Equivalent circuit-based analysis of CMUT cell dynamics in arrays

Area of Science:

• Acoustics
• Microelectromechanical Systems (MEMS)
• Electrical Engineering

Background:

• Capacitive micromachined ultrasonic transducers (CMUTs) are typically built as large, densely packed cell arrays.
• Analyzing the acoustic interactions between closely packed CMUT cells is crucial for understanding array performance.

Purpose of the Study:

• To develop and validate an equivalent circuit model for analyzing CMUT arrays with multiple cells.
• To investigate the impact of mutual acoustic interactions on CMUT array performance.

Main Methods:

• An equivalent circuit model was developed to analyze CMUT arrays.
• Cells were coupled using a radiation impedance matrix to account for acoustic interactions.
• An approximation for mutual radiation impedance between circular cells was derived.
• Finite Element Method (FEM) simulations were used for validation.

Main Results:

• The equivalent circuit model accurately predicts the performance of CMUT arrays.
• The model accounts for mutual acoustic interactions through the immersion medium.
• Computational complexity is reduced for large arrays using the proposed approximation.
• Model results closely matched FEM simulations for small cell arrays.

Conclusions:

• The proposed equivalent circuit model provides an efficient and accurate method for analyzing CMUT arrays.
• This model enables rapid prediction of both linear and nonlinear responses for CMUT arrays of any size.