JP3523474B2 - High frequency dielectric ceramic composition, dielectric resonator, and dielectric waveguide - 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 porcelain composition used in high frequencies such as microwaves and millimeter waves. A high frequency dielectric porcelain composition useful as a material for circuit element substrates, dielectric resonators, dielectric resonator support members, dielectric waveguides, dielectric antennas, etc. used in a band, and a support member on a substrate. The present invention relates to a dielectric resonator in which a dielectric ceramic is fixed via a dielectric resonator, and a dielectric waveguide in which the dielectric ceramic is interposed between a pair of parallel plate conductors.

[0002]

2. Description of the Related Art A high-frequency circuit element such as a microwave or millimeter-wave integrated circuit may employ a structure in which a dielectric ceramic is fixed to a substrate via a supporting member. For example, as shown in FIG. 1, the dielectric resonator control type microwave oscillator mounts the dielectric porcelain 1 on the porcelain substrate 3 via the support member 2, and the electromagnetic field H leaking to the outside of the dielectric porcelain 1 is obtained.
Is used to connect to the strip line 4 provided on the porcelain substrate 3, and these are housed in the metal case 5.

In this type of high-frequency circuit element, by controlling the electric field of the dielectric porcelain 1 leaking through the support member 2, a resonance system with a high unloaded Q is constructed. It is necessary to use a material having a low relative permittivity and a low dielectric loss (tan δ) (high Q value) for the support member 2. For this reason, conventionally, forsterite having a relative permittivity of about 7 and a Q value of about 15,000 at a measurement frequency of 10 GHz has been conventionally used as the material of the supporting member 2, and the material of the porcelain substrate 3 mainly has the relative permittivity. Alumina porcelain having a Q value of about 20,000 at a measurement frequency of 10 GHz was adopted (for example, Japanese Patent Laid-Open No. 62-103).
904, etc.).

On the other hand, as a material having a low relative dielectric constant, conventionally, a Q value at a relative dielectric constant of 4 to 6 and 10 GHz is 1000.
A glass ceramic of a certain degree is used (see, for example, JP-A-63-89454).

[0005]

However, the relative permittivities of conventionally used alumina and forsterite are about 10 and about 7, respectively, and with the recent widespread use of high frequency dielectric resonators. , Lower dielectric constant materials have been sought.

On the other hand, porcelain such as glass ceramics used as a low dielectric constant material has a small relative dielectric constant of about 4 to 6, but has a Q value of about 1000 at 10 GHz. Along with the widespread use of resonators, a low dielectric constant material having a higher Q value has been required.

Alumina porcelain, which is mainly used for the porcelain substrate of the resonator, has a relatively high relative permittivity of about 10, and the line width becomes too small when forming a high impedance stripline (usually (1 μm or less), there is a problem that disconnection occurs or relative line width variation increases, 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 thickness of the substrate is constant, so instead of reducing the line width, the relative permittivity is reduced. Impedance can also be increased by using a substrate material having a low dielectric constant, and thus a lower dielectric constant material has been required.

It is an object of the present invention to provide a high frequency dielectric ceramic composition, a dielectric resonator and a dielectric waveguide which have a low dielectric constant and a high Q value at a measurement frequency of 10 GHz.

[0009]

The high frequency dielectric ceramic composition of the present invention is a composite oxide composed of B and Si as metal elements, and the weight ratio composition formula of the oxide of each metal element is xB _2. When expressed as O ₃ · ySiO ₂ , the above x and y are 0.1 ≦ x ≦ 20, 80 ≦ y ≦ 99.9, and x + y = 10.
And a main component satisfying 0, and 0.1 to 10 parts by weight in terms of oxide of at least one of Group 4a elements of the periodic table based on 100 parts by weight of the main component. here,
Relative permittivity is 4 or less and Q value at 10 GHz is 20
It is preferably 00 or more.

Further, the dielectric resonator of the present invention is a dielectric resonator in which a dielectric ceramic is fixed on a substrate through a supporting member, wherein the substrate and / or the supporting member is the high frequency dielectric. It is composed of a porcelain composition.

Further, the dielectric waveguide of the present invention is a dielectric waveguide in which a dielectric ceramic is interposed between a pair of parallel plate conductors, wherein the dielectric ceramic is the high frequency dielectric ceramic composition. It consists of

[0012]

In the high frequency dielectric ceramic composition of the present invention, B,
For complex oxides of specific composition made of Si, Ti, Z
By containing a predetermined amount of at least one group 4a element of the periodic table consisting of r and Hf, the dielectric constant is 4 or less, 10
It is possible to obtain a low dielectric constant and a high Q value having a Q value of 2000 or more at GHz. In particular, the Q value can be improved by containing a predetermined amount of at least one element of Group 4a of the periodic table.

By using such a high frequency dielectric ceramic composition as a support member or a substrate of a dielectric resonator, for example, a high frequency circuit element such as a high impedance microwave integrated circuit can be made reliable. Can be manufactured without damaging. Furthermore, by using the dielectric ceramics interposed between a pair of parallel plate conductors, it is possible to manufacture a high-precision dielectric line with less transmission loss, at low cost.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The high frequency dielectric ceramic composition of the present invention is a composite oxide composed of B and Si as metal elements, and the weight ratio composition formula of the oxide of each metal element is xB ₂
When expressed as O ₃ · ySiO ₂ , the above x and y are 0.1 ≦ x
The main components are those satisfying ≦ 20, 80 ≦ y ≦ 99.9, and x + y = 100.

The main component composition of the high frequency dielectric ceramic composition of the present invention is limited to the above range for the following reason. That is, the weight percentage x of B ₂ O ₃ is 0.1 ≦ x ≦ 20 (80
≦ y ≦ 99.9) means that when x is smaller than 0.1% by weight (y is larger than 99.9% by weight), the sintered body is not densified, and 20% by weight is set. When it exceeds (y is 80
This is because a good sintered body cannot be obtained and the Q value becomes low (when it is less than wt%). In particular, x showing the amount of B ₂ O ₃ is Q
From the point that the value is 4000 or more, 0.2 ≦ x ≦ 10 (90
≦ y ≦ 99.8) is desirable.

In the present invention, 0.1 to 10 parts by weight in terms of oxide of at least one element of Group 4a of the periodic table is further contained with respect to 100 parts by weight of the above main component. In the range of 0.1 to 10 parts by weight in terms of oxide, at least one of Group 4a elements of the periodic table was further added to 100 parts by weight of the main component. Because. On the other hand, if the amount is less than 0.1 parts by weight, the effect of addition is small, and
This is because the relative dielectric constant becomes larger than 4 when the amount is more than the weight part. As elements of Group 4a of the periodic table, Ti, Z
Among them, there are r and Hf, but among them, Ti is preferable from the viewpoint that the raw material is inexpensive and the Q value is high.

Q value at a measuring 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 a recent high frequency band dielectric resonator. The higher the Q value, the more desirable, but especially the measurement frequency is 10 GHz.
It is desirable that the Q value at is 3000 or more.

The high frequency dielectric porcelain composition of the present invention comprises, for example, B ₂ O ₃ powder, SiO ₂ powder, and
Using TiO ₂ powder, ZrO ₂ powder, and HfO ₂ powder, weighed at a predetermined ratio, wet-mixed and dried, the powder thus obtained was added with an appropriate amount of a binder, and the powder was molded in the atmosphere at 1250 to 1250. It is obtained by firing at 1400 ° C.

Further, in the high frequency dielectric ceramic composition of the present invention, the main phase is a glass phase, and other crystal phases are cristobalite, tridymite, quartz, Ti, Zr,
Oxides of Hf elements may precipitate, but the precipitation phase differs depending on the composition.

Further, the dielectric resonator of the present invention, as shown in FIG. 1, has a dielectric ceramic 1 on a substrate 3 with a supporting member 2 interposed therebetween.
The support member 2 or the substrate 3, or the support member 2 and the substrate 3 are made of the above-mentioned high frequency dielectric ceramic composition.

Further, as shown in FIG. 2, the dielectric waveguide of the present invention has a dielectric ceramic 12 interposed between a pair of parallel plate conductors 11. It is composed of a dielectric ceramic composition.

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 resonator dielectric ceramic, or a dielectric waveguide. , Any dielectric antenna, etc. can be applied, but as described above, a dielectric waveguide formed by holding a dielectric ceramic on a supporting member or substrate of a dielectric resonator or between parallel plate conductors. It is also optimal as the dielectric porcelain of the tube.

Further, the dielectric ceramic composition of the present invention is most suitable as the substrate 13 of the dielectric antenna in which the conductors 14 are formed on the upper and lower surfaces of the substrate 13 as shown in FIG.

The high frequency dielectric ceramic composition of the present invention contains B, Si and Ti, Zr and Hf as metal elements.
Although it contains an element, for example, Al, Ba, Ni, Fe, Cr, as impurities in the pulverized balls or the raw material powder,
Ca, P, Na, etc. may be mixed in, but in this case as well, a porcelain having a low dielectric constant and a high Q value can be obtained as long as the above composition is satisfied.

[0025]

Using a purity of 95% B ₂ O _3, 99% of the SiO ₂ powder, purity of 99% or more of the TiO ₂ powder, ZrO ₂ powder, the HfO ₂ powder as EXAMPLES material powder, these sintered body Table 1 was weighed so as to have the composition shown in FIG. 1, wet-mixed for 15 hours, then dried, and an appropriate amount of binder was added to the obtained powder to granulate it, which was molded under a pressure of 1000 kg / cm ^2. A molded body having a diameter of 12 mm and a thickness of 8 mm was obtained. The molded body was fired at the temperature shown in Table 1 for 2 hours to obtain a dielectric ceramic sample.

Using this sample, the dielectric constant and the Q value were measured by the dielectric cylinder resonator method at a measurement frequency of 20 GHz. Regarding the Q value, assuming that Qf = constant, 10 GH
The Q value at z was determined. The results are shown in Table 1.

[0027]

[Table 1]

From Table 1, it is understood that the sample of the present invention has a relative dielectric constant of 4 or less and a Q value of 2000 or more at 10 GHz. Further, it is understood that the Q value is improved by containing a predetermined amount of Ti, Zr, and Hf element oxides. FIG. 4 shows the relationship between the addition amount of the Group 4a element oxide of the periodic table, the relative dielectric constant, and the Q value. In the above composition formula,
1375 with the composition of the comparative example in which x is 5.0 and y is 95.0
The product fired at ° C had a relative dielectric constant of 3.7 and a Q value of 5200 at 10 GHz. This composition is also shown in FIG.
Plotted on.

An X-ray diffraction chart of Sample No. 14 is shown in FIG. It can be seen from FIG. 5 that cristobalite and TiO ₂ are precipitated in addition to the glass phase.

[0030]

INDUSTRIAL APPLICABILITY With the high frequency dielectric ceramic composition of the present invention, a porcelain having a low relative dielectric constant of 4 or less and a high Q value of 2000 or more at 10 GHz can be obtained. By using the support member or the substrate of the body resonator, a high-impedance circuit element for high frequency such as a microwave integrated circuit can be manufactured without impairing reliability. Also, because of the 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 circuit element substrates, dielectric resonator support members, dielectric resonators, dielectric waveguides, dielectric antennas, etc. used in the millimeter wave band.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a dielectric waveguide of the present invention.

FIG. 3 is a perspective view showing a dielectric antenna.

FIG. 4 is a graph showing a relationship between an additive amount, a dielectric constant, and a Q value.

FIG. 5 is an X-ray diffraction chart of Sample No. 14.

[Explanation of symbols]

1. Dielectric porcelain 2 ... Support member 3 ... Porcelain substrate 4 ... strip line 5: Metal case 11-parallel plate conductor 12 ... Dielectric porcelain 13 ... Substrate 14 ... conductor

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Claims (4)

(57) [Claims] 1. A composite oxide comprising B and Si as a metal element, wherein the weight ratio composition formula of each metal element oxide is x.
When expressed as B ₂ O ₃ · ySiO ₂ , x and y are 0.1
≦ x ≦ 20, 80 ≦ y ≦ 99.9, x + y = 100, and 100 parts by weight of the main component, at least one of Group 4a elements of the periodic table is 0 in terms of oxide. 1-10 weight part is contained, The dielectric ceramic composition for high frequencies characterized by the above-mentioned. 2. A dielectric constant of 4 or less and a Q value at 10 GHz of 2000 or more.
The high frequency dielectric porcelain composition described. 3. A high frequency dielectric ceramic composition according to claim 1, wherein the substrate and / or the supporting member is a dielectric resonator formed by fixing a dielectric ceramic on a substrate via a supporting member. A dielectric resonator comprising: 4. A dielectric waveguide comprising a pair of parallel plate conductors and a dielectric ceramic interposed therebetween, wherein the dielectric ceramic comprises the high frequency dielectric ceramic composition according to claim 1. A dielectric waveguide characterized by: