Efficient Galvanic Body-Coupled Powering for Wireless Implanted Neurostimulators

• Published in: Biomedical Circuits and Systems Conference pp. 1 - 5
• Main Authors: Omi, Asif Iftekhar, Farina, Emma, Jiang, Anyu, Khalifa, Adam, Srinivasan, Shriya, Chatterjee, Baibhab
• Format: Conference Proceeding
• Language: English
• Published: IEEE 24.10.2024
• Subjects: Biomedical Implants; Body-coupled Powering (BCP); Circuits; Electrodes; Galvanic; Implants; Prototypes; Recording; Resilience; Transmitters; Wearable; Wireless communication; Wireless power transfer; Wireless Power Transfer (WPT)
• ISSN: 2766-4465
• DOI: 10.1109/BioCAS61083.2024.10798261

Body-coupled powering (BCP) is an innovative wireless power transfer (WPT) technique, recently explored for its potential to deliver power to cutting-edge biomedical implants such as nerve/muscle stimulators. This paper demonstrates the efficient technique of designing WPT systems embedding BCP via galvanic coupling (G-BCP). The G-BCP configuration utilizes two metal circular rings surrounding the body area of interest as the transmitter (TX) electrodes required for galvanic (differential) excitation and a wireless implant as the receiver (RX) equipped with two electrodes for differential power reception accordingly. By focusing on the unique advantages of this approach-such as enhanced targeting accuracy, improved power transfer efficiency (PTE), and favorable tissue penetration characteristics, G-BCP emerges as a superior alternative to traditional WPT methods. A comprehensive analysis is conducted to obtain the optimized device parameters while simultaneously allowing flexible placement of implants at different depths and alignments. To substantiate the proposed design concept, a prototype was simulated in Ansys HFSS, employing a multi-layered tissue medium of 10 mm radius and targeting the sciatic nerve of a rat. Impressively, this prototype achieves \gt 20 \% PTE at 1.25 GHz, with the implant (radius of RX electrodes =1 \mathrm{~mm}) located 2 mm deep inside the tissue model having complex load impedance of R_{\text {load}}=1000 \Omega and C_{\text {load}}=5 p F. Therefore, the G-BCP-based wirelessly powered microdevices are envisaged to be a key enabler in neural recording and stimulation, specifically for the peripheral nervous system, enhancing therapeutic outcomes and patient experiences.