Finite-Element Analysis of Microelectromechanical Membranes Vibration

The influence of the capacitive micromachined ultrasound transducers (cMUT) design and operation regimes on the parameters of received signal during the pulse-echo operation was investigated with finite element analysis (FEA). FEA representation of pulse-echo response with electrical signals simulated at the input and output of a model with exploring of conditions of the single cMUT cell operation in immersion was created and experimentally verified. It was found the correlation between the simulated and measured data to be not worse than 0.92. Most of the difference between the data we attribute to post-receive oscillations present in measured signal. Then the influence of the cell design (diameter, vacuum gap size) and operating conditions (excitation pulse amplitude, duration and bias voltage) was explored by simulation. The increase of the pulse/echo effectiveness by increasing of the cell diameter was found. It was further found the negative relationship between the vacuum gap size and the amplitude of the received signal. We also confirm that bias voltage and excitation pulse duration need to be optimized, because the optimization allows creating certain peak performance conditions.