This paper covers the study of high-frequency (~ 1 GHz) ZnO piezoelectric transducer integrated on a silicon substrate able to generate both compressional and shear acoustic waves. First, to promote the longitudinal mode, an electrical matching of the transducer in this high-frequency range is effectuated. Second, to promote shear waves, new deposition conditions were applied, giving thin zinc oxide films of inclined c-axis. The RF microprobe was used to validate the transducer design and to conduct the viscosity measurements. Thus, the shear and the volume viscosity of a water droplet were measured.

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This Letter reports on a work performed to fabricate and characterize a silicon micro-machined cavity dedicated to micro-resolution Ultra-High Frequency imaging in microfluidics and microbiological applications using one-channel time reversal. Time reversal provides the means to spatially and temporally localize elastic energy on a receiver. Here, the arrays of zinc oxide micro transducers are coupled with a 400  μm thick silicon wafer containing micromachined structures for acoustical field confinement. Characterization of the diffused acoustic field and time-reversal retro-focusing are reported. The transducers are wideband in the 0.2–2 GHz range with a central frequency of 0.9 GHz.

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Cette étude propose la conception complète d’un système de suivi à distance des sollicitations mécaniques dans les machines électriques afin de répondre aux problématiques de l’industrie 4.0 et de la maintenance prédictive. Elle s’appuie sur la conception, la fabrication et la caractérisation de MEMS acoustiques hautes fréquences (bande ISM à 433MHz) intégrés à un banc de test et comparés aux performances de jauges de déformation commerciales.