【摘要】：近年來,隨著無線通訊技術(shù)的快速發(fā)展,對以微波介質(zhì)陶瓷為基礎(chǔ)的微波器件提出了小型化、高品質(zhì)化、低成本化的新要求。低溫共燒技術(shù)和高介電常數(shù)(εr)微波介質(zhì)陶瓷是實現(xiàn)通訊設(shè)備片式化和微型化的有效方法。目前,低燒和低溫共燒(LTCC)介質(zhì)材料多集中于低介微波陶瓷體系,而高介微波陶瓷體系常常存在燒結(jié)溫度高,諧振頻率溫度系數(shù)(ηf)大,品質(zhì)因數(shù)(Q)較低的缺點。因此,尋找具有低燒結(jié)溫度(≤1100℃)和綜合性能優(yōu)異(εr≥20,Q×f≥5000GHz,ηf≈±10 ppm/℃)的新型微波介質(zhì)材料成為當務(wù)之急。本文采用復(fù)合材料的工藝原理制備新型中、高介電常數(shù)微波介質(zhì)陶瓷,采用XRD、SEM、EDS和網(wǎng)絡(luò)分析儀,系統(tǒng)研究了幾種微波介質(zhì)陶瓷的燒結(jié)特性、晶體結(jié)構(gòu)、顯微組織和介電性能,得到如下結(jié)果:1.(1-x)Li3Nb O4-x Ca0.8Sr0.2Ti O3(x=0.1-0.4)體系:XRD和EDS結(jié)果表明,在0.1≤x≤0.4成分范圍內(nèi),所有樣品均由鈣鈦礦結(jié)構(gòu)的鈦酸鍶和Li3Nb O4兩相共存構(gòu)成。隨著x值增大,εr從18.6增到31.2;Q×f值從86962GHz降至9472GHz;ηf從-30 ppm/?C增加到+119ppm/?C。實測結(jié)果與理論計算值及變化規(guī)律相一致。當x=0.2時,在1075℃下燒結(jié)的陶瓷的介電性能最優(yōu):εr=21.4,Q×f=49,276GHz,ηf=+5.15 ppm/℃。2.(1-x)Bi VO4-x Li0.5Re0.5WO4(Re=La,Nd,Sm)(x=0.05-0.11)體系:XRD結(jié)果表明,該體系在替代范圍內(nèi)均形成了單斜晶系Bi VO4結(jié)構(gòu)固溶體,且晶胞體積隨著x的增加呈近似線性增加。SEM結(jié)果表明,該體系的最佳燒結(jié)溫度均為750℃。(1-x)Bi VO4-x Li0.5La0.5WO4在x=0.09時,介電性能最理想:εr=76.65,Q×f=6789.4GHz,ηf=+7.3ppm/℃;(1-x)Bi VO4-x Li0.5Nd0.5WO4在x=0.08時,介電性能最優(yōu):εr=71.8,Q×f=7481.7GHz,ηf=0.8ppm/℃;(1-x)Bi VO4-x Li0.5Sm0.5WO4在x=0.07時,介電性能最好:εr=74.7,Q×f=9054GHz和ηf=-1.6ppm/℃。該系陶瓷材料有望用于微波天線和LTCC領(lǐng)域。3.(1-x)Ca0.8Sr0.2Ti O3-x Li0.5Sm0.5Ti O3(CST-LST)體系:XRD結(jié)果表明,所有樣品均為正交晶系鈣鈦礦結(jié)構(gòu)。當x=0.8,1250℃燒結(jié)的陶瓷介電性能最好。添加5wt%BCB可使CST-LST陶瓷的燒結(jié)溫度從1250℃降至950℃,微波介電性能優(yōu)異:εr=66.7,Q×f=3222 GHz,ηf=-21.3ppm/℃。添加適量的Ti O2能有效地調(diào)節(jié)ηf和提高εr。950℃/4h時CST-LST+5wt%BCB+1.5wt%Ti O2樣品的微波介電性能為:εr=71.6,Q×f=3441GHz,ηf=-10.8ppm/℃。該陶瓷與Ag電極共燒相容性好,有望應(yīng)用于LTCC領(lǐng)域。
[Abstract]:In recent years, with the rapid development of wireless communication technology, microwave devices based on microwave dielectric ceramics have put forward the new requirements of miniaturization, high quality and low cost. Low temperature co-firing and high dielectric constant (蔚 r) microwave dielectric ceramics are effective methods to realize chip and miniaturization of communication equipment. At present, low and low temperature co-fired (LTCC) dielectric materials are mostly concentrated in low dielectric microwave ceramic systems. However, high dielectric microwave ceramic systems often have the disadvantages of high sintering temperature, large temperature coefficient of resonance frequency (畏 f) and low quality factor (Q). Therefore, it is urgent to find new microwave dielectric materials with low sintering temperature (鈮，

本文編號：2214988