JPS5949648B2 - Materials for dielectric resonators - Google Patents

Description

[Detailed description of the invention] The present invention relates to materials for dielectric resonators, particularly BaO and ZnO.

This relates to a dielectric resonator material composed of Ta2o5, CaO, and ZrO2 components, and constitutes a dielectric resonator for microwaves that has a large dielectric constant ε and no-load Q, and has excellent temperature stability γf of the resonance frequency. The aim is to provide materials that can be used. Conventionally, in the microwave region, dielectrics have been applied to impedance matching of microwave circuits, dielectric resonators, and the like.

In recent years, especially as the integration technology of microwave circuits has progressed, there has been an active use of high dielectric constant, low loss, and low cost dielectric ceramics for miniaturization, such as stabilizing the frequency of oscillators. is being advanced. Conventionally, these dielectric materials include BaO-Ti0 ceramics, porcelains in which some of them are replaced with other elements, and TiO2, which has a negative dielectric constant that changes with temperature, and TiO2, which has a positive dielectric constant that changes with temperature. In many cases, a combination of dielectric porcelain and porcelain is used. but,
These have many practical problems, such as large dielectric loss, large variations in temperature change in dielectric constant, and too high stability of resonance frequency.

The applicant conducted research to obtain a material free of these drawbacks, and in the composition represented by the general formula xBa0-yZn0-2Ta205, 0.5≦x≦0.75, 0.
1≦y≦0.3, 0.1≦z≦0.3 (however, x+y+
It has been discovered that porcelain with a composition within the range of
No. 10275).

However, the temperature stability γf of the resonant frequency is quite large, and research has been carried out to improve this stability. The present invention is based on that result. The dielectric resonator material according to the present invention includes BaO, Zn
By further adding CaO and ZrO2 to O and Ta2O5, the temperature stability γf of the resonant frequency can be increased without reducing the no-load Q and the dielectric constant. Its characteristics are (1-
w) (xBa0-yZn0-2Ta2o5)+wcao
-2ro2 composition formula, 0.5≦X≦0.75
, 0.1≦y≦0.3, 0.1≦z≦0.3, x+y+
It is characterized by having a composition within the range of z=1 and 0<w≦0.9. Hereinafter, the present invention will be explained based on Examples.

First, starting materials of BaCO3, 2no, Ta2O5, caco3, 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. Let this mixture dry and then
After calcining in air at 1200'C for 5 hours, it was wet-pulverized in the ball mill. After taking out the obtained crushed slurry from the ball mill and drying it, the pressure was 700k9.
/Cwi to form a disk shape of 25-diameter and fired in air at a temperature within the range of 1460 to 1360'C for 2 hours to obtain porcelain having the composition shown in the table below. after that,
A disc-shaped porcelain sample with dimensions of 5-diameter and 2-thickness was cut out from each piece of porcelain, and used in a microwave dielectric resonator to measure the resonant frequency using the trap method. 11 GHz) and the diameter, and the no-load Q (Qu) was measured by the band reflection method.

The temperature stability γf of the resonance frequency was determined by placing each sample in a temperature bath and measuring the change in trap frequency as the temperature changed from -3d'c to +700C. The results are shown in the table below. As is clear from the table, the dielectric ceramic of the present invention is
It can be seen that in the microwave region, the unloaded Q is large, the dielectric constant is relatively large, and the temperature stability of the resonance frequency is improved.

Samples 6, 7, and 8 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. Since the no-load Q is small and the resonant frequency changes greatly with temperature, it is excluded from the scope of the present invention. It was confirmed that the ceramic according to the present invention has a small dielectric loss even in the low frequency range and a small change in dielectric constant with temperature, so it is an excellent material for ceramic capacitors.

Claims (1)

[Claims] 1 General formula (1-w) (xBaO, yZnO・zTa_
In the composition represented by 2O_5)+wCaO・ZrO_2, 0.5≦X≦0.75, 0.1≦y≦0.3,
0.1≦z≦0.3, x+y+z=1,0<w≦0.9
A dielectric resonator material characterized by having a composition within the range of .