MULTIOBJECTIVE PARETO-BASED OPTIMIZATION OF pMUT HYDROPHONE WITH PIEZOELECTRIC ACTIVE DIAPHRAGM

The design of high-sensitive hydrophones is one of the research interests in underwater acoustics. Due to progress of micro- and nanotechnology the most attention of researchers is attracted by the transducers that use the micro-electromechanical system (MEMS) concept. Piezoelectric micro-machined ultrasonic transducers (pMUTs) present a new approach to sound detection and generation that can overcome the shortcomings of conventional transducers. For accurate ultrasound field measurement, small size hydrophones which are smaller than the acoustic wavelength are required for providing an omnidirectional response and avoid spatial averaging. This paper presents some results of multiobjective optimization for membrane-type piezoceramic MEMS based transducers. We investigate the miniaturized membrane-type sensor with perforated holes in the active PZT and intermediate membranes, with the protective plates and a vacuum chamber. An influence of the protective plate elastic and viscous properties, the dimensions and the relative area of the perforated holes on the sensitivity's frequency response of the hydrophone was studied for the broadening and equalizes the operating frequency band. We optimize these key parameters using the Pareto approach with the finite element (FE) model of coupled piezoelectric-acoustic problem. Finally, the set of optimized hydrophone structures and some examples of obtained sensitivity frequency response are demonstrated.