JP2624576B2 - High frequency dielectric porcelain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to realize a practically sufficient Q value and a small and stable temperature characteristic when used in the microwave frequency range, exhibiting a very wide range of relative permittivity in the same composition system. A high frequency dielectric ceramic.

[0002]

2. Description of the Related Art High-frequency dielectric ceramics are widely applied as resonators, filters, substrates, and the like to portable radios, satellite broadcasts, microwave integrated circuits, and the like, and have improved filter characteristics, frequency stability, and devices and circuits. It has greatly contributed to the miniaturization of. Devices using such a dielectric are used at various frequencies, and the required relative permittivity also changes depending on the frequency used. Also,
The required dielectric properties vary depending on the type of device or its type. Therefore, when designing a wide variety of dielectric devices, if there are materials with similar dielectric, electrical or physical stability such as insulation resistance, mechanical strength, and water absorption, but different dielectric properties, This is extremely advantageous because changes in design factors are reduced.
Desirable properties of such a dielectric include a wide range of relative permittivity, similar properties other than dielectric properties, low dielectric loss, and excellent temperature stability of the resonance frequency. I can give things.

[0003] In order to satisfy the above-mentioned characteristics, particularly the characteristics shown in (1), it is considered necessary that the basic compositions are similar. However, a dielectric having such characteristics cannot be found in the past. As a high-frequency usable dielectric material having a similar basic composition, for example, reference is made to J. of Am. Cera
m. Soc., 58 [9-10], 418 (1975), BaTi ₄ O ₉ , Ba ₂ Ti
₉ O ₂₀ (BaTi _4.5 O ₁₀ ).

[0004]

In the dielectric ceramic material for high frequency, the relative dielectric constant over a wide range generally has the same basic composition (the characteristics other than the dielectric characteristics are similar).
Simultaneous realization of low dielectric loss and small and stable temperature counting is extremely difficult. That is, the relative permittivity of the above-mentioned conventional dielectric ceramics is about 40, and the relative permittivity region that can be covered by the similar basic composition is extremely small.

The present invention has been made to solve such a problem, and has a wide relative dielectric constant ranging from 20 to 60 in the microwave region while maintaining a similar basic composition.
It is another object of the present invention to provide a high-frequency dielectric porcelain which realizes a sufficiently high Q value and a stable and small temperature coefficient for practical use, and facilitates device development.

[0006]

Means for Solving the Problems] high-frequency dielectric ceramic of the present invention have the general formula: xSrO · yCaO · z [( 1-m) TiO 2 · m / 2 {TaO 5/2 · (1-
n) GaO _3/2 · nGdO _3/2 }] where 0.42 ≦ x ≦ 0.54 (or 0.06 ≦ x ≦ 0.18) 0.06 ≦ y ≦ 0.18 (or 0.42 ≦ y ≦ 0.54) z = 0.40 0.05 ≦ m ≦ 0.70 It is represented by 0.00 ≦ n ≦ 1.00 x + y = 0.6, and further contains Mn ₂ O ₃ in an amount of 3% by weight or less based on the total amount.

[0007]

According to the present invention, by using the above-mentioned composition,
The intended purpose can be achieved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

The dielectric porcelain of the embodiment of the present invention is obtained by mixing and sintering strontium carbonate, calcium carbonate, titanium oxide, tantalum oxide, gallium oxide, gadolinium oxide, and manganese oxide at a predetermined ratio. , general formula: xSrO · yCaO · z [( 1-m) TiO 2 · m / 2 {TaO 5/2 · (1-
n) GaO _3/2 · nGdO _3/2 }] where 0.42 ≦ x ≦ 0.54 (or 0.06 ≦ x ≦ 0.18) 0.06 ≦ y ≦ 0.18 (or 0.42 ≦ y ≦ 0.54) z = 0.40 0.05 ≦ m ≦ 0.70 It is represented by 0.00 ≦ n ≦ 1.00 x + y = 0.6, and further contains Mn ₂ O ₃ in an amount of 3% by weight or less based on the total amount. The limit amount is determined comprehensively for various reasons, and it is not easy to unambiguously define the limit amount.Also, there are cases where the limit amount varies depending on the processing conditions at the time of production, etc. Can be shown. Outside the composition range, a decrease in the Q value of x <0.06, x> 0.54 is observed. When 0.18 <x <0.42, the relative permittivity increases, but both the Q value and the temperature coefficient of the relative permittivity deteriorate. Further, when the value of m is out of the range defined in the claims, the temperature coefficient of the relative permittivity deteriorates. In these composition ranges, the dielectric properties deteriorate, making it difficult to use as an industrial material. The addition of Mn slightly changes the temperature coefficient to the positive side, but adding more than 3% by weight causes a decrease in the Q value.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.

Examples and Comparative Examples Commercially available powders of strontium carbonate, calcium carbonate, titanium oxide, tantalum oxide, gallium oxide, gadolinium oxide, and manganese oxide were weighed to have the composition shown in Table 1, and zirconia was prepared. ball,
The mixture was charged into a nylon ball mill pot together with ethyl alcohol and mixed for 16 hours. Thereafter, the mixed powder was evaporated to dryness at 100 ° C. for 3 hours, pulverized, and then calcined at 1100 ° C. for 3 hours to obtain a compound powder. Further, the compound powder was pulverized by a ball mill under the same conditions as above and dried. 700-800
The pressure of kg / cm ^2, and molded into a diameter of 16 mm, cylindrical as height 12 mm, the molded body in an oxygen atmosphere, from 1400 to 1,550 ° C.
Then, sintering was performed for 4 hours to obtain a dielectric ceramic according to an example of the present invention.

A dielectric ceramic of a comparative example was obtained in the same manner as in the example except that sintering was performed in an air atmosphere.

After each of the porcelains obtained as described above is machined to a predetermined size, dielectric properties (relative permittivity and Q value) are measured at 6 GHz by a dielectric resonator method.
Shown in Table 1 shows the relative permittivity, the Q value, and the temperature coefficient of the relative permittivity for each composition. From Table 1, it is clear that the dielectric porcelain of the embodiment of the present invention can be used even in the microwave region.
It can be seen that the dielectric constant has a wide range of up to 60 units, a sufficiently high Q value, and a small and stable temperature coefficient.

[0014]

[Table 1]

[0015]

As described above, the present invention provides a compound of the general formula: xSrO.yCaO.z [(1-m) TiO ₂ .m / 2 {TaO _5/2. (1-
n) GaO _3/2 · nGdO _3/2 }] where 0.42 ≦ x ≦ 0.54 (or 0.06 ≦ x ≦ 0.18) 0.06 ≦ y ≦ 0.18 (or 0.42 ≦ y ≦ 0.54) z = 0.40 0.05 ≦ m ≦ 0.70 0.00 ≦ n ≦ 1.00 x + y = 0.6 Further, Mn ₂ O ₃ is added and contained in an amount of 3% by weight or less of the total amount, so that even in the microwave region,
It is possible to obtain a high frequency dielectric ceramic having a wide range of relative dielectric constants of up to 60 units and a sufficiently high Q value and a small and stable temperature coefficient for practical use. For example, by using the dielectric porcelain of the present invention, it is possible to improve the performance of microwave application components such as a microwave IC substrate and to design devices and the like.

Claims (2)

(57) [Claims] [Claim 1] General formula: xSrO.yCaO.z [(1-m) TiO ₂ .m / 2
{TaO _5/2・ (1-n) GaO _3/2・ nGdO _3/2 }] where 0.42 ≦ x ≦ 0.54 0.06 ≦ y ≦ 0.18z = 0.40 0.05 ≦ m ≦ 0.70 0.00 ≦ n ≦ 1.00 x + A dielectric ceramic for high frequencies, represented by y = 0.6 and further containing Mn ₂ O ₃ in an amount of 3% by weight or less. 2. The general formula: xSrO.yCaO.z [(1-m) TiO ₂ .m / 2
{TaO _5/2・ (1-n) GaO _3/2・ nGdO _3/2 }] where 0.06 ≦ x ≦ 0.18 0.42 ≦ y ≦ 0.54z = 0.40 0.05 ≦ m ≦ 0.70 0.00 ≦ n ≦ 1.00 x + A dielectric ceramic for high frequencies, represented by y = 0.6 and further containing Mn ₂ O ₃ in an amount of 3% by weight or less.