Earbud-Based UWB Data Link for Multichannel Brain Neural Recording and Stimulation Interfaces

This paper proposes a novel earbud-based wireless Ultra-Wideband (UWB) data link consisting of an implantable transmitter (Tx) and an earbud-based wearable receiver (Rx) antennas. The Tx UWB antenna is an implant and designed to be located in the backside of the ear, right beneath the skin and close to the Rx antenna. The Rx antenna is designed to be formed around a standard earbud, which is 1) convenient to align it with the Tx antenna for long-term and frequent usages and 2) barely noticeable (avoiding any wearables on top of or around the head). The proposed UWB link is modeled and simulated with ANSYS HFSS, including the human head-ear inhomogeneous realistic tissue model. The performance of the proposed UWB link is evaluated (using HFSS) that confirms 1) return losses < −10dB, 2) the link frequency response > −40 dB at the targeted frequency range (3.6 to 6.8 GHz), 3) the appropriate location of Rx antenna for absorbing radiated Electromagnetic field generated by Tx antenna, and 4) the average specific absorption rate (SAR) < 1.41 W/kg with transmitted power of 5 mW. In addition, the placement of the Rx antenna is examined under two tilted conditions of 0° and 15°, which ensures the robustness of the proposed design against typical angular misalignment during earbud-wearing. The link feasibility is verified by calculating the required worst-case receiver sensitivity of −39.52 dBm.