CaWO_4-Mg_2SiO_4陶瓷的微波介电性能与应用

为了使微波介电陶瓷在厘米波段获得应用,采用固相法制备了低εr、高Q·f值的(1–x)CaWO4-xMg2SiO4(x=0～1.0)介电陶瓷,并添加质量分数为5%的TiO2调节其τf。研究了其晶相结构和微波介电性能。结果表明,x≤0.2时,Mg2SiO4和CaWO4形成不完全固溶体;x=0.2时,在1300℃烧结2h所制得的陶瓷具有优良的微波介电性能:εr=9.58,Q·f=56400GHz,τf=–8.2×10–6/℃,并采用该材料制作了f0=5.4909GHz,插入损耗小于1.1dB,外形尺寸为5.0mm×2.5mm×4.0mm的两级片式介质带通滤波器。

Microwave dielectric properties and application of CaWO_4-Mg_2SiO_4 ceramics

In order to make microwave dielectric ceramics applicable in centimeter wave band,dielectric ceramics,(1–x)CaWO4-xMg2SiO4(x = 0～1.0),with low εr and high Q·f were prepared via traditional solid state reaction,and 5%(mass fraction) of TiO2 was also introduced to adjust the τf of ceramics.The crystal phase structure and the microwave dielectric properties of prepared ceramics were investigated.The results show that,when x≤0.2,incomplete solid solution is formed after sintering the mixture of Mg2SiO4,CaWO4 and TiO2.However,when x = 0.2,the ceramic sintered at 1 300 ℃ for 2 h exhibits excellent microwave dielectric properties,in which εr = 9.58,Q·f = 56 400 GHz and τf = –8.2×10–6 / ℃,and two-stage laminated dielectric band pass filter was fabricated using this ceramic.The center frequency,insertion loss and size of the fabricated filter is 5.490 9 GHz,below 1.1 dB and 5.0 mm×2.5 mm×4.0 mm respectively.