JPH11278927A - Dielectric porcelain composition, production of dielectric porcelain and dielectric resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dielectric porcelain composition, dielectric porcelain and dielectric resonator, having high εr and high Q value in high frequency region and making dispersion of εr, Q value and a temperature characteristic τf of resonance frequency small. SOLUTION: This dielectric porcelain composition contains at least rare earth element, Al, M (M: Sr or Sr and Ca) and Ti as metal elements and contains perovskite type crystalline phase represented by the compositional formula; aLn2 OX.bAl2 O3 .cMO.dBaO.eTiO2 (Ln: rare earth element) [0.056<=a<=0.450, 0.056<=b<=0.450, 100<=c<=0.500, 0<=d<=0.100, 0.100<e<0.470, 0.75<=b/a<=1.25, 0.75<=e/(c+d)<=1.25 and a+b+c+d+e=1] and comprising a solid solution of LnAIO( X+3)/2 (3<=x<=4) and MbaTiO3 as a main crystalline phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stably controls the relative dielectric constant .epsilon.r, the sharpness Q value of a resonator, and the temperature coefficient .tau.f in a high-frequency region such as a microwave and a millimeter wave, and suppresses variations in characteristics in manufacturing. The present invention relates to small dielectric ceramic compositions and dielectric resonators, for example, various resonator materials and MICs (Monolithic ICs) used in the high-frequency region.
The present invention relates to a dielectric ceramic composition used for a dielectric substrate material for use, a dielectric waveguide material, a multilayer ceramic capacitor, and the like, a method for manufacturing a dielectric ceramic, and a dielectric resonator.

[0002]

2. Description of the Related Art Dielectric ceramics are widely used in dielectric resonators, MIC dielectric substrates, waveguides, and the like in high-frequency regions such as microwaves and millimeter waves. The required characteristics are that (1) the relative permittivity is large for the demand for miniaturization because the wavelength of the electromagnetic wave propagating in the dielectric is reduced to 1 / εr ^1/2 , (2) That the dielectric loss in the high frequency region is small, that is, the Q value is high, and (3) the change of the resonance frequency with respect to temperature is small, that is, the temperature dependence of the relative permittivity εr is small and stable. There are mainly three characteristics.

[0003] To satisfy these requirements, the present applicant has
First, the relative dielectric constant of a composite oxide containing a rare earth element (Ln), Al, Ca and Ti is as high as 34 to 46,
A dielectric porcelain composition having a Q value of 20,000 or more has been proposed (see JP-A-6-76633).

[0004]

However, the above LnA
In the lCaTi-based dielectric porcelain composition, a high relative dielectric constant and a high Q
The dielectric constant ε in the manufacturing process
There has been a problem that values of r, Q value and temperature coefficient τf of resonance frequency fluctuate, and it is difficult to control these stably.

The present invention has been completed in view of the above circumstances, and has as its object a large relative permittivity εr, a high Q value, and a relative permittivity εr, a Q value and a temperature coefficient τf of resonance frequency. An object of the present invention is to provide a dielectric porcelain composition, a method of manufacturing a dielectric porcelain, and a dielectric resonator that can be controlled stably with small value variations.

[0006]

The dielectric ceramic composition of the present invention comprises at least a rare earth element (Ln) as a metal element,
It is composed of Al, Sr or a composite oxide containing Sr and Ca, and Ti, and has a composition formula of aLn ₂ O _x .bAl ₂ O ₃ .cMO.d
BaO.eTiO ₂ (where M is Sr or Sr
And Ca, 3 ≦ x ≦ 4), and a perovskite-type crystal phase as a main crystal phase.

[0007] In the above composition formula, a, b,
c, d and e are 0.056 ≦ a ≦ 0.450 0.056 ≦ b ≦ 0.450 0.100 ≦ c ≦ 0.500 0 ≦ d ≦ 0.100 0.100 <e <0.470 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / (c + d) ≦ 1.25 a + b + c + d + e = 1 is satisfied.

[0008] In the above dielectric porcelain composition,
In particular, it is composed of a composite oxide containing at least La, Al, Sr, and Ti as metal elements, and the composition formula based on the molar ratio is aLa ₂ O ₃ .bAl ₂ O ₃ .cSrO.eTiO.
₂ , a, b, c, e in the above composition formula
0.1061 ≦ a ≦ 0.2162 0.1050 ≦ b ≦ 0.2086 0.3040 ≦ c ≦ 0.4185 0.2747 ≦ e ≦ 0.4373 0.75 ≦ b / a ≦ 1.25 0 0.75 ≦ e / c ≦ 1.25 a + b + c + e = 1

In the above dielectric ceramic composition, it is desirable that the dielectric ceramic composition is composed of a single crystal phase of a perovskite crystal phase.
At least LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4) and RT
Desirably, it is formed of a solid solution with iO ₃ (R is an alkaline earth element containing at least Sr).

[0010] The method for manufacturing a dielectric porcelain of the present invention comprises:
A calcined powder having LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4) as a main crystal phase, and a calcined powder having RTiO ₃ (R is an alkaline earth element containing at least Sr) as a main crystal phase Are mixed, molded, and then fired.

Further, in the dielectric resonator according to the present invention, a dielectric porcelain is arranged between a pair of input / output terminals, wherein the dielectric porcelain operates by electromagnetic field coupling. It is composed of a body porcelain composition.

[0012]

According to the dielectric ceramic composition of the present invention, the relative dielectric constant εr is large, the Q value is high, and the relative dielectric constant εr, Q
And the temperature coefficient τf of the resonance frequency are small in variation, and a porcelain that can be controlled stably can be obtained. Further, as described above, at least L
According to the dielectric porcelain composition comprising a composite oxide containing a, Al, Sr and Ti, and having a solid solution of LaAlO ₃ and SrTiO ₃ as a main crystal phase, a higher Q value can be obtained.

A calcined powder having LnAlO _{(x + 3) / 2} (Ln: rare earth element, 3 ≦ x ≦ 4) as a main crystal phase;
promoting the simultaneous solid solution of the calcined powder by mixing and molding a calcined powder having iO ₃ (R is an alkaline earth element containing at least Sr) as a main crystal phase, followed by molding and firing. As a result, it is possible to obtain a dielectric ceramic substantially composed of a single crystal phase of a perovskite (ABO ₃ ) composite oxide crystal phase.

Further, according to the present invention, there is provided a dielectric resonator having a dielectric ceramic disposed between a pair of input / output terminals and operated by electromagnetic field coupling, wherein the dielectric ceramic is made of the dielectric ceramic composition. With this configuration, it is possible to provide a resonator having excellent stability of the no-load Q and the resonance frequency.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the dielectric ceramic composition of the present invention, it is important to control the main crystal phase in the dielectric ceramic composition in order to reduce the variation in dielectric characteristics. It is based on the viewpoint. The porcelain composition of the present invention may be a powder or a bulk body (porcelain) which is formed into a specific shape and then fired.

That is, the dielectric porcelain composition of the present invention comprises at least a rare earth element (Ln), Al, Sr or Sr
And a composite oxide containing Ca, Ti and a perovskite-type crystal phase as a main crystal phase.

The main crystal phase can be measured by analyzing the porcelain composition by X-ray diffraction. In the present invention, a perovskite-type crystal phase as a main crystal phase means that a main peak of a crystal phase composed of the solid solution by X-ray diffraction is higher than a main peak of another crystal phase,
In particular, it is desirable to consist essentially of only the perovskite-type crystal phase. In particular, this perovskite-type crystal phase has at least LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4).
And a solid solution of RTiO ₃ (R is an alkaline earth element containing at least Sr) (Ln, R) (Al, T)
i) Desirably, represented by O ₃ .

In the above dielectric ceramic composition, the composition formula based on the molar ratio of the metal element oxide is aLn ₂ O _x .bAl ₂ O ₃ .cMO.dBaO.eT
When represented by iO ₂ (M is Sr or Sr and Ca), the a, b, c, d, and e are 0.056 ≦ a ≦ 0.450 0.056 ≦ b ≦ 0.450. 100 ≦ c ≦ 0.500 0 ≦ d ≦ 0.100 0.100 <e <0.470 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / (c + d) ≦ 1.25 a + b + c + d + e = 1 It is important that

The reasons for limiting the amounts of the respective metal elements to the above ranges are as follows. That is, 0.056 ≦ a ≦ 0.45
The reason for setting the value to 0 is that when a <0.056, τf becomes positively large or the Q value decreases.
This is because in the case of 0.450, the relative dielectric constant εr decreases, the Q value decreases, and τf increases negatively. In particular, 0.078 ≦ a ≦ 0.325 is preferable.

The reason for 0.056 ≦ b ≦ 0.450 is that
This is because when b <0.056, the Q value decreases or τf increases positively, and when b> 0.450, the Q value decreases. In particular, 0.078 ≦ b ≦ 0.32
5 is preferred.

The reason for setting 0.100 ≦ c ≦ 0.500 is that
This is because when c <0.100, the Q value decreases or τf increases negatively, and when c> 0.500, τf increases positively or the Q value decreases. Because. In particular, it is preferable that 0.250 ≦ c ≦ 0.47.

The reason for 0 ≦ d ≦ 0.100 is that d> 0.
This is because if it is 100, the Q value decreases.

The reason for setting 0.100 <e <0.470 is that
When e ≦ 0.100, τf becomes negative and Q
This is because the value decreases, and when e ≧ 0.470, τf increases positively or the Q value decreases. In particular, it is preferable that 0.250 ≦ e ≦ 0.422.

0.75 ≦ b / a ≦ 1.25
This is because if b / a <0.75, the Q value decreases.
This is because if b / a> 1.25, the Q value decreases.
In particular, 0.80 ≦ b / a ≦ 1.20 is desirable.

The reason that 0.75 ≦ e / (c + d) ≦ 1.25 is satisfied is that if e / (c + d) <0.75, the Q value decreases, and e / (c + d)> 1. 25 is Q
This is because the value decreases. In particular, 0.80 ≦ e / (c +
d) ≦ 1.20 is desirable.

According to the present invention, in the above-mentioned dielectric porcelain composition, at least La, Al, Sr
And made from a composite oxide containing Ti, when expressed the composition formula by molar ratio _{aLa 2 O 3 · bAl 2 O} 3 · cSrO · eTiO 2, wherein a, b, c, e is, 0.1061 ≦ a ≦ 0.2162 0.1050 ≦ b ≦ 0.2086 0.3040 ≦ c ≦ 0.4185 0.2747 ≦ e ≦ 0.4373 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / c When satisfying ≦ 1.25 a + b + c + e = 1 and using a solid solution of LaAlO ₃ and SrTiO ₃ as a main crystal phase, a higher Q value can be achieved.

Thus, the dielectric porcelain composition of the present invention comprises:
The dielectric constant εr is large, the Q value is high, and the variation in the relative dielectric constant εr, the Q value, and the value of the temperature coefficient τf of the resonance frequency is small.

The method for producing the dielectric porcelain of the present invention includes:
A method in which oxide powders of a plurality of metal elements forming a dielectric porcelain are added and mixed at a predetermined ratio, then molded and fired (first manufacturing method), a plurality of metal elements forming a dielectric porcelain A method of temporarily calcining and pulverizing a mixture obtained by combining and mixing the oxide powders of the above, mixing them again, molding and calcining (a second production method).

According to the present invention, it is particularly desirable to employ the second manufacturing method in order to promote the solid solution of the metal oxide in the dielectric porcelain and to unite the crystal phase.

That is, Ln containing a rare earth element and Al
A calcined powder containing AlO _{(x + 3) / 2} (3 ≦ x ≦ 4) as a main crystal phase, and a calcined powder containing RTiO ₃ (R is an alkaline earth element containing at least Sr) as a main crystal phase. The powder is mixed, molded, and fired. That is, a calcined powder obtained by calcining and pulverizing a mixture of a rare earth element oxide and an Al oxide, and a calcining powder obtained by calcining and pulverizing a mixture of an alkaline earth metal oxide containing at least SrO and TiO ₂ Are mixed, molded into a predetermined shape, and then fired.

According to this manufacturing method, the above LnAl
A solid solution of O _{(x + 3) / 2} and RTiO ₃ (R is an alkaline earth element containing at least Sr), that is, (Ln,
It is possible to obtain a dielectric ceramic having a perovskite crystal represented by R) (Al, Ti) O ₃ as a main crystal phase and having small variations in the characteristic values of εr, Q value and τf. In addition,
Examples of the alkaline earth element include Ca and Ba in addition to Sr.

The reason why the variation in the characteristic values can be reduced by the manufacturing method of the present invention is considered as follows.

Generally, the raw material of the dielectric ceramic composition contains impurities, water and the like. Moreover, they elute as ions into the solvent during the manufacturing process, settle in the slurry,
For example, heavy elements are discharged during the spray drying, so that a composition change occurs. Therefore, it is difficult to accurately control the ratio of each component of Ln, Al, Sr, Ca, Ba, and Ti, even if the compounding is performed with high accuracy, thereby causing variation in characteristic values.

On the other hand, in the second production method, the ratio of each component can be controlled with high precision by mixing the calcined powder produced by the above combination, and as a result, the characteristic value It is presumed that the variation can be reduced.

More specifically, the second method for manufacturing a dielectric ceramic comprises the following steps (1) to (6).

(1) high-purity at least one rare earth element (Ln) oxide (Ln ₂ O ₃ ) as a starting material;
Each powder of aluminum oxide (Al ₂ O ₃ ) is used, and is mixed at a predetermined ratio, in particular, 0.75 ≦ Al ₂ O ₃ / Ln ₂ O
After weighing so that ₃ ≦ 1.25, pure water is added, and 1 to 10 until the average particle size of the mixed raw material becomes 2.0 μm or less.
For 0 hour, wet mixing and pulverization are performed by a ball mill using zirconia balls or the like.

(2) After drying this mixture,
After calcination at 300 ° C. for 1 to 10 hours, pulverized, LnAlO
_A calcined powder having _{(x + 3) / 2} (Ln: rare earth element, 3 ≦ x ≦ 4) as a main crystal phase is obtained.

(3) Similarly, a carbonate of an alkaline earth metal capable of forming an oxide (RO) of an alkaline earth (R) by heat treatment of calcium carbonate, strontium carbonate, barium carbonate or the like, and titanium oxide (TiO 2) ₂ ) Using each of the powders, a desired ratio as described above, in particular, 0.75
After weighing so that ≦ TiO ₂ /RO≦1.25, pure water is added, and wet mixing is performed by a ball mill using zirconia balls or the like for 1 to 100 hours until the average particle size of the mixed raw material becomes 2.0 μm or less. And crushing.

(4) After drying this mixture,
After calcining at 300 ° C. for 1 to 10 hours, pulverization is performed to obtain RTiO ₃
(R is an alkaline earth element containing at least Sr)
Is obtained as a main crystal phase.

(5) Next, the obtained LnAlO _{(x + 3) / 2}
And a calcined powder having RTiO ₃ as a main crystal phase are mixed at a predetermined ratio, and the mixed material is mixed for 1 to 100 hours until the average particle size becomes 2.0 μm or less, Wet mixing and grinding are performed by a ball mill using zirconia balls or the like.

(6) Further, after adding 3 to 10% by weight of an organic binder for molding, dehydration is performed, and then granulation or sizing is performed by a known method such as a spray drying method. The sized powder is formed into an arbitrary shape by a known method such as a mold pressing method, a cold isostatic pressing method, or an extrusion molding method.

(7) The molded body produced as described above is fired in the air at a temperature of 1400 to 1700 ° C. for 1 to 10 hours to obtain LnAlO _{(x + 3) / 2} , RTi
A dielectric porcelain having a solid solution with O ₃ (R is an alkaline earth element containing at least Sr) as a main crystal phase can be produced.

In particular, according to the above-mentioned second manufacturing method, the crystal phases are substantially LnAlO _{(x + 3) / 2} and RTiO ₃ (R
Is composed of a single phase of a perovskite-type crystal phase composed of (Ln, R) (Al, Ti) O ₃ composed of a solid solution with at least Sr-containing alkaline earth metal, so that a relative dielectric constant εr, A dielectric porcelain excellent in stability of Q value and τf can be manufactured.

In the present invention, rare earth elements (Ln) used include Y, La, Ce, Pr, Sm, and E.
u, Gd, Dy, Er, Yb, Nd and the like. The form of these rare earth element (Ln) oxides is Ln ₂ O
_x (3 ≦ x ≦ 4). As the rare earth elements, Y, La, Sm, Gd, Dy, Er, Y
b and Nd are preferable, and La and Nd are particularly preferable.

Further, according to the dielectric porcelain composition of the present invention, the above-mentioned dielectric porcelain composition is used as a main component, and
nO, NiO, SnO ₂ , Co ₃ O ₄ , ZrO ₂ , WO
₃ , LiCO ₃ , Rb ₂ CO ₃ , Sc ₂ O ₃ , V
₂ O ₅ , CuO, SiO ₂ , MgCO ₃ , Cr ₂ O ₃ ,
B ₂ O ₃ , GeO ₂ , Sb ₂ O ₅ , Nb ₂ O ₅ , Ta ₂
O ₅ or the like may be added. These can be added in a proportion of 6 parts by weight or less based on 100 parts by weight of the main component, depending on the added components.

The dielectric porcelain composition of the present invention is most preferably used as a dielectric porcelain of a dielectric resonator. FIG. 1 shows a schematic diagram of a TE mode type dielectric resonator. The dielectric resonator shown in FIG. 1 is provided with an input terminal 2 and an output terminal 3 on opposite sides of an inner wall of a metal case 1, and a dielectric ceramic made of the above-described dielectric ceramic composition is provided between the input / output terminals 2 and 3. 4 are arranged. In such a TE mode type dielectric resonator, a microwave is input from the input terminal 2, and the microwave is confined in the dielectric porcelain 4 by reflection at a boundary between the dielectric porcelain 4 and free space, and a specific frequency Causes resonance. This signal is electromagnetically coupled to the output terminal 3 and output.

Although not shown, the dielectric porcelain composition of the present invention is applied to a coaxial resonator, a strip line resonator, a TM mode dielectric porcelain resonator using a TEM mode, and other resonators. Needless to say, Furthermore,
Even if the input terminal 2 and the output terminal 3 are provided directly on the dielectric ceramic 4, a dielectric resonator can be formed.

The above-mentioned dielectric porcelain 4 is a resonance medium having a predetermined shape made of the dielectric porcelain composition of the present invention, and has a rectangular parallelepiped, cubic, plate-like, disk, cylindrical, polygonal, or other resonance medium. Any three-dimensional shape is possible. The frequency of the input high-frequency signal is about 100 MHz to 300 GHz, and the resonance frequency is 200 MHz to 100 GHz.
Hz is practically preferable.

Thus, the dielectric resonator of the present invention can improve the no-load Q, the stability of the resonance frequency, and the temperature stability of the resonance frequency by using the above-mentioned dielectric ceramic composition.

It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the scope of the present invention.

[0051]

EXAMPLES (Example 1) Based on the above-described second manufacturing method, a dielectric ceramic was manufactured through the following steps (1) to (7).

(1) As a starting material, a rare earth element (Ln) oxide Ln ₂ O _x (3 ≦ x ≦ 4) having a purity of 99% or more, specifically, Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Pr
₆ O ₁₁ , Sm ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Dy ₂
O ₃ , Er ₂ O ₃ , Yb ₂ O ₃ , Nd ₂ O ₃ powders and aluminum oxide (Al ₂ O ₃ ) powders were weighed so as to have the molar ratio shown in Table 1. , Pure water and mixed, and wet-mixed with a ball mill for about 20 hours until the average particle size of the mixed raw material becomes 2.0 μm or less,
Grinding was performed.

(2) The mixture was dried, calcined at 1200 ° C. for 2 hours, and pulverized to an average particle size of 0.4 to 1.5 μm.
Thus, calcined powder A having m as main crystal phase of LnAlO _{(x + 3) / 2} (3 ≦ x ≦ 4) was obtained.

(3) Similarly, calcium carbonate (CaCO
₃ ) Powders of strontium carbonate (SrCO ₃ ), barium carbonate (BaCO ₃ ), and titanium oxide (TiO ₂ ) were weighed so as to have the molar ratio shown in Table 1, and pure water was added and mixed. The average particle size of the mixed raw material is 2.
The mixture was wet-mixed with a ball mill for about 20 hours until it became 0 μm or less, and pulverized.

(4) The mixture was dried, calcined at 1200 ° C. for 2 hours, and pulverized to an average particle size of 2.5 to 10 μm.
(The R, at least an alkaline earth element containing Sr) of RTiO ₃ to give the calcined powder B to the main crystal phase.

(5) The calcined powder A of the above (2) and the calcined powder B of the above (4) are mixed with pure water by adding pure water, and the mixture is adjusted to have an average particle size of 2.0 μm or less. Until the mixture was wet-mixed for about 20 hours by a ball mill and pulverized.

(6) 5% by weight of the obtained slurry
Was added and the particles were sized by spray drying.

(7) The obtained sized powder is reduced to about 1 ton / c
It was molded into a disk at a pressure of m ² and fired in the air at a temperature of 1400 to 1700 ° C. for 2 hours to produce a dielectric ceramic. An X-ray diffraction measurement was performed on the obtained porcelain. As a result, each of the porcelains had a perovskite-type crystal phase composed of a solid solution of LnAlO _{(x + 3) / 2} and RTiO ₃ as a main crystal phase.

Then, the disk portion (main surface) of the obtained porcelain is polished flat, and ultrasonically cleaned in acetone.
After drying for a time, the measurement frequency is 3.5 by the cylindrical resonator method.
The relative dielectric constant εr, the Q value, and the temperature coefficient τf of the resonance frequency were measured at 30 to 4.5 GHz, and the average value was calculated. The Q value is generally established in a microwave dielectric (Q value)
From the relationship of × (measurement frequency f) = (constant), it was converted to a Q value at 1 GHz. The temperature coefficient τf of the resonance frequency is −4
It measured in the range of 0-85 degreeC.

The same experiment as above was performed 30 times using the same starting materials as above, and the relative dielectric constant of 30 lots was determined using the average value of the relative dielectric constant εr, Q value, and the temperature coefficient τf of the resonance frequency of each lot. The standard deviation σ of each of εr, Q value, and temperature coefficient τf of the resonance frequency is expressed as σ = ｛Σ (wy) ² / (n−
1) Calculated by｝ ^1/2 .

Here, w is ε of 30 samples of each lot.
The average value of r, the average value of Qf, or the average value of τf, y
Is the value obtained by dividing the total value of the average value of εr of each lot by 30, or the value obtained by dividing the total value of the average value of Qf of each lot by 30 or the value obtained by dividing the total value of the average value of τf of each lot by 30 And n = 30. The results are shown in Tables 1 to 3.

On the other hand, as a comparative example, the rare earth element oxide L
n ₂ O _x (3 ≦ x ≦ 4), aluminum oxide (Al ₂ O
₃ ), powders of calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), barium carbonate (BaCO ₃ ) and titanium oxide (TiO ₂ ) are simultaneously mixed and pulverized.
A dielectric porcelain was prepared by drying, calcining, sizing, firing and polishing, and the same test was performed on the obtained dielectric porcelain. The results were as follows: Sample Nos. 40 to 55 in Table 2, Sample N in Table 3
o.83-87.

[0063]

[Table 1]

[0064]

[Table 2]

[0065]

[Table 3]

Further, changes in X-ray diffraction measurement during the above manufacturing process were examined, and as an example, FIGS. First, X-ray diffraction charts of calcined powder A and calcined powder B produced by calcining are shown in FIGS. As is clear from FIG. 2, the calcined powder A was La
It is a powder having AlO ₃ as the main crystal phase. As is clear from FIG. 3, it is understood that the calcined powder B is a powder having SrTiO ₃ as the main crystal phase.

Next, FIGS. 4 and 5 show X-ray diffraction charts of the mixed powder obtained by mixing the calcined powder A and the calcined powder B with the compositions of Samples No. 1 and No. 10, respectively. 6 and 7 show X-ray diffraction charts of the dielectric porcelain after firing using the mixed powder. As is clear from the results of FIGS. 6 and 7, a peak due to a solid solution of LaAlO ₃ and SrTiO ₃ is detected in the middle of each peak position, and the perovskite type of (La, Sr) (Al, Ti) O ₃ is detected. It turns out that it consists of a single crystal phase due to the crystal phase.

As is evident from the results of Tables 1 to 3, the composition ratio of each component is within the range of the present invention (Nos. 1 to 28).
Means that the relative dielectric constant εr is 30 or more, the Q value when converted to 1 GHz is 20,000 or more, τf is within ± 30 (ppm / ° C.), and the standard deviations of εr, Qf and the temperature coefficient τf of the resonance frequency are 0, respectively. 0.3 or less, 3000 or less, 0.7p
Excellent dielectric properties within pm / ° C were obtained.

On the other hand, dielectric ceramic compositions outside the composition range of the present invention (Nos. 29 to 39 and 76 to 82) have a low εr or a low Q value, or an absolute value of τf exceeding 30. Was.

Nos. 40 to 55, 83 mixed simultaneously
~ 87, the average values of εr, Q value and τf were equivalent to those of the present invention, but the standard deviation σ of εr was 1 or more, and τf
Has a large variation with a standard deviation σ of 2 ppm / ° C. or more,
In some comparative examples, the standard deviation σ of Qf exceeded 3000, and the dispersion was large.

In particular, among the products of the present invention, 0.1061 ≦
a ≦ 0.2162, 0.1050 ≦ b ≦ 0.2086,
0.3040 ≦ c ≦ 0.4185, 0.2747 ≦ e ≦
0.4373, 0.75 ≦ b / a ≦ 1.25, 0.75
≤e / c≤1.25 sample Nos. 56 to 75 are 1 GHz
Excellent dielectric properties having a Qf value of 40,000 or more when converted to were obtained.

(Example 2) The calcined powders of the porcelain compositions shown in Tables 1 and 2 of Example 1 were mixed at the weight ratio shown in Table 4, and then molded, fired and polished in the same manner as in Example 1. The dielectric properties of 30 samples were measured, and the experiment was performed 30 times in the same manner as in Example 1 to calculate the standard deviation σ of the dielectric properties.

[0073]

[Table 4]

As a result, in all of the samples Nos. 88 to 99, the relative dielectric constant εr was 30 or more, and the Q value when converted to 1 GHz was 20,000 or more.
The standard deviation σ of εr, Qf, and τf was within 0.2, within 1,000, and within 0.2 ppm / ° C., respectively.
It was possible to further reduce the variation.

Further, when the X-ray diffraction measurement was performed on the obtained dielectric porcelain, it was found that each of them consisted of a single crystal phase of a perovskite type crystal phase.

[0076]

As described above in detail, according to the present invention, at least a rare earth element, Al, M (M: S
r alone or Sr and Ca) and a perovskite-type crystal phase containing Ti in a specific range as a main crystal phase, a high relative permittivity εr and a high Q value can be obtained in a high frequency region, and Variations in εr, Q value, and τf can be reduced. As a result, it can be applied to resonator materials, MIC dielectric substrate materials, dielectric waveguides, dielectric antennas, and other various electronic components used in microwave and millimeter wave regions. When used as a resonator, the stability of the no-load Q and the resonance frequency can be improved, and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a dielectric resonator of the present invention.

FIG. 2 is an X-ray diffraction chart of LaAlO ₃ calcined powder in an example of the present invention.

FIG. 3 is an X-ray diffraction chart of SrTiO ₃ calcined powder in an example of the present invention.

FIG. 4 shows LaA in an example (sample No. 1) of the present invention.
4 is an X-ray diffraction chart of a mixed powder of a lO ₃ calcined powder and a SrTiO ₃ calcined powder.

FIG. 5 shows La in an example of the present invention (sample No. 10).
4 is an X-ray diffraction chart of a mixed powder of AlO ₃ calcined powder and SrTiO ₃ calcined powder.

FIG. 6 is an X-ray diffraction chart of a dielectric porcelain in an example (sample No. 1) of the present invention.

FIG. 7 is an X-ray diffraction chart of a dielectric porcelain in an example (sample No. 10) of the present invention.

[Explanation of symbols]

 1: Metal case 2: Input terminal 3: Output terminal 4: Dielectric porcelain

Claims (6)

[Claims] (1) at least a rare earth element (L) as a metal element;
n), composed of Al, Sr or a composite oxide containing Sr and Ca, and Ti, wherein the composition formula based on the molar ratio of the metal element is aLn ₂ O _x .b Al ₂ O ₃ .cMO.dBaO.eT
iO ₂ (where M is Sr or Sr and Ca, 3 ≦ x ≦
When represented by 4), the a, b, c, d, and e are 0.056 ≦ a ≦ 0.450 0.056 ≦ b ≦ 0.450 0.100 ≦ c ≦ 0.500 0 ≦ d ≦ 0.100 0.100 <e <0.470 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / (c + d) ≦ 1.25 a + b + c + d + e = 1 and a perovskite type crystal phase is mainly used. A dielectric porcelain composition having a crystalline phase. 2. The dielectric porcelain composition according to claim 1, wherein the dielectric porcelain composition comprises substantially only a perovskite-type crystal phase. 3. The method according to claim 1, wherein the perovskite crystal phase comprises at least LnAlO.sub. _{(X + 3) / 2} (3.ltoreq.x.ltoreq.4) and RTiO.
_3. The dielectric ceramic composition according to claim 1, comprising a solid solution with ₃ (R is an alkaline earth element containing at least Sr). 4. At least La, Al, S as a metal element
made of a complex oxide containing r and Ti, when represented the formula by molar ratio _{aLa 2 O 3 · bAl 2 O} 3 · cSrO · eTiO 2, wherein a, b, c, e is 0.1061 ≦ a ≦ 0.2162 0.1050 ≦ b ≦ 0.2086 0.3040 ≦ c ≦ 0.4185 0.2747 ≦ e ≦ 0.4373 0.75 ≦ b / a ≦ 1.25 0.75 ≦ e / 2. The dielectric ceramic composition according to claim 1, wherein c ≦ 1.25 a + b + c + e = 1 is satisfied. 5. LnAlO _{(x + 3) / 2} (Ln: rare earth element,
The calcined powder to a 3 ≦ x ≦ 4) as a main crystalline phase, RTiO ₃
(R is an alkaline earth element containing at least Sr) mixed with a calcined powder having a main crystal phase, molded, and then fired. 6. A dielectric resonator having a dielectric resonator arranged between a pair of input / output terminals and operated by electromagnetic field coupling, wherein the dielectric ceramic is any one of claims 1 to 4. A dielectric resonator comprising the dielectric ceramic composition of the above.