This paper deals with the design, simulation and characterization of polymer-based piezoelectric micromachined ultrasound transducers (PMUT) (arrays) intended for short-range gesture recognition applications. The presented process flow is fully compatible with existing flat-panel display fabrication. Finite element models were developed for the evaluation of the frequency response, deflection and acoustic pressure output of single PMUT as a function of the membrane diameter. A laser Doppler vibrometer was used to measure the frequency response, membrane velocity and displacement, as well as mode shapes of the microfabricated PMUT in air. An optical microphone was used to measure the pressure emitted by a single PMUT at various distances along the normal axis of the oscillating membrane. A strong correlation between simulations and measurement results is shown. The device geometries most suitable for shortrange gesture recognition purposes are selected and the radiation pattern of square arrays is analyzed using simulations. The resonance properties of single PMUT in an array are determined using measurements. An optimized array is used to demonstrate pulse-echo measurements, and the requirements for a simple gesture recognition platform are elucidated.

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This paper describes a robust and efficient method to obtain the steady-state, nonlinear behaviour of large arrays of electrically actuated micromembranes vibrating in a fluid. The nonlinear electromechanical behavior and the multiple vibration harmonics it creates are fully taken into account thanks to a multiharmonic finite element formulation, generated automatically using symbolic calculation. A domain decomposition method allows to consider large arrays of micromembranes by efficiently distributing the computational cost on parallel computers. Two-and three-dimensional examples highlight the main properties of the proposed method.

The aim of this paper is to compare several domain decomposition schemes for nonlinear, coupled electromechanical problems. Both staggered and monolithic electrostatic/elastic formulations are combined with an overlapping domain decomposition method applied either to the uncoupled, linear staggered resolutions or to the monolithic nonlinear system. The influence of the elastic waves frequency, of the electrostatic potential and of the mesh on the convergence rate is investigated on a simple 2D model of a vibrating micromembrane array.

This paper describes a method to automatically derive multiharmonic finite element formulations for coupled, nonlinear electromechanical problems. It focuses on models of electrically actuated micromembranes using both a staggered and a monolithic Newton iteration scheme. Two-and three-dimensional examples highlight the main properties of the proposed method.