JPH05174627A - High frequency dielectric porcelain composition - Google Patents

Abstract

PURPOSE:To provide a dielectric porcelain composition of TiO2 system used at high frequency such that the temperature stability of its resonance frequency is excellent while containing high specific dielectric constant and no-load Q. CONSTITUTION:A dielectric porcelain composition includes Al2O3 of 0.005-0.05mol in TiO2 of 0.3995-0.395mol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency dielectric ceramic composition used for a dielectric resonator or the like, and more particularly to a dielectric ceramic composition containing TiO ₂ as a main component.

[0002]

2. Description of the Related Art A material having a high relative dielectric constant is desired in order to reduce the size of a coaxial dielectric resonator using a TEM mode, a dielectric substrate of a stripline filter, or the like. High T around 100
The iO ₂ porcelain is known.

[0003]

The TiO ₂ porcelain has a high relative dielectric constant, but has practical problems such as lack of temperature stability of the resonance frequency.

[0004]

SUMMARY OF THE INVENTION The present invention is based on TiO ₂ .
By containing 005 to 0.05 mol of Al ₂ O ₃ , the temperature stability of the resonance frequency can be improved.

[0005]

EXAMPLES The present invention will be described below with reference to examples. 99.98% pure TiO ₂ powder and 99.995% pure A
Using l ₂ O ₃ powder, these were weighed and mixed so that the composition ratios shown in Table 1 were obtained, an appropriate amount of organic binder and water were added, and the mixture was pulverized with an alumina ball and granulated by spray drying to obtain The obtained powder was pressure-molded at a pressure of 1 ton / cm ² to obtain a cylindrical molded body having a diameter of 19 mm and a thickness of 8 mm. Subsequently, the compact was fired in air at a temperature of 1350 ° C. for 4 hours, and then finally polished into a cylindrical shape having a diameter of about 16 mm and a height of about 8 mm, which was used as a sample for a parallel conductor plate type dielectric cylinder resonator method (TE). the resonance frequency 2 by ₀₁₁ mode).
Table 1 shows the results obtained by measuring the relative permittivity ε, the unloaded Q, and the temperature coefficient τ f (+ 20 ° C to + 80 ° C) of the resonance frequency at 7 GHz.
Shown in.

[0006]

[Table 1]

As is clear from Table 1, 0.005
~ T of the present invention comprising ~ 0.05 mol Al ₂ O _3.
As shown in Sample Nos. 2 to 6, the iO ₂ -based dielectric ceramic composition is slightly lower in relative dielectric constant and unloaded Q than the conventional composition composed of TiO ₂ alone containing no Al ₂ O _3. However, relative permittivity 55-97, no load Q1000-1
It shows a high value of 900 and the temperature coefficient of resonance frequency τf
Was smaller than the conventional composition consisting of TiO ₂ alone containing no Al ₂ O ₃ and showed a stable practical range value of +10 to +345 ppm / ° C.

In the composition of the present invention, the content of Al ₂ O ₃ with respect to TiO ₂ is limited to within the range of 0.005 to 0.05 mol. If the amount exceeds 0.05 mol, the relative dielectric constant and the unloaded Q, which are other properties, are significantly lowered, and a practical level value cannot be obtained.

[0009]

As described above, the TiO ₂ -based dielectric ceramic according to the present invention is excellent in temperature stability of resonance frequency, and has a relative dielectric constant,
Since the unloaded Q is high, it can be effectively used as a material for a coaxial resonator used in the microwave region.

Claims (1)

[Claims] 1. A high frequency dielectric ceramic composition comprising 0.995 to 0.95 mol of TiO ₂ and 0.005 to 0.05 mol of Al ₂ O ₃ .