无铅压电陶瓷中频滤波器的研制

Manufacturing of Middle Frequency Filters Using Lead-free Piezoelectric Ceramics

采用本组发明的BNKLT系无铅压电陶瓷,研制了中频陶瓷滤波器.该体系陶瓷具有较高的使用温度,在160℃以上仍然具有较强压电性.利用此体系材料,采用轮廓振动模式,制作了插损约为3dB,中心频率约为530kHz,带宽约为8.8kHz,左、右选择性均良好的无铅压电陶瓷单片式中频滤波器;采用全电极径向振动模式,制作了插入损耗小于6dB、阻带损耗大于30dB、频率特性曲线平滑、具有良好选择性的中频(IF=460kHz)多节带通滤波器.与含铅压电陶瓷多节滤波器相比,BNKLT无铅压电陶瓷滤波器的特性还有差距,有待改进;而对单片式滤波器来说,除中心频率以外,大部分指标可满足村田公司同类含铅陶瓷中频滤波器(SFU系列)产品标准,具有良好的应用前景.

BNKLT lead-free piezoelectric ceramics invented in authors group were used for making middle frequency ceramic filters. The BNKLT system ceramics have higher working temperature, which still appear a strong piezoelectric properties above 160℃. Using the skeletal vibration mode, the BNKLT system is fabricated into the single chip middle frequency filter with the center frequency about 530kHz. The insertion loss is about 3dB, and the bandwidth is about 8.8 kHz. The left and right choose character is very goo...