JP2003238242A - Dielectric porcelain and dielectric resonator using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a dielectric porcelain having high εr, a high Q value and a small absolute value of the temperature coefficient τ<SB>f</SB>of the resonance frequency in a high frequency region. <P>SOLUTION: The dielectric porcelain comprises an oxide having a specific composition wherein a rare earth element (Ln), Al, M (M is Ca and/or Sr) and Ti are contained as metal elements, and the dielectric porcelain contains crystallites having diameters of 100 to 1,000 Å. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic and a dielectric resonator having a high relative permittivity .epsilon.r and a resonance sharpness Q value in a high frequency region such as a microwave and a millimeter wave. Related to various resonator materials, dielectric substrate materials for MIC (Monolithic IC), dielectric waveguide materials, dielectric ceramics used for multilayer ceramic capacitors, etc. and dielectric resonators using the same .

[0002]

2. Description of the Related Art Dielectric ceramics are widely used in dielectric resonators, MIC dielectric substrates, waveguides, etc. in a high frequency range such as microwaves and millimeter waves. The required characteristics are: (1) the wavelength of the electromagnetic wave propagating in the dielectric is shortened to (1 / εr) ^1/2 , so that the relative permittivity is large with respect to the demand for miniaturization; 2) Small dielectric loss in high frequency range, that is, high Q, (3)
The above three characteristics are mainly mentioned that 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.

As such a dielectric ceramic, for example, Japanese Patent Laid-Open No. 4-118807 discloses CaO—TiO ₂ —Nb ₂ O.
_A dielectric ceramic made of a _5- DO (D is Zn, Mg, Co, Mn, etc.) system is shown. However, in this dielectric porcelain, the Q value when converted to 1 GHz is 1600 to 2500.
It is as low as 0 and the temperature coefficient τf of the resonance frequency is 215-8.
Since it is as large as about 35 ppm / ° C., there are problems of improving the Q value and reducing τ _f .

Therefore, the applicant of the present invention has found that the LnAlCaTi-based dielectric ceramics (see Japanese Patent Laid-Open No. 6-76633, Ln
Is a rare earth element), an LnAlSrCaTi-based dielectric ceramic (see Japanese Patent Laid-Open No. 11-278927), and LnAlC.
Dielectric porcelain of aSrBaTi system (JP-A-11-1062)
No. 55).

[0005]

[Problems to be Solved by the Invention] However, LnAlCa
Ti-based dielectric porcelain (see JP-A-6-76633,
In the case where Ln is a rare earth element), the Q value is 20000 to 58000 in the range of relative permittivity εr of 30 to 47, and in some cases, the Q value becomes smaller than 35000, so that there is a problem that the Q value needs to be improved. there were.

Further, in the LnAlSrCaTi system dielectric ceramics (see Japanese Patent Laid-Open No. 11-278927), the relative permittivity ε.
Q value of 20000 to 75 in the range of r of 30 to 48
000, and in some cases also has a Q value of 35,000.
There is a problem that it is necessary to improve the Q value because it becomes smaller.

Further, in the LnAlCaSrBaTi-based dielectric ceramic (see Japanese Patent Laid-Open No. 11-106255), the relative permittivity εr is 31 to 47 and the Q value is 30,000 to 6800.
Since it is 0, and the Q value becomes smaller than 35000 in some cases, there is a problem that the Q value needs to be improved.

The present invention has been completed in view of the above circumstances, and its object is to have a Q value of 43000 or more in the range of relative permittivity εr of 30 to 48, and particularly a Q value of 46000 or more in the range of εr of 40 or more. And high relative permittivity εr
It is an object of the present invention to provide a dielectric ceramic and a dielectric resonator that have small temperature dependence and are stable.

[0009]

The dielectric porcelain of the present invention comprises:
At least rare earth elements (Ln), Al, and
When M (M is Ca and / or Sr) and Ti is contained and the composition formula is expressed as aLn ₂ O _x .bAl ₂ O ₃ .cMO.dTiO ₂ (where 3 ≦ x ≦ 4), the molar ratio a , B, c,
d is 0.056 ≦ a ≦ 0.214 0.056 ≦ b ≦ 0.214 0.286 ≦ c ≦ 0.500 0.230 <d <0.470 a + b + c + d = 1, and the crystallite diameter is It is characterized in that it is 100 to 1000Å.

The rare earth element (Ln) is La and / or Nd.

Further, the lattice strain of the dielectric ceramic is 0.3.
% Or less.

In the above dielectric ceramic, at least one of Mn, W, Nb and Ta as a metal element is added in a total amount of 0.01 in terms of MnO ₂ , WO ₃ , Nb ₂ O ₅ and Ta ₂ O _5. It is characterized by containing ~ 3% by weight.

Further, the dielectric resonator of the present invention is one in which the dielectric ceramic is arranged between a pair of input / output terminals to constitute a dielectric resonator which operates by electromagnetic field coupling.

[0014]

In the dielectric ceramics of the present invention, at least rare earth elements (Ln), Al, M (M is Ca and / or
Or Sr) and Ti and the composition formula is expressed as aLn ₂ O _x .bAl ₂ O ₃ .cMO.dTiO ₂ (provided that 3 ≦ x ≦ 4), the molar ratios a, b, c,
d is 0.056 ≦ a ≦ 0.214 0.056 ≦ b ≦ 0.214 0.286 ≦ c ≦ 0.500 0.230 <d <0.470 a + b + c + d = 1, and the crystallite size is The Q value can be improved by setting it to 100 to 1000Å.

In the dielectric ceramic of the present invention, the Q value can be further improved by using La and / or Nd as the rare earth element (Ln).

In the dielectric ceramic of the present invention, the Q value can be further improved by setting the lattice strain to 0.3% or less.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below.

The dielectric porcelain in the present invention means a polycrystalline sintered body obtained by molding and firing an unsintered body. In order to increase the Q value, the dielectric ceramic of the present invention uses at least a rare earth element (L
n), Al, M (M is Ca and / or Sr), and Ti, and the composition formula is shown as aLn ₂ O _x .bAl ₂ O ₃ .cMO.dTiO ₂ (provided that 3 ≦ x ≦ 4). When the molar ratio a, b, c,
d is 0.056 ≦ a ≦ 0.214 0.056 ≦ b ≦ 0.214 0.286 ≦ c ≦ 0.500 0.230 <d <0.470 a + b + c + d = 1, and the crystallite size is It is important to set 100 to 1000Å to increase the Q value.

In the dielectric porcelain of the present invention, the reason for limiting the molar ratios a, b, c, d of the respective components to the above ranges is as follows.

That is, 0.056 ≤ a ≤ 0.214 means that when 0.056 ≤ a ≤ 0.214, εr is large, the Q value is high, and the absolute value of the temperature coefficient τ _f of the resonance frequency is set. Is small. In particular, the lower limit of a is preferably 0.078 and the upper limit of a is preferably 0.1866.

The reason for setting 0.056 ≦ b ≦ 0.214 is that
When 0.056 ≦ b ≦ 0.214, εr is large and Q
This is because the value is high and the absolute value of τ _f is small. In particular, the lower limit of b is preferably 0.078 and the upper limit of b is 0.
1866 is preferred.

The reason why 0.286≤c≤0.500 is that
When 0.286 ≦ c ≦ 0.500, εr is large and Q
This is because the value is high and the absolute value of τ _f is small. In particular, the lower limit of c is preferably 0.330 and the upper limit of c is 0.
470 is preferred.

The reason for setting 0.230 <d <0.470 is that
When 0.230 <d <0.470, εr is large and Q
This is because the value is high and the absolute value of τ _f is small. In particular, the lower limit of d is preferably 0.340, and the upper limit of d is 0.
450 is preferred.

In the present invention, 0.75 ≦ (b + d) / (a + c) ≦ 1.25 is preferable in order to increase the Q value. To further increase the Q value, (b + d) / (a +
The lower limit of c) is particularly preferably 0.85, and (b + d) /
The upper limit of (a + c) is particularly preferably 1.15.

In the dielectric ceramic of the present invention, the Q value can be increased by setting the crystallite diameter to 100 to 1000Å, and particularly excellent dielectric characteristics can be obtained as a dielectric ceramic for a resonator. it can. Here, the reason why the Q value becomes high when the crystallite size is within the range of the present invention is as follows.
It can be considered as follows.

The dielectric ceramic of the present invention is a polycrystalline body. The crystal contained in the polycrystalline body is composed of a plurality of crystallites. The electromagnetic wave propagating through the crystal is attenuated at the interface of the crystallite with a large dielectric loss, and the attenuated electromagnetic wave is converted into heat energy or the like, resulting in a decrease in Q value. If the crystallite diameter is smaller than 100Å, the area of the interface between the crystallites increases and the Q value decreases. On the other hand, the crystallite size is 100
When it is larger than 0 Å, the crystallinity of the crystal contained in the polycrystalline body becomes small, so that the Q value is considered to decrease. It is considered that when the crystallite diameter is within the range of the present invention, the dielectric loss is small and the crystallinity of the crystal is large, so that a dielectric ceramic having a high Q value can be obtained.

In order to further improve the Q value in the dielectric ceramics of the present invention, the upper limit of the crystallite diameter of the crystals forming the polycrystal is preferably 750Å. In particular, in order to improve the Q value, it is particularly desirable that the upper limit of the crystallite size is 650Å. In order to improve the Q value most, the upper limit of the crystallite size is most preferably 550Å. The crystallite size in the present invention is preferably a value obtained by averaging the crystallite sizes. Further, in order to further improve the Q value in the dielectric ceramics of the present invention, the lower limit of the crystallite diameter of the crystals constituting the polycrystal is preferably 200Å. In particular, in order to improve the Q value, it is particularly desirable that the lower limit of the crystallite size is 300Å.

Among the crystals contained in the dielectric ceramics of the present invention, at least rare earth elements (Ln) and A are used as metal elements.
It is desirable that the proportion of the polycrystal having an oxide containing l, M (M is Ca and / or Sr), and Ti as a main component is 90% by volume or more.

In the dielectric ceramic of the present invention, at least rare earth elements (Ln), Al, M (M is C
a and / or Sr) and Ti respectively as LnO
It is desirable to contain _{(X + 3) / 2} (3 ≦ x ≦ 4), Al ₂ O ₃ , MO (M is Ca and / or Sr), and 85% by weight or more in total in terms of TiO ₂ .

The crystal composed of the main component is LnAlO.
_{(X + 3) / 2} (3 ≦ x ≦ 4) and MTiO ₃ (M is Ca and /
Alternatively, a perovskite type crystal composed of a solid solution with Sr) is preferable, and examples thereof include NdAlO ₃ and SmA.
at least one of LaO ₃ and LaAlO ₃ , and CaTi
It is desirable to be made of a solid solution with at least one of O ₃ and SrTiO ₃ .

Further, in the dielectric ceramic of the present invention, it is desirable that the rare earth element (Ln) is La and / or Nd in order to increase the Q value particularly. Here, that the rare earth element (Ln) is composed of La and / or Nd means that La / and Nd are 90% by weight or more in the rare earth element contained in the dielectric ceramic of the present invention.

Further, in the dielectric ceramic of the present invention, it is important that the lattice strain is 0.3% or less in order to improve the Q value. The reason for this is that if the lattice strain is larger than 0.3%, the Q value is not significantly improved. In particular, in order to improve the Q value, the upper limit of lattice strain is preferably 0.2%.

The dielectric ceramic of the present invention is preferably made of the perovskite type crystal. In the ABO ₃ type (A and B are metallic elements) perovskite type crystals,
A crystalline structure in which the metallic elements of the sites and B sites are regularly arranged and the number of oxygen defects is small, the lattice strain is small and a high Q value can be obtained. In the case of the dielectric porcelain of the present invention, A
The site atoms consist of rare earth elements and Ca and / or Sr, and the B site atoms consist of Al and Ti. In the dielectric porcelain of the present invention, A sites and B sites are regularly arranged, and further, oxygen defects are few, so that lattice distortion is small, and as a result, the Q value is considered to be high. In the dielectric porcelain of the present invention, like the manufacturing method described later,
By performing heat treatment in a high-temperature and high-pressure atmosphere containing oxygen, A sites, B sites and oxygen atoms are regularly arranged, and further oxygen defects are reduced, whereby a dielectric ceramic with a small lattice strain can be obtained.

The crystallite diameter and lattice strain of the crystal contained in the dielectric ceramics of the present invention are measured by the Hall method or the like. Specifically, for example, using an X-ray diffractometer, the crystallite size and lattice strain of the sample are measured by the Hall method as follows.

The device constants of the X-ray diffractometer are corrected by the external standard sample method (SRM640b) using Si by the Si Miller indices (111), (220), (311), (4).
00), (331), (422), (511), (44
0) and (531) planes are used. For example, rare earth, A
In the measurement of the crystallite size and the lattice strain of the sample containing 1, Sr and Ti, the Miller indices (100), (110), (111), (20) of cubic SrTiO ₃ were measured.
0), (210), (211), (220) and (3
10) Using the surface, measurement is performed by the integral width method.

Further, in the dielectric ceramic of the present invention, at least one of Mn, W, Nb and Ta as a metal element is converted to MnO ₂ , WO ₃ , Nb ₂ O ₅ and Ta ₂ O ₅ in an amount of 0.01 to. It contains 3% by weight. At least one of Mn, W and Ta is MnO ₂ , WO ₃ and N.
The reason for containing 0.01 to 3% by weight in terms of b ₂ O ₅ and Ta ₂ O ₅ is that the inclusion of 0.01 to 3% by weight significantly improves the Q value. To increase the Q value, Mn, W,
At least one of Nb and Ta is Mn in the total amount.
Especially 0.0 in terms of O ₂ , WO ₃ , Nb ₂ O ₅ and Ta ₂ O _5.
It is preferable that the content of Mn be 2 to 2% by weight.
It is preferable to contain 0.02 to 0.5% by weight in terms of O ₂ .

Further, Mn, W, Nb and Ta are replaced with MnO.
₂ , 0.01 to 0.01 in terms of WO ₃ , Nb ₂ O ₅ and Ta ₂ O ₅
It is considered that the oxygen content in the solid solution can be reduced and the Q value can be further increased by including it in a weight percentage.

The method of manufacturing the dielectric ceramics of the present invention specifically comprises, for example, the following steps (1a) to (6a).

(1a) High-purity rare earth oxides and powders of aluminum oxide, calcium carbonate, strontium carbonate and titanium oxide were used as starting materials, weighed to a desired ratio, and pure water was added. , The average particle size of the mixed raw material is 2.0 μm or less, preferably 0.6 to 1.4
The mixture is obtained by wet mixing and pulverizing with a ball mill using zirconia balls or the like for 1 to 100 hours until it becomes μm.

(2a) After drying this mixture, 1100-
Calcination is performed at 1300 ° C. for 1 to 10 hours to obtain a calcined product.

(3a) The obtained calcined product was mixed with manganese carbonate (MnCO ₃ ), tungsten oxide (WO ₃ ) and tantalum oxide (Ta ₂ O ₅ ) and pure water was added to obtain an average particle size of 2 Wet mixing and pulverization are performed by a ball mill using zirconia balls or the like for 1 to 100 hours until the thickness becomes 0.0 μm or less, preferably 0.6 to 1.4 μm.

(4a) Further, 3 to 10% by weight of a binder is added, dehydrated, and then granulated or sized by a known method such as a spray drying method to obtain the obtained granule or sized powder. Is molded into a desired shape by a known molding method such as a die pressing method, a cold isostatic pressing method, an extrusion molding method, or the like. The form of the granulated body or the sized powder may be not only solid such as powder but solid such as slurry and liquid mixture. In this case, the liquid may be a liquid other than water, for example, IPA (isopropyl alcohol), methanol, ethanol, toluene, acetone or the like.

(5a) The obtained molded body was placed in the atmosphere at 1600
The temperature is kept at ℃ to 1700 ℃ for 5 to 10 hours for firing.

(6a) 5% by volume of oxygen is added to the obtained fired body.
In the gas containing the above, the temperature is 1500 to 1700 ° C.,
Heat treatment is performed at a pressure of 300 to 3000 atm for 1 minute to 100 hours. Preferably, in a mixed gas composed of 5 to 30% by volume of oxygen gas and the balance gas of an inert gas such as Ar,
Heat treatment is performed at a temperature of 1550 to 1650 ° C. and a pressure of 1000 to 2500 atm for 20 minutes to 3 hours.

In the method for manufacturing a dielectric ceramic of the present invention,
Especially by using the step (6a), the crystallite diameter can be controlled within the range of 100 to 1000Å. In particular, when the firing temperature is T ₁ and the heat treatment temperature is T ₂ , the crystallite size is 20 when T ₁ −T ₂ = −30 to 70 ° C.
It can be controlled from 0 to 750Å. Furthermore, by controlling the pressure and heat treatment time in the step 6 (a), the lattice strain can be controlled to be small. For example, by performing the heat treatment for 20 minutes to 3 hours at a pressure of 1500 to 2000 atm and a temperature of T ₁ −T ₂ = −10 to 50 ° C., the lattice strain is 0.3%.
It can be: In the dielectric porcelain of the present invention, the firing temperature T ₁ varies depending on the porcelain composition, the average particle size after pulverization, and the like, so it is desirable that the heat treatment temperature T ₂ also changes accordingly.

It is difficult to control the crystallite diameter and the lattice distortion within the range of the present invention in the dielectric ceramic that does not go through the step 6 (a), and as a result, the Q value decreases. That is,
The crystallite diameter of the dielectric porcelain manufactured without passing through the step '(6a) becomes larger than 1000Å.

Furthermore, the dielectric ceramic of the present invention further comprises Zn
O, NiO, Fe ₂ O ₃ , SnO ₂ , Co ₃ O ₄ , ZrO ₂ ,
LiCO ₃ , Rb ₂ CO ₃ , Sc ₂ O ₃ , V ₂ O ₅ , CuO,
_{SiO 2, BaCO 3, MgCO 3} , Cr 2 O 3, B 2 O 3,
GeO ₂ , Sb ₂ O ₅ , Ga ₂ O ₃ or the like may be added. Although these depend on the added components, the main component 10 is used for the purpose of optimizing the values of εr and the temperature coefficient τ _f of the resonance frequency.
It can be added in a proportion of 5 parts by weight or less with respect to 0 parts by weight.

The dielectric ceramic of the present invention is most preferably used as a dielectric ceramic of a dielectric resonator. In Figure 1, T
A schematic diagram of an E-mode type dielectric resonator is shown. The dielectric resonator of 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 these input / output terminals 2 and
A dielectric porcelain 4 composed of the above-mentioned dielectric porcelain is arranged between the three. 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 ceramic 4 by the reflection of the boundary between the dielectric ceramic 4 and the free space, and the specific Resonates at the frequency. This signal is electromagnetically coupled to the output terminal 3 and output.

Although not shown, the dielectric ceramic of the present invention may be applied to a coaxial resonator using TEM mode, a strip line resonator, a TM mode dielectric ceramic resonator, and other resonators. Of course. Further, the dielectric resonator can be configured by directly providing the input terminal 2 and the output terminal 3 on the dielectric ceramic 4.

The above-mentioned dielectric porcelain 4 is a resonance medium of a predetermined shape made of the dielectric porcelain of the present invention, and its shape is a rectangular parallelepiped, a cube, a plate, a disk, a cylinder, a polygonal prism, or any other resonance. Any three-dimensional shape will do. The frequency of the input high frequency signal is about 1 to 500 GHz, and the resonance frequency is preferably about 2 GHz to 80 GHz for practical use.

The present invention is not limited to the above embodiment, and various modifications may be made without departing from the spirit of the present invention.

[0052]

EXAMPLE A sample of the present invention was prepared as shown in the following (1b) to (7b).

(1b) High-purity rare earth oxides and aluminum oxide, calcium carbonate, strontium carbonate, and titanium oxide powders were used as starting materials, weighed to a desired ratio, and pure water was added. A mixture was obtained by wet mixing and pulverizing with a ball mill using zirconia balls until the average particle diameter of the mixed raw material became 1.0 μm or less.

(2b) After drying the mixture, the temperature is 1200 ° C.
It was calcined for 5 hours to obtain a calcined product.

(3b) The obtained calcined product was mixed with manganese carbonate (MnCO ₃ ), tungsten oxide (WO ₃ ) and tantalum oxide (Ta ₂ O ₅ ) and pure water was added to obtain an average particle size of 1 Wet mixing and pulverization were performed by a ball mill using zirconia balls or the like for 1 to 100 hours until the particle size became 0.0 μm or less.

(4b) Further, 3 to 10% by weight of a binder was added, followed by dehydration, and then granulation was carried out by a spray dry method, and the obtained granulated body was molded by a die pressing method. (5b) The obtained molded product was heated to 1600 ° C. to 1700 ° C. in the atmosphere.
It was held at 8 ° C. for 8 hours for firing.

(6b) The obtained fired body was heated at a temperature of 1 in a gas containing 20% by volume of oxygen and 80% by volume of argon.
10 at 500 to 1700 ° C and a pressure of 500 to 2000 atm
Heat treatment was performed for 3 minutes to 3 hours to obtain a heat-treated body.

(7b) The disk portion (main surface) and side surface of the obtained heat-treated body were polished and ultrasonically cleaned in acetone,
It was dried at 150 ° C. for 1 hour.

Then, the relative permittivity εr, the Q value, and the temperature coefficient τf of the resonance frequency were measured at a measurement frequency of 3.5 to 4.5 GHz by the cylindrical resonator method. Q value generally holds in microwave dielectrics (Q value) x (measurement frequency f)
= (Constant), it was converted to a Q value at 1 GHz.
Regarding the temperature coefficient of the resonance frequency, the temperature coefficient τ _f of 25 to 85 ° C. was calculated based on the resonance frequency at 25 ° C.

RINT1400 manufactured by Rigaku Denki Co., Ltd.
Using a V-type X-ray diffractometer, the crystallite size and lattice distortion of the sample were measured by the Hall method. The device constant of the X-ray diffractometer is corrected by the external standard sample method (SRM) using Si.
640b), the Si Miller indices (111), (2
20), (311), (400), (331), (42
2), (511), (440) and (531) planes were used. Further, for example, in measuring the crystallite size and the lattice distortion of a sample containing rare earths, Al, Sr, and Ti, Miller indices (100), (1 of cubic SrTiO ₃
10), (111), (200), (210), (21)
It was measured by the integral width method using 1), (220) and (310) planes.

The results are shown in Tables 1 and 2. In Table 1, for example, the ratio of rare earth elements is 0.1Y · 0.9.
The La sample indicates that the molar ratio of Y to La is 0.1: 0.9, for example, the sample in which the ratio of the rare earth element is La is a sample in which La is used as the rare earth.

As is clear from Tables 1 and 2, sample No. within the scope of the present invention. 1 to 48 have a relative permittivity εr of 30 to 4
The Q value when converted to 8 and 1 GHz was 43000 or higher, especially when the εr was 40 or higher, the Q value was 46000 or higher, and excellent dielectric properties within τ _f ± 30 (ppm / ° C) were obtained. .

On the other hand, the above (1b) to (5b) and (7)
As a result of producing dielectric ceramics (Sample Nos. 49 to 53) outside the range of the present invention using the step b), εr was low, Q value was low, and the absolute value of τ _f was large.
From these results, it was revealed that the sample manufactured without passing through the step (6b) had poorer dielectric properties than the sample within the scope of the present invention.

Sample No. 54, 55 and 56
Is a sample No. of the example of Japanese Patent Laid-Open No. 6-76633, which is a conventional technique. 13, the sample No. of the example of JP-A-11-106255. 14 and the sample No. of the examples of JP-A-11-278927. It is the same dielectric porcelain as No. 12. These No. In the samples Nos. 54 to 56, the crystallite size was out of the range of the present invention, and the Q value was as low as 30,000 or less. From this, it has been clarified that it is difficult to control the crystallite diameter within the range of the present invention in the conventional dielectric ceramic, and the Q value is low.

[0065]

[Table 1]

[0066]

[Table 2]

[0067]

INDUSTRIAL APPLICABILITY In the present invention, at least rare earth elements (Ln), Al, M (M is Ca and /
Alternatively, it is possible to obtain a high relative permittivity εr and a high Q value in a high frequency region by using a dielectric porcelain composed of an oxide having a specific composition containing Sr) and Ti and having a crystallite diameter of 100 to 1000Å. it can. As a result, it can be applied to resonator materials used in the microwave and millimeter wave regions, MIC dielectric substrate materials, dielectric waveguides, dielectric antennas, and other various electronic components.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a dielectric resonator of the present invention.

[Explanation of symbols]

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

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Claims (5)

[Claims] 1. At least a rare earth element (L
n), Al, M (M is Ca and / or Sr), and Ti, and the composition formula is shown as aLn ₂ O _x .bAl ₂ O ₃ .cMO.dTiO ₂ (provided that 3 ≦ x ≦ 4). When the molar ratio a, b, c,
d is 0.056 ≦ a ≦ 0.214 0.056 ≦ b ≦ 0.214 0.286 ≦ c ≦ 0.500 0.230 <d <0.470 a + b + c + d = 1, and the crystallite diameter is A dielectric porcelain characterized by having a thickness of 100 to 1000Å. 2. The dielectric ceramic according to claim 1, wherein the rare earth element (Ln) is La and / or Nd. 3. The dielectric porcelain according to claim 1, which has a lattice strain of 0.3% or less. 4. Mn, W, Nb and Ta as metal elements
Dielectric according to at least one to one of _{MnO 2, WO 3, Nb 2} O 5 and Ta ₂ O ₅ in terms of a total 0.01 to 3 that it contains% by weight, characterized in claims 1 to 3 of Body porcelain. 5. A dielectric resonator comprising the dielectric ceramic according to any one of claims 1 to 4 arranged between a pair of input / output terminals and operated by electromagnetic field coupling. .