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This paper presents the design, implementation, and experimental evaluation of a wireless biomedical implant platform exploiting the magnetoelectric effect for wireless power and bi-directional communication. As an emerging wireless power transfer method, magnetoelectric is promising for mm-scaled bio-implants because of its superior misalignment sensitivity, high efficiency, and low tissue absorption compared to other modalities [46, 59, 60]. Utilizing the same physical mechanism for power and communication is critical for implant miniaturization, but low-power magnetoelectric uplink communication has not been achieved yet. For the first time, we design and demonstrate near-zero power magnetoelectric backscatter from the mm-sized implants by exploiting the converse magnetostriction effects. The system for demonstration consists of an 8.2-mm3 wireless implantable device and a custom portable transceiver. The implant's ASIC interfacing with the magnetoelectric transducer encodes uplink data by changing the transducer's load, resulting in resonance frequency changes for frequency-shift-keying modulation. The magnetoelectrically backscattered signal is sensed and demodulated through frequency-to-digital conversion by the external transceiver. With design optimizations in data modulation and recovery, the proposed system archives > 1-kbps data rate at the 335-kHz carrier frequency, with a communication distance greater than 2 cm and a bit error rate less than 1E-3. Further, we validate the proposed system for wireless stimulation and sensing, and conducted ex-vivo tests through a 1.5-cm porcine tissue. The proposed magnetoelectric backscatter approach provides a path towards miniaturized wireless bio-implants for advanced biomedical applications like closed-loop neuromodulation.
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A Power Budget Analysis for an Implantable UWB Transceiver for Brain Neuromodulation Application
The next evolutionary step in biological signal monitoring will be enabled by wireless communication. Low power and cost-efficient wireless transceivers are currently being employed for implantable medical devices (IMDs), in addition to military and civilian applications such as monitoring, surveillance, and home automation. The major goal of this paper is to do a thorough and realistic link budget analysis for an implantable wireless transceiver operating in the 3–5 GHz ultrawideband frequency with a link distance of 2 m (which includes 10 mm of brain tissue layer and 1.99 m of air medium), data rate of 100 Mbps with On-Off keying (OOK) modulation, and a minimum receiver sensitivity of −58.01 dBm. The proposed power budget analysis is particularly well suited for distributed brain implant applications as it models the path loss including the tissue layer without compromising the spectrum regulation imposed by the Federal Communications Commission (FCC) for UWB communication.
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- Award ID(s):
- 1943990
- PAR ID:
- 10394684
- Date Published:
- Journal Name:
- 2022 IEEE USNC-URSI Radio Science Meeting (Joint with AP-S Symposium)
- Page Range / eLocation ID:
- 92 to 93
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.23919/USNC-URSI52669.2022.9887429
