Na Shuai, Wong Lawrence L P, Chen Albert I H, Li Zhenhao, Macecek Mirek, Yeow John T W
Advanced Micro-/Nano-Devices Lab, Department of Systems Design Engineering, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada.
Techno Scientific Inc, 259 Edgeley Blvd, Concord, ON L4K 3Y5, Canada.
Ultrasonics. 2017 Apr;76:19-27. doi: 10.1016/j.ultras.2016.11.014. Epub 2016 Nov 23.
Air-coupled capacitive micromachined ultrasonic transducers (CMUTs) based on annular cell geometry have recently been reported. Finite element analysis and experimental studies have demonstrated their significant improvement in transmit efficiency compared with the conventional circular-cell CMUTs. Extending the previous work, this paper proposed a lumped element model of annular-cell CMUTs. Explicit expressions of the resonance frequency, modal vector, and static displacement of a clamped annular plate under uniform pressure were first derived based on the plate theory and curve fitting method. The lumped model of an annular CMUT cell was then developed by adopting the average displacement as the spatial variable. Using the proposed model, the ratio of average-to-maximum displacement was derived to be 8/15. Experimental and simulation studies on a fabricated annular CMUT cell verified the effectiveness of the lumped model. The proposed model provides an effective and efficient way to analyze and design air-coupled annular-cell CMUTs.
最近有报道称基于环形单元结构的空气耦合电容式微机电超声换能器（CMUT）。有限元分析和实验研究表明，与传统圆形单元CMUT相比，它们在发射效率上有显著提高。在先前工作的基础上，本文提出了环形单元CMUT的集总元件模型。首先基于板理论和曲线拟合方法，推导了均匀压力下夹紧环形板的共振频率、模态向量和静态位移的显式表达式。然后通过采用平均位移作为空间变量，建立了环形CMUT单元的集总模型。利用所提出的模型，得出平均位移与最大位移之比为8/15。对制作的环形CMUT单元进行的实验和模拟研究验证了集总模型的有效性。所提出的模型为分析和设计空气耦合环形单元CMUT提供了一种有效且高效的方法。
