MAS.S65

Piezoelectrics for Ultrasonic Biomedical Devices

Style

Teamwork; Collective

To pass, you must: (i) attend all the class lectures, (ii) participate during the experimental/simulation sessions, and (iii) submit the project(s) at the end of course. By the end of Class #1, students must decide whether to register or drop the course.



Overview

This is a special topic on piezoelectric materials and devices, which have become a leading source of functional and intelligent electronics in a vast array of applications, from personal healthcare to industrial equipment. The instructor anticipates that this unique course will shed light on the present state of research and development within the community of piezoelectric materials and ultrasound devices for biomedical applications. It begins with a comprehensive summary of the history of piezoelectrics and current hot research topics. Second, it covers all aspects of the materials starting from fundamental concepts, including the theory of piezoelectricity, and the physics of piezoelectric materials and their characteristics. Third, it demonstrates advanced electronic devices, including sensors, actuators, harvesters, and transducers. Fourth, it will cover cutting-edge applications of piezoelectric ultrasound for medical imaging, energy transfer, and neurostimulations. Last but not least, students will be trained on modelling ultrasonic propagation to design medical devices using different simulation software like COMSOL and PiezoCAD. In the meantime, students will obtain practical expertise in synthesizing and characterizing piezoelectric materials and manufacturing and measuring piezoelectric devices for engineering and biomedical applications. On the course website, course-related books/articles/notes/video tutorials are provided. The final projects are to submit digital drawings (2D/3D) and their corresponding simulation results of the proposed piezoelectric medical devices based on the interest of the students.

  • Cleanroom (YellowBox) open hours will be held on Tuesdays from 10am-12pm.



    • Objectives

    1. To gain knowledge from experts in the piezoelectric and ultrasound research field,
    2. To understand the impact of microfabricated devices on society,
    3. To encourage participation in class by the asking of questions,
    4. To experience the piezoelectric materials/devices fabrication and characterization
    5. To draw and simulate the performance of different piezoelectric ultrasound based medical devices
    6. To write a scientific report on the research findings and experiments as a team



    Schedule (Lecture sessions: ≥3 hrs/class; Experimental/Simulation sessions: ≥3 hrs/class)


    Schedule:


    Class 1:


    Introduction


    1. Syllabus overview & what you can learn from this class
    2. The smart materials & the role of piezoelectrics
    3. Dielectrics/piezoelectrics/ferroelectrics subsets
    4. Origin of piezoelectric phenomenon
    5. Structure & piezoelectric equations
    6. Parameters, full matrix, and governing equations
    7. Piezoelectric constants and important piezoelectric parameters/factors
    8. Resonant crystal geometries & modes of vibration
    9. Fundamental & harmonic frequencies and corresponding modes of vibrations
    10. Perovskite structure and importance of Curie temperature
    11. Tetragonal, orthorhombic, rhombohedral, etc. phases
    12. Importance of morphotropic & polymorphic phase boundary

    Class 2:


    (A) Piezoelectric materials: crystal and ceramics


    1. Different types of ceramics: lead-based and lead-free types
    2. Fabrication and preparation
    3. Important crystal and ceramic properties e.g., longitudinal velocity, impedance, d33, k33, dieletric constant, loss, etc.
    4. Performance and recent important work

    (B) Piezoelectric materials: films (inorganic and organic)


    1. Different types of films
    2. Fabrication and preparation
    3. Important properties
    4. Performance and recent important work

    (C) Piezoelectric materials: composites


    1. 10 types of connection
    2. Fabrication and preparation of composites
    3. Important properties
    4. Performance and recent important work

    Class 3:


    (A) Piezoelectric devices: sensors


    1. device examples
    2. performance
    3. applications

    (B) Piezoelectric devices: actuators


    1. device examples
    2. performance
    3. applications

    (C) Piezoelectric devices: harvesters


    1. device examples
    2. performance
    3. applications

    Class 4: Experimental


    Piezoelectric materials characterization


    1. Exhibit different piezoelectric materials: ceramics/crystal/thin film
    2. Impedance analysis
    3. LDV measurement
    4. Parameters calculation

    Class 5:


    Introduction of ultrasound


    1. Physics
    2. Propagation model: wave equations & interaction of Sound and Media
    3. Importance of frequency/wavelength/velocity, impedance matching, & attenuation
    4. How to generate ultrasound wave
    5. Ultrasound transducers
    6. Why arrays: 1D array, 1.5D array, 2D array
    7. Types of arrays (linear, curvilinear, phased, annular, sector, theta-theta, PMUT array, etc.) and comparison, and selection criteria for end-use applications
    8. Importance of understanding tissue attenuation coefficient and acoustic loss attenuation of a soft tissue as a function of frequency

    Class 6:


    Ultrasound transducers


    1. The structure of ultrasound transducers
    2. Performance parameters with examples based on different end uses
    3. Important factors in US: intensity, amplitude, pulse duration, duty cycle
    4. Importance of press focusing, focusing lens, matching, and backing layers
    5. Equivalent circuit transducer model: KLM model
    6. Demonstrating AUTOCAD application for microfabricated array and electrode trace designing

    Class 7:


    Ultrasound applications: imaging


    1. Background of ultrasound imaging
    2. Different modes of imaging: A, B, M, and Doppler mode
    3. Performance parameters with examples based on different end uses
    4. Examples of ultrasound imaging
    5. Examples of different transducer array designs for imaging (comparing previous & recent works)
    6. Importance of piezoelectric material selection for imaging (comparing previous & recent works)

    Class 8:


    Ultrasound applications: imaging


    1. Beamforming & steering
    2. Pulse-echo/Chirp
    3. Axial & lateral dimensions of the beam
    4. Delay and sum method for image generation
    5. Signal processing
    6. Circuit design and working principle
    7. Ultrasound imaging analysis

    Class 9:


    Ultrasound applications: wireless energy transfer & communication


    1. Physics
    2. Applications
    3. Parameters for ultrasound energy harvesting sensitivity
    4. Importance of receiver/transmitter design selection
    5. Transmitter & receiver parameters for energy transfer & communication
    6. Examples of different ultrasonic receiver/transmitter designs for energy transfer (comparing previous & recent works)
    7. Importance of piezoelectric materials selection for energy transfer (comparing previous & recent works)

    Class 10:


    Experiment


    1. Fundamental of PiezoCAD for piezoelectric transducer
    2. Discussion on simulation parameters for ultrasound transducer
    3. Demonstrating PiezoCAD simulation experiments to investigate the effect of design parameters for different end-uses of:
      1. ultrasonic transducer for medical imaging and
      2. ultrasonic transmitting transducer for energy transfer

    Class 11:


    Ultrasound applications: Stimulation/therapy, drug delivery & tissue characterization with low and high frequency transducer


    1. Physics
    2. Applications
    3. Propagation model
    4. Frequency selection like HIFU, LIFU, etc.
    5. Different stimulation techniques: focused, pulsed, continuous, etc.
    6. Neurostimulation, thermal ablation, lithotripsy, elastography, therapeutic contrast agent
    7. Tissue characterization: radiology, cardiac application, etc.
    8. Drug delivery: methodology and current state of the earth
    9. Examples of different ultrasonic device designs for stimulation/therapy, drug delivery, and tissue characterization

    Class 12:


    Class & Experiment


    (A) Piezoelectric Micromachined Ultrasound Transducer (PMUT)


    1. Physics
    2. Applications
    3. Propagation model
    4. Frequency and materials selection & others

    (B) AUTOCAD application for designing microfabricated PMUTs


    (C) Demonstrating COMSOL/On-Scale simulation experiments for profiling the piezoelectric ultrasound stimulation and investigate the effect of design parameters



    Class 13:


    Project Realization #1:


    Medical imaging transducer design: Draw 2D/3D image of your piezoelectric transducer & apply simulation using PiezoCAD for its performance characterization



    Class 14:


    Project Realization #2:


    Medical imaging transducer design: Draw 2D/3D image of your piezoelectric transducer & apply simulation using PiezoCAD for its performance characterization



    Class 15:


    Project Realization #3:


    Neurostimulator (bulk or/and PMUT) design: Draw 2D/3D image of your piezoelectric stimulator & apply simulation using COMSOL for its performance characterization