JPS58217465A - High frequency 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 The present invention relates to a high frequency dielectric ceramic composition having a high dielectric constant and a high 10Q value.

Recently, with the advancement of technology for high-frequency circuits that handle wavelengths less than a few digits, that is, microwaves and millimeter waves (hereinafter collectively referred to as microwaves), efforts have been made to miniaturize circuits.

Conventionally, this high-frequency circuit uses single-cavity antennas, but since these antennas are about the same size as the microwave wavelength, they are an obstacle to miniaturization (
^Ta. to solve this problem.

A method has been considered to shorten the wavelength itself, but one way to achieve this is to use dielectric ceramics.

For such materials, TiO2-based materials are often used, such as CaTi0. -MgTiO, -L
The resonator is constructed of dielectric ceramics such as a, 0j-2TiO, ..., BaO-TiO2. However, these materials do not have the characteristics required when used in microwaves, that is, It has a high dielectric constant, a high Q value, and the temperature change characteristics of the dielectric constant are stable °CLn
However, it is not possible to obtain sufficient results to satisfy all of the above requirements.

Therefore, it is an object of the present invention to provide a high frequency dielectric ceramic composition that eliminates the above-mentioned conventional drawbacks.

Another object of the present invention is to provide a high frequency dielectric ceramic composition having a high dielectric constant.

Furthermore, since this invention changes the composition ratio, H
It is an object of the present invention to provide a high frequency dielectric ceramic composition having a dielectric constant of PO, 11CL, -C and an arbitrary temperature change rate.

That is, the gist of this invention is that T"h22
~43wt%, zr0238~58wt4, SnO! 9
-26% by weight as a main component, and further contains NiO in an amount of 10i or less, and Ta, O, in an amount of 5% by weight or less.

The reason for limiting the composition to the above composition range is as follows.

That is, when Tie is less than 22% by weight, the dielectric constant (ε)
decreases, and when it exceeds 43% by weight, the temperature coefficient of dielectric constant (T
C) becomes too large on the plus side.

Also, ZrO, becomes less than 38 times tts, and in some cases 5
If it exceeds 8% by weight, the temperature coefficient (TC) of the dielectric constant becomes large on the positive side. Furthermore, if SnO is less than 9% by weight, the temperature coefficient of dielectric constant (TO) becomes too large on the positive side and Q decreases, and if it exceeds 26% by weight, the temperature coefficient of dielectric constant (TC) becomes too large on the negative side. That's too much.

Next, when NiO among the additives exceeds 10% by weight, Q decreases, and when Ta, O, exceeds 5% by weight, Q decreases. In particular, Ta, O, have the function of making crystal growth uniform, so they suppress the increase in lattice misalignment within the crystal, resulting in Q
It has the effect of improving.

Hereinafter, this invention will be explained in detail according to examples.

High purity Tie, ZrO as a raw material! ,SnO,,N
iO, Ta, 05 were weighed to obtain porcelain with the composition ratio shown in Table 1, and mixed for 16 hours, then dehydrated and dried. F/
It was molded into a disk with a diameter of 1211 and a thickness of 61 EI under a pressure of d. Subsequently, the molded product was fired for 6 hours at a temperature of 1560 tons in a natural atmosphere to obtain a C porcelain sample.

For each porcelain sample, the dielectric constant (ε) at 7GI (z), Q, and the temperature coefficient (TC) of the resonant frequency are listed.
The electrical characteristics of each were measured and the results are shown in Table 1.

Items marked with * in Table 1 are outside the scope of this invention.

Everything else is within the scope of this invention.

Table 1 The dielectric constant (ε) and Q values in Table 1 were measured by the dielectric resonance method. In addition, TC represents the temperature change rate of the resonant frequency (fo), and the measurement is from +25℃ to +85℃.
Measured over a temperature range of

The temperature change rate (TC(fo)) of the resonant frequency (f) was obtained from the following formula, and the temperature change rate (T(X) of the dielectric constant (ε))
ε)] and the coefficient of linear expansion of porcelain due to temperature change (α). TC(f)=J4'TC(t)-a
Further, when the crystal grain size and bending strength of sample number 13 were measured, the crystal grain size was 5 to 10 μm.

It has a bending strength of 1200 JCF/d, and by containing Ta, 06, a porcelain with a small crystal grain size and a high strength can be obtained.

Incidentally, since sintering was impossible for sample numbers 4 and 10, electrical characteristics were not measured.

As is clear from the above embodiments, according to the present invention,
When the temperature coefficient (TC) of the resonant frequency is 0, it becomes 1,
One with a Q value as large as 7,800 was obtained. In addition, by changing the composition ratio, a temperature coefficient (TC) of an arbitrary resonance frequency can be obtained centering on j5 NPO, so when incorporated into a high frequency circuit, the temperature compensation effect with other electronic components can be improved. You can have it. Therefore, it is possible to provide a high frequency dielectric ceramic composition useful for dielectric resonators, antennas, substrates, etc. used in the C1 high frequency region.

patent applicant Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] T1 (h 22-452-45% by weight 238-58% by weight. 8n0.9-26% by weight as the main component, with 10 times NiO, 11 or less times, and 5 times Ta2O). A high frequency dielectric ceramic composition comprising the following additives.