Simulation model for CMUT with rapid structure fluid interaction in time domain

The dynamic deflection and acoustic radiation of thin plates or membranes greatly depends on the acoustic load on top of the vibrating structure. An electro-acousto-mechanical model has been built describing the solid-fluid interaction in time domain. The model is optimized for thin plates and membranes, and can be used for simulating CMUTs (Capacitive Micromachined Ultrasonic Transducers) in different fluids, but is also valid for any vibrating structure. The model provides accurate information about the sound pressure on the surface of the transducer, taking into account the dynamical force indicated to the vibrating structure by the fluid. All calculations are done in time domain keeping the nonlinear behavior of the transducer. Simulations results for CMUT designs with resonant frequencies between 5 an 40 MHz have been compared to measurements results on devices fabricated at Fraunhofer IPMS showing good agreement.