RPG-HBC: Reconfigurable Passive Galvanic Human Body Communication for Bioelectronic Implants Under Varying Channel Conditions

Wireless communication is vital for bioelectronic implants to transmit sensor data [1], [2]. Traditional methods like RF face high absorption in body tissues, leading to high power use and safety concerns [3]. Inductive coupling reduces absorption but has limited data rates [4], [5]. Emerging modalities such as optics [6], ultrasound [7], and magnetoelectric [8] have power, carrier frequency, and data rate trade-offs. Human-body communication (HBC) leverages body tissue as a communication medium and has been explored for wearable [9] and implants[10]. Capacitive HBC offers high energy efficiency and data rates for wearable [9], [11] but is less effective when implanted due to the lack of a ground path [12]. Galvanic HBC (G-HBC) uses two pairs of electrodes-one implanted and one on the skin surface-to transmit data by driving currents through the body (Fig. 1 top) [13], [14]. While G-HBC achieves high data rates with low power consumption and offers security [15], it is hindered by varying tissue conditions that alter electrode impedance, degrading performance [16]–[20].