单片硅酸镓镧晶体滤波器的研制

Development of Monolithic LGS Crystal Filter

比较了几种压电晶体的物理性质,采用硅酸镓镧（La3Ga5SiO14,LGS）晶体材料设计了一种6极点单片晶体滤波器。该滤波器中心频率为4.8 MHz,3 dB带宽20 kHz,工作温度范围为-55~125℃,体积仅32.2 mm×12.6 mm×8.5 mm。实验证明,LGS晶体温度性能好,机电耦合系数高,适合制作中等带宽的晶体滤波器,该研究填补了国内该领域的空白。

The physic characteristics of some piezoelectric crystals have been compared in this paper.A 6-pole monolithic crystal filter（MCF） has been designed by using LGS crystal.The fabricated filter has the center frequecncy of 4.8 MHz,3 dB band width of 20 kHz,operating temperature range of-55 ℃ to ＋125 ℃ and the totalvolume of 32.2 mm×12.6 mm×8.5 mm.The experimental results showed that LGS crystal had good thermal stabilities and higher electromachanical coupling coefficient greater than quartz,and thus was suitable for realizing middle bandwidth crystal filter.The development of the filter has filled the gap in the LGS crystal filter study in domestic.