JPS5935485B2 - Porcelain materials for dielectric resonators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ceramic materials for dielectric resonators, particularly pr6o1,
This article concerns a ceramic material for dielectric resonators composed of the following components: dielectric constant (
ε) is large, the dielectric loss (D=1/Q) in the microwave frequency band is small, and the temperature dependence of the resonant frequency when a dielectric resonator is used is linear, and its temperature coefficient (τf ) is intended to provide an excellent ceramic material for dielectric resonators, which can be varied over a wide range by changing the composition.

Conventionally, dielectric materials have been applied to impedance matching of microwave circuits, dielectric resonators, etc. in the microwave frequency region.

In recent years, especially as the integration technology of microwave circuits has progressed, dielectric resonators using dielectric ceramics with high permittivity and low loss have been used to stabilize the frequency of oscillators and miniaturize them. This is being actively pursued. Conventionally, these dielectric materials have been used in combination with BaO-TiO2-based porcelain, porcelain in which a portion of BaO-TiO2 is replaced with other elements, and dielectric porcelain whose permittivity has a negative temperature coefficient. There are many cases. However, these have many problems in practical use, such as a small dielectric constant, a large dielectric loss, or an inability to obtain a desired temperature coefficient when used as a dielectric resonator. As a result of examining various materials that do not have these drawbacks, the inventors determined the general formula to be XP.
In the composition represented by r01l-yTi02, 15
It has been found that a ceramic having a composition within the ranges of ≦X≦65 (mol%), 35≦y≦85 (mol%), and x+y=100 (mol cf6) is an excellent ceramic for dielectric resonators.

The present invention will be explained below based on Examples. As starting materials, chemically high-purity TiO2 and pr6O,1 were weighed to give a predetermined composition, and wet-mixed with pure water in a rubber-lined ball mill equipped with an agate ball. This mixture was taken out from the ball mill, dried, and then calcined in air at a temperature of 900° C. for 2 hours. The calcined product was wet-milled together with pure water in the ball mill described above. After dehydrating and drying the crushed slurry, 8% by weight of a 3% polyvinyl alcohol solution was added to the powder as a binder to make it homogeneous, and the mixture was sized through a 32 mesh sieve. The sized powder is molded at a pressure of 8 using a mold and hydraulic press.
It was molded into a disc made by 0000 Co., Ltd., with a diameter of 2 Own and a thickness of about 10 m. The molded body was placed in a high-purity alumina sagger and fired by holding it in the air at a temperature within the range of 1250 to 1450°C for 1 hour depending on the composition to obtain porcelain having the composition shown in the table. The obtained ceramic was used in a microwave dielectric resonator, and the resonant frequency and no-load Q were measured. Further, the dielectric constant (εr) was calculated from the resonance frequency. The temperature coefficient (τf) of the resonance frequency was determined in the range of -40°C to 80°C. The resonant frequency is 2-4GH2. The experimental results are shown in the table. Sample number 1 marked with * in the table
and 7 are comparative examples outside the scope of the present invention, and sample numbers 2 to 6
This is an example within the scope of the present invention. That is, when the amount of PrOu (a) is less than 15 mol% and the amount of TiO3 (y) is 8
If it exceeds the milk mol%, the unloaded Q will drop significantly, and if x is more than 65 mol% and y is less than 35 mol%, the dielectric constant and the unloaded Q will drop significantly, which is undesirable. excluded from the scope of the invention. As is clear from the table, the dielectric ceramics within the scope of the present invention have a large no-load Q and a large dielectric constant in the microwave region.

Claims (1)

[Claims] 1 A porcelain composition consisting of praseodymium oxide and titanium oxide, whose composition formula is xPrO_1_1_/_6-yTi
When expressed as O_2, its component composition is 15≦x≦65
(mol%), 35≦y≦85 (mol%), x+y=10
A ceramic material for a dielectric resonator, characterized in that the content is in the range of 0 (mol%).