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3D-printing techniques are attracting a lot of interest in the sensors community as promising fabrication processes that guarantee customizability at low costs. In this work, the first uniaxial Ti6Al4V alloy accelerometer is designed, fabricated through the Laser Powder Bed Fusion (L-PBF) technique and tested. Experimental tests under accelerations show good agreement with theoretical predictions. With a differential sensitivity of 184fF/g and relative low dimensions (features as low as $500~\mu \text{m}$), the proposed accelerometer opens the path to a new class of 3D-printed metal sensors with high-performance, customizability and low-cost. [ABSTRACT FROM AUTHOR]

Numerical modelling of MicroElectroMechanical Systems (MEMS) resonators is still attracting increasing interest from the sensors community especially when the nonlinear regime is activated. Here, the dynamic response of two different types of double-ended tuning fork MEMS resonators is studied both in the linear and nonlinear regimes. A one Degree Of Freedom (1 dof) model able to predict the frequency response of the device is proposed. Geometric and electrostatic nonlinearities are simulated through Finite Elements and Integral Equations, respectively. The total dissipation of the resonator is computed by taking into account both the thermoelastic and the nonlinear fluid contributions. Experimental measurements performed on resonators fabricated in polysilicon and single crystal silicon validate the proposed model showing a very good agreement with theoretical predictions. [2020-0240] [ABSTRACT FROM AUTHOR]

Phononic crystals/metamaterials are attracting increasing interest because of their large variety of applications at both the macro and micro scales. In this work, a new metamaterial plate (metaplate) composed of innovative phononic crystal unit-cells is presented, numerically studied, fabricated at the microscale and experimentally tested. Numerical simulations and experimental tests demonstrate a complete 3D phononic bandgap that guarantees a complete vibration isolation in a certain range of frequency. Moreover, its compatibility with Micro Electro Mechanical Systems (MEMS) fabrication processes suggests applications for vibration isolation of MEMS resonant devices. The measured transmission diagram shows a -30 dB attenuation level, which is in good agreement with numerical predictions. The proposed design opens up new perspectives for the development of vibration isolation applications for MEMS resonators. [2020-0069] [ABSTRACT FROM AUTHOR]

Epitaxial polysilicon is a cheap material that has been used in the microelectromechanical system (MEMS) industry for a long time. Its relatively large $-$ 30  ppm/K temperature coefficient of frequency (TCf) has prevented its widespread use in real-time clock (RTC) applications. This article investigates the possibility to use this material to build resonators to be used in RTC applications, starting from the assumptions that the TCf of polysilicon is large but very repeatable. This would allow a large manufacturer to use a time-saving, thus inexpensive, family compensation, where the calibration procedure is computed for a very small fraction of the population of produced RTCs and then applied to the entire production output. This article presents a novel design of capacitive resonators for RTCs and demonstrates that the spread of the part-to-part temperature dependence is low enough to allow an electronic family compensation to within  $ \pm$ 20 ppm of the output frequency. [ABSTRACT FROM AUTHOR]

In this paper, the innovative fabrication process for electro-mechanical sensors, born from the smart combination of 3D-printing and wet-metallization and previously demonstrated in a $z$ -axis accelerometer, is employed to fabricate a fully 3D three-axis accelerometer. Thanks to the three-dimensionality of the printing process, a central symmetry along the three axes can be obtained by design, unlike in common 2D-like microfabrication processes. Electrostatic differential sensing is obtained through the metallization procedure and the subsequent mounting of fixed electrodes on an external frame of the mechanical structure. Experimental tests under accelerations show good agreement with theoretical predictions. With relatively small dimensions (features as low as $450~\mu \text{m}$), very high capacitive sensitivity (> 200 fF/g) and low theoretical thermo-mechanical noise, the proposed three-axis accelerometer represents a further step towards the development of an innovative fabrication process for high-performance, customizable, and low-cost electro-mechanical devices. [ABSTRACT FROM AUTHOR]

This paper investigates different topologies of springs used to couple the orthogonal translational motion of proof masses in Micro-Electro-Mechanical Systems (MEMS). This type of coupling is a key issue, since the dynamic response, and hence, the performance of various devices (e.g., MEMS gyroscopes) critically depends on the mechanical behavior of such deformable components. We first analytically investigate the problem through a model based on a modified second-order Timoshenko beam theory developed for both compact and built-up section beams. Its predictions inspire the design of three test structures, whose purpose is to highlight, through different spring topologies, the transition from a hardening behavior to a softening behavior, with possible intermediate optimum conditions for linear response at large displacements. The structures are characterized in detail, with variable forced displacements at resonance (25 kHz) up to about $10~\mu \text{m}$. Experiments validate the model predictions in all the considered situations. [2018-0181] [ABSTRACT FROM AUTHOR]

This paper reports the developments toward an integrated, tri-axial, frequency-modulated, consumer-grade, and microelectromechanical system (MEMS) gyroscope. A custom low-power (160 μA), low-phase-noise integrated circuit is designed specifically for frequency-modulated operation. Both yaw- and pitch-rate sensing systems are demonstrated by coupling the circuit with two novel micromachined structures fabricated with a 24- μm-thick industrial process. In operation, both gyroscopes show a repeatable and stable scale factor, with less than 0.55% of part-to-part variability, obtained with no any calibration, and 35 ppm/ ^\circ C of variability over a 25–70  ^\circ C temperature range. [ABSTRACT FROM PUBLISHER]

In this paper, additive manufacturing and wet metallization process are combined to fabricate three prototypes of differential electro-mechanical z -axis accelerometers. The smart combination of existing fabrication processes makes the proposed fabrication flow unique in the sensors field. The mechanical design of the three proposed devices exploits the three-dimensionality of the 3-D-printing technique and the electrostatic differential readout is allowed thanks to the wet-metallization process of the printed structure. Experimental measurements show a very good agreement with theoretical predictions thus proving a good reliability of the proposed design flow and fabrication process. With their relative small footprints (minimum dimension in the order of hundreds of \mu \textm ), good performances (sensitivity >12 fF/g, sub % linearity error up to 11 g of full scale and theoretical noise estimation of few tens of ng/ $\surd $ Hz) and high customizability, they represent an important step toward novel application fields of inertial sensors. [ABSTRACT FROM PUBLISHER]