S-MRUT: Sectored-Multi Ring Ultrasonic Transducer for Selective Powering of Brain Implants

TY - JOUR

T1 - S-MRUT

T2 - Sectored-Multi Ring Ultrasonic Transducer for Selective Powering of Brain Implants

AU - Hosseini, Seyedsina

AU - Laursen, Kjeld

AU - Rashidi, Amin

AU - Mondal, Tanmay

AU - Corbett, Brian

AU - Moradi, Farshad

PY - 2021/1

Y1 - 2021/1

N2 - One of the main challenges of the current ultrasonic transducers for powering brain implants is the complexity of focusing ultrasonic waves in various axial and lateral directions. The available transducers usually use electrically controlled phased array for beamforming the ultrasonic waves, which increases the complexity of the system even further. In this paper, we propose a straightforward solution for selective powering of brain implants to remove the complexity of conventional phased arrays. Our approach features a Sectored-Multi Ring Ultrasonic Transducer (S-MRUT) on a single piezoelectric sheet, specifically designed for powering implantable devices for optogenetics in freely moving animals. The proposed uni-directional S-MRUT is capable of focusing the ultrasonic waves on brain implants located at different depths and regions of the brain. The S-MRUT is designed based on Fresnel Zone Plate (FZP) theory, simulated in COMSOL, and fabricated with microfabrication process. The acoustic profile of the seven different configurations of the SMRUT were measured using a hydrophone with the total number of 7436 grid points. The measurements show the ability of the proposed S-MRUT to sweep the focus point of the acoustic waves in the axial direction in depths of 1 – 3mm, which is suitable for powering implants in the striatum of the mouse. Furthermore, the proposed S-MRUT demonstrates a steering area with the average radius of 0:862mm, and 0:678mm in experiments, and simulations, respectively. The S-MRUT is designed with the size of 3.8 × 3.8 × 0.5mm3 and the weight of 0:054gr, showing that it is compact and light enough to be worn by a mouse. Finally, the S-MRUT was tested in our measurement setup, where it successfully transfers sufficient power to a 2:8mm3 optogentic stimulator to turn on a microLED on the stimulator.

AB - One of the main challenges of the current ultrasonic transducers for powering brain implants is the complexity of focusing ultrasonic waves in various axial and lateral directions. The available transducers usually use electrically controlled phased array for beamforming the ultrasonic waves, which increases the complexity of the system even further. In this paper, we propose a straightforward solution for selective powering of brain implants to remove the complexity of conventional phased arrays. Our approach features a Sectored-Multi Ring Ultrasonic Transducer (S-MRUT) on a single piezoelectric sheet, specifically designed for powering implantable devices for optogenetics in freely moving animals. The proposed uni-directional S-MRUT is capable of focusing the ultrasonic waves on brain implants located at different depths and regions of the brain. The S-MRUT is designed based on Fresnel Zone Plate (FZP) theory, simulated in COMSOL, and fabricated with microfabrication process. The acoustic profile of the seven different configurations of the SMRUT were measured using a hydrophone with the total number of 7436 grid points. The measurements show the ability of the proposed S-MRUT to sweep the focus point of the acoustic waves in the axial direction in depths of 1 – 3mm, which is suitable for powering implants in the striatum of the mouse. Furthermore, the proposed S-MRUT demonstrates a steering area with the average radius of 0:862mm, and 0:678mm in experiments, and simulations, respectively. The S-MRUT is designed with the size of 3.8 × 3.8 × 0.5mm3 and the weight of 0:054gr, showing that it is compact and light enough to be worn by a mouse. Finally, the S-MRUT was tested in our measurement setup, where it successfully transfers sufficient power to a 2:8mm3 optogentic stimulator to turn on a microLED on the stimulator.

KW - Acoustic transducer

KW - Acoustics

KW - Brain implant

KW - Electrodes

KW - Mice

KW - Neural implants

KW - Optogenetics

KW - Transducers

KW - Ultrasonic transducers

KW - Uni-directional transducer

UR - http://www.scopus.com/inward/record.url?scp=85086732102&partnerID=8YFLogxK

U2 - 10.1109/TUFFC.2020.3001084

DO - 10.1109/TUFFC.2020.3001084

M3 - Journal article

C2 - 32746178

SN - 0885-3010

VL - 68

SP - 191

EP - 200

JO - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control

JF - IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control

IS - 1

M1 - 9112273

ER -