摘要
为确定体声波(BAW)梯形滤波器的阶数,使用仿真法研究了滤波器的带外抑制与并、串联薄膜体声波谐振器(FBAR)的电容比Cps和滤波器阶数N的关系。基于FBAR的Mason解析电路模型构建了1~6阶BAW梯形滤波器,Cps取值为1~6,对1~6阶BAW梯形滤波器进行仿真,取滤波器的左带外抑制进行统计并绘制曲线图。此外,BAW梯形滤波器的阶数可包括半阶数,用同样仿真法改变阶数(N=1.5,…,5.5)对滤波器进行仿真。仿真结果表明,当Cps一定时,带外抑制基本随滤波器的阶数等量增加。当滤波器的阶数一定时,带外抑制随Cps的增加而增加。在优化设计时,并、串联FBAR谐振器区面积比(即Cps)一般设置为1~4,在此范围内滤波器阶数每增加一阶,带外抑制平均增加约10dB;滤波器的阶数增加半阶时,带外抑制约增加整阶数的一半,即5dB,而此时通带内的插损基本保持不变。故设计滤波器时,根据设计指标中的带外抑制可初步确定滤波器的阶数。
In order to determine the order of the BAW ladder filter,the relationships among the out-of-band rejection of the filter and the capacitance ratio of the parallel/series FBAR as well as the order N of the filter are studied by using simulation method.The BAW ladder filters with one to six orders has been built based on the Mason model of FBAR.The value of capacitance ratio Cpsof parallel/series FBAR is from 1 to 6.The BAW ladder filters with 1-6 orders are simulated and the left out-of-band rejection of the filter is taken for statistics and drawing curves.In addition,we use the same simulation method to simulate the filter by changing the orders（N =1.5,...5.5）when the orders of the BAW ladder filter are including the half-order.The simulation results show that the out-of-band rejection the basically equal to the order of the filter when Cpsis constant,while the out-of-band rejection will increase with the increase of Cpswhen the orders of the filter are constant.When optimizing the design,the area ratio of the parallel/series FBAR（ie,Cps）is generally set at 1 to 4.In this range,the out-of-band rejection of will increase by about 10 dB when the order of the filter increases one.When the order of the filter is increased by half order,the out-of-band rejection is increased by about half of the whole order,that is 5 dB,while the insertion loss in the passband remains substantially unchanged.Therefore,when designing the filter,the order of the filter can be initially determined according to the out-of-band rejection in the design specifications.
作者
高杨
贾乐
韩超
GAO Yang;JIA Le;HAN Chao(Institute of Electronic Engineering,CAEP,Mianyang G21999,China;School of Information Engineering,Southwest University of Science and Technology,Mianyang G21010,Chinas;State Key Laboratory of Particle Detection and Electronics,Institute of IIigh Energy Physics,Chinese Academy of Sciences,Beijing 100049,China)
出处
《压电与声光》
CAS
CSCD
北大核心
2018年第5期641-645,共5页
Piezoelectrics & Acoustooptics
基金
国家自然科学基金资助项目(61574131)
中国工程物理研究院超精密加工技术重点实验室基金资助项目(2014ZA001)
核探测与核电子学国家重点实验室开放课题基金资助项目(2016KF-02)
关键词
滤波器
体声波
阶梯型
阶数
带外抑制
filter
bulk acoustic wave （BAW）
ladder
order
out-of-band rejection
