Analog Front-end for Microfabricated Ultrasound Transducer Arrays
Number of Students : 2
Guides : Hardik J Pandya
Ultrasound imaging uses high-frequency acoustic waves generated and sensed using a piezoelectric transducer to visualize tissue anatomy. Ultrasound imaging is widely used for abdominal imaging, bone fragility measurements, breast tissue imaging, fetal heart rate monitoring, blood flow measurements (Doppler ultrasound), etc. With the advent of microfabrication technology, the possibility of using two kinds of micromachined ultrasound transducers (MUT) has emerged: capacitive MUTs (cMUTs) and piezoelectric MUTs (pMUTS). Piezoelectric micromachined ultrasonic transducers (pMUTs) use a piezoelectric layer adhered to an inert membrane and operate in flexural mode, exploiting the piezoelectric coefficient d31 for vibration. By applying an electrical field to the film, the resulting strain (due to the direct piezoelectric effect) causes the structure to bend and generate acoustic waves. Arrays of pMUTs can be fabricated to improve lateral and axial resolution compared to a conventional 1D piezoelectric transducer. Using 3-16 rows of pMUTs, an image slide with extended depth of field and contrast resolution can be obtained. Along with an array of pMUTs, selecting the correct operation frequency is crucial. Higher frequencies can provide better spatial resolution, but at the cost of depth of penetration. In the proposed project, the students are expected to develop an analog front-end that couples the microfabricated pMUT arrays to a controller unit for beam forming and a data acquisition unit for signal processing and image generation. At the end of the project, the students will learn Analog electronic circuit design for high-speed and precision applications, Electronic module development for microelectromechanical systems (MEMS), Electronic and MEMS packaging, Ultrasound imaging, and Biomedical device design. All students will be provided access to Class 100/1000 clean room facilities and training on pMUTs fabrication. The work provides opportunities to interact with experts in ultrasound imaging as well as to interact with Oncosurgeons.
