JPS6172675A - Dielectric ceramic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a dielectric ceramic composition, which has a dielectric constant of 1%, a high no-load Q, and stable temperature characteristics. It is related to.

[Conventional technology]

Dielectric ceramics have been applied to dielectric resonators and impedance matching in microwave circuits. In recent years, with the advancement of technology that applies microwave circuits, especially for satellite broadcasting and car phones, the use of dielectric ceramics with high dielectric constant and low loss has become necessary for stabilizing the frequency of 9 oscillators and downsizing dielectric filters. has been actively carried out.

Conventionally, these dielectric elements include (ZrSn)Ti.
O4, MgTi0. - Tie-based materials such as CaTiOs have been widely used.

[Problem that the invention seeks to solve]

However, these dielectrics have large dielectric loss and poor stability of temperature characteristics of resonance frequency.

Moreover, there were many problems in practical use, such as large variations.

[Means for solving problems]

In order to solve all the problems mentioned above.

In the present invention, 45.5 to 63.0% by weight as BaO
.

0.1 to 12.0% by weight as Coo, 0.1 to 7.0% by weight as MgO, 0.1 to 48 as Ta*Os
．． 0% by weight.

The present invention provides a dielectric ceramic composition containing Nb, O, () in an amount of 1 to 35.0% by weight.

As a result, as will be described later, it is possible to provide a material with a high dielectric constant, a high no-load Q value, and excellent temperature stability of the resonance frequency.

〔Example〕

The present invention will be explained based on examples.

As starting materials, commercially available BaC01, Coo, Mg
CO5゜'ra, o, and Nb20. After final sintering, weighed t so that it would have the composition shown in Table 1, and milled it in a ball mill for 2
Time mixing was carried out at 0:00. This mixed material is dehydrated and dried,
It was calcined at 1000° C. to 1200° C. for about 2 hours, and then the calcined body was coarsely ground and further wet-pulverized in a ball mill. Then dehydrate this crushed mud.

Dry. An appropriate amount of a binder was added to the thus obtained powder, which was then granulated, pressure-molded into a cylindrical shape with a diameter of 12.37 W and a height of 7 mm, and fired at 1350° C. to 1600° C. for about 2 hours.

,, Next, the dielectric porcelain obtained as described above was cut into a diameter of 1
It was processed to a size of 0 mm and 5 mm high, and the dielectric constants ε and Q at 25° C. and 8 GHz were determined. The measurement was carried out using the TEOII mode of a resonator constructed by sandwiching the cylindrical dielectric material between two parallel metal plates. Further, the resonant frequency temperature coefficient TCf was determined from the change in the resonant frequency when the temperature changes from -40°C to +80°C. In this way, the values shown in Table 1 were obtained.

As is clear from Table 1, the reasons for limiting the composition range in the present invention are as follows.

That is, BaO is less than 45.5% by weight or 63.0% by weight.
If it exceeds % by weight, the sinterability will be poor and the Q will be lowered.

In addition, when CoO is less than 0.1% by weight, Q is low (,12,0
If it exceeds % by weight, the temperature coefficient TCf will be too large on the negative side.

When MgO is less than 0.1% by weight, Q is low (,7.0% by weight)
If it exceeds , the temperature coefficient TCf is too large.

Furthermore, Ta, 0. is less than 0.1% by weight, Q is low.

If it exceeds 48.0% by weight, sinterability will deteriorate.

If NbtOs is less than 0.1% by weight, the Q will be low and the sinterability will be poor, and if it exceeds 35.0% by weight, the temperature coefficient TC
f is too dog-like.

When the dielectric ceramic thus obtained was used as a dielectric resonator for frequency stabilization of a local oscillator of a BS converter in the 12 GHz band, good characteristics were obtained.

The dielectric ceramic composition of the present invention has a high Q value not only in the microwave band but also in low frequencies around IMH2, has a high dielectric constant, and has a small temperature coefficient, so it can be used as a material for ceramic capacitors. However, it was confirmed that it had good characteristics.

〔Effect of the invention〕

The present invention has a high dielectric constant and a large no-load Q.

Furthermore, it is possible to provide a dielectric ceramic composition with excellent temperature stability of resonance frequency.

Claims (1)

[Claims] An oxide containing Ba, Co, Mg, Ta, and Nb, 45.5 to 63.0% by weight as BaO, 0.1 to 12.0% by weight as CoO, and 0.1 to 7% as MgO.
．． 0% by weight, 0.1 to 48.0% by weight as Ta_2O_5, and 0.1 to 35.0% by weight as Nb_2O_5.