Characterizing ultrasonic transducers in real time
Ultrasonic transducers produced using microsystems technology are promising for medical ultrasonic applications. Here, you essentially make a distinction between so-called pMUTs and cMUTs (piezoelectric Micromachined Ultrasonic Transducers and capacitive Micromachined Ultrasonic Transducers respectively).
cMUTs have unique properties compared with conventional elements. Thanks to the membrane’s bending mode deflection shape, the transducer’s mechanical impedance reduces, while energy transfer to the ambient medium improves at the same time. Microfabrication also enables affordable series production of cMUTs using semiconductor technology. The semiconductor switching circuit can be directly integrated on the same chip, so as to simply create even large-sized 1D or more complicated 2D array configurations.
Polytec Magazine
Simulation vs. measurement
FEM simulation and measurement validation of an ultrasound transducer
Diagnosis in a breath
Non-destructive measurements for determining the performance of a CMUT ultrasound transducer
Determining the spatial pressure field on cMUT
A combination of different methods is often used to characterize new ultrasonic transducers. Finite element simulations predict the transducer’s behaviour, taking the surrounding medium into consideration too. You can then measure new transducer prototypes with microscope-based laser vibrometers such as the Polytec MSA Micro System Analyzer, to directly determine the mechanical frequency response of the sound transducer surface. In doing so, you will come to appreciate the large frequency bandwidth and real time capability that you use to reliably and accurately measure transient processes in particular.
IMEC in Belgium characterized a unique cMUT with the Polytec MSA and, based on the results, determined the spatial pressure field in the transfer medium using the Rayleigh integral method. The results were subsequently confirmed with independent hydrophone measurements.
Microstructure characterization
Related products
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The all-in-one optical measurement solution for static and dynamic 3D characterization of MEMS and microstructures- now for up to 8 GHz! The MSA-600 enhances microsystem development and quality inspections - also allowing testing on wafer-level when integrated into commercially available probe stations.
MSA IRIS Measurement Service
This brand new, patented measurement technology allows for comprehensive and representative analysis of Si encapsulated MEMS, measuring dynamics right through silicon caps. Our PolyXperts are looking forward to receiving your capped MEMS samples for modal testing, feasibility studies and consulting throughout all phases from development over prototyping to manufacturing of your encapsulated microstructures.
MSA-100-3D Micro System Analyzer
The 3D Micro System Analyzer records vibration components in all three spatial directions at once. The optical measurement system enables high-resolution 3D vibration analysis from DC up to 25 MHz with amplitude resolutions in the sub-picometer range, for both in-plane and out-of-plane vibration components.
Further applications
- Wafer-level
![Deflection shape after modal testing microacoustic device on wafer level]( "Deflection shape after modal testing microacoustic device on wafer level")
Deflection shape after modal testing microacoustic device on wafer level - Prototype testing
![MEMS prototype testing, here a CMOS / MEMS co-integrated flow microsensor, (C) University of Louvain, Belgium]( "MEMS prototype testing, here a CMOS / MEMS co-integrated flow microsensor, (C) University of Louvain, Belgium")
MEMS prototype testing, here a CMOS / MEMS co-integrated flow microsensor, (C) University of Louvain, Belgium - SAWs and BAWs
![Dynamic measurement of a SAW surface acoustic wave filter]( "Dynamic measurement of a SAW surface acoustic wave filter")
Dynamic measurement of a SAW surface acoustic wave filter - Micro mechanics
![Laser vibration measurement for testing micro-mechanical MEMS]( "Laser vibration measurement for testing micro-mechanical MEMS")
Laser vibration measurement for testing micro-mechanical MEMS - MEMS reliability testing
![Vibration measurements for reliability testing on MEMS in a vacuum chamber]( "Vibration measurements for reliability testing on MEMS in a vacuum chamber")
Vibration measurements for reliability testing on MEMS in a vacuum chamber - Bio MEMS
![Deflection shape of cMUT transducer array, University of Alberta]( "Deflection shape of cMUT transducer array, University of Alberta")
Deflection shape of cMUT transducer array, University of Alberta
