JP3347576B2 - High frequency dielectric ceramic composition 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 high frequency dielectric composition used in a high frequency region such as a microwave, a millimeter wave, etc. High frequency dielectric ceramic composition useful as material for circuit element substrate, dielectric resonator support, dielectric resonator, dielectric waveguide, dielectric antenna, etc. used in band, and support for dielectric ceramic The present invention relates to a dielectric resonator fixed to a substrate via a substrate.

[0002]

2. Description of the Related Art In high frequency circuit elements such as microwave and millimeter wave integrated circuits, a structure in which a dielectric resonant ceramic is fixed to a substrate via a support member may be adopted. For example, as shown in FIG. 1, a dielectric resonator control type microwave transmitter attaches a dielectric porcelain 1 to a porcelain substrate 3 via a support member 2, and an electromagnetic field H leaking out of the dielectric porcelain 1.
The structure is such that they are connected to a strip line 4 provided on the porcelain substrate 3 by utilizing the above, and these are accommodated in a metal case 5.

In this type of high-frequency circuit, a resonance system with a high no-load Q is formed by controlling the electric field of the dielectric ceramic 1 from leaking through the support member 2. No. 2 has a low dielectric constant and a dielectric loss (ta
It is necessary to use a material having a small nδ) (a large Q value). For this reason, conventionally, the relative permittivity of the support member material is about 7, and the Q value at the measurement frequency of 10 GHz is about 15,000.
Is used as the material of the porcelain substrate 3 and has a relative dielectric constant of about 10 and a measurement frequency of 10
Alumina porcelain having a Q value of 20,000 or more at GHz has been adopted (for example, see JP-A-62-103904). On the other hand, cordierite is conventionally known as a material having a low relative dielectric constant. However, since the firing temperature range is extremely narrow, it is difficult to obtain a dense sintered body. By adding a glass material, the relative dielectric constant is 4 to 6, and the measurement frequency is 10 GH.
Glass ceramics having a Q value of about 1000 at z are known (see, for example, JP-A-61-234128).

[0004]

However, the relative dielectric constants of alumina and forsterite which have been conventionally used are about 10 and about 7, respectively, and with the recent widespread use of high frequency band dielectric resonators. Therefore, a material having a lower dielectric constant has been demanded.

On the other hand, porcelain such as glass ceramic used as a low dielectric constant material has a relative dielectric constant as small as about 4 to 6, but has a Q value of about 1000 at 10 GHz, and has a high dielectric constant in recent years. With the spread of resonators, a low Q material having a higher Q value has been demanded.

Alumina porcelain mainly used for a porcelain substrate of a resonator has a relatively high relative dielectric constant of about 10, and the line width becomes too small to form a high impedance strip line (usually). (1 μm or less), there is a problem that the disconnection occurs, the relative variation in the line width increases, and the defective rate of the microwave integrated circuit increases.

On the other hand, if the thickness of the substrate is constant, the impedance of the strip line in this type of porcelain substrate is inversely proportional to the relative dielectric constant and the width of the strip line. By using a substrate material having a low relative dielectric constant, the impedance can be increased, and therefore, a material having a lower dielectric constant has been demanded.

As one means for solving the above problem, the present inventors have proposed a composite oxide comprising Mg, Al, and Si as metal elements, wherein the molar ratio composition formula of each metal element oxide is xMgO-yAl _2. When expressed as O ₃ -zSiO ₂ , x, y, and z are 10 ≦ x ≦ 40, 10 ≦ y ≦ 40,
0 ≦ z ≦ 80, x + y + z = 100, relative permittivity is 6 or less, and Q value at a measurement frequency of 10 GHz is 20
We have already proposed a dielectric ceramic composition for a high frequency of at least 00 and a dielectric resonator (Japanese Patent Application No. 7-195211).
issue).

This dielectric ceramic composition for high frequency was excellent, having a lower dielectric constant than alumina and forsterite, and having a higher Q value than glass ceramic. However, conventionally, since the firing temperature range of cordierite is extremely narrow, it has been difficult to obtain a dense sintered body, and the dielectric ceramic composition for high frequency application previously filed by the inventors was no exception.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-frequency dielectric ceramic composition and a dielectric resonator having a low dielectric constant, a high Q value at a measurement frequency of 10 GHz, and capable of improving firing conditions. .

[0011]

The high frequency dielectric ceramic composition of the present invention comprises Mg, Al, Si and N as metal elements.
High frequency dielectric consisting of i or Co and unavoidable impurities
A body porcelain composition, moles of composite oxide of the respective metal elements
When the specific composition formula is expressed as xMgO-yAl ₂ O ₃ -zSiO ₂ , x, y, and z are 10 ≦ x ≦ 40 and 10 ≦ y ≦ 4.
In the main component satisfying 0, 20 ≦ z ≦ 80, x + y + z = 100, Ni or Co is converted to NiO,
It contains 0.1 to 15% by weight in terms of O. In the present invention, the relative dielectric constant is 6 or less and the measurement frequency is 10 GH.
The Q value at z is 3000 or more. Further, in a dielectric resonator having a dielectric ceramic fixed on a substrate via a support member, the substrate and / or the support member are made of the above-described dielectric ceramic composition.

[0012]

In the dielectric ceramic composition for a high frequency wave of the present invention, sintering conditions such as sintering temperature and the like are strictly controlled by containing a predetermined amount of Ni or Co with respect to the above-mentioned main components in NiO conversion and CoO conversion, respectively. The firing conditions can be improved without greatly deteriorating the characteristics obtained by the above.
That is, Q at a relative dielectric constant of 4 to 6 and a measurement frequency of 10 GHz.
In addition to obtaining a low dielectric constant value of 3000 or more, for example, a firing temperature range of about 10 ° C. can be improved to about 100 ° C., thereby facilitating production and improving mass productivity. can do.

Further, by using such a dielectric ceramic having a low dielectric constant and a high Q value for a support member and / or a substrate of a dielectric resonator, for example, a high impedance microwave integrated circuit or the like can be obtained. Can be manufactured without deteriorating the reliability.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The dielectric ceramic composition for a high frequency wave of the present invention has a molar ratio composition formula of xMgO-yAl ₂ O ₃ -zS
When expressed as iO ₂ , x, y, and z are 10 ≦ x ≦ 40,
10 ≦ y ≦ 40, 20 ≦ z ≦ 80, x + y + z = 100
Those satisfying the above are the main components.

The main component composition of the dielectric ceramic composition for high frequencies of the present invention is limited to the above range for the following reasons. That is, when x indicating the molar percentage of MgO is set to 10 to 40 mol%, if less than 10 mol%, a good sintered body cannot be obtained and Q
This is because when the value is low, and when it exceeds 40 mol%, the relative dielectric constant increases. In particular, x indicating the amount of MgO indicates that the Q value is 500
From the viewpoint of 0 or more, 15 to 35 mol% is desirable.

The reason why y indicating the molar percentage of Al ₂ O ₃ is set to 10 to 40 mol% is that when the amount y of Al ₂ O ₃ is smaller than 10 mol%, a good sintered body can be obtained. This is because the Q value is low, and when it exceeds 40 mol%, the relative dielectric constant is high. Y indicating the amount of Al ₂ O ₃ indicates that the Q value is 5;
From the viewpoint of being 000 or more, 17 to 35 mol% is desirable.

When the molar percentage z of SiO ₂ is 20 ≦ z ≦ 80
The reason for using mol% is that when z is less than 20 mol%, the relative dielectric constant increases, and when z exceeds 80 mol%, a good sintered body cannot be obtained and the Q value decreases. SiO ₂
Z indicating the quantity is 3 from the viewpoint that the Q value is 5000 or more.
0-65 mol% is desirable.

According to the present invention, the main component is Ni
Or Co in NiO conversion and CoO conversion in 0.1
-15% by weight. Ni or Co is 0.1-15% by weight in NiO conversion and CoO conversion respectively
The reason for this is that if the amount is less than 0.1% by weight, the densification firing temperature does not become wide, and if it is more than 15% by weight, the dielectric loss increases and the Q value decreases. As the content of Ni or Co increases, the densification firing temperature increases, but the relative dielectric constant increases, and the Q value decreases.From the viewpoint of the balance between these characteristics and the densification firing temperature, It is desirable to determine the content of Ni or Co.

The high frequency dielectric ceramic composition of the present invention has a Q
To make the value 5000 or more, 15 ≦ x ≦ 35, 17
≤ y ≤ 35 and 30 ≤ z ≤ 70, and in order to make the Q value 7000 or more, 20 ≤
It is desirable to satisfy x ≦ 30, 17 ≦ y ≦ 30, and 40 ≦ z ≦ 60. In the present invention, in particular, the composition of cordierite, ie, x = 22.2, y = 22.2, z = 55.6.
Ni or Co in NiO conversion, CoO conversion in 0.1 ~
It is desirable to contain 10% by weight.

The Q value at the measurement frequency of 10 GHz is 3000
The reason for satisfying the above is that when the Q value is 3000 or more, it is possible to sufficiently cope with recent high-frequency band dielectric resonators. The Q value is preferably as high as possible, but in particular, the measurement frequency is 10 GHz.
Is preferably 5000 or more.

In the dielectric ceramic composition for high frequency waves of the present invention, the main crystal phase is cordierite, and other crystal phases include mullite, spinel, protoenstatite,
Clinoenstatite, cristobalite, forsterite, tridymite, safarin and the like may be precipitated, but the precipitated phase differs depending on the composition.

Further, as shown in FIG. 1, the dielectric resonator of the present invention comprises a dielectric ceramic 1 on a substrate 3 via a support member 2.
Is fixed, and the support member 2 or the substrate 3 or the support member 2 and the substrate 3 are made of the above-described dielectric ceramic composition. In this case, a known material is used for the dielectric porcelain 1. As the dielectric ceramic 1, the dielectric ceramic composition of the present invention may be used.

The dielectric porcelain of the present invention comprises
For example, MgCO ₃ powder, Al ₂ O ₃ powder, SiO ₂ powder, NiO powder or CoO powder are weighed at a predetermined ratio, wet-mixed and dried, and this mixture is temporarily heated at 1100 to 1300 ° C. in the atmosphere. After baking, pulverize.
It is obtained by adding an appropriate amount of a binder to the obtained powder and molding, and firing this molded body at 1300 to 1400 ° C in the air.

The raw material powder made of a metal element such as Mg, Al, Si, Ni, and Co can be made of any of inorganic compounds such as oxides, carbonates and acetates, or organic compounds such as organic metals by firing. What is necessary is just to be formed as an oxide.

The main component of the dielectric ceramic composition of the present invention is Mg, Al, Si, Ni or C as a metal element.
and, for example, Ca, Ba, Zr, Ni, Fe, Cr, P, N
Although a, Ti and the like may be mixed in this case, a ceramic having a low dielectric constant and a high Q value can be obtained as long as the above composition is satisfied.

In the dielectric ceramic composition of the present invention, if a low dielectric constant and a high Q value are required, for example, a circuit element substrate, a dielectric ceramic of a dielectric resonator, a dielectric waveguide Any material such as a dielectric antenna and the like can be applied, but as described above, it is most suitable for a support member or a substrate of a dielectric resonator.

[0027]

【Example】

Example 1 99% pure MgCO ₃ , 99.7 purity as raw material powder
% Al ₂ O ₃ , 99.4% pure SiO ₂ powder, and 99.9% pure NiO powder.
Was weighed so as to have the composition shown in Table 2, wet-mixed for 15 hours, and dried.
After calcining for an hour, it was pulverized. In Table 1, MgCO
₃ was converted to MgO.

An appropriate amount of a binder was added to the obtained powder and granulated, and this was molded under a pressure of 1000 kg / cm ² to obtain a molded body having a diameter of 12 mm and a thickness of 8 mm. The molded body was fired in the atmosphere at 1300 to 1550 ° C. for 2 hours to produce a porcelain, which was polished to obtain a dielectric porcelain sample having a diameter of 10 mm and a thickness of 6 mm.

Using these samples, the relative dielectric constant and Q value at a frequency of 10 GHz were measured by the dielectric cylinder resonator method, and the results are shown in Table 1.

[0030]

[Table 1]

According to Table 1, the dielectric ceramic composition for high frequencies according to the present invention has a low relative dielectric constant of 5.9 or less and a high Q value of 3100 or more at a measurement frequency of 10 GHz. I understand. Also, it can be seen that the range of the firing temperature is expanded as the Ni content is increased.

FIG. 2 shows an X-ray diffraction chart of the sample No. 11. From FIG. 2, in addition to cordierite,
It turns out that spinel has precipitated.

Example 2 MgCO _{3 having} a purity of 99% and a purity of 99.7 as a raw material powder
% Al ₂ O ₃ , 99.4% pure SiO ₂ powder, and 99.9% pure CoO powder.
Was weighed so as to have the composition shown in Table 2, wet-mixed for 15 hours, and dried.
After calcining for an hour, it was pulverized. In Table 2, MgCO
₃ was converted to MgO.

An appropriate amount of a binder was added to the obtained powder and granulated, and this was molded under a pressure of 1000 kg / cm ² to obtain a molded body having a diameter of 12 mm and a thickness of 8 mm. The molded body was fired in the air at 1300 to 1580 ° C. for 2 hours to produce a porcelain, which was then polished to a diameter of 10 mm and a thickness of 6 m.
m dielectric ceramic samples were obtained.

Using these samples, the dielectric constant and Q value at a frequency of 10 GHz were measured by the dielectric cylinder resonator method, and the results are shown in Table 2.

[0036]

[Table 2]

According to Table 2, the dielectric ceramic composition for high frequencies according to the present invention has a low relative dielectric constant of 5.8 or less and a high Q value of 3000 or more at a measurement frequency of 10 GHz. I understand. Further, it can be seen that the range of the sintering temperature also increases as the Co content increases.

FIG. 3 shows an X-ray diffraction chart of Sample No. 37. From FIG. 2, in addition to cordierite,
It turns out that spinel has precipitated.

[0039]

The high frequency dielectric ceramic composition of the present invention has a low relative dielectric constant of 6 or less, and maintains a high Q value of 3000 or more at 10 GHz. Range can be expanded, and productivity can be improved. For example, a high-frequency circuit element such as a high-impedance microwave integrated circuit can be manufactured without deteriorating the reliability by using it for a support member or a substrate of a dielectric resonator. In addition, since it has a low dielectric constant and a high Q value, for example, a substrate for a circuit element used in a microwave or millimeter wave band such as a microwave or a millimeter wave integrated circuit, a support for a dielectric resonator, a dielectric resonator, It is optimal as a material for dielectric waveguides, dielectric antennas and the like.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a dielectric resonator control type microwave transmitter showing an example of a high-frequency circuit element.

FIG. 2 shows sample Nos. 11 is an X-ray diffraction diagram showing the crystal structure of Sample No. 11.

FIG. 3 shows sample Nos. 37 is an X-ray diffraction diagram showing a crystal structure of 37. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dielectric porcelain 2 ... Support member 3 ... Porcelain board

Claims (3)

(57) [Claims] 1. A metal element comprising Mg, Al, Si and Ni
Or high frequency dielectric consisting of Co and unavoidable impurities
A porcelain composition, wherein the molar ratio of the composite oxide of each metal element is
When the composition formula is expressed as xMgO-yAl ₂ O ₃ -zSiO ₂ , the main components satisfying the following condition: x ≦ y ≦ z 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100 Ni or Co
A high frequency dielectric ceramic composition containing 0.1 to 15% by weight in terms of O and CoO. 2. A device having a relative dielectric constant of 6 or less and a measurement frequency of 10
The high frequency dielectric ceramic composition according to claim 1, wherein the Q value at GHz is 3000 or more. 3. A dielectric resonator in which a dielectric porcelain is fixed on a substrate via a supporting member, wherein said substrate and / or said supporting member is composed of Mg, Al, Si as a metal element.
A composite oxide comprising, when the composition formula of the molar ratio of an oxide of each metal element expressed as _{xMgO-yAl 2 O 3 -zSiO 2} , wherein x, y, z is 10 ≦ x ≦ 40 10 ≦ In the main component satisfying y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100, Ni or Co is Ni, respectively.
A dielectric resonator containing 0.1 to 15% by weight in terms of O and CoO.