A Wireless Network of 8.8-mm³ Bio-Implants Featuring Adaptive Magnetoelectric Power and Multi-Access Bidirectional Telemetry

This paper presents a hardware platform for wireless mm-sized bio-implant networks, exploiting adaptive magnetoelectric power transfer and novel schemes for efficient bidirectional multi-access communication. The closed-loop power control mitigates power delivery fluctuations caused by distance and alignment change and avoids redundant power of the external transceiver. The system also enables simultaneous power and time-domain modulated downlink data with a 5% peak power transfer efficiency and a 62.3-kbps maximum data rate at 340-kHz carrier frequency; multi-access uplink of all the implants enabled by individually programmed IF with a 40-kbps maximum data rate at 31-MHz carrier frequency; and more than 6-cm distance between the implant and the external TRX.