All Publications


  • Multi-Access Networking with Wireless Ultrasound-Powered Implants. IEEE Biomedical Circuits and Systems Conference : healthcare technology : [proceedings]. IEEE Biomedical Circuits and Systems Conference Chang, T. C., Wang, M. n., Arbabian, A. n. 2019; 2019

    Abstract

    Multi-access networking with miniaturized wireless implantable devices can enable and advance closed-loop medical applications to deliver precise diagnosis and treatment. Using ultrasound (US) for wireless implant systems is an advantageous approach as US can beamform with high spatial resolution to efficiently power and address multiple implants in the network. To demonstrate these capabilities, we use wirelessly powered mm-sized implants with bidirectional communication links; uplink data communication measurements are performed using time, spatial, and frequency-division multiplexing schemes in tissue phantom. A 32-channel linear transmitter array and an external receiver are used as a base station to network with two implants that are placed 6.5 cm deep and spaced less than 1 cm apart. Successful wireless powering and uplink data communication around 100 kbps with a measured bit error rate below 10-4 are demonstrated for all three networking schemes, validating the multi-access networking feasibility of US wireless implant systems.

    View details for DOI 10.1109/BIOCAS.2019.8919144

    View details for PubMedID 31989118

  • Multi-Access Networking with Wireless Ultrasound-Powered Implants Chang, T., Wang, M., Arbabian, A., IEEE IEEE. 2019
  • Ultrasonic Implant Localization for Wireless Power Transfer: Active Uplink and Harmonic Backscatter Wang, M. L., Chang, T., Arbabian, A., IEEE IEEE. 2019: 818–21
  • Ultrasonic Implant Localization for Wireless Power Transfer: Active Uplink and Harmonic Backscatter. IEEE International Ultrasonics Symposium : [proceedings]. IEEE International Ultrasonics Symposium Wang, M. L., Chang, T. C., Arbabian, A. n. 2019; 2019: 818–21

    Abstract

    Efficient ultrasonic power transfer to implantable devices requires precise transmitter beamforming to the receiver and can quickly degrade with small changes in implant location. Ultrasound localization can be used to find and track implants in the body to maintain an efficient link. We present a framework to calculate localization accuracy showing that sub-mm accuracy is obtainable using only three receive channels. A harmonic backscatter approach, which passively provides contrast in the frequency domain without active load modulation is compared to active uplink from the implant. The localization accuracy using both active uplink and harmonic backscatter from the implant power receiver is characterized using a linear array probe. The measured location standard deviation is nearly two orders of magnitude smaller than the half-power beamwidth of the array focal spot. Finally, beamforming using the measured location information increases the available power by over 20 × compared to an unfocused beam.

    View details for PubMedID 31988699

  • Wireless Data Links for Next-Generation Networked Micro-Implantables Wang, M. L., Baltsavias, S., Chang, T., Weber, M. J., Charthad, J., Arbabian, A., IEEE IEEE. 2018
  • Exploiting spatial degrees of freedom for high data rate ultrasound communication with implantable devices APPLIED PHYSICS LETTERS Wang, M. L., Arbabian, A. 2017; 111 (13)

    View details for DOI 10.1063/1.5004967

    View details for Web of Science ID 000412074000042

  • Closed-Loop Ultrasonic Power and Communication with Multiple Miniaturized Active Implantable Medical Devices Wang, M. L., Chang, T., Teisberg, T., Weber, M. J., Charthad, J., Arbabian, A., IEEE IEEE. 2017
  • A 30.5mm(3) Fully Packaged Implantable Device with Duplex Ultrasonic Data and Power Links Achieving 95kb/s with < 10(-4) BER at 8.5cm Depth Chang, T., Wang, M. L., Charthad, J., Weber, M. J., Arbabian, A., IEEE IEEE. 2017: 460
  • The power of sound: miniaturized medical implants with ultrasonic links Wang, M. L., Chang, T., Charthad, J., Weber, M. J., Arbabian, A., George, T., Dutta, A. K., Islam, M. S. SPIE-INT SOC OPTICAL ENGINEERING. 2017

    View details for DOI 10.1117/12.2263877

    View details for Web of Science ID 000411756000020

  • Sound Technologies, Sound Bodies IEEE MICROWAVE MAGAZINE Arbabian, A., Chang, T. C., Wang, M. L., Charthad, J., Baltsavias, S., Fallahpour, M., Weber, M. J. 2016; 17 (12): 39-54
  • Design of Tunable Ultrasonic Receivers for Efficient Powering of Implantable Medical Devices With Reconfigurable Power Loads IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL Chang, T. C., Weber, M. J., Wang, M. L., Charthad, J., Khuri-Yakub, B. (., Arbabian, A. 2016; 63 (10): 1554-1562

    Abstract

    Miniaturized ultrasonic receivers are designed for efficient powering of implantable medical devices with reconfigurable power loads. Design parameters that affect the efficiency of these receivers under highly variable load conditions, including piezoelectric material, geometry, and operation frequency, are investigated. Measurements were performed to characterize electrical impedance and acoustic-to-electrical efficiency of ultrasonic receivers for off-resonance operation. Finally, we propose, analyze, and demonstrate adaptive matching and frequency tuning techniques using two different reconfigurable matching networks for typical implant loads from 10 [Formula: see text] to 1 mW. Both simulations and measurements show a significant increase in total implant efficiency (up to 50 percentage points) over this load power range when operating off-resonance with the proposed matching networks.

    View details for DOI 10.1109/TUFFC.2016.2606655

    View details for Web of Science ID 000385720000008

    View details for PubMedID 27623580