Design and characterization of capacitive micromachined ultrasonic transducers using finite element modeling

Capacitive Micromachined Ultrasonic Transducers (CMUTs) have been investigated using finite element models. A 2D axisymmetric model and a reduced order model illustrate the relationship between collapse voltage and electrode radius. A 3D solid model and a reduced order model calculate the resonant frequency of prestressed CMUT membranes.; The reduced order model is determined optimal due to its ability to calculate collapse voltage and resonant frequency with minimal computing time. A parametric study utilizing the optimum model illustrates that membrane radius and thickness are the most significant CMUT design parameters. Other significant parameters include the air permittivity, residual stress and membrane's modulus of elasticity, Poisson's ratio, and density.; The parameters are used to design CMUTs for a specific collapse voltage or resonant frequency. Using a design process, CMUTs can be designed within 10% of the specified values for resonant frequencies between 0.7--47.9 MHz and collapse voltages up to 3000V.