An accurate model for capacitive micromachined ultrasonic transducers
An accurate model for capacitive micromachined ultrasonic transducers
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DOI：
10.1109/58.985700
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发表时间：
2002-02-01
影响因子：
3.6
通讯作者：
Pappalardo, M
中科院分区：
文献类型：
--
作者：
Caronti, A;Caliano, G;Pappalardo, M
电容式微机械超声换能器（cMUTs）的建模是基于一个具有电气和机械侧的双端口网络。为了得到分布模型，必须求出换能器各元件的膜片运动微分方程的解。以前的工作忽略了膜片后面空腔的机械负荷，即内部气体的影响。在本文中，我们提出了一个考虑这种影响的cmut分布式模型。得到了膜的机械阻抗的封闭解，包括由于膜的刚度和腔内空气的压缩而产生的恢复力的影响。基于该模型的仿真结果与最近文献报道的两种cmut的实验数据进行了比较。结果表明，空气的压缩对空气换能器的基频有显著影响，与不考虑振动隔膜和气垫之间相互作用的模型的预测偏差约为22%。
Modeling of capacitive micromachined ultrasonic transducers (cMUTs) is based on a two-port network with an electrical and a mechanical side. To obtain a distributed model, a solution of the differential equation of motion of the diaphragm for each element of the transducer has to be found. Previous works omit the mechanical load of the cavity behind the diaphragm, i.e., the effect of the gas inside. In this paper, we propose a distributed model for cMUTs that takes this effect into account. A closed-form solution of the mechanical impedance of the membranes has been obtained, including the effect of the restoring forces because of the stiffness of the membrane and because of the compression of the air in the cavity. Simulation results based on the presented model are compared with the experimental data for two types of cMUTs reported in the recent literature. It is demonstrated that the compression of the air has a significant effect on the fundamental frequency of the air transducer, with a deviation of about 22% from the prediction of a model that does not consider the interaction between the vibrating diaphragm and the air cushion.