations in the characteristics. Further, when the temperature coefficient (τf) of the resonance frequency decreases, the no-load Q value decreases at the same time. It has been considered difficult to select a material that satisfies these two characteristics in the region.
One of the main causes is that the basic composition has Z
The n component is included, and the Zn component tends to evaporate easily during firing. As a result, a component imbalance occurs and a stable porcelain element is hardly obtained. It was to become.

In order to solve the above problems, the present invention has a high no-load Q value in a microwave region, a very small standard deviation (Δn−1) indicating a variation in the no-load Q value, and a relative dielectric constant. Rate (εr) is high and can be stabilized,
A dielectric porcelain material that has a small temperature coefficient (τf) of the resonance frequency of the resonator, can set a desired value with high accuracy, can improve the yield in manufacturing, and can greatly reduce the productivity cost. The purpose is to provide.

Another object of the present invention is to provide a dielectric resonator which can easily set a temperature coefficient (τf) value of a resonance frequency to a desired value with high accuracy.

[0008]

Means for Solving the Problems] The dielectric ceramic material of the present invention, in order to achieve the above object, the general formula Ba {Zn _1/3
(Nb _x Ta _(1-x) ) _2/3 ｝ O ₃ (where 0 <x <1) and Co ₃ as an additive component
It is characterized by adding 0.01 to 0.08% by weight of Co in terms of O ₄ . Here, Co carbonate, hydroxide,
Since oxides and the like become oxides after sintering, conversion into Co ₃ O ₄ means converting these amounts based on the amount of Co.

Further, there is provided a dielectric resonator using the above-mentioned dielectric porcelain material.

[0010]

[Function] General formula Ba {Zn _1/3 (Nb _x Ta _(1-x) ) _2/3 }
Since the composition represented by O ₃ (where 0 <x <1) is used as the basic composition, the relative dielectric constant (ε
r) can be increased. As an additive component, C
o ₃ O ₄ Co in the range of 0.01 to 0.08 wt% in terms of
Is added, the sinterability is improved over a wide firing temperature range even when there is a Zn component, the relative dielectric constant (εr) is increased and stabilized, the temperature coefficient (τf) of the resonance frequency is reduced, and the desired value is precisely obtained. Can be set. Further, it is possible to increase the no-load Q value and reduce the standard deviation value (Δn−1) representing the variation.

Further, by using a dielectric ceramic material, a dielectric resonator having a desired temperature coefficient (τf) within a required range can be manufactured.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dielectric ceramic material according to one embodiment of the present invention will be described in detail with reference to the following (Table 1) and (Table 2).

[0013]

[Table 1]

[0014]

[Table 2]

Table 1 shows that the basic composition is represented by the general formula Ba ｛Zn.
Co was added to the composition of _1/3 (Nb _x Ta _(1-x) ) _2/3 ｝ O ₃ (x = 0.06) as an additive component, and the amount of addition and the firing conditions were changed. 3 shows a dielectric ceramic material of one embodiment and its characteristic values.

Table 2 shows that the basic composition is represented by the general formula Ba ｛Zn.
Co was added as an additive component to the composition of _1/3 (Nb _x Ta _(1-x) ) _2/3 ｝ O ₃ (x = 0.04), and the amount of addition and firing conditions were changed. 3 shows a dielectric ceramic material of one embodiment and its characteristic values.

In order to compare the characteristics of the dielectric porcelain material of one embodiment of the present invention, the same 5 mm diameter and thickness 2
The measurement is performed using a cylindrical sample of mm. This can be used as a dielectric resonator described later.

Therefore, the procedure for preparing the sample will be described.
Note that the manufacturing is performed under common manufacturing conditions between the embodiments. Starting material
Is chemically pure BaCO_Three, ZnO, Nb_TwoO_Five, T
a_TwoO _Five, Co_ThreeO_Four, CoCO_Three, Co (OH)_Two, CoO
Using the raw material powders of
The composition is as shown in (Table 1) and (Table 2)
Calculate the blending amount to become 100% by weight of the basic composition
On the other hand, using the method of adding additives
After weighing a predetermined amount, each of those raw material powders is made of urethane
Pour into a pot mill with zirconia cobblestone and pure water
To perform a wet mixing process for 20 hours. And each mixture
After taking out and drying, put in alumina crucible and put in air
And calcined at 1100 ° C for 2 hours.
Calcined zirconia cobblestone in urethane pot mill
And 20 hours of wet grinding with pure water
is there. After filtering and drying the crushed mud, powder
7% polyvinyl alcohol as a binder
After adding 8% by weight of the solution to make it homogeneous, 32 mesh
Granulation through a sieve. The granulated powder is placed in the mold and hydraulic press.
800kg / cm molding pressure^Two13m in diameter
m, about 6 mm thick. Molded products with high purity
Put in magnesia pods and smell in air according to composition
For 20 hours at a temperature in the range of 1400-1550 ° C
And fired to obtain each dielectric ceramic material.

The characteristics of each dielectric ceramic material sample were measured as follows. The relative dielectric constant (εr) and the value of the unloaded Q value were measured using a known parallel conductor plate type dielectric resonator method. The standard deviation value (бn-1) indicating the variation of the no-load Q value is calculated using a statistical management method.
100 were calculated using the following equation (V = s / n-1, n-1 = √V). The temperature coefficient (τf) of the resonance frequency is −25 to
It was obtained by calculation from the temperature change of the resonance frequency in the temperature range of 75 ° C. And the resonance frequency is 10-12 GHz
And the results are shown in (Table 1) and (Table 2). Samples marked with * in Tables 1 and 2 are comparative examples outside the scope of the present invention.

(Table 1) As is clear from Table 1, sample numbers 3 to
7, 11 to 15 of the dielectric ceramic materials of the embodiments, the relative dielectric constant (εr) is high and stable, and the temperature coefficient (τf) of the resonance frequency is small. The no-load Q value shows a high value, and the standard deviation value (Δn-1) showing the variation is extremely small. Although the firing temperature was changed between 1530 ° C. and 1450 ° C. for the same composition, the effect of improving the characteristics was sufficiently obtained with the added amount within the range. In particular, the addition amount was good in the range of 0.02 to 0.04% by weight. For comparison, the materials of sample Nos. 1 and 9 did not contain Co ₃ O _{4 and} had a low unloaded Q value and a large standard deviation value (Δn−1). The effects of the materials of Sample Nos. 2 and 10 were slightly recognized when the amount of addition was 0.01% by weight or less, but the characteristics were not improved. The materials of Sample Nos. 8 and 16 showed a tendency that the relative dielectric constant (εr) was slightly increased when the amount of addition was large, but the temperature coefficient (τf) of the resonance frequency became largely negative and shifted to the negative side. Further, the no-load Q value is low, and the standard deviation value (Δn-1) is also large, which is not preferable because it varies.

Next, in the examples shown by the materials of sample Nos. 17 to 19, Co-added components other than Co ₃ O ₄ are added in an amount of 0.01 to 0.1.
Each of the compounds added in an amount within the range of 08% by weight shows good characteristic values. This is 0.1 in terms of Co ₃ O ₄ .
04% by weight respectively. This is a good result because Co carbonates, hydroxides, oxides, and the like become oxides after firing, so that the initial form of the added component is considered to have little effect.

(Table 2) As is clear from Table 2, sample No. 22
In the examples shown by the materials of 26 to 30, 34 to 36, and 36 to 38, the relative dielectric constant (εr) is stable. The temperature coefficient (τf) of the resonance frequency also slightly shifts to the negative side with the addition amount, but is stable. Further, the no-load Q value shows a high value, and the standard deviation value (бn−1) showing the variation.
Is getting smaller.

In the examples shown by the materials of sample Nos. 36 to 38, any of the Co-added components other than Co ₃ O ₄ was added in the added amount within the range, and all showed good characteristic values. This was obtained by adding 0.04% by weight in terms of Co ₃ O ₄ . The material of Sample Nos. 20 and 28 for comparison was Co ₃
With no added O ₄ , the no-load Q value was low and the standard deviation (Δn−
1) is large. Further, the materials of Sample Nos. 21 and 29 have an addition amount of 0.01% by weight or less, and the effect is slightly recognized but the characteristic value is not improved. The materials of Sample Nos. 27 and 35 show a tendency that the temperature coefficient (τf) of the resonance frequency becomes largely negative and shifts to the negative side when the amount of addition is large. In addition, the no-load Q value is low and the standard deviation value (Δn-1) is large, which is not preferable.

As described above, since 0.01% to 0.08% by weight of Co is added as an additional component in terms of Co ₃ O ₄ , the sinterability of the porcelain material is improved. This is because Z in the base composition
This is considered to be because Co prevents evaporation of the n component. This makes the relative permittivity (εr) high and stable,
It becomes easy to set the temperature coefficient (τf) of the resonance frequency to a small value and to a desired value with high accuracy. No load Q
The standard deviation value (Δn−1) having a high value and showing the variation is small and stable.

Next, a dielectric resonator according to an embodiment of the present invention using the above-described dielectric ceramic material will be described.
FIG. 1 is a perspective view of a dielectric resonator according to one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a dielectric resonator main body. The dielectric resonator body 1 is formed using the above-described dielectric ceramic material, and has a columnar shape. Its characteristics are 5
When the diameter is 2 mm and the thickness is 2 mm (Table 1), the data in Table 2 are as shown. Reference numeral 2 denotes a glass bonding layer for bonding the dielectric resonator main body 1 and the support 3 made of forsterite ceramic material. The glass material used for the glass bonding layer 2 has a coefficient of thermal expansion that is the same as the coefficient of thermal expansion of the dielectric porcelain material used for the dielectric resonator body 1 and the coefficient of thermal expansion of the forsterite porcelain material used for the support 3. They are almost similar, and are bonded at a joining temperature of 800 ° C. using a silicate-based material for the purpose of preventing cracks during joining. The support 3 is for holding the dielectric resonator body 1, and the forsterite porcelain material used for the support 3 is a cylindrical material having a high unloaded Q value in a microwave band region.

In this embodiment, the dielectric resonator body 1 has a columnar shape as described above, and its resonance mode is generally known as TE.
01δ is adopted. The cylindrical shape of this dimension has a resonance frequency of about 12 GHz. In addition, as the shape of the dielectric resonator main body 1, there are a cylindrical coaxial resonator, a plate-shaped strip line resonator, and the like. The resonance mode is TEM, and these have a relatively low resonance frequency.
Since it is in the 10 MHz band, which is higher than the 0 MHz band, it can be used for car phones, mobile phones, and even satellite broadcasting.

The dielectric resonator of this embodiment has a high unloaded Q value in the microwave region, and has a temperature coefficient (τ
Since f) can be selected, it is useful for stabilizing the temperature compensation action of the circuit when combined with other components such as a semiconductor, and a compact, high-performance filter or oscillator can be manufactured.
The dielectric ceramic material of the present invention is useful not only for a dielectric resonator but also for a high-frequency substrate or the like.

[0029]

As described above, according to the present invention,
Since the composition represented by the general formula Ba ｛Zn _1/3 (Nb _x Ta _{(1-x )} ) _2/3 ｝ O ₃ (where 0 <x <1) is used as the basic composition, in the microwave region The relative dielectric constant (εr) can be increased. Further, since Co is added as an additive component in the range of 0.01 to 0.08% by weight in terms of Co ₃ O ₄ , sinterability is improved over a wide firing temperature range even if there is a Zn component, and the characteristic value is as follows. In a high frequency band such as 10 to 12 GHz, the relative dielectric constant (εr) is high and stabilized, the temperature coefficient (τf) of the resonance frequency is small, and it is easy to accurately set the desired value. Furthermore, the no-load Q value is extremely high at 12000 or more, and the standard deviation value (Δn−1) showing the variation can be made small and a stable value can be provided.

Further, since the firing temperature can be lowered, the sinterability of the porcelain material is improved, and the yield at the time of manufacturing and the reduction of the manufacturing cost can be greatly improved. is there.

The dielectric resonator is made of a dielectric porcelain material so that the temperature coefficient of the resonance frequency (τ
The dielectric resonator having the feature (f) can be manufactured and is of great value.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dielectric resonator according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric resonator main body 2 Glass bonding layer 3 Support base

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuya Fujimaru 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-55-56063 (JP, A) JP-A-63- 303844 (JP, A) JP-A-64-60905 (JP, A) JP-A-4-338154 (JP, A) SYUNNICHIRO KAWAS HIMA, AMERICA CERA MIC SOCIETY BULLET IN, Vol. 72, No. 5, MAY 1993, p. 120-126 (58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 3/12 312 C04B 35/495 H01P 7/10

Claims (2)

(57) [Claims] 1. The general formula Ba ｛Zn _1/3 (Nb _x Ta _(1-x) )
_2/3 ｝ O ₃ (where 0 <x <1), and 0.01 to _{3 in} terms of Co ₃ O ₄ as an additive component with respect to the basic composition represented by 0 <x <1.
A dielectric ceramic material to which 0.08% by weight of Co is added. 2. A dielectric resonator made of the dielectric ceramic material according to claim 1.