JP3220359B2 - 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 ceramic composition used at a high frequency such as a microwave and a millimeter wave, and relates to a microwave and a millimeter wave such as a microwave and a millimeter wave integrated circuit. High frequency dielectric ceramic compositions useful as materials for circuit element substrates, dielectric resonator supports, dielectric resonators, dielectric waveguides, dielectric antennas, etc. used in the band, and supports for dielectric ceramics 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 porcelain is fixed to a substrate via a supporting member may be adopted. For example,
As shown in FIG. 1, a dielectric resonator control type microwave transmitter includes a dielectric ceramic 1 and a ceramic substrate 3
And is coupled to a strip line 4 provided on the porcelain substrate 3 by utilizing an electromagnetic field H leaking out of the dielectric porcelain 1 and 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 porcelain 1 from leaking through the support 2. No. 2 has a low dielectric constant and a low dielectric loss (tan).
It is necessary to use a material having a small δ) (a large Q value). For this reason, conventionally, forsterite having a relative dielectric constant of about 7 and a Q value of about 15,000 at a measurement frequency of 10 GHz has been employed as a material of the supporting member, and a dielectric constant of about 10 Measurement frequency 10GH
Alumina porcelain having a Q value of 20,000 or more in z has been employed (see, for example, JP-A-62-103904).

On the other hand, as a material having a low relative dielectric constant, a glass ceramic having a relative dielectric constant of 4 to 6 and a Q value of 2000 or less at a measurement frequency of 10 GHz has been known (for example, Japanese Patent Application Laid-Open No. Sho 61-61). No. 234128).

[0005]

However, the relative dielectric constants of alumina and forsterite, which have been conventionally used, are about 10 and about 7, respectively. Therefore, a material having a lower relative dielectric constant has been demanded.

On the other hand, porcelain such as glass ceramic used as a low dielectric constant material has a small relative dielectric constant of about 4 to 6, a Q value of 2000 or less at 10 GHz, and a dielectric resonance in a high frequency band in recent years. With the widespread use of devices, a low Q material having a higher Q value has been demanded.

Alumina porcelain, which is 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 disconnection occurs, the relative line width varies greatly, and the defect rate of the microwave integrated circuit increases. On the other hand, the impedance of the strip line in this type of porcelain substrate is inversely proportional to the relative permittivity and the width of the strip line, respectively, if the substrate thickness is constant. By using a substrate material having a low dielectric constant, the impedance can be increased, and therefore, a material having a lower dielectric constant has been demanded.

It is an object of the present invention to provide a high frequency dielectric ceramic composition having a lower dielectric constant than alumina and forsterite and a higher Q value than glass ceramic.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, M
g, Al, made of Si only, xMgO-yAl ₂ O ₃ -zSiO the molar ratio composition formula of an oxide of these elements
_If x, y, and z are constant values when expressed as ₂ ,
The present inventors have found that it is possible to obtain a dielectric ceramic composition for high frequencies having a lower dielectric constant than alumina and forsterite and a higher Q value than glass ceramic, and have reached the present invention.

That is, the dielectric ceramic composition for high frequencies of the present invention is a composite oxide composed of Mg, Al, and Si as metal elements, and the molar ratio composition formula of each metal element is xMgO-yAl _2. When expressed as O ₃ -zSiO ₂ , the x, y, and z are 10 ≦ x ≦ 40, 10 ≦ y ≦ 40, 20 ≦
z ≦ 80, x + y + z = 100, the relative dielectric constant is 6 or less, and Q at a measurement frequency of 10 GHz.
The value is 2000 or more.

Further, the dielectric resonator according to the present invention is a dielectric resonator in which a dielectric ceramic is fixed on a substrate via a supporting member, wherein the supporting member and / or the substrate has Mg, Al as a metal element. , A composite oxide comprising Si,
The molar ratio composition formula of the oxide of each metal element is xMgO-y
When expressed as Al ₂ O ₃ -zSiO ₂ , the x, y, and z are 10 ≦ x ≦ 40, 10 ≦ y ≦ 40, 20 ≦ z ≦ 80, x
+ Y + z = 100, the relative dielectric constant is 6 or less, and the Q value at the measurement frequency of 10 GHz is 2,000.
That's all.

[0012]

The dielectric ceramic composition of the present invention has a relative dielectric constant of 4
6, a high-impedance microwave integration using a low-permittivity and high-Q dielectric ceramic having a Q value of 2000 or more at a measurement frequency of 10 GHz for a support member or a substrate of a dielectric resonator, for example. High-frequency circuit elements such as circuits can be manufactured without loss of reliability.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The components of the high frequency dielectric ceramic composition of the present invention are limited to the above ranges for the following reasons. That is, the reason why x indicating the molar percentage of MgO is set to 10 to 40 is that if it is less than 10, a good sintered body cannot be obtained and the Q value is low, and if it exceeds 40, the relative dielectric constant becomes high. In particular, x indicating the amount of MgO is preferably 15 to 35 from the viewpoint that the Q value is 5000 or more.

Further, to that 10 to 40 and y indicating the molar percentage of Al ₂ O ₃ is, when the amount of Al ₂ O ₃ y is less than 10 is not good sintered body can be obtained and This is because the Q value decreases, and when the Q value exceeds 40, the relative dielectric constant increases. The value of y indicating the amount of Al ₂ O ₃ is preferably from 15 to 35 from the viewpoint that the Q value is 5000 or more.

When the molar percentage z of SiO ₂ is 20 ≦ z ≦ 80
The reason is that when z is smaller than 20, the relative permittivity becomes large, and when z exceeds 80, a good sintered body cannot be obtained and Q
The value decreases. Z indicating the amount of SiO ₂ indicates that the Q value is 5000
From the viewpoint of the above, 30 to 70 is desirable.

The dielectric ceramic composition for a high frequency wave of the present invention has Q
To make the value 5000 or more, 15 ≦ x ≦ 35, 15
≤ 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.

When the Q value at a measurement frequency of 10 GHz is 2000
The reason for satisfying the above is that when the Q value is 2000 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 porcelain composition of the present invention, as shown in FIG. 2, the main crystal phase is cordierite, and the other crystal phases are mullite, spinel, protoenstatite, clinoenstatite, and phorite. In some cases, stellite, cristobalite, tridymite, corundum, etc. are precipitated, but the precipitated phase differs depending on the composition.

In the dielectric porcelain composition of the present invention, a crystalline phase consisting of cordierite alone may be used.

As shown in FIG. 1, the dielectric resonator according to 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.

The dielectric porcelain of the present invention comprises,
For example, MgCO ₃ powder, Al ₂ O ₃ powder, and SiO ₂ powder are weighed at a predetermined ratio, wet-mixed and dried, and the mixture is dried at 1100 to 1300 ° C. in the atmosphere.
After calcining with, it was pulverized. An appropriate amount of a binder is added to the obtained powder to form a compact.
It is obtained by firing at 50 ° C. In particular, since dielectric porcelain having cordierite as a main crystal phase is difficult to sinter, it is necessary to find an appropriate firing temperature, and to fire at a strictly controlled firing temperature.

The dielectric porcelain composition of the present invention is composed of only Mg, Al, and Si as metal elements.
There are cases where r, Ni, Fe, Cr, Ca, P, Na, Ti, etc. are mixed. In this case, too, 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.

[0024]

EXAMPLE As raw material powder, 99% pure MgCO ₃ , 99.7% pure Al ₂ O ₃ , 99.4% pure SiO ₂
Using powders, these were weighed so that the sintered bodies had the composition shown in Table 1, wet-mixed for 15 hours, dried, calcined at 1200 ° C for 2 hours, and pulverized. An appropriate amount of a binder was added to the obtained powder and granulated.
It was molded under a pressure of 0 kg / cm ² to obtain a molded body having a diameter of 12 mm and a thickness of 8 mm. This molded body is placed in the atmosphere at 1300
The resultant was fired at 1450 ° C. for 2 hours to obtain a dielectric ceramic sample.

Using this sample, 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.

[0026]

[Table 1]

According to Table 1, the dielectric ceramic composition for high frequency according to the present invention has a low relative dielectric constant of 4 to 6 and a high Q value of 2000 or more at a measurement frequency of 10 GHz. Understand.

FIG. 2 shows an X-ray diffraction chart of Sample No. 5. From FIG. 2, it can be seen that, in addition to cordierite, protoenstatite and spinel are precipitated. FIG. 3 is a ternary diagram showing the composition range of the present invention and the composition of the sample.

[0029]

According to the dielectric ceramic composition for a high frequency wave of the present invention, a porcelain having a low relative dielectric constant of 4 to 6 and a high Q value of 2000 or more at 10 GHz can be obtained. By using the dielectric resonator as a support member or a substrate, a high-frequency circuit element such as a high-impedance microwave integrated circuit can be manufactured without deteriorating reliability. Also, because of its low dielectric constant and high Q value,
For example, microwaves, such as microwaves and millimeter-wave integrated circuits,
It is most suitable as a material for a circuit element substrate, a dielectric resonator support, a dielectric resonator, a dielectric waveguide, a dielectric antenna, etc. used in the millimeter wave band.

[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. 5 is an X-ray diffraction diagram showing the crystal structure of Sample No. 5. FIG.

FIG. 3 is a ternary composition diagram showing the composition range of the dielectric ceramic composition for high frequencies according to the present invention.

[Explanation of symbols]

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

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/00-35/22 C04B 35/42-35/49 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] A composite oxide comprising Mg, Al, and Si as metal elements, wherein the molar ratio composition formula of each metal element oxide is represented by xMgO-yAl ₂ O ₃ -zSiO ₂ , , Y, z satisfy 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100, have a relative permittivity of 6 or less, and a Q value of 2000 or more at a measurement frequency of 10 GHz. A dielectric ceramic composition for high frequency, comprising: 2. A dielectric resonator in which a dielectric ceramic 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.
Wherein the molar ratio composition formula of the oxide of each metal element is represented by xMgO—yAl ₂ O ₃ —zSiO ₂ , wherein x, y, and z are 10 ≦ x ≦ 40 10 ≦ y ≦ 40 20 ≦ z ≦ 80 x + y + z = 100, a dielectric resonator having a relative dielectric constant of 6 or less and a Q value at a measurement frequency of 10 GHz of 2,000 or more.