2021 journal article
A Wearable Ultrasonic Neurostimulator-Part I: A 1D CMUT Phased Array System for Chronic Implantation in Small Animals
IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS, 15(4), 692–704.
author keywords: ASIC; brain stimulation; capacitive micromachined ultrasonic transducer (CMUT); freely behaving animals; neurostimulation; ultrasound
MeSH headings : Animals; Equipment Design; Transducers; Ultrasonics; Ultrasonography; Wearable Electronic Devices
TL;DR:
A wireless ultrasonic neurostimulator, aiming at a truly wearable device for brain stimulation in small behaving animals, and hydrophone-based acoustic measurements were performed to demonstrate the beam forming and steering capability of the proposed system.
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3. Good Health and Well-being
(Web of Science)
7. Affordable and Clean Energy
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Source: Web Of Science
Added: September 27, 2021
In this work, we present a wireless ultrasonic neurostimulator, aiming at a truly wearable device for brain stimulation in small behaving animals. A 1D 5-MHz capacitive micromachined ultrasonic transducer (CMUT) array is adopted to implement a head-mounted stimulation device. A companion ASIC with integrated 16-channel high-voltage (60-V) pulsers was designed to drive the 16-element CMUT array. The ASIC can generate excitation signals with element-wise programmable phases and amplitudes: 1) programmable sixteen phase delays enable electrical beam focusing and steering, and 2) four scalable amplitude levels, implemented with a symmetric pulse-width-modulation technique, are sufficient to suppress unwanted sidelobes (apodization). The ASIC was fabricated in the TSMC 0.18-<inline-formula><tex-math notation="LaTeX">${\mu \rm {m}}$</tex-math></inline-formula> HV BCD process within a die size of 2.5 × 2.5 <inline-formula><tex-math notation="LaTeX">${\rm {mm}^2}$</tex-math></inline-formula>. To realize a completely wearable system, the system is partitioned into two parts for weight distribution: 1) a head unit (17 mg) with the CMUT array, 2) a backpack unit (19.7 g) that includes electronics such as the ASIC, a power management unit, a wireless module, and a battery. Hydrophone-based acoustic measurements were performed to demonstrate the focusing and beam steering capability of the proposed system. Also, we achieved a peak-to-peak pressure of 2.1 MPa, which corresponds to a spatial peak pulse average intensity (<inline-formula><tex-math notation="LaTeX">$\mathrm{I_{SPPA}}$</tex-math></inline-formula>) of 33.5 <inline-formula><tex-math notation="LaTeX">${\rm {W}/\rm {cm}^2}$</tex-math></inline-formula>, with a lateral full width at half maximum (FWHM) of 0.6 mm at a depth of 3.5 mm.