JP2002187771A - Dielectric porcelain and dielectric resonator using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain dielectric porcelain having high εr and high Q value in a high frequency region and a small absolute value of the temperature coefficient τf of the resonance frequency. SOLUTION: The porcelain contains each specified range of La2O3, Al2O3, SrO and TiO2 and satisfies 0.10<=B/A<=0.60, wherein A is the X-ray diffraction peak intensity attributed to the (110) plane of a perovskite-type crystal consisting of a solid solution of LaAlO3 and SrTiO3, and B is the X-ray diffraction peak intensity attributed to the (105) plane of Sr3Ti2O7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic having a high Q value in a high frequency range such as a microwave and a millimeter wave, and is used in a high frequency range such as a microwave and a millimeter wave. The present invention relates to a dielectric ceramic which can be used for various resonator materials, a dielectric substrate material for an MIC (Monolithic IC), a dielectric waveguide material, a multilayer ceramic capacitor, and the like, and a dielectric resonator using the same.

[0002]

2. Description of the Related Art Hitherto, dielectric ceramics have been widely used in dielectric resonators, MIC dielectric substrates, waveguides, and the like in high-frequency regions such as microwaves and millimeter waves.

[0003] Dielectric ceramics are widely used in dielectric resonators, dielectric substrates for MICs, waveguides, and the like in high-frequency regions such as microwaves and millimeter waves. As the required characteristics, (1) When the relative dielectric constant is εr, the wavelength is reduced to 1 / εr ^1/2 in the dielectric, so that the relative dielectric constant is large for the demand for miniaturization, (2) Dielectric loss at high frequency is small, that is, a high Q value, and (3) Change in resonance frequency with respect to temperature is small and stable, that is, temperature coefficient τ _{f of} resonance frequency is small. There are three main characteristics.

Conventionally, as the dielectric porcelain, the present applicant has disclosed, for example, a rare earth element-Al-Sr-Ca-Ba- as disclosed in JP-A-11-278927.
Ti-based dielectric porcelain and JP-A-2000-20393
La-Al-Sr-T as disclosed in JP-A-4
An i-Mn based dielectric porcelain has been proposed. In such a dielectric ceramic, εr is 30 to 46, and the product Q of the Q value and the frequency f is Q
f can be controlled in the range of 20,000 to 85000 GHz, and the temperature coefficient τ _f of the resonance frequency can be controlled in the range of −30 to +30 ppm / ° C.

[0005] Japanese Patent Application Laid-Open No. 2-192460 discloses Ti
A dielectric porcelain comprising O ₂ —ZrO ₂ —SnO ₂ as a main component and CoO and Nb ₂ O ₅ added thereto is disclosed.

[0006]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open Nos. 11-278927 and 2000-2
In the dielectric porcelain disclosed in Japanese Patent No. 03934,
When r is in the range of 24-36, Qf may be 7
Lower than 0000 GHz or the absolute value of τ _f is 30
There was a problem that it became larger than ppm / ° C.

In a TiO ₂ -ZrO ₂ -SnO ₂ dielectric ceramic, Qf can be improved by adding an additive such as CoO or Nb ₂ O ₅ as disclosed in Japanese Patent Application Laid-Open No. 2-192460. The problem is that the addition of additives increases the cost of raw materials, increases the cost of the production process, complicates the production process, and necessitates the control of the firing atmosphere. was there.

The present invention has been completed in view of the above circumstances.
f is 70,000 GHz or more and the temperature coefficient τ of the resonance frequency
An object of the present invention is to provide a dielectric porcelain and a dielectric resonator having an absolute value of _f of 30 ppm / ° C. or less.

[0009]

Means for Solving the Problems The present inventor has studied the above problems, and as a result, it has been found that the present invention comprises a composite oxide containing at least La, Al, Sr and Ti as metal elements. By controlling the molar ratio of the oxide and the X-ray diffraction peak intensity ratio, the Qf is 700 when the relative dielectric constant εr is in the range of 24-36.
It was found that a dielectric ceramic having an absolute value of the temperature coefficient τ _f of the resonance frequency of 30 ppm / ° C. or less can be obtained at 00 GHz or more.

That is, the dielectric porcelain of the present invention is composed of oxides containing at least La, Al, Sr and Ti as metal elements, and the composition formula based on the molar ratio of these metal oxides is aLa ₂ O ₃ .bAl When a, b, c, and d are expressed as ₂ O ₃ .cSrO.dTiO ₂ , 0.056 ≦ a ≦ 0.214 0.056 ≦ b ≦ 0.214 0.300 ≦ c ≦ 0.540. 220 ≦ d ≦ 0.470 a + b + c + d = 1, and the perovskite-type crystal composed of a solid solution of LaAlO ₃ and SrTiO ₃ has a (110) plane assigned X-ray diffraction peak intensity of A and Sr ₃ Ti ₂ O ₇ of ( 105) When the X-ray diffraction peak intensity assigned to the plane is B, 0.10 ≦ B / A
≦ 0.60.

Still further, the dielectric porcelain of the present invention may be Sr ₂
X-ray diffraction peak intensity attributable to the (101) plane of TiO ₄ is C,
The X-ray diffraction peak intensity assigned to the (110) plane of SrLaAlO ₄ is D, the X-ray diffraction peak intensity assigned to the (440) plane of Sr ₃ Al ₂ O ₆ is E, and the X-ray diffraction assigned to the (−211) plane of SrAl ₂ O _4. Assuming that the peak intensity is F, 0 ≦ C / A ≦ 0.1
0, 0 ≦ D / A ≦ 0.40, 0 ≦ E / A ≦ 0.20, 0
It is characterized by satisfying at least one of ≦ F / A ≦ 0.20.

Further, the dielectric porcelain of the present invention further comprises Sn
Is contained in an amount of 8.0 parts by weight or less in terms of SnO ₂ .

Further, the dielectric porcelain of the present invention is characterized in that at least a part of the Sn is dissolved in a Ti site of a crystal phase containing Ti.

Further, the dielectric porcelain of the present invention comprises Mn, W,
At least one of Ta and Nb is MnO ₂ ,
WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ are contained in a total of 3.0 parts by weight or less in terms of Nb ₂ O ₅ .

Still further, the present invention is characterized in that the above-mentioned dielectric ceramic is arranged between a pair of input / output terminals to form a dielectric resonator.

[0016]

According to the dielectric porcelain of the present invention, the dielectric porcelain is composed of an oxide containing at least La, Al, Sr and Ti as metal elements, and the composition by the molar ratio of these metal oxides satisfies the above range, When the X-ray diffraction peak intensity ratio satisfies the above range, the relative dielectric constant εr is 24 to 36.
, The absolute value of the temperature coefficient τ _f of the resonance frequency can be controlled to be 30 ppm / ° C. or less.

According to the dielectric porcelain of the present invention, Sn
Of 8.0 parts by weight or less in terms of SnO ₂ ,
It can be further reduced control the absolute value of tau _f in the range of Ipushiron'aru24～36.

Further, according to the dielectric porcelain of the present invention, S
Since at least a part of n is dissolved in the Ti site of the crystal phase containing Ti, the absolute value of τ _f can be controlled further smaller.

Further, at least one of Mn, W, Ta, and Nb is replaced with MnO ₂ , WO ₃ , Ta ₂ O ₅ , N
By containing a total of 3.0 parts by weight or less in terms of b ₂ O ₅ , Qf can be maintained at a higher value.

Further, when the dielectric ceramic of the present invention is arranged between a pair of input / output terminals to form a dielectric resonator, a change in resonance frequency due to a temperature change of the dielectric resonator can be reduced. .

[0021]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below.

The dielectric porcelain in the present invention means a sintered body obtained by molding and firing a green body. When εr is in the range of 24-36, Qf is 7
In order to obtain a dielectric ceramic having a temperature coefficient of resonance frequency of 0000 GHz or more and an absolute value of a temperature coefficient τ _f of 30 ppm / ° C. or less, the dielectric ceramic of the present invention contains at least La, Al, Sr and Ti as metal elements. Consisting of oxides
When the composition formula based on the molar ratio of these metal oxides is expressed as aLa ₂ O ₃ .bAl ₂ O ₃ .cSrO.dTiO ₂ , a, b, c, and d are 0.056 ≦ a ≦ 0.214 0. (110) of a perovskite-type crystal satisfying 056 ≦ b ≦ 0.214 0.300 ≦ c ≦ 0.540 0.220 ≦ d ≦ 0.470 a + b + c + d = 1 and made of a solid solution of LaAlO ₃ and SrTiO ₃ When the X-ray diffraction peak intensity attributable to the plane is A and the X-ray diffraction peak intensity attributable to the (105) plane of Sr ₃ Ti ₂ O ₇ is B, 0.10 ≦ B / A.
It is important to satisfy ≦ 0.60.

The reasons for limiting the molar ratios a, b, c, and d of the respective components to the above ranges in the dielectric ceramic of the present invention are as follows.

That is, 0.056 ≦ a ≦ 0.214 is satisfied when 0.056 ≦ a ≦ 0.214 when εr is 24
The Q value is high in the range of ~ 36, and the temperature coefficient τ _{f of the} resonance frequency is
Is smaller. In particular, 0.080 ≦
a ≦ 0.190 is preferred.

The reason for 0.056 ≦ b ≦ 0.214 is that
When 0.056 ≦ b ≦ 0.214, εr is 24-36
This is because the Q value is high and the absolute value of τ _f is small in the range. Particularly, 0.080 ≦ b ≦ 0.190 is preferable.

The reason for 0.300 ≦ c ≦ 0.540 is that
When 0.300 ≦ c ≦ 0.540, εr is 24-36
This is because the Q value is high and the absolute value of τ _f is small in the range. Particularly, 0.340 ≦ c ≦ 0.490 is preferable.

The reason for setting 0.220 ≦ d ≦ 0.470 is as follows.
When 0.220 ≦ d ≦ 0.470, εr is large and Q
This is because the value is high and the absolute value of τ _f becomes small. Particularly, 0.320 ≦ d ≦ 0.430 is preferable.

In the present invention, the Q value is high when .epsilon.r is in the range of 24 to 36, and in order to reduce the absolute value of .tau.
45 ≦ d / c ≦ 0.85 is particularly preferred. To further reduce the absolute value of τ _f , 0.56 ≦ d / c ≦ 0.7
6 is preferable. Particularly, in order to reduce the absolute value of τ _f , 0.60 ≦ d / c ≦ 0.72 is most preferable.

Further, in the dielectric porcelain of the present invention, 0.1.
10 ≦ B / A ≦ 0.60 means that 0.10 ≦ B / A ≦
For 0.60, because the absolute value of the left tau _f .epsilon.r is maintaining a high Qf in the range of 24 to 36 can be controlled to 30 or less. Outside the range of 0.10 ≦ B / A ≦ 0.60, ε
r is or becomes out of the range of 24 to 36, may become less Qf, because the absolute value of tau _f may become large. Particularly, 0.15 ≦ B / A ≦ 0.45 is preferable.

In the present invention, 0.10 ≦ B / A ≦ 0.6
In the case of 0, the reason why the absolute value of τ _f can be controlled to 30 or less while keeping Qf high in the range of ε r in the range of 24 to 36 is considered as follows.

In the range of εr24-36, the dielectric ceramic
LaAlO contained in_ThreeAnd SrTiO _ThreeFrom a solid solution with
Volume percent of perovskite-type crystals increases with regularization
Qf is thought to be higher_fIs large to minus
There was a problem that it was easy to be heard. This problem was
Sr with respect to the content of the lobskite crystal_ThreeTi_TwoO₇of
The content ratio is within the range of the present invention by the X-ray diffraction peak intensity ratio.
Can solve the problem. For this reason
Is Sr contained in the dielectric porcelain of the present invention._ThreeTi_TwoO ₇Is εr
Is larger than the perovskite crystal, and τf is
This is τ_fIs large to minus
To be able to offset the problem of
available. When B / A is less than 0.10.
Τ at 36_fTends to be negatively large, and B / A is
When it is larger than 0.60, Qf tends to decrease particularly.
Problem.

Further, the dielectric porcelain of the present invention further comprises Sr
_The intensity of the X-ray diffraction peak attributable to the (101) plane of 2TiO ₄ is C,
The X-ray diffraction peak intensity assigned to the (110) plane of SrLaAlO ₄ is D, the X-ray diffraction peak intensity assigned to the (440) plane of Sr ₃ Al ₂ O ₆ is E, and the X-ray diffraction assigned to the (−211) plane of SrAl ₂ O _4. Assuming that the peak intensity is F, 0 ≦ C / A ≦ 0.1
0, 0 ≦ D / A ≦ 0.40, 0 ≦ E / A ≦ 0.20, 0
It is characterized by satisfying at least one of ≦ F / A ≦ 0.20.

0 ≦ C / A ≦ 0.10, 0 ≦ D / A ≦ 0.
40, 0 ≦ E / A ≦ 0.20, and 0 ≦ F / A ≦ 0.20 are satisfied because Qf is not significantly improved in other ranges. The reason is considered as follows.

Sr ₃ Ti ₂ contained in the dielectric porcelain of the present invention
As described above, the crystal phase composed of O ₇ can reduce the absolute value of τ _f in the range of ε r 24 to 36 without lowering Q _f . However, since the perovskite-type crystal and the crystal phase composed of Sr ₃ Ti ₂ O ₇ have different coefficients of thermal expansion, residual stress is present in the sintered body, or ultra-fine cracks or the like are generated. Improvement may not be remarkable. Therefore, in the dielectric porcelain of the present invention, Q
In order to improve f, the residual stress is reduced,
It was necessary to reduce the extremely fine cracks. For that purpose, it is necessary to further include a crystal phase which acts as a moderator of the residual stress, and Sr ₂ TiO ₄ , SrLa
It is considered that at least one of AlO ₄ , Sr ₃ Al ₂ O ₆ , and SrAl ₂ O ₄ acts as the moderating agent. In the present invention, when at least one of C / A, D / A, E / A, and F / A satisfies the above-described formula, it is considered that Qf is improved by the action of the relaxing agent.

The plane assigned peak intensity of the X-ray diffraction peak intensity can be determined as follows with reference to, for example, X-ray diffraction data of JCPDS-ICDD (International Data Center for Diffraction of Powders).

For X-ray diffraction data of JCPDS-ICDD
According to LaAlO_Three(110) plane assigned X-ray diffraction peak
Surface spacing d_LA= 2.682Å, SrTiO_Three(1
10) Plane spacing d of plane-assigned X-ray diffraction peaks_STIs 2.75
9Å and LaAlO_ThreeAnd SrTiO_ThreeFrom a solid solution with
X-ray Diffraction Assigned to (110) Plane of Perovskite Crystal
Peak spacing d_AIs calculated as d_LAAnd d_STExists between
You. Also, Sr_ThreeTi _TwoO₇(105) plane assigned X-ray diffraction
The peak spacing is d_B= 2.83 °, Sr_TwoTiO_Fourof
The plane spacing of the (101) plane-assigned X-ray diffraction peak is d_C= 3.
718 °, SrLaAlO_Four(110) plane attributed X-ray times
The plane spacing of the folding peak is d_D= 2.655 °, Sr _ThreeAl_TwoO₆
The plane spacing of the (440) plane-assigned X-ray diffraction peak is d_E=
2.799Å, SrAl_TwoO_FourX-rays assigned to the (-211) plane
The plane spacing of the diffraction peak is d_F= 3.142Å
The values of these plane spacings vary depending on the measurement conditions, crystal orientation, etc.
D_A, D_B, D_C, D_D, D_EAnd d_F
Is, for example, d_A= 2.70-2.76 °, d_B= 2.8
0 to 2.86 °, d_C= 3.67-3.79 °, d_D=
2.63-2.69Å, d_E= 2.77-2.82 °,
d_F= 3.10 to 3.18 to Å
is there.

Further, in the dielectric porcelain of the present invention, if Sn is further contained at 8.0 parts by weight or less in terms of SnO ₂ ,
It preferred because it is possible to further reduce control the absolute value of tau _f in the range of Ipushiron'aru24～36. In order to improve Qf, it is particularly desirable that Sn be contained in an amount of 6.0 parts by weight or less in terms of SnO ₂ .

In the dielectric porcelain of the present invention, at least a part of the Sn is a crystalline phase of Ti containing Ti.
The solid solution at the site is preferable because the absolute value of τ _f can be controlled further smaller. The Sn
The crystal phase when at least a part of the solid solution forms a solid solution at the Ti site of the crystal phase containing Ti is, for example, Sr ₃ Ti ₂ O
₇ and Sr ₃ Sn ₂ O ₇ . The crystal phase of the solid solution can be confirmed by a scanning electron microscope (TEM) or the like.

In the dielectric ceramic of the present invention, at least one of Mn, W, Ta, and Nb is further converted to MnO ₂ , WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ , respectively, for a total of 3.0. When the content is not more than part by weight, Qf can be remarkably improved. Particularly, at least one of Mn, W, Ta, and Nb is MnO ₂ , WO ₃ , Ta ₂ O ₅ ,
Nb ₂ O ₅ to contain less total from 0.001 to 1.5 parts by weight in terms of desirable to improve the Qf.

Next, a method for manufacturing a dielectric ceramic according to the present invention will be described. The dielectric porcelain of the present invention is, for example, the following (1)
A) to (3A).

(1A) La ₂ O ₃ and Al ₂ O ₃ powders having a purity of 99% or more were prepared as raw material powders, weighed in predetermined amounts, mixed and pulverized.
Calcination is carried out at a temperature of 1400 ° C. for 1 hour or more. The calcined powder is pulverized with a median diameter of 0.4 to 0.8 μm.
Crushed. A binder is added to the pulverized powder, and granulation is performed by a known method, for example, a spray drying method, and the average particle size of the granulated powder after removing the 350 μm or more granulated powder is 70 to 10 μm.
Granulation conditions are controlled so as to be 0 μm, and a granulated powder P is obtained.

(2A) Purity 99% or more as raw material powder
SrCO_Three, SnO_TwoAnd TiO _TwoPrepare the powder of
These are weighed in predetermined amounts, mixed and pulverized, and the obtained powder is
A temperature lower than the calcination temperature of (1A) described above, for example, 1
Hold at a temperature of 100 or more and less than 1300 ° C for 1 hour or more
Calcine. MnCO added to the calcined powder_Three, WO_Three, Ta
_TwoO_Five, Nb_TwoO_FiveIs added in a predetermined amount, and the crushed particle size is the median diameter.
And pulverize to 0.4-0.8 μm. By the ground powder
And a known method such as a spray drying method.
Of the granulated powder after granulating and removing the granulated powder of 350 μm or more.
Granulation conditions are controlled so that the average particle size is 30-65μm
Then, granulated powder Q is obtained.

(3A) The granulated powder A and the granulated powder B are uniformly mixed, formed into a predetermined shape by a known method such as press molding or a doctor blade method, then debindered, and then in the air or an atmosphere containing oxygen. After firing at 1500 to 1600 ° C. for 1 to 5 hours in the inside, 1500 to 1000 ° C.
Is controlled at a rate of 10 to 50 ° C./hour to lower the temperature.

In the obtained dielectric porcelain, LaAlO
₃ and SrTiO ₃ (the 110) plane attributed X-ray diffraction peak intensity of the perovskite type crystal comprising a solid solution of A, Sr ₃
Assuming that the (105) plane assigned X-ray diffraction peak intensity of Ti ₂ O ₇ is B, to satisfy 0.10 ≦ B / A ≦ 0.60, the calcination temperature, the pulverized particle size, and the It is important that the particle size and firing conditions are as described above.

In particular, by controlling the average particle size of the granulated powder P and the granulated powder Q within the above range, the X-ray diffraction peak intensity ratios B / A, C / A, D / A, and E / A described above. , F / A can be controlled.

In order to dissolve at least a part of Sn at the Ti site of the crystal phase containing Ti, it is important to perform calcination under the calcination conditions described in the above (2A).

The dielectric porcelain of the present invention is particularly suitably used as a dielectric resonator. FIG. 1 shows a TE mode dielectric resonator according to one embodiment. This TE mode type dielectric resonator is configured by providing an input terminal 2 and an output terminal 3 on opposite sides of an inner wall of a metal case 1 and disposing the dielectric ceramic 4 between the input / output terminals 2 and 3. The microwave is input from the input terminal 2, and the input microwave is confined in the dielectric porcelain 4 by reflection at the boundary between the dielectric porcelain 4 and free space, and resonates at a specific frequency. This signal is electromagnetically coupled to the output terminal 3 and output.

The dielectric resonator using the dielectric porcelain of the present invention is not limited to the above-described TE mode type, but may be a coaxial type resonator using a TEM mode, a strip line resonator, or a TM mode type. May be applied to the dielectric porcelain resonator described above and other resonators. Further, the input terminal 2 and the output terminal 3 may be provided directly on the dielectric porcelain 4.
The shape of the dielectric ceramic 4 may be a rectangular parallelepiped, a cube, a plate, a disk, a column, a polygon, or any other three-dimensional shape capable of resonance.
It is about 3 to 300 GHz, and the resonance frequency is about 0.1 GHz.
About 6 to 80 GHz is practically preferable.

[0049]

Next, examples of the present invention will be described.

As a raw material powder, La ₂ having a purity of 99% or more is used.
O ₃ and Al ₂ O ₃ powders were prepared, weighed, mixed, and pulverized at the ratios shown in Table 1, and the obtained powder was 135
It was calcined while being kept at 0 ° C. for 2 hours. The calcined powder was wet-pulverized to a pulverized particle diameter of 0.4 to 0.8 μm in median diameter.
A binder is added to the slurry obtained after the pulverization and granulated by a spray drying method, and spray dried so that the average particle diameter of the granulated powder after removing the granulated powder of 350 μm or more is 70 to 100 μm. The conditions were controlled to obtain granulated powder R.

Next, powders of SrCO ₃ , SnO _2, and TiO ₂ having a purity of 99% or more were prepared as raw material powders, weighed, mixed, and pulverized at the ratios shown in Table 1, and the obtained powder was 1200 Calcination was carried out at a temperature of 2 ° C. for 2 hours. To the calcined powder, MnCO ₃ , WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ were added in the amounts shown in Table 1, and the pulverized particle diameter was 0.1 in median diameter.
Wet pulverization to 4-0.8 μm. A binder was added to the slurry obtained after the pulverization, and the mixture was granulated by a spray drying method.
Granulation conditions were controlled so that the average particle size of the granulated powder after removing the granulated powder of 50 μm or more was 30 to 65 μm, and a granulated powder S was obtained.

The granulated powder R and the granulated powder S were uniformly mixed and press-formed at a pressure of 1 ton / cm ² into a column having a diameter of 12 mm and a height of 6.5 mm as a sample for evaluating dielectric properties. The obtained molded body is debindered, and is heated at 1500 to 1600 ° C. in the air or in an atmosphere containing oxygen.
The sintering was carried out for a period of time, and the temperature was lowered at a rate of 1500 to 1000 ° C at 20 ° C / hour.

The sample thus obtained was 9.5 mm in diameter.
The sample was polished to a thickness of 4.8 mm to obtain a sample of the dielectric ceramic of the present invention.

In Table 1, the added MnCO ₃
Was converted to MnO ₂ .

Next, in order to evaluate the dielectric characteristics of the obtained sample, the relative permittivity εr and the Q value at a frequency of 7.5 to 9.5 GHz were measured using the sample by a dielectric cylinder resonator method. The value Qf represented by the product of the Q value and the measurement frequency f was calculated. Further, the resonance frequency in the temperature range of -40 to 85 ° C was measured, and the temperature coefficient τ _f of the resonance frequency was calculated based on the resonance frequency at 25 ° C.

In Table 1, τ _f1 is −40 ° C. to 25
° C is the temperature coefficient of the resonance frequency, and τ _f2 is 25 ° C to 85 ° C.
It is the temperature coefficient of the resonance frequency of ° C.

Further, the crystal phase of the above sample was measured by an X-ray diffraction method, and the (110) plane assigned X-ray diffraction peak intensity A, Sr ₃ Ti ₂ O of perovskite type crystal composed of a solid solution of LaAlO ₃ and SrTiO ₃ was measured. _7, the (105) plane assigned X-ray diffraction peak intensity B, Sr ₂ TiO ₄ (101) plane assigned X-ray diffraction peak intensity C, SrLaAlO ₄ (110) plane assigned X-ray diffraction peak intensity D, Sr ₃ Al ₂ O ₆ (440)
Plane assigned X-ray diffraction peak intensity E, (−21) of SrAl ₂ O ₄
1) The plane assigned X-ray diffraction peak intensity F was determined, and B / A, C /
The values of A, D / A, E / A and F / A were calculated. FIG.
FIG. 11 shows a graph of X-ray diffraction of No. 11.

The Sn contained in the sample of the present invention is T
It was confirmed by TEM that the solid solution was dissolved in the crystal containing i.

Table 1 shows the results.

As is clear from Table 1, the dielectric ceramic of the present invention (Sample Nos. 1 to 21) has a Qf of 70,000 GHz or more and a temperature coefficient τ _f of the resonance frequency in the range of εr of 24 to 36. Excellent characteristics having an absolute value of 30 ppm / ° C. or less were obtained.

In particular, Sample No. containing SnO ₂ was used. 8 ~
In No. 15, the absolute value of τ _f was reduced to 15 ppm / ° C. or less. Sample No. containing at least one of Mn, W, Ta, and Nb in a total of 3.0 parts by weight or less in terms of MnO ₂ , WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ respectively. 8, 9-1
As for 6, 18 to 21, Qf was as high as 84000 to 93000. Also, the value of d / c is 0.45 ≦ d / c ≦
Sample No. 0.85 For 8 to 19, the absolute value of τ _f is 24p
A value as small as pm / ° C. or less was obtained.

[0062]

[Table 1]

On the other hand, as a comparative example, the dielectric porcelain having a molar ratio out of the range of the present invention (samples Nos. 28 to 35) had εr
Is out of the range of 24-36, Qf is low,
The absolute value of τ _f became larger than 30 ppm / ° C.

Further, as a comparative example, a dielectric porcelain (sample Nos. 22 to 2) whose manufacturing method is different from that of the sample of the present invention.
7) was produced as follows.

That is, La ₂ O ₃ and Al ₂ O ₃ were mixed and pulverized, calcined at 1100 ° C. for 2 hours, pulverized to a median diameter of 2.1 to 3.0 μm, and then spray-dried. To obtain a granulated powder E having an average particle size of 30 to 50 μm after removing the granulated powder of 350 μm or more. Next, SrCO ₃ , SnO ₂ and TiO ₂ were mixed and pulverized, held at 1400 ° C. for 2 hours, calcined, and then MnCO ₃ ,
WO ₃ , Ta ₂ O ₅ , and Nb ₂ O ₅ were added, and further, after the wet pulverization was performed to a median diameter of 2.1 to 3.0 μm, granulation was performed by a spray drying method, and a granulated powder of 350 μm or more was obtained. From which the average particle size of the granulated powder after removal of the powder was 100 to 150 μm. The granulated powder E and the granulated powder F are mixed and press-formed at a pressure of 1 ton / cm ² into a column having a diameter of 12 mm and a height of 6.5 mm as a sample for evaluating dielectric properties. After the binder, in the air 1500-160
Hold at 0 ° C. for 0.5 hour and fire, 1500-1000
The temperature was lowered at a rate of 200 ° C./hour.

As a result, as can be seen from Table 1, the dielectric porcelains (samples Nos. 22 to 27) outside the range of the present invention had an εr
Is out of the range of 24-36, Qf is low,
The absolute value of τ _f became larger than 30 ppm / ° C.

[0067]

According to the dielectric porcelain of the present invention, La
₂ O ₃ , Al ₂ O ₃ , SrO, TiO ₂ contained in a specific range,
In addition, by controlling the crystal phase, the relative dielectric constant
In the range of ~ 36, Qf is high, it is possible to reduce the absolute value of the temperature coefficient tau _f of the resonance frequency. As a result, the present invention 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.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a dielectric resonator of the present invention.

FIG. 2 is a graph showing one example of X-ray diffraction of the dielectric ceramic of the present invention.

[Explanation of symbols]

 1: metal case 2: input terminal 3: output terminal 4: dielectric porcelain

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01P 7/10 H01P 7/10

Claims (6)

[Claims] 1. At least La, Al, S as a metal element
When the composition formula based on the molar ratio of these metal oxides is represented by aLa ₂ O ₃ .bAl ₂ O ₃ .cSrO.dTiO ₂ , a, b, c, and d are represented by: 0.056 ≦ a ≦ 0.214 0.056 ≦ b ≦ 0.214 0.300 ≦ c ≦ 0.540 0.220 ≦ d ≦ 0.470 a + b + c + d = 1, and LaAlO ₃ and SrTiO ₃ Assuming that the (110) plane-assigned X-ray diffraction peak intensity of the perovskite type crystal composed of a solid solution of A is A and the (105) plane-assigned X-ray diffraction peak intensity of Sr ₃ Ti ₂ O ₇ is B, 0.10 ≦ B / A
A dielectric porcelain satisfying ≦ 0.60. 2. The X-ray diffraction peak intensity assigned to the (101) plane of Sr ₂ TiO ₄ is C, the X-ray diffraction peak intensity assigned to the (110) plane of SrLaAlO ₄ is D, and (440) of Sr ₃ Al ₂ O _6.
The plane-assigned X-ray diffraction peak intensities of E and SrAl ₂ O ₄ were (−2).
11) When the X-ray diffraction peak intensity assigned to the plane is F, 0 ≦
C / A ≦ 0.10, 0 ≦ D / A ≦ 0.40, 0 ≦ E / A
≦ 0.20, at least one of 0 ≦ F / A ≦ 0.20
The dielectric porcelain according to claim 1, wherein the dielectric ceramic is satisfied. 3. The dielectric ceramic according to claim 1, wherein Sn is contained in an amount of 8.0 parts by weight or less in terms of SnO ₂ . 4. The dielectric ceramic according to claim 3, wherein at least a part of said Sn is dissolved in a Ti site of a crystal phase containing Ti. 5. At least one of Mn, W, Ta, and Nb
The dielectric ceramic according to any one of claims 1 to 4, characterized in that it contains seeds respectively _{MnO 2, WO 3, Ta 2} O 5, Nb 2 O 5 in terms of a total 3.0 parts by weight or less. 6. A dielectric resonator, wherein the dielectric ceramic according to claim 1 is arranged between a pair of input / output terminals.