| With the development of modern communication technologies,the demand for related components is increasing.In recent years,microwave dielectric ceramics developed rapidly,because the microwave components made by them have many advantages,such as small,cheap,light weight,stable performance and so on.Therefore,they can meet the miniaturization and integration requirements of modern communication tools.LTCC(Low Temperature Co-fired Ceramic)is a multi-layer circuit made by laminating unsintered ceramic material together with printed interconnected conductors,circuits and components.The structure is fired into an integrated ceramic multi-layer material.LTCC technology is a remarkable integrated component technology developed in recent years.Li2Mg3SnO6 ceramics are microwave components suitable for LTCC applications because of their lower dielectric constants and higher quality factor.However,they have the disadvantages of higher sintering temperatures and poor temperature stability.Moreover,they are difficulty to compact and easy to generate the second phases,which hinder their applications in LTCC.In view of the shortcomings of Li2Mg3SnO6 ceramics,Bi2O3-LiF-CaF2-TiO2,LiF,and(La0.5Na0.5)TiO3 were respectively added to improve sintering properties,adjust temperature stability of Li2Mg3SnO6 ceramics,and the following results were obtained:1.Choose Bi2O3-LiF-CaF2-TiO2(BLCT)powers as the sintering aid,Li2Mg3SnO6-x wt%BLCT(x=4、8、12、16)ceramics were prepared.The sintering properties and microwave dielectric properties of Li2Mg3SnO6 ceramics were studied when x increased from 4 to 16.The results showed that the densities increased continuously with the increase of x.Moreover,the densification sintering temperature of the ceramics decreased due to the addition of Bi2O3-LiF-CaF2-TiO2.Eventually,at x=4,Li2Mg3SnO6 ceramics sintered at 1070℃ have the best microwave dielectric properties:εr=11.6,Qxf=24000 GHz.2.Li2Mg3SnO6-x wt%LiF(x=1、2、4、6)ceramics were prepared.The effects of x increased from 1 to 6 on the properties of Li2Mg3SnO6 ceramics were studied.The results showed that the sintering temperatures of Li2Mg3SnO6 ceramics were reduced to 900℃ when LiF content x≥4.At x=4,Li2Mg3SnO6 ceramics sintered at 900 0C,having the microwave dielectric properties:εr=12.3,Qxf=96280 GHz,τf=-40.7 ppm/℃.The samples were compatible with Ag electrode and were suitable for microwave dielectric substrates and millimeter wave communication applications.3.Choose(La0.5Na0.5)TiO3 as temperature compensator,and(1-x)Li2Mg3SnO6-x(La0.5Na0.5)TiO3-4 wt%LiF ceramics were prepared.All samples realized densification at 900℃.With the addition of LiF,the densification sintering temperatures of ceramics were reduced,The dielectric constants of(1-x)LMS-xLNT-4 wt%LiF ceramics were between 11.4 to 12.0.0.8LMS-0.2LNT-4 wt%LiF ceramics sintered at 935℃ have the maximum Q×f value of 13100 GHz.The τf values of ceramics were from negative to positive with the increase of x,indicating that(La0.5Na0.5)TiO3 can effectively control the temperature stability of Li2Mg3SnO6 ceramics.Figure 29;table 5;reference 100... |
