Articles techniques et présentations

The shear mode of film bulk acoustic resonators (FBARs) is preferred to the longitudinal mode owing to its lower acoustic losses in a liquid. However in addition to mass loading, the resonance is also affected by temperature and liquid viscosity. These two parameters can either be sensed ... En savoir plus

This study is focused on using a thermoelectric device (TED) as an alternative to the cryogenic liquid for cooling cryosurgical probe used for cancerous tissue ablation. Thermoelectric device, namely Peltier, is a solid state device which converts electric current to thermal gradient. In ... En savoir plus

A COMSOL Multiphysics® simulation was used to simulate the behavior of a micro-membrane (Acoustic Pixel) to be used as a potential acoustic transducer. The MEMS and Piezoelectric devices interfaces were used to simulate such transducer. A four-cantilever spring configuration is initially ... En savoir plus

Self-heating is a problem to consider for Ultrasound Imaging probes. Since the probe is in contact with the skin, it’s necessary to find a solution to lower the front face temperature in order to avoid patient discomfort, even at the most demanding operating condition. One solution ... En savoir plus

Finite element (FE) modelling of ultrasonic propagation using COMSOL Multiphysics® simulations can be used to create images of waves. Unfortunately, in time-stepping solutions, it is possible for numerical instabilities to grow large and dominate the solution adversely. Any design of ... En savoir plus

Ultrasound Imaging probes are specific devices that require a very detailed design of acoustic impedance match for the stack of layers that form the probe head (1,3). These are typically made of silicone rubber, special epoxy resins, polyurethanes and, of course, piezoelectric ... En savoir plus

Energy harvesting from environmental vibration nowadays is feasible because of natural oscillations like that caused by air or liquid flow and by exhalation or the heartbeat of a human body. This vibration frequency is typically low (in order of less than 1 kHz). Accordingly, low ... En savoir plus

Sensors have diverse applications ranging from the medical field to space exploration. They convert physical parameters such as temperature, pressure, humidity etc. into an electrical output. The discovery of piezoresistivity property of silicon and germanium led to miniaturization of ... En savoir plus

The use of piezoelectric materials in hearing aid loudspeakers, also called receivers, presents technical and economic advantages such as reducing the number of parts of the system and its manufacturing cost. However, the performance of such systems is still not competitive when compared ... En savoir plus

Logging-while-drilling (LWD) acoustic transducers provide real-time data about the geologic and geophysical properties of the borehole that ensure safety margins and optimize completion. It is important to understand what causes the different resonance modes in the transmitter and obtain ... En savoir plus