JPS6049147B2 - dielectric porcelain material - Google Patents

Description

[Detailed description of the invention] The present invention relates to dielectric ceramic materials, particularly BaO and Na.

O, Ni), O. , Br ( ) and Z1 ( Some attempts have been made to provide materials that can construct wave dielectric resonators. Conventionally, in the microwave region, dielectrics have been applied to impedance matching of microwave circuits, dielectric resonators, and the like. In recent years, in particular, as the technology for integrating microwave circuits has progressed, stabilization of the oscillator frequency, etc.
The use of dielectric ceramics with high dielectric constant, low loss, and low cost is being actively pursued to reduce the size of the device. Conventionally, these dielectric materials include BaO-TiO2-based porcelain, porcelain partially substituted with other elements, and TiO, whose dielectric constant changes negatively with temperature. In many cases, a combination of dielectric ceramic and dielectric ceramic having a positive dielectric constant that changes with temperature is used. However, these have large dielectric loss and
There are many practical problems, such as large variations in temperature changes in dielectric constant and too high stability of resonance frequency.

Applicant, for materials without these defects,
As a result of various studies, the general formula is xBa0.yNa.

0.593 in the composition represented by O-2Nb, O
≦X≦0.762, 0.04×0.13, 0.17
It has been discovered that porcelain having a composition within the range of 4 x O, 32 x + y + z = 1 can be made into an excellent dielectric microwave resonator (Japanese Patent Publication No. 59-48486). However, this has a considerably high temperature stability (Tf) of the resonant frequency and a low Q, so we conducted research to improve the stability and Q. The present invention is based on that result. The dielectric resonator material according to the present invention is
BaO, Na2O, and Nb2O5, plus Sr0
By adding ZrO2 and ZrO2, the temperature stability of the resonant frequency (Tf
).

Its characteristics are (1-w)(xBa0-yN
a. In the compositional formula 0・ZNb2q)+ wSr0−-ZrO2, 0.593×XO, 762, O, 04×y≦0.13, 0.174×z<00.32, xfy+
It is characterized by having a composition within the range of z=1, 0<w<, and 0.95.

The present invention will be explained below based on Examples.

First, starting materials of BacO3, Na, O, Nb2O5, SrCO3 and ZrO2 were weighed according to each composition and wet mixed with pure water in a ball mill equipped with an agate ball and lined with rubber.

This mixture was dried and then placed in air for 1200 min.
The mixture was calcined for 5 hours and then wet-pulverized in the ball mill. Take out the obtained crushed slurry from the ball mill,
After drying, the pressure is 700kg/Clt and the diameter is 25T!
It was molded into a disk shape of Rln and fired in air at a predetermined temperature for 2 hours to obtain porcelain having the composition shown in the table below. Then, a disk-shaped porcelain sample with a diameter of 57T0n and a thickness of 2 mm was cut out from each piece of porcelain, and used in a dielectric resonator for microwaves, and the resonant frequency was measured by the trap method. Resonant frequency (approximately 11GHz)
The dielectric constant (E) was measured from the and the diameter, and the unloaded Q (Qu) was measured using the band reflection method. Temperature stability of resonance frequency (
Tf) is calculated by placing each sample in a temperature bath and heating it from -30°C to +7°C.
This was determined by measuring the change in trap frequency due to a temperature change of 0°C. The results are shown in the table below. As is clear from the table, the dielectric ceramic material of the present invention has a large no-load Q, a relatively large dielectric constant, and is excellent in the temperature stability of the resonance frequency in the microwave region. I understand that.

Samples 6 and 7 with compositions outside the scope of the present invention did not sinter well into porcelain and did not have sufficient mechanical strength to be used as a dielectric resonator, and sample 12 had a dielectric constant Since the temperature change of the resonant frequency is large and the Q is low, it was excluded from the scope of the present invention.

Claims (1)

[Claims] 1 General formula (1-w) (_xBaO・_yNa_2O・
In the composition represented by _zNb_2O_5)+_wSrO・ZrO_2, 0.593≦x≦0.762, 0.
04≦y≦0.13, 0.174≦z≦0.32, x+
A dielectric ceramic material characterized by having a composition within the range of y+z=1 and 0<w≦0.95.