The past few decades have witnessed the ultra-fast development of wireless telecommunication systems, such as mobile communication, global positioning, and data transmission systems. In these applications, radio frequency (RF) acoustic devices, such as bulk acoustic waves (BAW) and surface acoustic waves (SAW) devices, play an important role. As the integration technology of BAW and SAW devices is becoming more mature day by day, their application in the physical and biochemical sensing and actuating fields has also gradually expanded. This has led to a profusion of associated literature, and this article particularly aims to help young professionals and students obtain a comprehensive overview of such acoustic technologies. In this perspective, we report and discuss the key basic principles of SAW and BAW devices and their typical geometries and electrical characterization methodology. Regarding BAW devices, we give particular attention to film bulk acoustic resonators (FBARs), due to their advantages in terms of high frequency operation and integrability. Examples illustrating their application as RF filters, physical sensors and actuators, and biochemical sensors are presented. We then discuss recent promising studies that pave the way for the exploitation of these elastic wave devices for new applications that fit into current challenges, especially in quantum acoustics (single-electron probe/control and coherent coupling between magnons and phonons) or in other fields.

Sensors based on "resonance phenomenon" span a broad spectrum of important current applications including detection of biological and chemical agents, and measurements of physical quantities. Resonance phenomena occur with all types of waves: electromagnetic, optic, and acoustic. This review reports about the most recent advances in the design and applications of resonant "passive" sensors, i.e. resonant sensors able to operate with a distant power source and/or able to communicate with a distant transceiver. The sensors considered in this review include acoustic, magnetoelastic, and electromagnetic transducers. They are presented through their relevant technological aspects and through they major advantages which include their integrability within embedded systems and/or systems requiring energy autonomy. Furthermore, the use of these resonant sensors is illustrated in a large variety of applications, ranging from environmental monitoring, structural health monitoring, food packaging monitoring, wearable or implanted sensors for the monitoring of physiological parameters in healthcare related applications, to IoT and future industry monitoring applications.

We report inkjet printing as an alternative deposition method for low-cost gas or humidity sensors based on graphene oxide (GO)-coated Love wave devices. Our inkjet printing method paves the way toward massive, large-area industrial production of multi-layered GO chemical sensing films for volatile organic compounds and relative humidity (RH) detection applications. The adsorption of vapor compounds on GO led to the sensitivities of 30 Hz/ppm, 24 Hz/ppm, and 2.4 kHz/1% of ethanol (C ₂ H ₆ O), toluene (C ₇ H ₈ ), and RH, respectively. Electrical, gaseous, and RH characterization analyses showed that this GO-based inkjet printing method is one of the most promising features for inexpensive and high-speed patterning devices for high demanding gas trace or RH sensing applications.

International audienceA new generation of passive gas sensors that works at millimeter-wave frequency (50 to 70 GHz) incorporating sensitive material is presented. The sensor uses a microwave planar dielectric resonator operating with whispering gallery-modes. The dielectric resonator (DR) is covered by SnO2 thin film as sensitive layer. A gas adsorption makes the SnO2 effective dielectric parameters changing namely its permittivity. Such changing modifies the resonance frequency of the resonator. Here, the proof of concept is demonstrated thorough full wave simulations. This sensor is a passive circuit and has great potential for wireless sensing network applications