水下偵測用電容式超音波換能器的分析與輻射聲場之模擬

The Design and Radiation Pattern Simulation of Capacitive Micromachined Ultrasonic Transducers for Underwater Detecting

本文應用修正之薄膜振動模型、聲音輻射阻抗及機電二埠小信號轉換電路，同時考慮直流偏壓及上電極尺寸的薄膜振動行為，發展更精確的電容式超音波換能器等效電路，討論水下偵測用超音波換能器之頻寬特性的影響參數，並模擬二維陣列超音波換能器輻射聲場圖形及換能器聲波柱的聚焦與轉向，最後提出一套二維陣列超音波傳輸器的設計準則。 This paper presents a more accurate equivalent circuit model of capacitive micromachined ultrasonic transducer, (cMUT) by combining bias and top electrode mass effects, and using the modified model of vibration membrane, acoustical radiation impedance, and small signal electromechanical two ports network analysis. Then, we discuss the parameters to operate in wide band, (low Q factor) for underwater detecting cMUTs. The simulation of sound pressure radiation pattern, acoustic beam forming and steering of two dimension transmitter arrays are completed finally and presents a designed criterion for designing two dimension transmitter arrays.