Wearable, high-resolution and deep penetration are shown as the emerging trends in medical Ultrasound imaging. To achieve this, multi-frequency Ultrasound Piezoelectric Micromachined Ultrasonic Transducers (PMUT) are highly recommended due to their capabilities of overcoming the intrinsic trade-off between penetration depth and image resolution, their low-energy consumption and their high density compared to the traditional single-frequency bulk transducer. Currently we have already developed the 1st generation polymer-based multi-frequency PMUT arrays intended for imaging.
Within this project, we will design and characterize the new generation of multi-frequency polymer-based PMUTs. At the end of the project we will compare their performance with the previous generation towards medical imaging applications. The project consist of several parts:
Finite-element method (FEM) models of single PMUTs will be firstly investigated for different dimensions and shape to target several resonance frequencies using COMSOL Multiphysics.
- Laser Doppler vibrometer (LDV) measurement
The membrane velocity at different resonances and the vibration modes will be measured on a single device in air and in water by using a Polytec MSA-500 laser Doppler vibrometer.
- Acoustic characterization
The acoustic output of a small array of PMUT will be characterized at the different resonance frequencies using an Onda hydrophone. Thereafter the pulse-echo properties will be investigated by using the existing ultrasound platform, Verasonics Vantage.
- Comparison with the 1st generation
The resonance frequencies, bandwidths and mode shapes as well as the acoustic output will be compared to the previous generation and further improvements will be proposed.
Fig. 1. The 1st generation polymer-based PMUT array and its cross-section (a) and its LDV characterization at a frequency sweep (b).
 Sun, Changhe, et al. IEEE Sensors Journal 19.3 (2019): 860-867
Type of project: Internship, Thesis
Duration: 6-12 months
Required degree: Master of Engineering Technology, Master of Science, Master of Engineering Science
Required background: Biomedical engineering, Bioscience Engineering, Electromechanical engineering, Electrotechnics/Electrical Engineering, Mechanical Engineering, Nanoscience & Nanotechnology, Physics
Supervising scientist(s): For further information or for application, please contact: Hang Gao (Hang.Gao@imec.be) and Margo Billen (Margo.Billen@imec.be) and Veronique Rochus (Veronique.Rochus@imec.be)
Imec allowance will be provided for students studying at a non-Belgian university.