JPH10324566A - Dielectric ceramic composition, its production and dielectric resonator and dielectric filter using that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dielectric ceramic compsn. having a proper dielectric const., high unloaded Q and a small temp. coefft. of resonance frequency by constituting the compsn. of MgTi2 O5 , CoTiO5 or (MgCo)Ti2 O5 , etc. SOLUTION: Powders of MgO, CaO, MgTi2 O5 , CoTi2 O5 or (MgCo)Ti2 O5 , TiO2 , Nb2 O5 , Cr2 O3 , MnO2 , Fe2 O3 , NiO and Al2 O3 having <=1 μm particle size are mixed in a wet state to obtain a starting material. The starting material is fired in an oxygen atmosphere to obtain a dielectric ceramic compsn. The obtd. compsn. consists of a phase of MgTi2 O5 , CoTi2 O5 or (MgCo)Ti2 O5 as a solid solution of these and a phase of MgTi2 O5 and CaTiO5 or (MgCo)Ti2 O5 as a solid solution of these, and the compsn. is expressed by the general formula, (Mgx Cay Coz )n O-TiO2 ((x), (y), (z), (n) satisfy 0.87<=x<0.95, 0.05<=y<=0.09, 0<z<=0.04, 0.85<=n<1.00 and x+y+z=1.0). Thereby, decrease in the Q due to CaTiO3 can be prevented, and a resonator having small temp. dependence characteristics and high Q can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates in particular to microwaves,
The present invention relates to a dielectric ceramic composition used as a dielectric resonator in a high frequency region such as a millimeter wave, a method for manufacturing the same, and a dielectric resonator and a dielectric filter using the same.

[0002]

2. Description of the Related Art In recent years, dielectric components have been used for dielectric resonators, dielectric filters, and the like in communication devices utilizing electromagnetic waves in the microwave region, such as automobile telephones, mobile telephones, satellite broadcasting, and the like. In order to use a dielectric porcelain composition for such a dielectric component, in addition to having an appropriate dielectric constant suitable for an application or a device, low loss in a microwave region, and temperature change of a resonance frequency are required. Is small, that is, the temperature change of the dielectric constant is small. Conventionally, for example, Japanese Patent Publication No. Sho 63
Of JP -138605 MgTiO ₃ -CaTiO ₃ -N
d ₂ Ti ₂ O ₇ system, MgT disclosed in Japanese Patent Publication No. 6-92727
iO ₃ -CaTiO ₃ -Ta ₂ O ₅ systems are known.

[0003]

However, the above M
gTiO ₃ —CaTiO ₃ —Nd ₂ Ti ₂ O ₇ system, MgTi
The O ₃ —CaTiO ₃ —Ta ₂ O ₅ system does not have a sufficient Q value, and a dielectric having a higher Q value has been desired. Also

[0004]

[Outside 1]

[0005] In the case of a large resonator utilizing resonance, there is a disadvantage that the sintered body is easily reduced during firing in air, and the inside of the element becomes bronze and the Q value becomes low. I was For this reason, a special and complicated manufacturing process for further annealing after firing is required. In the case of application to a coaxial dielectric resonator or a strip line resonator in which an Ag or Cu electrode is formed directly on the surface of a dielectric ceramic, if the roughness of the dielectric surface is large, conductor loss due to the electrode increases and the Q value decreases. Therefore, in order to obtain the sufficient Q value of the dielectric porcelain in such an application,
It is important to minimize the conductor loss due to the electrodes, and a dielectric ceramic composition composed of fine crystal grains and having a small surface roughness has been desired.

An object of the present invention is to provide a dielectric ceramic composition having an appropriate dielectric constant, a high unloaded Q value, and a temperature coefficient of a small resonance frequency. is there.

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve this object
The dielectric ceramic composition of the present invention has a general formula (Mg _x
Ca_yCo_z)_nO-TiO_Two(However, x + y + z = 1.
0), x, y, z and n represent a molar ratio, and 0.87 ≦ x <0.95 0.05 ≦ y ≦ 0.090 0 <z ≦ 0.04 0.85 ≦ n < 1.00 is a dielectric porcelain composition.

With this configuration, the above object can be achieved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention
Is represented by the general formula (Mg_xCa_yCo_z)_nO-TiO
_Two(Where x + y + z = 1.0), and x, y,
z and n represent a molar ratio, and a dielectric porcelain in the range of 0.87 ≦ x <0.95 0.05 ≦ y ≦ 0.090 0 <z ≦ 0.04 0.85 ≦ n <1.00 The composition has a negative resonance frequency.
Temperature coefficient of MgTiO _ThreeHas a positive temperature coefficient of CaTiO_Three
To obtain a zero temperature characteristic is the temperature characteristic of the conventional material.
Improvement method but CaTiO_ThreeThe lack that Q value decreases with quantity
The solution is that some of Mg and Ca
Is replaced with Co and (MgCaCo) O
And TiO_TwoIs a disadvantage of conventional materials.
High Q value and low temperature coefficient
I found that I could stand. Also, depending on the composition ratio of the main component,
Therefore, while maintaining a high Q value, the temperature relationship between permittivity and resonance frequency
The number can be adjusted.

According to a second aspect of the present invention, there is provided the dielectric ceramic composition according to the first aspect, wherein the composition comprises MgTi ₂ O ₅ , CoTi ₂ O _5, or a (MgCo) Ti ₂ O ₅ phase in which these are dissolved. Mg
A dielectric porcelain composition comprising a TiO ₃ phase and a CaTiO ₃ phase or a (MgCa) TiO ₃ phase in which these are dissolved, and a solid solution of CoTi ₂ O ₅ or MgO having a positive temperature coefficient of resonance frequency (MgCo). ) by Ti ₂ O ₅ phase, to prevent the decrease in Q value due to the CaTiO ₃ conventional material by compensating for the negative temperature characteristic of MgTiO _3, it is possible to obtain a small temperature characteristic and a high Q value.

According to a third aspect of the present invention, niobium oxide is converted into Nb ₂ O ₅ as an auxiliary component in an amount of 0.1 part by weight with respect to 100 parts by weight of the dielectric porcelain composition according to the first or second aspect. 3
A dielectric porcelain composition containing not more than 0 parts by weight (excluding 0 parts by weight). By containing niobium oxide, the crystal grains of the porcelain become finer, and the roughness of the surface of the sintered porcelain becomes Becomes smaller. Therefore, the conductor loss of a coaxial resonator or a stripline resonator in which an electrode of Ag, Cu or the like is formed directly on the surface of the dielectric ceramic can be reduced, and a resonator having a high Q value can be obtained.

According to a fourth aspect of the present invention, there is provided the dielectric ceramic composition according to any one of the first, second and third aspects.
Cr, Mn, Fe, N
One or more oxides selected from i are Cr ₂ O ₃ , Mn
A dielectric ceramic composition containing 0.3 parts by weight or less (excluding 0 parts by weight) in terms of O ₂ , Fe ₂ O ₃ , and NiO. Can be adjusted to the side. For this reason, a high Q value is obtained because the CaTiO ₃ content, which lowers the Q value, can be reduced. In addition, it also has the effect of stabilizing the dielectric characteristics depending on the firing temperature, so that the characteristics during mass production are stabilized.

[0013] The invention according to claim 5 is the invention according to claims 1, 2, and 3.
3 parts or 4 and 100 parts by weight of the dielectric porcelain composition described in any one of the above, aluminum oxide as an auxiliary component is not more than 0.3 parts by weight in terms of Al ₂ O ₃ (however, 0 parts by weight) Is a dielectric ceramic composition contained in the range of (A.
Since the solid solution phase strengthens the bond between the particles and increases the mechanical strength, high reliability can be obtained against thermal shock, dropping, polishing for adjusting the frequency of the resonator, and the like. In addition, due to the fine porcelain surface, conductor loss such as a coaxial resonator and a stripline resonator can be reduced, and a resonator having a high Q value can be obtained.

The invention according to claim 6 is the invention according to claims 1, 2, and
As an impurity contained in the dielectric ceramic composition according to any one of 3, 4, and 5, Na is converted to Na ₂ O, and the content is 0.03 in 100 parts by weight of the dielectric ceramic composition.
It is a dielectric porcelain composition having a content in the range of not more than parts by weight, and excellent dielectric properties can be obtained in a range where the content of the impurity Na is limited.

The invention according to claim 7 is the invention according to claims 1, 2, and
As an impurity contained in the dielectric porcelain composition according to any one of 3, 4, and 5, K is converted into K ₂ O, and 0.03 in 100 parts by weight of the dielectric porcelain composition. It is a dielectric porcelain composition having a content of not more than parts by weight, and excellent dielectric properties can be obtained within a range where the content of impurity K is limited.

The invention described in claim 8 is the invention according to claims 1, 2, and
The dielectric porcelain composition described in any one of 3, 4 and 5 is prepared by using MgTi ₂ O ₅ , CoTi ₂ O ₅ or (MgC
o) This is a method for producing a dielectric porcelain composition produced using Ti ₂ O ₅ as a starting material. Since the porcelain is homogenized, it has an effect on a high Q value and finer crystal grains, and has a high Q value. A resonator can be obtained.

According to a ninth aspect of the present invention, the starting material according to the eighth aspect has a particle size of 1 μm or less, and the crystal grains of the porcelain can be made finer and more uniform. , The conductor loss of a resonator directly forming an electrode (for example, a coaxial resonator or a stripline resonator) is reduced, and a resonator having a high Q value can be obtained.

The invention described in claim 10 is the first invention.
A method for producing a dielectric ceramic composition according to any one of 2, 3, 4, and 5, wherein the dielectric ceramic composition is fired in an oxygen atmosphere. Uniform distribution has the effect of obtaining high reliability and a high Q value.

The invention described in claim 11 is the first invention.
A dielectric resonator using the dielectric ceramic composition described in any one of 2, 3, 4, and 5, which has a high dielectric Q value and a fine porcelain surface. The element in a hollow container made of

[0020]

[Outside 2]

A high Q value can be obtained even in the case of a resonator utilizing resonance, or in the case of a coaxial resonator or a stripline resonator in which electrodes are formed directly on porcelain.

According to a twelfth aspect of the present invention, there is provided a dielectric filter including the dielectric resonator according to the eleventh aspect, wherein the insertion loss of the filter is reduced by using a dielectric resonator having a high Q value. it can.

[0023]

【Example】

Embodiment 1 Hereinafter, a first embodiment of the present invention will be described in detail.

The starting material is chemically pure and has a particle size of 1
μm or less of MgO, CaO, MgTi ₂ O ₅ , CoTi _{2
O 5, TiO 2, Nb 2} O 5, Cr 2 O 3, MnO 2, Fe 2 O
₃ , NiO and Al ₂ O ₃ powders were weighed so as to have a predetermined composition ratio, and these powders were put into a polyethylene ball mill, and stabilized zirconia balls and ethanol were added and wet-mixed for about 20 hours. If the particle size of the starting material used here is larger than 1 μm, the crystal grain size of the final sintered ceramic becomes large, or abnormal grain growth occurs, so that the conductor loss of the coaxial resonator or strip line increases and the resonator becomes The problem arises that the Q value of is low. Therefore, the particle size is 1μ
The use of starting materials less than m is essential. After wet mixing, the mixture was dried, and the dried powder was placed in a high alumina crucible and calcined in air at 800 to 1100 ° C. for 2 hours.
Next, this calcined powder was put together with ethanol in the same ball mill as at the time of mixing, wet-pulverized for about 20 hours, and then dried. Next, an organic binder was added to the pulverized powder, mixed homogeneously, and sieved through a 32 mesh sieve.
Using a mold and a hydraulic press, molding was performed at a molding pressure of ² ton / cm ² to a diameter of 17 mm and a thickness of 6 to 8 mm. Next, the molded body was put in an alumina sheath, and in the air at 1200 to 1200 m.
Baking at a baking temperature of 1400 ° C. for 2 to 50 hours, (Table 1)
Was obtained.

[0025]

[Table 1]

The characteristics of the sample shown in this example are the characteristics when fired in air, and when fired in an oxygen atmosphere, the Q value is particularly improved by about 20% as compared with the air fired. have. By firing the porcelain composition of the present invention in an oxygen atmosphere, homogeneous sintering of the porcelain can be achieved, high reliability can be obtained, and a resonator having a high Q value can be obtained. Next, both sides of the obtained sintered body were polished, and the dielectric characteristics in a microwave were measured. The measurement is performed by the dielectric resonator method, and the dielectric constant (ε _r ), the Q · f product,
The temperature coefficient τ _f (ppm / ° C.) of the resonance frequency was calculated.
In the measurement of the dielectric constant and the Q value, the resonance frequency is 5.0 to 5.0.
It was 6.5 GHz. Temperature coefficient of resonance frequency (τ _f )
Was measured in the range of −25 to 85 ° C.

The above measurement results are shown in Table 1 for each sample number of 1 to 31. In Table 1, those marked with * are comparative examples outside the scope of the claims of the present invention.

The reasons for limiting the composition range of the dielectric ceramic composition of the present invention will be described with reference to (Table 1) and (FIG. 1).

As is clear from Table 1 and FIG.
When the molar ratio (y) of CaO is more than 0.09 (region
A) is the temperature coefficient of the resonance frequency
(Τ_f) Increases to the positive side and becomes impractical. And
The molar ratio (y) of CaO is less than 0.05 (region C)
Is the temperature coefficient of the resonance frequency (τ_f) Increases to the negative side.
Further, when the molar ratio (z) of CoO is more than 0.04,
(Region B) is excluded from the scope of the present invention because the Q value decreases.
did. And (MgCaCo)_nO and TiO_TwoOf the ratio
When (n) is smaller than 1.0, the improvement of the Q value and the temperature characteristics are improved.
Has the effect of shifting the characteristic to the positive side,
The content of CaO to be added can be reduced. But,
If (n) is smaller than 0.85, the Q value will decrease.
And the range of (n) is limited. These high Q values and small
As a result of analyzing the sample with temperature characteristics by X-ray diffraction, the resonance frequency
CoTi whose temperature coefficient is_TwoO_Five(Mg also dissolved) phase
It was found that the effect was due to generation of. In other words, the temperature
CoTi with a very large number_TwoO_Five(Mg is also a solid solution)
CaTiO is used to adjust the properties_ThreeJust adjusted
Higher Q value can be obtained by comparing with the same temperature coefficient than the case
You. At this time, other than MgTiO _Three, CaTiO_ThreeIs generated
Was. Therefore, as in the present embodiment, Mg, Co saw
To MgTi_TwoO_Five, CoTi_TwoO_FiveUse as starting material
Indispensable for both high Q value and small temperature coefficient
CoTi, the crystalline phase of_TwoO_Five(Mg is also a solid solution)
It is possible to generate it stably. And (n) is 1
Above is CoTi_TwoO_FiveNo phase is formed and MgTiO_Three,
CaTiO_ThreeIn a mixed phase (solid solution of Co)
There is no improvement effect and the Q value is low. (N)
If the value is smaller than 0.85, the Q value decreases and the temperature characteristic decreases.
Since it deteriorated, it was excluded from the scope of the present invention. Like this
This limits the composition range of the main component. Next, the subcomponent
The effect of adding is described. Nb_TwoO_FiveAddition of porcelain
It is effective in reducing the crystal grain size. 7 to 10 when not added
Crystal having a crystal particle diameter of 3 to 6 μm by adding Nb
Sintering can be performed uniformly with the particle size. Ag directly on porcelain
Coaxial resonators and strip lines forming Cu and Cu electrodes
In the case of a vibrator, conductor loss due to electrodes is large. This is low loss
To reduce the surface roughness of the electrodes, reduce the roughness of the porcelain surface.
It is necessary to reduce the resistance. Nb addition of porcelain surface
Diminishing the crystal grain size can reduce conductor loss, so dielectric
High Q value of body porcelain and high Q value (low loss) resonance
A vessel is obtained. However, excessive addition causes a decrease in the Q value.
Therefore, the amount of addition is limited to 0.3 parts by weight or less. Ma
Cr_TwoO_Three, MnO_Two, Fe_TwoO_Three, NiO added
In this case, the temperature coefficient of the resonance frequency (τ_f) Changes slightly positive
Tend to. Subtle temperature characteristics by using this
Can be adjusted, and the CaO content that lowers the Q value
(Τ_fHigh Q because the positive component of the
There is also an effect that a value can be obtained. However, the additive amount of the subcomponent is 0.
If it exceeds 30% by weight, the fQ product will decrease.
It was excluded from the scope of the present invention. And Al_TwoO_ThreeAddition of magnetic
This has the effect of miniaturizing the vessel and improving the mechanical strength. porcelain
The same effect as Nb can be obtained for the effect of miniaturization of
You. On the other hand, regarding mechanical strength, Al_TwoO_ThreeDue to the high strength of
Therefore, the solid solution phase of the main component of the grain boundary and Al is fine crystal grains.
Since the bonding force between the children is strengthened, the mechanical strength is improved.
For example, when Al is not added, about 1.2 to 1.5 t / cm
^TwoFlexural strength of 1.8 to 1.8 when Al is added.
2.2t / cm^TwoHigh strength can be obtained. Obedience
The reliability of the resonator against thermal shock,
You. Polishing and processing of elements such as frequency adjustment in the manufacturing process
Also, there is an effect of preventing chipping or cracking of the element due to the above. But,
When the amount added is more than 0.30 parts by weight, the Q value decreases.
It was excluded from the scope of the present invention. Like this
Therefore, the composition range of the present invention, the subcomponents and the amount added are limited.
It is. From the above, some examples of the present invention include, for example, ε
_rIs 21, the Q · f product is 71430, and the temperature
Number (τ_f) Is +2.5 ppm / ° C excellent microwave induction
There is a composition having electrical characteristics (Sample 5).

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described in detail.

The composition of Sample 5 of Example 1 was similarly blended,
After mixing, calcining, pulverizing, and sizing, 1-2 t / c into a cylindrical shape having an outer diameter of 35 mm, an inner diameter of 7.6 mm, and a height of 22 mm.
Molding was performed at a molding pressure of m ² . Then, at a temperature of 1200 to 1400 ° C. in air and an oxygen atmosphere, 2 to 50
The firing was performed for a time. Then place the sample on the alumina support in the Ag-plated cavity

[0032]

[Outside 3]

The resonance frequency and Q value were measured. The porcelain density was also measured by the Archimedes method.

The results are shown in Table 2 for each sample number of 32-33.

[0035]

[Table 2]

As is evident from Table 2, the Q.f product of the sample fired in the oxygen atmosphere is about 20% higher than that of the comparative example. Also, the embodiment has a lower resonance frequency. This is a result of an increase in the dielectric constant due to the high density of the porcelain of the sample. However, firing in an oxygen atmosphere enables uniform sintering even inside the element. In the sample of the comparative example fired in the air, the density of the porcelain differs between the inside and outside of the element, and the inside is particularly porous. High reliability is required for base station filters, which are the main applications of large-sized elements. However, if the elements are not uniform, the reliability (thermal shock, moisture resistance, etc.) will be reduced, so a uniform and highly reliable element will be required. Is required.

As described above, by firing a large-sized element in an oxygen atmosphere, a resonator having a highly reliable Q value can be provided.

(Embodiment 3) Hereinafter, a third embodiment of the present invention will be described in detail.

As starting materials, those having high chemical purity (purity 99.99% or more) and industrial materials (purity 98.0-9)
9.9%) using MgO, CaO, MgTi ₂ O ₅ ,
CoTi ₂ O ₅ and TiO ₂ powder were weighed so as to have a predetermined composition ratio, and then a sintered body was prepared in the same manner as in Example 1, and the microwave dielectric properties were evaluated. The content of impurities contained in each sintered body was analyzed by fluorescent X-ray analysis, and the composition of ceramics and the content of impurities were determined using a sample whose composition and Na ₂ O and K ₂ O contents were known in advance as a standard sample. The amount was determined.
Dielectric properties of each sample and impurities Na ₂ O and K _{2 in} porcelain
The content of O is shown in (Table 3).

[0040]

[Table 3]

As is clear from Table 3, we have trace amounts of impurities such as Na ₂ O and K ₂ contained in the starting materials.
It has been found that the content of O has a great influence on the dielectric properties of the final sintered ceramic. When the contents of Na ₂ O and K ₂ O are more than 0.03 parts by weight, the f · Q product sharply decreases. It also changes the dielectric constant and temperature characteristics. Further, abnormal grain growth occurs in the sintered ceramics, and the strength of the ceramics also decreases. In particular, in the case of application to a base station filter, high reliability such as heat generation and environmental resistance of the element is required as well as low loss. Therefore, in particular, Na ₂ O and K _{2 in} porcelain
The pure water, the dispersant, the binder, and the like used in the use of the starting materials and in the production process of the dielectric porcelain do not contain Na or K so that the content of O is 0.03 parts by weight or less. By setting the impurity content within the range of the invention, a high fQ product and high reliability can be obtained. As described above, by adopting the starting material and the production process in which the contents of Na and K are controlled within the scope of the present invention,
Dielectric characteristics of a dielectric ceramic having a high Q value and a high reliability, which were sensitive or unstable to a raw material lot or a manufacturing process of a starting material, can be stabilized with good reproducibility.

[0042]

The present invention as described above, according to the present invention is, as a general formula _{(Mg x Ca y Co z)} n O-TiO 2 ( provided that, x + y +
z = 1.0), x, y, z, and n represent a molar ratio, and 0.87 ≦ x <0.95 0.05 ≦ y ≦ 0.090 0 <z ≦ 0.040. A dielectric ceramic composition in the range of 85 ≦ n <1.00, in which a part of Mg and Ca is replaced with Co and limited at the same time (MgCaC
o) By setting the molar ratio of O to TiO ₂ , a decrease in the Q value, which is a disadvantage of the conventional material, can be prevented, and both a high Q value and a small temperature coefficient can be achieved. Also, due to the composition ratio of the main component, a high Q
The temperature coefficient of the dielectric constant and the resonance frequency can be adjusted while maintaining the values.

Further, since the surface of the dielectric porcelain is composed of fine crystal grains, for example, when a coaxial dielectric resonator for directly forming an electrode on an element is formed using this dielectric porcelain composition, the electrode portion is formed. Since the conductor loss can be reduced, the Q value of the resonator can be increased. Further, since the bonding strength between the element body and the electrode can be increased, a highly reliable dielectric resonator can be obtained.

In addition, the microwave dielectric resonator and the temperature compensating ceramic capacitor using the dielectric ceramic composition of the present invention greatly contribute to miniaturization and high performance of communication equipment and electric equipment. There is a large industrial use value.

[Brief description of the drawings]

FIG. 1 is a view showing a composition range of a main component of a dielectric ceramic composition of the present invention.

Claims (12)

[Claims] 1. A as a general formula _{(Mg x Ca y Co z)} n O-
TiO ₂ (where x + y + z = 1.0)
x, y, z and n represent a molar ratio, and in the range of 0.87 ≦ x <0.95 0.05 ≦ y ≦ 0.090 0 <z ≦ 0.04 0.85 ≦ n <1.00 Certain dielectric porcelain compositions. 2. The dielectric ceramic composition according to claim 1,
MgTi ₂ O ₅ , CoTi ₂ O ₅ or (MgCo) Ti ₂ O ₅ phase in which these are dissolved, MgTiO ₃ phase and CaT
A dielectric ceramic composition comprising an TiO ₃ phase or a (MgCa) TiO ₃ phase in which these are dissolved. 3. Niobium oxide is converted to Nb ₂ O ₅ in an amount of 0.3 parts by weight or less (provided that 0 parts by weight is used) based on 100 parts by weight of the dielectric porcelain composition according to claim 1 or 2. except)
The dielectric ceramic composition contained in the range of. 4. The composition according to claim 1, wherein 100 parts by weight of the dielectric porcelain composition is Cr,
One or more oxides selected from Mn, Fe and Ni are Cr
A dielectric ceramic composition containing not more than 0.3 parts by weight (excluding 0 parts by weight) in terms of ₂ O ₃ , MnO ₂ , Fe ₂ O ₃ , and NiO. 5. The dielectric ceramic composition according to claim 1, 2, 3, or 4, wherein A is 100 parts by weight.
A dielectric ceramic composition contained in a range of 0.3 parts by weight or less (excluding 0 parts by weight) in terms of l ₂ O ₃ . 6. The dielectric material according to claim 1, wherein Na is converted to Na ₂ O as an impurity contained in the dielectric porcelain composition according to any one of claims 1, 2, 3, 4, and 5. A dielectric porcelain composition having a content of 0.03 parts by weight or less based on 100 parts by weight of the porcelain composition. 7. The dielectric material according to claim 1, wherein K is converted to K ₂ O as an impurity contained in the dielectric porcelain composition according to any one of claims 1, 2, 3, 4, and 5. A dielectric porcelain composition having a content of 0.03 parts by weight or less based on 100 parts by weight of the porcelain composition. 8. The dielectric porcelain composition according to claim 1, wherein the composition is MgTi ₂ O ₅ ,
A method for producing a dielectric ceramic composition using CoTi ₂ O ₅ or (MgCo) Ti ₂ O ₅ as a starting material. 9. The starting material according to claim 8, which has a particle size of 1 μm.
A method for producing a dielectric porcelain composition using: 10. A method for producing a dielectric ceramic composition according to claim 1, wherein the dielectric ceramic composition is fired in an oxygen atmosphere. 11. A dielectric resonator using the dielectric porcelain composition according to any one of claims 1, 2, 3, 4 and 5. 12. A dielectric filter comprising the dielectric resonator according to claim 11.