Dario Paci

Optimization of a piezoelectric energy harvester for environmental broadband vibrations

Energy scavenging systems (ESS) can be important, theoretically endless, sources of energy. In the future, they could recharge or even replace batteries. In this paper a design methodology is presented in order to maximize the harvested energy and the transduction efficiency of a cantilever-like piezoelectric scavenger. The role of geometrical parameters is investigated through a theoretical analysis based on an equivalent lumped-parameter circuit, while their optimum value is chosen by means of FEM simulations.

Simple model for the performance of realistic AMR magnetic field sensors

We report on a numerical model for assessing the performance of realistic multi-strip AMR sensors. The model is extensively validated against experimental data and accurately predicts the output characteristics of different devices without any fitting parameters. Moreover, a simpler and computationally faster model employing constant effective demagnetization coefficients is presented, which is able to reproduce the correct device behavior and can be used as a fast device optimization tool.

Optimization of Lorentz-force MEMS magnetometers using rarefied-gas-theory

We review the design of Lorentz force-based magnetometers to be employed in MEMS inertial measurement units. Taking into account the constraints of an industrial MEMS technology already used for accelerometers and gyroscopes, it has been recently shown that standard designs have intrinsic limitations. E.g. in the classical magnetometer operated at resonance where two parallel current carrying springs are connected by a central shuttle on which sensing parallel plates are mounted, the sensitivity does not depend on the number of plates and is limited to typical values around 1aF/(μT mA) at 1mbar. In this paper two solutions have been investigated: springs have been used for both actuation and sensing, with no sensing plates; exploiting better knowledge of rarefied gas dynamics, new stators have been designed. The combination of these factors has increased the sensitivity to 4.5aF/(μT mA) at 1mbar as predicted by numerical models and verified in experiments.